SEC Form SC 14D9 filed by Sage Therapeutics Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14D-9

Solicitation/Recommendation Statement

Under Section 14(d)(4) of the Securities Exchange Act of 1934

Sage Therapeutics, Inc.

(Name of Subject Company)

(Name of Person Filing Statement)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

78667J108

(CUSIP Number of Class of Securities)

Gregory Shiferman

Sage Therapeutics, Inc.

Senior Vice President, General Counsel

55 Cambridge Parkway

Cambridge, MA 02142

(617) 299-8380

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications

on Behalf of the Person Filing Statement)

With copies to:

Graham Robinson, P.C.

Laura Knoll, P.C.

Merric Kaufman

Kirkland & Ellis LLP

200 Clarendon Street

Boston, Massachusetts 02116

(617) 385-7500

TABLE OF CONTENTS

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Item 1. Subject Company Information.

Name and Address.

The name of the subject company to which this Solicitation/Recommendation Statement on Schedule 14D-9 (together with any exhibits and annexes attached hereto, as it may be amended or supplemented, this “Schedule 14D-9”) relates is Sage Therapeutics, Inc., a Delaware corporation. The address of the principal executive offices of Sage is 55 Cambridge Parkway, Cambridge, Massachusetts 02142, and its telephone number is (617) 299-8380. In this Schedule 14D-9, “we,” “us,” “our,” “Company” and “Sage” refer to Sage Therapeutics, Inc.

Securities.

The title of the class of equity securities to which this Schedule 14D-9 relates is the common stock of Sage, $0.0001 par value per share (collectively, the “Shares”). As of the close of business on June 27, 2025, there were (i) 62,631,252 Shares issued, 62,628,219 Shares outstanding and 3,033 were held by Sage as treasury shares; (ii) 5,000,000 shares authorized of preferred stock, par value $0.0001 par value per share, of which no shares are issued or outstanding; (iii) 5,570,004 Shares issuable upon the exercise of outstanding options to purchase Shares (the “Company Options”), of which 1,137,942 Company Options are In the Money Options (as defined below in the section captioned “Item 2. Identity and Background of Filing Person—Tender Offer”) with a weighted average exercise price of $6.95; (iv) 1,916,330 Shares issuable upon the vesting or settlement of outstanding restricted stock units (“Company RSUs”); (v) 1,219,921 Shares issuable upon the vesting or settlement of outstanding restricted stock units whose vesting is conditioned in full or in part based on the achievement of performance goals or metrics (“Company PSUs”) (assuming vesting pursuant to the Merger Agreement) and 1,529,371 Shares issuable upon the vesting or settlement of outstanding Company PSUs (assuming maximum level of performance and achievement of all applicable performance goals); and (vii) 866,758 Shares available for future issuance under Sage’s 2014 Employee Stock Purchase Plan, as amended.

Item 2. Identity and Background of Filing Person.

Name and Address.

The name, address and telephone number of Sage, which is the person filing this Schedule 14D-9, are set forth above in the section captioned “Item 1. Subject Company Information—Name and Address.”

Tender Offer.

This Schedule 14D-9 relates to the Tender Offer Statement on Schedule TO filed with the Securities and Exchange Commission (the “SEC”) on July 2, 2025 (together with any amendments and supplements thereto, the “Schedule TO”) by (i) Supernus Pharmaceuticals, Inc., a Delaware corporation (“Supernus” or “Parent”) and (ii) Saphire, Inc., a Delaware corporation and a wholly owned subsidiary of Supernus (“Purchaser”). The Schedule TO relates to the tender offer to purchase all of the outstanding Shares, for (i) $8.50 per Share, net to the seller in cash, without interest and subject to any withholding of taxes, (the “Closing Amount”), plus (ii) one contingent value right per Share (a “CVR”) which represents the right to receive up to $3.50 per Share upon the satisfaction of specified milestones (as described below in the section captioned “Item 3. Past Contacts, Transactions, Negotiations and Agreements—Arrangements with Purchaser, Parent, and their Affiliates—CVR Agreement”), net to the seller in cash, without interest and subject to any withholding of taxes, pursuant to the CVR Agreement (as defined below in the section captioned “Item 3. Past Contacts, Transactions, Negotiations and Agreements—Arrangements with Purchaser, Parent, and their Affiliates—CVR Agreement”) (the Closing Amount plus one CVR collectively, the “Offer Price”), upon the terms and subject to the conditions set forth in the Offer to Purchase, dated July 2, 2025 (as it may be amended or supplemented from time to time, the “Offer to Purchase”), and in the related Letter of Transmittal (as it may be amended or supplemented from time to time, the “Letter of Transmittal” and together with the Offer to Purchase, the “Offer”).

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The Offer to Purchase and the Letter of Transmittal are being mailed to Sage’s stockholders together with this Schedule 14D-9 and are filed as Exhibits (a)(1)(A) and (a)(1)(B) to this Schedule 14D-9, respectively, and are incorporated herein by reference. Copies of certain letters distributed by Supernus in connection with the Offer as well as Supernus’ Summary Advertisement published in The New York Times are filed as Exhibits (a)(1)(C), (a)(1)(D) and (a)(1)(E) to this Schedule 14D-9, respectively, and are incorporated herein by reference.

The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of June 13, 2025 (as it may be amended or supplemented from time to time, the “Merger Agreement”), among Supernus, Purchaser, and Sage. The below summary of the Merger Agreement is qualified in its entirety by the description contained in Section 11 (The Merger Agreement; the CVR Agreement; Other Agreements) of the Offer to Purchase and a copy of the Merger Agreement has been filed as Exhibit (e)(1) to this Schedule 14D-9 and each is incorporated herein by reference. Capitalized terms used but not otherwise defined herein have the meanings ascribed to them in the Merger Agreement.

The Merger Agreement provides, among other things, that if the Offer is consummated, as soon as practicable (and in no event later than one (1) business day) following the consummation of the Offer and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, and in accordance with the relevant provisions of the Delaware General Corporation Law (the “DGCL”) and other applicable Legal Requirements, Purchaser will be merged with and into Sage (the “Merger”), the separate existence of Purchaser will cease and Sage will continue as the surviving corporation in the Merger (the “Surviving Corporation”), becoming a wholly owned subsidiary of Supernus. The Merger will be governed by Section 251(h) of the DGCL and will be effected without a vote of the stockholders of Sage. In the Merger, each Share outstanding immediately prior to the effective time of the Merger (being such date and at such time as the certificate of merger in respect of the Merger has been duly filed with the Secretary of State of the State of Delaware or at such later time and date as may be agreed upon by the parties to the Merger Agreement in writing and specified in the certificate of merger, the “Effective Time”) (other than (i) any Shares held immediately prior to the Effective Time by Sage (or held in Sage’s treasury), (ii) any Shares held immediately prior to the Effective Time by Supernus or Purchaser or any other direct or indirect wholly owned subsidiary of Supernus or Purchaser (including, for the avoidance of doubt, any shares acquired by Purchaser in the Offer), and (iii) Shares held by stockholders of Sage who have properly exercised and perfected their statutory rights of appraisal under Section 262 of the DGCL), which will be converted into the right to receive an amount equal to the Offer Price, without any interest thereon and subject to any withholding of applicable taxes (the “Merger Consideration”).

The Offer, the Merger and the other transactions contemplated by the Merger Agreement are collectively referred to as the “Transactions.”

The Merger Agreement also provides that, at the Effective Time,

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The initial expiration date of the Offer is one minute after 11:59 p.m., Eastern Time, on July 30, 2025, unless extended or earlier terminated as permitted by the Merger Agreement (such date or such subsequent date to which the expiration of the Offer is extended in accordance with the Merger Agreement, the “Expiration Date”).

The Merger Agreement also provides, among other things, that, subject to the terms and conditions of the Merger Agreement, including the satisfaction or waiver of all of the conditions of the Offer in the Merger Agreement, Purchaser shall (i) effective as of the time on which the Offer expires on the Expiration Date (the “Offer Acceptance Time”) irrevocably accept for payment all Shares validly tendered (and not validly withdrawn) pursuant to the Offer and (ii) as promptly as practicable after the Offer Acceptance Time pay for such Shares.

The Merger Agreement includes customary termination provisions for both the Company and Parent and provides that, in connection with the termination of the Merger Agreement under specified circumstances, including termination by Sage in order to enter into an acquisition agreement which the Board of Directors has determined constitutes a superior offer. While Sage is not required to consummate the Transactions and can so terminate the Merger Agreement, Sage will be required to pay Supernus a termination fee of $22,376,056 pursuant to the Merger Agreement.

The foregoing summary of the Transactions and the Merger Agreement is qualified in its entirety by the descriptions contained in the Offer to Purchase, the terms of the Merger Agreement, the CVR Agreement and the Letter of Transmittal.

According to the Offer to Purchase, the principal executive office of each of Supernus and Purchaser is 9715 Key West Avenue, Rockville, Maryland 20850, and the telephone number at such principal office is (301) 838-2500. Information relating to the Offer, including the Offer to Purchase, the Letter of Transmittal and related documents (including the Merger Agreement) and this Schedule 14D-9, can be obtained without charge from the SEC’s website at www.sec.gov, or on the “Investors & Media” section of Sage’s website at https://investor.sagerx.com.

Item 3. Past Contacts, Transactions, Negotiations and Agreements.

Except as set forth or incorporated by reference in this Schedule 14D-9 (including with respect to any material agreements, arrangements or understandings, or any actual or potential conflicts of interest between Sage

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or any of its affiliates, on the one hand, and any of Sage’s executive officers, directors or affiliates, on the other hand, as set forth in Sage’s Definitive Proxy Statement on Schedule 14A (other than information furnished rather than filed), filed with the SEC on April 24, 2025 (the “Proxy Statement”), Sage’s Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on February 11, 2025 (the “Form 10-K”), and other filings and reports that Sage has filed with the SEC, to Sage’s knowledge, as of the date of this Schedule 14D-9, there are no material agreements, arrangements or understandings, or any actual or potential conflicts of interest between (i) Sage or any of its affiliates, on the one hand, and (ii) (A) any of its executive officers, directors or affiliates, or (B) Supernus, Purchaser or any of their respective executive officers, directors or affiliates, on the other hand.

The board of directors (the “Board”) of Sage was aware of all such agreements, arrangements or understandings and any actual or potential conflicts of interest described in this Item 3 and considered them along with other matters as described below in the section captioned “Item 4. The Solicitation or Recommendation—Reasons for Recommendation” during its deliberations of the merits of the Merger Agreement and in determining to make the recommendation set forth in this Schedule 14D-9.

Arrangements between Sage and its Executive Officers, Directors and Affiliates.

In considering the recommendation of the Board to tender Shares in the Offer, stockholders of Sage should be aware that Sage’s executive officers, members of the Board and affiliates may be considered to have interests in the execution and delivery of the Merger Agreement and all of the Transactions, including the Offer and the Merger, that may be different from or in addition to those of stockholders of Sage, generally. The Board was aware of these interests and considered them, among other matters, in reaching its decision to approve the Merger Agreement and the Transactions. As described in more detail below, these interests include:

Outstanding Shares Held by Directors and Executive Officers

As of June 27, 2025, the executive officers and directors of Sage beneficially owned, in the aggregate, 169,281 Shares (excluding Shares issuable upon exercise of Company Options and vesting and settlement of Company RSUs and Company PSUs), representing approximately 0.3% of the then outstanding Shares. If Sage’s executive officers and directors were to tender all 169,281 of these Shares for purchase pursuant to the Offer and those Shares were accepted for purchase and purchased by Purchaser, then the executive officers and directors would receive: an aggregate of (i) $1,438,889 in cash upon the closing of the Merger and (ii) 169,281 CVRs representing the right to receive up to $592,484 in cash, in accordance with the terms and conditions of the CVR Agreement, which cash payment obligation is subject to and contingent upon the Company’s satisfaction of specified milestones described further as described below in the section captioned “—Arrangements with Purchaser, Parent, and their Affiliates—CVR Agreement”.

The following table sets forth (i) the number of Shares beneficially owned as of June 27, 2025, by each of Sage’s executive officers (including Barry Greene, who is also a director of Sage) and non-employee directors (excluding Shares issuable upon the exercise of outstanding Company Options and the vesting and settlement of

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Company RSUs and Company PSUs), and (ii) the aggregate consideration that would be payable for such Shares pursuant to the Offer based on the Offer Price and inclusive of the value of the CVRs.

Treatment of Company Equity Awards

Sage’s non-employee directors hold Company Options. The executive officers of Sage hold Company Options, Company RSUs and Company PSUs. At the Effective Time, all Sage equity awards, including awards held by our non-employee directors and executive officers, that are outstanding immediately prior to the Effective Time will generally be subject to the following treatment:

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The following table sets forth the estimated cash amounts that Sage’s executive officers and non-employee directors are eligible to receive (before deduction of applicable tax withholding) in connection with the Merger for their respective outstanding In the Money Options, Company RSUs and Company PSUs, in each case as of June 27, 2025. Solely for purposes of the table below, we have assumed that (i) the Effective Time will occur on June 27, 2025 and (ii) timely satisfaction of all milestones under the CVR Agreement. Pursuant to the terms of the Merger Agreement, any Company Options for which the exercise price is greater than or equal to the Offer Price will be cancelled without payment of any consideration and therefore have not been included in the table below.

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Treatment of Company ESPP

Pursuant to the Merger Agreement, Sage will take all actions necessary pursuant to the terms of the Sage 2014 Employee Stock Purchase Plan (as amended) (the “Company ESPP”) to: (i) provide that (A) the offering period in effect as of June 13, 2025 will be the final offering period under the Company ESPP (the final offering period, the “Current Offering Period”) and the commencement of any future or additional offering periods will be suspended following June 13, 2025 under the Company ESPP unless and until the Merger Agreement is terminated, (B) there will be no increase in the amount of participants’ payroll deduction elections under the Company ESPP during the Current Offering Period from those in effect as of June 13, 2025 and no participant in the Current Offering Period may make separate non-payroll contributions to the Company ESPP on or following June 13, 2025, except as may be required by applicable Legal Requirements, (C) no individual who is not a participant in the Company ESPP as of as of June 13, 2025 will commence participation in the Company ESPP following June 13, 2025, and (D) each outstanding purchase right issued pursuant to the Company ESPP will be fully exercised on the earlier of the scheduled purchase date for such offering period and the date that is no later than five business days prior to the Effective Time (such date, the “Final Exercise Date”) (with any participant payroll deductions that are not otherwise applied to the purchase of Shares in accordance with the terms and conditions of the Company ESPP, to be returned to the participant as promptly as practicable following the Effective Time but no later than the later of five business days after the Effective Time or the first payroll date after the Effective Time), and (ii) cause the Current Offering Period, to the extent that it would otherwise be outstanding at the Effective Time, to be terminated no later than five business days prior to the Effective Time, and terminate the Company ESPP effective immediately prior to, and contingent upon, the Effective Time. All Shares purchased on the Final Exercise Date will be cancelled at the Effective Time and converted into the right to receive the Merger Consideration in accordance with the terms and conditions of the Merger Agreement.

Executive Severance and Change in Control Agreements

Each executive officer of Sage has entered into a severance and change in control agreement pursuant to which the executive officers are eligible to receive certain payments and benefits in the event of the executive officer’s termination of employment without cause or resignation by the executive officer for good reason (a “Qualifying Termination”). In the event of an executive officer’s Qualifying Termination, other than in connection with a change of control, the executive officer would be eligible to receive 12 months of base salary continuation and 12 months of company-subsidized COBRA continuation, provided that the executive officer executes, and does not revoke, a separation agreement and release and continues to comply with any post-employment restrictive covenants.

Pursuant to the severance and change in control agreements, in the event of an executive officer’s Qualifying Termination within the 12-month period following a change in control (such termination, a “Change in Control Termination”), the executive officer will be eligible to receive a lump-sum cash payment equal to (i) 12 months (in the case of Mr. Greene) and nine months (for all other executive officers) of the executive officer’s base salary, (ii) a pro rata target annual bonus for the year of termination based on the number of days the executive officer worked in that year at the time of termination; and (iii) 12 times the monthly employer health insurance contribution, provided that in each case, the executive officer executes, and does not revoke, a separation agreement and release. In addition, all stock options and other stock-based awards with time-based vesting held by the executive officer will immediately accelerate and become fully exercisable or nonforfeitable as of the date of termination.

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In connection with the Merger, it is expected that Sage will amend each severance and change in control agreement to provide for the following severance enhancements in connection with a Change in Control Termination: (i) for Mr. Greene, increasing his cash severance amount to 18 months of base salary plus target annual bonus and increasing the health continuation benefit payment to 18 times the monthly employer health insurance contribution, (ii) for other executive officers, increasing their cash severance amount to 12 months base salary plus target annual bonus and (iii) increasing the health continuation benefit payment to 12 times the monthly employer health insurance contribution.

The severance and change in control agreements also include a Section 280G “better off” provision, which provides that, if any amount received by the executive officer pursuant to the agreement or otherwise that would be subject to the excise tax imposed by Section 4999 of the U.S. Internal Revenue Code of 1986, as amended (the “Code”), the executive would receive the full amount of the payments and benefits or an amount reduced so that no portion would be subject to the excise tax, whichever would result in the largest payment to the executive on an after-tax basis.

For an estimate of the value of the payments and benefits described above that would be payable to Sage’s executive officers upon an involuntary termination of employment in connection with the Merger (i.e., a Change in Control Termination), see the section below captioned “—Golden Parachute Compensation.”

280G Mitigation Actions

Under the Merger Agreement, Sage may implement strategies before the Effective Time to mitigate the amount of potential “excess parachute payments” for “disqualified individuals” (each as defined in Section 280G of the Code), which in certain cases requires consultation with Supernus. However, no executive officer will be entitled to receive gross-ups or tax reimbursements from Sage with respect to any potential excise taxes.

Employee Benefits

Under the Merger Agreement, among other things, Supernus has agreed that for a period of one year following the Effective Time, Supernus will provide, or cause to be provided, to each employee of Sage or its subsidiaries who is employed by Sage or its subsidiaries as of immediately following the Effective Time and who continues to be actively employed by the Surviving Corporation (as defined in the Merger Agreement) (or any affiliate thereof) during the one-year period (each, a “Continuing Employee”) with (i) a base salary or hourly wage rate that is substantially comparable to the base salary or hourly wage rate provided to the Continuing Employee immediately prior to the Effective Time, (ii) short-term cash incentive compensation opportunities at least as favorable as those provided to similarly-situated employees of Supernus and its subsidiaries and (iii) employee benefits (including severance benefits but excluding equity and long-term incentive compensation) that are, in the aggregate and at a minimum, at least as favorable in the aggregate as the benefits (including severance benefits but excluding equity and long-term incentive compensation) provided to similarly-situated employees of Supernus and its subsidiaries.

For employees of Sage that are not Continuing Employees or who are expected to remain employed for a short period of time following the Effective Time to provide transition assistance, the Merger Agreement provides that these employees will be entitled to receive severance payments and benefits under Sage’s broad-based severance plan.

Potential for Future Arrangements

While, as of the date of this Schedule 14D-9, none of Sage’s current executive officers or directors have entered into any employment or other agreement, arrangement or understanding with Supernus or its affiliates regarding continued service with Supernus or its affiliates after the Effective Time, it is possible that Supernus or its affiliates may enter into employment or other arrangements with Sage’s executive officers or directors in the future.

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Employment Agreements

Sage has entered into letter agreements with each of its current executive officers that provide for “at will” employment with Sage. The letter agreements set forth the applicable executive officer’s salary, annual bonus compensation opportunities, as applicable, equity award grant, as applicable and benefit plan participation eligibility. Each of Sage’s executive officers has also executed Sage’s standard form of agreement concerning loyalty, confidential business information, inventions and post-employment activity.

Golden Parachute Compensation

This section sets forth the information required by Item 402(t) of Regulation S-K regarding the compensation for each of Sage’s named executive officers that is based on, or otherwise relates to, the Transactions. This compensation is referred to as “golden parachute” compensation by the applicable SEC disclosure rules. The amounts set forth in the table are estimates based on multiple assumptions that may or may not actually occur, including assumptions described in this Schedule 14D-9 and in the footnotes to the table. As a result, the actual amounts, if any, that a named executive officer receives may materially differ from the amounts set forth in the table. The table below does not include information for Laura Gault, Kimi Iguchi and Anne Marie Cook who are named executive officers but ceased being employed by Sage and are therefore not entitled to any payments or benefits in connection with the Transactions. Ms. Gault’s employment ended in March 2025, and Ms. Iguchi and Ms. Cook ceased being employed by Sage in October 2024.

Specifically, the table below assumes that (i) the Offer was consummated and the Effective Time occurred on June 27, 2025, (ii) the timely satisfaction of all milestones under the CVR Agreement, (iii) the employment of the named executive officer will be terminated immediately following the Effective Time in a manner entitling such individual to receive severance payments and benefits upon a Change in Control Termination under their severance and change in control agreements, (iv) each named executive officer’s severance and change in control agreement was amended as described above in the section captioned “—Executive Severance and Change in Control Agreements”, (v) the named executive officer timely executes (and does not revoke) a separation agreement and release and complies with any applicable post-termination obligations, (vi) the named executive officer’s base salary rate and target annual bonus opportunity remain unchanged from those that will be in place as of June 27, 2025, (vii) no named executive officer receives any additional grants of equity awards on or prior to the Effective Time and (viii) no named executive officer enters into any new agreement with Sage, any of its affiliates or Supernus or any of its affiliates or is otherwise legally entitled to, prior to the Effective Time, additional compensation or benefits. Pursuant to the terms of the Merger Agreement, any Company Options for which the exercise price is greater than or equal to the Offer Price will be cancelled without payment of any consideration and therefore have not been included in the table below.

The values in the table below do not include the value of payments or benefits that would have been earned, or any amounts associated with equity awards that would vest pursuant to their terms, on or prior to the Effective Time or amounts under contracts, agreements, plans or arrangements to the extent they do not discriminate in scope, terms or operation in favor of the named executive officers and that are available generally to all of Sage’s salaried employees. The values and descriptions also do not reflect withholding taxes that are applicable to any payments set forth in the table and assume that no payments are subject to reduction to the extent required by the terms of any applicable agreement to account for the application of Sections 280G and 4999 of the Code to such payments.

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Indemnification of Directors and Officers; Insurance

Sage has entered into an indemnity agreement (each an “Indemnity Agreement” and collectively, the “Indemnity Agreements”) with each of its executive officers and directors that require it to indemnify such persons against any and all expenses, including judgments, fines or penalties, attorneys’ fees, witness fees and related disbursements and other out-of-pocket costs incurred, in connection with any action, suit, arbitration, alternative dispute resolution mechanism, investigation, inquiry or administrative hearing, whether threatened, pending or completed, to which any such person may be made a party by reason of the fact that such person is or was a director, officer, employee or agent of Sage, provided that such director or officer acted in good faith and in a manner that the director or officer reasonably believed to be in, or not opposed to, Sage’s best interests. The foregoing summary of the Indemnity Agreements is qualified in its entirety by the full text of the Form of Officer Indemnification Agreement, which is filed as Exhibit (e)(4) to this Schedule 14D-9 and is included as Exhibit 10.17 to Sage’s Registration Statement on Form S-1, filed with the SEC on July 8, 2014, and incorporated herein by reference and the Form of Director Indemnification Agreement which is filed as Exhibit (e)(5) to this Schedule 14D-9 and is included as Exhibit 10.17 to Sage’s Registration Statement on Form S-1, filed with the SEC on July 8, 2014, and incorporated herein by reference.

The Merger Agreement provides that, for a period of six years from the Effective Time, all rights to indemnification, advancement of expenses and exculpation by Sage or its subsidiaries existing in favor of the current and former directors and officers of Sage or its subsidiaries as of the date of the Merger Agreement for their acts and omissions occurring at or prior to the Effective Time, including pursuant to Sage’s and its subsidiaries’ organizational documents as in effect of the date of the Merger Agreement, and as provided in the Indemnity Agreements or similar agreements between Sage and such directors and officers, will continue in full force and effect.

The Merger Agreement also provides that, from the Effective Time until the 6th anniversary of the date on which the Effective Time occurs, Supernus shall cause the Surviving Corporation and Sage (together with its subsidiaries) to the fullest extent permitted by applicable Legal Requirements, to indemnify and hold harmless each individual who was as of the date of the Merger Agreement, or who becomes prior to the Effective Time, a director or officer of Sage, its subsidiaries or another entity at the request of Sage or its subsidiaries (the “Indemnified Persons”) against all claims, losses, liabilities, damages, judgments, inquiries, fines and reasonable fees, costs and expenses, including attorneys’ fees and disbursements, incurred by such Indemnified Person as an officer or director of Sage or any of its subsidiaries in connection with any claim, action, suit or proceeding arising out of or pertaining to the fact that such Indemnified Person is or was a director or officer of Sage, its subsidiaries or another entity at the request of Sage or its subsidiaries at or prior to the Effective Time. In the event of any such claim, action, suit or proceeding, Supernus shall cause the Surviving Corporation and Sage (together with its subsidiaries) to pay, in advance of the final disposition of such claim, action, suit or proceeding, any expenses incurred in defense thereof by the Indemnified Person upon receipt of an undertaking by such Indemnified Person to repay such amount if it is ultimately determined that such Indemnified Person is not entitled to be indemnified. Supernus shall cause the Surviving Corporation and Sage (together with its subsidiaries) to reasonably cooperate in the defense of any such matter. Each Indemnified Person’s rights are conditioned on their cooperation with Supernus and its subsidiaries in connection with any claims, matters or items for which indemnification is being sought.

The Merger Agreement also provides that prior to the Effective Time, Sage shall purchase a six-year “tail” directors’ and officers’ insurance policy covering Sage, its subsidiaries, and the Surviving Corporation’s current and former directors and officers who are currently covered by the directors’ and officers’ insurance coverage currently maintained by or the benefit of Sage, its subsidiaries and the Surviving Corporation, with such “tail” to provide

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coverage in an amount not less than the existing coverage and having other terms no less favorable than the existing policy, subject to specified limitations. Sage shall cause its insurers to include “successor in interest” language in the applicable endorsements such that Supernus will be covered by such “tail” insurance as a “successor in interest.”

Section 16 Matters

Pursuant to the Merger Agreement, Sage and the Board will take appropriate actions, to the extent necessary, prior to or as of the Offer Acceptance Time, to approve, for purposes of Section 16(b) of the Exchange Act, the disposition and cancellation or deemed disposition and cancellation of Shares and each Company Option, Company RSU and Company PSU in the Merger by any officer or director of Sage who is subject to Section 16 of the Exchange Act intended to cause such dispositions and/or cancellations to be exempt under Rule 16b-3 promulgated under the Exchange Act.

Rule 14d-10 Matters

The Merger Agreement provides that prior to the Offer Acceptance Time and to the extent permitted by applicable Legal Requirements, the compensation committee of the Board will approve, as an “employment compensation, severance or other employee benefit arrangement” within the meaning of Rule 14d-10(d)(2) under the Exchange Act, each agreement, arrangement or understanding between Sage or any of its affiliates and any of the officers, directors or employees of Sage that are effective as of the date of the Merger Agreement pursuant to which compensation is paid to such officer, director or employee and will take all other action reasonably necessary to satisfy the requirements of the non-exclusive safe harbor set forth in Rule 14d-10(d)(2) under the Exchange Act. As of the date of this Schedule 14D-9, the compensation committee of the Board has so approved by unanimous resolution.

Arrangements with Purchaser, Parent, and their Affiliates.

Merger Agreement

On June 13, 2025, Sage, Supernus and Purchaser entered into the Merger Agreement. The summary of the material provisions of the Merger Agreement contained in Section 11 (The Merger Agreement; the CVR Agreement; Other Agreements) and the description of the conditions to the Offer contained in Section 15 (Conditions of the Offer) of the Offer to Purchase are incorporated herein by reference. Such summary and description are qualified in their entirety by reference to the Merger Agreement, which is filed as Exhibit (e)(1) to this Schedule 14D-9 and is incorporated herein by reference.

The Merger Agreement has been filed as an exhibit herein to provide stockholders of Sage with information regarding its terms and is not intended to modify or supplement any rights of the parties under the Merger Agreement. The Merger Agreement and the summary of its terms contained in the Offer to Purchase filed by Purchaser with the SEC on July 2, 2025 are incorporated herein by reference and are not intended to provide any other factual information about Sage, Supernus, Purchaser or their respective subsidiaries and affiliates. The Merger Agreement contains representations and warranties that the parties to the Merger Agreement made to, and solely for the benefit of, each other. The assertions embodied in the representations and warranties contained in the Merger Agreement are qualified by information in confidential disclosure schedules delivered by Sage to Supernus in connection with the signing of the Merger Agreement. Moreover, certain representations and warranties in the Merger Agreement were made as of a specified date, may be subject to a contractual standard of materiality different from what might be viewed as material to stockholders, or may have been used for the purpose of allocating risk between the parties to the Merger Agreement. Accordingly, the representations and warranties in the Merger Agreement should not be relied on by any person as characterizations of the actual state of facts and circumstances of Sage at the time they were made and the information in the Merger Agreement should be considered in conjunction with the entirety of the factual disclosure about Sage, Supernus or Purchaser made in the Schedule TO and related exhibits, including the Offer to Purchase, this Schedule 14D-9, or other public reports filed with the SEC. Information concerning the subject matter of the representations and warranties

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may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in parties’ public disclosures. The Merger Agreement should not be read alone, but should instead be read in conjunction with the other information regarding the Offer, the Merger, Sage, Supernus, Purchaser, their respective affiliates and their respective businesses that are contained in, or incorporated by reference into, the Schedule TO and related exhibits, including the Offer to Purchase, and this Schedule 14D-9, as well as in other public filings with the SEC.

Contingent Value Rights Agreement

At or immediately prior to the consummation of the Offer, Supernus and a rights agent mutually agreeable to Supernus and Sage will enter into the Contingent Value Rights Agreement governing the terms of the CVRs in the form attached to the Merger Agreement as Annex III, with such revisions thereto, if any, requested by the rights agent that are not, individually or in the aggregate, detrimental to any CVR holder (the “CVR Agreement”). Each stockholder of Sage will receive one CVR for each Share they hold and Sage equityholders will receive CVRs as described above in the section captioned “—Treatment of Company Equity Awards.” The CVRs are not transferable except under certain limited circumstances, will not be evidenced by a certificate or other instrument and will not be registered or listed for trading. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Supernus, Purchaser, Sage or any of their Affiliates.

Each CVR represents the right to receive (i) $0.50 upon the first commercial sale in Japan after regulatory approval in Japan to a third-party customer of the pharmaceutical product that, as of the date of the CVR Agreement, is marketed in the United States under the name ZURZUVAE and is the subject of the current regulatory filing (including any amended filings based thereon) by Shionogi & Co., Ltd., inclusive of its Affiliates, Sage’s collaboration partner in Japan, for the treatment of Major Depressive Disorder (“MDD”) on or prior to June 30, 2026; (ii) $1.00 upon achievement of Net Sales (as defined in the CVR Agreement) of ZURZUVAE equal to or exceeding $250,000,000 in the United States during a calendar year on or prior to December 31, 2027; (iii) $1.00 upon achievement of Net Sales of ZURZUVAE equal to or exceeding $300,000,000 in the United States during a calendar year on or prior to December 31, 2028; and (iv) $1.00 upon achievement of Net Sales of ZURZUVAE equal to or exceeding $375,000,000 in the United States during a calendar year on or prior to December 31, 2030. If more than one milestone is achieved during any twelve-month period, all milestone payments corresponding to such achieved milestones shall be payable.

There can be no assurance that the milestones will be achieved by their corresponding deadline dates.

The foregoing description of the CVR Agreement and the transactions contemplated thereby does not purport to be complete and is qualified in its entirety by reference to the form of CVR Agreement, which is attached as Annex III to the Merger Agreement, which is filed as Exhibit (e)(1) to this Schedule 14D-9 and which is incorporated herein by reference.

Confidentiality Agreement

Sage and Supernus entered into a confidentiality agreement, dated February 5, 2025 (the “Confidentiality Agreement”), in connection with each party’s consideration of a potential negotiated transaction between the parties. Under the terms of the Confidentiality Agreement, Supernus agreed, subject to certain exceptions, to keep confidential certain proprietary or non-public information relating to Sage, including the existence and subject matter of the discussions and negotiations concerning a potential negotiated transaction between the parties, and to not disclose, in whole or in part, any of the evaluation material it received from Sage to any person without Sage’s prior written consent. Supernus also agreed to abide by a standstill provision which ceased to be effective upon the execution of the Merger Agreement and the announcement of the Transactions. The Confidentiality Agreement provides that, with respect to Evaluation Material that constitutes “Confidential Information” under the Biogen Collaboration Agreement, any provision under the Confidentiality Agreement would be modified and interpreted to comply with Sage’s obligations thereunder.

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The foregoing summary and description of the Confidentiality Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Confidentiality Agreement, a copy of which is filed as Exhibit (e)(2) to this Schedule 14D-9, which is incorporated herein by reference.

Mutual Non-Disclosure Agreement

Sage and Supernus entered into a mutual non-disclosure agreement, dated January 24, 2025 (the “Non-Disclosure Agreement”), in connection with the consideration by Supernus of a possible business relationship with Sage. Under the terms of the Non-Disclosure Agreement, each party agreed, subject to certain exceptions including the ability to make disclosure required by applicable law, to keep confidential certain confidential information or nonpublic information relating to the other for a period lasting up to two years from the date of the Non-Disclosure Agreement. The agreement did not contain a standstill provision for the benefit of Sage. For further discussion, see the below section captioned “Item 4. The Solicitation or Recommendation—Background of the Offer and the Merger.”

The foregoing summary and description of the Non-Disclosure Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Non-Disclosure Agreement, which is filed as Exhibit (e)(3) to this Schedule 14D-9 and is incorporated herein by reference.

Item 4. The Solicitation or Recommendation.

On June 13, 2025, the Board unanimously (i) determined that the Merger Agreement and the Transactions, including the Offer and the Merger, are fair to, and in the best interest of, Sage and its stockholders, (ii) declared it advisable to enter into the Merger Agreement, (iii) approved the execution, delivery and performance by Sage of the Merger Agreement and the consummation of the Transactions, including the Offer and the Merger, (iv) resolved that the Merger will be effected under Section 251(h) of the DGCL, and (v) resolved to recommend that the stockholders of Sage tender their Shares to Purchaser pursuant to the Offer, in each case on the terms and subject to the conditions of the Merger Agreement.

Accordingly, and for the reasons described below in the section captioned “—Reasons for Recommendation”, the Board, on behalf of Sage, unanimously recommends that Sage’s stockholders accept the Offer and tender their Shares to Purchaser pursuant to the Offer.

Background of the Offer and the Merger

The following chronology summarizes the key meetings and events that led to the signing of the Merger Agreement. This chronology does not purport to catalogue every conversation of or among members of the Board, Sage’s representatives, Supernus, Supernus’s representatives and other parties.

As is customary in the biopharmaceutical industry and with the support of the Board, Sage management regularly meets with other biotechnology and pharmaceutical companies regarding a variety of potential licensing arrangements, joint ventures, collaborations and other strategic transactions. The Board also periodically evaluates Sage’s historical performance, future growth prospects, and long-term strategic plan, and considers various strategic opportunities available to Sage as well as ways to enhance shareholder value, particularly in light of the business, competitive, regulatory, financing, and economic environment and development factors in Sage’s industry. These reviews have included discussions as to whether Sage should continue to execute on its strategy as a stand-alone company, pursue various partnerships, collaborations, or licensing arrangements regarding its pipeline candidates, seek to raise additional capital, including through the sale of additional Shares as well as royalty monetization transactions, or pursue a sale of specific pipeline programs or of the company in its entirety.

On July 23, 2014, Sage completed its initial public offering.

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On June 12, 2018, Sage and Shionogi & Co. Ltd. (“Shionogi”) entered into a Collaboration and License Agreement (the “Shionogi Collaboration Agreement”) for the clinical development and commercialization of Sage’s product candidate zuranolone for the treatment of MDD and other potential indications in Japan, Taiwan and South Korea.

On November 27, 2020, Sage entered into a Collaboration and Licensing Agreement (the “Biogen Collaboration Agreement”) with Biogen MA Inc. (“BIMA”) and Biogen International GMBH (together, the “Biogen Collaboration Parties”) for the development and commercialization of zuranolone and another product candidate. In connection with the entry into the Biogen Collaboration Agreement, on November 27, 2020, Sage and BIMA entered into a stock purchase agreement (the “Biogen Stock Purchase Agreement”) for the sale and issuance of 6,241,473 Shares to BIMA for an aggregate purchase price of $650.0 million. These shares were issued to BIMA on December 31, 2020, and resulted in BIMA owning approximately 10.7 percent of the outstanding Shares. In connection with the issuance of these Shares, Biogen Inc. (“Biogen”) and BIMA filed a Schedule 13G with the SEC. Following entry into the Biogen Collaboration Agreement, representatives of Sage and Biogen frequently spoke regarding matters relating to the collaboration and their plans for zuranolone.

On May 2, 2022, Sage and Biogen announced that they had initiated a rolling submission of a New Drug Application to the U.S. Food and Drug Administration (“FDA”) for zuranolone in the treatment of MDD. Sage and Biogen announced that they expected to submit an associated New Drug Application filing for zuranolone in the treatment of postpartum depression (“PPD”) in the first half of 2023.

On December 6, 2022, Sage and Biogen announced that they had completed the rolling submission of the New Drug Application to the FDA for zuranolone in the treatment of MDD and PPD.

On February 6, 2023, Sage and Biogen announced that the FDA had accepted the filing of the New Drug Application for zuranolone in the treatment of MDD and PPD, the application had been granted priority review, and the FDA had assigned a Prescription Drug User Fee Act action date of August 5, 2023.

On August 4, 2023, the FDA approved ZURZUVAE^® (zuranolone) for the treatment of PPD in adults. The FDA also issued a Complete Response Letter for the New Drug Application for zuranolone in the treatment of adults with MDD, which stated that the application did not provide substantial evidence of effectiveness to support the approval of zuranolone for the treatment of MDD and that an additional study or studies would be needed.

Following the close of trading on August 4, 2023, Sage announced the FDA approval of ZURZUVAE in PPD and the Complete Response Letter for the New Drug Application for zuranolone in MDD. Sage’s stock closed at $36.10 on August 4, 2023, and opened on the next trading day at $18.80.

In December 2023, ZURZUVAE became commercially available for the treatment of PPD in adults in the United States.

Throughout 2024 and into early 2025, Sage engaged with approximately 43 counterparties on potential partnering or financing transactions.

On January 9, 2024, Bryan Roecklein, SVP, Corporate Development of Supernus and Jeff Kasten, VP, Corporate Strategy & Business Development of Sage had a non-confidential meeting to discuss dalzanemdor (SAGE-718), a product candidate that was under investigation for the treatment of patients with mild cognitive impairment or mild dementia due to Alzheimer’s disease, mild cognitive impairment in Parkinson’s disease, and cognitive impairment associated with Huntington’s disease. During this discussion Mr. Roecklein suggested that Supernus might have interest in ZURZUVAE, rather than SAGE-718. On January 29, 2024, Supernus declined to proceed with further discussions with Sage.

On February 16, 2024, the Board reconstituted the previously-formed Transaction Committee, and appointed Elizabeth Barrett, James Frates, Geno Germano, and George Golumbeski to the Transaction Committee. The

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Transaction Committee was expected to review ongoing potential business development activities, with the understanding that the Board would ultimately approve any significant transactions.

In early June 2024, following alignment with the Transaction Committee, Sage submitted a non-binding term sheet to Biogen which contemplated that Biogen would exercise its opt-out rights under the Biogen Collaboration Agreement with respect to zuranolone, which would result in Sage reacquiring its rights to ZURZUVAE, in exchange for Sage paying Biogen royalties and milestone payments, including a royalty in the low twenties percent on net sales of ZURZUVAE in the United States and a royalty in the high single digits percent on net sales of zuranolone outside the United States. Biogen did not engage with Sage to negotiate this proposal by Sage.

On August 9, 2024, a representative of Moelis & Company, Supernus’s financial advisor (“Moelis”), on behalf of Supernus, emailed Barry Greene, Chief Executive Officer of Sage, indicating that Supernus was interested in learning more about Sage and suggesting that Mr. Greene meet with Jack Khattar, Chief Executive Officer of Supernus, to further discuss Sage.

On September 12, 2024, Mr. Greene and Mr. Khattar spoke. During this conversation, Mr. Khattar expressed interest in a potential strategic transaction with Sage, including exploring overall synergies between Sage and Supernus. Mr. Khattar indicated that Supernus could be interested in a whole company acquisition, but no financial terms were discussed.

On September 25, 2024, and September 26, 2024, the Board held a regularly scheduled quarterly meeting, which was also attended by Sage management, representatives of Wilmer Cutler Pickering Hale and Dorr LLP (“WilmerHale”), Sage’s regular corporate counsel and on September 26, 2024, representatives of Goldman Sachs & Co. LLC (“Goldman Sachs”). On September 25, 2024, the Board evaluated Sage’s management’s long-range plan and financial profile. As part of this evaluation, Sage’s management reviewed various cases in the scenario where SAGE-718 was discontinued. Among these cases, Sage’s management reviewed a scenario where Sage discontinued its pipeline and focused on the commercialization of ZURZUVAE (the “September 2024 ZURZUVAE Only Projections”). Sage’s management also presented an internal forecast and assessment of the market potential for ZURZUVAE in PPD based on assumptions of a higher level of investment (the “September 2024 Elevate Projections”). The September 2024 ZURZUVAE Only Projections and the September 2024 Elevate Projections are discussed further in the section below captioned “ —Certain Financial Projections.” During this meeting, Mr. Greene noted to the Board that Supernus was interested in a potential strategic transaction. Additionally, Sage’s management indicated that in the event that SAGE-718 was discontinued, Sage would initiate a restructuring.

On September 26, 2024, representatives of Goldman Sachs reviewed with the Board certain potential strategic alternatives for Sage in the event that SAGE-718 was discontinued, including a potential sale of Sage, a merger of equals with a similarly sized counterparty, a monetization of ZURZUVAE through a royalty financing transaction, an in-license transaction to augment or replace Sage’s pipeline, and a potential restructuring to further streamline Sage’s operations. The Board determined to formally retain Goldman Sachs as Sage’s financial advisor to continue to evaluate potential paths for optimizing Sage’s business and value.

On September 27, 2024, Shionogi announced that it had submitted a New Drug Application in Japan for zuranolone in the treatment of MDD.

On September 30, 2024, Sage entered into an engagement letter with Goldman Sachs pursuant to which Goldman Sachs would advise Sage in connection with Sage’s analysis and consideration of potential strategic alternatives. Pursuant to this engagement letter, if Sage decided to undertake any of the strategic alternatives covered by the engagement letter, and Goldman Sachs agreed to act as financial advisor in connection with such transaction, Sage and Goldman Sachs would enter into an appropriate form of agreement relating to the type of transaction involved and containing customary terms and conditions, including customary fee provisions.

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During the fourth quarter of 2024, Sage actively explored a potential royalty financing transaction. Sage met with nine potential royalty financing counterparties and received two non-binding term sheets for royalty financing proposals. The more favorable of the two, submitted by a global pharmaceutical royalty monetization company (the “Lead Royalty Financing Counterparty”), contemplated an aggregate of $195 million in committed capital, with $130 million upfront and $65 million (which the Lead Royalty Financing counterparty subsequently indicated they would increase to $70 million) in two tranches based on ZURZUVAE net sales milestones in exchange for a 4.5% royalty on U.S. net sales of ZURZUVAE up to $900 million, and a 1.0% royalty on U.S. net sales of ZURZUVAE in excess of $900 million. The non-binding term sheet was conditioned on completion of further due diligence.

On October 8, 2024, Sage announced topline results from the LIGHTWAVE Study evaluating SAGE-718 in participants with mild cognitive impairment or mild dementia due to Alzheimer’s disease. The LIGHTWAVE Study did not demonstrate a statistically significant difference from baseline in participants treated with SAGE-718 versus placebo. As a result, Sage announced that it would be discontinuing further development of SAGE-718 in Alzheimer’s disease.

On October 17, 2024, Sage announced a strategic reorganization of its business operations to support the ongoing launch of ZURZUVAE in PPD and focus pipeline development efforts ahead of a clinical study readout for SAGE-718 in Huntington’s Disease expected later in 2024.

On October 29, 2024, in connection with announcing its third quarter 2024 financial results, Sage announced that it and Biogen would not pursue further development of zuranolone in MDD.

On November 20, 2024, Sage announced topline results from the DIMENSION Study evaluating SAGE-718 in participants with cognitive impairment associated with Huntington’s disease. The DIMENSION Study did not meet its primary endpoint. As a result, Sage announced that it would be discontinuing further development of SAGE-718.

On December 9, 2024, Mr. Greene and Christopher Viehbacher, Chief Executive Officer of Biogen, had a regularly scheduled meeting to discuss ongoing ZURZUVAE commercialization matters. During this meeting, Mr. Viehbacher raised the possibility of Biogen making an offer to acquire Sage. Financial terms were not discussed.

On December 13, 2024, Mr. Khattar emailed Mr. Greene to follow up on their September 12th conversation. Mr. Khattar and Mr. Greene tentatively agreed to speak again following the J.P. Morgan Healthcare Conference in mid-January 2025.

Commencing in December 2024, Sage was contacted from time to time by various stockholders purporting to have recently acquired stakes in Sage and expressing an interest in meeting with Sage to better understand its business, prospects, cost structure and evaluation of strategic alternatives. Sage engaged in discussions with a number of these stockholders based on publicly available information in the months leading up to the announcement of the Transaction, and no confidentiality agreements were entered into. The Board was kept informed on the interactions with these stockholders and the views expressed by these stockholders to Sage management.

On December 16, 2024, the Compensation Committee of the Board had a meeting, which was also attended by Sage management and representatives of Sage’s external compensation consultant. During the meeting, the committee was provided with a proposal from Sage’s management team, which had been developed with Sage’s external compensation consultant, to enhance Sage’s severance and change in control policies for the members of Sage’s management team.

On December 18, 2024, the Board held a regularly scheduled quarterly meeting which was also attended by Sage management and representatives of WilmerHale. Portions of the meeting were also attended by

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representatives of Goldman Sachs, representatives of TD Cowen (“TD Cowen”), which had been engaged by Sage to assist it with evaluating potential royalty financing transactions, and representatives of Joele Frank Wilkinson Brimmer Katcher (“Joele Frank”), Sage’s public relations advisor. During the meeting, Mr. Greene updated the Board on his recent meeting with Mr. Viehbacher and noted that Mr. Viehbacher had raised the possibility of Biogen making an offer to acquire Sage. Sage’s management also discussed the ongoing financial analysis being performed by Sage’s management with the assistance of Goldman Sachs on Sage’s strategic direction, including evaluating potential approaches for Sage to seek to reacquire its rights to ZURZUVAE from Biogen – a transaction that could only be implemented with Biogen’s consent. The Board also received an update from Sage’s management team and TD Cowen on Sage’s ongoing efforts to explore a royalty monetization transaction, including summaries of the two non-binding term sheets for royalty financing proposals that Sage had received in the fourth quarter of 2024 and the status of discussions with the Lead Royalty Financing Counterparty. Management noted for the Board that advancing a royalty monetization transaction would require cooperation from Biogen to share diligence information and to grant a security interest in ZURZUVAE to a counterparty. The Board determined that Sage’s management should continue to explore a potential royalty monetization transaction and engage the Transaction Committee going forward as discussions progressed.

On December 20, 2024, Mr. Viehbacher called Mr. Greene and conveyed Biogen’s interest in making an offer to acquire Sage at the current stock price plus a premium of 30%. Mr. Greene responded that the offer was not acceptable to Sage, but that Mr. Greene would contact key Board members and that if his position changed, he would contact Mr. Viehbacher. Following this conversation, Mr. Greene spoke with Geno Germano, the Chair of the Board, and together they agreed that Biogen’s offer was unacceptable and no immediate Board action was required. Biogen did not submit a proposal at this time. Sage’s stock closed at $5.61 on December 20, 2024.

On January 3, 2025, Sage’s management team notified the Transaction Committee that it had reached alignment on a non-binding term sheet with the Lead Royalty Financing Counterparty that contemplated an aggregate of $200 million in committed capital, with $130 million upfront and $70 million in two tranches based on ZURZUVAE net sales milestones, in exchange for a 4.5% royalty on U.S. net sales of ZURZUVAE up to $900 million (so long as Sage granted a security interest in ZURZUVAE by December 31, 2025, or else a 5% royalty), and a 1.0% royalty on U.S. net sales of ZURZUVAE in excess of $900 million.

On January 9, 2025, Mr. Greene called Mr. Viehbacher at Mr. Viehbacher’s request. During this conversation, Mr. Viehbacher indicated that Biogen was planning to convert its existing Schedule 13G to a Schedule 13D and to attach a proposal to acquire Sage as an exhibit to the Schedule 13D. Mr. Greene noted his belief that public disclosure of the proposal was a violation of the standstill provision in the Biogen Stock Purchase Agreement, which prohibited BIMA from making, or causing any of its affiliates to make, a public acquisition proposal of Sage, but permitted BIMA and its affiliates to have private discussions with Sage and submit confidential proposals that were not reasonably expected to require public disclosure. Mr. Viehbacher subsequently reiterated Biogen’s intention to publicly disclose the forthcoming proposal.

Mr. Greene emailed Mr. Viehbacher later that day to remind Mr. Viehbacher of the standstill obligations under the Biogen Stock Purchase Agreement.

On the afternoon of January 10, 2025, Mr. Viehbacher sent an email to Mr. Greene containing a non-binding proposal to acquire all of the outstanding Shares that are not owned by Biogen or its subsidiaries for a purchase price of $7.22 per Share in cash (the “Biogen January 10 Proposal”), a 30% premium to that day’s closing price of $5.55.

Following the closing of trading on the evening of January 10, 2025, Biogen filed a Schedule 13D which contained a copy of the Biogen January 10 Proposal.

That same day, following the filing of Biogen’s Schedule 13D, Sage issued a press release confirming that Biogen had submitted the Biogen January 10 Proposal and that the Biogen January 10 Proposal would be reviewed and evaluated by the Board.

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As of Sage’s receipt of the Biogen January 10 Proposal, Sage’s management was continuing to evaluate a partnering transaction that had resulted in the receipt of a non-binding proposal. This proposal was initially proposed in 2024 by a healthcare investment firm (the “Partnering Counterparty”) and contemplated that Sage would contribute SAGE-121, a pre-clinical candidate, to a newly formed company that would be funded by the Partnering Counterparty. None of the other potential partnering counterparties contacted by Sage in 2024 and 2025 prior to Sage’s receipt of the Biogen January 10 Proposal were engaged with Sage on a material non-binding proposal for a potential transaction as of January 10, 2025, and except as described herein, none of them engaged with Sage on a material non-binding proposal for a potential partnering transaction prior to the execution of the Merger Agreement on June 13, 2025. Sage continued to internally evaluate a potential transaction with the Partnering Counterparty until the execution of the Merger Agreement on June 13, 2025. The final term sheet submitted by the Partnering Counterparty in February 2025 contemplated that Sage would be issued equity that, following an initial investment round by the Partnering Counterparty, would result in Sage owning 20% of the newly-formed company, and that Sage would be entitled to a $2 million upfront payment, anti-dilution protection on up to $30 million of new equity raises, $169.5 million in development, regulatory, and commercial milestone payments, and a tiered royalty on net sales ranging from 3% to 5%. In March 2025, Sage proposed a counteroffer which included a $6 million upfront payment, anti-dilution protection on up to $35 million of new equity raises, $416 million in development, regulatory, and commercial milestone payments, and a tiered royalty on net sales ranging from 3% to 5%.

On January 12, 2025, the Board held a meeting, which was also attended by Sage management and representatives of WilmerHale, Goldman Sachs and Joele Frank. During the meeting, Mr. Greene and representatives of Goldman Sachs reviewed the Biogen January 10 Proposal, including a timeline of events. Mr. Greene notified the Board that he had explained to Mr. Viehbacher that he believed that a public disclosure of the Biogen January 10 Proposal was a violation of the standstill provision in the Biogen Stock Purchase Agreement. Representatives of Goldman Sachs provided a summary of key terms and a preliminary financial analysis of the Biogen January 10 Proposal. Representatives of WilmerHale offered legal perspectives on the Biogen January 10 Proposal, including reviewing the Board’s fiduciary duties in connection with its consideration of the Biogen January 10 Proposal. The Board discussed initiating litigation to enforce the standstill provision in the Biogen Stock Purchase Agreement and confirmed alignment with management on next steps. Representatives of Goldman Sachs then reviewed an illustrative list of potential counterparties if the Board determined to seek a strategic transaction. The Board agreed that it would meet following the J.P. Morgan Healthcare Conference to further consider the Biogen January 10 Proposal.

On January 16, 2025, Sage commenced litigation against Biogen and BIMA, in the Delaware Court of Chancery seeking declaratory, injunctive and other relief (the “Standstill Litigation”). In its complaint, Sage alleged that Biogen breached the standstill provision in the Biogen Stock Purchase Agreement by making the Biogen January 10 Proposal and related public disclosures. Sage also sought a temporary restraining order enjoining Biogen and BIMA from future breaches of the standstill provision.

On January 22, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, Arps, Slate, Meagher and Flom LLP (“Skadden”), Sage’s outside M&A counsel and litigation counsel in connection with the Standstill Litigation, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene and Chris Benecchi, Chief Operating Officer of Sage, discussed feedback they received from investors at the J.P. Morgan Healthcare Conference, including that several investors thought Sage should sell the company to Biogen or others but at a better price and that others expressed a desire for Sage to reacquire its rights to ZURZUVAE from Biogen. Mr. Shiferman updated the Board on the Standstill Litigation. Representatives of Skadden discussed with the Board its fiduciary duties in connection with the receipt of the Biogen January 10 Proposal. Mr. Benecchi provided an overview of the work performed by Sage’s management with respect to the analysis of the Biogen January 10 Proposal. Representatives of Goldman Sachs then reviewed its preliminary financial analysis of the Biogen January 10 Proposal using three potential long-range forecasts prepared by Sage’s management using a range of peak ZURZUVAE net sales assumptions, which projections are discussed further in the section below captioned “—Certain Financial Projections.” Representatives of Goldman

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Sachs discussed with the Board potential strategic alternatives for Sage, including continuing to promote ZURZUVAE in collaboration with Biogen while continuing pipeline development, repurchasing ZURZUVAE rights from Biogen, exercising Sage’s rights to opt out of the Biogen Collaboration Agreement (which would convert the 50-50 profit-sharing collaboration into an ongoing royalty payable by Biogen to Sage), and potential transactions with other strategic counterparties. Following discussion, the Board determined to (i) reject the Biogen January 10 Proposal, (ii) publicly announce the rejection of the Biogen January 10 Proposal and Sage’s initiation of a review of strategic alternatives, and (iii) seek competitive bids from strategic counterparties and a potential stronger bid from Biogen, while continuing to evaluate a reacquisition of the rights to ZURZUVAE, among other strategic alternatives. During this meeting, the Board also determined that given Sage’s near-term strategic priorities, Sage’s efforts to explore a royalty monetization transaction (which would have required due diligence cooperation from Biogen and was expected to involve the creation of liens that would have required consent from the Biogen Collaboration Parties under the Biogen Collaboration Agreement) should be paused and restarted at a later time, if appropriate.

On January 24, 2025, in preparation for a call between Mr. Greene and Mr. Khattar scheduled for early the following week, Sage and Supernus executed Sage’s standard business development confidentiality agreement. The confidentiality agreement did not include a standstill provision.

On the morning of January 27, 2025, Sage issued a press release and filed a Current Report on Form 8-K with the SEC announcing the initiation of a process to explore strategic alternatives for Sage, including but not limited to a potential strategic transaction, business combination, or sale. Sage also announced that the Board had unanimously rejected the Biogen January 10 Proposal.

Following the announcement of the strategic alternatives process, at the direction of the Board, between January 27, 2025, and February 4, 2025, representatives of Sage and Goldman Sachs contacted 15 potential counterparties, including Supernus, Party A, a global pharmaceutical company, Party B, an American pharmaceutical company, and Party C, a global pharmaceutical company, to discuss their interest in a potential strategic transaction involving Sage. As described further below, 7 of those counterparties, including Supernus (which entered into a new confidentiality agreement with Sage on February 5, 2025), Party A, Party B, and Party C entered into confidentiality agreements with Sage in connection with the strategic alternatives process, each of which included a standstill provision which ceased to be effective upon the execution of the Merger Agreement and the announcement of the Transactions. As described further below, between February 5, 2025, and February 14, 2025, each of these 7 counterparties received a management presentation containing non-public information from Sage.

Also following Sage’s announcement of its strategic alternatives process and through the execution of the Merger Agreement on June 13, 2025, Sage received outreach from a number of its stockholders who were critical of Sage’s cash utilization and encouraged Sage to pursue a sale of the company, an opt-out of Sage’s rights under the Biogen Collaboration Agreement (which would convert the 50-50 profit-sharing collaboration into an ongoing royalty payable by Biogen to Sage), and/or cost-cutting measures, including reduction or elimination of research and development activities. As Sage’s strategic alternatives process progressed, certain stockholders also wrote to the Board expressing frustration with the length of time the process was taking given Sage’s continued cash utilization.

Later on January 27, 2025, Mr. Greene and Mr. Khattar had a call to discuss Supernus’s continued interest in a strategic transaction between Sage and Supernus. No financial terms or timelines were discussed. Mr. Greene suggested that if Mr. Khattar was interested, his team should contact Goldman Sachs.

On January 28, 2025, the Delaware Court of Chancery granted Sage’s motion for a temporary restraining order against BIMA in the Standstill Litigation in order to prevent further breaches of the standstill provision in the Biogen Stock Purchase Agreement.

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On January 29, 2025, representatives of Sage met with a stockholder of Sage as part of ongoing investor relations contact, and the stockholder indicated their desire to assist Sage in connection with its strategic alternatives process, including that they could publicly announce a proposal at a higher value than the Biogen January 10 Proposal with the goal of driving up Biogen’s offer. Sage’s management informed this stockholder that it was working with Goldman Sachs and directed them to contact Goldman Sachs to convey their potential interest in participating in the strategic alternatives process.

Later that day on January 29, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Mr. Benecchi and representatives of Goldman Sachs provided an update on Sage’s strategic alternatives process. Mr. Shiferman provided an update on the Standstill Litigation and the temporary restraining order. Representatives of Sage’s management also updated the Board on the discussion earlier that day with the stockholder, who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process. Members of the Board also discussed potentially modeling scenarios where Sage reacquired rights to ZURZUVAE from Biogen and instructed Mr. Greene to work with Sage’s management to further explore the additional scenarios as part of their ongoing review of strategic alternatives, noting that the additional scenarios depended on significant assumptions such as the ability to reacquire rights to ZURZUVAE from Biogen, the terms of such a transaction, and potential partnership opportunities with third parties. In a closed session, representatives of Sage’s human resources team discussed proposed amendments to Sage’s severance and change in control agreements to enhance Sage’s severance and change in control policies for the members of Sage’s management team, as presented to the Compensation Committee of the Board in December 2024. The members of Sage’s human resources team noted that the intention of this discussion was to obtain Board alignment on the amendment terms but not to seek approval at this time. As part of this discussion, the Board confirmed alignment with the proposed amendment terms.

On January 30, 2025, the Delaware Court of Chancery entered an implementing order for the temporary restraining order against BIMA in the Standstill Litigation, prohibiting BIMA and its directors, officers, agents, employees, attorneys, representatives, persons in active concert or participation with it, and anyone acting under its direction or control from, without Sage’s written consent, (i) making a public acquisition proposal for Sage, (ii) making a private acquisition proposal for Sage that is reasonably expected to require public disclosure, or (iii) publicly encouraging any acquisition proposal for Sage (the “Biogen TRO Order”).

On January 31, 2025, Sage entered into an engagement letter with Goldman Sachs pursuant to which Goldman Sachs would advise Sage in connection with a potential sale of Sage. In determining to engage Goldman Sachs, the Board considered that Goldman Sachs had extensive relationships throughout, and experience and expertise in, the pharmaceutical industry, including having performed investment banking services in the past for Biogen and other potential acquirors of Sage. The Board also considered Goldman Sachs’ long-standing relationship with and knowledge of Sage, including Goldman Sachs having advised Sage in connection with Sage entering into the Biogen Collaboration Agreement in 2020.

On February 4, 2025, Mr. Greene had a regularly scheduled meeting with Mr. Viehbacher concerning ongoing ZURZUVAE co-commercialization matters. During that discussion, Mr. Viehbacher acknowledged Sage’s rejection of the Biogen January 10 Proposal and indicated that Biogen did not plan to immediately follow up with respect to the Biogen January 10 Proposal.

On February 5, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene provided an update on the conversation he had with Mr. Viehbacher the previous day. Mr. Shiferman provided updates on the Standstill Litigation. Mr. Benecchi and representatives of Goldman Sachs provided an overview of the ongoing strategic alternatives process, including management presentations conducted to-date and feedback received. Representatives from Goldman Sachs also updated the Board on interactions with the stockholder who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process.

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On February 6, 2025, representatives of Sage gave a management presentation to representatives of Supernus. Prior to the presentation on February 5, 2025, Sage made an advance copy of the presentation available to Supernus through a virtual data room.

On February 7, 2025, representatives of Supernus had calls with representatives of Sage and Goldman Sachs, respectively, and expressed Supernus’s interest in participating in Sage’s strategic alternatives process.

On February 10, 2025, representatives of Goldman Sachs had a call with representatives of Moelis, regarding Supernus’s involvement in the strategic alternatives process.

On February 12, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Mr. Shiferman provided an update on the Standstill Litigation, including the status of ongoing discussions between Sage and Biogen to resolve the Standstill Litigation without the need for further litigation. Representatives of Goldman Sachs presented an update on the ongoing strategic alternatives process, including management presentations conducted to-date, feedback received, and upcoming management presentations. As previously requested by the Board, representatives of Goldman Sachs then reviewed its preliminary financial analysis of Sage potentially seeking to repurchase rights to ZURZUVAE from Biogen using various illustrative forecast scenarios prepared by Sage’s management, including a revised version of the September 2024 Elevate Projections (the “February 2025 Elevate Projections”), which is discussed further in the section below captioned “—Certain Financial Projections.”

On February 18, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Moelis regarding Supernus’s involvement in the strategic alternatives process.

On February 19, 2025, a representative of Party A spoke with Mr. Kasten and mentioned that Party A was not interested in participating further in Sage’s strategic alternatives process.

Also on February 19, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Party C regarding its continued involvement in the strategic alternatives process, during which call the representatives of Party C confirmed that they remained interested in pursuing a transaction involving Sage.

Also on February 19, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, representatives of Goldman Sachs updated the Board on interactions with the stockholder who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process, noting this stockholder appeared unlikely to be interested in pursuing an acquisition and unlikely to enter into a confidentiality agreement on terms that Sage had required from other participants in the process. Mr. Shiferman also provided an update on the Standstill Litigation, including the status of ongoing discussions between Sage and Biogen to resolve the Standstill Litigation without the need for further litigation. During this conversation, the Board indicated its alignment in resolving the Standstill Litigation. Representatives of Goldman Sachs then updated the Board on Sage’s strategic alternatives process, including an overview of parties who continued to express interest or had declined to further participate in the strategic alternatives process and the list of parties from whom Goldman Sachs was awaiting a response. Representatives of Goldman Sachs also discussed with the Board proposed next steps, including providing limited data room access to parties who had confirmed interest to keep the process moving forward, and the Board confirmed its alignment with the proposed next steps.

On February 20, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Party B’s financial advisor regarding Party B’s continued involvement in the strategic alternatives process, during which call the representatives of Party B’s financial advisor confirmed that Party B remained interested in pursuing a transaction involving Sage.

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Also on February 20, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Party A in which Party A conveyed concerns over cash requirements associated with ZURZUVAE as the reason for no longer participating in Sage’s strategic alternatives process.

On February 21, 2025, at the instruction of Sage’s management, representatives of Goldman Sachs engaged with the Lead Royalty Financing Counterparty to assess whether it would be interested in providing financing that Sage could deploy as part of a potential offer to reacquire rights to ZURZUVAE from Biogen. The representative of the Lead Royalty Financing Counterparty informed Goldman Sachs that it was likely to only be able to finance such a proposal up to $250 million and would require two seats on the Board in connection with such financing.

On February 24, 2025, Mr. Greene received an email from the Chief Executive Officer of Party A in which Party A conveyed that while they were no longer interested in a whole-company acquisition of Sage, they may be interested in pursuing a transaction outside of Sage’s strategic alternatives process. It was not clear from the email what type of potential transaction or relationship would be proposed by Party A.

On February 25, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, Goldman Sachs, and Joele Frank. During the meeting, the Board was updated on interactions with the stockholder who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process, in particular that the stockholder had not made a determination as to whether or not to move forward in the process by executing a confidentiality agreement. The representatives of Goldman Sachs then discussed their conversation with representatives of Party A on February 20, 2025, and Mr. Greene updated the Board on the email he received from Party A’s Chief Executive Officer on February 24, 2025. The Board instructed Mr. Greene to continue to engage with Party A to further evaluate its interest. Mr. Shiferman also presented an update on the Standstill Litigation, including that Sage and Biogen had aligned on terms to resolve the Standstill Litigation without the need for further litigation, which terms were in alignment with the Board’s prior instruction. The Board confirmed its alignment with proceeding with a resolution of the Standstill Litigation. Representatives of Goldman Sachs then reviewed its preliminary financial analyses of Sage’s potential proposal to repurchase ZURZUVAE from Biogen.

Also on February 25, 2025, Sage provided Supernus, Party B and Party C with access to a preliminary virtual data room containing non-public information regarding Sage.

On February 26, 2025, Mr. Kasten had a conversation with a representative of Party A during which the representative of Party A noted that Party A remained interested in Sage’s pipeline portfolio and any potential ex-US rights to ZURZUVAE but was not interested in commercializing ZURZUVAE in the U.S. Following this conversation and until May 29, 2025, representatives of Sage and Party A regularly spoke regarding the potential for Party A to submit a proposal for a transaction involving either Sage’s pipeline portfolio or ex-US rights to ZURZUVAE. As part of these conversations, Sage’s representatives frequently reminded Party A of Sage’s ongoing strategic alternatives process and the importance of Party A executing quickly if it wished to present a proposal for a potential transaction. Sage’s management regularly updated the Board on the status of these discussions. Party A did not ultimately submit a proposal for a transaction.

Also on February 26, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Party B’s financial advisor regarding the strategic alternatives process.

On February 28, 2025, a representative of Party D, a global pharmaceutical company, contacted a representative of Goldman Sachs to request that Party D be invited to participate in Sage’s strategic alternatives process and inquired about the status of the process.

On March 4, 2025, representatives of Goldman Sachs had a follow-up call with representatives of Party C regarding their continued interest in the strategic alternatives process.

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During this time, following their prior outreach, representatives of Goldman Sachs shared a draft confidentiality agreement with representatives of the stockholder who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process. This stockholder did not respond to the draft confidentiality agreement or further request to participate in the strategic alternatives process.

On March 5, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. At the meeting, Mr. Shiferman provided an update on the final terms of a stipulation, proposed order, and final judgment to be filed later that day to make permanent the Biogen TRO Order without the need for further litigation. Representatives of Goldman Sachs updated the Board that Sage’s draft confidentiality agreement had been shared with the stockholder who had been referred to Goldman Sachs to convey their potential interest in participating in the strategic alternatives process, but that the stockholder had not responded. The Board discussed the request from Party D on February 28th to participate in the strategic alternatives process and requested further analysis from management and Goldman Sachs on this topic at the next meeting. Representative of Goldman Sachs then provided updates on Sage’s strategic alternatives process, including an overview of the recent engagement with Supernus, Party B and Party C, during which each party had reaffirmed its interest in a potential strategic transaction involving Sage, the recent conversation with Party A, and the status of ongoing due diligence efforts. The representatives of Goldman Sachs noted that one other company that was contacted by Sage in late January 2025 was still assessing Sage’s fit within its overall strategic priorities, but that each of the 10 other counterparties contacted between late January 2025 and early February 2025 had indicated that they were not interested in a strategic transaction involving Sage. Representatives of Goldman Sachs reviewed with the Board certain potential strategic alternatives available to Sage. Representatives of Goldman Sachs then discussed proposed next steps to advance the strategic alternatives process, including potential timing for ongoing due diligence and requests for bids, and continued discussion of engaging with Party D in response to its outreach.

On March 6, 2025, Sage and Biogen agreed to resolve the Standstill Litigation in the Delaware Court of Chancery, and the Delaware Court of Chancery entered a final permanent injunction to enforce the Biogen TRO Order.

On March 12, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. Representatives from Goldman Sachs discussed with the Board updates on Sage’s strategic alternatives process, including an overview of recent engagement with Supernus, Party B and Party C, and the status of ongoing due diligence with these parties. The Board then discussed the February 28th request from Party D to be invited to participate in Sage’s strategic alternatives process and instructed management and Goldman Sachs to extend this invitation. Representatives of Goldman Sachs then discussed with the Board a certain strategic alternatives that could potentially become available to Sage in light of ongoing discussions with third parties: a whole company sale, a sale of Sage’s pipeline to Party A and simultaneous sale of ZURZUVAE to a third party, Sage continuing to partner on ZURZUVAE with Biogen and entering into a collaboration with Party A, and reacquiring the rights to ZURZUVAE from Biogen and simultaneously entering into a collaboration with Party A.

On March 14, 2025, a representative of Goldman Sachs spoke with a representative of Party D and invited Party D to participate in Sage’s strategic alternatives process and to receive a management presentation from Sage, subject to the execution of a confidentiality agreement. Following this conversation, a draft confidentiality agreement was shared with Party D.

Also on March 14, 2025, Sage responded to a series of initial diligence questions from Supernus.

On March 17, 2025, a representative of Party E, a biotechnology royalty aggregator company, contacted Mr. Greene. The representative of Party E informed Mr. Greene that Party E had been contacted by one of Sage’s stockholders encouraging Party E to participate in Sage’s strategic alternatives process. In subsequent discussions

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with Mr. Greene, the representative of Party E proposed a transaction that would involve the acquisition of Sage, with the potential for a spinoff of a private company holding Sage’s pipeline assets, Sage opting out of its rights to ZURZUVAE under the Biogen Collaboration Agreement (converting the 50-50 profit-sharing collaboration into an ongoing royalty payable by Biogen to Sage), Party E providing Sage’s stockholders with a publicly-traded contingent value right tied to the royalty paid by Biogen, and a distribution of Sage’s net cash to Sage’s stockholders (collectively, the “CVR/Pipeline Spinoff Proposed Transaction”).

Also on March 17, 2025, representatives of Sage gave a management presentation to representatives of Party A.

On March 19, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden and Goldman Sachs. During the meeting, representatives from Goldman Sachs discussed with the Board the status of Sage’s strategic alternatives process and potential timing for the delivery of a process letter to the counterparties that remained interested in a whole company strategic transaction and potential timing for requesting proposals.

On March 20, 2025, a representative of Party B informed Goldman Sachs that it was no longer interested in participating in Sage’s strategic alternatives process.

On March 21, 2025, Party D provided a revised draft of the confidentiality agreement. The parties continued to negotiate the confidentiality agreement and it was subsequently executed on March 26, 2025. The standstill provision by which Party D was bound ceased to be effective upon the announcement of the Transactions.

Also on March 21, 2025, representatives of Goldman Sachs had a call with representatives of Moelis regarding Supernus’s ongoing involvement in the strategic alternatives process.

On March 25, 2025, representatives of Goldman Sachs had a call with representatives of Party C regarding Party C’s ongoing involvement in the strategic alternatives process.

Beginning on March 25, 2025 and through April 12, 2025, Sage provided a series of responses to due diligence requests from Party C.

On March 27, 2025, the Board held its regularly scheduled quarterly meeting, which was attended by representatives of WilmerHale and Sage management and portions of which were also attended by representatives of Skadden and Goldman Sachs. Sage management discussed with the Board financial forecast scenarios, including the January 2025 Budget Projections, the January 2025 Management Projections and the February 2025 Elevate Projections (each of which is defined and described in detail in the section below captioned “ —Certain Financial Projections”). Representatives of Goldman Sachs discussed with the Board updates on Sage’s strategic alternatives process and engagements with Supernus, Party C and Party D, noting that Party B had informed them that it was no longer interested in participating in Sage’s strategic alternatives process. The Board discussed the potential timeline and next steps for the strategic alternatives process, including the timing to deliver process letters to counterparties and timing for the submission of proposals.

Later that day on March 27, 2025, Sage provided Party D with access to a virtual data room containing non-public information regarding Sage.

Also on March 27, 2025, representatives of Goldman Sachs had a call with representatives of Moelis regarding Supernus’s ongoing involvement in the strategic alternatives process.

On March 29, 2025, a member of the board of directors of a private pharmaceutical company contacted a member of the Board to express interest in a potential reverse merger transaction involving Sage.

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On April 1, 2025, at the direction of the Board, representatives of Goldman Sachs sent process letters to both Supernus and Party C requesting that preliminary non-binding written indications of interest for a potential acquisition of Sage be submitted to Goldman Sachs by no later than noon on April 21, 2025.

On April 3, 2025, at the direction of the Board, representatives of Goldman Sachs sent a process letter to Party D requesting that a preliminary non-binding written indication of interest for a potential acquisition of Sage be submitted to Goldman Sachs by no later than noon on April 21, 2025.

Between April 5, 2025 and April 11, 2025, representatives of Goldman Sachs had meetings with Party E to discuss its interest in a potential transaction involving Sage. During the conversation on April 5, 2025, the representatives of Party E reviewed at a high level the CVR/Pipeline Spinoff Proposed Transaction and Party E’s business strategy.

On April 7, 2025, Sage executed a confidentiality agreement specific to Sage’s strategic alternatives process with Party E, which included a standstill provision that ceased to be effective upon the execution of the Merger Agreement and the announcement of the Transactions.

On April 8, 2025, representatives of Goldman Sachs had a call with representatives of Moelis regarding Supernus’s ongoing involvement in the strategic alternatives process.

Between April 8, 2025 and May 14, 2025, Sage responded to various due diligence requests submitted by Party D.

On April 9, 2025, at the direction of the Board, representatives of Goldman Sachs sent a process letter to Party E requesting that a preliminary non-binding written indication of interest for a potential acquisition of Sage be submitted to Goldman Sachs by no later than noon on April 21, 2025.

Also on April 9, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden and Goldman Sachs. During the meeting, representatives from Goldman Sachs provided their perspectives on market dynamics and the potential impact on Sage’s strategic alternatives process. Representatives of Goldman Sachs discussed with the Board the terms of the CVR/Pipeline Spinoff Proposed Transaction and updated the Board on interactions with Party E. The Board requested that Sage and its advisors seek additional clarity on the economic and legal structure aspects of the CVR/Pipeline Spinoff Proposed Transaction. Representatives from Goldman Sachs then discussed with the Board other updates on Sage’s strategic alternatives process. The Board also discussed the initial potential interest conveyed by the private pharmaceutical company to a member of the Board on March 29, 2025 with respect to a potential reverse merger transaction, including that such a transaction was unlikely to be desirable for Sage given the significant funding required to advance the counterparty’s programs and the fact that the private pharmaceutical company had been actively pursuing other reverse merger partners without success to date. After discussion, the Board determined that communications between Mr. Greene and the CEOs of Supernus and Party C, respectively, should be pursued.

On April 10, 2025, representatives of Sage gave a management presentation to representatives of Party E.

On April 11, 2025, Sage provided Party E with access to a virtual data room containing non-public information regarding Sage.

Around this time, Mr. Greene spoke with the Chief Executive Officer of Party E. During this conversation, Party E indicated that it was not likely to include any upfront payment as part of its proposal, but that Party E might be willing to provide some investment into a newly-formed spinoff entity focused on the development of Sage’s pipeline portfolio.

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On April 15, 2025, Mr. Greene and Mr. Khattar spoke regarding Supernus’s ongoing involvement in Sage’s strategic alternatives process. During the conversation, Mr. Khattar inquired about Sage’s ongoing collaboration with Biogen, potential synergies between Sage and Supernus, and potential confirmatory due diligence that Mr. Khattar indicated would be necessary following the April 21st bid deadline. Mr. Khattar further indicated that Supernus was likely to submit a bid on April 21st, subject to confirmatory due diligence. Following this conversation, Mr. Greene emailed Mr. Khattar on April 16, 2025 reiterating that Sage and Supernus could work together to identify synergies and discuss Supernus’s diligence questions after the April 21st bid deadline.

On April 16, 2025, representatives of Goldman Sachs spoke with Party C regarding the upcoming April 21, 2025 bid deadline. During the conversation, Party C informed Goldman Sachs that Party C would not submit a proposal by the April 21st bid deadline. Party C noted its continued interest in an acquisition of ZURZUVAE and its perceived challenges with a whole company acquisition, including the cost of a potential winddown or spinout of Sage’s pipeline product candidates. The representative of Party C indicated that it may submit a ZURZUVAE asset purchase proposal to Sage sometime during the following week, but that such proposal would not be submitted by the April 21st bid deadline.

Also on April 16, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene provided an update on his April 15th phone call with Mr. Khattar. Representatives of Goldman Sachs provided an update on their conversation with Party C, which had taken place just before the Board meeting. Representatives of Goldman Sachs also provided an update on Party D, noting that Party D and its advisors continued to be active in Sage’s virtual data room. Representatives of Goldman Sachs then provided updates with respect to Party E, noting the April 10, 2025 management presentation and recent call between Mr. Greene and the Chief Executive Officer of Party E. Representatives from Goldman Sachs and members of Sage’s management then discussed an alternative approach whereby Sage would exercise its opt-out rights under the Biogen Collaboration Agreement and structure a transaction that was similar to the CVR/Pipeline Spinoff Proposed Transaction, without Party E’s involvement and the corresponding 15% economic leakage to Party E. Representatives of Goldman Sachs and Sage’s management discussed with the Board the potential of pairing a pipeline transaction involving Party A with a ZURZUVAE transaction involving Party E or Party C, depending on the nature of any proposals received on April 21st. Representatives of Goldman Sachs then discussed with the Board various scenarios following the April 21st bid deadline depending on the nature of the bids received, including the potential sequence and timing of counteroffers, the potential for Sage to offer to repurchase ZURZUVAE rights from Biogen, and other alternatives. Representatives of Goldman Sachs then discussed with the Board various considerations related to Sage’s royalty opt-out rights under the Biogen Collaboration Agreement and revisited with the Board prior analysis of a potential repurchase of ZURZUVAE rights from Biogen, including upfront payments, royalties and other financial terms that would need to be formulated in order to make an offer for such a transaction, as well as financing alternatives for Sage in funding such a transaction. The Board discussed that next steps would be driven by the details of any bids received the following week.

On April 16, 2025 and April 17, 2025, representatives of Sage provided responses to certain due diligence requests from Party E.

Also on April 16, 2025, Sage uploaded a capitalization file into the virtual data room, which showed a fully diluted capitalization of Sage as of April 15, 2025, equal to approximately 71 million Shares, including all outstanding options, regardless of exercise price and assuming all performance based restricted stock units vest at their maximum levels of achievement.

On or around April 17, 2025, Sage provided Supernus and Party E with certain financial information, including projected ZURZUVAE revenue for fiscal years 2025 to 2043, described further in the in the section below captioned “ —Certain Financial Projections.”

On April 21, 2025, Mr. Khattar spoke with Mr. Greene ahead of Supernus submitting a non-binding indication of interest to acquire Sage.

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On April 21, 2025, Sage received three non-binding proposals:

Following receipt of the Party D April 21 Proposal and at the direction of Sage’s management, a representative of Goldman Sachs contacted Party D to inform Party D that based on the other offers received, Goldman Sachs expected that, following Board review, Sage was likely to move in a different direction. During this call, the representative of Party D expressed continued interest in remaining in the strategic alternatives process and indicated that Party D could potentially adjust its proposal following receipt of specific guidance.

On April 22, 2025, representatives of Goldman Sachs had a call with representatives of Moelis to discuss the Supernus April 21 Proposal.

On April 23, 2025, representatives of Goldman Sachs had a call with Party C to assess their continued interest in a potential transaction involving ZURZUVAE.

Also on April 23, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, representatives from Goldman Sachs reviewed the terms of the Supernus April 21 Proposal, the Party D April 21 Proposal and

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the Party E April 21 Proposal, including the structure of each offer, proposed timing, upfront and contingent consideration, contingencies, including confirmatory due diligence and the implied enterprise valuation for Sage represented by each offer. Representatives from Goldman Sachs also discussed with the Board Sage’s option to exercise its opt-out rights under the Biogen Collaboration Agreement, without the involvement of Party E or any third party, including the distribution of cash on hand to existing stockholders following an exercise of such opt-out rights and potential options for Sage’s pipeline assets. During the conversation, it was noted that Party D’s current proposal represented the lowest implied enterprise valuation of Sage as compared to all other proposals, and representatives of Goldman Sachs discussed their conversation with representatives of Party D following submission of the Party D April 21 Proposal. Representatives from Goldman Sachs and Skadden also discussed with the Board aspects of the Party E April 21 Proposal that would require further clarification in order to assess potential reductions to the consideration available for Sage’s stockholders and legal constraints that could affect timing for completion, and the Board requested that Sage’s advisors seek further clarification from Party E. The Board discussed next steps with its advisors and authorized representatives of Goldman Sachs to convey a proposed counteroffer to Supernus and Party D involving upfront consideration of at least $10.25 per share and contingent value rights up to an additional $5.00 per share based on milestones tied to approval of zuranolone in Japan for the treatment of MDD, commercial revenue targets for ZURZUVAE in the U.S., and developmental goals associated with Sage’s pipeline product candidates. The Board then further discussed other potential strategic alternatives available to Sage, including the potential to seek to reacquire the rights to ZURZUVAE from Biogen, exercise Sage’s opt-out rights under the Biogen Collaboration Agreement without Party E, and spinout rights to all or some of Sage’s pipeline assets.

On April 25, 2025, at the direction of the Board, representatives of Goldman Sachs shared the terms of a proposed counteroffer with Moelis for the acquisition of all outstanding Shares of Sage for an upfront payment of $10.25 per Share in cash and one contingent value right per Share representing the right to receive $2.00 in cash upon zuranolone regulatory approval in Japan for the treatment of MDD, $1.00 in cash upon total ZURZUVAE U.S. sales exceeding $325 million, $1.00 in cash upon total ZURZUVAE U.S. sales exceeding $450 million and $1.00 in cash upon the initiation of a Phase 2 clinical trial for any of Sage’s pipeline drug candidates (the “Sage April 25 Counteroffer”). The representative of Moelis indicated that Supernus would consider the Sage April 25 Counteroffer. The representative of Goldman Sachs indicated that Sage had received acquisition proposals from other parties and requested that Supernus submit a revised bid by May 5, 2025.

Also on April 25, 2025, at the direction of the Board, representatives of Goldman Sachs shared the Sage April 25 Counteroffer with representatives of Party D. The representative of Party D indicated that it would consider the Sage April 25 Counteroffer. The representative of Party D requested that Sage facilitate more in-depth due diligence regarding topics of importance to Party D. The representative of Goldman Sachs requested that Party D submit a revised bid by May 5, 2025.

During the weekend of April 26 and 27, 2025, representatives of Sage met with representatives of a European pharmaceutical company who expressed interest in Sage’s pipeline candidates but did not indicate how quickly they would be prepared to progress a potential transaction and did not make any specific proposals.

Also on April 28, 2025, Party C submitted a non-binding proposal for the acquisition of all of Sage’s interest in ZURZUVAE for an upfront payment of $200 million and net sales milestones totaling $265 million (the “Party C April 28 Proposal”).

On April 30, 2025, representatives of Goldman Sachs had a follow-up call with Party C to discuss the Party C April 28 Proposal, including the proposed structure, timing expectations and diligence requests.

Also on April 30, 2025, Moelis sent Goldman Sachs a list of due diligence questions and requests on behalf of Supernus. Between April 30, 2025 and the execution of the Merger Agreement on June 13, 2025 and as described further below, Supernus would continue to submit additional due diligence questions and requests and Sage would provide answers and responsive materials. Additionally, during that time and as described further below Sage and Supernus conducted a series of due diligence calls and meetings to discuss various topics.

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On April 30, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene updated the Board on Sage’s first quarter earnings call and the feedback received from investors. Representatives from Goldman Sachs discussed with the Board recent engagement with Supernus, Party D and Party E and noted that the Sage April 25 Counteroffer had been communicated to both Supernus and Party D and that revised bids were requested by May 5, 2025. Representatives of Goldman Sachs then discussed initial responses from both Supernus and Party D following communication of the Sage April 25 Counteroffer, including that Party D had requested more in depth due diligence regarding topics of importance to Party D. Representatives of Goldman Sachs then discussed with the Board the Party C April 28 Proposal, including a comparison of the implied upfront value of the Party C April 28 Proposal to the other proposals received by Sage and to the Sage April 25 Counteroffer. The Board requested that Sage continue to engage with Party C. The Board also discussed the possibility of proposing a buyback of ZURZUVAE rights under the Biogen Collaboration Agreement following the receipt of revised proposals on May 5^th.

On May 1, 2025, representatives of Goldman Sachs had a follow-up call with Party E to discuss the Party E April 21 Proposal, including timing expectations and diligence requests.

On May 1, 2025, Moelis informed Goldman Sachs that Supernus’s acceptance of the Sage April 25 Counteroffer was unlikely, but that Supernus would need additional time beyond May 5, 2025, to provide an informed response to the Sage April 25 Counteroffer.

On May 2, 2025, representatives of Sage held a due diligence call with representatives of Party D to discuss due diligence matters.

On May 2, 2025 and May 3, 2025, representatives of Skadden and Goldman Sachs had conversations with Party E’s outside counsel. During these conversations, representatives of Party E’s outside counsel confirmed that Party E expected the transaction structure would hold back cash otherwise distributable to Sage’s stockholders in an amount sufficient to cover contingent liabilities at Sage, and that further due diligence would be needed for Party E to propose the amount of such a holdback.

On May 4, 2025 and May 5, 2025, Sage provided Supernus and Party D, respectively, with a capitalization file, which showed a fully diluted capitalization of Sage as of April 30, 2025 equal to approximately 71.6 million Shares, including all outstanding options, regardless of exercise price and assuming all performance based restricted stock units vest at their maximum levels of achievement.

On May 5, 2025, Party D submitted a revised non-binding indication of interest to acquire all of the outstanding Shares of Sage for an upfront payment of $9.00 per Share in cash and one contingent value right per Share representing the right to receive $2.00 in cash upon annual net sales of ZURZUVAE in the U.S. in a calendar year first equaling or exceeding $450 million and $2.00 in cash upon annual net sales of ZURZUVAE in the U.S. in a calendar year first equaling or exceeding $700 million (the “Party D May 5 Proposal”). Party D’s non-binding offer continued to indicate that Party D was prepared to work at an expedited pace to reach agreement and would work on a definitive agreement in parallel. The Party D May 5 Proposal indicated an assumed fully diluted share count of approximately 66.6 million Shares.

On May 7, 2025, Mr. Khattar called Mr. Greene to indicate that Supernus would be providing a revised bid. Mr. Khattar provided context for the Supernus bid and indicated that while Supernus appreciated the diligence provided and Sage’s engagement, the terms of the Sage April 25 Counteroffer almost caused Supernus to not re-bid. Mr. Khattar indicated that Supernus was stretching to provide its revised bid and that Supernus would not be able to increase its offer further. Following this call, Supernus submitted a revised non-binding indication of interest to acquire all of the outstanding Shares of Sage for an upfront payment of $8.50 per Share in cash and one contingent value right per Share representing the right to receive $1.00 in cash payable upon Supernus booking annual net sales of ZURZUVAE of $200 million by December 31, 2027, $1.00 in cash payable upon Supernus

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booking annual net sales of ZURZUVAE of $300 million by December 31, 2028, $1.00 in cash payable upon Supernus booking annual net sales of ZURZUVAE of $400 million by December 31, 2030, and $0.50 in cash upon zuranolone regulatory approval in Japan for the treatment of MDD by December 31, 2025 (the “Supernus May 7 Proposal”). The Supernus May 7 Proposal indicated an assumed fully diluted share count of approximately 66.5 million Shares.

On May 7, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, representatives of Goldman Sachs summarized the terms of the Party D May 5 Proposal and the Supernus May 7 Proposal, including proposed upfront consideration and contingent value rights based on various milestones described in each proposal. As part of this discussion, Mr. Greene updated the Board on his call with Mr. Khattar in which Supernus indicated it was not likely to be able to increase its offer beyond the terms in the Supernus May 7 Proposal. Representatives of Goldman Sachs then led a discussion on potential next steps for Party D and Supernus, Representatives of Goldman Sachs also reviewed considerations associated with the other strategic alternatives evaluated by the Board. Representatives from Goldman Sachs and Skadden then discussed the general timeline for a strategic transaction. The Board confirmed its alignment with the proposed messaging and counterproposal to be conveyed to Party D as well as delaying further engagement with Supernus pending feedback from Party D on the counterproposal. As part of these discussions, the Board also discussed potential structures for separating Sage’s pipeline assets in connection with a sale of Sage to a counterparty (if such a separation were acceptable to a counterparty), noting the execution risks and adverse impact to timing. Mr. Greene also discussed risks associated with Sage exercising its opt-out rights under the Biogen Collaboration Agreement.

On May 8, 2025, at the direction of the Board, Goldman Sachs shared the terms of a proposed counteroffer with Party D for the acquisition of all outstanding Shares of Sage for an upfront payment of $9.50 per Share in cash and one contingent value right per Share representing the right to receive $2.00 in cash upon annual net sales of ZURZUVAE in the U.S. in a calendar year first equaling or exceeding $450 million, $2.00 in cash upon annual net sales of ZURZUVAE in the U.S. in a calendar year first equaling or exceeding $700 million, and $0.50 in cash upon zuranolone regulatory approval in Japan for the treatment of MDD (the “Sage May 8 Counteroffer”).

On May 9, 2025, representatives of Sage had a due diligence call with representatives of Party D to further discuss due diligence matters.

Later that day on May 9, 2025, representatives of Party D contacted Goldman Sachs to convey that Party D could potentially reach alignment on the terms of the Sage May 8 Counteroffer, subject to satisfactory completion of due diligence.

On May 10, 2025 and May 11, 2025, representatives of Skadden had calls with Party D’s outside counsel to further discuss due diligence matters.

On May 11, 2025, the Compensation Committee of the Board held a meeting, which was also attended by Sage management and representatives of Skadden. During the meeting, Sage management and representatives of Skadden discussed with the Compensation Committee potential change of control compensation decisions that would need to be addressed in the event Sage could successfully negotiate a transaction with any of the parties remaining in the strategic alternatives process, including proposed amendments to the severance and change in control agreements for members of Sage’s management team, how the performance restricted stock units held by members of Sage’s management team would vest in the event of a change of control, the analysis of the impact of Internal Revenue Code Sections 280G and 4999 on certain payments expected to be made to Sage’s management team members in the event of a change in control (and the cost of a potential gross-up arrangement), and the implementation of a non-executive transaction bonus pool. No determination was made by the Compensation Committee at this meeting related to these matters.

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On May 13, 2025, at the direction of Sage’s management, representatives of Goldman Sachs communicated to both Supernus and Party C that they each needed to increase the price of their prior offers, but that Sage was prepared to allow them to proceed to full diligence on an accelerated pace. The representatives of Supernus indicated a desire to continue proceeding with diligence and were told they would be provided with immediate access to a broader virtual data room containing additional confirmatory materials. The representatives of Party C indicated that they planned to connect internally before reaching out to Goldman Sachs to confirm a desire to proceed with further diligence, and subsequently contacted Goldman Sachs indicating a desire to proceed with further diligence and requesting access to the virtual data room.

That same day, representatives of Party D contacted Goldman Sachs to convey that Party D continued to evaluate due diligence topics of importance to Party D.

On May 14, 2025, as discussed between Goldman Sachs and Supernus, Sage provided Supernus with access to a broader virtual data room containing additional confirmatory materials.

On May 14, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, Goldman Sachs, and Joele Frank. During the meeting, the Board discussed with its advisors updates on interactions with each of Supernus, Party D, Party C and Party E, including that representatives of Party D had confirmed that Party D could potentially reach alignment on the terms of the Sage May 8 Counteroffer, subject to satisfactory completion of due diligence. Sage’s advisors discussed with the Board the ongoing due diligence being conducted by Party D. Representatives of Goldman Sachs then discussed proposed next steps for Supernus, Party C, and Party E, including reviewing options, potential messaging, timing, and key considerations. As part of this discussion, representatives of Goldman Sachs reviewed the terms of the Supernus May 7 Proposal, as compared to the latest proposals from Party D, Party C, and Party E, and discussed potential next steps, pending the outcome of ongoing discussions with Party D. Sage’s management discussed the May 2025 Projections (which is defined and discussed further in the section below captioned “ —Certain Financial Projections”). Representatives of Goldman Sachs then presented analysis based on these projections prepared by Sage’s management. Sage’s management and representatives of Goldman Sachs then discussed with the Board potential standalone alternatives, including one where Sage focused on the commercialization of ZURZUVAE and another where Sage exercised its opt-out rights under the Biogen Collaboration Agreement, without the involvement of Party E or any third party, and distributed cash on hand to existing stockholders. Representatives of Goldman Sachs and management discussed the risks and uncertainties associated with each potential standalone alternative, including risks and uncertainties associated with future capital needs, the winddown of Sage’s pipeline assets, retention challenges, potential reorganization costs, and potential actions that might be pursued by Biogen under each potential standalone alternative for Sage. Representatives of Goldman Sachs then provided additional feedback regarding the latest discussions with Party D and the proposed approach for follow-up with Party D and other counterparties, pending feedback from Party D. The Board confirmed its alignment with the proposed messaging and approach.

On May 15, 2025, representatives of Goldman Sachs and Party D had a call during which the representative of Party D informed Goldman Sachs that it was no longer interested in moving forward in the strategic alternatives process at this time and referenced due diligence matters as having impacted Party D’s decision.

Following this communication by Party D, Sage terminated Party D’s access to the virtual data room and requested that Party D destroy all confidential information shared with it during the strategic alternatives process.

On May 15, 2025, representatives of Goldman Sachs spoke with Party C to discuss the Party C April 28 Proposal. During the conversation, a representative of Goldman Sachs conveyed Sage’s desire that Party C submit a revised proposal prior to the annual stockholders meeting and the representative of Party C indicated that Party C would require approximately 8 weeks of due diligence prior to being able to execute definitive agreements regarding a potential transaction, but that they would try to submit a proposal prior to the annual stockholders meeting.

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Also on May 15, 2025, Mr. Greene spoke with Mr. Khattar to discuss timing and next steps. During the call, Mr. Greene proposed that the Sage management team visit Supernus’s office and conduct a series of in-person meetings with Supernus to help strengthen the relationship and expeditiously finalize due diligence. During this call, Mr. Greene expressed that Sage’s desire was to finalize a transaction that could be announced prior to its annual stockholders meeting on June 11, 2025 and that representatives of Goldman Sachs would follow up with Moelis on the terms of a counterproposal.

On May 16, 2025, at the direction of the Board, representatives of Goldman Sachs spoke with Moelis to discuss the Supernus May 7 Proposal. During the call, representatives of Goldman Sachs discussed with Moelis guidance from the Board that Supernus should seek to increase the Supernus May 7 Proposal to $9.50 per Share in cash upfront and a total of $3.50 per Share in cash in contingent value rights, with longer deadlines to achieve the contingent value right milestones (the “Sage May 16 Counteroffer”) and proposed that Sage and Supernus negotiate the terms of a merger agreement alongside finalizing Supernus’s due diligence.

On May 16, 2025, Mr. Kasten spoke with Mr. Roecklein to align on a series of virtual due diligence meetings during the week of May 19, 2025, followed by in-person meetings that would be scheduled to begin on May 27, 2025. During this call, Mr. Kasten also communicated Sage’s desire to announce a transaction prior to its annual stockholders meeting on June 11, 2025. Following this conversation Mr. Greene and Mr. Khattar exchanged emails on May 17, 2025 to coordinate the in-person meeting.

On May 17, 2025, representatives of Party E asked Goldman Sachs if they should continue to engage in the strategic alternatives process given that Sage had not communicated a desire to move forward with a transaction with Party E.

Later that day on May 17, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden and Goldman Sachs. During the meeting, representatives of Goldman Sachs discussed with the Board their conversations with Party D and Supernus, including their recent call with Moelis during which Goldman Sachs provided the Sage May 16 Counteroffer. Mr. Greene provided an update on his phone call with Mr. Khattar and Mr. Kasten provided an update on his phone call with Mr. Roecklein. Representatives of Goldman Sachs also provided an update on their conversation with representatives of Party C, during which Party C signaled that it would require approximately 8 weeks of due diligence prior to being able to execute definitive agreements regarding a potential transaction. The Board discussed with its advisors prioritizing efforts with Supernus and moving forward with Party C in parallel. Goldman Sachs updated the Board that Party E had indicated to Goldman Sachs that it was no longer actively pursuing a transaction with Sage given that Sage had not communicated a desire to move forward with a transaction with Party E. The Board considered the structure of the Party E April 21 Proposal, including the issues identified following Skadden’s and Goldman Sachs’ conversations with Party E’s outside counsel with respect to reductions to consideration available for Sage’s stockholders and other legal constraints that could affect Sage’s ability to successfully complete the transaction as proposed. Mr. Greene indicated that he planned to call Party E’s Chief Executive Officer to inform them that Sage is moving in another direction.

On the morning of May 19, 2025, Mr. Greene called Party E’s Chief Executive Officer to inform them that Sage was moving in another direction as part of the strategic alternatives process.

On May 19, 2025, Supernus sent Sage a fulsome due diligence request list, which Sage provided responses to on May 22, 2025.

Also on May 19, 2025, Skadden made available to Supernus, Moelis, and Saul Ewing LLP (“Saul Ewing”), Supernus’s legal counsel, a preliminary draft of the merger agreement, accompanying disclosure schedule and contingent value rights agreement. The preliminary draft of the merger agreement contemplated that all equity awards would be fully accelerated and cashed out at closing, with all performance based restricted stock units deemed to vest at their maximum levels of achievement.

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Beginning on May 21, 2025, Sage had a series of meetings with representatives of Supernus to discuss certain due diligence questions regarding Sage, including topics relating to Sage’s research and development pipeline, Sage’s intellectual property and other legal matters, Sage’s capabilities and potential synergies between Sage and Supernus.

On May 21, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Skadden, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Goldman Sachs discussed with the Board the ongoing due diligence activities with Supernus and the fact that the draft merger agreement, disclosure schedule and contingent value rights agreement had been shared with Supernus. Mr. Greene updated the Board on his planned dinner with Mr. Khattar the following day and discussed his proposed approach and objectives for the dinner, including to discuss timing considerations and next steps to advance the process with Supernus. Representatives of Goldman Sachs updated the Board on interactions with Party C, including that Party C continued to remain active in Sage’s virtual data room and that there was a call scheduled for May 30, 2025 to discuss Sage’s collaboration with Biogen. Mr. Benecchi then led a discussion of proposed next steps in the strategic alternatives process, including internal scenario planning depending on the outcome of efforts to reach acceptable transaction terms with Supernus. It was noted that given uncertainty as to whether Supernus would ultimately be willing to proceed with a transaction on terms that were in the best interests of Sage and its stockholders, management continued to evaluate other alternatives to further the Board’s review, in particular a scenario that could include resource reallocation, a winddown of research and development activities, and a workforce reorganization, with the goal of extending Sage’s cash runway and achieving profitability from the ongoing commercialization of ZURZUVAE. Mr. Benecchi noted that Sage was advancing analysis to enable expedient implementation in the event that the Board determined that the reorganization was in the best interests of Sage and its stockholders. Mr. Greene also discussed the perspectives expressed to Sage by certain of its stockholders with respect to potential strategic alternatives. The Board confirmed its alignment with parallel preparation efforts for the reorganization as part of the ongoing strategic alternatives process.

On May 22, 2025, representatives of Goldman Sachs had a follow-up call with Moelis to discuss diligence matters and the potential transaction with Supernus.

Later that evening on May 22, 2025, Mr. Greene and Mr. Khattar met over dinner in New York City. During their meeting, Mr. Greene emphasized the importance to Sage of being able to have clarity on a potential transaction prior to Sage’s annual meeting of stockholders on June 11, 2025. Mr. Greene further noted his perspective that ZURZUVAE has increased potential with further investment beyond the historic levels that had resulted from the joint decision-making process required under the Biogen Collaboration Agreement.

On May 27, 2025, Sage and Supernus conducted an all-day in-person meeting in Rockville, MD to discuss a number of due diligence topics related to commercialization, supply chain, R&D functions, and financials.

Later that evening on May 27, 2025, the Sage and Supernus teams went out to dinner. Mr. Khattar raised a number of specific concerns to Mr. Greene regarding a potential acquisition of Sage.

On May 28, 2025, representatives of Goldman Sachs spoke with representatives of Moelis regarding Supernus’s ongoing due diligence efforts.

Later in the day on May 28, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Kirkland & Ellis LLP (which had been engaged by Sage, in addition to Skadden, following the transition of the lead transactional partners from Skadden to Kirkland in May 2025) (“Kirkland”), WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene updated the Board on the virtual and in-person due diligence meetings held between Sage and Supernus. Mr. Greene also updated the Board on his dinners with Mr. Khattar and discussed with the Board the concerns Mr. Khattar raised during the dinner the previous evening. Representatives of Goldman Sachs also discussed with the Board the feedback they had received from Moelis. Mr. Greene then discussed with the Board that Sage continued to progress parallel

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preparation efforts for a standalone strategic alternative scenario that could include resource reallocation, a winddown of research and development activities, and a workforce reorganization, with the goal of extending Sage’s cash runway and achieving profitability from the ongoing commercialization of ZURZUVAE. Representatives from Goldman Sachs then provided an update with respect to Party C, including proposed next steps to help Party C reach a refined view on value. It was noted that Party C continued to move at a much slower pace than Supernus and that it remained difficult to assess their level of interest in pursuing a potential transaction. Mr. Greene further discussed with the Board his perspectives on the ongoing due diligence being conducted by Supernus and strategies for increasing the likelihood that engagement with Supernus would result in a transaction on terms that were in the best interests of Sage and its stockholders.

On May 29, 2025, and May 30, 2025, representatives of Sage had meetings with representatives of Party C to discuss certain finance due diligence questions and certain due diligence questions regarding Sage’s collaboration with Biogen.

On May 30, 2025, representatives of Goldman Sachs had a follow-up call with Moelis to discuss the potential transaction with Supernus.

On May 31, 2025, Mr. Greene had a call with Mr. Khattar to discuss the potential transaction with Supernus, including the importance of progressing Supernus’s due diligence toward completion. Mr. Greene emphasized the importance of Supernus providing a revised proposal consistent with Sage’s prior guidance, a revised merger agreement and an indication that Supernus had completed its pre-signing due diligence investigation by the end of the day on June 6th.

On June 1, 2025, Sage provided Supernus with a pro forma capitalization file, which showed a fully diluted capitalization of Sage as of June 2, 2025, equal to approximately 71.6 million Shares, including all outstanding options, regardless of exercise price and assuming all performance based restricted stock units vest at their maximum levels of achievement.

On the afternoon of June 3, 2025, representatives of Supernus’s business development team contacted Mr. Kasten identifying a list of due diligence functional meetings that were being requested by Supernus for that week and early the week of June 9th.

On June 3, 2025, in response to the email sent by Supernus’s business development team, representatives of Goldman Sachs called Moelis to discuss the due diligence requests and the impact on timing.

Also on June 3, 2025, in response to the email sent by Supernus’s business development team, Mr. Kasten called Mr. Roecklein to discuss a path forward to meet Sage’s June 6th proposed timing. Mr. Roecklein indicated that Supernus expected to submit a proposal without having completed the requested functional meetings, but that having the functional meetings would be necessary prior to signing. Mr. Roecklein also noted there were concerns that could impact Supernus’s view of valuation.

Also on June 3, 2025, Mr. Greene called Mr. Khattar to discuss the ongoing timing of a potential transaction. During the conversation, Mr. Greene reiterated Sage’s view of the June 6th proposed timing. Mr. Khattar indicated that he continued to feel positive about the possibility of a transaction, but that there remained outstanding diligence concerns. Mr. Khattar indicated that Supernus expected to submit a proposal by June 9th.

On the evening of June 3, 2025, the Compensation Committee of the Board held a meeting, which was also attended by Sage management and representatives of Kirkland and Sage’s external compensation consultant. During the meeting, Sage management discussed with the Compensation Committee potential change of control compensation decisions that would need to be addressed in the event Supernus was willing to proceed with a transaction, including proposed amendments to the severance and change in control agreements for the members of Sage’s management team, how the performance restricted stock units held by members of Sage’s management

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team would vest in the event of a change of control, the analysis of the impact of Internal Revenue Code Sections 280G and 4999 on certain payments expected to be made to Sage’s management team members in the event of a change in control (and the cost of a potential gross-up arrangement), and the implementation of a non-executive transaction bonus pool. Sage management indicated that the goal of the conversation was to provide the Compensation Committee with the data necessary to make a decision if Supernus did ultimately engage on a potential transaction. The Compensation Committee asked that Sage management provide additional information on which performance restricted stock unit vesting conditions would be reasonably likely to be satisfied in the future and which were not reasonably likely to be satisfied in the future, in the absence of a transaction. In addition, the Compensation Committee requested that all of the change of control compensation decisions be addressed by the full Board at an upcoming meeting.

On the morning of June 4, 2025, the Board held a meeting, which was also attended by representatives of Kirkland and Goldman Sachs. During the meeting, the Board discussed potentially implementing a standalone strategic alternative scenario focused on the commercialization of ZURZUVAE, which assumed a resource reallocation, a winddown of research and development activities, and a workforce reorganization, with the goal of extending Sage’s cash runway and achieving profitability from the ongoing commercialization of ZURZUVAE, in the event that a transaction with Supernus was not available on terms that the Board viewed as in the best interests of Sage and its stockholders, or not available at all. Mr. Greene also discussed with the Board recent interactions with Supernus, noting that Supernus was now anticipated to provide an updated proposal on June 6, 2025. Mr. Greene summarized the due diligence concerns raised by Supernus and the efforts on the part of Sage and its advisors to address these concerns. Mr. Greene noted that these concerns could cause Supernus to not agree to the economic terms most recently proposed by Sage in the Sage May 16 Counteroffer or to not bid at all. Representatives of Goldman Sachs noted that Supernus had previously conveyed that the Supernus May 7 Proposal was difficult for Supernus to get to, and that at that time, Mr. Khattar had communicated to Mr. Greene that Supernus would not be able to increase its offer further. Members of the Compensation Committee discussed with the Board the next steps requested by the committee, after its June 3, 2025 meeting with management and advisors, for management to revise its recommendations for compensation matters relevant to a potential transaction with Supernus and to present such matters for review by the Board at an upcoming meeting.

On June 5, 2025, representatives of Goldman Sachs and Moelis spoke. During this conversation, Moelis confirmed that Supernus intended to send a revised proposal on June 6th, which would include a markup of the merger agreement and the contingent value rights agreement.

That same day, Party C sent Sage a further diligence request list.

On June 6, 2025, Mr. Greene spoke to Mr. Khattar ahead of Supernus formally providing an updated non-binding indication of interest to discuss Supernus’s proposal. During the conversation, Mr. Khattar indicated that Supernus was prepared to move quickly but that there were many confirmatory items that Supernus would need before signing. Mr. Greene attempted to further negotiate the terms of the Supernus June 6 Proposal (as defined below) and Mr. Khattar indicated that Supernus’s board of directors was not supportive of a further increase to the Supernus June 6 Proposal, and as a result, Supernus would not be able to further improve its offer.

On June 6, 2025, Supernus submitted a revised proposal to acquire all of the outstanding Shares of Sage for an upfront payment of $8.50 per Share in cash and one contingent value right per Share representing the right to receive $1.00 in cash payable upon Supernus booking annual net sales of ZURZUVAE of $250 million by December 31, 2027, $1.00 in cash payable upon Supernus booking annual net sales of ZURZUVAE of $300 million by December 31, 2028, $1.00 in cash payable upon Supernus booking annual net sales of ZURZUVAE of $375 million by December 31, 2030 and $0.50 in cash upon the first commercial sale of zuranolone following regulatory approval in Japan for the treatment of MDD by June 30, 2026 (the “Supernus June 6 Proposal”). The Supernus June 6 Proposal indicated an assumed fully diluted share count of approximately 66.5 million Shares.

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That same afternoon, Moelis sent a revised draft of the merger agreement and contingent value rights agreement reflecting comments from Saul Ewing. The revised draft merger agreement contemplated that the termination fee that would be payable by Sage in specified circumstances would be equal to a certain percentage of the upfront equity value of the Supernus June 6 Proposal. The revised draft merger agreement also reflected that Supernus requested additional information on whether the treatment of equity awards set forth in Sage’s original draft merger agreement (i.e., that all equity awards would be fully accelerated and cashed out at closing, with all performance based restricted stock units deemed to vest at their maximum levels of achievement) was in fact required by Sage’s equity plans and award agreements.

Following submission of the Supernus June 6 Proposal, representatives of Goldman Sachs and Moelis spoke. During this conversation, Moelis provided context behind the Supernus June 6 Proposal. The representatives of Moelis also confirmed that Supernus could not justify, based on information then available, further increasing the valuation in the Supernus June 6 Proposal. Moelis also identified a number of priority diligence items Supernus had requested prior to signing.

On June 7, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Kirkland and Goldman Sachs. During the meeting, Goldman Sachs discussed with the Board the Supernus June 6 Proposal. It was noted that Supernus also sent Sage a markup of the merger agreement and form of contingent value rights agreement. Representatives of Goldman Sachs reviewed its preliminary financial analyses of the Supernus June 6 Proposal and discussed the context provided by Moelis, including noting that Moelis had indicated that Supernus was not in a position to further increase the valuation of the Supernus June 6 Proposal. Mr. Greene provided an update on his call with Mr. Khattar, characterizing his efforts to further negotiate the Supernus June 6 Proposal and Mr. Khattar’s indication that the Supernus board of directors would not support a further increase to the Supernus June 6 Proposal. Representatives from Goldman Sachs characterized the feedback received from Moelis and Supernus regarding ongoing due diligence, including the priority items Supernus had requested prior to signing. Mr. Greene then discussed with the Board Sage’s current forecast, whereby Sage would execute on its standalone plans focused on commercialization of ZURZUVAE and assumed a resource reallocation, a winddown of research and development activities, and a workforce reorganization, with the goal of extending Sage’s cash runway and achieving profitability from the ongoing commercialization of ZURZUVAE (the “June 2025 Projections”). The June 2025 Projections are discussed further in the section below captioned “ —Certain Financial Projections.” Mr. Greene also discussed with the Board the likelihood of meeting the contingent value rights milestones tied to achievement of net sales in the Supernus June 6 Proposal based on the June 2025 Projections. Mr. Greene and members of management discussed with the Board the risks and uncertainties inherent in the scenario reflected in the June 2025 Projections. As part of the Board’s discussion, the Board agreed that the strategic alternative of exercising Sage’s opt-out rights under the Biogen Collaboration Agreement would not be in the best interests of Sage and its stockholders given Biogen’s potential negative reaction to the exercise of the opt-out as well as other risks and uncertainties. The Board also had a discussion regarding whether and how to approach Party D in connection with Sage’s receipt of the Supernus June 6 Proposal, The Board discussed that Party D could always submit a superior offer to Sage in response to a public announcement of a transaction, subject to payment of a breakup fee which would be set forth in the merger agreement. Representatives of Kirkland discussed Supernus’s markups of the merger agreement and form of contingent value rights agreement, noting key open issues, priorities from a negotiation perspective and potential timing considerations. The representatives of Kirkland noted that Supernus had not yet provided a markup of the disclosure schedules to the merger agreement, and that Sage would work to provide Supernus with an updated draft by the following day. In addition, representatives from Kirkland discussed the mechanics should Party D submit a superior offer in response to an announcement of a signed deal with Supernus. It was noted that timing of signing would depend on Supernus’s remaining due diligence and willingness to finalize definitive agreements. Following further discussion, the Board confirmed alignment with the terms of the Supernus June 6 Proposal and authorized and directed management to pursue negotiation of the definitive agreements with Supernus consistent with the parameters discussed during the meeting, and subject to final approval by the Board. Representatives from Goldman Sachs then provided an update with respect to Party C, including recent discussions, due diligence requests, and potential timing. Party C had indicated to

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representatives of Goldman Sachs that it remained interested only in an asset acquisition of ZURZUVAE and that it planned to submit a revised proposal prior to Sage’s annual meeting of stockholders. Sage management then discussed with the Board the following compensation matters that Sage management recommended proposing to Supernus in connection with finalizing a transaction: (i) proposed changes to the existing severance and change in control agreements entered into with certain members of Sage’s management team, as previously discussed with the Board in early 2025 and with the Compensation Committee in December 2024 and on May 11, 2025 and June 3, 2025, (ii) the analysis of the impact of Internal Revenue Code Sections 280G and 4999 on certain payments expected to be made to Sage’s management team members in the event of a change in control, and the cost of a proposed gross-up arrangement for Mr. Greene, which would only be relevant if certain contingent value rights milestones in the Supernus June 6 Proposal were achieved; (iii) a proposed non-executive transaction bonus pool of $450,000 to incentivize a limited number of non-executive employees in the period between signing and closing to complete a transaction, and (iv) the treatment of Sage’s outstanding performance restricted stock units, taking into consideration Sage’s likelihood of achieving performance metrics in a future standalone scenario absent a transaction with Supernus. After members of Sage management, including Mr. Greene, left the meeting, the Board further discussed these matters in consultation with its advisors and authorized Sage’s management to seek the compensation matters described by Sage management in connection with finalizing a transaction with Supernus on the basis of the Supernus June 6 Proposal.

Following the Board meeting on June 7, 2025, representatives of Sage communicated to Supernus that it was prepared to proceed with finalizing a transaction on the basis of the Supernus June 6 Proposal.

On June 8, 2025 and June 9, 2025, representatives of Kirkland provided Saul Ewing with a revised draft of the merger agreement, form of contingent value rights agreement, and summarized the proposed compensation matters authorized by the Board at the June 7, 2025 meeting. The revised merger agreement draft contemplated that the termination fee that would be payable by Sage in specified circumstances would be equal to a certain percentage of the transaction’s value. Representatives of Kirkland also provided Saul Ewing with a revised draft of the disclosure schedules, which included exceptions to the interim operating covenants in the merger agreement that would allow Sage to establish a $450,000 non-executive transaction bonus pool, amend the existing severance and change in control agreements entered into with certain members of Sage’s management team, and enter into an agreement with Mr. Greene to provide for a 280G gross up in the event that any of the net sales milestones set forth in the form of contingent value rights agreement were achieved, in each case consistent with the authorizations granted by the Board on June 7th. Between June 8, 2025, and the execution of the Merger Agreement on June 13, 2025, representatives of Kirkland and Saul Ewing exchanged subsequent drafts and spoke further regarding the terms of the merger agreement, including the proposed termination fee, the proposed compensation matters, the provisions related to regulatory filings and the outside date, among other matters. During these conversations, representatives of Kirkland and Mr. Greene confirmed their expectation that the Board would not support a transaction with Supernus in the event that the termination fee was equal to a certain percentage or greater. Following further discussion and negotiation on this topic, the parties aligned on a termination fee equal to 3.99% of the upfront value of the Supernus June 6 Proposal. In addition, Sage agreed to remove the request to provide Mr. Greene with a 280G gross up payment.

On June 8, 2025, Mr. Greene had a conversation with Mr. Khattar, during which Mr. Greene indicated a desire to reach alignment on the terms of the definitive agreements prior to Sage’s annual stockholder meeting on June 11, 2025.

On June 9, 2025, representatives of Goldman Sachs and Moelis spoke regarding timing for finalizing the proposed transaction and outstanding due diligence requests.

Also on June 9, 2025, representatives of Goldman Sachs had a follow-up call with Party C during which Party C indicated it would not be able to share perspectives on value ahead of Sage’s annual stockholder meeting on June 11, 2025, and that Party C would require a few additional weeks to present a proposal. The representative of Party C also informed Goldman Sachs that Party C would need at least 4 weeks of continued diligence given other organizational priorities that were making it difficult to quickly evaluate a transaction at this time.

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On June 10, 2025, Goldman Sachs provided a relationships disclosure letter to Sage.

On June 11, 2025, Sage held its annual stockholder meeting.

On June 11, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Kirkland, WilmerHale, Goldman Sachs, and Joele Frank. During the meeting, Mr. Greene provided an update on the ongoing effort to finalize a transaction with Supernus, including that Sage was proposing to sign the merger agreement on Friday, June 13, 2025, and publicly announce the transaction before the opening of the markets on the following Monday. Goldman Sachs then led a discussion of the Supernus June 6 Proposal and reviewed its preliminary financial analysis of the Supernus June 6 Proposal based on the June 2025 Projections. Mr. Greene and other members of management provided updates on their interactions with Supernus, including with respect to ongoing due diligence. Representatives of Kirkland reviewed the material terms of the transaction documents and discussed the negotiation with Supernus concerning the termination fee.

Between June 11, 2025 and June 13, 2025, Sage, Supernus and their respective legal and financial advisors worked to finalize the merger agreement, disclosure schedules and form of contingent value rights agreement. During this time, representatives from Supernus continued to request additional due diligence materials, which Sage provided and representatives of Sage and Supernus continued to participate in due diligence meetings.

On June 12, 2025, Mr. Greene and Mr. Khattar spoke to discuss the planned execution and announcement of the transaction. They aligned that the parties expected to sign the merger agreement following the close of markets the following day and announce the transaction prior to the opening of the markets on Monday, June 16, 2025. That same day, representatives of Goldman Sachs, Moelis, Kirkland and Saul Ewing spoke to align on the same timing.

On the afternoon of June 13, 2025, Sage and Supernus finalized the terms of the merger agreement, the disclosure schedules and the form of contingent value rights agreement.

Following the close of markets on June 13, 2025, the Board held a meeting, which was also attended by Sage management and representatives of Kirkland and Goldman Sachs. During the meeting, representatives of Kirkland discussed with the Board key considerations in connection with its review of the proposed merger between Sage and Supernus based on the Supernus June 6 Proposal, noting that each member of the Board could make their decision based on all available information and considering all factors they deemed relevant to the decision, including financial and valuation analysis, as well as other factors such as certainty of closing and the individual director’s assessment of risks and uncertainties associated with other strategic alternatives of Sage. The Board discussed the June 2025 Projections and discussed and revisited questions raised by directors throughout the process of reviewing the June 2025 Projections and the information provided by Sage management in order to resolve these questions. The Board also discussed inherent risks associated with Sage’s ongoing litigation matters. Following this discussion, the Board reaffirmed that Goldman Sachs was authorized to use the June 2025 Projections for purposes of its financial analyses. Representatives of Goldman Sachs then reviewed with the Board its financial analysis of the Supernus June 6 Proposal and representatives of Kirkland summarized the changes to the merger agreement and related transaction documents that resulted from the final negotiations with Supernus and the proposed resolutions that had been provided to the Board in advance of the meeting. The Board then engaged in further discussion, including a discussion regarding the various factors described under the caption “ — Reasons for Recommendation,” following which each member of the Board confirmed that their questions had been addressed and affirmed their support for the proposed transaction with Supernus. Representatives from Kirkland then reviewed with the Board the relationships disclosure letter from Goldman Sachs that had been provided to the Board prior to the meeting. Goldman Sachs then rendered to the Board an oral opinion, which was subsequently confirmed by delivery of a written opinion dated June 13, 2025, that, as of such date and based on and subject to the various assumptions made, procedures followed, matters considered

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and limitations on the review undertaken in preparing such opinion as set forth therein, the Merger Consideration to be paid to the holders (other than Supernus and its affiliates) of Shares pursuant to the Merger Agreement was fair from a financial point of view to such holders. A detailed discussion of Goldman Sach’s opinion is included in the section below captioned “ —Opinion of Goldman Sachs & Co. LLC.” Following this, the Board (i) determined that the Merger Agreement and the Transactions, including the Offer and the Merger, were fair to, and in the best interest of, Sage and its stockholders, (ii) declared it advisable to enter into the Merger Agreement, (iii) approved the execution, delivery and performance by Sage of the Merger Agreement and the consummation of the Transactions, including the Offer and the Merger, (iv) resolved that the Merger shall be effected under Section 251(h) of the DGCL, and (v) resolved to recommend that the stockholders of Sage tender their Shares to Purchaser pursuant to the Offer, in each case, on the terms and subject to the conditions of the Merger Agreement.

From time to time throughout the Board’s strategic alternatives process, the Board discussed (among other things) Sage’s ongoing derivative litigation with its legal advisors. This discussion included the strengths and weaknesses of the claims, the likelihood of success of such claims, and potential damages recoveries. The allegations of derivative liability against the Board and certain officers were not a factor in the Board’s decision to enter into the strategic alternatives process that included a potential sale of Sage. Based upon its discussions with counsel, the Board ultimately concluded that given the costs to pursue the derivative litigation, the significant uncertainty regarding the case, the likelihood of success given the defenses available to the defendants at various stages in the litigation, the potential damages, the complexity and uncertainty around any calculation of damages, the distraction to Sage of the continued pendency of the case and the likely significant time frame to recovery, the opportunity to preserve the derivative claims was ultimately not material to the Board’s overall consideration of whether or not to enter into the Merger Agreement with Supernus.

Following the Board meeting on June 13, 2025, Sage and Supernus executed the Merger Agreement.

Before the opening of trading on June 16, 2025, Sage and Supernus issued a press release announcing the execution of the Merger Agreement, and Sage and Supernus each filed a Current Report on Form 8-K.

Reasons for Recommendation

At a meeting on June 13, 2025, the Board unanimously (i) determined that the Merger Agreement and the Transactions, including the Offer and the Merger, are fair to, and in the best interest of, Sage and its stockholders, (ii) declared it advisable to enter into the Merger Agreement, (iii) approved the execution, delivery and performance by Sage of the Merger Agreement and the consummation of the Transactions, including the Offer and the Merger, (iv) resolved that the Merger will be effected under Section 251(h) of the DGCL, and (v) resolved to recommend that the stockholders of Sage tender their Shares to Purchaser pursuant to the Offer, in each case on the terms and subject to the conditions of the Merger Agreement. The Board consulted with members of Sage’s management and representatives from Goldman Sachs, Kirkland and Skadden at various times, and considered a number of reasons, including the following non-exhaustive list of material reasons (not in any relative order of importance) that the Board believes support its unanimous decision and recommendation.

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The Board also considered a variety of potentially negative factors in its deliberations concerning the Merger Agreement, the Offer and the Merger, including the following non-exhaustive list of material reasons (not in any relative order of importance):

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The foregoing discussion of the information and reasons considered by the Board is not intended to be exhaustive but includes the material reasons considered by the Board. In view of the variety of reasons considered in connection with its evaluation of the Merger, the Board did not find it practicable to, and did not, quantify or otherwise assign relative weights to the specific reasons considered in reaching its determination and recommendation. The Board did not undertake to make any specific determination as to whether any reason, or any particular aspect of any reason, supported or did not support its ultimate determination. Rather, the directors made their determinations and recommendations based on the totality of the information presented to them, and the judgments of individual members of the Board may have been influenced to a greater or lesser degree by different factors. The Board concluded that the risks, uncertainties, restrictions and potentially negative factors associated with the Offer and Merger were substantially outweighed by the potential benefits of the Offer and Merger.

Certain Financial Projections

Although Sage historically has provided guidance as to its projected financial and operational results for its then-current fiscal year, Sage does not otherwise, as a matter of course, make long-term projections as to future

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performance available to the public, given, among other things, the inherent difficulty of predicting financial performance for future periods and the likelihood that the underlying assumptions and estimates may not be realized.

June 2025 Projections

As part of the Board’s review and evaluation of the Supernus June 6 Proposal, Sage’s management presented an updated version of the May 2025 Budget Projections (as defined below) that assumed U.S. peak sales of ZURZUVAE of $0.9 billion whereby Sage would execute on its standalone plans focused on commercialization of ZURZUVAE and assumed a resource reallocation, a winddown of research and development activities, and a workforce reorganization, with the goal of extending Sage’s cash runway and achieving profitability from the ongoing commercialization of ZURZUVAE (the “June 2025 Projections”). The June 2025 Projections assumed a reduction in headcount and corporate spending, a reduction in research and development spending to approximately $5 million per year and the elimination of the future financing rounds.

The June 2025 Projections were presented to the Board in connection with its consideration of the Transactions, and, at the instruction of the Board, were relied upon by Goldman Sachs in connection with the rendering of its opinion to the Board and in performing its financial analysis as described in the section below captioned “—Opinion of Goldman Sachs & Co. LLC” and were the only financial projections with respect to Sage used by Goldman Sachs in performing its financial analysis in connection with the rendering of its opinion.

The June 2025 Projections assume estimated cash of $424 million as of March 31, 2025, $2 billion in federal net operating loss carryforwards as of December 31, 2024, $131 million in federal tax credits as of December 31, 2024, and taxes based on a 21% tax rate. For purposes of enabling Goldman Sachs to calculate the discounted cash flow described further in the section below captioned “—Opinion of Goldman Sachs & Co. LLC,” Sage’s management calculated the estimated benefit of taxes saved from tax attributes generated as a result of current and future estimated losses based on a 21% tax rate, which, for the avoidance of doubt, is not reflected in the values in the table below. The June 2025 Projections assume that Milestone 1 under the CVR Agreement would be satisfied in the fourth quarter of 2025 and that Milestone 2, Milestone 3 and Milestone 4 under the CVR Agreement would not be satisfied by their respective deadline dates. The following table summarizes the June 2025 Projections:

June 2025 Projections

(Amounts in Millions)

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Additional Projected Financial Information

As part of the Board’s regular process for evaluating Sage’s business, strategic and financial position, including with respect to investments in ZURZUVAE under the Biogen Collaboration Agreement, Sage’s management regularly prepared and presented to the Board customary non-public, unaudited financial projections of Sage.

In September 2024, as part of Sage’s evaluation of potential options to optimize Sage’s business strategies in the event SAGE-718 would be discontinued, Sage’s management presented to the Board an internal forecast assuming that Sage discontinued its pipeline and focused on the commercialization of ZURZUVAE. This forecast is referred to as the “September 2024 ZURZUVAE Only Projections.” The September 2024 ZURZUVAE Only Projections are summarized below:

September 2024 ZURZUVAE Only Projections

(Amounts in Millions)

Also in September 2024, as part of Sage’s regular evaluation of ZURZUVAE’s ongoing performance, Sage’s management presented to the Board an internal forecast and assessment of the market potential of ZURZUVAE in PPD based on an assumed hypothetical higher level of investment in ZURZUVAE by both Sage and Biogen. This forecast is referred to as the “September 2024 Elevate Projections.” The September 2024 Elevate Projections are summarized below:

September 2024 Elevate Projections

(Amounts in Millions)

In January 2025, following receipt of the Biogen January 10 Proposal and in connection with the Board’s evaluation of the Biogen January 10 Proposal, Sage’s management revised its internal ZURZUVAE forecasts to model three different cases assuming U.S. peak sales of ZURZUVAE of $0.9 billion (the “January 2025 Budget Projections”), $1.1 billion (the “January 2025 Management Projections”) and $1.2 billion (the “January 2025 Upside Projections”) respectively (collectively, the “January 2025 Projections”). The January 2025 Projections each assumed risk adjusted peak product sales of SAGE-324 of $0.2 billion, risk adjusted peak product sales of SAGE-319 of $0.3 billion, and risk adjusted peak product sales of Sage’s platform candidates of $0.1 billion per asset. The January 2025 Budget Projections assumed illustrative follow-on financing rounds of $150 million in

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2026, $200 million in 2027, $200 million in 2028, $250 million in 2029 and $250 million in 2030. The January 2025 Management Projections and January 2025 Upside Projections each assumed illustrative follow-on financing rounds of $150 million in 2026, $200 million in 2027 and $200 million in 2028. The Board was provided with a portion of the January 2025 Projections. The following tables summarize the January 2025 Projections presented to the Board:

January 2025 Budget Projections (Risk Adjusted)

(Amounts in Millions)

January 2025 Management Projections (Risk Adjusted)

(Amounts in Millions)

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January 2025 Upside Projections (Risk Adjusted)

(Amounts in Millions)

In February 2025, as part of the Board’s ongoing consideration of various strategic alternatives, including the possibility of repurchasing ZURZUVAE from Biogen, Sage’s management presented a revised version of the September 2024 Elevate Projections (the “February 2025 Elevate Projections”), which assumed that Sage could successfully reacquire its rights to ZURZUVAE from Biogen and subsequently increase Sage’s level of investment in ZURZUVAE. The February 2025 Elevate Projections are summarized below:

February 2025 Elevate Projections

(Amounts in Millions)

Also in February 2025, the Board was presented with projected revenue, operating expenses and operating income derived from the February 2025 Elevate Projections in scenarios where Sage successfully reacquired its rights to ZURZUVAE from Biogen and entered into a collaboration agreement with Biogen or another third party for zuranolone sales in the EU, in each case with royalty terms consistent with the Biogen Collaboration Agreement:

February 2025 Elevate Projections

(Amounts in Millions)

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On or around April 17, 2025, as described above in the section captioned “—Background of the Offer and the Merger,” Sage provided Supernus and Party E with certain financial information, including information consistent with the January 2025 Management Projections summarized below:

Information Provided to Supernus and Party E

(Amounts in Millions)

In May 2025, as part of the Board’s ongoing consideration of various strategic alternatives, Sage’s management presented revised versions of the January 2025 Projections, which continued to assume U.S. peak sales of ZURZUVAE of $0.9 billion (the “May 2025 Budget Projections”), $1.1 billion (the “May 2025 Management Projections”) and $1.2 billion (the “May 2025 Upside Projections”) respectively (collectively, the “May 2025 Projections”). The May 2025 Projections each also continued to assume risk adjusted peak product sales of SAGE-324 of $0.2 billion, risk adjusted peak product sales of SAGE-319 of $0.3 billion, and risk adjusted peak product sales of Sage’s platform candidates of $0.1 billion per asset. The May 2025 Budget Projections continued to assume illustrative follow-on financing rounds of $150 million in 2026, $200 million in 2027, $200 million in 2028, $250 million in 2029 and $250 million in 2030. The May 2025 Management Projections and May 2025 Upside Projections each continued to assume illustrative follow-on financing rounds of $150 million in 2026, $200 million in 2027 and $200 million in 2028. The following tables summarize the May 2025 Projections presented to the Board:

May 2025 Budget Projections (Risk Adjusted)

(Amounts in Millions)

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May 2025 Management Projections (Risk Adjusted)

(Amounts in Millions)