SEC Form 424B5 filed by Milestone Pharmaceuticals Inc.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this prospectus supplement or the accompanying prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common shares, Pre-Funded Warrants and accompanying Common Warrants. For a more complete understanding of our Company and this offering, we encourage you to read and consider carefully the more detailed information in this prospectus supplement and the accompanying prospectus, including the information incorporated by reference in this prospectus supplement or the accompanying prospectus, and the information included in any free writing prospectus that we have authorized for use in connection with this offering, including the information under the heading “Risk Factors” beginning on page S-9 of this prospectus supplement and in the section entitled “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2024, our quarterly report on Form 10-Q for the three months ended March 31, 2025 and in any subsequent reports we file with the SEC after the date of this prospectus supplement, which are incorporated by reference into this prospectus supplement and the accompanying prospectus along with our consolidated financial statements and notes to those consolidated financial statements, before making an investment decision.

Company Overview

We are a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines. Our objective is to commercialize and develop CARDAMYST (also known as etripamil) in the United States as a fast-acting, portable nasal spray treatment for use by patients anywhere, anytime an attack of supraventricular tachycardia, or “SVT” occurs. We are also developing etripamil for the indication of atrial fibrillation with rapid ventricular rate, or “AFib-RVR.”

CARDAMYST (etripamil) nasal spray

We are currently focused on obtaining marketing approval of CARDAMYST for the treatment of paroxysmal supraventricular tachycardia, or “PSVT” from the U.S. Food and Drug Administration, or “FDA.” In March 2025, we announced that we received a Complete Response Letter, or “CRL,” regarding our New Drug Application, or “NDA,” for CARDAMYST (etripamil) nasal spray for the treatment of PSVT. See “New Drug Application Status” below for a recent update on the NDA.

We are also developing etripamil nasal spray for a subsequent indication to treat patients with AFib-RVR. Similar to our approach for PSVT, we believe that etripamil has the potential to help the person experiencing a symptomatic episode of AFib-RVR to self-treat themselves and to conveniently, reliably, and quickly, reduce their elevated heart rate, with the goal of reducing the need for emergency department utilization. We completed a successful Phase 2 study in patients presenting urgently with AFib-RVR, i.e., to an emergency department. We publicly presented these positive Phase 2 data in November 2023, which demonstrated that patients receiving etripamil nasal spray experienced rapid and statistically superior ventricular rate reduction and improved symptom-relief compared to placebo, with safety and tolerability findings generally consistent with those observed in our PSVT program. This data supports the development of etripamil—self-administered in the medically unmonitored setting—​for the treatment of AFib-RVR and, following dialogue with FDA, have finalized a Phase 3, potentially registrational study.

PSVT Market Overview

PSVT is a condition that causes a patient’s heart to suddenly start beating faster than normal. It can be life-altering as PSVT is highly symptomatic, characterized by unpredictable attacks of a racing heart, often exceeding 150 beats per minute. Symptoms of PSVT arise suddenly and may include palpitations, sweating, chest pressure or pain, shortness of breath, sudden onset of fatigue, lightheadedness or dizziness, fainting, and anxiety, causing many patients to interrupt their daily activities at the time of symptom-onset. The impact and morbidity from an episode of PSVT can be especially detrimental in patients with underlying cardiovascular or medical conditions, such as heart failure, obstructive coronary disease, or dehydration. The uncertainty of when such an attack of PSVT

 

will strike or how long it will persist is often anxiety-provoking, reducing patients’ quality of life and preventing participation in many desired activities. Drugs approved for the treatment of attacks of PSVT include adenosine, verapamil, and diltiazem, with all being administered intravenously under medical supervision, usually in the emergency department. Other oral drugs are sometimes used to treat attacks in a concept called “pill in the pocket.” However, those drugs have never been proven effective or safe and are not approved for this use. Doctors are often frustrated by the lack of effective treatment options besides a prolonged, unpleasant, and costly trip to the emergency department or, for some patients, an invasive ablation procedure. PSVT can be traumatic for patients, frustrating for healthcare providers, and costly for payors. With no pharmaceutical innovation in the treatment of PSVT for more than 30 years and a movement in the healthcare system to enable patient-centered care, we believe there is an opportunity to help patients living with PSVT to take greater control over their PSVT.

We believe that PSVT is a large and under-recognized market which we estimate affects more than two million Americans. From this diagnosed population, we define the immediate target addressable market for CARDAMYST as approximately 60% of patients who are actively managed by clinical cardiologists, interventional cardiologists and electrophysiologists. The remaining patients with PSVT can become addressable over time, as they are inconsistently managed (cycling in and out of the healthcare system) and/or being managed less frequently by primary care healthcare providers. Furthermore, PSVT is expected to increase in prevalence in coming years as wearable electrocardiogram, or “ECG,” technology (e.g., smartphone, watches) becomes both more adept at diagnosing PSVT and more widely used by patients and clinical practitioners, in turn shortening the current two to three year average time to diagnosis.

Following the release of data from the RAPID clinical study in market research, cardiologists reported a willingness to prescribe CARDAMYST to approximately 50% of the patients with PSVT in their care, which suggests approximately 500,000 to 800,000 patients can potentially be treated with CARDAMYST in peak years. Additionally, we believe that this cardiology-identified group of patients may use CARDAMYST to treat a median of three to five episodes per year, based on the projected number of self-reported longer and more intense episodes experienced by patients, as well as the patient utilization experience in our Phase 3 clinical trials. This implies a peak demand potential in the United States for CARDAMYST of 2.5 million to 4 million episodes treated per year.

Current treatment for PSVT also consumes significant healthcare resources. Research published in the American Journal of Cardiology in 2020 shows that total healthcare expenditures in the year following a diagnosis of PSVT ranged from $20,000 to $30,000 per patient which were significantly higher than the expenditures observed for patients without PSVT. These significant increases included increased emergency department visits and hospitalization costs. Of note, catheter ablations following diagnosis represented only 23% of this increased spend, meaning most costs were unrelated to ablations. Recent data from the Healthcare Cost and Utilization Project (HCUP) database indicate that in 2019 there were approximately 140,000 emergency department, or “ED,” visits for PSVT when coded in the primary diagnostic position, and a total of approximately 525,000 ED visits when PSVT was coded in any diagnostic position. Of these, approximately 25% of ED admissions for PSVT resulted in a hospital admission. HCUP estimates a total of approximately 40,000 to approximately 120,000 inpatient admissions for PSVT in 2019 (based again if PSVT were found in the primary v. any diagnostic position). Despite the effectiveness of catheter ablation, claims data suggests that only approximately 15% of patients with PSVT are ablated over a three-year period, leading to a total of approximately 100,000 catheter ablations annually. In total, at least $5 billion is spent annually in the United States on the management of PSVT.

AFib-RVR Market Overview

Atrial Fibrillation, or “AFib,” is a common cardiac arrhythmia with an irregular and often rapid heart rate that is often markedly symptomatic and, without proper treatment, can increase the risk of stroke, heart failure, and other cardiovascular complications. A common complication of AFib is a rapid heart rate, also referred to as AFib-RVR, which is frequently defined as a heart rate ≥ 110 beats per minute. The occurrence of a rapid ventricular rate, or “RVR,” in patients with atrial fibrillation increases the likelihood of marked symptoms including heart palpitations, shortness of breath and weakness. There are two commonly used pharmacological approaches to chronically manage AFib, rhythm control

 

and rate control. Regardless of the chronic approach, break-through episodes of rapid heart rate occur frequently; and when faced with a sudden episode of AFib-RVR, acute rate control is needed, with most treatments being AV-nodal targeted drugs such as a beta blocker or calcium channel blocker. These treatments can be given intravenously, however this requires a burdensome trip to an emergency department which may lead to a hospital admission. Acute treatment can be attempted by administration of an oral rate control drug; however, such drugs do not adequately provide immediate or adequate ventricular rate control due to a 30- to 90-minute delayed onset of action, and, as a result, many patients need faster and more certain rate-reduction and symptom-resolution and so seek acute-medical care by going to the emergency department for treatment utilizing intravenous rate control and/or electrical cardioversion of their atrial fibrillation. Furthermore, the chronic administration of oral rate-control drugs does not broadly prevent episodes of AFib-RVR. Similar to PSVT, patients may feel a loss of control by needing to visit the emergency department for overcoming their AFib-RVR episode and the unpredictable nature of these episodes, which can occur anytime and anywhere. Doctors have expressed frustration at the lack of options for patients to self-manage these acute rate attacks; and payor organizations would prefer to treat the AFib-RVR attacks in a more cost effective and time-efficient manner.

An estimated 10 million Americans suffer from AFib. The prevalence of AFib is expected to grow to greater than 12 million by 2030. A subset of patients with AFib experiences episodes of abnormally high heart rate most often accompanied by palpitations, shortness of breath, dizziness, and weakness. While these episodes, known as AFib-RVR, may be treated by oral calcium channel blockers and/or beta blockers, patients frequently seek acute care in the ED to address symptoms. In 2019, nearly 1.1 million patients were admitted to the ED due to AFib symptoms. Initial data suggests that approximately 60% of all AFib ED visits were attributable to AFib-RVR, as symptoms driving patients to seek care generally become more pronounced at higher heart rates. Treatment for such symptoms typically includes medically supervised intravenous administration of calcium channel blockers or beta blockers, or electrical cardioversion. With little available data for AFib-RVR, we believe, based on our initial market research, that 30% to 40% of patients with AFib experience one or more symptomatic episodes of RVR per year that require treatment, suggesting a target addressable market of up to approximately four to five million patients by 2030 for etripamil in patients with AFib-RVR.

We believe that etripamil has the potential to be developed such that it can be used by patients to rapidly reduce their heart rate at home, self-administered, to provide a supplemental option to either the acute oral rate or rhythm control strategy their physician would use. When presented with a target product profile reflecting this potential use case, cardiologists and electrophysiologists in a 2021 market research study perceived utility in the product profile and indicated that they would prescribe to approximately 67% of their patients that experience episodes of AFib-RVR. They further indicated that a rapidly-acting intranasal calcium channel blocker could serve as a “bridge” to the longer onset times of acute oral agents. According to physicians, it can take hours for patients to feel an alleviation of symptoms using acute oral rate or rhythm control. During this time, patients may experience concerning symptoms that often prompt them to seek emergency care. We believe that the combination of convenient delivery, potency, rapid onset and short duration of action of etripamil has the potential to move the current treatment setting for some acute episodes of AFib out of the burdensome and costly emergency department.

Current AFib management consumes significant healthcare resources in the United States. The American Heart Association published a report in 2016 summarizing the current and projected cost burden of cardiovascular diseases in the United States. This report suggests atrial fibrillation resulted in $25 billion in direct medical costs in 2016 (approximately 7% of all cardiovascular diseases) and another $7 billion in indirect costs (i.e., up to $32 billion in total costs). Additionally, the forecasted growth in atrial fibrillation prevalence is anticipated to result in healthcare expenditures of $46 billion in direct costs and $10 billion in indirect costs in the United States by 2030.

Recent Developments

Preliminary Balance of Cash and Cash Equivalents and Short-Term Investments

As of June 30, 2025, we estimate that we had approximately $43.4 million in cash and cash equivalents and short-term investments.

 

This preliminary estimate of cash and cash equivalents and short-term investments was prepared based on information available as of the date of this prospectus and may vary from our actual cash and cash equivalents and short-term investments balance as of June 30, 2025. Our financial closing procedures as of and for the six months ended June 30, 2025 are not yet complete and, as a result, our preliminary balance of cash and cash equivalents and short-term investments upon completion of those procedures may differ materially from our preliminary estimate. This preliminary estimate is subject to change, and any changes may be material. Further, this preliminary estimate does not present all information necessary for an understanding of our financial condition and liquidity as of and for the six months ended June 30, 2025. This preliminary estimate of cash and cash equivalents and short-term investments should not be viewed as a substitute for such balances derived from financial statements prepared in accordance with accounting principles generally accepted in the United States. Accordingly, you should not draw any conclusions based on the foregoing estimate of cash and cash equivalents and short-term investments, and should not place undue reliance on this preliminary estimate. We assume no duty to update this preliminary estimate except as required by law.

The preliminary balance of cash and cash equivalents and short-term investments at June 30, 2025 included in the registration statement of which this prospectus forms a part has been prepared by, and is the responsibility of, our management. PricewaterhouseCoopers LLP has not audited, reviewed, examined, compiled, nor applied agreed-upon procedures with respect to this preliminary financial data. Accordingly, PricewaterhouseCoopers LLP does not express an opinion or any other form of assurance with respect thereto.

New Drug Application Status

On July 11, 2025, we announced that the FDA had accepted our response to the Complete Response Letter regarding our NDA for CARDAMYST (etripamil) nasal spray for the treatment of PSVT. In the CRL, the FDA identified two key Chemistry, Manufacturing and Controls, or CMC, issues that needed to be addressed. The FDA requested that we submit additional information on nitrosamine impurities based on new draft guidance issued after the NDA submission. The FDA also stated in the CRL that, before approval could be granted, it would need to conduct an inspection of a facility listed in the NDA, to ensure it is in compliance with current Good Manufacturing Practices. The facility mentioned in the NDA previously performed a portion of the testing required to release etripamil final product but subsequently changed ownership during the FDA’s review of the NDA. The FDA has assigned a Prescription Drug User Fee Act target action date of December 13, 2025, to act on our response to the CRL. If our response to the CRL satisfies the FDA’s concerns and the NDA is approved, we believe that CARDAMYST will be the first and only self-administered therapy for the rapid termination of episodes of PSVT wherever and whenever they occur.

Amendment of Royalty Purchase Agreement with RTW

In 2023, we entered into a purchase and sale agreement, or the Royalty Purchase Agreement, with an affiliate of RTW Investments, LP, or RTW, pursuant to which RTW agreed to purchase, following the FDA approval (subject to certain conditions) of etripamil on or prior to September 30, 2025, or the Approval Date, the right to receive royalty payments on the annual net product sales of etripamil in the United States, in exchange for a purchase price of $75.0 million. We and RTW entered into an amendment to the Royalty Purchase Agreement, dated as of July 10, 2025, or the Amendment, to provide for a three-month extension of the Approval Date. Pursuant to the Amendment, in order to receive the $75.0 million royalty payment, we must receive marketing approval from the FDA on or prior to December 31, 2025, and the closing conditions specified in the Royalty Purchase Agreement must be met. This represents a contingent future source of funding for Milestone.

Corporate Information

We were incorporated under the Canada Business Corporations Act in 2003 and continued under the Business Corporations Act (Québec) in 2017. Our principal executive offices are located at 1111 Dr. Frederik-Philips Blvd., Suite 420, Montréal, Québec, Canada H4M 2X6, and our telephone number is (514) 336-0444. In January 2017, we incorporated our wholly owned subsidiary, Milestone Pharmaceuticals USA, Inc., a Delaware corporation. Our U.S. offices are located at 6210 Ardrey Kell Rd, Suite 650, Charlotte, NC 28277 and our telephone number is (704) 848-5316. Our corporate website address is www.milestonepharma.com. Information contained on, or accessible through, our website is

 

not a part of this prospectus supplement. We have included our website in this prospectus supplement solely as an inactive textual reference.

Implications of Being a Smaller Reporting Company and a Non-Accelerated Filer

We are a “smaller reporting company,” as defined in Rule 12b-2 of the Securities Exchange Act of 1934, or the Exchange Act. We may continue to be a smaller reporting company if either (i) the market value of our shares held by non-affiliates is less than $250 million or (ii) our annual revenue was less than $100 million during the most recently completed fiscal year for which audited financial statements are available as of the determination date and the market value of our shares held by non-affiliates is less than $700 million. As a smaller reporting company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, we may present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation. If investors consider our common shares less attractive as a result of our election to use the scaled-back disclosure permitted for smaller reporting companies, there may be a less active trading market for our common shares and our share price may be more volatile.

Additionally, as a non-accelerated filer, we may continue to rely on the exception from compliance with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended.

 

THE OFFERING

       common shares.

Each common share is being offered and sold together with (i) an accompanying Series A Common Warrant and (ii) an accompanying Series B Common Warrant at a combined offering price of $      .

We are also offering, in lieu of our common shares to certain investors that so choose, Pre-Funded Warrants to purchase        common shares. Each Pre-Funded Warrant is being offered and sold together with (i) an accompanying Series A Common Warrant and (ii) an accompanying Series B Common Warrant at a combined offering price of $      . The purchase price of each Pre-Funded Warrant with accompanying Common Warrants will equal the price per share at which our common shares with accompanying Common Warrants are being sold to the public in this offering, minus $0.001, and the exercise price of each Pre-Funded Warrant will equal $0.001 per common share. Each Pre-Funded Warrant will be exercisable immediately and will not expire until exercised in full, subject to an ownership limitation. See “Description of Warrants—Description of Pre-Funded Warrants.” This prospectus supplement also relates to the offering of our common shares issuable upon the exercise of such Pre-Funded Warrants.

We are also offering (i) Series A Common Warrants to purchase up to        common shares and (ii) Series B Common Warrants to purchase up to        common shares. Each common share or Pre-Funded Warrant is being offered and sold together with (i) an accompanying Series A Common Warrant and (ii) an accompanying Series B Common Warrant. Each Series A Common Warrant will have an exercise price of $      per common share, subject to certain adjustments, will become exercisable immediately, and will expire one year from the date of issuance. The Series B Common Warrants allow us to force the exercise of such Series B Common Warrants upon certain stock price requirements. “Description of Warrants—​Description of Common Warrants.” This prospectus supplement also relates to the offering of the common shares issuable upon exercise of the Common Warrants.

       common shares, excluding any common shares issuable upon the exercise of the Warrants.

We estimate that our net proceeds from this offering will be approximately $      million, after deducting underwriting discounts and commissions and estimated offering expenses payable by us, excluding any proceeds received upon the exercise of the Common Warrants. We intend to use the net proceeds we receive from this offering, together with our existing cash and cash equivalents and short-term investments, to fund the commercialization and clinical development of etripamil, as well as for working capital and other

 

general corporate purposes. See “Use of Proceeds” for additional information. The Pre-Funded Warrants are exercisable by means of payment of the nominal cash purchase price upon exercise or through “cashless exercise”. Accordingly, we will not receive any meaningful additional funds upon the exercise of the Pre-Funded Warrants.

Investing in our common shares, Pre-Funded Warrants and accompanying Common Warrants involves significant risks. Please read the information contained in and incorporated by reference under the heading “Risk Factors” in this prospectus supplement beginning on page S-9 and under similar headings in the accompanying prospectus and any related free writing prospectus we have authorized for use in connection with this offering and the other documents that are incorporated by reference into this prospectus supplement, together with the other information included in or incorporated by reference into this prospectus supplement, before deciding whether to invest in our common shares, Pre-Funded Warrants and accompanying Common Warrants.

Our common shares trade on the Nasdaq Global Select Market under the symbol “MIST.” We do not intend to list the Warrants on the Nasdaq Global Market or any other national securities exchange or nationally recognized trading system. Without an active market, the liquidity of the Warrants will be limited.

The above discussion and table are based on 53,464,273 common shares outstanding as of March 31, 2025, and exclude:

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7,777,923 common shares issuable upon the exercise of outstanding options, at a weighted-average exercise price of $4.85 per share;

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916,484 common shares reserved for future issuance under our 2019 Equity Incentive Plan, or the 2019 Plan, as well as any future increases in the number of common shares reserved for issuance under the 2019 Plan;

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260,000 common shares reserved for future issuance under our 2021 Inducement Plan, or the 2021 Plan, as well as any future increases in the number of common shares reserved for issuance under the 2021 Plan;

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1,926,280 common shares reserved for future issuance under our 2019 Employee Share Purchase Plan, or the ESPP, as well as any future increases in the number of common shares reserved for issuance under the ESPP;

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12,910,590 common shares issuable upon the exercise of outstanding pre-funded warrants, at an exercise price of $0.001 per share;

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$75.0 million of our common shares remaining available for sale by us as of the date of this prospectus supplement pursuant to our Open Market Sale AgreementSM with Jefferies LLC, or Jefferies; and

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up to 15,653,393 common shares, of which (a) 10,766,391 common shares are issuable upon the conversion of Milestone’s senior secured convertible promissory notes, or the Notes, and (b) 4,887,001 additional common shares, which represents the maximum number of additional common shares issuable in connection with an adjustment to the conversion rate of the Notes if a holder of Notes exercises its conversion right upon the occurrence of certain transactions.

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Except as otherwise indicated, all information in this prospectus assumes no exercise of outstanding options, pre-funded warrants or Notes after March 31, 2025.

 

SUMMARY

This summary highlights selected information from this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our financial statements and related notes, and the exhibits to the registration statement of which this prospectus is a part, before making an investment decision.

Unless the context indicates otherwise, references in this prospectus to “Milestone,” “company,” “we,” “us” and “our” refer to Milestone Pharmaceuticals Inc.

Company Overview

We are a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines. Our lead product candidate, etripamil, is a novel and potent calcium channel blocker that we designed as a rapid-onset nasal spray to be self-administered by patients. We are developing etripamil for the treatment of specific arrhythmias with a lead indication to treat paroxysmal supraventricular tachycardia, or “PSVT”, and an indication to treat atrial fibrillation with rapid ventricular rate, or “AFib-RVR”.

PSVT, also referred to as supraventricular tachycardia, or “SVT”, is a condition characterized by an abnormality in the electrical system of the heart causing patients to have unexpected, often severely symptomatic episodes of rapid heart rate. Patients experiencing episodes of SVT often experience symptoms including palpitations, sweating, chest pressure or pain, shortness of breath, sudden onset of fatigue, lightheadedness or dizziness, fainting and anxiety. Calcium channel blockers have long been approved for the treatment of SVT as well as other cardiac conditions. Calcium channel blockers available in oral form are sometimes used prophylactically to attempt to control the frequency and duration of future episodes of SVT. For treatment of episodes of SVT, approved calcium channel blockers are administered intravenously under medical supervision, usually in the emergency department. We believe the combination of convenient nasal-spray delivery and rapid-onset of etripamil has the potential to shift the current treatment paradigm for episodes of SVT away from the burdensome and costly emergency department setting.

Atrial fibrillation, or “AFib”, is a common form of arrhythmia with an irregular and often rapid heart rate that is often markedly symptomatic and, without proper treatment, can increase the risk of stroke, heart failure, and other cardiovascular complications. A common complication of AFib is a rapid ventricular rate, or “AFib-RVR”, which is frequently defined as a heart rate ≥ 110 beats per minute. The occurrence of a RVR in patients with AFib increases the likelihood of marked symptoms including heart palpitations, shortness of breath and weakness. There are two commonly used pharmacological approaches to chronically manage AFib, rhythm control and rate control. Regardless of the chronic approach, when faced with a sudden episode of AFib-RVR, acute rate control is needed, and most treatments are oral AV-nodal targeted drugs such as a beta blocker or calcium channel blockers. However, these oral rate control drugs, when used acutely, do not adequately provide immediate or adequate ventricular rate control due to a 30- to 90-minute delayed onset of action, and, as a result, many patients need faster and more certain rate-reduction and symptom-resolution and so seek acute-medical care by going to the emergency department for treatment utilizing intravenous rate control and/or electrical cardioversion of their AFib. Similar to SVT, patients feel a loss of control by needing to visit the emergency department for overcoming their atrial fibrillation attack and the unpredictable nature of RVR episodes; doctors are frustrated by the lack of options for patients to self-manage these acute rate attacks; and payor organizations would prefer to treat the AFib-RVR attacks in a more cost effective and time-efficient manner.

Corporate Information

We were incorporated under the Canada Business Corporations Act in 2003 and continued under the Business Corporations Act (Québec) in 2017. Our principal executive offices are located at 1111 Dr. Frederik-Philips Blvd., Suite 420, Montréal, Québec, Canada H4M 2X6, and our telephone

 

number is (514) 336-0444. In January 2017, we incorporated our wholly owned subsidiary, Milestone Pharmaceuticals USA, Inc., a Delaware corporation. Our U.S. offices are located at 6210 Ardrey Kell Rd, Suite 650, Charlotte, NC 28277 and our telephone number is (704) 848-5316. Our corporate website address is www.milestonepharma.com. Information contained on, or accessible through, our website is not a part of this prospectus. We have included our website in this prospectus solely as an inactive textual reference.

Implications of Being an Emerging Growth Company and a Smaller Reporting Company

We qualify as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. An emerging growth company may take advantage of relief from some of the reporting requirements and other burdens that are otherwise applicable generally to public companies. These provisions include:

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being permitted to provide only two years of audited financial statements, in addition to any required unaudited interim financial statements, with correspondingly reduced “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure;

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not being required to comply with the auditor attestation requirements in the assessment of our internal control over financial reporting;

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not being required to comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financial statements;

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reduced disclosure obligations regarding executive compensation in our periodic reports, proxy statements and registration statements; and

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not being required to hold a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute payments not previously approved.

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We may take advantage of some or all of these reporting exemptions until we are no longer an emerging growth company. We will remain an emerging growth company until December 31, 2024. We may choose to take advantage of some but not all of these reduced burdens. For example, we have taken advantage of the reduced reporting requirements with respect to disclosure regarding our executive compensation arrangements, have presented only two years of audited financial statements and only two years of related “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure in our public filings, and have taken advantage of the exemption from auditor attestation on the effectiveness of our internal control over financial reporting. To the extent that we take advantage of these reduced burdens, the information that we provide shareholders may be different than you might obtain from other public companies in which you hold equity interests.

In addition, under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have irrevocably elected not to avail ourselves of this exemption from new or revised accounting standards and, therefore, we will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

We are also a “smaller reporting company” as defined in Rule 12b-2 promulgated under the Securities Exchange Act of 1934, as amended, or the Exchange Act. We may remain a smaller reporting company until we have a non-affiliate public float in excess of $250 million and annual revenues in excess of $100 million, or a non-affiliate public float in excess of $700 million, each as determined on an annual basis. Even after we no longer qualify as an emerging growth company, we may still qualify as a smaller reporting company, which would allow us to take advantage of many of the same exemptions from disclosure requirements.

The Securities We May Offer

We may offer common shares, preferred shares, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination, up to a total aggregate offering price of $250,000,000 from time to time in one or more offerings under this prospectus, together with any applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by

 

market conditions at the time of the relevant offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

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designation or classification;

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aggregate principal amount or aggregate offering price;

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maturity;

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original issue discount, if any;

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rates and times of payment of interest or dividends, if any;

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redemption, conversion, exchange or sinking fund terms, if any;

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conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange;

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ranking;

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restrictive covenants, if any;

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voting or other rights, if any; and

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important U.S. federal income tax and Canadian federal income tax considerations.

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The applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

We may sell the securities directly to investors or indirectly through underwriters, dealers or agents. We, and our underwriters, dealers or agents reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters, dealers or agents, we will include in the applicable prospectus supplement:

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the names of those underwriters, dealers or agents;

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applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment options, if any; and

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the estimated net proceeds to us.

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This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

Common Shares.   We may issue common shares from time to time. Under our articles, each holder of common shares is entitled to receive notice of, to attend and to vote at, all annual and special meetings of our shareholders. Each common share entitles the holder thereof to one vote at all meetings, other than meetings at which only holders of another particular class or series have the right to vote. Subject and subordinate to the prior rights and privileges of the holders of our preferred shares ranking before common shares, the holders of common shares are entitled to receive dividends as and when declared by our board of directors. Subject and subordinate to the prior payment to the holders of our preferred shares ranking before common shares, in the event of our liquidation, dissolution or winding-up, whether voluntary or involuntary, or other distribution of our assets among our shareholders for the purposes of winding up our affairs, the holders of common shares are entitled to share pro rata in the distribution of our remaining property and assets. The holders of common shares have no preemptive, conversion rights or other subscription rights. There are no redemption or sinking fund provisions applicable to our common shares. There is no provision in our articles requiring the holders of common shares to contribute additional capital

 

or permitting or restricting the issuance of additional securities or any other material restrictions. The rights and privileges of the holders of common shares will be subject to and may be adversely affected by, the rights and privileges of the holders of any series of preferred shares that we may designate in the future or any other class or series of shares that may be created and that would rank senior to the common shares.

Preferred Shares.   Pursuant to our articles, we may issue preferred shares at any time and from time to time, in one or more series. Under our articles, we are authorized to issue, without shareholder approval, an unlimited number of preferred shares, issuable in one or more series, and, subject to the provisions of the Business Corporations Act (Québec), or the QBCA, having such designations, rights, privileges, restrictions and conditions, including dividend and voting rights and calculation methods, as our board of directors may determine, and such rights and privileges, including voting, dividend, asset distribution and return of capital rights, may be superior to those of the common shares. Any convertible preferred shares we may issue will be convertible into our common shares or exchangeable for our other securities. Conversion may be automatic, mandatory or at the holder’s option and would be at prescribed conversion rates.

If we sell any series of preferred shares under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred shares, as well as the qualifications, limitations or restrictions thereof, in the articles of amendment containing a description of such series. Before issuing a series of preferred shares, we will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, any articles and certificates of amendment that describe the terms of the series of preferred shares that we are offering. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred shares being offered, as well as the complete articles and certificates of amendment that contain the terms of the applicable series of preferred shares.

Debt Securities.   We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common shares or other securities. Conversion may be automatic, mandatory or at the holder’s option and would be at prescribed conversion rates.

The debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. A form of indenture has been filed as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants.   We may issue warrants for the purchase of common shares, preferred shares and/or debt securities in one or more series. We may issue warrants independently or together with common shares, preferred shares and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. Forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental warrant agreements and forms of warrant certificates will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

 

We will evidence each series of warrants by warrant certificates that we will issue. Warrants may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

 

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