Gilead Presents New Data on Twice-Yearly Lenacapavir (Yeztugo®) for HIV Prevention at IAS 2025

– New Data from PURPOSE Trials Further Demonstrate that Lenacapavir (Yeztugo^®) was Effective and Well Tolerated Across a Broad Range of Populations, Including Pregnant and Lactating Women, Adolescents and Young People –

– Data Also Showed Twice-Yearly Injectable PrEP was Preferred vs. Daily Oral Medication Among PURPOSE Trial Participants –

– Gilead's Research Presentations and Community Events at IAS Reflect Commitment to Partnerships in Developing Person-Centered Options for a Diverse Range of Populations –

Gilead Sciences, Inc. (NASDAQ:GILD) today announced that Gilead researchers and collaborators will present new Phase 3 PURPOSE trial data at IAS 2025 showing that twice-yearly lenacapavir (Yeztugo^®) was effective and well tolerated among a broad range of populations who need or want pre-exposure prophylaxis (PrEP) for HIV prevention, including pregnant and lactating women, adolescents and young people, and supports lenacapavir dosing recommendations for people in special situations, such as those taking medication to treat tuberculosis (TB) and other conditions. Researchers will also present new quantitative and qualitative data showing that participants in both Phase 3 PURPOSE trials indicated a preference for twice-yearly PrEP injections over daily oral medication.

The new data, from the company's pivotal Phase 3 PURPOSE 1 (NCT04994509) and PURPOSE 2 (NCT04925752) trials that assessed the efficacy and safety of twice-yearly Yeztugo for PrEP, will be presented via poster sessions and during a Yeztugo-dedicated oral session at the International AIDS Society (IAS) 2025, the 13^th IAS Conference on HIV Science in Kigali, Rwanda on Thursday, July 17. The data presentations come less than a month after the U.S. Food and Drug Administration (FDA) approved Yeztugo as the first and only twice-yearly HIV prevention option. The data underscore Gilead's focus on intentional inclusion in the PURPOSE program to ensure broad and robust population data at the trials' primary analyses, as well as spotlight the community and organizational collaborations that guided the trial design and implementation process.

"It's a thrill to be back in Kigali with so many of the community, advocacy and research partners who helped make PURPOSE the most intentionally inclusive HIV prevention trial program ever conducted," said Moupali Das, Vice President of Clinical Development, HIV Prevention & Pediatrics at Gilead Sciences. "As the first and only twice-yearly PrEP option, Yeztugo continues to demonstrate efficacy and tolerability among diverse populations, and we're excited to highlight new data on this breakthrough HIV prevention option here at IAS 2025."

Yeztugo was Efficacious and Well Tolerated in Trials Among Pregnant and Lactating Women, Adolescents and Young People, and Can Be Administered in People Receiving Treatment for TB and Other Conditions

Pregnant and lactating women—who face a heightened likelihood of acquiring HIV—have historically been excluded from HIV prevention trials. Based on input from community meetings in locations including Kigali, Gilead ensured that pregnant and lactating women were included in the Phase 3 PURPOSE 1 trial, which evaluated twice-yearly Yeztugo in cisgender women and adolescent girls in Sub-Saharan Africa. PURPOSE data presented at IAS 2025 show that Yeztugo was efficacious in pregnant and breastfeeding or lactating women, with no new cases of HIV reported among 184 participants in the Yeztugo group (there were a total of 509 pregnancies among 487 participants in PURPOSE 1). Data also show that Yeztugo was well tolerated by these women, that there were similar safety profiles between pregnant and non-pregnant women, and that there were no clinically significant differences in predicted Yeztugo exposure by pregnancy trimester or postpartum status. Additionally, exposure in breastfed infants was minimal.

Young people aged 16-25 years are also at an increased likelihood of experiencing HIV acquisition globally, but, like pregnant women, are often not proactively included in Phase 3 HIV prevention trials. Gilead intentionally included this population in the PURPOSE 1 trial and the PURPOSE 2 trial, which evaluated twice-yearly Yeztugo among a broad and geographically diverse range of cisgender men and gender-diverse people. Data presented at IAS 2025 show that Yeztugo was efficacious in people aged 16-25 years, with zero reported HIV infections in young people receiving Yeztugo in PURPOSE 1 and two HIV infections among young people in PURPOSE 2. Additionally, there were no clinically significant pharmacokinetic differences between the 16-25-year-old group and adults aged over 25 years. Yeztugo was well tolerated across both trials among participants of all ages, with no new safety concerns identified.

Globally, those at higher likelihood of HIV acquisition may also be vulnerable to TB, which can be treated by rifamycin-class drugs including rifampin and rifabutin. Yeztugo is a substrate of CYP3A, and strong CYP3A inducers such as rifampin, or moderate inducers such as rifabutin, may potentially lower Yeztugo plasma concentrations. Gilead will present modeling data showing supplemental Yeztugo dosing for strong and moderate CYP3A inducers to allow people receiving Yeztugo to receive rifamycin-containing TB treatment, if necessary. Yeztugo is also a moderate inhibitor of CYP3A and could theoretically increase levels of drugs such as statins for lowering cholesterol or PDE5 inhibitors for treating erectile dysfunction; dosing recommendations for these special situations will also be reviewed.

Preference for Twice-Yearly Prevention Option Over Daily Oral PrEP

New qualitative and quantitative self-reported data from PURPOSE 1 and PURPOSE 2 show significant preference for twice-yearly injectable PrEP compared with daily oral PrEP among study participants. More than 75% of study participants who were surveyed preferred twice-yearly injectable administration; of these, more than 50% reported a strong preference. Reasons given for favoring twice-yearly injectable PrEP versus daily oral PrEP include feeling more protected from HIV (69%) and feeling more confident about not missing a dose (77%).

"Certain groups—including pregnant and lactating women, adolescents and young people—are disproportionately affected by HIV, yet have long been underrepresented in HIV clinical trials," said Linda-Gail Bekker, MBChB, DTM&H, DCH, FCP(SA), PhD, Director of the Desmond Tutu HIV Center at the University of Cape Town, South Africa, and former President of the International AIDS Society. "The PURPOSE program set a new standard for innovative, intentional inclusion by ensuring we would have safety and efficacy data in these populations from the outset. The results not only show that Yeztugo provides strong protection against HIV and was well tolerated in these groups, but also highlight the critical need for PrEP options that reflect people's preferences—reducing barriers to uptake and helping close persistent gaps in prevention."

Continued Global Regulatory Filings for Lenacapavir for PrEP, as Well as Milestone Partnerships

On June 18, 2025, Gilead received FDA approval for Yeztugo as PrEP to reduce the risk of sexually acquired HIV in adults and adolescents weighing at least 35kg. Gilead has also submitted a marketing authorization application (MAA) and EU-Medicines for all (EU-M4all) application with the European Medicines Agency (EMA), both of which the EMA has validated and will review under an accelerated assessment timeline. Gilead has also filed for regulatory approval for twice-yearly lenacapavir for PrEP with authorities in Australia, Brazil, Canada, South Africa and Switzerland. Additionally, now that lenacapavir has received FDA approval for PrEP, Gilead is preparing additional filings in countries that rely on stringent regulatory authority approvals for regulatory submission, including Argentina, Mexico and Peru. Gilead will continue to share updates on additional regulatory filings. Lenacapavir for HIV prevention is not approved by any regulatory authority outside of the United States.

Last week, Gilead announced a strategic partnership agreement with The Global Fund to Fight AIDS, Tuberculosis and Malaria to supply enough doses of lenacapavir, at no profit to Gilead, to reach up to two million people over three years in countries supported by the Global Fund and that are included in Gilead's voluntary licensing agreements for lenacapavir.

There is currently no cure for HIV or AIDS.

Please see below for U.S. Indication and Important Safety Information, including Boxed Warning, for Yeztugo.

About the PURPOSE Program

Gilead's landmark PURPOSE program is the most comprehensive and diverse HIV prevention trial program ever conducted. The program comprises five HIV prevention trials around the world that are focused on innovation in science, trial design, community engagement and health equity.

The PURPOSE trials are evaluating the safety and efficacy of the, twice-yearly injectable medicine, lenacapavir, to reduce the chance of getting HIV. The Phase 2 and 3 program, consisting of PURPOSE 1-5, is assessing the potential of lenacapavir to help a diverse range of people around the world who could benefit from PrEP.

More information about the PURPOSE program, including individual trial descriptions, populations and locations, can be found at www.purposestudies.com.

About Lenacapavir

Lenacapavir is approved in multiple countries for the treatment of multi-drug-resistant HIV in adults, in combination with other antiretrovirals. Lenacapavir is also approved in the United States to reduce the risk of sexually acquired HIV in adults and adolescents weighing at least 35kg who are at risk of HIV acquisition.

The multi-stage mechanism of action of lenacapavir is distinguishable from other currently approved classes of antiviral agents. While most antivirals act on just one stage of viral replication, lenacapavir is designed to inhibit HIV at multiple stages of its lifecycle and has no known cross resistance exhibited in vitro to other existing drug classes.

Lenacapavir is being evaluated as a long-acting option in multiple ongoing and planned early and late-stage clinical studies in Gilead's HIV prevention and treatment research program. Lenacapavir is being developed as a foundation for potential future HIV therapies with the goal of offering both long-acting oral and injectable options with several dosing frequencies, in combination or as a mono agent, that help address individual needs and preferences of people and communities affected by HIV. The journal Science named lenacapavir its 2024 "Breakthrough of the Year."

U.S. Indication for Yeztugo

Yeztugo (lenacapavir) injection, 463.5 mg/1.5 mL, is indicated for pre‑exposure prophylaxis (PrEP) to reduce the risk of sexually acquired HIV-1 in adults and adolescents (>35kg) who are at risk for HIV-1 acquisition. Individuals must have a negative HIV-1 test prior to initiating Yeztugo.

U.S. Important Safety Information for Yeztugo

BOXED WARNING: RISK OF DRUG RESISTANCE WITH USE OF YEZTUGO IN UNDIAGNOSED HIV-1 INFECTION

• Individuals must be tested for HIV-1 infection prior to initiating Yeztugo, and with each subsequent injection of Yeztugo, using a test approved or cleared by the FDA for the diagnosis of acute or primary HIV-1 infection. Drug-resistant HIV-1 variants have been identified with use of Yeztugo by individuals with undiagnosed HIV-1 infection. Do not initiate Yeztugo unless negative infection status is confirmed. Individuals who acquire HIV-1 while receiving Yeztugo must transition to a complete HIV-1 treatment regimen.

Contraindications

• Yeztugo is contraindicated in individuals with unknown or positive HIV-1 status.

Warnings and precautions

• Comprehensive risk management:
  • Use Yeztugo to reduce the risk of HIV-1 acquisition as part of a comprehensive prevention strategy including adherence to the administration schedule and safer sex practices, including condoms, to reduce the risk of sexually transmitted infections (STIs).
  • HIV-1 acquisition risk includes behavioral, biological, or epidemiologic factors including, but not limited to, condomless sex, past or present STIs, self-identified HIV risk, having sexual partners of unknown HIV-1 viremic status, or sexual activity in a high-prevalence area or network. Counsel individuals on the use of other prevention methods to help reduce their risk.
  • Use Yeztugo only in individuals confirmed to be HIV-1 negative. Evaluate for current or recent signs or symptoms consistent with HIV-1 infection. Confirm HIV-1 negative status prior to initiating, prior to each subsequent injection, and as clinically appropriate.
• Potential risk of resistance:
  • There is a potential risk of developing resistance to Yeztugo if an individual acquires HIV-1 before or when receiving Yeztugo, or following discontinuation. HIV- 1 resistance substitutions may emerge in individuals with undiagnosed HIV-1 infection taking only Yeztugo, because Yeztugo alone is not a complete regimen for HIV-1 treatment.
  • To minimize this risk, it is essential to test before each injection and additionally as clinically appropriate. Individuals confirmed to have HIV-1 must immediately begin a complete HIV-1 treatment regimen.
  • Alternative forms of PrEP should be considered after discontinuation of Yeztugo for those who are at continuing risk of HIV-1 acquisition and should be initiated within 28 weeks of the last Yeztugo injection.
• Long-acting properties and potential associated risks:
  • Residual concentrations of Yeztugo may remain in systemic circulation for up to 12 months or longer after the last injection.
  • Select individuals who agree to the required injection dosing schedule because nonadherence or missed doses could lead to HIV-1 acquisition and development of resistance.
• Serious injection site reactions: Improper administration (intradermal injection) has been associated with serious injection site reactions, including necrosis and ulcer. Only administer Yeztugo subcutaneously.

Adverse reactions

• Most common adverse reactions (≥5%) in Yeztugo clinical trials were injection site reactions, headache, and nausea.

Drug interactions

• Strong or moderate CYP3A inducers may significantly decrease Yeztugo concentrations. Dosage modifications are recommended when initiating these inducers.
• It is not recommended to use Yeztugo with combined P-gp, UGT1A1, and strong CYP3A inhibitors.
• Coadministration of Yeztugo with sensitive substrates of CYP3A or P-gp may increase their concentrations and result in the increased risk of their adverse events. Yeztugo may increase the exposure of drugs primarily metabolized by CYP3A initiated within 9 months after the last injection of Yeztugo.

Dosage and administration

• HIV screening: Test for HIV-1 infection prior to initiating, prior to each subsequent injection, and as clinically appropriate using an approved or cleared test for the diagnosis of acute or primary HIV-1 infection.
• Dosage: Initiation dosing (injections and tablets) followed by once-every-6-months continuation injection dosing. Tablets may be taken with or without food.
  • Initiation: Day 1: 927 mg by subcutaneous injection (2 x 1.5-mL injections) and 600 mg orally (2 x 300-mg tablets). Day 2: 600 mg orally.
  • Continuation: 927 mg by subcutaneous injection every 6 months (26 weeks) from date of last injection ±2 weeks.
• Anticipated delayed injections: If scheduled 6-month injection is anticipated to be delayed by more than 2 weeks, Yeztugo tablets may be taken on an interim basis (for up to 6 months) until injections resume. Dosage is 300 mg orally (1 x 300-mg tablet) once every 7 days. Resume continuation injections within 7 days of the last oral dose.
• Missed injections: If more than 28 weeks have elapsed since the last injection and Yeztugo tablets have not been taken, restart with initiation dosing if clinically appropriate.
• Dosage modifications of Yeztugo are recommended when initiating with strong or moderate CYP3A inducers. Consult the full Prescribing Information for recommendations.

About Gilead HIV

For more than 35 years, Gilead has been a leading innovator in the field of HIV, driving advances in treatment, prevention and cure research. Gilead researchers have developed 13 HIV medications, including the first single-tablet regimen to treat HIV, the first antiretroviral for pre-exposure prophylaxis (PrEP) to help reduce new HIV infections, and the first long-acting injectable HIV treatment medication administered twice-yearly. Our advances in medical research have helped to transform HIV into a treatable, preventable, chronic condition for millions of people.

Gilead is committed to continued scientific innovation to provide solutions for the evolving needs of people affected by HIV around the world. Through partnerships, collaborations and charitable giving, the company also aims to improve education, expand access and address barriers to care, with the goal of ending the HIV epidemic for everyone, everywhere. Gilead has been recognized as one of the leading philanthropic funders of HIV-related programs in a report released by Funders Concerned About AIDS.

About Gilead Sciences

Gilead Sciences, Inc. is a biopharmaceutical company that has pursued and achieved breakthroughs in medicine for more than three decades, with the goal of creating a healthier world for all people. The company is committed to advancing innovative medicines to prevent and treat life-threatening diseases, including HIV, viral hepatitis, COVID-19, cancer and inflammation. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, California.

Forward-Looking Statements

This press release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks, uncertainties and other factors, including Gilead's ability to realize the anticipated benefits from the collaboration; difficulties or unanticipated expenses in connection with the collaboration and the potential effects on Gilead's earnings; Gilead's ability to initiate, progress and complete clinical trials in the anticipated timelines or at all, and the possibility of unfavorable results from ongoing and additional clinical trials, including those involving Yeztugo (lenacapavir) (such as PURPOSE 1 and PURPOSE 2); uncertainties relating to regulatory applications and related filing and approval timelines, including regulatory applications for lenacapavir for PrEP, and the risk that any regulatory approvals, if granted, may be subject to significant limitations on use or subject to withdrawal or other adverse actions by the applicable regulatory authority; the possibility that Gilead may make a strategic decision to discontinue development of lenacapavir for indications currently under evaluation and, as a result, lenacapavir may never be successfully commercialized for such indications; the risk that physicians may not see the benefits of prescribing Yeztugo; Gilead's ability to effectively manage the access strategy relating to lenacapavir, subject to necessary regulatory approvals; and any assumptions underlying any of the foregoing. These and other risks, uncertainties and factors are described in detail in Gilead's Quarterly Report on Form 10-Q for the quarter ended March 31, 2025, as filed with the U.S. Securities and Exchange Commission. These risks, uncertainties and other factors could cause actual results to differ materially from those referred to in the forward-looking statements. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. The reader is cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties and is cautioned not to place undue reliance on these forward-looking statements. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation and disclaims any intent to update any such forward-looking statements.

U.S. full Prescribing Information for Yeztugo, including Boxed Warning, is available at www.gilead.com.

Gilead and the Gilead logo, and Yeztugo are registered trademarks of Gilead Sciences, Inc., or its related companies.

For more information about Gilead, please visit the company's website at www.gilead.com, follow Gilead on X/Twitter (@Gilead Sciences) and LinkedIn (@Gilead-Sciences).

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Ashleigh Koss, Media

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Jacquie Ross, Investors

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