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Gilead Announces Clinical Hold on Studies Evaluating Injectable Lenacapavir for HIV Treatment and Prevention Due to Vial Quality Concerns

-- Pause Due to Concerns About Compatibility of the Vial Type with the Drug Solution --

Gilead Sciences, Inc. (Nasdaq: GILD) today announced that the U.S. Food and Drug Administration (FDA) has placed a clinical hold on the use of injectable lenacapavir in borosilicate vials in all ongoing clinical studies for HIV treatment and HIV pre-exposure prophylaxis (PrEP). The FDA’s clinical hold is due to emerging concerns about the compatibility of vials made of borosilicate glass with lenacapavir solution, which could potentially lead to the formation of sub-visible glass particles in the solution of lenacapavir. Dosing of oral formulations of lenacapavir will continue. The company remains confident about the future potential of lenacapavir and is committed to resolving this vial quality issue.

During the clinical hold, screening and enrollment of study participants and the dosing of injectable lenacapavir will not be permitted across all lenacapavir studies. All other study activities, including the monitoring of participants and the dosing of participants in comparator arms, will continue according to the relevant study protocol.

“We are committed to working diligently with FDA to resolve this glass vial compatibility quality issue and resume injectable lenacapavir dosing in the affected studies in a timely fashion,” said Merdad Parsey, MD, PhD, Chief Medical Officer, Gilead Sciences.

The following studies have been placed on clinical hold:






Phase 2/3

(NCT 04150068)

A Phase 2/3 Study to Evaluate the Safety and Efficacy of Long Acting Capsid Inhibitor GS-6207 in Combination with an Optimized Background Regimen in Heavily Treatment Experienced People Living With HIV-1 Infection with Multidrug Resistance


Phase 2

(NCT 04143594)

A Phase 2 Randomized, Open Label, Active Controlled Study Evaluating the Safety and Efficacy of Long-acting Capsid Inhibitor GS-6207 in Combination with Other Antiretroviral Agents in People Living with HIV


Phase 1

A Phase 1 Study in Healthy Participants to Evaluate the Safety, Tolerability, and Pharmacokinetics of Lenacapavir (LEN)


Phase 3

(NCT 04994509)

A Phase 3, Double-Blinded, Multicenter, Randomized Study to Evaluate Safety and Efficacy of Twice Yearly Long-Acting Subcutaneous Lenacapavir, and Daily Oral Emtricitabine/Tenofovir Alafenamide for Pre-Exposure Prophylaxis in Adolescent Girls and Young Women at Risk of HIV Infection (PURPOSE-1)


Phase 3

(NCT 04925752)

A Phase 3, Double-Blind, Multicenter, Randomized Study to Evaluate the Efficacy and Safety of Subcutaneous Twice Yearly Long-Acting Lenacapavir for HIV Pre-Exposure Prophylaxis in Cisgender Men, Transgender Women, Transgender Men, and Gender Non-binary People ≥ 16 Years of Age Who Have Sex With Partners Assigned Male at Birth and Are at Risk for HIV Infection


Phase 1b

(NCT 04811040)

A Phase 1b Randomized, Blinded, Proof-of-Concept Study to Evaluate the Safety and Efficacy of Broadly Neutralizing Antibodies (bNAbs) GS-5423 and GS-2872 in Combination with Capsid Inhibitor Lenacapavir (GS-6207) in Virologically Suppressed Adults with HIV-1 Infection


Phase 1

A Phase 1 Study in Healthy Participants to Evaluate the Safety, Tolerability, and Pharmacokinetics of Subcutaneous and Intramuscular Lenacapavir


Phase 1

A Phase 1 Study in Healthy Participants to Evaluate the Safety, Tolerability, and Pharmacokinetics of Subcutaneous and Intramuscular Lenacapavir


Phase 1

A Phase 1, Open-Label, Single-Arm, Single-Dose Study to Evaluate the Pharmacokinetics and Distribution of Long-Acting HIV Capsid Inhibitor, Lenacapavir (LEN), into Rectal and Female Genital Tract Tissues in HIV-Seronegative Participants


Phase 1

A Phase 1 Study to Evaluate the Effect of Subcutaneous (SC) Injection Sites on the Pharmacokinetics (PK) of Lenacapavir (LEN)

Lenacapavir is an investigational compound and is not approved by any regulatory authority for any use and its safety and efficacy are not known. There is no cure for HIV or AIDS.

About Lenacapavir

Lenacapavir is Gilead’s potential first-in-class, investigational long-acting HIV-1 capsid inhibitor in development for the treatment and prevention of HIV-1 infection. Lenacapavir's multi-stage mechanism of action is distinguishable from currently approved classes of antiviral agents and is designed to provide a new avenue for the development of long-acting therapy options for people living with or at risk for HIV-1. While most antivirals act on just one stage of viral replication, lenacapavir is designed to inhibit HIV-1 at multiple stages of its lifecycle.

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 and cancer.

For more than 30 years, Gilead has been a leading innovator in the field of HIV, driving advances in treatment, prevention and cure research. Gilead researchers have developed 11 HIV medications, including the first single tablet regimen to treat HIV and the first antiretroviral for pre-exposure prophylaxis (PrEP) to reduce the risk of acquiring HIV infection. These advances in medical research have helped to transform HIV into a 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 and collaborations, 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 operates in more than 35 countries worldwide, with headquarters in Foster City, California.

Forward-Looking Statements

This statement 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 initiate, progress and complete clinical trials involving the injectable formulation of lenacapavir for HIV treatment and PrEP in the anticipated timelines or at all; the possibility of unfavorable results from ongoing and additional clinical trials involving lenacapavir; uncertainties relating to regulatory applications and related filing and approval timelines, including the risk that FDA may not remove the clinical holds on the INDs for the injectable formulation of lenacapavir for HIV treatment and PrEP; the possibility that Gilead may make a strategic decision to discontinue development of lenacapavir and as a result, lenacapavir may never be successfully commercialized; 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 September 30, 2021, 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 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.

For more information about Gilead, please visit the company’s website at, follow Gilead on Twitter (@Gilead Sciences) or call Gilead Public Affairs at 1-800-GILEAD-5 or 1-650-574-3000.


Jacquie Ross, Investors

(408) 656-8793

Mark Snyder, Media

(650) 450-2480

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