FDA Halts 10 Gilead Lenacapavir HIV Trials Over Glass Particulate Concerns

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Following Merck's islatravir, another investigational HIV drug has been placed on clinical hold by the U.S. FDA—this time from Gilead Sciences. However, some analysts have pointed out that the situation with Gilead’s HIV drug lenacapavir is different. Its clinical hold is due to a quality issue that can be quickly resolved, whereas the clinical hold for Merck's islatravir was related to a decrease in patients' immune cell counts.

On December 22, Gilead Sciences announced that the U.S. FDA has placed a clinical hold on up to 10 clinical trials of its injectable HIV candidate drug lenacapavir due to concerns about the compatibility between the drug solution and the borosilicate glass vials used for storage. There is a possibility that the borosilicate glass vials could interact with the drug solution, resulting in "sub-visible" glass particles forming in the lenacapavir solution.

Gilead Chief Medical Officer Merdad Parsey said in a statement that this clinical hold does not involve the oral lenacapavir clinical trials. Regarding the injectable formulation, Gilead remains confident in the drug's future and is committed to resolving the vial quality issue promptly.

Gilead further stated in its announcement that during the clinical hold, no screening or enrollment of study participants will be allowed in any lenacapavir studies, and no injections of lenacapavir will be permitted. All other study activities, including monitoring participants and administering doses to the control group, will continue as per the relevant study protocols.

The Scope of Affected Clinical Trials for Injectable Lenacapavir Ranges from Early to Late Stages of Development, Including Two Phase 3 Trials, Both Currently on Hold. In a report to clients on Wednesday, RBC Capital Markets analyst Brian Abrahams wrote that while this news is undoubtedly a "setback," there are reasons to believe Gilead Sciences may soon get its injectable lenacapavir program back on track.

Brian Abrahams pointed out that, first of all, most of the suspended research was in the early stages and only represented a "small" market opportunity. "Even if the dose is skipped... it will produce interpretable results." The exceptions are two Phase 3 pre-exposure prophylaxis (PrEP) studies.

At the same time, in the later-stage research, injectable lenacapavir was administered once every six months. This means that Gilead Sciences can address the vial issue quickly enough to avoid offering alternative treatments to many patients.

Merck's situation is obviously worse. Last week, the U.S. FDA placed a clinical hold on 13 clinical trials of islatravir. Among these 13 clinical trials, 7 were Phase III clinical trials, and this clinical hold was a significant blow to the islatravir program. The FDA's decision was based on concerns about decreased white blood cell counts in patients taking islatravir, rather than quality issues like those at Gilead Sciences. [Related reading:FDA Places Hold on Merck's HIV Drug Islatravir Oral and Implant Investigational New Drug Applications】

But it should be noted that this is not Gilead's first particle scare this month. Earlier in December, the company announced a recall of two batches of its COVID-19 antiviral drug Veklury (remdesivir) after customers complained of glass particles in the injection solution. The company said at the time that its own investigation had confirmed the complaint.

Gilead did not explain how glass particles appeared in the Veklury vials, and it is also unclear whether the issue with lenacapavir is related to this.

Reference Source: Particulate problem prompts hold on 10 Gilead studies of HIV hopeful lenacapavir