Merck HIV Drug Trials on Clinical Hold
FDA has placed clinical holds on Merck INDs for the oral and implant formulations of islatravir (MK-8591) for HIV-1 pre-exposure prophylaxis (PrEP); the injectable formulation of islatravir for HIV-1 treatment and prophylaxis; and the oral doravirine/islatravir (DOR/ISL) forulation for HIV-1 once-daily treatment. The agency’s actions are based on previously announced observations of decreases in total lymphocyte and CD4+ T-cell counts in some participants receiving islatravir in clinical studies, Merck says. As previously announced, Merck has stopped dosing in the Phase 2 IMAGINE-DR clinical trial of islatravir in combination with MK-8507 (MK-8591-013) and paused enrollment in the once-monthly Phase 3 PrEP studies, (MK-8591-022 and MK-8591-024).
Under FDA’s clinical hold, no new studies may be initiated, according to the company. Patients who are currently receiving islatravir as part of the studies for PrEP, including oral and implant formulations, as well as injectable islatravir for treatment and prophylaxis, will no longer receive the study drug. Merck also says CD4+ T-cell and total lymphocyte counts will be monitored to determine recovery, and participants in the PrEP studies will be offered approved, once-daily, oral PrEP. Additionally, patients in the DOR/ISL studies who were started on treatment will continue to receive study medication (partial clinical hold).