The US Food and Drug Administration (FDA) has stopped trials of oral and implant formulations of islatravir for HIV, the investigational drug's developer, Merck and Co, announced in a press release.
Investigational new drug applications were halted for the oral and implant formulations of islatravir, a nucleoside reverse transcriptase translocation inhibitor, for pre-exposure prophylaxis (PrEP); the injectable formulation of islatravir for treatment and prophylaxis; and the oral doravirine/islatravir (DOR/ISL) once-daily treatment, the company announced this week.
The FDA's hold followed observations that total lymphocyte and T-cell counts had dropped in some participants receiving islatravir in clinical studies.
The trials have dealt a major setback to Merck's HIV program momentum: Thirteen trials are now on hold (six on partial hold and seven on full hold). Seven of the trials were in phase 3. But primarily the news is disappointing for patients looking for options with the confounding disease.
Dr Tristan Barber
Tristan Barber, MD, an HIV consultant with Royal Free London National Health Service Foundation Trust in London, England, told Medscape Medical News,"The hold on these studies is a blow for those hoping for longer-acting therapies for HIV treatment and prevention. Islatravir and [investigational drug] MK-8507 were being explored in oral and other formulations and potentially would offer a non-integrase, two-drug option, increasing options for people with HIV.
