Merck (MSD) has reported data from a Phase IIa trial that showed an encouraging safety and tolerability profile of oral medication islatravir for pre-exposure prophylaxis (PrEP) of human immunodeficiency virus-1 (HIV-1) infection in adults.
An experimental nucleoside reverse transcriptase translocation inhibitor, islatravir is currently being analysed, along with other antiretrovirals in HIV-1 trials.
The ongoing, randomised, double-blind, parallel assignment, placebo-controlled, multi-centre Phase IIa trial assessed the safety, tolerability and pharmacokinetics (PK) of islatravir for HIV-1 PrEP in adults who are at reduced risk for contracting the disease.
For the study, 242 subjects were enrolled and randomised in a 2:2:1 ratio to receive once-monthly doses of either islatravir 60mg, islatravir 120mg or a placebo for 24 weeks.
The trial will evaluate outcome measures for safety, tolerability and PK till week 68.
Data from the trial showed that a once-monthly dose of islatravir was generally well tolerated against placebo following 24 weeks of treatment.
The majority of adverse events (AEs) in the trial were mild, with headache, diarrhoea and nausea being the most common AEs. No serious AEs linked to the drug were reported so far.
Furthermore, the levels of islatravir in peripheral blood mononuclear cells were found to be above the pre-specified efficacy PK threshold for PrEP at 60mg and 120mg doses. These levels persisted through eight weeks from the last drug dose.
Merck Research Laboratories infectious diseases global clinical development vice-president Dr Joan Butterton said: “The 24-week analysis of investigational, once-monthly oral islatravir not only builds upon the PK data we have already seen but also provides encouraging support for the safety and tolerability profile of this HIV-1 PrEP regimen.
“As part of our commitment to understanding the potential for our HIV medicines in a broad range of patients, we focused on the enrolment of diverse patient populations at risk for HIV, including women, who have one of the highest unmet needs in HIV prevention.”
Last week, Merck reported that Phase III KEYNOTE-522 trial of Keytruda plus chemotherapy showed a statistically significant event-free survival in high-risk early-stage triple-negative breast cancer patients.