Looking at an Investigational PrEP Treatment With an Implant Option

Merck’s islatravir (formerly MK-8591) is an investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI) being studied for both PrEP and HIV therapy. With regards to PrEP, the company is planning to study its islatravir subdermal implant for the possibility of 1 year of therapy.

"I think a yearly implant will be an attractive option for many people,” trial investigator Randolph Matthews, MD, PhD, senior principal scientist, Merck, said. “We are looking at a scenario over the next several years where people who are interested in PrEP, will have several different options.”

He says the therapy has a high potency and long half-life which makes it possible to look at long-term delivery.

Earlier today, Merck reported results from its phase 1 trial of its islatravir subdermal implant for HIV prevention. It was a double-blind placebo-controlled multicenter phase 1 trial, studying a single islatravir-eluting (48 mg, 52 mg or 56 mg) or placebo implant, which was placed in participants at low risk of HIV infection for 12 weeks.

The company said the investigational therapy demonstrated that the implant achieved active drug concentrations above the pre-specified pharmacokinetics (pk) threshold at 12 weeks across the three doses of islatravir studied (48 mg, 52 mg and 56 mg).

Safety and tolerability, as well as PK for islatravir parent and islatravir-TP from plasma and PBMCs, was collected throughout placement and for 8 weeks post removal.

The data was presented during the Conference on Retroviruses and Opportunistic Infections (CROI) 2021 virtual sessions.

In this second segment of an interview with Contagion, Matthews talks about PrEP treatment options and what they are doing to get ready for a phase 2 trial.