By Chris Wack


Merck & Co. said Tuesday it will begin a new Phase 3 clinical program with once-daily islatravir for the treatment of people with HIV-1 infection.

The company said these new Phase 3 studies will evaluate a once-daily oral combination of doravirine 100 mg and a lower dose of islatravir, known as DOR/ISL.

One study will evaluate DOR/ISL in previously untreated adults with HIV-1 infection, and two studies will evaluate DOR/ISL as a switch in antiretroviral therapy in adults with HIV-1 infection who are virologically suppressed, the company said.

Certain study participants currently enrolled in once-daily treatment studies with DOR 100 mg/ISL 0.75 mg will have the option of transitioning to a new study with the lower islatravir dose, it said.

The U.S. Food and Drug Administration has reviewed and agreed with this plan. The investigational new-drug application for the once-daily oral DOR/ISL treatment program remains under a partial clinical hold for any studies that would use doses higher than the dose to be studied in the new Phase 3 program, the company said.

Merck said it will discontinue the development of once-monthly oral islatravir for pre-exposure prophylaxis. Participants in the ongoing Phase 3 PrEP once-monthly oral studies will continue to be monitored. A Phase 1b study in adults with HIV-1 infection assessing MK-8527, a novel nucleoside reverse transcriptase translocation inhibitor, or NRTTI, candidate, will begin soon, the company said.

Merck also said the Phase 2 clinical trial evaluating an investigational oral once-weekly combination treatment regimen of islatravir and Gilead Sciences Inc.'s lenacapavir in adults with HIV-1 infection who are virologically suppressed will resume under an amended protocol with a lower dose of islatravir.

The IND under which the islatravir-plus-lenacapavir once-weekly treatment regimen is being investigated remains under a partial clinical hold for any studies that would use weekly oral islatravir doses higher than the doses considered for the revised clinical program, the company said.


Write to Chris Wack at chris.wack@wsj.com


(END) Dow Jones Newswires

09-20-22 0727ET