10:00 AM EDT, 07/14/2025 (MT Newswires) -- Merck ( MRK ) said Monday it plans to start a program of phase 3 trials to evaluate the safety and efficacy of MK-8527, the company's investigational once-monthly oral nucleoside reverse transcriptase translocation inhibitor for HIV pre-exposure prophylaxis.

The company said the EXPrESSIVE-11 phase 3 trial will evaluate MK-8527 in "people with greater likelihood of HIV-1 exposure" in 16 countries and is expected to start enrollment in August.

Meanwhile, the EXPrESSIVE-10 phase 3 trial is a collaboration with the Gates Foundation and will evaluate MK-8527 in women and adolescent girls in sub-Saharan Africa, with enrollment targeted to start in the next few months, Merck ( MRK ) said.

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