Merck to submit once-daily version of HIV drug Isentress

Merck has unveiled phase 3 results of its HIV drug Isentress, which shows that a once-daily form of the drug was as good as its existing twice-daily dosage.

Launched in 2007, Merck's Isentress (realtegravir) was the first integrase inhibitor (INI) to be approved and, and has been popular with doctors and patients because of its tolerability and efficacy. But the drug is losing out to newer once-daily INI drugs, most notably ViiV's Tivicay (dolutegravir).

Merck is now following suit with Isentress, and is looking to file it with regulators soon.

The ONCEMRK trial is evaluating a once-daily formulation of Isentress, known as raltegravir 600 mg (to be given as 2 x 600 mg once-daily), for previously untreated HIV-1 infected adults. The study met its primary efficacy endpoint: 1200 mg raltegravir (given as 2 x 600 mg once-daily) was statistically non-inferior to the marketed formulation approved dose of Isentress 400 mg twice-daily, each in combination therapy with Gilead's Truvada, as assessed by the proportion of patients achieving HIV-1 RNA <40 copies/mL at Week 48.

The firm also reported that secondary endpoints of tolerability and immunologic efficacy (as measured by change from baseline in CD4 cell counts at Week 48) were comparable.

Merck plans to present details of the study at an upcoming scientific conference, and to submit marketing applications to the U.S. Food and Drug Administration and the European Medicines Agency for the new formulation.

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