Merck’s HIV Treatment Meets Main Goal in Two Late-stage Studies

(Reuters) -Merck’s experimental two-drug combination met the main goal of significantly suppressing replication of the HIV-1 virus in adults receiving another form of therapy in two late-stage studies, the company said on Thursday.

The U.S. drugmaker is seeking new growth drivers to offset a potential hit from its blockbuster cancer immunotherapy Keytruda losing patent protection toward the end of the decade.

Merck was testing a combination of doravirine and islatravir across the trials involving more than 1,000 patients.

In one of the studies, Merck’s combination was shown to be safe and “non-inferior” to Gilead Sciences’ top-selling HIV drug Biktarvy.

However, the treatment was not superior to Biktarvy in suppressing the replication of HIV-1, the most common strain of the virus, in the same study, which enrolled patients who were already receiving Gilead’s drug.

These patients were randomly chosen to either switch to Merck’s treatment or continue on Biktarvy.

In both the studies, Merck was testing its combination in patients who were already on antiretroviral therapy, which stops the virus from reproducing in the body.

Doravirine, branded as Pifeltro, is approved in combination with other antiretrovirals to treat adults with HIV-1 infection with no history of treatment failure or resistance to the drug.

It is also approved under the brand name Delstrigo as a single, complete regimen for the treatment of these patients.

The label for doravirine carries a boxed warning, the health regulator’s strictest, to flag the risk of worsening hepatitis B infection.

Merck’s combination also helped suppress viral replication in adults compared to other antiretroviral therapy in a separate open-label late-stage study.

The company plans to file the data with regulatory authorities and present detailed findings at a medical meeting.

(Reporting by Mariam Sunny in Bengaluru; Editing by Shilpi Majumdar and Sriraj Kalluvila)