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US FDA approves Merck’s pill combo to treat HIV infection

By Thomson Reuters Apr 21, 2026 | 10:55 AM

By Christy Santhosh and Sriparna Roy

April 21 (Reuters) – The U.S. Food and Drug Administration has approved Merck’s once-daily, oral, combination regimen for HIV infections, the drugmaker said on ​Tuesday, giving patients another treatment option to manage the ‌condition.

The two-drug combination of doravirine and islatravir, branded as Idvynso, was approved to replace the current antiretroviral regimen for treating Human Immunodeficiency Virus-1 infection in some adults.

While islatravir is an experimental treatment, Merck’s doravirine is approved and ‌sold ​in the U.S. under the brand name ⁠Pifeltro for HIV-1 treatment ⁠in combination with other antiretrovirals, and as a single-tablet regimen, Delstrigo.

HIV-1 is the most common strain of the retrovirus that causes acquired immunodeficiency syndrome, commonly known as AIDS.

About 40.8 million ​people are living with HIV globally, and about 1.3 million new infections occur annually, according to National Institutes of Health ⁠data.

“Idvynso expands therapeutic diversity beyond the ⁠currently available oral treatment options,” said Dr. Eliav Barr, ​senior vice president and chief medical officer, Merck Research Laboratories.

In two ​late-stage studies with more than 1,000 patients, the treatment ‌combination met the main goal of significantly suppressing replication of HIV-1 in adults receiving another form of therapy.

Last year, Merck’s oral drug combination was found to be non-inferior to Gilead’s top-selling drug, ⁠Biktarvy, achieving similar HIV-1 suppression to the current standard of care.

While this is a meaningful developmental milestone for Merck, RBC Capital Markets analyst ⁠Trung Huynh expects ‌initial commercial impact to be limited, with the ⁠inflection point being a potential approval in patients ​who ‌have not received any treatment.

Merck’s HIV story is ​best viewed ⁠as a “multi-year build rather than a near-term growth driver,” said Huynh.

Islatravir is being tested in multiple trials in combination with other antiretrovirals for potential daily and once-weekly treatments for HIV-1.

(Reporting by Christy Santhosh and Sriparna Roy in Bengaluru; Editing by Sahal Muhammed, Shinjini Ganguli ​and Shilpi Majumdar)