Merck Announces Positive Top-Line Results from Pivotal Phase 3 Trials Evaluating Investigational, Once-Daily Oral Fixed Dose Combination of Doravirine/Islatravir for the Treatment of People with HIV-1 Infection

Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced positive top-line results from two pivotal Phase 3 trials of the investigational, once-daily oral fixed dose combination pill of doravirine/islatravir (DOR/ISL) in adults with HIV-1 infection who are virologically suppressed on different antiretroviral therapy regimens (ART; ILLUMINATE SWITCH A) or bictegravir/emtricitabine/tenofovir (BIC/FTC/TAF; ILLUMINATE SWITCH B). At 48 weeks, both trials met their primary efficacy endpoint of percentage of participants with HIV-1 RNA levels ≥50 copies/mL, demonstrating that antiviral efficacy was comparable between DOR/ISL and ART (ILLUMINATE SWITCH A) and between DOR/ISL and BIC/FTC/TAF (ILLUMINATE SWITCH B). The safety and tolerability profile of DOR/ISL during the trials to date are consistent with the previously reported Phase 2 studies. Doravirine is approved for the treatment of adults with HIV-1 in combination with other antiretrovirals, as a single agent (PIFELTRO) and a component of a single-tablet regimen (DELSTRIGO; DOR/3TC/TDF). Islatravir is Merck’s investigational nucleoside reverse transcriptase translocation inhibitor under evaluation for the treatment of people living with HIV-1 infection in combination with other antiretrovirals. Detailed findings from these studies will be presented at a future scientific congress and will form the basis of global regulatory applications.

“Merck is committed to investigating potential treatment options to help address the evolving needs of people living with HIV,” said Dr. Joan Butterton, vice president, global clinical development, infectious diseases, Merck Research Laboratories. “We are encouraged by the results from the Phase 3 ILLUMINATE SWITCH A and B trials, in which the DOR/ISL dual regimen efficacy was comparable to certain commonly used three-drug regimens. We will continue to study doravirine/islatravir in diverse populations of people living with HIV and look forward to sharing data from these trials.”

The ILLUMINATE clinical trial program is evaluating DOR/ISL in a broad patient population, which includes people with HIV-1 who are virologically suppressed on ART, those who are heavily treatment experienced and those who are new to HIV treatment. The clinical trial program also includes pediatric participants with HIV-1 weighing at least 35 kg who are virologically suppressed and have not previously been treated. Merck is committed to enrolling diverse people in our HIV-1 clinical trials, especially among communities who may be disproportionately impacted by HIV, such as women and those within the Black and Latinx communities.