Positive Phase III data for Merck's doravirine/islatravir in people with HIV-1 infection

US pharma giant Merck& Co (NYSE: MRK) yesterday announced positive top-line results from two pivotal Phase III 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 II studies. Doravirine is approved under the trade name Pifeltro, for the treatment of adults with HIV-1 in combination with other antiretrovirals, as a single agent and a component of a single-tablet regimen (Delstrigo; DOR/3TC/TDF).