The FDA approved Merck & Co.’s Idvynso (doravirine/islatravir), a once-daily two-drug HIV regimen for adults with HIV-1 who are virologically suppressed and meet specific resistance criteria. The approval arrives with a new prescribing option for patients who need switching due to safety or tolerability issues. For Merck, the nod is positioned as a strategic step in rebuilding momentum after a period of heightened market competition in HIV. It also increases pressure on entrenched regimens by widening the set of combination options for clinicians. The approval timing—just ahead of a stated PDUFA date—underscores how quickly Merck can convert regulatory engagement into market access.