Merck reported that its once-daily two-drug islatravir combination was non-inferior to a three-drug regimen in a Phase 3 study, marking another clinical success in the company’s effort to expand its HIV portfolio. The result supports islatravir as a potential new backbone therapy for treatment-naïve or switch patients and strengthens Merck’s competitive positioning against existing standards of care. Merck has been incrementally building an HIV franchise; the islatravir data reduce clinical risk and may accelerate regulatory filing strategies. Competitors and payers will evaluate the regimen’s tolerability, resistance profile, and convenience attributes relative to entrenched products. For clinicians, the two-drug approach could simplify long-term HIV management if approved, while commercial teams will need to map out differentiation versus established three-drug regimens.