Merck and Gilead Sciences announced on June 9 a combination of positive Phase 3 results for their weekly HIV pill and disappointing late-stage data for their lung cancer treatment. The companies reported that their investigational single-tablet combination of islatravir and lenacapavir (IS/LEN) could become the first long-acting oral HIV treatment, potentially strengthening both companies' positions in the market.
BMO Capital Markets described the day as “sweet and sour” in a Monday evening note. On the positive side, BMO said, “the latest readout could establish the investigational drug—a single-tablet combo of islatravir and lenacapavir (IS/LEN)—as ‘the first long-acting oral HIV treatment, strengthening Gilead/Merck’s positioning in the market.’”
The Phase 3 ISLEND-1 and ISLEND-2 studies tested this combination pill in patients with HIV who had already achieved virological suppression through either Gilead’s Biktarvy or other standard antiretroviral therapies. After 48 weeks, results showed that IS/LEN was non-inferior to existing treatments at maintaining virological suppression. BMO called this outcome “incrementally positive,” adding that IS/LEN could appeal to patients seeking less frequent oral dosing options. The analysts also said, “Gilead continues to stay ahead of the HIV treatment curve.” For Merck, BMO said these findings may help it become “a more meaningful competitor in HIV as the company aims to strengthen its presence in the indication.”
Despite these promising results for HIV therapy, Merck and Gilead faced setbacks with their investigational regimen combining Trodelvy—an antibody-drug conjugate from Gilead—and Keytruda—Merck’s PD-1 inhibitor—in metastatic non-small cell lung cancer (NSCLC). The companies discontinued the Phase 3 KEYNOTE-D46 trial after an independent data board found only a numerical improvement in progression-free survival compared with Keytruda alone; this difference did not reach statistical significance. The committee indicated it was unlikely that significant overall survival improvements would be observed at final analysis.
BMO said this outcome “adds to challenging misses for Trodelvy,” especially since success would have supported accelerated revenue growth for that product line. Trodelvy previously failed another Phase 3 study in NSCLC in January 2024.
