While Merck and Gilead Sciences reported back-to-back late-stage victories for their weekly HIV pill, the partners also discontinued a Phase 3 program for their cancer combo after disappointing lung cancer survival data.
Monday was a mixed bag for Merck and Gilead Sciences, which notched key Phase 3 victories for their weekly HIV pill but reported disappointing late-stage data for their lung cancer combo.
“Sweet and sour,” BMO Capital Markets quipped in a Monday evening note. On the sweet side, 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.”
This win, however, may be “muted” by the failure of the investigational regimen comprising Gilead’s antibody-drug conjugate Trodelvy with Merck’s PD-1 blockbuster Keytruda to significantly improve survival in patients with metastatic non-small cell lung cancer (NSCLC).
On the HIV front, the pharma partners tested their single-pill drug combo in the Phase 3 ISLEND-1 and ISLEND-2 studies in patients with HIV who have been virologically suppressed either through Gilead’s Biktarvy or other standard-of-care antiretroviral therapies. At 48 weeks, the IS/LEN pill was non-inferior to Biktarvy or other standard regimens at maintaining virological suppression, according to a news release on Monday.
BMO called this outcome “incrementally positive,” but said that IS/LEN could help the companies—Gilead in particular—access the “subset of virally suppressed patients who would prefer less frequent oral options.” With these findings, the analysts added, “Gilead continues to stay ahead of the HIV treatment curve.”
For Merck, meanwhile, the ISLEND data could help the pharma establish itself “as a more meaningful competitor in HIV as the company aims to strengthen its presence in the indication,” BMO said.
The companies did not provide specific data in their press announcement but promised to do so at a future medical congress. Merck and Gilead will also file the ISLEND data to regulatory authorities globally.
The positive data in HIV could also help offset Gilead’s latest cancer blow.
Also on Monday, Merck and Gilead announced that they would be discontinuing the Phase 3 KEYNOTE-D46 trial (also known as EVOKE-03), studying a combo regimen of Trodelvy and Keytruda in NSCLC patients with PD-L1-positive tumors. An independent data board found a “numerical improvement” in progression-free survival, but compared with Keytruda monotherapy, this effect fell short of statistical significance.
The data committee also noted that it would be “unlikely” for the drug doublet to elicit significant overall survival improvements at the final analysis, prompting the companies to pull the plug on the program.
For Gilead, this outcome “adds to challenging misses for Trodelvy,” BMO said, especially in NSCLC, where a first-line approval “would have supported accelerated revenue growth for the product.” Trodely previously failed a Phase 3 study in this indication, unable to significantly boost overall survival versus docetaxel, according to a January 2024 readout.
Trodelvy grew 6% in 2025 to bring in $1.4 billion.
