Merck and Kelun‑Biotech announced that their TROP2‑directed antibody‑drug conjugate sacituzumab tirumotecan (sac‑TMT) met its primary endpoints in a global phase 3 trial for advanced or recurrent endometrial cancer. In the prespecified interim analysis, sac‑TMT delivered statistically significant and clinically meaningful gains in both overall and progression‑free survival compared with physician’s choice of doxorubicin or paclitaxel, also meeting a key secondary endpoint for objective response rate. The study enrolled 776 patients whose disease had progressed following platinum‑based chemotherapy and anti‑PD‑1/L1 treatment. Safety findings were consistent with prior studies. Merck intends to present the results at an upcoming medical forum, consult with regulators worldwide, and use its Commissioner’s National Priority Voucher to speed U.S. FDA review.
This marks the first global phase 3 success from Merck’s TroFouse program for sac‑TMT and the fifth clinical milestone since the Merck‑Kelun alliance began in 2022. The win places Merck more firmly in the antibody‑drug conjugate race now dominated by Gilead’s Trodelvy and AstraZeneca/Daiichi Sankyo’s Datroway. It also lands as Merck prepares for Keytruda’s patent expiry later this decade, a pivotal moment, since the immunotherapy contributed almost half of the company’s $16.3 billion first‑quarter 2026 sales.
Sac‑TMT’s traction could soften that coming revenue gap if Merck converts positive readouts from its 17 ongoing global phase 3 trials into multiple tumor‑type approvals. Should the endometrial data hold up in lung and breast cancer, a question we’ll soon see answered at this month’s American Society of Clinical Oncology meeting, Merck would be one of the few big pharmas with a genuine TROP2 franchise. For investors, attention centers on regulatory timing and how swiftly the company can turn data into commercial pull‑through. For payers, the real issue is the durability and tolerability of ADC therapy in post‑immunotherapy care settings, factors that will shape formulary access and contracting approaches. Personally, I think the next six months will test whether Merck’s bet on ADCs feels like a bold diversification or a late scramble. For more background on evolving ADC pricing trends, see RxInfo.ai.
