Next-generation drug reduces endometrial cancer progression and death in trial

Endometrial cancer is the most common malignancy of the female reproductive system, and for a long time there has been no standard evidence-based therapy after initial chemotherapy and immunotherapy. The prior landscape can be seen from registry and design documents: TroFuse-005/ENGOT-en23/GOG-3095 is registered as NCT06132958 (MK-2870-005), a Phase 3, randomized, open-label study planned to enroll 710 patients, comparing sacituzumab tirumotecan versus chemotherapy (physician's choice), with co-primary endpoints of BICR-assessed RECIST 1.1 progression-free survival and overall survival, sponsored by Merck Sharp & Dohme, started December 6, 2023, with a primary completion date registered as January 10, 2028 ^[1]; the 2024 design publication confirmed the framework of enrolling patients with histologically confirmed endometrial carcinoma ^[2]. Industry media had reported in May 2026 that the Phase 3 trial met its primary endpoints (according to reports), and this news marks the point of peer-reviewed publication in The Lancet ^[3].

The core of this news is a Phase 3 result published in The Lancet and simultaneously presented at the ESMO annual meeting. The study enrolled patients with advanced or recurrent endometrial cancer previously treated with platinum chemotherapy and immunotherapy (all with pembrolizumab) at more than 200 cancer centers in 29 countries. Per the news release (media-exclusive), the 386 patients randomized to sac-TMT had a 41% lower risk of disease progression than the 390 patients treated with chemotherapy alone, and a 32% lower risk of death; response rates were 35.1% for sac-TMT versus 17.3% for chemotherapy (media-exclusive). On safety, the most frequent adverse events were low blood counts (anemia and neutropenia), oral mucositis/stomatitis, and dry or itchy eyes, all described by researchers as manageable. Three patients in each group died during follow-up, and most patients were monitored for at least a year. The release quotes investigator Bhavana Pothuri as saying these results establish sac-TMT as a new standard treatment in recurrent endometrial cancer and that clinical guidelines will need reassessment, and quotes Michelle Lightfoot that U.S. uterine cancer deaths exceed 14,000 annually with an estimated 68,000 new cases in 2026 alone (media-exclusive), and that Black patients have twice the risk of dying (needs verification).

Relative to prior materials, the advance is this: the registry had the trial ongoing with ACTIVE_NOT_RECRUITING status and a primary completion date of January 10, 2028 ^[1], whereas this announcement provides preliminary efficacy and safety data after at least one year of follow-up, constituting Phase 3 evidence for this drug after immunotherapy in endometrial cancer. The paper states that sac-TMT targets the Trop-2 antigen to deliver a cytotoxic payload to tumor cells; investigators suggest the drug may also have potential in other Trop-2-overexpressing tumors (lung, breast, ovary, intestine), though this remains an investigator outlook rather than validated data. A regulatory distinction: the retrieved approval records for Keytruda QLEX (subcutaneous pembrolizumab) ^[4] do not directly correspond to this product and only indicate continued regulatory expansion of the background immunotherapy agent.

Information not yet disclosed or pending confirmation includes: no regulatory approval action for sac-TMT in this indication so far; the registry primary completion date is January 10, 2028; median PFS/OS values and final overall survival data were not given in the news release; detailed adverse event grades, subsequent regulatory filings, and pricing are undisclosed and await the full publication and regulatory documents. This is an R&D and clinical progress interpretation only and does not constitute investment advice.