Merck cancer drug wins FDA priority review

Unbranded cancer infusion setup in oncology clinic illustrating FDA priority review for new cancer drug MRK

Key Points

01Merck’s sac-TMT cut death risk by 32% in a 776-patient Phase 3 trial
02The drug also reduced risk of progression or death by 41% vs chemotherapy
03FDA accepted a priority review with a June 15, 2027 target action date
04Sac-TMT showed higher tumor response rates with manageable safety profile

Merck’s sac-TMT shows survival benefit, gets priority review

Merck’s investigational cancer therapy sacituzumab tirumotecan (sac-TMT) has extended survival in a pivotal Phase 3 trial in advanced or recurrent endometrial cancer and has been granted priority review by the U.S. Food and Drug Administration. In the 776-patient TroFuse-005 study, sac-TMT reduced the risk of death by 32% compared with physician’s choice chemotherapy, increasing median overall survival to 19.0 months versus 12.1 months. The FDA has accepted a Biologics License Application for sac-TMT and set a Prescription Drug User Fee Act target action date of June 15, 2027, with a regulatory decision expected by June 2027.

Key efficacy results from the TroFuse-005 trial

TroFuse-005 is a randomized, active-controlled, open-label global Phase 3 trial in patients with endometrial carcinoma whose disease returned or progressed after prior platinum-based chemotherapy and anti-PD-1 or anti-PD-L1 immunotherapy. Participants were randomly assigned to sac-TMT or a physician’s choice of doxorubicin or paclitaxel. At a pre-specified interim analysis with a median follow-up of 14.0 months, sac-TMT met its dual primary endpoints of overall survival and progression-free survival, as well as a key secondary endpoint of objective response rate.

Sac-TMT reduced the risk of disease progression or death by 41%, extending median progression-free survival to 7.2 months compared with 3.9 months on chemotherapy. Tumors shrank in 35.1% of patients receiving sac-TMT versus 17.3% of those on chemotherapy, doubling the objective response rate. Complete responses occurred in 6.1% of patients in the sac-TMT arm and 4.5% in the chemotherapy arm, and responses with sac-TMT were durable, with a median duration of response of 11.1 months versus 6.9 months for chemotherapy.

Safety profile and treatment tolerability

No new safety signals were identified in TroFuse-005. Treatment-related adverse events of any grade occurred in 97.1% of patients treated with sac-TMT and 89.6% of those receiving chemotherapy. Grade 3 or higher treatment-related adverse events were reported in 54.4% of patients on sac-TMT and 41.4% on chemotherapy.

The most common Grade 3 or higher clinical events with sac-TMT were anemia in 23.7% of patients, neutropenia in 20.1% and oral mucositis or stomatitis in 9.9%. Treatment discontinuation due to adverse events remained low, at 3.1% in the sac-TMT arm and 4.9% in the chemotherapy arm. Treatment-related adverse events led to death in 0.8% of patients in each arm, and health-related quality of life was maintained over time with sac-TMT.

Regulatory path and clinical context

Based on TroFuse-005 data, Merck is seeking U.S. approval of sac-TMT for adult patients with endometrial cancer who have previously received platinum-containing chemotherapy and a PD-1 or PD-L1 inhibitor, separately or in combination. Sac-TMT is a TROP2-directed antibody-drug conjugate that delivers a cancer-killing payload to cells expressing TROP2, a protein common in endometrial tumors. The late-stage results and priority review position sac-TMT as a potential new treatment option for patients with advanced or recurrent endometrial cancer who have limited alternatives after earlier therapies.

Key Takeaways

01Sac-TMT demonstrated simultaneous gains in overall and progression-free survival, marking a notable advance over standard chemotherapy in this endometrial cancer setting.
02The FDA’s priority review and defined June 15, 2027 action date clarify the regulatory timeline for a potential new therapy in previously treated advanced endometrial cancer.
03Efficacy benefits were accompanied by a higher rate of manageable adverse events, with low discontinuation rates, suggesting a tolerability profile that may support real-world use if approved.

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