Kelun-Biotech presented updated Phase 2 results at ESMO on October 24 for sacituzumab tirumotecan, or sac-TMT, combined with Merck’s Keytruda (pembrolizumab) in locally advanced or metastatic urothelial carcinoma. Cohort B enrolled 40 patients who had received no prior systemic therapy and were ineligible for cisplatin, treated with sac-TMT at 4 mg/kg or 5 mg/kg plus pembrolizumab. As of January 26, 2026, at a median follow-up of 22.8 months, the confirmed objective response rate was 68 percent and the confirmed disease control rate was 88 percent, with a median duration of response of 19.4 months.
Responses were observed irrespective of TROP2 and PD-L1 expression, the release said, which matters for a TROP2-directed antibody-drug conjugate: if activity does not depend on target expression, the addressable population is the whole cisplatin-ineligible first-line group rather than a biomarker-selected slice of it. The presentation was a rapid oral report by Professor Xiaojie Bian of Fudan University Shanghai Cancer Center.
Safety was reported in short form in yesterday’s roundup and belongs with the efficacy figures: grade 3 or higher treatment-related adverse events occurred in 63 percent of patients in this combination, a rate that frames how much of the response benefit a Phase 3 control arm will need to justify. Kelun and Merck are running the global Phase 3 TroFuse-055 study on the strength of this cohort.
This is a 40-patient, single-arm Phase 2 cohort, so there is no randomised comparison against the current first-line standards, including the Padcev combinations that produced two of this weekend’s Phase 3 results. Its role is to justify TroFuse-055, and the Phase 3, not this cohort, will decide sac-TMT’s place in bladder cancer.