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Merck (NYSE:MRK) announced detailed results from the Phase 3 AMBASSADOR trial on Friday, noting that its anti-PD1 therapy Keytruda reduced the risk of disease recurrence or death by 31% after surgery in patients with urothelial carcinoma, a form of cancer of the bladder.
At a median follow-up of 22.3 months, the 702-patient study indicated a statistically significant and clinically meaningful improvement for Keytruda in disease-free survival (DFS), one of its two primary endpoints.
However, the study has yet to show statistically significant data for the other dual primary endpoint of overall survival (OS). When median follow-up reached 36.9 months, median OS for Keytruda was 50.9 months, compared with 55.8 months for the no-drug arm.
Regarding tolerability, no new safety concerns emerged, while approximately 48% of patients receiving Keytruda developed grade ≥ 3 adverse events compared to approximately 32% in the observation arm.
The AMBASSADOR study was conducted by Merck (MRK) in collaboration with Pfizer’s (PFE) Seagen unit and Japanese pharmaceutical company Astellas (OTCPK:ALPMF) (OTCPK:ALPMY).
It was designed to evaluate Keytruda as adjuvant therapy for localized muscle-invasive urothelial carcinoma and locally advanced resectable urothelial carcinoma.