Merck's Keytruda shows complete response rate of nearly 40% in high-risk NMIBC
Merck announced the first presentation of results from an interim analysis of KEYNOTE-057, a Phase 2 trial evaluating Keytruda, Merck's anti-PD-1 therapy, for previously treated patients with high-risk non-muscle invasive bladder cancer with carcinoma in situ or CIS plus papillary disease. An interim analysis of the study's primary endpoint showed a complete response rate of 38.8 % at three months with Keytruda in patients whose disease was unresponsive to Bacillus Calmette-Guerin therapy, the current standard of care for this disease, and who were ineligible for or who refused to undergo radical cystectomy. The study's primary endpoints are CR rate and disease-free survival rate. The secondary endpoints include safety and duration of response. At the time of analysis, 72.5% of responding patients had an ongoing response and 25% experienced recurrent disease after CR. One patient who did not develop recurrent disease discontinued study treatment and started alternative therapy. No patients in Cohort A developed muscle invasive or metastatic urothelial carcinoma. Of the patients who achieved a CR at three months, 80% had a CR lasting for six months or longer, based on the Kaplan-Meier method. The median duration of response was not yet reached. The median follow-up was 14.0 months. The safety of Keytruda in KEYNOTE-057 was consistent with what has been seen in previous trials among patients treated with Keytruda monotherapy. Treatment-related adverse events occurred in 63.1% of patients. The most common TRAEs with an incidence of 5% or more were pruritus, fatigue, diarrhea, hypothyroidism and maculopapular rash. Grade 3-5 TRAEs occurred in 13 patients, and there was one treatment-related death, per investigator assessment.