Pembrolizumab shows encouraging antitumor activity in patients with high-risk nonmuscle-invasive bladder cancer (NMIBC) that is unresponsive to bacillus Calmette-Guérin (BCG) therapy, new data presented at the 2019 Genitourinary Cancers Symposium suggest.
Arjun Vasant Balar, MD, of the Perlmutter Cancer Center at New York University Langone Health, New York, and colleagues studied 102 patients who participated in the single-arm phase 2 KEYNOTE 057 trial. They received treatment with pembrolizumab, a PD-1 inhibitor, for histologically confirmed, high-risk, BCG-unresponsive carcinoma in situ (CIS) with or without papillary disease. Patients were a median age of 73 years. They received a median of 12 prior BCG instillations. The primary study outcome was complete response (CR).
Dr Balar’s team observed a 3-month CR rate (CRR) of 40.2% (95% CI, 30.8%–50.4%). The median follow-up time for the patients in CR was 16.7 months (range 5.9–28.2 months). The median duration of CR was 12.7 months, with 75% of patients having a CR duration of 6 months or more and 53% having a duration of 9 months or more, Dr Balar reported in an oral presentation. Twenty-four complete responders (58.5%) had an ongoing response at the time of data cut-off.
Among the patients with CR, 15 (36.6%) experienced recurrent NMIBC after CR. No patient had progressed to muscle-invasive or metastatic disease.
Treatment-related adverse events (AEs) occurred in 66 patients (64.7%). The most frequent of these AEs were pruritus (10.8%), diarrhea (10.8%), fatigue (9.8%), hypothyroidism (6.9%), and maculopapular rash (5.9%). Grade 3/4 treatment-related AEs occurred in 13 patients (12.7%). Eight patients (7.8%) discontinued treatment because of treatment-related AEs.
Balar AV, Kulkarni GS, Uchio EM, et al. Keynote 057: Phase II trial of Pembrolizumab (pembro) for patients (pts) with high-risk (HR) nonmuscle invasive bladder cancer (NMIBC) unresponsive to bacillus Calmette-Guérin (BCG). Data presented at: the 2019 Genitourinary Cancers Symposium; San Francisco, CA; February 14–16, 2019. Abstract 350.