According to results from a phase 2 trial, pembrolizumab demonstrated antitumor activity among bacillus Calmette-Guérin (BCG)-unresponsive patients with non-carcinoma in situ, papillary, high-risk non-muscle-invasive bladder.

Andrea Necchi, MD, San Raffaele University, Milan, Italy, presented the results from the KEYNOTE-057 trial on Friday, February 17, 2023, at the 2023 ASCO Genitourinary Cancers Symposium in San Francisco, CA.

The single-arm, multicohort trial enrolled 132 patients with high-risk NMIBC (papillary tumors only) who were unresponsive to BCG to Cohort B. Patients received 200 mg pembrolizumab every 3 weeks for ≤35 cycles, or approximately 2 years. Assessment occurred every 12 weeks with CT urography performed every 24 weeks. The primary end points for cohort B were 12-month disease-free survival (DFS) rate of NMIBC and safety.

There was a median of 9.5 cycles administered to patients, with a median of 10 prior BCG installations. The median follow-up duration was 45.4 months. The 12-month DFS rate of NMIBC was 43.5%, the 12-month DFS rate of any disease was 41.7%. The 12-month overall survival was 96.2% with the median overall survival not reached. Following pembrolizumab, 23.5% of patients underwent radical cystectomy. There were 97 patients with a treatment-related adverse event, 19 of which had a grade 3/4. Discontinuation due to a treatment-related adverse event occurred for 14 patients. There were no treatment-related deaths.

Dr Necchi and coauthors concluded, in this patient population, pembrolizumab “showed notable antitumor activity,” adding that patients in this population “who declined or were ineligible to undergo [radical cystectomy] may also benefit from pembro[lizumab] monotherapy.”

Source:

Necchi A, Roumiguié, Esen AA, et al. Pembrolizumab (pembro) monotherapy for patients (pts) with high-risk non-muscle-invasive bladder cancer (HR NMIBC) unresponsive to bacillus Calmette-Guérin (BCG): Results from cohort B of the phase 2 KEYNOTE-057 trial. Presented at 2023 ASCO Genitourinary Cancers Symposium; February 17-19; San Francisco, CA. Abstract LBA442