Pembrolizumab (pembro), an immunotherapy, provides durable and clinically meaningful benefits for patients with high-risk nonmuscle-invasive bladder cancer (NMIBC) unresponsive to bacillus Calmette-Guérin (BCG) therapy, investigators concluded in a presentation during the American Society of Clinical Oncology 2020 Virtual Scientific Program.
Use of pembro in these patients also does not appear to limit opportunities for subsequent treatments, include radical cystectomy (RC), according to investigators.
An efficacy analysis that included 96 patients treated with the drug in the KEYNOTE-057 trial showed that 40.6% had a complete response (CR) rate—the study’s primary end point—after a median time of 28.4 months from trial enrollment to data cutoff. The median duration of response (DOR) was 16.2 months, Arjun Vasant Balar, MD, of the Perlmutter Cancer Center at NYU Langone Health in New York, and his colleagues reported in a poster presentation. Among 39 patients who had a CR, 18 (46.2%) had a DOR of 12 months or more. No patient experienced progression to muscle-invasive or metastatic bladder cancer.
Median progression-free survival (PFS) and overall survival (OS) were not reached. At 12 months, PFS and OS were 82.7% and 97.9%, respectively. In addition, 36 patients (37.5%) underwent radical cystectomy (RC) after discontinuing study treatment. The group included 9 (40.9%) of 22 patients who had disease recurrence after an initial CR and 27 (47.4%) of 57 nonresponders.
Of the 36 patients who underwent RC, 33 (91.6%) had no pathologic upstaging to muscle-invasive disease, and 3 (8.3%) had at least pT2 disease at time of RC, Dr Balar’s team reported. With regard to subsequent treatments other than RC, 27 (28.1%) of the 96 patients received additional intravesical therapy (such as BCG, gemcitabine, or mitomycin), 21 (21.9%) underwent local procedures (eg, transurethral resection of bladder tumor), and 3 (3.1%) received systemic therapy (eg, pembrolizumab).
The trial enrolled patients with histologically confirmed high-risk BCG-unresponsive carcinoma in situ (CIS) with or without papillary tumors who received adequate BCG therapy and were ineligible for or opted not to undergo RC. Patients received pembro 200 mg 3 times a week for up to years or until disease recurrence, progression, or unacceptable activity.
For the follow-up analysis, the investigators initially 102 patients treated with pembro. Treatment-related adverse events (TRAEs) occurred in 67 (65.7%) of these patients. The most frequent TRAEs were fatigue, pruritus, and diarrhea (10.8% each). Grade 3 or 4 TRAEs occurred in 13 patients (12.7%), and 21 patients (20.6%) had immune-related AEs. No grade 5 TRAEs occurred.
“With additional follow-up, pembrolizumab continues to show clinically meaningful antitumor activity in patients who have BCG-unresponsive HR NMIBC with CIS (with or without papillary tumors) and who are ineligible for or have elected not to undergo cystectomy,” the authors concluded in a poster presentation.
The Food and Drug Administration on January 8, 2020 approved the drug for BCG-unresponsive high-risk, NMIBC with CIS with or without papillary tumors in patients ineligible for or have opted not to undergo RC. The drug is marketed as KEYTRUDA by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co.
Disclosure: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA provided research funding.
Balar AV, Kamat AM, Kulkarni GS, et al. Pembrolizumab (pembro) for the treatment of patients with Bacillus Calmette-Guérin (BCG) unresponsive, high-risk (HR) non–muscle-invasive bladder cancer (NMIBC): Over two years follow-up of KEYNOTE-057. Presented at the American Society of Clinical Oncology 2020 Virtual Scientific Meeting held May 29 to 31. Abstract 5041. J Clin Oncol. 38: 2020 (suppl; abstr 5041)