Preliminary results from a phase 2 study suggest that tislelizumab combined with radiotherapy may be a potential bladder-preserving therapy for bacillus Calmette-Guérin (BCG)-unresponsible patients with high-risk non-muscle-invasive bladder cancer (NMIBC) who were ineligible for or refused radical cystectomy.

Zhiyong Li, MD, Sun Yat-sen University Cancer Center, Guangzhou, China, presented the results on Friday, February 17, 2023, at the 2023 ASCO Genitourinary Cancers Symposium in San Francisco, CA.

The open-label, single-arm study enrolled 14 patients with high-risk non-muscle-invasive bladder cancer (non-carcinoma in situ, papillary) that was nonresponsive to BGC. All patients underwent transurethral resection of bladder tumor and within the 2 weeks post-surgery received 200 mg tislelizumab on day 1 of each 21-day cycle, for 8 cycles. Patients also received a total radiotherapy dose of 60 to 66 Gray in 30 to 33 fractions over 7 weeks. The primary end point of this study was 12-month disease-free survival (DFS) rate, with secondary end points including bladder-preservation rate, overall survival (OS), and safety.

By September 2022, 10 of the 14 patients had completed therapy and were analyzed. With a median follow-up duration of 20.3 months, the 12-month DFS rate was 80.0%, and the 24-month DFS rate was 60.0%. The 24-month bladder preservation rate was 100%. The 24-month OS rate was also 100%.

Treatment-related adverse events of any grade included rash, neutropenia, hyperthyroidism, aspartate aminotransferase (AST)/alanine transaminase (ALT) increase, and hyperglycemia.

Dr Li and coauthors concluded that tislelizumab combined with radiation is “a promising bladder-preserving therapy” for this patient population.

Source:

Li Z, He L, Li X, et al. Preliminary results from a phase II study of tislelizumab combined with radiotherapy as bladder-preserving treatment for patients with high-risk non-muscle-invasive bladder cancer (HR NMIBC) unresponsive to bacillus Calmettte-Guerin (BCG). Presented at 2023 ASCO Genitourinary Cancers Symposium; February 17-19; San Francisco, CA. Abstract 510