Investigational Chemotherapy Delivery System Advances Treatment of BCG-Unresponsive Bladder Cancer

By: Celeste L. Dixon
Posted: Monday, May 22, 2023

Partial preliminary results indicating high complete response rates have emerged from SunRISe-1, an ongoing, randomized phase II trial involving TAR-200, a novel intravesical drug delivery system. TAR-200 provides sustained local release of gemcitabine into the bladder of patients who have high-risk non–muscle-invasive bladder cancer, are unresponsive to bacillus Calmette-Guérin (BCG), and are ineligible for or decline radical cystectomy. According to Siamak Daneshmand, MD, of Keck School of Medicine of the University of Southern California, Los Angeles, and colleagues, these findings support further study of this investigational chemotherapy delivery system. These results were presented at the American Urological Association (AUA) Annual Meeting 2023 (Abstract LBA02-03) and published in The Journal of Urology.

Overall complete response rates—the primary endpoint, and centrally confirmed by urine cytology and/or biopsy—were reported for cohort 2 (72.7%; TAR-200 alone) and cohort 3 (38.1%; cetrelimab, an investigational anti–PD-1 agent, alone) In each cohort, 13 patients received treatment and 8 were evaluable. Data were still immature from cohort 1, in which patients received TAR-200 and cetrelimab in combination.

Additionally, the median duration of complete response for cohorts 2 and 3 was not reached after a median follow-up of 13.6 and 12.0 weeks, respectively. “At data cutoff, seven of eight patients in cohort 2 remained [in] complete response, with three ongoing responses ≥ 6 months,” continued the team. The cetrelimab-alone results are consistent with those of other anti–PD-1 treatments in this setting, they noted.

According to the investigators, delivering gemcitabine with TAR-200 limits systemic exposure and reduces toxicity to the bladder, compared with the usual intravesical administration. Of 13 patients in cohort 2 and 13 patients in cohort 3, 11 and 8 patients, respectively, had treatment-emergent adverse events, but most were grade 1 or 2.

In his presentation, Dr. Daneshmand said that TAR-200, with or without cetrelimab, may also be considered for patients with high-risk non–muscle-invasive bladder cancer who are BCG-naive.

Disclosure: No disclosure information was provided.

The Journal of Urology