SunRISe-1: TAR-200, Cetrelimab for BCG-Unresponsive High-Risk NMIBC

Results of the SunRISe-1 study, presented as a late-breaking abstract at the European Society for Medical Oncology Congress 2024, provide support for continued development of TAR-200 monotherapy in patients with Bacillus Calmette-Guérin (BCG)-unresponsive high-risk non-muscle invasive bladder cancer (NMIBC).

Limited treatment options exist for patients with high-risk NMIBC who are unresponsive to BCG. TAR-200 is an intravesical targeted releasing system that provides gemcitabine delivery in the bladder over three weeks.

SunRISe-1 was designed as a randomized, phase 2b evaluation of the efficacy and safety of TAR-200 plus the anti-PD-1 therapy cetrelimab (cohort 1; n=53)), TAR-200 alone (cohort 2; n=85), and cetrelimab alone (cohort 3; n=28) in patients who are ineligible for or refuse radical cystectomy.

Dr. Michiel S. Van der Heijden reported the results of cohorts 1, 2, and 3. All patients had confirmed carcinoma in situ with their last dose of adequate BCG 12 months or less from their carcinoma in situ diagnosis, as well as an Eastern Cooperative Oncology Group performance score of 0-2. TAR-200 was dosed once every three weeks to week 24 and then once every 12 weeks to week 96. Cetrelimab was dosed once every three weeks to week 78.

The primary endpoint was complete response (CR) at any time. Secondary endpoints included duration of response, overall survival, safety, and tolerability.

After a data cut-off date of May 13, 2024, confirmed rates in cohorts 1, 2, and 3 were 68%, 84%, and 46%, respectively. Dr. Van der Heijden and colleagues noted that low discontinuation rates due to treatment-related adverse events (TRAEs) were observed in cohort 2 (6%) and cohort 3 (7%), with even higher rates in cohort 1 (26% related to TAR-200, 23% related to cetrelimab). No treatment-related deaths were reported.

“TAR-200 monotherapy is highly effective, with the highest single-agent CR rate based on published data to date in pts with BCG-unresponsive high-risk NMIBC, durable responses, and low discontinuation rate from TRAEs,” the study authors concluded. “CET alone provided modest CR rate comparable to other anti-PD-(L)1 agents.”

They added that these results support continued research of TAR-200 monotherapy in this patient population.