TAR-200, an intravesical gemcitabine-releasing system, is showing promise in treating non-muscle-invasive bladder cancer (NMIBC) unresponsive to Bacillus Calmette-Guérin (BCG) therapy. Data from the ongoing SunRISe-1 trial, presented at the Society of Urologic Oncology 25th Annual Meeting in Dallas, Texas, indicate encouraging efficacy and a favorable safety profile. Siamak Daneshmand, MD, a professor of urology and director of clinical research at the Keck School of Medicine of the University of Southern California, Los Angeles, discussed the latest findings.
Efficacy and Duration of Response
Initial results from the SunRISe-1 trial are demonstrating high complete response (CR) rates with TAR-200. "Every time we've looked at this, the CR rates, if anything, have gone up. You see it in the 70s. Now we're seeing 85% complete response rates," Dr. Daneshmand noted. These increasing CR rates suggest sustained efficacy over time, which is a critical factor in managing NMIBC.
Safety and Tolerability
The safety and tolerability of TAR-200 are also notable. The SunRISe-1 trial meticulously annotated adverse events (AEs), revealing that the device is generally well-tolerated. Among 85 patients, only 5 discontinued therapy due to side effects. Most AEs were grade 1 or 2, including frequency, urgency, and urinary tract infections (UTIs), which are commonly associated with intravesical therapies. Grade 3 AEs were reported in only 9% of patients and included infections, UTIs, and urinary retention.
Patient Experience and Psychological Impact
Beyond the clinical data, Dr. Daneshmand highlighted the psychological aspect of using a drug-releasing system like TAR-200. Patients may feel reassured by the continuous presence of the device, perceiving that the drug is constantly working in their body. "I've always talked about the psychological aspect of having a drug releasing system in the body that's unmeasured as of yet, where patients, I think, feel that there's something that's working all the time in their body," he explained. This contrasts with single-infusion therapies, potentially offering a psychological benefit.
Trial Design and Future Directions
The SunRISe-1 trial initially included three cohorts: cetrelimab (a PD-1 inhibitor) alone, TAR-200 alone, and TAR-200 plus cetrelimab. A fourth cohort was later added for patients with papillary disease only. The primary objective was to assess the efficacy, safety, and tolerability of TAR-200 in patients with BCG-unresponsive NMIBC, with a focus on the TAR-200 monotherapy arm. Data from the cetrelimab alone arm showed a complete response rate of approximately 37%, consistent with previous findings for PD-1 inhibitors in this setting.
Looking ahead, Dr. Daneshmand suggests exploring combination therapies and instilling other drugs into the device. Future studies could also investigate patient perceptions of TAR-200 compared to other therapies to quantify any differences in psychological impact. The ongoing SunRISe-1 trial and future research endeavors aim to further refine the role of TAR-200 in the treatment landscape for NMIBC.
