AUA 2021: Interim Analysis of Novel Immunotherapy for BCG-Unresponsive Bladder Cancer
Posted: Wednesday, September 22, 2021
Karim Chamie, MD, of UCLA Health Urology in Westwood, Los Angeles, and colleagues conducted the phase II/III QUILT 3.032 study on the addition of N-803—a mutant interleukin-15–based immunostimulatory fusion protein complex—to bacillus Calmette-Guérin (BCG) immunotherapy in patients with non–muscle-invasive bladder cancer. During the 2021 American Urological Association (AUA) Annual Meeting, the investigators revealed that N-803 yielded a complete response rate of 72%, meeting its primary endpoint with a 59% probability of complete responders maintaining complete response for at least 12 months (Abstract PD09-05).
“With the observed strong efficacy and a severe adverse event rate of 1%, N-803 represents a novel treatment option for BCG-unresponsive carcinoma in situ with a favorable benefit:risk ratio, in a therapeutically challenging disease,” the investigators concluded.
A total of 80 patients with high-risk non–muscle-invasive bladder cancer carcinoma in situ were enrolled into cohort A to receive N-803 plus BCG. Participants were previously unresponsive to BCG immunotherapy.
As mentioned, the complete response rate was 72%, with a median duration of complete response of 19.2 months. Low-grade treatment-related adverse events such as hematuria, pollakiuria, dysuria (16%), urgency (14%), and bladder spasm (8%) were among the most common; other adverse events affected less than 6% of individuals.
Treatment-emergent severe adverse events were observed in nine individuals, with a severe adverse event rate of 1% for any event. However, no treatment-emergent severe adverse events were considered to be related to treatment. Additionally, there appeared to be no immune-related severe events. A total of 10 participants proceeded to cystectomy.
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