Adding Atezolizumab to Chemotherapy for Muscle-Invasive Bladder Cancer
Posted: Thursday, August 5, 2021
Gemcitabine plus cisplatin in combination with the monoclonal antibody atezolizumab appeared to be safe and effective in patients with muscle-invasive bladder cancer, according to a multicenter, single-arm, phase II trial presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4517). Samuel Aaron Funt, MD, of the Memorial Sloan Kettering Cancer Center, New York, and colleagues explained that additional interrogation of the genomic and host immune factors mediating response and resistance to this neoadjuvant regimen is ongoing.
A total of 39 evaluable patients with cT2–T4a N0 M0 muscle-invasive bladder cancer were administered a single dose of atezolizumab. After 2 weeks, they received gemcitabine plus cisplatin in combination with atezolizumab every 21 days for four cycles prior to undergoing radical cystectomy.
The rate of tumor downstaging, defined as a pathologic stage lower than T2 N0, was 69%, and the T0 N0 rate was 38%. At a median follow-up of 16.7 months, the median duration of recurrence-free survival was not reached. The median duration of time from the last dose of chemotherapy to radical cystectomy was 7.8 weeks. Neutropenia (36%), lymphopenia (16%), and anemia (11%) were among the most frequently reported grade 3 to 4 chemotherapy-related adverse events. The investigators reported four possible grade 3 to 4 immune-related adverse events: two cases of asymptomatic grade 3 pancreatic enzyme elevation, one case of grade 3 pancreatitis, and one case of hepatitis requiring steroids.
A total of 10% of patients had PD-L1–positive tumors; this rate was low compared with other studies. All four patients with PD-L1–positive tumors achieved a pathologic stage lower than T2 N0. Compared with patients who responded to treatment, more nonresponders had PD-L1–negative tumors (100% vs. 85%); however, this relationship did not seem to be statistically significant (P = 0.3).
Disclosure: For full disclosures of the study authors, visit coi.asco.org.