Posted: Tuesday, January 25, 2022
Toripalimab demonstrated durable clinical responses in patients with previously treated locally advanced or metastatic urothelial carcinoma, according to Jun Guo, MD, PhD, of Peking University Cancer Hospital and Institute, Beijing, and colleagues. The results of the multicenter phase II POLARIS-03 trial, which were published in Clinical Cancer Research, also seemed to support a manageable safety profile for this anti–PD‐1 monoclonal antibody.
“To the best of our knowledge, this is the first prospective clinical trial for the second-line treatment of urothelial carcinoma demonstrating a response rate greater than 40% for PD-L1–positive patients receiving an immune checkpoint inhibitor monotherapy,” the investigators commented. “Here we report, also for the first time, the utility of tumor mutational burden in patients with metastatic urothelial carcinoma to predict not only the objective response rate and progression-free survival, but also overall survival benefits in response to an immune checkpoint inhibitor therapy.”
A total of 151 patients were administered second-line treatment with 3 mg/kg of toripalimab once every 2 weeks. Most patients (85%) experienced a treatment-related adverse event. Treatment-related adverse events of grade 3 or higher were observed in 20% of patients.
The objective response rate was 26%, and the disease control rate was 45%. The median durations of response, progression-free survival, and overall survival were 19.7, 2.3, and 14.4 months, respectively. Higher objective response rates were observed in the PD-L1–positive and tumor mutational burden–high groups compared with the PD-L1–negative (42% vs. 17%; P = .002) and tumor mutational burden–low (48% vs. 22%; P = .014) groups. The tumor mutational burden–high group also seemed to experience better progression-free (12.9 vs. 1.8 months; P < .001) and overall (not reached vs. 10 months; P = .018) survival outcomes than those in the tumor mutational burden–low group.
Disclosure: For full disclosures of the study authors, visit clincancerres.aacrjournals.org.