The US Food and Drug Administration (FDA) granted accelerated approval to atezolizumab (Tecentriq) for the treatment of locally advanced or metastatic urothelial carcinoma—the most common type of bladder cancer. Atezolizumab is a humanized engineered monoclonal antibody that targets the programmed cell death ligand 1 (PD-L1), which is overexpressed on many tumor types and on various tumor-infiltrating immune cells.
The approval is intended for patients who have disease progression during or following platinum-based chemotherapy, or whose disease has worsened within 12 months of receiving platinum-based neoadjuvant or adjuvant chemotherapy.
“Tecentriq provides these patients with a new therapy targeting the PD-L1 pathway,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, in a press release. “Products that block PD-1/PD-L1 interactions are part of an evolving story about the relationship between the body’s immune system and its interaction with cancer cells.”
Atezolizumab is the first PD-L1 inhibitor approved by the FDA. Other antibodies in this class include two approved anti-PD-1 agents: nivolumab, approved for melanoma, lung cancer, kidney cancer, and classical Hodgkin lymphoma, and pembrolizumab, which is approved for melanoma and lung cancer.
The accelerated approval of atezolizumab was based on the single-arm, phase II IMvigor 210 trial, which included 310 patients with locally advanced or metastatic urothelial carcinoma. A total of 14.8% of patients had partial or complete response that lasted from 2.1 months to 13.8 months at the time of analysis. Patients who were categorized as PD-L1–positive had a 26% response rate compared with 9.5% in patients who were PD-L1–negative.
The FDA has also approved a complementary diagnostic, an assay that detects PD-L1 protein expression levels on patients’ tumor-infiltrating immune cells, to help physicians determine which patients are most likely to respond to treatment with atezolizumab.
The most common side effects seen in the IMvigor 210 trial were fatigue, decreased appetite, nausea, urinary tract infection, pyrexia, and constipation. Atezolizumab can also cause infection and serious immune-mediated side effects that could affect healthy organs such as the lung, endocrine system, and colon.