The safety and efficacy of Atezolizumab (Tecentriq) were studied in a single-arm clinical trial involving 310 patients with locally advanced or metastatic urothelial carcinoma. This trial measured the percentage of patients who experienced complete or partial shrinkage of their tumors (objective response rate). The study also looked at the difference in effect based on “positive” versus “negative” expression of the PD-L1 protein on patients’ tumor-infiltrating immune cells. In all patients, 14.8 percent of participants experienced at least a partial shrinkage of their tumors, an effect that lasted from more than 2.1 to more than 13.8 months at the time of the response analysis. In patients who were classified as “positive” for PD-L1 expression, 26 percent of participants experienced a tumor response (compared to 9.5 percent of participants who were classified as “negative” for PD-L1 expression).
While patients who received Atezolizumab (Tecentriq) experienced a tumor response across the study, the greater effect in those who were classified as “positive” for PD-L1 expression suggests that the level of PD-L1 expression in tumor-infiltrating immune cells may help identify patients who are more likely to respond to treatment with Atezolizumab (Tecentriq). Therefore, today the FDA also approved the Ventana PD-L1 (SP142) assay to detect PD-L1 protein expression levels on patients’ tumor-infiltrating immune cells and help physicians determine which patients may benefit most from treatment with Atezolizumab (Tecentriq).
The most common side effects of treatment with Atezolizumab (Tecentriq) were fatigue, decreased appetite, nausea, urinary tract infection, fever (pyrexia) and constipation. Atezolizumab (Tecentriq) also has the potential to cause infection and serious side effects that result from the immune system effect of Atezolizumab (Tecentriq) (known as “immune-mediated side effects”). These severe immune-mediated side effects involve healthy organs, including the lung, colon and endocrine system.