Dr. Grivas on the IMvigor211 Trial in Metastatic Urothelial Carcinoma

Petros Grivas, MD, PhD, director, University of Washington Medicine’s Genitourinary Cancers Program, associate professor, Oncology, University of Washington, Seattle Cancer Care Alliance, discusses the IMvigor211 trial in metastatic urothelial carcinoma.

The IMvigor211 trial with atezolizumab (Tecentriq) versus chemotherapy did not meet its primary endpoint of overall survival (OS) benefit. However, Grivas explains that the primary endpoint was OS in the subset of patients with high PD-L1 expression.

The trial was designed in a hierarchal fashion. Therefore, the primary endpoint of OS had to be met before investigators examined the combination in all-comers. However, Grivas explains that the investigators used a different assay to evaluate PD-L1 expression compared with other trials.

In this study, the assay showed that patients who had a higher PD-L1 expression lived longer and had better outcomes. However, Grivas explains that it is more difficult to see a difference between the 2 arms if people live longer in this subset. That may be why the primary endpoint of the trial was negative.

In all-comers, there was a statistically significant difference with atezolizumab versus chemotherapy in platinum-refractory advanced urothelial cancer. Therefore, if the study was not designed in a hierarchal fashion, the trial would have been positive by statistical criteria, states Grivas.