Dr. Dreicer on Biomarkers of Response to Immunotherapy in Urothelial Cancer

Robert Dreicer, MD, professor of medicine and urology, University of Virginia Health System, section chief, Medical Oncology, deputy director, UVA Cancer Center, discusses biomarkers of response to immunotherapy in patients with metastatic urothelial cancer.

PD-L1 expression, although an established biomarker in other solid tumors like lung cancer, has not been as helpful in this space. Patients with metastatic urothelial cancer may respond to checkpoint inhibitors even if they are PD-L1—negative, says Dreicer. However, PD-L1 expression may be useful in the frontline setting according to a recent FDA guidance regarding single-agent checkpoint inhibition. Though, the pivotal, phase III frontline studies have yet to report.

A combination of tumor mutational burden and other molecular subtypes of metastatic urothelial cancer may give researchers a better understanding of who will benefit from immunotherapy, Dreicer says. Currently, there are 5 checkpoint inhibitors approved in the second-line setting for patients with metastatic urothelial carcinoma who are refractory to frontline cisplatin. In addition, pembrolizumab (Keytruda) and atezolizumab (Tecentriq) also have indications in the frontline setting for cisplatin-unfit patients.