In a phase II study reported in the Journal of Clinical Oncology, Hoosier Cancer Research Network (HCRN) investigators report that switch maintenance pembrolizumab leads to additional objective responses and significantly prolongs progression-free survival in patients with metastatic urothelial cancer achieving at least stable disease with first-line platinum-based chemotherapy.

The multi-center investigator-initiated study, “A Randomized, Double-Blinded, Phase II Study of Maintenance Pembrolizumab versus Placebo after First-line Chemotherapy in Patients with Metastatic Urothelial Cancer: HCRN GU14-182,” was led by the Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, and included 30 member sites of HCRN.

“This is the first study of an immune checkpoint inhibitor to demonstrate a significant delay in progression in advanced bladder cancer when immunotherapy is administered immediately after finishing chemotherapy,” said Matthew Galsky, MD (pictured), sponsor-investigator of the study and a medical oncologist at the Icahn School of Medicine at Mount Sinai. “We are trying to better understand which patients benefit most from this approach using samples collected and have designed follow-up studies to determine if there are combination regimens that might further improve outcomes in the maintenance setting after initial chemotherapy.”

The study enrolled 108 patients, who were randomly assigned to receive pembrolizumab (55 patients) or placebo (53 patients). Objective response rate was 23% with pembrolizumab and 10% with placebo; progression-free survival was 5.4 months with pembrolizumab and 3.0 months with placebo; and median overall survival was 22 months with pembrolizumab and 18.7 months with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% of patients receiving pembrolizumab and 38% receiving placebo.

“This large, multi-center study was designed before the first PD-1 and PD-L1 antibody was approved by the FDA for the treatment of bladder cancer,” Dr. Galsky said. “It was a leap of faith for our investigator colleagues, as no therapies to date had demonstrated an improvement in patient outcomes in this setting. This trial would not have been possible without the strong collaboration of HCRN and HCRN member sites.”

See publication: DOI: 10.1200/JCO.19.03091 Journal of Clinical Oncology.

About Hoosier Cancer Research Network:

Hoosier Cancer Research Network (formerly known as Hoosier Oncology Group) conducts innovative cancer research in collaboration with academic and community physicians and scientists across the United States. The organization provides comprehensive clinical trial management and support, from conception through publication. Created in 1984 as a program of the Walther Cancer Institute, Hoosier Cancer Research Network became an independent nonprofit clinical research organization in 2007. Since its founding, Hoosier Cancer Research Network has conducted more than 210 trials in a variety of cancer types and supportive care, resulting in more than 350 publications. More than 8,500 subjects have participated in Hoosier Cancer Research Network clinical trials.