Findings from a new study led by Yale Cancer Center researchers show enfortumab vedotin is effective in patients with muscle-invasive bladder cancer (MIBC) not eligible for cisplatin chemotherapy. The data is from Cohort H of the Phase 1/b2 EV-103 clinical trial being presented at the 2022 Annual Meeting of the American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium (ASCO GU) on February 18, 2022.

“Our findings showed more than one-third of patients displayed no evidence of cancer when their bladder was removed after receiving enfortumab vedotin prior to surgery,” said Daniel P. Petrylak, MD, Professor of Medicine (Medical Oncology) and Urology and Co-Director of the Cancer Signaling Research Program at Yale Cancer Center, and principal investigator for the study. “The results are significant and so encouraging as survival rates are poor for muscle-invasive bladder cancer.”

MIBC is a type of bladder cancer where the tumor has spread into the muscle of the bladder wall and more likely to spread to other parts of the body. Twenty five percent of bladder cancers are diagnosed as MIBC. Treatment for MIBC typically combines cisplatin-based chemotherapy with surgery.

In this trial, researchers enrolled patients diagnosed with MIBC, ineligible for cisplatin-based chemotherapy, but eligible for surgical treatment. Patients received three cycles of neoadjuvant (prior to surgery) enfortumab vedotin, an antibody drug, on days one and eight of every three-week cycle. Results from the preliminary analysis of 22 patients showed 36.4% had a pathologic complete response, the primary endpoint, displaying no signs of cancer upon microscopic examination of tissue cells removed during surgery. Half of the patients had a pathological downstaging, or reduction in tumor size. All patients underwent surgery, and there were no surgeries delayed due to treatment from enfortumab vedotin.

Petrylak added, “We look forward to phase 3 studies to further evaluate the effectiveness of enfortumab vedotin.”

Funding for this study was provided by Astellas, a multinational pharmaceutical company, and Seagen, an American biotechnology company.