Newswise — A recent study by Yale Cancer Center researchers revealed a 41% response to the antibody drug, enfortumab vedotin, by metastatic urothelial (mUC) tumors in a phase I clinical trial. Urothelial cancers include cancers of the bladder, ureters, and renal pelvis. The clinical trial data will be presented at the American Society of Clinical Oncology meeting on Monday, June 5.

The phase I trial sought to determine the safety and tolerability of enfortumab vedotin, which targets the protein Nectin-4, in the treatment of advanced urothelial cancer. Overall, the study found that enfortumab vedotin demonstrated a favorable tolerability profile with encouraging anti-tumor activity in patients previously treated for mUC, including patients where prior immune checkpoint inhibitor therapies had failed.

“The prognosis for patients with metastatic urothelial cancer is grim, so to be able to advance care in any way is huge,” said Daniel P. Petrylak, MD, Professor of Medicine (Medical Oncology) and of Urology at Yale and first author on the study. “I am hopeful that our initial results will lead to further research and eventually improved treatment options for these patients.”

All patients enrolled in the phase I trial received varying dose levels of enfortumab vedotin intravenously (0.5, 0.75, 1, 1.25 mg/kg) once weekly for 3 out of 4 weeks.  81 patients with mUC were treated and of these, 43% had received taxane treatment, and 46% had prior immune checkpoint inhibitor therapy. Anti-tumor activity was observed across the dose range with an overall response of 41%. A complete response was noted in 3 patients at doses ≥1 mg/kg.  Treatment-related adverse events were reported in >10% of patients, and the majority of events were low in severity and included na‎usea, pruritus, and fatigue.

J Clin Oncol 35, 2017 (suppl; abstr 106).