The Phase 2 RC48G001 study evaluated disitamab vedotin in patients with advanced urothelial (bladder) cancer. Disitamab vedotin is an antibody-drug conjugate that targets the HER2 protein on cancer cells. After attaching to HER2, it enters the cell and releases a chemotherapy drug (MMAE) that kills the cancer cell from inside.
The study included patients with both high and low levels of HER2 expression. In both groups, more than 50% of patients had significant tumor shrinkage, and over 84% achieved disease control, meaning their cancer shrank or stayed stable. Median overall survival ranged from 17 to 20 months, showing similar benefit regardless of HER2 level.
Side effects were common but mostly mild to moderate, including fatigue, numbness or tingling in the hands and feet, nausea, and loss of appetite. About 60% of patients required dose reductions, mainly due to nerve-related symptoms or fatigue. Based on these encouraging results, a Phase 3 trial is now testing disitamab vedotin combined with pembrolizumab as a first-line treatment.