A good overview on treatment options for non-muscle invasive bladder cancer (NMIBC)  https://www.renalandurologynews.com/bladder-cancer/non-muscle-invasive-bladder-cancer-bcg-unresponsive-management/article/765139/

One other drug that seems to be very effective and was not discussed in the above reference is Vicinium (VB4-845) made by Sesen Bio Inc. currently being evaluated in the Phase 3 VISTA trial. In a Phase 2 clinical trial, Vicinium demonstrated a complete response rate of 40 percent at three months, with no drug-related serious adverse events observed in the trial. In addition to its Phase 3 development for NMIBC, Vicinium is being evaluated in a Phase 1 trial in combination with durvalumab, AstraZeneca’s PD-L1 checkpoint inhibitor, in patients with NMIBC.