Cretostimogene grenadenorepvec delivered complete responses in three-quarters of patients with high-risk, BCG-unresponsive non–muscle-invasive bladder cancer in the phase III BOND-003 Cohort C trial, with most treatment-related adverse events reported as mild and transient. In the international, single-arm study reported in The Lancet Oncology by Tyson et al., 83 of 110 evaluable patients (75%) achieved complete response at any time after a median follow-up of 25.8 months. The result exceeded a prespecified historical benchmark of 20%. Responses appeared to deepen after re-induction, with 14 complete responses occurring post–second induction course, and durability reported at 46% complete response at 12 months and 42% maintaining complete response at 24 months. The therapy is administered intravesically once weekly for six weeks, with options for re-induction and maintenance for responders. The trial’s performance and safety profile add momentum for intravesical oncolytic approaches in a segment with limited effective options.