Clinical Summary: 

• Design/Population: In this phase 2 trial, BCG-naive patients with high-grade T1 non-muscle-invasive bladder cancer who declined radical cystectomy received pembrolizumab plus BCG. 
• Key Outcomes: Pembrolizumab plus BCG demonstrated encouraging bladder-preserving activity with limited recurrence and no progression to muscle-invasive disease.
• Clinical Relevance: These findings support pembrolizumab plus BCG as a potential bladder-preserving treatment strategy for selected patients with very high-risk non-muscle-invasive bladder cancer. 

Results from an investigator-initiated phase 2 trial demonstrated that pembrolizumab plus bacillus Calmette–Guérin (BCG) demonstrated encouraging bladder-preserving activity among patients with very high-risk non-muscle-invasive bladder cancer. 

These results were presented by Eugene Pietzak, MD, Memorial Sloan Kettering Cancer Center, New York, New York, at the 2026 American Urological Association (AUA) Annual Meeting in Washington, District of Columbia.

In this single-center trial, researchers enrolled 37 BCG-naïve patients with high-grade T1 disease who had concomitant carcinoma in situ, at least 1 additional adverse-risk feature, and declined radical cystectomy. Patients received 400 mg of pembrolizumab once every 6 weeks for up to 48 weeks plus intravesical BCG induction and maintenance for 1 year. The primary end point was 6-month complete response. Key secondary end points included high-grade recurrence-free survival (RFS) and safety. 

At a median follow-up of 20.8 months, the 6-month complete response rate was 92% with 34 complete responses. No patients progressed to muscle-invasive disease, 4 patients experienced disease recurrence, and 2 patients went on to receive radical cystectomy. The 12-month high-grade RFS rate was 89%, with median RFS not reached. 

Grade ≥3 immune-related adverse events were reported in 21% of patients and were consistent with known immune checkpoint blockade toxicity. One death was reported and deemed possibly related to pembrolizumab. No new safety signals emerged. 

“Although longer follow-up is needed, given historically poor outcomes with BCG alone in this population, our findings support pembrolizumab+BCG as a bladder-preserving option for carefully selected patients with the highest-risk [non-muscle invasive bladder cancer] who decline or are unfit for [radical cystectomy].”

Source: 

Pietzak E, Feld E, Frydenlund N, et al. Intravenous pembrolizumab combined with intravesical Bacillus Calmette-Guerin (BCG) for patients with BCG-naive very high-risk T1 non-muscle invasive bladder cancer traditionally recommended for radical cystectomy. J Urol. Published online: May 1, 2026. doi:10.1097/01.JU.0001192572.07890.f8.11