Therapeutic Intensification Based on Immune Checkpoint Inhibitors in Non-Muscle Invasive Bladder Cancer: State of the Art and Future Perspectives.

BACKGROUND/

OBJECTIVES

Systemic immunotherapy, previously used mainly for advanced urothelial carcinoma, now plays an important role in the treatment of non-muscle invasive bladder cancer (NMIBC), either alone or combined with intravesical BCG instillations.

METHODS

We conducted a collaborative, comprehensive review to summarize the key evidence and future perspectives on therapeutic intensification strategies involving immune checkpoint inhibitors in NMIBC. A total of 51 references published between 2000 and 2025 were included.

RESULTS

Four phase II studies evaluated pembrolizumab, atezolizumab, durvalumab, and cetrelimab as monotherapy in 28 to 132 BCG-unresponsive NMIBC patients. They reported complete response rates ranging from 12% to 43% after 3 to 12 months of treatment, with a durable response rate ranging from 49% to 57.4% at 12 months. To improve these results, a phase II trial launched this year tests a new systemic combination targeting both the PD-1/PD-L1 axis and the emerging HLA-E/NKG2A pathway. Regarding BCG-naïve high-risk (HR) NMIBC, four phase III studies are evaluating BCG instillations combined with systemic immunotherapy: sasanlimab (CREST), durvalumab (POTOMAC), atezolizumab (ALBAN), and pembrolizumab (KEYNOTE-676), with significant results reported for the CREST and POTOMAC trials. The key challenge remains selecting patients most likely to benefit from this combination therapy while avoiding overtreatment. Identifying predictive biomarkers of tumor aggressiveness and response to immunotherapy also represents a major future challenge.

CONCLUSIONS

Therapeutic intensification using systemic immunotherapy applies to both BCG-unresponsive NMIBC, with a new target pathway (HLA-E/NKG2A), and BCG-naïve HR NMIBC, where the combination of BCG instillations and immunotherapy represents a major breakthrough.