Pfizer's Sasanlimab Shows Promise in High-Risk Bladder Cancer, But Misses Overall Survival Endpoint

Pfizer's investigational anti-PD-1 antibody, sasanlimab, has demonstrated significant efficacy in reducing disease events for patients with high-risk non-muscle-invasive bladder cancer (NMIBC), according to results from the Phase III CREST trial presented at the 2025 annual meeting of the American Urological Association.

Sasanlimab Efficacy and Patient Outcomes

The CREST trial, which combined sasanlimab with the standard of care Bacillus Calmette-Guérin (BCG), showed a 32% reduction in the risk of disease recurrence, progression, death due to any cause, or persistence of cancer cells compared to BCG alone. This effect was even more pronounced in patients with early-stage or carcinoma in situ (CIS) disease, who experienced risk reductions of 37% and 47%, respectively.

Patients treated with sasanlimab demonstrated an 82.1% probability of being event-free at 36 months, a marked improvement over those receiving BCG monotherapy. The primary outcome measure of the study was event-free survival (EFS).

Overall Survival and Safety Profile

Despite the positive EFS results, an early interim analysis for overall survival (OS) did not show a significant advantage for the sasanlimab regimen over the BCG control at a median follow-up of 40.9 months. The CREST trial will continue to monitor patients for OS until the final analysis is complete.

The safety profile of sasanlimab was reported to be "generally consistent" with previous studies and the known safety profile of PD-1 inhibitors. Common immune-mediated adverse events included rashes, hepatitis, and pancreatitis. Guggenheim analysts noted a slight increase in immune-mediated adverse events but suggested that physicians appeared comfortable with the added toxicity given the improved efficacy in this high-risk patient group.

Regulatory Outlook and Market Potential

Pfizer has announced plans to share the CREST trial data with global health authorities, aiming to secure approval for sasanlimab. While no specific timeline for submission has been provided, the company's move signals confidence in the drug's potential.

Guggenheim analysts have highlighted the "potential opportunity for sasanlimab in high-risk NMIBC," noting that its efficacy profile was "particularly compelling" in patients with CIS. This development could potentially allow Pfizer to establish a significant presence in the treatment landscape for high-risk non-muscle-invasive bladder cancer.