Pfizer recently announced significant results from its Phase 3 CREST trial evaluating sasanlimab, an investigational subcutaneous PD-1 inhibitor, in combination with BCG (Bacillus Calmette-Guérin) for high-risk, non-muscle invasive bladder cancer (NMIBC)13. The trial demonstrated a 32% reduction in the risk of disease-related events in patients receiving sasanlimab plus BCG induction and maintenance compared to the standard of care23.

The probability of patients remaining event-free at 36 months was 82.1% in the sasanlimab plus BCG group versus 74.8% in the control group receiving only BCG2. This represents the first significant improvement in this therapeutic area in over three decades4.

Despite meeting its primary endpoint of event-free survival (EFS), the study fell short in several secondary objectives2. Most notably, sasanlimab showed no improvement in overall survival (OS)2. Additionally, a third cohort that received sasanlimab with only BCG induction therapy (without maintenance doses) failed to show benefits over standard treatment, indicating that BCG maintenance remains essential even with sasanlimab therapy2.

The treatment was particularly effective in patients with carcinoma in situ (CIS)3. However, researchers observed a higher rate of serious adverse events and immune-mediated adverse events in the sasanlimab treatment arm, though analysts noted that clinicians appeared comfortable with this trade-off given the efficacy benefits in high-risk patients23.

If approved, sasanlimab would become the first PD-1 inhibitor, in combination with BCG, to significantly extend event-free survival in this patient population, potentially changing the treatment landscape for bladder cancer patients4.

Sources:

1. https://www.pfizer.com/news/press-release/press-release-detail/pfizers-sasanlimab-combination-significantly-improves-event

2. https://www.fiercebiotech.com/biotech/pfizer-ties-pd-1-drug-32-bladder-cancer-risk-reduction-phase-3-misses-secondaries

3. https://www.biospace.com/drug-development/pfizers-subcutaneous-pd-1-cuts-risks-in-bladder-cancer-but-misses-os-endpoint

4. https://www.pfizer.com/news/press-release/press-release-detail/pfizers-sasanlimab-combination-bcg-improves-event-free