AstraZeneca's Imfinzi Shows Promise in Early Bladder Cancer, Matching Pfizer's Candidate

AstraZeneca's Imfinzi (durvalumab) has demonstrated encouraging results in a phase 3 trial for patients with high-risk, non-muscle invasive bladder cancer (NMIBC), potentially positioning it as a strong competitor to Pfizer's investigational drug sasanlimab. The findings, presented at the European Society for Medical Oncology (ESMO) Congress in Berlin and simultaneously published in The Lancet, suggest that Imfinzi could offer a new treatment option for patients with this challenging form of early-stage bladder cancer.

Imfinzi's Performance in the Potomac Trial

In the Potomac trial, Imfinzi, when added to the standard of care (SOC) regimen, showed a 32% reduction in the risk of disease recurrence or death compared to SOC alone. The study, which followed patients for a median of 60.7 months, revealed that an estimated 87% of patients treated with Imfinzi remained alive and disease-free at two years, compared to 82% in the control arm.

Dr. Maria De Santis, a principal investigator in the Potomac trial, emphasized the significance of these results, stating, "While patients with early-stage bladder cancer are treated with the goal of cure, early recurrence is common among those with high-risk non-muscle-invasive bladder cancer. This can lead to repeated surgical procedures and more intensive treatment, including removing a patient's bladder which deeply affects their quality of life."

Comparison with Pfizer's Sasanlimab

Interestingly, the results for Imfinzi appear to be on par with those reported earlier this year for Pfizer's PD-1 inhibitor sasanlimab. In Pfizer's Crest trial, sasanlimab also demonstrated a 32% reduction in the risk of disease recurrence or death when added to SOC. After three years, 82% of patients receiving sasanlimab plus SOC were alive and disease-free, compared to 75% in the control group.

While cross-trial comparisons can be problematic due to differences in study populations and other factors, the similar efficacy results suggest that both Imfinzi and sasanlimab could potentially offer new treatment options for NMIBC patients.

Safety Considerations and Overall Survival

Both trials reported increased adverse events in the immunotherapy arms. In the Potomac trial, grade 3 and 4 adverse events occurred in 34% of patients receiving Imfinzi plus SOC, compared to 17% in the SOC-only group. Similarly, the Pfizer study showed a higher rate of treatment-related adverse events in the sasanlimab arm (17.7%) versus the control arm (1.4%).

Regarding overall survival (OS), neither trial produced statistically significant results. The Potomac trial was not powered to test OS, but AstraZeneca reported no detriment to OS in the Imfinzi arm. In the Pfizer trial, OS was a secondary endpoint, and at a 41-month median follow-up, sasanlimab had not shown superiority to SOC.