Results presented by AstraZeneca from its phase 3 trial of Imfinzi in patients with high-risk, non-muscle invasive bladder cancer (NMIBC) suggest the PD-L1 inhibitor measures up to Pfizer’s PD-1 candidate sasanlimab.
While cross-trial comparisons can be problematic—often failing to account for differences in study populations and other factors—it is noteworthy that when added to a standard-of-care (SOC) regimen in their respective trials, both Imfinzi and sasanlimab yielded a 32% reduction in the risk of disease recurrence or death compared to SOC alone.
In the indication, the immunotherapy Bacillus Calmette-Guerin (BCG) for induction and maintenance has been the SOC for decades.
Pfizer released data from its Crest trial of sasanlimab in April. For its part, AZ presented its results from the Potomac trial Friday at the European Society for Medical Oncology Congress in Berlin. They also were published simultaneously in The Lancet.
Patients in the AZ trial were treated for a year, with a median follow-up of 60.7 months. At two years of follow-up, an estimated 87% of the patients treated with Imfinzi remained alive and disease-free compared to 82% of those in the comparator arm.
Meanwhile, in the Pfizer study, after three years, 82% of those on sasanlimab and SOC were alive and disease-free compared to 75% of those in the comparator arm.
As for overall survival (OS), neither trial produced a statistically significant result. While the AZ study was not powered to test OS, there were 41 deaths among the 339 patients (12%) who were on Imfinzi plus SOC compared to 52 deaths among the 340 patients (15%) who were on SOC alone. AZ concluded that there was “no detriment to OS,” in the study.
In the Pfizer trial, OS was a secondary endpoint. At a 41-month median follow-up as of April, sasanlimab had fared no better than SOC.
Another similarity between the trials was a significant difference in safety when comparing the study and comparator arms. In the AZ trial, treatment-related adverse events occurred in 21% of those who took the Imfinzi regimen versus 4% of patients in the SOC group. Meanwhile, in the Pfizer study, the rate of treatment-related adverse events was 29% for those who received sasanlimab compared to a 6% rate for the comparator arm.
The results from both studies are likely to pave the way for FDA approvals. There is a need for more options in bladder cancer, with more than 614,000 cases of the cancer type diagnosed each year. More than 70% of new bladder cancer cases are NMIBC, where a tumor is in the inner lining of the bladder but has not yet encroached on the muscle wall.
Of those, roughly half are classified as high risk for disease progression or recurrence, based on the tumor stage and other characteristics.
“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,” Maria De Santis, M.D., a principal investigator in the Potomac trial, said in a release.
Earlier this year, AstraZeneca took Imfinzi to new heights in muscle-invasive bladder cancer with an FDA approval that made it the first immunotherapy cleared to treat patients both before and after surgery. The nod was supported by a trial that showed Imfinzi plus chemotherapy reduced the risk of disease progression or death by 32% compared to chemotherapy alone.
Imfinzi was originally approved to treat certain patients with advanced bladder cancer in 2017, with subsequent nods in endometrial and lung cancers. It became a blockbuster in its second full year on the market, and sales are still scaling up. In the first half of 2025, it generated $2.7 billion, which was a 20% year-over-year increase.