AstraZeneca has announced positive high-level results from the POTOMAC Phase III trial, demonstrating that one year of treatment with Imfinzi (durvalumab) in combination with standard-of-care BCG induction and maintenance therapy significantly improves disease-free survival (DFS) in patients with high-risk non-muscle-invasive bladder cancer (NMIBC), compared to BCG therapy alone.
Significant Disease-Free Survival Benefit Observed
The trial results showed a statistically significant and clinically meaningful improvement in DFS when Imfinzi was added to the existing standard-of-care BCG regimen. Although the trial was not statistically powered to assess overall survival (OS), a descriptive analysis revealed no evidence of detriment in OS outcomes.
Addressing the Challenges of NMIBC
Bladder cancer affects a large patient population, with over 70% diagnosed at the non-muscle-invasive stage. In these cases, the tumor remains confined to the inner lining of the bladder and has not invaded the muscle wall. However, nearly 50% of NMIBC patients are classified as high-risk for disease progression or recurrence due to tumor characteristics such as grade, stage, and other specific features.
Expert Endorsement: Advancing Treatment Standards
Dr. Maria De Santis is the Head of the Interdisciplinary Uro-Oncology Section at Charité Universitätsmedizin Berlin. She is also a principal investigator in the trial. She expressed strong support for the findings:
“These exciting data show that adding one year of durvalumab to the current standard treatment significantly extends patients’ time. This extension helps prevent high-risk disease recurrence or progression. Doctors treat most patients with curative intent, but 80% experience disease return, and nearly half may undergo life-altering bladder removal surgery. These results highlight the urgent need to enhance treatment strategies.”
AstraZeneca Reinforces Commitment to Early-Stage Cancer Innovation
Cristian Massacesi, Chief Medical Officer and Oncology Chief Development Officer at AstraZeneca, underscored the company’s vision:
“The positive results for Imfinzi in the POTOMAC trial represent a significant advance. This breakthrough could allow more patients with early-stage bladder cancer to benefit from this important immunotherapy. This outcome builds on the NIAGARA data. It validates our strategy to bring novel therapies to early-stage disease, where the potential for long-term benefit is greatest.”
Safety Profile Remains Consistent
The combination of Imfinzi with BCG induction and maintenance therapy showed a safety and tolerability profile consistent with each drug individually. Importantly, the addition of Imfinzi did not interfere with patients’ ability to complete the full BCG treatment regimen. No new safety concerns were identified.
Mixed Results from Second Experimental Arm
As reported by AstraZeneca Press release, the trial’s second experimental arm, which tested Imfinzi with BCG induction-only therapy, did not meet the DFS endpoint when compared to the full BCG induction and maintenance therapy.
Next Steps: Regulatory Submissions and Data Presentation
AstraZeneca will present these findings at an upcoming medical conference and submit the data to global regulatory authorities for evaluation.
Imfinzi’s Expanding Role in Bladder Cancer Treatment
Imfinzi already holds regulatory approval in the US and other countries for patients with muscle-invasive bladder cancer (MIBC) based on outcomes from the NIAGARA Phase III trial. The drug continues to be investigated across various stages of bladder cancer, including:
- In cisplatin-ineligible or -refusing patients with MIBC (VOLGA study)
- In locally advanced or metastatic bladder cancer (NILE study)
- In combination therapies across early- and late-stage disease