Imfinzi Plus BCG Reduces Early Recurrence Risk in High-Risk NMIBC, Exploratory POTOMAC Analyses Show

New exploratory analyses from the Phase 3 POTOMAC trial suggest that adding AstraZeneca’s durvalumab (Imfinzi) to Bacillus Calmette-Guérin (BCG) induction and maintenance therapy may improve outcomes for patients with Bacillus Calmette-Guérin-naïve, high-risk non-muscle-invasive bladder cancer (NMIBC). Presented at the 2026 American Urological Association Annual Meeting in Washington, DC, the findings demonstrated reductions in early high-risk disease recurrence and fewer BCG-unresponsive recurrences compared with BCG therapy alone.¹

Investigators reported that during the first year of treatment, the number of high-risk disease events and BCG-unresponsive recurrences in the Imfinzi-plus-BCG arm was nearly half that observed in the BCG-only arm. Additional analyses also showed improvements in time to cystectomy and cystectomy-free survival, suggesting the regimen may help patients preserve bladder function longer while delaying invasive surgery.¹

Exploratory analyses highlight early disease control

The exploratory analyses build on previously reported POTOMAC data presented at the European Society for Medical Oncology Congress 2025 and published in The Lancet, where the study met its primary endpoint of disease-free survival (DFS). In the intent-to-treat population, the Imfinzi regimen reduced the risk of high-risk disease recurrence, progression, or death by 32% compared with BCG alone (hazard ratio, 0.68; 95% CI, 0.50-0.93; P=0.0154).¹

Among patients with papillary tumors, with or without carcinoma in situ, the regimen reduced the risk of recurrence, progression, or death by 39%. In patients with papillary tumors only, the risk reduction reached 44%, underscoring the potential clinical benefit of combining immunotherapy with intravesical BCG in earlier-stage bladder cancer settings.¹

According to the study investigators, 24 patients in the Imfinzi arm experienced high-risk disease events within 12 months compared with 42 patients in the BCG-only group. Median time to a high-risk disease event was also extended from 8.3 months with BCG alone to 14.1 months with the Imfinzi combination.¹

Potential impact on bladder preservation

Bladder preservation remains a central treatment goal in high-risk NMIBC, particularly for patients who relapse after BCG therapy and may otherwise require radical cystectomy. In POTOMAC, fewer patients receiving Imfinzi underwent bladder removal surgery compared with those treated with BCG alone. Investigators reported cystectomy events in 4% of patients receiving the combination regimen versus 6% in the comparator arm.¹

“These new data from POTOMAC show that adding one year of durvalumab to BCG induction and maintenance therapy can reduce early high-risk recurrences and BCG-unresponsive recurrences, extending the time that patients live with their bladder intact,” said Neal Shore, MD, FACS, co-principal investigator of the trial.

The regimen’s safety profile remained consistent with the known profiles of Imfinzi and BCG, with no new safety signals identified after a median follow-up exceeding five years for DFS. Investigators noted that the extended observation period provides important long-term insight into recurrence patterns and bladder preservation outcomes in NMIBC.¹

Clinical context and trial background

NMIBC accounts for more than 70% of newly diagnosed bladder cancer cases, and approximately half of these patients are considered high-risk for recurrence or progression.² Current standard treatment typically involves transurethral resection of the bladder tumor followed by intravesical BCG therapy; however, recurrence rates remain high, with up to 80% of high-risk patients experiencing recurrence within five years.³

POTOMAC is a randomized, open-label, global Phase 3 study evaluating Imfinzi in combination with BCG induction and maintenance therapy in more than 1,000 patients with BCG-naïve, high-risk NMIBC following transurethral resection. Patients were randomized to receive Imfinzi plus BCG maintenance, Imfinzi plus BCG induction only, or BCG induction and maintenance alone.¹

The study reflects a broader shift toward evaluating immunotherapy earlier in the bladder cancer treatment paradigm. Imfinzi is already approved in multiple oncologic indications, including muscle-invasive bladder cancer, and AstraZeneca continues to investigate the agent across earlier-stage and perioperative settings. Regulatory submissions based on the POTOMAC findings are currently under review in the US, EU, Japan, and other regions.¹

References

1. IMFINZI regimen reduced early disease recurrence among high-risk non-muscle-invasive bladder cancer patients in POTOMAC Phase III trial exploratory analyses. (2026 May 15). AstraZeneca.
2. What Is Bladder Cancer? American Cancer Society. Accessed May 2026.
3. Gontero P, et al. (2025). EAU Guidelines on Non–muscle-invasive Bladder Cancer (TaT1 and CIS). European Association of Urology.
4. Porten SP, et al. (2012 Sep). High-risk non–muscle-invasive bladder cancer: definition and epidemiology. Curr Opin Urol. https://pubmed.ncbi.nlm.nih.gov/22842681/