Imfinzi Secures US Approval as First Immunotherapy Combination for High-Risk NMIBC | iPharmaCenter

AstraZeneca’s Imfinzi (durvalumab) has received approval in the United States as part of the first and only immunotherapy-based combination regimen for adults with previously untreated, high-risk non-muscle-invasive bladder cancer (NMIBC) who have not received Bacillus Calmette-Guérin (BCG).

The approval allows the use of Imfinzi alongside both induction and maintenance BCG therapy in this patient population.

The regulatory decision is supported by findings from the Phase III POTOMAC study. The trial demonstrated that adding Imfinzi to standard BCG induction and maintenance therapy reduced the likelihood of disease recurrence, progression, or death by 32% compared with BCG therapy alone. This benefit was reflected in a disease-free survival hazard ratio of 0.68, with statistical significance achieved.

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After a median follow-up exceeding five years, the combination regimen showed both rapid and durable improvements in disease-free survival, with benefits emerging within four months of treatment initiation. At the time of analysis, the median duration of disease-free survival had not yet been reached in either treatment group.

The safety profile of Imfinzi in combination with BCG remained consistent with previously known data for both therapies, and no unexpected adverse effects were identified during long-term follow-up.

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In addition to these results, AstraZeneca has reported encouraging outcomes from the Phase III VOLGA trial. This study evaluated perioperative use of Imfinzi combined with neoadjuvant enfortumab vedotin in patients with muscle-invasive bladder cancer who were unable or unwilling to receive cisplatin-based chemotherapy. The combination significantly improved event-free survival and overall survival. Another treatment regimen combining Imfinzi, tremelimumab, and enfortumab vedotin also showed meaningful improvement in event-free survival, along with a positive trend in overall survival, although the latter did not reach statistical significance at the interim analysis.

Imfinzi has also been approved in multiple countries for patients with muscle-invasive bladder cancer eligible for cisplatin therapy, based on data from the Phase III NIAGARA trial. Ongoing research continues to explore its role in advanced and metastatic settings, including the Phase III NILE trial.

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Bladder cancer remains one of the most common malignancies worldwide, ranking ninth in overall incidence with more than 614,000 new cases diagnosed annually. The majority of cases are urothelial carcinoma, which originates in the lining of the urinary tract. Approximately 70% of patients are diagnosed at the non-muscle-invasive stage, where the tumor is confined to the inner lining of the bladder.

Each year, more than 31,000 individuals in the United States are treated for high-risk NMIBC. This stage of disease is typically managed with curative intent, beginning with surgical removal of tumors followed by intravesical BCG therapy. Despite treatment, a substantial proportion of patients are classified as high-risk due to tumor characteristics such as stage, grade, and other pathological features. Recurrence remains a major concern, with up to 80% of high-risk patients experiencing disease return within five years.

Patients with high-risk NMIBC often face repeated treatments due to recurrence, including additional chemotherapy cycles and multiple surgical procedures such as transurethral resection of bladder tumors. In many cases, persistent or recurrent disease may ultimately require removal of the bladder. Those who relapse early or become unresponsive to BCG therapy are at particularly high risk of disease progression, highlighting the need for more effective treatment approaches.

The POTOMAC study is a global, randomized, open-label Phase III trial designed to evaluate the efficacy and safety of Imfinzi in combination with BCG in patients with previously untreated high-risk NMIBC who had undergone tumor resection prior to enrollment. A total of 1,018 participants were assigned to one of three groups: Imfinzi with BCG induction and maintenance therapy, Imfinzi with BCG induction alone, or standard BCG induction and maintenance therapy.

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Participants received six weeks of induction BCG treatment, with some groups continuing maintenance therapy for up to two years. The study included patients from over 120 centers across 12 countries spanning North America, Europe, Asia, and Australia. The primary endpoint was disease-free survival, defined as the time from randomization to recurrence of high-risk disease, progression, or death from any cause. Secondary endpoints included overall survival at five years and safety outcomes.

Imfinzi is a monoclonal antibody that targets the PD-L1 protein. By blocking its interaction with PD-1 and CD80, the therapy helps restore immune system activity against cancer cells, counteracting mechanisms tumors use to evade immune detection.