On May 8, 2025 Astrazeneca reported positive high-level results from the POTOMAC Phase III trial showed one year of treatment with Imfinzi (durvalumab) plus standard-of-care BCG induction and maintenance therapy demonstrated a statistically significant and clinically meaningful improvement in disease-free survival (DFS) for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) compared to BCG induction and maintenance therapy alone (Press release, AstraZeneca, MAY 8, 2025, View Source [SID1234652777]).​

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The trial was not statistically powered to formally test overall survival (OS) however a descriptive analysis demonstrated no detriment.

More than 70% of bladder cancer patients are diagnosed with NMIBC, an early-stage cancer where the tumour is in the tissue that lines the inner surface of the bladder but has not invaded the muscle wall.1-2 About half of patients with NMIBC are classified as high-risk for disease progression or recurrence because of certain characteristics of their cancer, such as tumour grade, stage and specific tumour features.3

Maria De Santis, MD, Head of the Interdisciplinary Uro-Oncology Section at Charité Universitätsmedizin Berlin, Germany, and a principal investigator in the POTOMAC trial, said: "These exciting data show that adding one year of durvalumab to the current standard treatment significantly extends the time patients live without high-risk disease recurrence or progression. While most patients with non-muscle invasive bladder cancer are treated with curative intent, 80 per cent see their disease return and almost half may require life-altering surgery to remove the bladder, underscoring the urgent need to improve treatment."

Cristian Massacesi, Chief Medical Officer and Oncology Chief Development Officer, AstraZeneca, said: "The positive results for Imfinzi in the POTOMAC trial represent a significant advance that will potentially allow more patients with early-stage bladder cancer to benefit from this important immunotherapy. Building on the NIAGARA data, this outcome demonstrates our strategy of bringing novel therapies to patients with early-stage disease where there is the greatest potential for long-term benefit."

The safety and tolerability of Imfinzi plus BCG induction and maintenance therapy was consistent with the known safety profiles of the individual medicines, with no new safety concerns identified. The addition of Imfinzi did not compromise patients’ ability to complete BCG induction and maintenance therapy.

The second experimental arm evaluating Imfinzi plus BCG induction-only therapy compared to BCG induction and maintenance therapy alone did not meet the endpoint of DFS.

These data will be presented at a forthcoming medical meeting and shared with global regulatory authorities.

Imfinzi is approved in the US and other countries for patients with muscle-invasive bladder cancer (MIBC) based on results from the NIAGARA Phase III trial and continues to be investigated across early and late-stage bladder cancer in various treatment combinations, including in patients with MIBC who are ineligible or refuse to take cisplatin (VOLGA) and in locally advanced or metastatic disease (NILE).

Notes

Bladder cancer
Bladder cancer is the 9th most common cancer in the world, with more than 614,000 cases diagnosed each year.4 The most common type is urothelial carcinoma, which begins in the urothelial cells of the urinary tract.2

In 2024, an estimated 125,000 patients were treated for high-risk NMIBC, for which the current standard of care is transurethral resection of bladder tumour (TURBT) followed by administration of BCG directly into the bladder.5-6 Up to 80% of patients experience disease recurrence within five years, and rates of progression in high-risk patients can be as high as 45%.2 There is a critical need for treatment options in this curative-intent setting.

POTOMAC
POTOMAC is a randomised, open-label, multi-centre, global Phase III trial evaluating Imfinzi in combination with BCG therapy as a treatment for 1,018 patients with high-risk, BCG-naïve NMIBC who have undergone TURBT prior to randomisation. Patients were randomised 1:1:1 to receive Imfinzi plus BCG induction and maintenance therapy, or Imfinzi plus BCG induction-only therapy, versus standard-of-care BCG induction and maintenance therapy.

The trial was conducted in more than 120 centres across 12 countries including Canada and others across Europe and Asia. The primary endpoint was DFS, defined as time from randomisation to date of first recurrence of high-risk disease or death from any cause, for Imfinzi plus BCG induction and maintenance therapy compared to BCG induction and maintenance therapy alone. Secondary endpoints included DFS for Imfinzi plus BCG induction only therapy versus the comparator arm, as well as OS at five years and safety across both experimental arms of the trial.

Imfinzi
Imfinzi (durvalumab) is a human monoclonal antibody that binds to the PD-L1 protein and blocks the interaction of PD-L1 with the PD-1 and CD80 proteins, countering the tumour’s immune-evading tactics and releasing the inhibition of immune responses.

In addition to its indication in MIBC, Imfinzi is the global standard of care based on OS in the curative-intent setting of unresectable, Stage III non-small cell lung cancer (NSCLC) in patients whose disease has not progressed after chemoradiotherapy (CRT). Additionally, Imfinzi is approved as a perioperative treatment in combination with neoadjuvant chemotherapy in resectable NSCLC, and in combination with a short course of Imjudo (tremelimumab) and chemotherapy for the treatment of metastatic NSCLC. Imfinzi is also approved for limited-stage small cell lung cancer (SCLC) in patients whose disease has not progressed following concurrent platinum-based CRT; and in combination with chemotherapy for the treatment of extensive-stage SCLC.

Imfinzi is also approved in combination with chemotherapy in locally advanced or metastatic biliary tract cancer and in combination with Imjudo in unresectable hepatocellular carcinoma (HCC). Imfinzi is also approved as a monotherapy in unresectable HCC in Japan and the European Union (EU).

In March 2025, perioperative Imfinzi added to standard-of-care chemotherapy met the primary endpoint of event-free survival in the MATTERHORN Phase III trial in resectable gastric and gastroesophageal junction cancers.

Imfinzi in combination with chemotherapy followed by Imfinzi monotherapy is approved as a 1st-line treatment for primary advanced or recurrent endometrial cancer (mismatch repair deficient disease only in US and EU). Imfinzi in combination with chemotherapy followed by Lynparza (olaparib) and Imfinzi is approved for patients with mismatch repair proficient advanced or recurrent endometrial cancer in EU and Japan.

Since the first approval in May 2017, more than 374,000 patients have been treated with Imfinzi. As part of a broad development programme, Imfinzi is being tested as a single treatment and in combinations with other anti-cancer treatments for patients with NSCLC, bladder cancer, breast cancer, ovarian cancer and several gastrointestinal cancers.