Imfinzi regimen reduced early disease recurrence among high-risk non-muscle-invasive bladder cancer patients in POTOMAC Phase III trial exploratory analyses

In the first year of treatment, the number of high-risk disease events and Bacillus Calmette-Guérin (BCG)-unresponsive recurrences in the Imfinzi plus BCG arm was almost half the number in the BCG-only arm

Imfinzi plus BCG improved time to cystectomy and cystectomy-free survival, with fewer patients undergoing bladder removal surgery
 

Exploratory analyses of the POTOMAC Phase III trial showed adding one year of treatment with AstraZeneca’s Imfinzi (durvalumab) to BCG induction and maintenance therapy reduced the number of high-risk disease recurrences within the first year, with fewer BCG-unresponsive recurrences in patients with BCG-naïve, high-risk non-muscle-invasive bladder cancer (NMIBC) compared to BCG treatment alone.

These new data were presented today at the 2026 American Urological Association Annual Meeting (AUA) in Washington, DC.

In the first year of treatment, the number of high-risk disease events and BCG-unresponsive recurrences in the Imfinzi plus BCG arm was almost half the number in the BCG-only arm. Across additional analyses, Imfinzi improved the secondary endpoint of time to cystectomy, as well as cystectomy-free survival, with fewer patients in the Imfinzi arm undergoing bladder removal surgery compared to patients treated with BCG alone (see data table below for details).

In subgroups of patients with any papillary tumours (with or without carcinoma in situ [CIS]) or with papillary tumours only (without CIS), the Imfinzi plus BCG regimen reduced the risk of high-risk disease recurrence, progression or death by 39% and 44%, respectively, compared to BCG alone (based on DFS hazard ratios [HR] of 0.61 and 0.56, respectively; 95% confidence interval [CI] 0.43-0.84 and 0.37-0.84 [p=0.0046], respectively).

Neal Shore, MD, FACS, Director of START Carolinas / Head of the Carolina Urologic Research Center and co-principal investigator in the trial, said: “Nearly 40 per cent of patients with high-risk non-muscle-invasive bladder cancer who relapse become unresponsive to BCG therapy and face a higher likelihood of bladder removal surgery. 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 and adding further compelling evidence for the benefit of this regimen for this group of patients.”

Leora Horn, Senior Vice President, Late Development Oncology, Oncology R&D, AstraZeneca, said: “These new analyses reinforce the benefit of Imfinzi plus BCG for patients with high-risk non-muscle-invasive bladder cancer, with data showing that this potential new treatment option reduces recurrences within the first year of treatment and decreases the risk of cystectomy. The results of POTOMAC build on the impact Imfinzi is having in muscle-invasive bladder cancer, further validating our approach to bring novel therapies into earlier-stage settings where they can have the greatest impact on patients’ lives.”

These new data build on findings presented at the European Society for Medical Oncology (ESMO) Congress 2025 and simultaneously published in The Lancet, which showed POTOMAC met the primary endpoint of disease-free survival (DFS). In the intent-to-treat (ITT) population, patients treated with the Imfinzi regimen showed a 32% reduction in the risk of high-risk disease recurrence, progression or death versus the comparator arm (based on a DFS HR of 0.68; 95% CI 0.50-0.93; p=0.0154). Estimated median DFS was not yet reached for either arm. An estimated 87% of patients treated with the Imfinzi regimen remained alive and disease-free at two years compared to 82% in the comparator arm.

Summary of prespecified and post-hoc exploratory analyses (ITT): POTOMAC

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 signals identified, with a median follow-up of more than five years for DFS.

Regulatory submissions based on the POTOMAC data are under review in the US, European Union (EU), Japan and several other countries. 

Yesterday, positive high-level results from the VOLGA Phase III clinical trial were announced, showing that perioperative Imfinzi plus neoadjuvant enfortumab vedotin (EV) demonstrated statistically significant and clinically meaningful improvements in event-free survival (EFS) and overall survival (OS) in patients with MIBC who are not eligible for or had declined cisplatin-based chemotherapy. Imfinzi plus Imjudo (tremelimumab) in combination with neoadjuvant EV demonstrated a statistically significant and clinically meaningful improvement in EFS and a favourable trend for OS; however, the OS data were not statistically significant at this planned interim analysis and will be formally reassessed at a subsequent analysis.

Imfinzi is approved in over 40 countries for patients with cisplatin-eligible MIBC, based on the NIAGARA Phase III trial, and continues to be investigated in locally advanced or metastatic disease in the NILE Phase III trial.  

Data will also be presented at AUA on 16 May from the US-based, open-label, single-arm PATAPSCO Phase IIIb trial, which will provide additional safety data for Imfinzi in patients with BCG-naïve, high-risk NMIBC (abstract #PD09-07). 

Notes

Bladder cancer
Bladder cancer is the 9th most common cancer in the world.¹ More than 70% of 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.^2,3 Most patients with NMIBC have papillary tumour types, with their prognosis depending on disease stage and grade.⁴ About half of patients with NMIBC are classified as high-risk for disease progression or recurrence because of certain characteristics such as their tumour grade, stage and specific tumour features.⁵

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 BCG treatment directly in the bladder.^6,7 Up to 80% of high-risk patients experience disease recurrence within five years of treatment.⁵

Many high-risk patients with recurrent disease undergo additional rounds of chemotherapy and repeated invasive procedures such as TURBT. High-risk patients who experience early recurrence and those who become unresponsive to BCG treatment are at a particularly increased risk of disease progression that may require bladder removal, underscoring the critical need for new treatment options in this curative-intent setting.⁷

POTOMAC
POTOMAC is a randomised, open-label, multi-centre, global Phase III trial evaluating Imfinzi in combination with BCG therapy as a treatment for patients with BCG-naïve, high-risk NMIBC who have undergone TURBT prior to randomisation. In the trial, 1,018 patients were randomised 1:1:1 to receive Imfinzi plus BCG induction and maintenance therapy, or Imfinzi plus BCG induction-only therapy, versus BCG induction and maintenance therapy. In the POTOMAC trial, patients received six weeks of BCG induction therapy with or without two years of BCG maintenance therapy. With median follow-up for DFS exceeding five years, the POTOMAC trial features a notably long observation period among NMIBC trials.

The trial was conducted in more than 120 centres across 12 countries including Canada, Australia 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 (etoposide and either carboplatin or cisplatin) for the treatment of extensive-stage SCLC.

In addition to its indications in lung cancers, Imfinzi is approved in combination with chemotherapy (gemcitabine plus cisplatin) 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 EU. In resectable gastric and gastroesophageal junction cancers, perioperative Imfinzi added to standard-of-care chemotherapy is approved in the US and EU. Additionally, in April 2026, Imfinzi in combination with Imjudo, lenvatinib and transarterial chemoembolisation (TACE) demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of progression-free survival versus TACE alone for patients with unresectable HCC eligible for embolisation in the EMERALD-3 Phase III trial.

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 414,000 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 SCLC, NSCLC, bladder cancer, breast cancer, several gastrointestinal and gynaecologic cancers, and other solid tumours.

AstraZeneca in immuno-oncology (IO)
AstraZeneca is a pioneer in introducing the concept of immunotherapy into dedicated clinical areas of high unmet medical need. The Company has a comprehensive and diverse IO portfolio and pipeline anchored in immunotherapies designed to overcome evasion of the anti-tumour immune response and stimulate the body’s immune system to attack tumours.

AstraZeneca strives to redefine cancer care and help transform outcomes for patients with Imfinzi as a monotherapy and in combination with Imjudo as well as other novel immunotherapies and modalities. The Company is also investigating next-generation immunotherapies like bispecific antibodies and therapeutics that harness different aspects of immunity to target cancer, including cell therapy and T-cell engagers.

AstraZeneca is pursuing an innovative clinical strategy to bring IO-based therapies that deliver long-term survival to new settings across a wide range of cancer types. The Company is focused on exploring novel combination approaches to help prevent treatment resistance and drive longer immune responses. With an extensive clinical programme, the Company also champions the use of IO treatment in earlier disease stages, where there is the greatest potential for cure.

AstraZeneca in oncology
AstraZeneca is leading a revolution in oncology with the ambition to provide cures for cancer in every form, following the science to understand cancer and all its complexities to discover, develop and deliver life-changing medicines to patients.

The Company’s focus is on some of the most challenging cancers. It is through persistent innovation that AstraZeneca has built one of the most diverse portfolios and pipelines in the industry, with the potential to catalyse changes in the practice of medicine and transform the patient experience.

AstraZeneca has the vision to redefine cancer care and, one day, eliminate cancer as a cause of death.

AstraZeneca
AstraZeneca (LSE/STO/NYSE: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Disease, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca’s innovative medicines are sold in more than 125 countries and used by millions of patients worldwide. Please visit astrazeneca.com and follow the Company on Social Media @AstraZeneca.

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References

1. World Health Organization. International Agency for Research on Cancer. Bladder Fact Sheet. Available at: https://gco.iarc.who.int/media/globocan/factsheets/cancers/30-bladder-fact-sheet.pdf. Accessed May 2026.
2. American Cancer Society. What is bladder cancer? Available at: https://www.cancer.org/cancer/bladder-cancer/about/what-is-bladder-cancer.html. Accessed May 2026.
3. Fuge O, et al. Immunotherapy for bladder cancer. Res Rep Urol. 2015;7:65-79.
4. Llano A, et al. Carcinoma in situ (CIS): is there a difference in efficacy between various BCG strains? A comprehensive review of the literature. Cancers (Basel). 2024;16(2):245.
5. Porten SP, et al. High-risk non–muscle-invasive bladder cancer: definition and epidemiology. Curr Opin Urol. 2012;22:385-389.
6. AstraZeneca PLC. Investor relations epidemiology spreadsheet. Available at: https://www.astrazeneca.com/investor-relations.html. Accessed May 2026.
7. Gontero P, et al. EAU Guidelines on Non–muscle-invasive Bladder Cancer (TaT1 and CIS). 2025. Edn. presented at the EAU Annual Congress Madrid 2025. ISBN 978-94-92671-29-5. 

Veeva ID: Z4-83349
Date of preparation: May 2026