FDA Grants Priority Review to Imfinzi for Early Gastric Cancers

A supplemental biologics license application for Imfinzi (durvalumab) has been accepted and granted priority review in the U.S. for patients with resectable, early-stage and locally advanced gastric and gastroesophageal junction cancers, according to a news release from AstraZeneca.

The Food and Drug Administration (FDA) will grant priority review to drug applications that could offer meaningful improvements over existing options by enhancing safety, effectiveness, prevention of serious conditions or patient adherence. The agency’s decision is expected in the fourth quarter of 2025, as per the release.

Additionally, Imfinzi was also recently granted breakthrough therapy designation by the FDA in this setting. This designation helps speed up development and review of medicines that may treat serious conditions and address unmet needs.

“This priority review reinforces the potential for a perioperative approach with Imfinzi to transform care for patients with early gastric and gastroesophageal junction cancers, who frequently face disease recurrence or progression even after curative-intent surgery and perioperative chemotherapy,” Susan Galbraith, executive vice president, Oncology Haematology R&D, AstraZeneca, said in the news release. “This novel treatment is the only immunotherapy-based regimen to show a statistically significant reduction in the risk of progression, recurrence or death in this setting, and if approved, is poised to change the clinical paradigm."

The supplemental biologics license application is supported by findings from the MATTERHORN phase 3 trial, which were presented during the 2025 ASCO Annual Meeting Plenary Session and published in The New England Journal of Medicine.

Patients in the trial who received a perioperative regimen of Imfinzi with chemotherapy experienced a 29% reduction in the risk of disease progression, recurrence or death compared with those treated with chemotherapy alone. At the time of the planned interim analysis, median event-free survival had not yet been reached in the Imfinzi arm, while it was 32.8 months in the chemotherapy-only arm. At one year, an estimated 78.2% of patients receiving the Imfinzi-based regimen were event-free, compared with 74% in the comparator group. At two years, event-free survival rates were estimated at 67.4% versus 58.5%, indicating an increasing benefit over time for the Imfinzi-based approach, as per the release.

A strong trend toward improved overall survival was also observed with the Imfinzi-based regimen. Overall survival continues to be monitored and will be formally assessed at the final analysis.

In the trial, patients received Imfinzi with chemotherapy before surgery (neoadjuvant), followed by Imfinzi with chemotherapy after surgery (adjuvant), then Imfinzi alone. The safety profile for Imfinzi combined with FLOT chemotherapy (fluorouracil, leucovorin, oxaliplatin and docetaxel) was consistent with known side effects for these medicines. Rates of grade 3 or higher side effects and the percentage of patients who completed surgery were similar between both treatment groups.

The MATTERHORN trial is studying whether adding Imfinzi to chemotherapy before and after surgery helps people with resectable stomach or gastroesophageal junction cancer. Patients in the study received treatment before surgery (called neoadjuvant therapy) and continued treatment afterward (adjuvant therapy). Researchers are looking at how long patients live without their cancer coming back or getting worse, how many have no signs of cancer in tissue removed during surgery and overall survival.

Imfinzi is a type of immunotherapy designed to help the immune system recognize and respond to cancer.

Other Indications of Imfinzi

Imfinzi is approved for several types of gastrointestinal (GI) cancer, including in combination with chemotherapy for advanced biliary tract cancer and, with or without Imjudo, for liver cancer that cannot be removed with surgery.

Outside GI cancers, Imfinzi is approved for multiple types of lung cancer, including as a maintenance treatment after chemoradiation for non-small cell lung cancer (NSCLC), before and after surgery for resectable NSCLC, and in combination with chemotherapy for advanced NSCLC and small cell lung cancer.

In bladder cancer, Imfinzi is approved before and after surgery alongside chemotherapy for muscle-invasive disease and is showing promise in non–muscle-invasive cases when combined with Bacillus Calmette-Guérin therapy.

Imfinzi is also approved for advanced or recurrent endometrial cancer: alone with chemotherapy for tumors with certain mutations, and in combination with Lynparza and chemotherapy for others.

Reference

1. “Imfinzi granted Priority Review and Breakthrough Therapy Designation in the US for patients with resectable early-stage gastric and gastroesophageal junction cancers,” AstraZeneca. News Release. July 28.

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