AstraZeneca’s Imfinzi (durvalumab) in combination with standard-of-care FLOT chemotherapy (fluorouracil, leucovorin, oxaliplatin, and docetaxel) has been recommended for approval in the European Union (EU) for the treatment of adult patients with resectable, early-stage and locally advanced (Stages II, III, IVA) gastric and gastroesophageal junction (GEJ) cancers. The regimen includes neoadjuvant Imfinzi in combination with chemotherapy before surgery, followed by adjuvant Imfinzi in combination with chemotherapy, then Imfinzi monotherapy.
The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency based its positive opinion on event-free survival (EFS) and overall survival (OS) data from the MATTERHORN Phase III trial. The EFS results were presented during the Plenary Session at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting and simultaneously published in The New England Journal of Medicine.
In a planned interim analysis, patients treated with the Imfinzi-based perioperative regimen showed a 29% reduction in the risk of disease progression, recurrence or death versus chemotherapy alone (based on an EFS hazard ratio [HR] of 0.71; 95% confidence interval [CI] 0.58–0.86; p<0.001). Estimated median EFS was not yet reached for the Imfinzi arm versus 32.8 months for the comparator arm. An estimated 78.2% of patients treated with the Imfinzi-based perioperative regimen were event-free at one year, compared to 74.0% in the comparator arm; the estimated 24-month EFS rate was 67.4% versus 58.5%, respectively.
In the final OS analysis, results showed the Imfinzi and FLOT perioperative regimen demonstrated a statistically significant and clinically meaningful survival improvement, reducing the risk of death by 22% compared to chemotherapy alone (based on a HR of 0.78; 95% CI 0.63-0.96; p=0.021). An estimated 69% of patients treated with the Imfinzi-based regimen were alive at three years compared with 62% in the comparator arm. At each subsequent prespecified OS landmark, the survival curves indicated increasing separation, signaling a greater magnitude of benefit over time for the Imfinzi-based regimen. An OS benefit was observed regardless of PD-L1 status. OS results from MATTERHORN were presented in a Proffered Paper session at the European Society for Medical Oncology (ESMO) Congress 2025.
Josep Tabernero, MD, PhD, head of the Medical Oncology Department at Vall d'Hebron University Hospital and director of the Vall d’Hebron Institute of Oncology (VHIO) in Barcelona, Spain, and principal investigator in the MATTERHORN trial, said: This recommendation signals a major step forward for patients in the EU with early gastric and gastroesophageal junction cancers, who have historically faced high rates of recurrence and poor long-term outcomes despite curative-intent surgery and chemotherapy. This durvalumab-based perioperative regimen is the first immunotherapy approach to significantly extend survival in this setting, and if approved, should set a new standard of care.”
Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca, said: “Imfinzi plus FLOT demonstrated a durable, increasing long-term survival benefit in the MATTERHORN trial, with more than two-thirds of patients alive at three years. The CHMP recommendation marks further progress toward our goal to offer novel approaches in early-stage cancers where there is the greatest chance for cure and brings us closer to providing the third perioperative Imfinzi-based regimen in the EU.”
Gastric cancer is the fifth leading cause of cancer death globally, with nearly one million people diagnosed each year.1 In 2024, there were roughly 43,000 drug-treated patients in the US, EU and Japan in early-stage and locally advanced gastric or GEJ cancer.2 Approximately 62,000 patients in these regions are expected to be newly diagnosed in this setting by 2030.3
The safety profile for Imfinzi and FLOT chemotherapy was consistent with the known profiles of each medicine, and the percentage of patients that completed surgery was similar compared to chemotherapy alone. Grade 3 or higher adverse events due to any cause were similar between the two arms (71.6% for Imfinzi and FLOT arm; 71.2% for comparator arm).
Imfinzi is approved in the US and other countries in this same indication based on the MATTERHORN results. Regulatory applications are currently under review in Japan and several other countries.
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