AstraZeneca’s Imfinzi has secured EU approval for the treatment of early-stage gastric and gastroesophageal junction (GEJ) cancers, following results from the landmark MATTERHORN trial.
This approval establishes Imfinzi (durvalumab) in combination with FLOT chemotherapy as the first and only perioperative immunotherapy to demonstrate a survival benefit in resectable gastric cancer, offering new hope for patients facing high rates of recurrence.
On March 16, 2026, the European Commission granted marketing authorization for this combination in adults with resectable, early-stage and locally advanced gastric and GEJ cancers. The decision marks a significant shift in curative-intent treatment for a disease where recurrence remains a major challenge despite surgery and chemotherapy.
MATTERHORN Trial Delivers Practice-Changing Survival Data
The EU approval is anchored in compelling overall survival (OS) data from the Phase III MATTERHORN trial, presented at the ESMO Congress 2025. The study demonstrated that Imfinzi combined with FLOT chemotherapy reduced the risk of death by 22% compared to chemotherapy alone (hazard ratio 0.78; 95% CI 0.63-0.96; p=0.021).
Key Survival Outcomes
| Endpoint | Imfinzi + FLOT (n=474) | Chemotherapy Alone (n=474) |
| Median OS | Not reached | Not reached |
| 3-year OS rate | 69% | 62% |
| 2-year OS rate | 76% | 70% |
| Death events | 160 (34%) | 192 (41%) |
| Hazard ratio (95% CI) | 0.78 (0.63-0.96) | — |
An estimated 69% of patients treated with the Imfinzi-based regimen were alive at three years, compared with 62% receiving chemotherapy alone4. The survival benefit was observed regardless of PD-L1 status, with consistent hazard ratios in both PD-L1 positive (TAP ≥1%) and negative (TAP <1%) populations.
You can read more on the MATTERHORN Trial on OncoDaily.
Clinical Significance: Addressing a Critical Unmet Need
Gastric cancer ranks as the fifth most common cancer worldwide and the fifth-leading cause of cancer mortality, with nearly one million new diagnoses and approximately 660,000 deaths reported globally in 20226. Disease recurrence affects approximately one in four patients within one year of surgery, and five-year survival rates remain below 50%.
Dr. Josep Tabernero, MD, PhD, head of the Medical Oncology Department at Vall d’Hebron University Hospital and principal investigator in the MATTERHORN trial, emphasized the transformative nature of the data:
The MATTERHORN data are transformative for patients with early gastric and gastroesophageal cancers, where recurrence is common and long-term prognosis remains poor despite curative-intent surgery and chemotherapy. Nearly seven in 10 patients treated with the durvalumab-based perioperative regimen were alive at three years, and the survival benefit was observed regardless of PD-L1 status. With results like these, this novel treatment should become the new standard of care in this curative-intent setting.
Pathologic Response and Safety Profile
Additional analyses demonstrated that any degree of pathologic response was associated with improved EFS in the Imfinzi arm:
- Pathologic complete response (pCR): HR 0.29; 95% CI 0.08-0.96
- Major pathologic response (MPR): HR 0.32; 95% CI 0.15-0.68
- Any pathologic response: HR 0.60; 95% CI 0.46-0.79
The safety profile for Imfinzi and FLOT was consistent with known profiles of each medicine, and the percentage of patients completing surgery was similar between arms. Grade 3 or higher adverse events were comparable across treatment groups (AstraZeneca 2025).
Executive Perspectives and Strategic Implications
Susan Galbraith, Executive Vice President, Oncology Haematology R&D at AstraZeneca, highlighted the potential treatment paradigm shift:
Imfinzi’s overall survival results, which demonstrate a 22 per cent reduction in the risk of death, could change the treatment paradigm for patients with early gastric and gastroesophageal cancers. This is the first immunotherapy-based perioperative regimen to significantly extend survival in this setting, and these results illustrate our strategy to move novel treatments into early-stage cancers where cure is possible.
The approval expands Imfinzi’s gastrointestinal oncology portfolio, which already includes indications in biliary tract cancer and hepatocellular carcinoma. The drug has now treated more than 414,000 patients across multiple cancer types since its first approval in May 2017.
Market Access and Patient Impact
Approximately 43,000 patients were drug-treated for early-stage and locally advanced gastric or GEJ cancer in the US, EU, and Japan in 2024, with this number expected to reach 62,000 newly diagnosed patients by 2030. The EU approval positions Imfinzi as the standard-of-care option for this patient population, with regulatory reviews ongoing in other jurisdictions.
Key Takeaways
- Imfinzi plus FLOT is the first and only perioperative immunotherapy approved in the EU for early gastric/GEJ cancers
- 22% reduction in death risk and 69% three-year survival rate in MATTERHORN trial
- Survival benefit observed regardless of PD-L1 expression status
- 29% reduction in disease progression, recurrence, or death (EFS endpoint)
- Consistent safety profile with manageable toxicity
- Addresses critical unmet need in disease with high recurrence rates
- Supports AstraZeneca’s strategy to advance immunotherapy into curative-intent settings
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Written by: Semiramida Nina Markosyan, Editor, OncoDaily Canada