Safety data show similar Grade 3+ adverse event rates between the Imfinzi+FLOT and FLOT-alone groups (about 71.6% vs. 71.2%), with no impact on surgery completion rates.

Gastric cancer remains a major global burden, with 43,000 anticipated eligible patients in 2025 across the U.S., Europe, and Japan.

Lead investigator Dr. Yelena Y. Janjigian highlighted the regimen as the first immunotherapy approved for neoadjuvant use in gastric/GEJ cancers, noting a three-year survival rate near 70%.

AstraZeneca has reported strong Imfinzi sales and ongoing labeling extensions in other cancers, underscoring a growing commercial footprint.

Matterhorn trial results show Imfinzi added to FLOT improves outcomes, with 69% alive at 3 years versus 62% on FLOT alone and a 22% reduction in death risk, independent of PD-L1 status.

In the phase III MATTERHORN trial, perioperative Imfinzi plus FLOT reduced the risk of progression, recurrence, or death by 29% and showed a 22% reduction in overall mortality (OS HR 0.78; p=0.021) in 948 patients with resectable gastric/GEJ cancers.

This approval marks the third perioperative Imfinzi regimen cleared in the U.S., expanding the survival benefit profile for perioperative immunotherapy.

Taken together, the results position this regimen as a potential new standard of care for curative-intent treatment of early gastric/GEJ cancers by addressing high post-surgical recurrence risk.

The approval is part of AstraZeneca’s broader Perioperative immunotherapy program and aligns with Project Orbis, with regulatory activity ongoing in multiple regions including Australia, Canada, Switzerland, the EU, and Japan.

Imfinzi (durvalumab) has earned FDA approval for perioperative use with the FLOT chemotherapy regimen in adults with resectable stage II, III, or IVA gastric and gastroesophageal junction cancers, administered before and after surgery and as maintenance therapy.

The FDA label supports a perioperative treatment paradigm: Imfinzi with standard FLOT before surgery, followed by post-surgical chemotherapy and then a standalone maintenance phase.

This approval makes Imfinzi the first and only immunotherapy with a perioperative indication for resectable gastric/GEJ cancers.