AstraZeneca’s Imfinzi is adding yet another landmark perioperative label to its belt with a new FDA approval that gives the drug the title of the first and only immunotherapy marketed to treat early-stage stomach cancer patients both before and after surgery.
With the nod, Imfinzi can be added to standard-of-care FLOT chemotherapy (fluorouracil, leucovorin, oxaliplatin and docetaxel) to treat adult patients with resectable, early-stage and locally advanced gastric and gastroesophageal junction (GEJ) cancers. The approval specifically allows Imfinzi to be used with chemotherapy before surgery, then after surgery with chemotherapy and eventually on its own as a monotherapy.
“This approval ushers in a new clinical paradigm for patients with early gastric and gastroesophageal junction cancers, with Imfinzi plus FLOT delivering a durable survival benefit that increases over time,” Dave Fredrickson, executive vice president and head of AZ's oncology hematology business unit, said in a Tuesday release.
The FDA based its evaluation on AZ’s phase 3 Matterhorn trial, which it presented in June at the 2025 American Society of Clinical Oncology annual meeting. In the study of 948 patients with stages 2 to 4a resectable gastric and GEJ cancers, Imfinzi and FLOT both before and after surgery lowered the risk of disease recurrence, progression or death by 29% compared to FLOT alone.
Imfinzi’s showing in the stomach cancer realm made for the first phase 3 trial of an immunotherapy that demonstrate statistically significant event-free survival improvement in the early-stage setting, AZ said in a March readout.
Matterhorn’s final overall survival analysis, presented at the 2025 European Society for Medical Oncology Congress last month, further confirmed Imfinzi’s perioperative stomach cancer benefits with an estimated 69% of Imfinzi-treated patients remaining alive after three years, compared to 62% in the FLOT-only arm.
To that end, Imfinzi and FLOT proved it could cut the risk of death by 22% compared to chemotherapy alone, AZ reported, with the survival benefit consistent regardless of PD-L1 status.
“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,” principal trial investigator Josep Tabernero, M.D., Ph.D., of the Vall d’Hebron Institute of Oncology, explained in a release announcing the overall survival outcomes in October.
“With results like these, this novel treatment should become the new standard of care in this curative-intent setting,” Tabernero added.
Gastric cancer is the fifth most-common cancer worldwide and the fifth leading cause of cancer mortality, with increasing incidence in younger patients, according to AZ. In 2025, about 43,000 patients in the U.S., Europe and Japan were treated for early-stage gastric or GEJ cancer with therapy, the company said.
Imfinzi is proving itself to be a leading force in the perioperative treatment space, having previously bagged perioperative nods in early-stage resectable non-small cell lung cancer (NSCLC) and, more recently, in muscle-invasive bladder cancer (MIBC).
Last year, the FDA’s Oncologic Drugs Advisory Committee unanimously called for a revamp of perioperative clinical trial designs in NSCLC in response to AZ’s Imfinzi bid and its corresponding trial design, with the experts voting in favor of separate assessments weighing the contributions of each treatment phase.
Even so, with its now-third perioperative nod in the bag, the newest milestone “further validates the perioperative approach and underscores our focus on bringing novel treatments to early-stage cancers where cure is the goal,” Fredrickson added.
AZ is busy elsewhere outside of the perioperative setting, positioning its blockbuster Imfinzi for a bladder cancer label extension with a recent win in high-risk, non-MIBC. The drug pulled $1.6 billion in third-quarter sales (PDF), the company reported.