FDA
FDA greenlights perioperative Imfinzi for resectable gastric/GEJ adenocarcinoma
On November 25, 2025, FDA approved Imfinzi (durvalumab) with fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) chemotherapy as neoadjuvant and adjuvant treatment, followed by single agent durvalumab, for adults with resectable gastric or gastroesophageal junction adenocarcinoma (GC/GEJC).
Efficacy
Efficacy was evaluated in the randomized, double-blind, placebo-controlled, multicenter MATTERHORN trial (NCT04592913) involving 948 patients with previously untreated and resectable, Stage II to Stage IVA, GC/GEJC. Patients were randomized (1:1) to receive either durvalumab and FLOT or placebo and FLOT.
The major efficacy outcome measure was event-free survival (EFS) by blinded independent central review assessment. Additional efficacy outcome measures were overall survival (OS) and pathological complete response (pCR) rate by blinded central pathology review. The trial wasn’t designed to isolate the effect of durvalumab in each phase (neoadjuvant or adjuvant) of treatment. Median EFS wasn’t reached (NR) (95% confidence interval [CI], 40.7, not estimable [NE]) in the durvalumab + FLOT arm and was 32.8 months (95% CI, 27.9, NE) in the placebo + FLOT arm (hazard ratio [HR], 0.71; 95% CI, 0.58, 0.86; p-value <0.001). Median OS was NR in both arms (HR, 0.78; 95% CI, 0.63, 0.96; p-value 0.021). The pCR rate was 19.2% (95% CI, 15.7, 23.0) and 7.2% (95% CI, 5.0, 9.9) in the respective arms (p-value <0.001).
Safety
The prescribing information includes warnings and precautions for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation, and embryo-fetal toxicity.
Recommended dose
The recommended dosage for patients with a body weight of ≥30 kg is 1,500 mg every 4 weeks with chemotherapy for up to 4 cycles (neoadjuvant and adjuvant treatment), followed by 1,500 mg as a single agent every 4 weeks for up to 10 cycles (adjuvant treatment).
The recommended durvalumab dose for patients with a body weight <30 kg is 20 mg/kg with chemotherapy every 4 weeks for up to 4 cycles (neoadjuvant and adjuvant treatment) and 20 mg/kg as a single agent every 4 weeks for up to 10 cycles (adjuvant treatment).
Treatment should continue until disease progression, recurrence, or unacceptable toxicity, or a maximum of 12 cycles after surgery.
Sources:
FDA approves durvalumab for resectable gastric or gastroesophageal junction adenocarcinoma. [News release]. 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-durvalumab-resectable-gastric-or-gastroesophageal-junction-adenocarcinoma
Imfinzi approved in the US as first and only perioperative immunotherapy for patients with early gastric and gastroesophageal cancers. [News release]. 2025. https://www.astrazeneca.com/media-centre/press-releases/2025/imfinzi-approved-in-the-us-as-first-and-only-perioperative-immunotherapy-for-patients-with-early-gastric-and-gastroesophageal-cancers.html