On November 25, 2025, the Food and Drug Administration approved durvalumab (Imfinzi, AstraZeneca) 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).

Full prescribing information for Imfinzi will be posted on Drugs@FDA.

Efficacy and Safety

Efficacy was evaluated in MATTERHORN (NCT04592913), a randomized, double-blind, placebo-controlled, multicenter trial conducted in 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 was not designed to isolate the effect of durvalumab in each phase (neoadjuvant or adjuvant) of treatment. Median EFS was not reached (NR) (95% 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).

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 Dosage

The recommended durvalumab dose 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.

Expedited Programs

This review was conducted under Project Orbis, an initiative of the FDA Oncology Center of Excellence. Project Orbis provides a framework for concurrent submission and review of oncology drugs among international partners. For this review, FDA collaborated with the Australian Therapeutic Goods Administration (TGA), the Brazilian Health Regulatory Agency (ANVISA), Health Canada (HC), Israel’s Ministry of Health (IMoH), and Switzerland’s Swissmedic (SMS). The application reviews are ongoing at the other regulatory agencies.

This review used the Assessment Aid, a voluntary submission from the Applicant to facilitate the FDA’s assessment.

This application was granted priority review. Durvalumab received breakthrough designation and orphan drug designation. FDA expedited programs are described in the Guidance for Industry: Expedited Programs for Serious Conditions-Drugs and Biologics.

Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System or by calling 1-800-FDA-1088.

For assistance with single-patient INDs for investigational oncology products, healthcare professionals may contact OCE’s Project Facilitate at 240-402-0004 or email OncProjectFacilitate@fda.hhs.gov.

Follow the Oncology Center of Excellence on X: @FDAOncology.