Durvalumab has been approved by the FDA for the treatment of resectable gastric and gastroesophageal junction adenocarcinoma — meaning stomach cancers that are localized and can be removed surgically.
This approval was granted on 25 November 2025.
It is approved for use with fluorouracil, leucovorin, oxaliplatin, and docetaxel (the FLOT regimen) as both:
Neoadjuvant therapy (before surgery)
Adjuvant therapy (after surgery)
It is also approved for single-agent use after completion of FLOT, as part of the adjuvant phase.
Clinical Trial Details
Trial Name: MATTERHORN
A randomized, double-blind, placebo-controlled Phase 3 clinical study.
Conducted in 948 patients with previously untreated, resectable Stage II to Stage IVA gastric or GEJ adenocarcinoma
Randomization
One group received durvalumab + FLOT
The control group received placebo + FLOT
Efficacy Outcomes Measured
- Event-Free Survival (EFS)
This means time without cancer coming back, progressing, or causing death - Overall Survival (OS)
This measures how long patients lived. OS was not reached, meaning more than half were alive at the time of analysis. - Pathological Complete Response (pCR)
The tumor was completely gone in surgical samples.
The trial did not try to separate the effect of durvalumab as a neoadjuvant vs adjuvant therapy. It evaluated the entire perioperative regimen as one combined strategy.
Why It Was FDA Approved
The durvalumab + FLOT combination showed:
- Longer event-free survival
Patients went longer without progression or recurrence. - Lower risk of death
A 22% reduction in risk vs the placebo group. - Much higher pathological complete response rate
Nearly 3× more patients had complete tumor clearance before surgery.
Warnings Noted in FDA Prescribing Information
- Immune-mediated adverse reactions
- Infusion-related reactions
- Complications in allogeneic stem cell transplant recipients
- Embryo–fetal toxicity
Why does this approval matter?
Because surgery alone isn’t always enough. Patients often face recurrence. But combining durvalumab with FLOT gives a significant boost in cancer control, helping more patients stay cancer-free for longer.