Design: Global, randomised, double-blind, placebo-controlled, phase 3 trial (MATTERHORN)
Population: 948 adults with resectable stage II–IVa gastric or gastro-oesophageal junction adenocarcinoma
Primary outcome: Overall survival (key secondary; event-free survival was the primary)
Effect: Hazard ratio 0.78 (95% CI 0.63–0.96), P=0.021

MATTERHORN randomised 948 patients with resectable stage II–IVa gastric or gastro-oesophageal junction adenocarcinoma to perioperative durvalumab added to FLOT chemotherapy or to FLOT with placebo, across 147 centres in 20 countries. Event-free survival and pathological response favoured durvalumab in earlier reports; this is the overall-survival readout.

Overall survival improved with durvalumab (hazard ratio 0.78, 95% CI 0.63–0.96). Treatment-related deaths were rare and similar between groups (1% vs under 1%). The investigators call the regimen a new standard option in this setting.

Gastric and junctional cancers are common in parts of India and often present when still resectable, so the population is relevant; the constraint is access, as durvalumab is costly and not universally funded. The chemotherapy backbone, FLOT, is unchanged.

Adding perioperative durvalumab to FLOT improved overall survival in resectable gastric and junctional cancer.
The survival hazard ratio was 0.78, on top of the earlier event-free survival benefit.
Treatment-related deaths were rare and comparable to chemotherapy alone.
The main barrier to use is cost and funding, not the evidence.

Why it matters

It moves immunotherapy into the curative-intent, perioperative setting for a cancer where survival gains have been hard to find.

The statistics, in plain English

A hazard ratio of 0.78 is a 22% lower death rate; the interval (0.63–0.96) stays below 1.0, so the overall-survival benefit is statistically secure, confirming the earlier event-free survival result.