Topline findings
- Imfinzi plus FLOT reduced the risk of death by 22% versus chemotherapy alone (HR 0.78; P=0.021).
- Three-year overall survival reached 69% with the Imfinzi regimen compared to 62% with FLOT alone.
- Pathologic response strongly correlated with improved event-free survival across all response categories.
- The survival benefit was consistent regardless of PD-L1 status or lymph node involvement.
- Imfinzi is the first immunotherapy to show statistically significant EFS improvement in resectable gastric and GEJ cancers.
AstraZeneca has shared new, positive data from the Phase III MATTERHORN clinical trial (NCT04592913) evaluating Imfinzi (durvalumab) in combination standard-of-care FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) chemotherapy. This latest readout shows the combination demonstrated a statistically significant and clinically meaningful improvement in the key secondary endpoint of overall survival (OS) compared to chemotherapy alone.1
Key overall survival results
Further results from the final OS analysis show:
- Imfinzi plus FLOT perioperative regimen reduced the risk of death by 22% versus chemotherapy alone (HR 0.78; 95% CI: 0.63–0.96; P=0.021).
- Median OS was not reached in either treatment arm.
- At three years, estimated survival was 69% with the Imfinzi-based regimen compared with 62% for FLOT alone.
In a press release, Josep Tabernero, MD, PhD, head of the Medical Oncology Department at the Vall d'Hebron University Hospital and director of the Vall d’Hebron Institute of Oncology (VHIO) in Barcelona, Spain, and principal investigator in the trial, said: “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. Nearly seven in 10 patients treated with the durvalumab-based perioperative regimen were alive at three years, and the survival benefit was observed regardless of PD-L1 status. With results like these, this novel treatment should become the new standard of care in this curative-intent setting.”
Pathologic outcomes and event-free survival
Additionally, AstraZeneca shared results from another analysis of the association between pathologic outcomes and event-free survival (EFS) in MATTERHORN.
- Pathologic response correlated with improved EFS in patients treated with Imfinzi versus the comparator.
- Hazard ratios for EFS by pathologic outcome were: Pathologic complete response (pCR) HR 0.29 (95% CI: 0.08–0.96), major pathologic response (MPR) HR 0.32 (95% CI: 0.15–0.68), and any pathologic response HR 0.60 (95% CI: 0.46–0.79).
- EFS benefit with Imfinzi was observed regardless of lymph node status at surgery (no nodal involvement HR 0.74; 95% CI: 0.46–1.18; nodal involvement HR 0.77; 95% CI: 0.58–1.02).
Trial design and methodology
The MATTERHORN trial is a randomized, double-blind, placebo-controlled, multi-center, global study evaluating Imfinzi as perioperative therapy in resectable Stage II-IVA gastric and gastroesophageal junction (GEJ) cancers.
