MATTERHORN, a Phase III trial conducted globally, is randomized and assesses IMFINZI as a perioperative treatment for individuals with resectable Stage II-IVA gastric and gastroesophageal cancers. Perioperative therapy, involving both pre-and post-surgery treatment (neoadjuvant/adjuvant therapy), is under evaluation. An interim analysis, planned, took place once all randomized patients either underwent surgery or were ineligible. The assessment included evaluating the superiority of the pCR rate and examining surgical and safety outcomes.

As per the data cut-off on February 1, 2023, both treatment arms in the study included 474 patients with balanced baseline characteristics, with 19% of participants from Asia in both groups. Data from ESMO Asia revealed a statistically significant improvement in pathological complete response (pCR) with the addition of IMFINZI to FLOT compared to placebo added to FLOT. The central review indicated a 12% absolute difference in the pCR rate, while the investigator assessment showed a 13% difference. The combined pCR/near-complete pathological response (pnCR) rate was notably higher with IMFINZI-FLOT at 27%, surpassing the 14% observed with a placebo. Surgery and R0 resection rates for patients undergoing surgery were comparable between IMFINZI-FLOT and placebo (87% and 86%, respectively). IMFINZI also demonstrated favorable downstaging compared to the placebo group. The incidence of adverse events was similar between the two arms, and there were no new safety concerns identified for the combination of durvalumab plus FLOT.

The results from the MATTERHORN study emphasize the potential benefits of introducing a combined early-stage treatment strategy involving immunotherapy and chemotherapy for individuals diagnosed with gastric and gastroesophageal junction cancers.

Conclusion

MATTERHORN represents the pioneering global Phase III, double-blind study evaluating peri-operative durvalumab plus FLOT in individuals with resectable GC/GEJC. In this pre-planned interim analysis, the addition of durvalumab to peri-operative FLOT exhibited a statistically significant and clinically meaningful enhancement in pathological complete response (pCR) compared to placebo plus FLOT, showcasing a substantial 12% absolute difference in pCR rate. There was also a notable improvement in downstaging, characterized by more participants achieving T0 and N0 compared to the placebo plus FLOT group. Adverse event incidence was comparable between the two arms, with observed events aligning with expectations, and no new safety concerns identified for the durvalumab plus FLOT combination. The MATTERHORN study is currently underway, focusing on its primary objective of Event-Free Survival (EFS).

The incidence of gastroesophageal junction cancer is on the rise. At the time of diagnosis, around 40% of patients have metastatic disease, and their 5-year overall survival is low. Owing to the high prevalence of H. pylori infection, certain dietary practices, smoking habits, and strong alcohol intake.

For more insight into the patient's burden, epidemiological factors, treatment options, and evolving developments in the market landscape, refer to the Gastroesophageal Junction Adenocarcinoma Market Insight, Epidemiology and Market Forecast and Gastric Cancer Market Insight, Epidemiology, And Market Forecast