According to a subgroup analysis of the MATTERHORN study, the benefit to pathological complete response (pCR) of adding durvalumab to 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) chemotherapy among patients with gastric or gastroesophageal junction cancer (GC/GEJC) was seen consistently across all geographic regions.

These results were presented by Yelena Janjigian, MD, Memorial Sloan Kettering Cancer Center, New York, NY, at the 2024 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium on Thursday, January 18, 2024, in San Francisco, California.

In the global, double-blind, phase 3 MATTERHORN study, 948 patients with GC/GEJC were randomized on a 1-to-1 basis to receive either 1500 mg durvalumab or placebo every 4 weeks on day 1, plus FLOT twice a week on days 1 and 15, for 4 cycles, followed by durvalumab or placebo 4 times a week for 10 further cycles. Randomization was stratified by patients in Asia vs non-Asia. At the first interim analysis, it was reported that durvalumabt plus FLOT significantly improved the pCR among patients with GC/GEJC when compared to placebo plus FLOT. In this subgroup analysis, the pCR was evaluated in the pre-specified Asia subgroup, as well as other post hoc regional subgroups of the 6 countries with the highest number of patients randomized (Germany, Spain, Poland, US, and Brazil).

There were 180 patients (19%) from Asia and pCR outcomes among those patients were consistent with the global outcomes. In all regions, durvalumab plus FLOT improved pCR outcomes when compared with placebo plus PLOT, though there were baseline characteristic imbalances and several numerical differences in the pCR rates by geographic location. In the Germany subgroup, the pCR rate of those treated with durvalumab plus FLOT was similar to the pCR rate seen with FLOT in the initial FLOT-4 trial. The improvement to pCR with durvalumab plus FLOT was seen across all geographical subgroups. Additionally, the combined complete and near-complete response rates had similar trends across all subgroups.

According to Dr Janjigian and coauthors, “pCR was consistently improved with the addition of [durvalumab] to perioperative FLOT in GC/GEJC across geographic regions.” The study is ongoing, and the primary objective of event-free survival has not yet been reported.

Source:

Janjigian YY, Al-Batran S, Wainberg ZA, et al. Pathological complete response (pCR) to 5-fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT) with or without durvalumab (D) in resectable gastric and gastroesophageal junction cancer (GC/GEJC): Subgroup analysis by region from the phase 3, randomized, double-blind MATTERHORN study. Presented at 2024 ASCO Gastrointestinal Cancer Symposium; January 18-20, 2024; San Francisco, California. Abstract LBA246