Bemarituzumab as a First-Line Therapy for FGFR2b+ Advanced Gastroesophageal Cancer – A Subgroup Analysis of East Asian Patients from the FIGHT trial

Authors:
Kensei YAMAGUCHI,¹ Akira OOKI,¹ Yoon-Koo KANG,²Keun-Wook LEE,³ Li-Yuan BAI,⁴ Helen COLLINS,⁵ Yingsi YANG,⁵ Khalid MEZZI,⁵ Daniel CATENACCI,⁶ Peter ENZINGER,⁷ Zev WAINBERG,⁸


Affliations:
¹The Cancer Institute Hospital of JFCR, Koto-Ku, Tokyo, Japan
²Asan Medical Center, University of Seoul, Seoul, Republic of South Korea
³Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
⁴China Medical University, Taiwan
⁵Amgen Inc, Thousand Oaks, CA, USA
⁶Comprehensive Cancer Center, University of Chicago, Chicago, USA
⁷Dana Farber Cancer Institute, Boston, USA
⁸UCLA Department of Medicine, Hematology/Oncology, California, United States


Corresponding email address:
Kensei YAMAGUCHI (kensei.yamaguchi@jfcr.or.jp)

Background: The FIGHT (NCT03694522) study, a global phase-2 randomized, double-blind, showed that bemarituzumab, a humanized IgG1 mAb selectively binding to FGFR2b, improved PFS and OS in patients with FGFR2b+ gastric/gastroesophageal junction adenocarcinoma (GC/GEJ). Here, we present data from a subgroup analysis of East-Asian (Japan, South Korea, Taiwan) patients.

Methods: Eligible patients with previously untreated HER2-negative unresectable locally advanced/metastatic GC/GEJ were treated with mFOLFOX6 and randomized 1:1 to bemarituzumab 15mg/kg or placebo every two weeks with one additional 7.5mg/kg bemarituzumab/placebo dose on day 8, cycle 1. The primary endpoint was PFS; key secondary endpoints included OS, ORR, and frequency of AEs.

Results: Of the 62 randomized patients, 31 (50.0%) received bemarituzumab+mFOLFOX6, and 31 (50.0%) placebo+mFOLFOX6. Median PFS was 12.9 months (95% CI: 8.6–NR) for the bemarituzumab arm vs 8.4 months (95% CI: 6.8–12.1) for the placebo arm (HR: 0.52 [95% CI: 0.26–1.03]) in the intent-to-treat population. Median OS was NR (95% CI: 15.1–NR) for the bemarituzumab arm vs 15.9 months (95% CI: 10.2–not reached) for the placebo arm (HR: 0.53 [95% CI: 0.22–1.28]). The ORR was 57.9% (95% CI: 33.5%–79.7%) for the bemarituzumab arm vs 41.7% (95% CI: 22.1%–63.4%) in the placebo arm. Grade 3+ AEs were reported in 25 (83.3%) patients in the bemarituzumab arm vs 23 (74.2%) in the placebo arm. Corneal AEs were more common in the bemarituzumab arm (70.0% vs 12.9%) with 11 (18.0%) patients reporting grade 3+ corneal AEs vs none in the placebo arm. Overall, 25 (49.0%) pts received at least one new anticancer therapy (bemarituzumab, 10 [41.7%]; placebo, 15 [55.6%]).

Conclusion: Addition of bemarituzumab to mFOLFOX6 led to clinically meaningful improvements in PFS, OS, and ORR in East-Asian patients with FGFR2b+ GC/GEJ with an acceptable safety profile. The results support a prospective phase-3 study in East-Asian patients with GC/GEJ.