Amgen's Gastric Cancer Treatment Bemarituzumab Meets Primary Endpoint in Phase 3 Trial

Amgen's gastric cancer treatment, bemarituzumab, met its primary endpoint in a Phase 3 trial, showing a statistically significant and clinically meaningful improvement in overall survival when used in combination with chemotherapy. The study focused on patients with certain types of gastric or gastroesophageal junction cancer. A Phase 3 study of bemarituzumab with nivolumab is ongoing and data is expected later this year.

Amgen's bemarituzumab, an FGFR2b inhibitor, has shown promising results in a Phase 3 trial for gastric cancer. The Phase 3 FORTITUDE-101 study, which evaluated bemarituzumab plus chemotherapy (mFOLFOX6) versus placebo plus chemotherapy as first-line therapy for advanced gastric or gastroesophageal junction (G/GEJ) cancer with FGFR2b overexpression, met its primary endpoint of overall survival (OS).

The study, conducted at 300 sites across 37 countries and involving 547 patients, demonstrated a statistically significant and clinically meaningful improvement in OS for patients treated with bemarituzumab plus chemotherapy compared to those treated with placebo plus chemotherapy. The trial was designed to include patients with unresectable locally advanced or metastatic gastric or G/GEJ cancer who were non-HER2 positive and had FGFR2b overexpression defined as 2+/3+ staining in ≥10% of tumor cells by centrally performed immunohistochemistry (IHC) testing.

Gastric cancer is a significant global health issue, with nearly one million new cases and over 650,000 deaths annually [1]. The disease is particularly prevalent in China, with over 350,000 new cases each year. The five-year survival rate for advanced gastric cancer is less than 10%, highlighting the critical need for effective treatments.

"Bemarituzumab is the first FGFR2b inhibitor to demonstrate a statistically and clinically significant overall survival benefit in a randomized Phase 3 trial for the first-line treatment of FGFR2b-positive gastric cancer," said Dr. Rafael Amado, M.D., President, Head of Global Research and Development at Zai Lab. "The success of the global Phase 3 FORTITUDE-101 study highlights the potential of bemarituzumab to redefine the standard of care for a patient population that has faced poor outcomes with existing therapies."

The most common treatment-emergent adverse events (25%) in patients treated with bemarituzumab plus chemotherapy were reduced visual acuity, punctate keratitis, anemia, neutropenia, nausea, corneal epithelium defect, and dry eye. While ocular events were consistent with the Phase 2 experience and observed in both arms, they occurred with greater frequency and severity in the Phase 3 bemarituzumab arm.

The Phase 3 study of bemarituzumab plus chemotherapy and nivolumab is ongoing and data readout is anticipated in the second half of 2025. Zai Lab holds the development and commercialization rights for bemarituzumab in mainland China, Hong Kong, Macau, and Taiwan. Bemarituzumab has been granted Breakthrough Therapy designation by the China Center for Drug Evaluation of the National Medical Products Administration for the treatment of FGFR2b-positive gastric and gastroesophageal junction adenocarcinoma.

References:
[1] Bray F, et al. CA Cancer J Clin. 2024;74(3):229-263.