Bemarituzumab (FPA144)

Bemarituzumab (FPA144) is a first-in-class anti-FGF receptor 2b (FGFR2b) humanized monoclonal antibody in clinical development as a targeted immune therapy for tumors that over-express FGFR2b. We estimate approximately 10% of gastric cancer patients have tumors that overexpress the FGFR2b protein, which is associated with poor prognosis.

fpa144mechanism

Bemarituzumab (FPA144) is designed to block tumor growth through two distinct mechanisms:

  • First, it binds specifically to FGFR2b and prevents the binding of certain fibroblast growth factors (FGF7, 10 and 22) that promote tumor growth.
  • Second, it has been engineered to drive immune-based killing of tumor cells by antibody-dependent cell-mediated cytotoxicity (ADCC) through the recruitment of natural killer (NK) cells.

Preclinical studies have shown that bemarituzumab (FPA144) is highly effective in blocking the growth of gastric cancers that produce abnormally high levels of FGFR2b. Preclinical studies in models of gastric cancer have also shown that bemarituzumab (FPA144) has additive activity in combination with chemotherapy.

Bemarituzumab (FPA144) Status

Gastric Cancer

Bemarituzumab (FPA144) has demonstrated monotherapy activity in gastric cancer in our ongoing Phase 1 clinical trial (NCT02318329).  However, we believe combination therapy will provide the greatest patient benefit to patients with gastric cancer.

In December 2017, the company initiated dosing in the Phase 1 safety lead-in portion of the FIGHT Phase 1/3 clinical trial (NCT03343301) of bemarituzumab (FPA144) in combination with the mFOLFOX6 chemotherapy regimen in patients with previously untreated, advanced gastric or gastroesophageal cancer. The safety lead-in is intended to support the start of the global Phase 3 randomized clinical trial comparing bemarituzumab (FPA144) combined with mFOLFOX6 versus mFOLFOX6 alone in for the front-line treatment of patients with metastatic gastric and gastroesophageal junction cancer whose tumor overexpress FGFR2b.

In December 2017, we and Zai Lab announced a collaboration for the development and commercialization of bemarituzumab (FPA144) in Greater China. Zai Lab will manage the Phase 3 portion of the FIGHT trial in China.

In addition, we launched a Phase 1 safety trial for bemarituzumab (FPA144) monotherapy in patients with gastric cancer in Japan, where the incidence of gastric cancer is high. Completion of this Phase 1 trial is intended to enable the inclusion of Japanese patients in the FIGHT trial.

We are developing companion diagnostics to identify the approximately 10% of gastric cancer patients eligible for bemarituzumab (FPA144) therapy in the FIGHT trial. We plan to use either immunohistochemistry (IHC) or circulating tumor DNA (ctDNA) tests to identify eligible patients.

In July 2016, the U.S. Food and Drug Administration (FDA) granted bemarituzumab (FPA144) Orphan Drug Designation for the treatment of gastric cancer, including cancer of the gastroesophageal junction.

Globally, gastric cancer is the sixth most common malignancy with the third highest mortality. The prevalence of gastric cancer worldwide is approximately 1.5 million patients, of which we estimate 10%, or approximately 150,000 patients, have tumors that overexpress FGFR2b. 

Bladder Cancer

Beyond the gastric cancer setting, we are also studying bemarituzumab (FPA144) in patients with bladder cancer whose tumors overexpress FGFR2b. According to our research, approximately 14% of tumor samples from patients with metastatic bladder cancer overexpress FGFR2b as assessed by our immunohistochemistry (IHC) test.