BALTIMORE—Waging war against advanced gastric cancers, Personal Genome Diagnostics Inc. (PGDx) is collaborating with Five Prime Therapeutics Inc. to develop a plasma-based companion diagnostic assay for use with Five Prime’s investigational drug candidate, bemarituzumab (FPA144), a first-in-class antibody targeting fibroblast growth in cancer patients.
The FIGHT Phase 1/3 clinical trial is a global registrational study in patients with advanced gastric or gastroesophageal junction cancer whose tumors overexpress FGFR2b or have FGFR2 gene amplification.
The collaboration calls for PGDx to develop and validate a plasma-based circulating tumor DNA (ctDNA) in-vitro diagnostic (IVD) assay to help identify patients whose tumors are FGFR2 gene-amplified and therefore eligible for treatment with bemarituzumab in the Phase 3 portion of the FIGHT trial, which is expected to begin in the second half of 2018.
Financial terms of the agreement were not disclosed.
PGDx intends to submit the companion diagnostic for regulatory approval and commercialize it in the U.S., Europe and Asia—the latest example of PGDx's strategy of working with cancer drug developers to provide companion diagnostics in the form of regulated, standardized IVD kits, available to patients around the globe.
The company is not disclosing the details of its strategy, but aims to have its first product to market by early 2019, with others soon following.
“At PGDx, our mission is to empower the fight against cancer by unlocking actionable information from the genome,” says Doug Ward, CEO of PGDx. “We are committed to developing a portfolio of regulated tissue-based and liquid biopsy genomic products for laboratories worldwide.”
PGDx is “fortunate to have a range of partners, from global pharmaceutical leaders to innovative new biotech drug developers,” Ward adds. “We are delighted to be collaborating with Five Prime on this important new product addressing gastric cancers with very high unmet need for improved therapies.”
PGDx “has been working with large pharmaceutical companies since our earliest days, but we also see biotech innovators such as Five Prime as key partners for our advanced capabilities in developing companion diagnostics for targeted and immuno-oncology therapies,” Ward says. “Five Prime’s bemarituzumab has shown encouraging activity against important genetic variants of certain gastric cancers that lack effective treatment options.”
“We see standardized, regulated IVD genomic tests that can be performed locally by most laboratories as the future of genomic testing,” he says. “Variations in cancer genomic testing results from lab to lab are a fact of life and a valid concern, but will persist until testing is standardized.”
Adds Ward: “Our first pipeline products focus on tissue-based and plasma tests for microsatellite instability and tumor mutational burden, which we were among the first to market via our CLIA lab, as well as multigene plasma tests for cancer. Other genomic cancer assays, including companion diagnostics, will follow.”
Ward also sees recent actions by the U.S. Food and Drug Administration to update the review of diagnostic products as a positive for the cancer genomics field and looks forward to working with the agency as the company’s programs advance.
Aron Knickerbocker, CEO of Five Prime Therapeutics, says, “We are pleased to collaborate with PGDx, a cancer genomics pioneer with a wealth of experience in accurately identifying genomic alterations in tumors. Patients with advanced gastric and gastroesophageal junction cancer need new treatment options.”
“At Five Prime, we want to fundamentally improve the lives of patients with serious diseases in ways never before possible,” he adds. “We are focused primarily on therapies for cancer and have three drug candidates in active human clinical trials. We are also focusing our earlier-stage research efforts on immuno-oncology.”
Five Prime plans to use immunohistochemistry and ctDNA tests to identify the estimated 10 percent of patients with gastric and gastroesophageal junction cancer whose prognosis has been particularly poor—and who would also be eligible for treatment with bemarituzumab.
"For patients whose tumors overexpress FGFR2b or have FGFR2 gene amplification, prognosis has been found to be particularly poor, so we are hopeful that a targeted therapy like bemarituzumab may provide a clinical benefit in this setting,” he says.
According to Decision Resources and ZS Associates, the Asian market is sizable. In fact, China, with 474,000 first-line patients, makes up more than 40 percent of the cases worldwide. Europe follows with 153,100 first-line patients, followed by 134,300 patients in Japan/Korea and 28,400 in the United States. Only 10 percent of each group have been deemed treatment eligible. The 2014 World Cancer Report states gastric cancer is the fifth leading cause of cancer and the third leading cause of death from cancer.
