Abstract 3778: In vitro and in vivo characterization of E7090, a novel and selective FGFR inhibitor, for the treatment of endometrial cancer

Genetic abnormalities (gene fusion, mutation and amplification) of Fibroblast Growth Factor Receptor (FGFR) family members are known to cause constitutive activation of their signaling pathways, which play an important role in proliferation, survival and migration of cancer cells, tumor angiogenesis, and drug resistance. FGFR2 is mutated in about 10% of endometrial cancer patients and is associated with a higher risk of recurrence. E7090, an oral available FGFR1, 2, and 3 inhibitor that the chemical-structure and basic kinase inhibitory activity of this compound have been presented at AACR2015, is currently under a first-in-human study (NCT02275910) in Japan. In this presentation, the efficacy of E7090 against human endometrial cancer was examined. E7090 exhibited selective potent antiproliferative activity against 3 human endometrial cancer cell lines harboring FGFR2 mutation with IC50 values of approximately 10 nM among 8 endometrial cancer cell lines. These cell lines harbor S252W mutation (extracellular domain mutation; MFE280) or N549K mutation (kinase domain mutation; AN3CA and MFE296), that are the most common mutations of FGFR2 in endometrial cancer. E7090 also showed antiproliferative activity against Ba/F3 cells expressing mutated type of FGFR2, confirming the inhibitory activity of E7090 against mutated FGFR2. The antiproliferative activity of E7090 against these cell lines was based on inhibition of phosphorylated FRS2α and ERK1/2 as downstream molecules of FGF/FGFR signaling. Especially, the antiproliferative activities of E7090 against AN3CA and MFE296 harboring N550K mutation were more potent compared to these of other FGFR specific inhibitors. In addition, oral administration of E7090 resulted in significant tumor growth inhibition in MFE280, AN3CA and MFE296 xenograft models in mice. Especially, E7090 showed tumor regression in AN3CA xenograft model with a delta T/C value of -66% at a dose of 50 mg/kg. These results indicated that E7090 showed potent inhibitory activity against mutated type of FGFR2 both in vitro and in vivo, and suggest that E7090 may provide therapeutic opportunities for endometrial cancer harboring FGFR2 mutations. Citation Format: Saori Watanabe Miyano, Yuji Yamamoto, Kotaro Kodama, Naoko Hata Sugi, Yukinori Minoshima, Junji Matsui, Masao Iwata. In vitro and in vivo characterization of E7090, a novel and selective FGFR inhibitor, for the treatment of endometrial cancer. [abstract]. In: Proceedings of the 107th Annual M