Definition

An orally bioavailable, selective inhibitor of human fibroblast growth factor receptor 3 (FGFR3), with potential antineoplastic activity. Upon oral administration, FGFR3 inhibitor LOXO-435 specifically targets and binds to FGFR3, including FGFR3 gatekeeper resistance mutations. This blocks FGFR3-mediated signaling and leads to an inhibition of tumor cell proliferation in FGFR3-overexpressing cells. FGFR3, a receptor tyrosine kinase, is involved in angiogenesis and in the proliferation, differentiation, and survival of tumor cells. FGFR3 expression is associated with poor prognosis. It is overexpressed and/or mutated by certain tumor cell types.