Gahlemann, C. G.

TPS597 Background: Deregulation of the FGFR signaling pathway is implicated in various cancers. In iCCA, FGFR genetic aberrations include FGFR2 fusions and, less commonly, FGFR2 M/A. iCCA prognosis is poor, and chemotherapeutic and targeted treatment options are limited. While FGFR2 fusions are acknowledged oncogenic drivers, the oncogenic potential of FGFR2 M/A is less well defined. Derazantinib (DZB) is an investigational, oral small-molecule kinase inhibitor with activity against FGFR1, 2 and 3, which demonstrated antitumor activity in patients with unresectable iCCA with FGFR2 fusions. Based on preliminary efficacy data demonstrating durable responses of > 6 months and a clinically meaningful progression-free survival in a subset of iCCA patients harboring FGFR2 M/A (NCT01752920), the multicenter, multicohort open-label phase 2 study FIDES-01 is evaluating the effect of DZB in separate cohorts of iCCA patients with FGFR2 fusions or FGFR2 M/A. Methods: The new cohort evaluates 300 mg once daily dosing of DZB in patients with unresectable iCCA with FGFR2 M/A per liquid or tissue biopsy-based next generation sequencing and at least one previous systemic therapy. Treatment will continue until progressive disease, intolerance, withdrawal of informed consent, or death. Using a Simon’s two-stage design, the primary endpoint to assess the antitumor activity of DZB is the proportion of patients with PFS at 3 months (PFS3; per RECIST 1.1 central review). Secondary objectives are evaluation of median PFS, objective response rate, duration of response, safety profile, quality of life (incl., QLQ-C30, QLQ-BIL21, EQ-5D), and symptom response from baseline. Current status: The study was initiated in July 2019 with planned enrollment of 43 patients with confirmed FGFR2 M/A. Clinical trial information: NCT03230318.