CyFi: A phase I study exploring the role of cMET pathway inhibition with ficlatuzumab (Fi) combined with high-dose cytarabine (Cy) in patients with high risk relapsed or refractory acute myeloid leukemia (AML).

Abstract

7040 Background: Pts with AML who are refractory to induction therapy or relapse within 1 year have poor outcomes. Elevated serum HGF level is an adverse prognostic factor in AML (Verstovsek, et al. 2001; Kim, et al. 2005). Pre-clinical models have shown that myeloid blasts produce HGF in an autocrine fashion and pharmacologic blockade of the HGF/c-Met axis sensitizes blasts to cell death (Kentsis, et al. 2012). Methods: We initiated a phase I study to assess the safety and tolerability of Fi combined with Cy in patients with AML who are refractory to 7+3 or have relapsed within 1 year of induction. Fi is given in escalated dosing of 10, 15, or 20 mg/Kg for 4 doses every 2 weeks, starting on day 0, and Cy at a fixed dose of 2g/m2 on days 2-7, using a 3x3 design. PBMCs, BM and serum are collected at defined time points to assess HGF levels and activation of the c-Met pathway. Results: Dose escalation is complete and there were no protocol-defined DLTs identified in 9 evaluable pts. All pts treated to date were refractory to induction. Four had de novo AML; 2 had undifferentiated leukemia; 2 prior MDS; 1 prior MPN. Most frequent grade 3/4 TEAEs were febrile neutropenia (56%), LFT abnormalities (11%), and electrolyte disturbance (11%). There was 1 death (11%) from sepsis and multi-organ failure on day 23, following ANC recovery. Of the 7 evaluable pts, 3 achieved a CR (43%), all in the 2nddose cohort. Two of the 3 CRs are long lasting 11 and 12 months following AlloHCT. All patients had detectable circulating HGF levels at baseline compared to control subjects without AML. HGF levels increased following exposure to Fi by an average of 193%. Baseline HGF levels or change from baseline were not associated with treatment response. Conclusions: Ficlatuzumab can be safely combined with HiDAC in this high-risk AML population and produce durable clinical responses. Circulating HGF levels were detectable at baseline and uniformly increased with treatment suggestive of a feedback response or immune complex stabilization. Dose expansion is ongoing. Clinical trial information: NCT02109627.