Clinical activity observed in a phase I dose escalation trial of an oral c-met and ALK inhibitor, PF-02341066.


3509 Background: PF-02341066 (PF) is a selective, ATP-competitive, small molecule oral inhibitor of the c-Met/HGFR and ALK receptor tyrosine kinases that has not previously been tested in humans. A Phase 1 dose-escalation trial evaluating PF as an oral single agent was conducted to investigate safety, PK and PD in patients (pts) with advanced cancer (excluding leukemias). METHODS PF was administered under fasting conditions QD or BID on a continuous schedule to pts in successive dose-escalating cohorts at doses ranging from 50 mg QD to 300 mg BID. Pts with advanced cancer were enrolled in the study. RESULTS Thirty-seven pts were enrolled into the dose escalation part of the study. Tumor types included colorectal, pancreatic, sarcoma, ALCL and NSCLC. The MTD was 250 mg BID. Three DLTs were observed: grade 3 increase in ALT (1 pt at 200 mg QD) and grade 3 fatigue (2 pts at 300 mg BID). The most common AEs were nausea, emesis, fatigue and diarrhea. Nausea and emesis were independent of dose or duration of treatment. Mean AUC (30-57% CV) and Cmax (36-69% CV) increased proportionally with dose from 100 mg QD to 300 mg BID. The median terminal half-life was 46 hours. A 2- to 4-fold increase in the oral midazolam (MDZ) AUC was observed following 28-days of PF dosing at 100 mg QD (n = 3) and 300 mg BID (n = 2), respectively, suggesting PF to be an inhibitor of CYP3A. Ten pts have entered an enriched RP2D cohort of pts with tumors harboring c-Met amplification/gene mutation or ALK fusion genes. There has been 1 confirmed PR in a sarcoma pt with ALK rearrangement (inflammatory myofibroblastic tumor). Among 10 NSCLC pts whose tumors harbor EML4-ALK rearrangement, 1 pt has had a PR, 2 pts have achieved unconfirmed PR and 4 pts have had SD (3 have experienced reduction in tumor burden by ∼20% in measurable lesions and 1 has been treated for 28 weeks). CONCLUSIONS The MTD of PF is 250 mg BID. The major AEs were fatigue or GI-related, and all AEs were manageable and reversible. There was no evidence of non-linear PK at PF doses >100 QD. Treatment with PF-02341066 resulted in promising clinical activity against tumors carrying activating ALK gene rearrangements. Further study of PF in pts with ALK-dependent tumors is warranted. [Table: see text].


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