A phase I/II study of AZD6244 in combination with sorafenib in advanced hepatocellular carcinoma.

4100^ Background: Preclinical studies have shown that pharmacological inhibition of the MEK/ERK pathway by AZD6244 enhanced the anti-tumor effect of sorafenib in both orthotopic and ectopic models of HCC. We conducted this study to determine tolerability, pharmacokinetics, and pharmacodynamics of AZD6244 when combined with sorafenib in advanced HCC. Methods: Patients with biopsy-proven unresectable BCLC B/C hepatocellular carcinoma were recruited. Only those with Childs-Pugh A or B (7) liver cirrhosis and without prior systemic therapy were included. Sorafenib at 400mg bd was given 1 week before initiation of AZD6244 which was escalated in subsequent cohorts from 75mg om based on 3+3 design. PK and PD studies and QOL assessments were performed. DCE-MRI imaging was performed to assess tumor vascularity in response to treatment. Results: Fourteen patients were recruited (including 2 replaced). 11 had evaluable disease. Characteristics: all male, all Chinese, 12 were BCLC C stage. Two DLTs were seen out of 6 patients at dose level 1 (AZD6244 at 50mg bd) which were grade 3 fatigue and grade 3 abdominal pain with elevated transaminases. When an additional dose level 1A was added (ADZ6244 at 100mg om), 2 out of 3 patients had DLTs of grade 3 raised aspartate transaminase and grade 3 diarrhea. Thus, the MTD was determined to be AZD6244 at 75mg om when combined with sorafenib 400mg bd. Common toxicities were diarrhea (83%), rash (58%), fatigue (50%), hypertension (42%), anorexia/vomiting/thrombocytopenia (25%). Two patients had reversible LVEF dysfunction and there were no eye toxicities. PK of AZD6244 showed oral clearance of 11.2 + 6.8 L/h and terminal half-life of 6.0 +2.0 h.Objective responses were 3 PR, 6 SD and 2 PD.DCE-MRI measurements demonstrated significant reductions in permeability surface area product (PS, ml/100ml/min) and fractional intravascular blood volume (v1, ml/100ml) seven days after starting sorafenib. No additional antivascular activity was observed when AZD6244 was added to sorafenib. Conclusions: The recommended phase II dose for AZD6244 is 75mg om when combined with sorafenib 400mg bd for advanced HCC patients. This combination is feasible, shows activity and warrants further investigation.