Exploratory analysis of early toxicity of sunitinib in advanced hepatocellular carcinoma patients: Kinetics and potential biomarker value

Purpose: Sunitinib - a multitargeted tyrosine kinase inhibitor - can modulate circulating inflammatory factors in cancer patients that may be relevant for hepatocellular carcinoma (HCC) progression. However, a recent phase III study of sunitinib in HCC was halted due to its toxicity. Here, we studied the early kinetics of adverse events after sunitinib, and explored their association with circulating proteins and clinical outcome in advanced HCC in a single-arm phase II study. Experimental Design: Toxicity was evaluated every two weeks during the first cycle of therapy. Biomarker changes from baseline were tested after adjusting for multiple comparisons. Correlation between toxicities and overall survival (OS) or time-to-tumor progression (TTP) was evaluated in a Cox model using log-transformed levels or change in biomarkers, after stratifying by stage and adjusting for baseline level. Results: Myeloid and lymphoid blood cell counts decreased by 20% to 50% after sunitinib treatment (P < 0.05 for all). The extent of the early decrease in neutrophils and monocytes, and the development of nonhematologic toxicities (i.e., skin toxicities), were significantly associated with both OS and TTP (P < 0.05). Changes in circulating cells significantly associated with specific changes in plasma biomarkers (i.e., changes in platelets with changes in VEGF-C and soluble-VEGFR3; changes in neutrophils with changes in IL-8, TNF-α, and soluble-VEGFR2). Conclusions: The adverse effects of sunitinib, particularly on the hematopoietic system, may be rapid and appear directly related to its activity in HCC. This exploratory study suggests that early hematopoietic toxicities may potentially predict outcome in advanced HCC after sunitinib treatment.