Varying Impact of Lenvatinib or Sorafenib Therapy on Skeletal Muscle Loss in Patients with Hepatocellular Carcinoma

<b><i>Introduction:</i></b> Lenvatinib and sorafenib are key therapeutic agents for hepatocellular carcinoma (HCC). However, there are no useful biomarkers for selecting molecular-targeted agents (MTAs). Skeletal muscle volume is associated with the clinical outcomes in these patients. We investigated the effects of lenvatinib and sorafenib on the skeletal muscles of patients with HCC. <b><i>Methods:</i></b> We evaluated the impact of skeletal muscle changes over a 3-month period for each MTA (<i>n</i> = 117; lenvatinib/sorafenib, 45/72). The skeletal muscle mass index (SMI) was measured at the third lumbar vertebra. Furthermore, we evaluated the direct effect of each MTA on primary human skeletal muscle cells by estimating muscle protein synthesis using western blot analysis. <b><i>Results:</i></b> The median change in SMI was −0.7% (<i>p</i> = 0.959) and −5.9% (<i>p</i> &lt; 0.001) for the lenvatinib and sorafenib groups, respectively. Sorafenib had a greater effect on skeletal muscle loss than lenvatinib (<i>p</i> &lt; 0.001). Additionally, SMI significantly decreased in the sorafenib group regardless of initial skeletal muscle volume (<i>p</i> &lt; 0.001), whereas no significant differences were observed in the lenvatinib group. Sorafenib therapy (odds ratio [OR], 2.98; <i>p</i> = 0.023) and non-muscle depletion (OR, 3.31; <i>p</i> = 0.009) were associated with a decreased SMI. In vitro analysis showed that sorafenib negatively affected muscle synthesis compared to lenvatinib. <b><i>Conclusions:</i></b> Sorafenib may have a more negative effect on skeletal muscle than lenvatinib.