Lenvatinib causes reduced expression of carnitine/organic cation transporter 2 and carnitine deficiency in the skeletal muscle of rats

Effects of Lenvatinib on Skeletal Muscle Volume and Cardiac Function in Patients with Hepatocellular Carcinoma

INTRODUCTION

Previously, we reported that the tyrosine kinase inhibitor (TKI) sorafenib decreases serum levels of carnitine and reduces skeletal muscle volume. Moreover, others reported that TKIs might lead to cardiomyopathy or heart failure. Therefore, this study aimed to evaluate the effects of lenvatinib (LEN) on skeletal muscle volume and cardiac function in patients with hepatocellular carcinoma (HCC).

METHODS

This retrospective study included 58 adult Japanese patients with chronic liver diseases and HCC treated with LEN. Blood samples were collected before and after 4 weeks of treatment, and serum carnitine fraction and myostatin levels were measured. Before and after 4-6 weeks of treatment, the skeletal muscle index (SMI) was evaluated from computed tomography images and cardiac function was assessed by ultrasound cardiography.

RESULTS

After treatment, SMI, serum levels of total carnitine, and global longitudinal strain were significantly lower, but serum levels of myostatin were significantly higher. Left ventricular ejection fraction showed no significant change.

CONCLUSION

In patients with HCC, LEN decreases serum levels of carnitine, skeletal muscle volume, and worsens cardiac function.

L-carnitine prevents lenvatinib-induced muscle toxicity without impairment of the anti-angiogenic efficacy

Lenvatinib is an oral tyrosine kinase inhibitor that acts on multiple receptors involved in angiogenesis. Lenvatinib is a standard agent for the treatment of several types of advanced cancers; however, it frequently causes muscle-related adverse reactions. Our previous study revealed that lenvatinib treatment reduced carnitine content and the expression of carnitine-related and oxidative phosphorylation (OXPHOS) proteins in the skeletal muscle of rats. Therefore, this study aimed to evaluate the effects of L-carnitine on myotoxic and anti-angiogenic actions of lenvatinib. Co-administration of L-carnitine in rats treated with lenvatinib for 2 weeks completely prevented the decrease in carnitine content and expression levels of carnitine-related and OXPHOS proteins, including carnitine/organic cation transporter 2, in the skeletal muscle. Moreover, L-carnitine counteracted lenvatinib-induced protein synthesis inhibition, mitochondrial dysfunction, and cell toxicity in C2C12 myocytes. In contrast, L-carnitine had no influence on either lenvatinib-induced inhibition of vascular endothelial growth factor receptor 2 phosphorylation in human umbilical vein endothelial cells or angiogenesis in endothelial tube formation and mouse aortic ring assays. These results suggest that L-carnitine supplementation could prevent lenvatinib-induced muscle toxicity without diminishing its antineoplastic activity, although further clinical studies are needed to validate these findings.

The Role of Organic Cation Transporters in the Pharmacokinetics, Pharmacodynamics and Drug-Drug Interactions of Tyrosine Kinase Inhibitors

Tyrosine kinase inhibitors (TKIs) decisively contributed in revolutionizing the therapeutic approach to cancer, offering non-invasive, tolerable therapies for a better quality of life. Nonetheless, degree and duration of the response to TKI therapy vary depending on cancer molecular features, the ability of developing resistance to the drug, on pharmacokinetic alterations caused by germline variants and unwanted drug-drug interactions at the level of membrane transporters and metabolizing enzymes. A great deal of approved TKIs are inhibitors of the organic cation transporters (OCTs). A handful are also substrates of them. These transporters are polyspecific and highly expressed in normal epithelia, particularly the intestine, liver and kidney, and are, hence, arguably relevant sites of TKI interactions with other OCT substrates. Moreover, OCTs are often repressed in cancer cells and might contribute to the resistance of cancer cells to TKIs. This article reviews the OCT interactions with approved and in-development TKIs reported in vitro and in vivo and critically discusses the potential clinical ramifications thereof.

Impact of Cabozantinib Exposure on Proteinuria and Muscle Toxicity in Patients with Unresectable Hepatocellular Carcinoma

This prospective study investigated the impact of cabozantinib exposure on proteinuria and muscle toxicity, in a cohort of 14 Japanese patients with unresectable hepatocellular carcinoma (uHCC). We measured the trough concentration of cabozantinib (Ctrough) weekly for 6 weeks after starting treatment. Although the initial dose was less than 60 mg in most cases, dose interruption occurred in 79%, primarily because of proteinuria and/or malaise. The median and coefficient of variation of maximum Ctrough at 7−42 d were 929.0 ng/mL and 59.2%, respectively. The urinary protein-to-creatinine ratio (UPCR), serum creatine kinase, and serum aldolase values were all significantly elevated following treatment. Moreover, maximum changes in serum creatine kinase and aldolase were significantly associated with maximum Ctrough (r = 0.736, p < 0.01; r = 0.798, p < 0.001; respectively). Receiver operating characteristic (ROC) curve analysis showed that changes in serum creatine kinase ≥70.5 U/L and aldolase ≥6.1 U/L from baseline relatively accurately predicted inclusion in the high-maximum Ctrough (≥929.0 ng/mL) group, with an area under the ROC of 0.929 and 0.833, respectively. Measurement of serum creatine kinase and aldolase may increase the clinical usefulness of cabozantinib treatment for uHCC and help alleviate difficulties with dose adjustments.