SAT-039 The Short-Term Effect of Multiple Kinase Inhibitor (Lenvatinib) on Spermatogenesis in Mice

Lenvatinib, a multi-kinase inhibitor, is used in the treatment of solid malignancies. Lenvatinib belongs to a family of tyrosine kinase inhibitors and targets VEGF receptors 1-3, FGF receptors 1-4, PDGF receptor alpha, RET and KIT. However, it is not known whether Lenvatinib like other chemotherapeutic drugs affects spermatogenesis. The objective of this study was to examine whether Lenvatinib induces damage to spermatogenesis in mice. Twenty adult mice (C57BL/6) were randomly divided into 2 groups to receive daily gavage of either water (as control) or Lenvatinib (10 mg/kg) for 6 weeks. All mice were euthanized at the end of the study. We identified that Lenvatinib significantly (p<0.05) decreased testis weight (TW: 91.75±1.49mg) compared to control mice (TW: 111.9±3.07mg). This difference in testis weight however, became non-significant after correcting for body weight. The cauda epididymal sperm count was significantly (p<0.01) decreased in the Lenvatinib treated (0.82±0.04 million/mg cauda) as compared to control (1.26±0.07 million/mg cauda) mice. There were no differences in plasma testosterone concentrations between Lenvatinib treated (29.76±7.67ng/dl) and control (31.72±6.89ng/dl) mice. Lenvatinib did not induce notable morphological changes in testicular histology. We conclude that 6 weeks of Lenvatinib treatment had minimal effect if any on mouse spermatogenesis. The long-term treatment effect of Lenvatinib on spermatogenesis remains to be determined.