This is a single-center, randomized, open-label, two-period, crossover study consisting of two phases: Prerandomization and Randomization. The Prerandomization Phase will have two periods: Screening and Baseline 1. The Randomization Phase will have two periods: Treatment Period 1 and Treatment Period 2 with a Baseline 2 assessment prior to Treatment Period 2. In the Randomization Phase, subjects will be randomized to one of two possible treatment sequences (placebo/ketoconazole or ketoconazole/placebo). Ketoconazole 400 mg or placebo will be orally administered once daily for the first four days of each treatment period. On the fifth day of each treatment period, in addition to ketoconazole/placebo, 5 mg lenvatinib will be orally administered. Ketoconazole/placebo administration will then continue for 13 additional days. Subjects are crossed over from Treatment Period 1 to Treatment Period 2 after a 2-week washout.