Safety, pharmacokinetics, and antitumor properties of anlotinib, an oral multi-target tyrosine kinase inhibitor, in patients with advanced refractory solid tumors

Anlotinib is a novel multi-target tyrosine kinase inhibitor that is designed to primarily inhibit VEGFR2/3, FGFR1-4, PDGFR α/β, c-Kit, and Ret. We aimed to evaluate the safety, pharmacokinetics, and antitumor activity of anlotinib in patients with advanced refractory solid tumors. Anlotinib (5-16 mg) was orally administered in patients with solid tumor once a day on two schedules: (1) four consecutive weeks (4/0) or (2) 2-week on/1-week off (2/1). Pharmacokinetic sampling was performed in all patients. Twenty-one patients were further enrolled in an expanded cohort study on the recommended dose and schedule. Preliminary tumor response was also assessed. On the 4/0 schedule, dose-limiting toxicity (DLT) was grade 3 hypertension at 10 mg. On the 2/1 schedule, DLT was grade 3 hypertension and grade 3 fatigue at 16 mg. Pharmacokinetic assessment indicated that anlotinib had long elimination half-lives and significant accumulation during multiple oral doses. The 2/1 schedule was selected, with 12 mg once daily as the maximum tolerated dose for the expanding study. Twenty of the 21 patients (with colon adenocarcinoma, non-small cell lung cancer, renal clear cell cancer, medullary thyroid carcinoma, and soft tissue sarcoma) were assessable for antitumor activity of anlotinib: 3 patients had partial response, 14 patients had stable disease including 12 tumor burden shrinkage, and 3 had disease progression. The main serious adverse effects were hypertension, triglyceride elevation, hand-foot skin reaction, and lipase elevation. At the dose of 12 mg once daily at the 2/1 schedule, anlotinib displayed manageable toxicity, long circulation, and broad-spectrum antitumor potential, justifying the conduct of further studies.