A Phase I study of safety and pharmacokinetics of fruquintinib, a novel selective inhibitor of vascular endothelial growth factor receptor-1, -2, and -3 tyrosine kinases in Chinese patients with advanced solid tumors

Fruquintinib (HMPL-013) is a novel oral small molecule compound that selectively inhibits vascular endothelial growth factor receptors-1, -2, and -3 with potent inhibitory effects on multiple human tumor xenografts. This first-in-human study was conducted to assess the maximum tolerated dose and dose-limiting toxicities, safety and tolerability, pharmacokinetics, and preliminary anti-tumor activity of fruquintinib. Patients 18–70 years old with advanced solid tumors refractory to standard therapies were recruited. Fruquintinib was administered orally in 4-week repeating cycles in two regimens, either once daily continuously or once daily for 3-week on/1-week off, until discontinuation due to toxicity or tumor progression. Adverse events were assessed using National Cancer Institute Common Terminology Criteria for Adverse Events v4.0.3. Pharmacokinetic parameters were measured after a single dose and in multiple dosing. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors v1.0. Forty patients were enrolled into 5 cohorts in continuous regimen and 2 cohorts in 3-week-on/1-week-off regimen. The most common grade 3/4 adverse events were hand–foot skin reaction, hypertension, and thrombocytopenia. PK analysis showed good and rapid absorption followed by slow terminal elimination with a mean half-life of approximately 42 h which was consistent across all dose groups. Thirty-four patients were evaluable for tumor response, including 14 with partial response and 14 with stable disease. Fruquintinib showed an acceptable safety profile and preliminary evidence of anti-tumor activity in patients with advanced solid tumors. The recommended dose was determined to be either 4 mg QD on a continuous regimen or 5 mg QD on a 3-week-on/1-week-off regimen.