Phase I study of intraperitoneal bevacizumab for treating refractory malignant ascites

OBJECTIVE: This prospective, dose-escalation phase I study evaluated the safety and efficacy of intraperitoneal bevacizumab in managing refractory malignant ascites and explored the recommended dose of bevacizumab for further study. METHODS: Patients with refractory malignant ascites were enrolled. Bevacizumab was intraperitoneal administered weekly at an initial dose of 2.5 mg/kg, with dose escalation to 5 and 7.5 mg/kg performed following the standard “3 + 3” rule. The total duration of treatment was 2 or 3 weeks. RESULTS: Between December 2013 and September 2014, 13 patients (2.5 mg/kg, n = 4; 5 mg/kg, n = 3; 7.5 mg/kg, n = 6) with refractory malignant ascites were enrolled. Bevacizumab was well tolerated, and the most common treatment-related adverse events were abdominal pain (5/13), abdominal distension (2/13), and fatigue (2/13). The dose-limiting toxicity at 7.5 mg/kg was grade 3 bowel obstruction (1/13). The maximum tolerated dose (MTD) was not reached. The overall response and disease control rates were 7.7 and 61.5%, respectively. CONCLUSIONS: Intraperitoneal bevacizumab safe and well tolerated for treating malignant ascites, and the MTD was not reached at doses of 2.5 to 7.5 mg/kg. Intraperitoneal bevacizumab at 7.5 mg/kg weekly is recommended for further study to verify its anti-tumor activity. Trial registration: Clinical Trials NCT01852409.