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.