Bevacizumab did not reduce the risk of anemia associated with chemotherapy: an up-to-date meta-analysis

The risk of anemia due to bevacizumab-based chemotherapy has not been well described, and new randomized controlled trials (RCTs) have been reported in recent years. We therefore conducted an up-to-date meta-analysis of RCTs to fully characterize the risk of anemia with bevacizumab. We carried out an electronic search of Medline, Embase, and The Cochrane Central Register of Controlled Trials to investigate the effects of RCTs on bevacizumab treatment on cancer patients up to October 2014, and random or fixed-effect meta-analytical models were used to assess the risk ratio (RR) of anemia due to the use of bevacizumab according to the heterogeneity of included studies. A total of 13,173 patients were included in this analysis from 18 RCTs. Among those patients receiving bevacizumab and chemotherapy, the incidences of all-grade and high-grade (grade 3 and above) anemia were 24 % (95 % confidence interval (CI) 13-41 %) and 4.0 % (95 % CI 3.0-6.0 %), respectively. Bevacizumab-containing therapy did not significantly decreased the risk of developing all-grade anemia (RR 0.872, 95 % CI 0.739-1.029, P = 0.104) and high-grade anemia (RR 0.850, 95 % CI 0.720-1.002, P = 0.053), which is not in agreement with previous meta-analysis. On subgroup analysis, we did not find significant risk differences based on bevacizumab dosage, tumor types, and concomitant drugs. When stratified by dose level, a significantly decreased risk of high-grade anemia with bevacizumab was obtained in a lower dose level (2.5 mg/kg/week, RR 0.773, 95 % CI 0.611-0.978, P = 0.031) compared to control group. Bevacizumab did not significantly reduce the risk of anemia with chemotherapy in cancer patients.