Infection risk in breast cancer patients treated with trastuzumab: a systematic review and meta-analysis

Infections related to anti-HER2 monoclonal antibodies (mAbs), trastuzumab and pertuzumab, have been reported in clinical trials. It is not yet clear whether these drugs increase an infection risk or not. We performed a systematic review and meta-analysis to assess the risk of infections associated with anti-HER2 mAbs. We searched PubMed and the ASCO online database of meeting abstracts up to January 2014 for relevant clinical trials. Eligible studies included randomized controlled trials of trastuzumab or pertuzumab for breast cancer patients that reported adequate safety data for grade 3-4 infection, febrile neutropenia, neutropenia, or leukopenia. The summary incidence, relative risk (RR), and 95 % confidence intervals (CIs) were calculated. A total of 10,094 patients from 13 trials were included. The use of trastuzumab was associated with an increased risk of high-grade infection (RR 1.21, 95 % CI 1.07-1.37, P = 0.002) and febrile neutropenia (RR 1.28, 95 % CI 1.08-1.52, P = 0.004). The incidence of high-grade infection and febrile neutropenia due to trastuzumab was 8.5 % (95 % CI 4.5-15.4 %) and 12.0 % (95 % CI 8.1-17.4 %), respectively. There was no significant increase in a risk of high-grade neutropenia or leukopenia in patients receiving trastuzumab. Treatment with trastuzumab is associated with a significantly higher risk of high-grade infection and febrile neutropenia. Our findings suggest an importance of close monitoring for any signs of infections in patients treated with trastuzumab.