Adverse drug events associated with ibrutinib for the treatment of elderly patients with chronic lymphocytic leukemia A systematic review and meta-analysis of randomized trials

Background: Chronic lymphocytic leukemia (CLL) is a rare hematological malignancy classified in the non-Hodgkin's lymphoma category. Ibrutinib, a first-in-class Bruton tyrosine kinase inhibitor has been approved for use in the treatment of CLL. This drug has shown beneficial effects including a higher overall response rate, sustained remissions, and a tolerable toxicity level. In this meta-analysis, we aimed to compare the adverse drug events which were associated with the use of ibrutinib for the treatment of patients with CLL. Methods: A careful search was carried out through the Cochrane Central, EMBASE, MEDLINE (PubMed), and through www.ClinicalTrials.com. The following criteria for inclusion were considered: Both randomized trials and observational cohorts; Studies comparing the adverse drug events observed with the use of ibrutinib versus a control group for the treatment of CLL. The RevMan software (version 5.3) was used to carry out this analysis and the analyzed data were represented by risk ratios (RR) and 95% confidence intervals (CI). Results: A total number of 2456 participants with CLL were included in this analysis. One thousand one hundred thirteen participants were treated with ibrutinib whereas the remaining 1343 participants were assigned to the control (non-ibrutinib) group. Results of this current analysis showed Ibrutinib not to be associated with significantly higher risk of anemia (RR: 0.90, 95% CI: 0.671.21; P=.49), thrombocytopenia (RR: 0.61, 95% CI: 0.32-1.14; P=.12), neutropenia (RR: 0.50, 95% CI: 0.25-1.00; P=.05), and febrile neutropenia (RR: 0.89, 95% CI: 0.32-2.49; P=.83) in these patients with CLL. The risk for respiratory tract infection was also similarly manifested (RR: 1.01, 95% CI: 0.78-1.30; P=.96). However, ibrutinib was associated with a high risk of abdominal manifestations in comparison to the control group (RR: 1.62, 95% CI: 1.32-2.00; P=.00001). The risk for diarrhea was also significantly higher in the Ibrutinib group (RR: 2.14, 95% CI: 1.44-3.17; P=.0002). Conclusions: During the treatment of CLL, ibrutinib was not associated with significantly higher risks of anemia, thrombocytopenia, or neutropenia compared to the control group. However, abdominal manifestations were significantly higher with ibrutinib. Advanced phase trials should further confirm this hypothesis.