Tocilizumab-induced neutropenia in rheumatoid arthritis patients with previous history of neutropenia: case series and review of literature

One of the adverse events of tocilizumab (TCZ) is a transient, dose-dependent neutropenia. The recommendations of the Summary of Product Characteristics state that this neutropenia should be managed according to the absolute neutrophil count (ANC). However, the approach to a patient who had a history of neutropenia induced by previous DMARDs and developed TCZ-induced neutropenia remains unclear. We would like to report a series of four patients with rheumatoid arthritis who developed Grade 2 neutropenia (ANC 1–1.5 × 10⁹/L) following intravenous TCZ treatment at a dose of 8 mg/kg. All of them had a previous history of neutropenia (Grade 2 or Grade 3) due to Etanercept (three patients) and Sulfasalazine (one patient). Therefore, we decided to decrease the TCZ dosage by 10–20 % approximately. Reducing of the dosage did not have any influence on the efficacy of TCZ, and all of our patients remained in clinical remission. The mechanisms underlying neutropenia induced by Tocilizumab, Etanercept and Sulfasalazine are also discussed in this article.