Biologic Disease-modifying Antirheumatic Drug (bDMARD)-induced Neutropenia: A Registry from a Retrospective Cohort of Patients with Rheumatic Diseases Treated with 3 Classes of Intravenous bDMARD

Objective. To examine the rate, risks factors, and consequences of neutropenia induced by intravenous (IV) biologic disease-modifying antirheumatic drugs (bDMARD). Methods. We conducted a retrospective cohort study in 499 patients with rheumatic diseases treated by IV abatacept (ABA), infliximab (IFX), or tocilizumab (TCZ). Results. Rheumatoid arthritis (RA) was the most frequent diagnosis (72%). Fifty-two patients (10.4%) experienced at least 1 episode of neutropenia. No episodes of grade 4 neutropenia were documented. TCZ was more frequently related to neutropenia than ABA or IFX (18.6% vs 3.8% and 2.8%, respectively, p < 0.001). The following factors were identified as predictors of experiencing neutropenia with IV bDMARD: history of neutropenia with methotrexate (MTX; synthetic DMARD; OR 1.56, 95% CI 1.17-7.14), concomitant treatment by MTX (OR 1.21, 95% CI 1.01-2.64), and TCZ treatment (OR 2.72, 95% CI 1.53-9.05). Patients experiencing a TCZ-induced neutropenia did not show a higher risk of severe infections; however, this group had a shorter drug survival (9 mos vs 20 mos, p < 0.02) compared with TCZ patients without neutropenia. Conclusion. Among 3 different classes of IV bDMARD, TCZ is associated with the higher risk of neutropenia. No increased frequency of infection episodes was documented in this group.