Evaluation of pediatric rheumatologists' approach to rituximab use: a questionnaire study

Rituximab (RTX) is a chimeric monoclonal antibody that targets the CD20 antigen on B cells and is used in various autoimmune disorders. In this study, we aimed to measure the awareness of pediatric rheumatologists about the use of RTX through a survey. Between February and March 2023, a 42-question survey was sent via email to pediatric rheumatology specialists in Turkey. The participants were questioned for which diagnoses and system involvement they preferred to use RTX, which routine tests they performed, vaccination policy, and adverse events that occurred during or after infusion. Forty-one pediatric rheumatologists answered the survey. They prescribed RTX most frequently for systemic lupus erythematosus (87.8%) and ANCA-associated vasculitis (9.8%). Prior to the administration of RTX, 95% of clinicians checked renal and liver function tests, as well as immunoglobulin levels. The most frequently tested hepatitis markers before treatment were HBsAg and anti-HBs antibody (97.6%), while 85.4% of rheumatologists checked for anti-HCV. Clinicians (31.4%) reported that they postpone RTX infusion 2 weeks following an inactivated vaccine. Sixty-one percent of rheumatologists reported starting RTX treatment 1 month after live vaccines, while 26.8% waited 6 months. The most frequent adverse events were an allergic reaction during RTX infusion (65.9%), hypogammaglobulinemia (46.3%), and rash (36.6%). In the event of hypogammaglobulinemia after RTX treatment, physicians reported that they frequently (58.5%) continued RTX after intravenous immunoglobulin administration.

RTX has become a common treatment option in pediatric rheumatology in recent years. Treatment management may vary between clinician such as vaccination and routine tests.

• During the course of rituximab therapy, clinicians should be attentive to specific considerations in pre-treatment, during administration, and in post-treatment patient monitoring.

• There are differences in practice among clinicians in the management of RTX therapy. These practice disparities have the potential to impact the optimal course of treatment. • This study highlights that standardized guidelines are needed for RTX treatment in pediatric rheumatology, particularly for vaccination policies and routine tests.