Hypersensitivity reactions to biologics in chronic rheumatic diseases: prevalence and associated factors.

Background: The aim of our study was to determine the prevalence of hypersensitivity reactions in patients with chronic rheumatic diseases (CRD) treated with biologic therapies, and to evaluate the associated factors.

Research design and methods: A 6-year retrospective, single-center study was performed, including patients with CRD treated with biologic therapies.

Results: A total of 151 patients (109 women and 42 men) with a mean age of 53.2 ± 13.6 years were included. They were followed for rheumatoid arthritis (59.6%), spondyloarthritis (31.8%), juvenile idiopathic arthritis (6%), rhupus syndrome and scleroderma (1.3% each). Anti-TNF alpha agents were the most frequently prescribed biologic class (67.5%). However, anti-CD20 (Rituximab) was the most frequently prescribed molecule (23.2%). Hypersensitivity reactions occurred in 16.6% (n = 25), mainly systemic (72%) and immediate (84%). The positivity of the rheumatoid factor (p = 0.01), and the axial phenotype of spondyloarthritis (p = 0.01) were significantly associated with the occurrence of hypersensitivity reactions. Infliximab was the biologic agent most associated with hypersensitivity reactions (p = 0.002). Etanercept was most frequently associated with local hypersensitivity reactions (p = 0.04). Concomitant Methotrexate use significantly decreased the risk of hypersensitivity reactions (p = 0.01).

Conclusions: Considering the predictive factors of hypersensitivity reactions to biologics in clinical practice could help anticipate risks and improve patient safety.