(035) Safety Events in Patients with Polyarticular-Course Juvenile Idiopathic Arthritis Exposed to Tofacitinib (Xeljanz) or Biologics: Real-World Data from the CARRA Registry

Background: Polyarticular-course juvenile idiopathic arthritis (pcJIA) is a clinically heterogeneous group of arthritides that often requires chronic treatment with advanced therapies, such as biologics. Tofacitinib (Xeljanz®) was approved by the U.S. FDA in 2020 as the first non-biologic targeted synthetic drug to treat pediatric patients ages ≥2 years with pcJIA. Long-term follow-up studies in patients with pcJIA are needed to further understand the benefit/risk profile of tofacitinib. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry prospectively collects detailed clinical data, including medication use and safety events, about patients with pediatric-onset rheumatic diseases (including pcJIA) in the US and Canada.

Objectives: To describe baseline characteristics of pcJIA patients treated with tofacitinib and biologics in the real-world and estimate incidence rates of safety events, including, but not limited to, thrombosis, serious infections, malignancies, and major adverse cardiovascular events.

Methods: Patients with pcJIA enrolled in the CARRA Registry and aged 2-17 years when newly initiating treatment with a unique biologic or tofacitinib on or after 20 September 2020 were included. Data were collected at Registry sites every 6 months from standard-of-care clinical encounters. Safety events are reported as exposure-adjusted incidence rates (IR) as events per 100 person-years with 95% confidence intervals (CI) for the tofacitinib and biologics cohorts.

Results: As of January 9, 2024, 720 biologic exposure episodes in 636 patients and 159 patients treated with tofacitinib have been identified for inclusion. Mean age of the tofacitinib and biologics cohort was 12.9 and 10.8 years, respectively. Similar proportions of patients had rheumatoid factor positive polyarthritis (15.7% and 14.3%). Median disease duration at medication initiation was longer in the tofacitinib than the biologics cohort (5 versus 2 years). More patients in the tofacitinib cohort had previous biologic use compared to the biologic cohort (88.7% versus 54.9%). No safety events have been observed in the tofacitinib cohort in 148 person-years of observation to date. 6 episodes of serious infection (IR: 0.862, 95% CI (0.387-1.918)) and 4 events of fracture (IR: 0.575, 95% CI (0.139-1.336)) have been observed in the biologics cohort in 696 person-years of observation to date.

Conclusions: No safety events have been identified to date for tofacitinib-exposed pcJIA patients identified from the CARRA Registry, consistent with the known safety profile for tofacitinib. Continued follow-up with the Registry will be conducted to characterize the long-term safety profile of tofacitinib.