Post-Authorisation Active Safety Surveillance Program Among Patients Treated WithTofacitinib for Polyarticular Juvenile Idiopathic Arthritis (pJIA) and Juvenile Psoriatic Arthritis (PsA) Within the United Kingdom (UK) Juvenile Idiopathic Arthritis (JIA) Biologics Register

Study type

• Study type:
  Non-interventional study

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Name of medicine:
  Xeljanz

Population studied

• Age groups:
  Children (2 to < 12 years)

  Adolescents (12 to < 18 years)
• Estimated number of subjects:
  1

Study design details

• Main study objective:
  To estimate the post-approval incidence rate of the following outcomes of interest among patients with pJIA or juvenile PsA who initiate tofacitinib and patients with pJIA or juvenile PsA treated with approved bDMARDs: venous thromboembolism, serious infections and other important infections, all malignancies combined (excluding NMSC), lymphoma (examined separately), and lung cancer.
• Data analysis plan:
  Crude incidence rates (IRs) of events overall and stratified by baseline characteristics such as disease activity, subtype of JIA, treatment type defined as monotherapy or combination therapy with MTX on the index date, and prior JIA therapy in both tofacitinib cohort and comparator cohort will be calculated. A comparative analysis will examine the risk of the outcomes of interest among patients from the tofacitinib cohort compared to the patients from the comparator cohort adjusting for confounding by baseline characteristics. Propensity scores will be estimated using baseline characteristics described in the study protocol. Propensity score adjusted IR (per 100 PY) and associated 95% CI will be calculated for the outcomes of interest, for which there are adequate data using an exact Poisson method. Where there are adequate data to compare the risk between cohorts, multivariable Cox proportional hazards models will be fit to compare risk of the outcome of interest.