Tofacitinib and Risk of Malignancy: Results From the Safety of Tofacitinib in Routine Care Patients With Rheumatoid Arthritis (STAR‐RA) Study

Results of the ORAL Surveillance safety trial have indicated that there is an increased risk for the development of malignancies with tofacitinib therapy when compared to treatment with tumor necrosis factor inhibitors (TNFi). This study was undertaken to further examine this safety concern in rheumatoid arthritis (RA) patients in a real-world setting.Using US insurance claims data from Optum Clinformatics (2012-2020), IBM MarketScan Research Databases (2012-2018), and Medicare (parts A, B, and D, 2012-2017), we created 2 cohorts of RA patients who had initiated treatment with tofacitinib or TNFi. The first cohort, designated the real-world evidence (RWE) cohort, included RA patients from routine care. For the second cohort, designated the randomized controlled trial (RCT)-duplicate cohort, we emulated the inclusion and exclusion criteria that were applied in the ORAL Surveillance trial of tofacitinib, which allowed us to assess the comparability of our results with the results of that trial. Cox proportional hazards models with propensity score fine-stratification weighting were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the risk of any malignancy (excluding nonmelanoma skin cancer). Database-specific estimates were meta-analyzed using fixed-effects models with inverse-variance weighting.The RWE cohort consisted of 83,295 patients, including 10,504 patients (12.6%) who received treatment with tofacitinib. The pooled weighted HR for the primary outcome of any malignancy associated with tofacitinib treatment compared to any malignancy associated with TNFi therapy was 1.01 (95% CI 0.83, 1.22) in the RWE cohort and 1.17 (95% CI 0.85, 1.62) in the RCT-duplicate cohort (compared to the ORAL Surveillance trial HR of 1.48 [95% CI 1.04, 2.09]).We did not find evidence of an increased risk of malignancy development with tofacitinib therapy, in comparison with TNFi therapy, in RA patients treated in a real-world setting. However, our results cannot rule out the possibility of an increase in risk that may accrue with a longer duration of treatment with tofacitinib.