Infliximab and Adalimumab in the Treatment of Fistulizing Crohn's Disease: A Propensity Score-Matched Analysis From the Prospective Persistence Australian National IBD Cohort (PANIC4) Study.

INTRODUCTION

There are spare data on comparative medication efficacy in fistulizing Crohn's disease (FCD), particularly with immunomodulator cotherapy. Persistence is a unique way to assess real-world outcomes.

METHODS

The persistence of all dispensed biological agents was analyzed from the Australian Pharmaceutical Benefits Scheme registry data 2005-2021 for FCD. Propensity score matching was performed to account for baseline cohort imbalance.

RESULTS

There were 5,739 lines of therapy in 4,466 patients over the 16-year period with 17,144 patient-years of follow-up; through therapy, 2,605 of 5,739 (45.4%) used adalimumab, and 3,134 of 5,739 (54.6%) used infliximab; 1,697 of 5,739 (29.6%) used thiopurine cotherapy at induction, while 242 of 5,739 (4.2%) used methotrexate. As a first-line biologic (biologic-naive), infliximab showed superior overall and corticosteroid-free persistence to adalimumab ( P = 0.0002 and P = 0.0021, respectively). Used after first-line (biologic-exposed), there was no difference between agents for overall persistence ( P = 0.064), although infliximab showed greater corticosteroid-free persistence ( P = 0.030). Coinduction with thiopurine was associated with improved overall and corticosteroid-free persistence ( P = 0.0002 and P = 0.045, respectively). After propensity score matching, infliximab showed superior overall and corticosteroid-free persistence compared with adalimumab in bio-naive ( P < 0.0001 and P = 0.0016, respectively), not in bio-exposed patients ( P = 0.12 and P = 0.074, respectively). Thiopurine was associated with superior overall and corticosteroid-free persistence use, although no difference was seen with methotrexate.

DISCUSSION: The Persistence Australia National IBD Cohort with real-world data of nonhierarchical prescribing of biological agents supports the superiority of infliximab over adalimumab in bio-naive patients with FCD, but did not show a therapeutic difference in bio-exposed FCD. Thiopurine cotherapy was independently associated with improved biological agent persistence in FCD.