Real‐world outcomes of switching from adalimumab originator to adalimumab biosimilar in patients with inflammatory bowel disease: The ADA‐SWITCH study

Data on the outcomes after switching from adalimumab (ADA) originator to ADA biosimilar are limited. The aim was to compare the treatment persistence, clinical efficacy, and safety outcomes in inflammatory bowel disease patients who maintained ADA originator vs. those who switched to ADA biosimilar.Patients receiving ADA originator who were in clinical remission at standard dose of ADA originator were included. Patients who maintained ADA originator formed the non-switch cohort (NSC), and those who switched to different ADA biosimilars constituted the switch cohort (SC). Clinical remission was defined as a Harvey-Bradshaw index ≤4 in Crohn's disease and a partial Mayo score ≤2 in ulcerative colitis. To control possible confounding effects on treatment discontinuation, an inverse probability treatment weighted proportional hazard Cox regression was performed.Five hundred and twenty-four patients were included: 211 in the SC and 313 in the NSC. The median follow-up was 13 months in the SC and 24 months in the NSC (p < 0.001). The incidence rate of ADA discontinuation was 8% and 7% per patient-year in the SC and in the NSC, respectively (p > 0.05). In the multivariate analysis, switching from ADA originator to ADA biosimilar was not associated with therapy discontinuation. The incidence rate of relapse was 8% per patient-year in the SC and 6% per patient-year in the NSC (p > 0.05). Six percent of the patients had adverse events in the SC vs. 5% in the NSC (p > 0.05).Switching to ADA biosimilar did not impair patients' outcomes in comparison with maintaining on the originator.