Clinical efficacy and nocebo effect following non-medical biosimilar switch in patients with inflammatory bowel...

We aimed to evaluate clinical efficacy, biomarker activity, therapeutic drug monitoring (TDM), adverse events (AEs), and nocebo effect in inflammatory bowel disease (IBD) patients who underwent non-medical biosimilar switching.

A prospective observational study of consecutive IBD patients who underwent biosimilar switch. Disease activity, biomarkers, TDM, and AEs, including the nocebo effect were captured 8 weeks before switch, at the time of switch (baseline),12 and 24 weeks after the switch.

210 patients were included [81.4% had Crohn's disease (CD), the median age at inclusion: 42 years (IQR 29-61)]. There was no significant difference in the rates of clinical remission at week 8 before switch, baseline, week12, and 24 after switch: 89.0%,93.4%,86.3%,and 90.8%,p = 0.129. The biomarker remission rates were not significantly different; CRP:81.3%,74.7%,81.2%,73.0%,p = 0.343; fecal calprotectin: 78.3%,74.5%,71.7%,76.3%,p = 0.829. The rates of maintaining therapeutic levels (84.7%,83.9%,83.0%,85.3%,p = 0.597) and prevalence of positive anti-drug antibodies remained unchanged. Drug persistence at 12 week of switch was 97.1%, regardless of disease phenotype and originator. The nocebo effect was observed in 13.3%. The discontinuation rate was 4.8%.

Despite a significant number of early nocebo complaints within the first 6 months after the biosimilar switch, no significant changes were found in clinical efficacy, biomarkers, therapeutic drug level, or anti-drug antibodies.