Real-world experience and long-term outcomes of a mandatory non-medical switch of adalimumab originator to biosimilars in inflammatory bowel disease

Background: Over the last decade, the treatment options for inflammatory bowel disease (IBD) have significantly progressed with the emergence of new medications designed to target various immune pathways and mitigate inflammation. Adalimumab (ADA) is a tumor necrosis factor alpha antagonist and stands as an effective treatment for IBD. In April 2021, the province of British Columbia implemented a mandatory non-medical switch policy of the ADA originator Humira^® to ADA biosimilars. Biosimilars offer a potential cost-effective, safe, and efficacious alternative to the originator, yet there remains limited real-world evidence on long-term outcomes of ADA non-medical switching in IBD.

Aim: To assess the long-term outcomes of non-medical switching from the ADA originator Humira^® to an ADA biosimilar among IBD patients.

Methods: A retrospective observational chart review study was conducted on IBD patients eligible for the provincially mandated non-medical switch to an ADA biosimilar. The primary outcome was treatment persistence at 30 months post-switch. Secondary outcomes included the proportion of and reasons for therapy alteration or ADA discontinuation, loss of response (LOR) rates, adverse events (AE), and clinical and biochemical remission status. Patients who remained on the originator throughout the switch period, through compassionate support or private pay, constituted the comparison group.

Results: Patients in the originator (n = 43) and biosimilar switch (n = 228) groups displayed similar demographics and baseline disease characteristics. By the study endpoint of 30 months, there was no difference in the rate of treatment persistence in either group (n = 36, 83.7% originator group vs n = 201, 88.2% biosimilar group, P = 0.451). Treatment persistence demonstrated similar rates of discontinuation between both study groups (log-rank P = 0.543). There was a numerical but not statistically significant difference in rates of adverse outcomes between either group (39.5% originator vs 28.9% biosimilars, P = 0.206). This included comparable rates of LOR (27.9% vs 17.5%) or AE (11.6% vs 11.4%) between the originator and biosimilar cohorts, respectively. C-reactive protein and fecal calprotectin levels were similar one year pre- and post-switch.

Conclusion: These data support the long-term efficacy and safety of non-medical ADA switching in IBD and will help inform patients and physicians in jurisdictions currently undergoing biosimilar switching.