Drug Survival and Safety of Biosimilars Compared with Originator Adalimumab for Psoriasis: A Multinational Cohort Study

Abstract Background The lack of evidence from routine clinical settings has limited the widespread adoption of adalimumab biosimilars for the treatment of psoriasis. Objectives To compare the drug survival and safety of adalimumab biosimilars with Humira® in psoriasis. Methods We conducted a prevalent new-user cohort study using data from the French National Health Data System (SNDS), the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) and the Spanish Registry of Systemic Therapy in Psoriasis (BIOBADADERM). Adalimumab-naïve patients initiating adalimumab biosimilars (new users) were compared with Humira new users. Patients switching from Humira to biosimilars (switchers) were compared with those who continued Humira treatment. Patients were matched 1 : 1 based on previous adalimumab exposure time to create equal-sized cohorts of biosimilar and Humira users. Co-primary outcomes included drug discontinuation and serious adverse events (SAEs). Hazard ratios (HRs) were calculated using Cox proportional hazard models. Meta-analyses using random-effect models were performed to combine results from the three databases. Results In total, 7387 biosimilar new users and 3654 switchers were matched and compared with Humira users. No differences in all-cause discontinuation were found between biosimilar and Humira new users [HR 0.99, 95% confidence interval (CI) 0.94–1.04]. Switching from Humira to biosimilars was associated with a higher discontinuation rate than remaining on Humira (HR 1.35, 95% CI 1.19–1.52). Similar results were observed for discontinuation due to ineffectiveness or adverse events. Risks of SAEs were similar between biosimilar new users and Humira new users [incidence rate ratio (IRR) 0.91, 95% CI 0.80–1.05] or between switchers and continuous Humira users (IRR 0.92, 95% CI 0.83–1.01). Conclusions Adalimumab biosimilars can be considered viable alternatives to Humira for new patients, with comparable effectiveness and safety. However, owing to the higher likelihood of discontinuation, patients who switch from Humira to biosimilars may require closer monitoring and support.