Background

The lack of evidence under routine clinical settings limited the widespread adoption of adalimumab biosimilars for psoriasis treatment.

Objective

This study compared the drug survival and safety of adalimumab biosimilars to Humira for psoriasis treatment.

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 (HR) were calculated using Cox proportional hazard models. Meta-analyses using random effect models were performed to combine results from 3 databases.

Results

7387 biosimilar new users and 3654 switchers were matched and compared with Humira users. No differences in all-cause discontinuation were found between biosimilars and Humira new users (HR: 0.99, 95% CI: 0.94–1.04). Switching from Humira to biosimilars was associated with a higher discontinuation rate compared to 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).

Conclusion

Adalimumab biosimilars can be considered viable alternatives to Humira for new patients with comparable effectiveness and safety. However, due to the higher likelihood of discontinuation, patients who switch from Humira to biosimilars may require closer monitoring and support.