Safety and Efficacy of Adalimumab Biosimilar in Psoriasis and Hidradenitis Suppurativa:

Objectives: To evaluate the clinical experience, safety, and effectiveness of adalimumab biosimilars in patients with psoriasis and hidradenitis suppurativa. Methods: We conducted a retrospective, single-center observational study between March and September 2024 using electronic medical records from King Abdulaziz Medical City and King Abdullah Specialized Children's Hospital, Riyadh, Saudi Arabia. Pediatric and adult patients with psoriasis or hidradenitis suppurativa who switched to adalimumab biosimilars between 2016 and 2022 were included. Variables included demographics, disease characteristics, prior therapies, biosimilar use, and adverse events. Results: A total of 57 (93% adults; 50.9% female) patients were included. Obesity was present in 35.1%, and 6 (10.5%) patients had hidradenitis suppurativa. Plaque psoriasis was the most common subtype (72.5%), with psoriatic arthritis in 35.3%. Most patients (89.5%) switched to a biosimilar after treatment with the originator. The median dose and duration were 40 mg and 2-3 years, with high adherence (hidradenitis suppurativa 83.3%; psoriasis 90.2%). All patients with hidradenitis suppurativa improved, whereas 68.6% of patients with psoriasis responded, 19.6% showed no improvement, and 11.8% worsened. Adverse events were infrequent. Patients without obesity and those with prior response to adalimumab were more likely to benefit. Conclusion: Adalimumab biosimilars demonstrate favorable efficacy and safety, particularly in prior responders. Patients with hidradenitis suppurativa showed consistent improvement. The low rate of adverse events and absence of new safety signals support safe clinical use. Further multicenter studies are needed to confirm these findings.