Effectiveness of Adalimumab Biosimilars and Originator for Psoriasis.

Importance: The uncertainties about the real-world effectiveness of adalimumab biosimilars limit their widespread adoption for psoriasis.

Objective: To compare the effectiveness of adalimumab biosimilars Amjevita and Imraldi with Humira for psoriasis.

Design, Setting, And Participants: An emulation of 2 targeted pragmatic clinical trials was conducted using data from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR), a prospective pharmacovigilance registry tracking individuals receiving biologic and conventional systemic treatments for psoriasis in the UK and the Republic of Ireland. Data from patients with psoriasis using adalimumab registered to BADBIR were included. Data were collected from September 2007 to January 2023, and data were analyzed from January to September 2023.

Exposures: The effectiveness of initiating Amjevita and Imraldi were compared with initiating Humira among adalimumab-naive patients, and the effectiveness of switching from Humira to either Amjevita or Imraldi were compared with continuing Humira among patients who had been using Humira consistently for more than 2 years.

Main Outcomes And Measures: The study outcomes were absolute Psoriasis Area and Severity Index (PASI) score of 2 or less and PASI score of 4 or less at 12 months after the index date. Inverse propensity treatment weighting was used to analyze receiving either biosimilars or Humira to account for confounding. Multiple imputations were used to account for missing PASI data at 12 months and inverse probability of censoring weighting to account for censorship due to deviation from the treatments under investigation. Logistic regression models were fitted to compare the outcomes between study cohorts.

Results: Of 11 400 included patients, 6924 (60.7%) were male, and the mean (SD) age was 45.3 (12.5) years. A total of 6133 patients were identified in the new user analysis (5416 starting Humira, 382 starting Amjevita, and 335 starting Imraldi) and 5267 patients in the switcher analysis (3808 continuing Humira, 847 switching to Amjevita, and 612 switching to Imraldi). Amjevita and Imraldi new users had no significantly different probability of achieving a PASI score of 2 or less (Amjevita: adjusted odds ratio [aOR], 0.98; 95% CI, 0.78-1.25; Imraldi: aOR, 0.83; 95% CI, 0.64-1.07) and a PASI score of 4 or less (Amjevita: aOR, 1.07; 95% CI, 0.84-1.37; Imraldi: aOR, 0.91; 95% CI, 0.69-1.20) compared with Humira new users. Patients who switched to Amjevita and Imraldi also had no statistically significant differences in achieving a PASI score of 2 or less (Amjevita: aOR, 1.19; 95% CI, 0.94-1.51; Imraldi: aOR, 0.92; 95% CI, 0.72-1.18) and a PASI score of 4 or less (Amjevita: aOR, 1.32; 95% CI, 0.96-1.84; Imraldi: aOR, 1.00; 95% CI, 0.70-1.41) compared with those who continued Humira.

Conclusions And Relevance: In this study, Amjevita and Imraldi were as effective as Humira for both new starters and patients switching to biosimilars from Humira.