Approximately Half of Patients Continued Treatment with Adalimumab Biosimilar ABP 501 at 1 Year

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Patients who were naïve to adalimumab tended to switch to other targeted therapies, while those who had been previously treated with adalimumab were more likely to switch back to the reference product.

Among a cohort of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS), about half of patients receiving the adalimumab biosimilar ABP 501 remained on treatment at the end of month 12, according to a study published in Rheumatology and Therapy.1

Patients previously prescribed to the adalimumab reference product were more likely to switch back to the bio-originator as opposed to another targeted treatment, regardless of indication and country of origin, which may be indicative of a possible nocebo effect.

ABP 501 is the first adalimumab biosimilar approved by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) for the treatment of immune-mediated inflammatory diseases, such as RA, PsA, and AS, and has been available in Europe since 2018.2

“Biosimilarity of ABP 501 to its reference product in terms of efficacy, safety, and immunogenicity has been demonstrated in 2 randomized controlled, double-blind, comparative clinical trials in patients with RA and patients with plaque psoriasis, respectively,” wrote Ran Jin, MD, PhD, observational research senior manager at Amgen, and colleagues. “However, due to the strict inclusion criteria, relatively short duration, and small sample sizes of randomized clinical trials, the results of these trials may not be generalizable to routine clinical practice. There remains a paucity of real-world data about biosimilar use, especially in indications such as PsA and AS, where clinical trial data were not available, and approval was granted on the basis of extrapolation.”

The retrospective study evaluated the treatment patterns of ABP 501 using real-world data from the IQVIA German and French pharmacy claims Longitudinal Prescription Data (LRx) databases.

Patients with RA, AS, or PsA who initiated the biosimilar between October 2018 and March 2020 were included in the analysis and observed for ≥ 365 days pre- and post-ABP 501 initiation. The persistence rates and treatment switch after biosimilar discontinuation were collected for each disease cohort and patients were categorized as either naïve or experienced to adalimumab.

The median persistence of the biosimilar was 9.4 (95% confidence interval [CI]: 8.6 – 10.3), 10.2 (95% CI: 9.0 – 11.7), and 12.1 (95% CI: 11.0 – 13.1) months in German patients with RA, PsA, and AS, respectively. The median persistence was 11.7 (95% CI: 9.9 – 13.3), 7.1 (95% CI: 5.8 – 8.4), and 10.8 (95% CI: 9.6 – 11.9) months in the French cohort for the same conditions. In the German cohort, the persistence rates were 44% in the RA group, 47% in the PsA group, and 51% in the AS group. In French patients, persistence rates were 50% for patients with RA, 32% for patients with PsA, and 46% for patients with AS.

In patients who switched from the biosimilar to another targeted therapy during the first 12 months post-initiation, switching patterns varied among those who were adalimumab-naïve and those who were experienced. Patients who were naïve to adalimumab were more likely to switch to other targeted therapies, such as non-adalimumab tumor necrosis factor inhibitors (TNFs), non-TNF biologics, or Janus kinase inhibitors (JAKs). Those who had been previously treated with adalimumab were more likely to switch back to the adalimumab reference product.

Investigators noted limitations including a potential misclassification of disease types as diagnoses were assumed based on patient treatment history and electronic medical records. Additionally, the IQVIA LRx claims database did not contain information on medications prescribed in a hospital setting or baseline clinical characteristics.

“Future studies are needed to understand reasons for switching in the real-world setting upon adalimumab biosimilars entering the US market starting in January 2023,” investigators concluded.


  1. Jin R, Kruppert S, Scholz F, et al. Treatment Persistence and Switching Patterns of Adalimumab Biosimilar ABP 501 in European Patients with Rheumatologic Diseases. Rheumatol Ther. Published online March 4, 2024. doi:10.1007/s40744-024-00647-4
  2. Markus R, McBride HJ, Ramchandani M, Chow V, Liu J, Mytych D, et al. A review of the totality of evidence supporting the development of the first adalimumab biosimilar ABP 501. Adv Ther. 2019;36(8):1833–50.