Switching to Biosimilar SB4 Tolerated By Most Patients, European Study Finds

Samsung Bioepis’ etanercept biosimilar, SB4, was effective and well-tolerated in the majority of patients who switched from originator etanercept (Enrel), according to a study from Poland.

The biosimilar is approved in a variety of European markets under the name Benepali. While it was approved by the FDA in April 2019, it has not yet launched here due to patent litigation. The anti-tumor necrosis factor (anti-TNF) inhibitor is currently prescribed in the United States for rheumatoid arthritis (RA), juvenile idiopathic arthritis, psoriatic arthritis (PsA), ankylosing spondylitis, and plaque psoriasis.

The observational study looked at patients being treated for RA, juvenile idiopathic arthritis, PsA, or ankylosing spondylitis, in which the originator etanercept replaced SB4.

Etanercept was replaced with SB4 in 162 patients (Group 1), and in another 6 patients SB4 was the initial biologic used (Group 2). Efficacy and safety were assessed over a 6-month period.

The biosimilar was effective and well-tolerated in the majority of patients. For 24 patients in Group 1 (14.8%), returning to Enbrel was necessary due to loss of efficacy or adverse events. Returning to the originator reversed the loss of efficacy or resolved the adverse event.

Previous observational studies have found rates of discontinuing the biosimilar ranging from 2% to 14%. In this study:

• 9 patients experienced clinically confirmed loss of efficacy
• 9 patients reported subjective loss of efficacy
• 13 patients reported adverse events, the most common of which were headache and skin lesions
• 4 patients had injection site reactions

No adverse events were reported in the 6 patients for whom the biosimilar was the initial therapy (Group 2), and the biosimilar was effective in these patients.

Other studies coming out of Europe have also found SB4 to work well for the majority of patients who switched from the originator etanercept.

The authors conclude that SB4 was effective and well-tolerated in most patients, but that further research is required to investigate the effects of switching patients between originators and biosimilars.

Reference

Felis-Giemza A, Chmurzyńska K, Nałęcz-Janik J, et al. Observational study of inflammatory arthritis treatment by etanercept originator switched to an etanercept biosimilar. Reumatologia. 2019;57(5):257—263. doi:10.5114/reum.2019.89516.