Switching patients with inflammatory arthritis from Etanercept (Enbrel®) to the biosimilar drug, SB4 (Benepali®): A single-centre retrospective observational study in the UK and a review of the literature.

Abstract

Objective/Aim:SB4 (Benepali®), the Etanercept biosimilar, is licenced in the UK for the same indications as the reference product, Enbrel®. In 2016, the Rheumatology Department at Blackpool Teaching Hospitals switched the Etanercept patients, who gave consent, to SB4. A proportion of these patients switched back to Etanercept and therefore we aimed to investigate the reasons of SB4 withdrawal and compare our results with the current evidence.Methods:We included all the patients switched to SB4 until April 2018, identified from the departmental biologics database. We also searched the published and grey literature through November 2018 for similar articles.Results:72 Etanercept patients switched to SB4, of which 19 (26.4%) switched back to Etanercept within 6 months on the biosimilar product. All the 19 patients remained on Etanercept until the time of data analysis. The main reason of withdrawal was loss of effect (LOE, 58%). In RA, the duration on Etanercept was associated with SB4 withdrawal (OR 1.43 [95% CI 1.02, 2.00]) and LOE was reflected in the DAS- 28, PGS and CRP increase and in the number of tender joints (all p <0.05). We found ten observational studies reporting 3184 patients, who switched from Etanercept to SB4 and 432 of them (14%) stopped SB4.Conclusion:The majority (73.6%) stayed on SB4, which is consistent with the current evidence. Taking also into consideration the results of the other studies, it is unclear if this withdrawal is a true failure on SB4, nocebo effect or spontaneous disease flare.