• anti-TNF
• DMARDs (biologic)
• disease activity
• outcomes research

Thank you for the interest1 in our recent publication, in which we explored treatment outcomes following a Danish mandatory switch from originator to biosimilar etanercept (SB4, 50 mg) in routine care.2 We showed that of the 2061 patients who were receiving originator etanercept and thus were eligible for the switch, as many as four of five (79%) switched to the biosimilar, despite the continued availability of the originator drug (as 25 mg pen or 50 mg powder solution). Among the patients who switched, we observed high retention rates of the biosimilar. The 6-month retention rate after switch (88%) was very similar to results of a recent Dutch study (90%), which reported outcomes of a non-mandatory switch following a specifically designed communication strategy.3 Furthermore, we found that the disease activity and flare rates 3 months prior to versus 3 months after the switch were similar at the level of the individual patients. Thus, we agree with Scherlinger and Schaeverbeke that biosimilars hold the potential to provide sustainable healthcare in inflammatory rheumatic diseases at reduced costs.1

The question raised by Scherlinger et al is whether the outcome of a shared patient-physician decision (=non-mandatory) is more favourable than a mandatory switch. In previous studies that explored non-mandatory switching, the shared patient-physician decision-making included training of personnel and use of specific questionnaires or communication techniques.3 4 For the Danish mandatory switch, no extra resources were allocated to conduct the switch procedure and no specific education of the healthcare personnel was provided. Furthermore, it was beyond the scope of our study to explore the practical aspects of the switch procedure including communication strategy with the patients. However, we have previously demonstrated that a mandatory switch from originator to biosimilar infliximab did not lead to a detectable increase in the use of healthcare resources.5

To determine whether shared patient-physician decision is superior to a mandatory switch in terms of lower nocebo effect, increased treatment efficacy and reduced healthcare costs, large-scale studies which are designed to explore these specific aspects are necessary—and highly needed. Such studies must also include evaluation of the extra healthcare resources allocated to and arising from the strategies investigated.

In conclusion, our paper adds important evidence to the use of biosimilars in routine care—however, some pieces are still missing in the puzzle.