Uptake of rheumatology biosimilars in the absence of forced switching

To describe the uptake and system-level effects of the introduction of biosimilars in a setting without forced switching.

We used data from the Swedish Rheumatology Quality register from start of marketing of infliximab (Remsima® and Inflectra®) and etanercept (Benepali®) biosimilars until 31 December 2016. We compared users of each originator-product and its biosimilar(s) by line of treatment: bDMARD-naïve patients, non-medical switchers (vs. matched patients remaining on originator), and patients switching from a previous bDMARD of another type.

From the start of marketing 1343 patients started an infliximab biosimilar (22 months) and 2691 started etanercept (9 months). Overall, the introduction of these biosimilars resulted in an increase of the total number of ongoing infliximab and etanercept treatments (originator + biosimilar) . At the end of the study period, biosimilars accounted for 31% of all infliximab treatments and 31% of all etanercept-treated patients. For each line of therapy, we noted only small differences in patient characteristics between those starting the originator product vs. its biosimilar(s).

Introduction of biosimilars have effects beyond replacement of the originator product, in terms of an increased rate of bDMARD initiation. Selection to non-medical switching displayed no particular disease- or patient-characteristics.