(S) TNF-Alpha Inhibitors Biosimilar Use in France: A 207,118 Patients Longitudinal Study

Publication Number: 309

Background: TNF-alpha inhibitors have revolutionized the therapeutic care in chronic inflammatory diseases, but these medicines came to market at high prices. Several biosimilars were commercialized at patent expiry of the originator product, substantially decreasing the cost of treatment.

Objectives: To assess the biosimilar penetration rate in TNF-alpha inhibitors newly initiating patients and prevalent users from the date of first biosimilar commercialization, overall and according to the pathology treated, the physician specialty and patient characteristics.

Methods: Using data of the French National Health Data System (SNDS), infliximab, etanercept and adalimumab adult new users and adult prevalent users from the date of commercialization in France of the first biosimilar of these respective molecules (i.e. January 2015, May 2016 and October 2018) were included in the study. Patients were followed until September 30, 2021 in a longitudinal approach. Patient socio-demographic characteristics, underlying pathologies and switch pathways were analyzed descriptively.

Results: 207,118 patients were included in the study. Respectively 25,950, 27,727, 48,768 infliximab, etanercept and adalimumab initiating patients were included. Biosimilars represented 78%, 46% and 53% of the overall initiations of the three molecules, and 94%, 66% and 60% during the last year of follow-up. Respectively 20,254, 31,038, 53,381 of originator infliximab, etanercept and adalimumab prevalent users were included in the study. A total of 46%, 19% and 17% had switched at least once for a biosimilar at the end of the study. Biosimilar penetration rate was much higher for infliximab than for its counterparts. Biosimilar initiation and originator-to-biosimilar switch tended to be observed more in rheumatology than in the other specialties. Biosimilar use was consistent across patient characteristics such as age, sex, deprivation and medical history.

Conclusions: Biosimilar initiation rate increased rapidly from their market arrival and originator-to-biosimilar switch rate remained moderate, highlighting the need and usefulness of political action and biosimilar use tracking. Overall, biosimilar use depended mostly of the considered molecule (infliximab hospital delivery boosting biosimilar utilization) and of the specialty of the prescriber (with a faster biosimilar adoption by rheumatologists relatively to gastro-enterologists and dermatologists).