LAUSR

Background: Etanercept (Etn) is a biologic agent (BA) that has been proved to be successful in the treatment of rheumatic diseases, by acting as tumour necrosis factor inhibitor, but it is costly. In February 2016, the first etanercept biosimilar (EtnBS) was launched in Germany as a relatively cheaper alternative. Objectives: In a recent study using the German Longitudinal Prescriptions database IQVIA® (LRx) we showed that despite many patients (approximately 50%) were moved from EtnBA to EtnBS treatment over the year following its launch, some (10%) switched back to the original product after few months1. As new data are available from the database, the objective of this second analysis was to evaluate switching-back dynamics over longer follow-up durations. Methods: The German LRx covers prescription data from January 2008, representing approximately 60% of the German statutory health insurance market. The study period was from February 2016, date of EtnBS launch in Germany, to August 2017 (last available data). Patients receiving first EtnBS prescription (index date) during the study period were retrospectively identified and separated into two groups based on treatment received in the 12 months prior to index date: treatment-naïve patients (no prior biologic treatment) and patients previously treated with EtnBA or other anti-TNF biologics. For the latter group, the cumulative proportion of patients switching back from EtnBS to EtnBA and the median time to the switch-back were evaluated over 3 time periods corresponding to dates of new data availability within the data source: February 2016-September 2016 (1), February 2016-March 2017 (2), and February 2016-August 2017 (3). The results were compared using the chi square test with significance set at p<0.05. Data on the market share for biologic agents and their biosimilars in rheumatic diseases are also shown on a monthly basis, between January 2015 and August 2017. Results: A total of 707, 1,607 and 2,229 patients were identified who received prior EtnBA treatment before switching to EtnBS in time periods 1, 2 and 3 respectively. Of these patients, the proportion of those who switched back to EtnBA significantly (p<0.05) increased over time: 53 (7%) in time period 1, 153 (10%) in time period 2 and 320 (14%) in time period 3. Patients generally switched back to the biologic agent within 3–4 months of starting EtnBS treatment. The use of EtnBS by rheumatologists has constantly grown since February 2016, with a market share of 6% in Dec 2016 increased to 12% in August 2017. Conclusions: This study confirmed previous findings on switching dynamics between EtnBA and its biosimilar. In addition, the study shows that despite a constant increase in the use of EtnBS since its launch, from September 2016 to August 2017, the proportion of patients who switch back to EtnBA after 3–4 months of initiating EtnBS has doubled. Reference [1]Alten R, et al. ISPOR 20th Annual European Congress in Glasgow, Scotland2017November 4–8. Disclosure of Interest: R. Alten Grant/research support from: The study was sponsored by Pfizer, H. Jones Employee of: Pfizer, C. Curiale Employee of: Pfizer, T. Meng Employee of: Pfizer, L. Lucchese Grant/research support from: The study was sponsored by Pfizer, C. Miglio Grant/research support from: The study was sponsored by Pfizer