In the Short Term, Most Patients With RA Remain on a Biosimilar Post Switch

Beginning in 2015, biosimilar products became available in the United Kingdom for the treatment of rheumatoid arthritis (RA), and the University of Manchester has been monitoring the long-term safety of these drugs in the BSRBR-RA study.

During this week’s European League Against Rheumatism (EULAR) Annual European Congress of Rheumatology, researchers from the University of Manchester reported on their findings regarding patients with RA involved in the BSRBR-RA study who had switched from reference infliximab or reference etanercept to biosimilar options of their respective therapies.

A total of 966 patients were included, and 760 of them had switched from brand-name etanercept to a biosimilar, while 206 of them had switched from brand-name infliximab to a biosimilar.

After a median follow-up of 22.5 months after the switch, the majority of patients remained on the biosimilar; 81% of the patients being treated with etanercept were continuing to receive a biosimilar, as were 81% of patients being treated with infliximab.

In total, 11% of the patients discontinued taking biologics completely, with most of those who discontinued doing so because of serious adverse events (including malignancy or infection). Six patients taking etanercept reported injection or infusion reactions after the switch, as did 3 patients taking infliximab. These reactions led 4 patients to switch back and 2 patients to discontinue.

Other reasons for discontinuation included remission, feeling generally unwell, ineffectiveness, or patient decision, among others. The time to switching back was 5 months (range, 3-8), and the time to discontinuation of all biologics was 7 months (range, 4-12).

The majority of patients, conclude the investigators, remain on a biosimilar in the short term after a switch, and hypersensitivity reactions are rare reasons to stop either drug completely or to switch back to the reference.

Reference

Davies R, Kearsley-Fleet L, Lunt M, et al. Frequency and reasons for switching back to biologic originator following initial switch to biologic biosimilar. Presented at: The European League Against Rheumatism European Congress of Rheumatology 2019; June 12-15, 2019; Madrid, Spain. Abstract SAT0141.