VA Study: Patients Switching to Biosimilar Infliximab More Likely to Stop Treatment

A study of patients served by the US Veterans Healthcare Administration found that those who switched from the infliximab reference product, Remicade, to an infliximab biosimilar were almost 3 times more likely to stop treatment and 5 times more likely to switch to another innovator biologic.

In fact, 91% of the patients who stopped the biosimilar switched back to Remicade, the study found. However, “reasons for discontinuation and switching are unknown,” investigators wrote in the study, which appeared in Current Medical Research and Opinion.

Physician and patient resistance to switching from an innovator or reference product to a biosimilar—or from one biosimilar to another—constitutes one of the major barriers to biosimilar adoption, despite the cost savings that can be achieved. Resistance can occur even if there is evidence that switching is safe; for example, a well-known 2018 study involving switching to infliximab biosimilars among patients with inflammatory bowel disease (IBD) showed no increase in disease activity.

A provider survey released this week by Cardinal Health showed that rheumatologists were only half as likely as oncologists to switch a patient to a biosimilar if they were doing well on a reference product.

For this new study, investigators used Veterans Healthcare Administration data from January 2012 through December 2019 to identify adults with rheumatoid arthritis (RA), psoriatic arthritis (PsA), plaque psoriasis (PsO), ankylosing spondylitis (AS), or Crohn disease and ulcerative colitis (IBD) who were treated with Remicade or an infliximab biosimilar. Patients were required to have at least 5 treatments with Remicade in the 12 months prior to the index date to be evaluated.

Patients who had at least 12 months of observation time prior to the first treatment with Remicade were considered the primary population, and their data were assessed from the start of treatment with a biosimilar. Discontinuation was defined as switching to another biologic—including back to Remicade—or having more than 120 days between consecutive treatments.

Results showed a median duration of follow-up of 796 days among those who switched to a biosimilar (N = 838) and a median duration of follow-up of 337 days among those who continued the reference infliximab (N = 849). Those who switched products were 2.88 times more likely to stop taking the therapy and 4.99 times more likely to switch to a different innovator product (both P < .001).

Of the 653 patients who switched off the biosimilar to another innovator biologic, 594 switched back to the reference infliximab, Remicade. Results were similar among those with long-term and shorter-term Remicade use before the switch, and similar between those with RA and IBD.

Reference

Lin I, Melsheimer R, Bhak RH, et al. Impact of switching to infliximab biosimilars on treatment patterns among US veterans receiving innovator infliximab. Curr Med Res Opin. Published online February 7, 2022. https://doi.org/10.1080/03007995.2022.2037846