The first biosimilar approved for spondyloarthritis, Inflectra, is a biosimilar version of the TNF inhibitor infliximab (Remicade) and was approved in April of 2016 for ankylosing spondylitis and psoriatic arthritis.
A study of 250 spondyloarthritis and rheumatoid arthritis patients and 77 control patients, published at the European League Against Rheumatism (EULAR) annual conference held earlier this month, suggests that switching to a biosimilar is not suitable for patients who have developed antibodies to the reference product that biosimilar is based on. In particular:
“Findings of the study, which has been peer-reviewed and was not funded by a pharma company, suggest that antibody-positive patients treated with [infliximab] should not be switched to treatment with the biosimilar [Inflectra], since the antibodies will interact with the new drug and potentially lead to loss of response.
Using assays to assess concentrations of anti-infliximab antibodies, 50.4% of [infliximab-treated] patients tested positive for anti-infliximab antibodies, and 100% of those who tested positive for anti-infliximab antibodies also exhibited antibody reactivity against the biosimilar.
Results are aligned with previous antibody data among patients with inflammatory bowel disease being treated with infliximab. Further studies are planned with biosimilar-treated patients to better assess the potentially different immune responses associated with biologics.”
The study’s lead author, Dr. Daniel Nagore concluded that, “The presence of these anti-infliximab antibodies is likely to enhance clearance of the drug from the body, potentially leading to a loss of response, as well as increasing the risk of side effects. Therefore, in patients where biological infliximab is ineffective due to the presence of circulating antibodies, switching to its biosimilar will lead to the same problems.”