Does switching to a biosimilar maintain disease control in stable ankylosing spondylitis?
For people with stable ankylosing spondylitis (AS), switching from a reference biologic drug to a biosimilar is a common practice to reduce costs while maintaining disease control. Biosimilars are highly similar, lower-cost versions of biologic medications. The key question is whether making the switch risks losing the symptom control you have achieved. Current evidence strongly supports that switching is safe and effective for most patients with stable AS.
What the research says
A 2026 systematic review of randomized controlled trials and real-world studies found that switching stable AS patients from reference infliximab to its biosimilar maintained efficacy and had comparable safety profiles 47. Retention rates (how long patients stay on the drug) and disease activity outcomes were similar between biosimilars and reference products when baseline patient characteristics were considered 47. Multinational registry data from diverse healthcare systems corroborate these findings 47. Immunogenicity profiles (the body's immune response to the drug) also showed equivalence between products 47. Additionally, a 2026 study on switching to a low-volume adalimumab biosimilar (AVT02) across multiple indications, including AS, reported that patients maintained disease control with improved injection site pain and high adherence 8. These results align with the broader understanding that approved biosimilars achieve molecular and therapeutic equivalence to their reference biologics through rigorous analytical and clinical testing 47.
What to ask your doctor
- Is my current disease activity stable enough to consider a biosimilar switch?
- Which biosimilar options are approved for ankylosing spondylitis, and what does the evidence show about switching?
- How will my disease activity be monitored after switching to a biosimilar?
- What should I do if I notice any change in symptoms after the switch?
- Are there any differences in injection site reactions or other side effects between my current biologic and the biosimilar?
This question is drawn from common patient questions about Rheumatology and answered using cited medical research. We do not provide individualized advice.