Background Clinical remission is today the treatment goal for Rheumatoid Arthritis (RA), which requires fast and assertive therapeutic decisions for a tight control of disease activity. Few objective parameters are available to guide clinical decisions, namely in switcher patients. We designed a preliminary algorithm introducing immunogenicity assessment in the current approach to RA patients receiving biotechnologic therapies.
Objectives To evaluate the concordance between the new algorithm and current clinical practice, comparing the effectiveness of “immunogenicity-based” versus “empirical-based” switches in a cohort of patients with established RA receiving biologics. Methods: EULAR therapeutic response was evaluated in 105 RA patients (naive or switchers) over one year, through GEE analysis. Serum drug trough levels were assessed by ELISA and anti-drug antibodies (ADAb) by Bridging ELISA. Results
During follow-up, 48.6% of patients (Group A) had concordant therapeutic decisions. One year after the therapeutic decision, patients from Group A had a higher probability of achieving response (OR = 7.91, p <0.001, 95% CI = 3.27–19.13) and low disease activity (OR = 9.77, p <0.001, 95% CI = 4.69–20.37). Non-responders to a TNFi in the presence of detectable serum drug trough levels and no detectable ADAb had higher probability of achieving response by switching to a drug with different MOA, rather than another TNFi, even after adjusting for potential confounders, such as DAS28 at the time of switch (OR = 6.76, p = 0.004, 95% CI = 1.82–25.04).
Conclusions Immunogenicity assessment might help to optimise therapeutic decisions, leading to a better control of disease activity with significant better clinical outcomes in RA patients receiving biotechnologic therapies.