Microfibrillar-associated protein 4 as a predictive biomarker of treatment response in patients with chronic inflammatory diseases initiating biologics: secondary analyses based on the prospective BELIEVE cohort study

BACKGROUND: Currently, there are no reliable biomarkers for predicting treatment response in chronic inflammatory diseases (CIDs).

OBJECTIVE: To determine whether serum microfibrillar-associated protein 4 (MFAP4) levels can predict the treatment response to biological therapy in patients with CIDs.

METHODS: The BELIEVE study was originally designed as a prospective, multi-center cohort study of 233 patients with either rheumatoid arthritis, psoriatic arthritis, psoriasis, axial spondyloarthritis, Crohn's disease, or ulcerative colitis, initiating treatment with a biologic agent (or switching to another). Clinical assessment and blood sample collection were performed at baseline and 14-16 weeks after treatment initiation. The primary analyses included participants with available blood samples at baseline; missing data were handled as non-responders. The patients were stratified into the upper tertile of serum MFAP4 (High MFAP4) versus a combined category of middle and lower tertiles (Other MFAP4). The primary outcome was the proportion of patients with clinical response to biologic therapy after 14-16 weeks.

RESULTS: 211 patients were included in the primary analysis population. The mean age was 43.7 (SD: 14.8) years, and 120 (59%) were female. Positive treatment response was observed in 41 (59%) and 69 (49%) for High MFAP4 and Other MFAP4, respectively. When adjusting for pre-specified variables (CID, age, sex, smoking status, and BMI), the adjusted OR was 2.28 (95% CI: 1.07 to 4.85) for a positive treatment outcome in the High MFAP4 group.

CONCLUSION: A high MFAP4 status before initiating biological treatment is associated with a positive clinical response, when adjusting for confounding factors.