Does Serum Calprotectin Hold Predictive Value for Clinical Response to Anti-TNF Agents?

While anti—tumor necrosis factor (anti-TNF) agents have revolutionized the treatment of rheumatoid arthritis (RA), not all patients will achieve a good clinical response after 6 months of treatment. Furthermore, while some responders can taper their doses of these agents, not all patients are able to so.

In an effort to accurately predict an individual patient’s response after starting or tapering an anti-TNF agent, researchers from the Netherlands, reporting findings in Rheumatic and Musculoskeletal Diseases, explain that calprotectin has some predictive value for clinical response in patients starting anti-TNF treatment, although it was not predictive of clinical response after tapering.

The researchers obtained baseline serum samples and clinical outcomes of patients with RA who initiated treatment with adalimumab or etanercept by using the Biologic Individual Optimised Treatment Outcome Prediction study, a prospective longitudinal prediction study of patients with RA 18 years or older. Additional data were collected from patients in the dose tapering arm of the Dose Reduction Strategies of Subcutaneous TNF Inhibitors study, which investigated noninferiority of dose reduction in patients stable on adalimumab or etanercept.

Baseline and 6-month serum samples were available for 50 patients initiating adalimumab and 75 patients initiating etanercept. Additionally, 102 patients randomized to taper their dose of adalimumab (n = 38) or etanercept (n = 64) had baseline serum samples available.

In the prospective study, calprotectin levels were weakly to moderately significantly correlated with a disease activity score counted in 28 joints with C-reactive protein (DAS28-CRP), (R = .32; P <.001), erythrocyte sedimentation rate (R = .41; P <.001), and CRP (R = .57; P <.001) at baseline. In the tapering study, calprotectin levels were significantly correlated with CRP (R = .21; P = .03) only.

At 6 months, 50 (40%) of the patients who initiated treatment achieved a good response, measured by European League Against Rheumatism criteria, and baseline calprotectin levels were higher in responders, at 985 ng/mL (range, 558 ng/mL to 1417 ng/mL), than in nonresponders, at 645 ng/mL (range, 415 ng/mL to 973 ng/mL).

Among those who tapered, 47 patients (46%) successfully reduced their dose, 19 (19%) successfully discontinued anti-TNF treatment, and 36 (35%) were unsuccessful at tapering. Calprotectin levels at baseline were similar among all 3 groups.

According to the authors, serum calprotectin has some value for predicting clinical response to anti-TNF agents, although it does not have added value to other clinical factors already used, and it is not a useful predictor for clinical response after tapering therapy.

Reference

Tweehuysen L, den Broeder N, van Herwaarden N. Predictive value of serum calprotectin (S100A8/A9) for clinical response after starting or tapering anti-TNF treatment in patients with rheumatoid arthritis. RMD Open. 2018;4(1):e000654.