The potential role of vitamin K-dependent protein S (PROS) in predicting response to the methotrexate/etanercept combination in RA

Vitamin K-dependent protein S (PROS) can function as a prospective biomarker in predicting response to the methotrexate (MTX)/etanercept (ETA) combination in patients with rheumatoid arthritis (RA), according to a study published in Arthritis Research & Therapy.

The study included 65 RA patients belonging to the French multicentric, longitudinal, and prospective ESPOIR cohort. Thirty-two patients were treated with MTX/ETA out of which 24 and 8 patients were responders and non-responders while MTX/ /adalimumab (ADA) was administered in 33 patients and the numbers of responders and non-responders were 27 and 5, respectively.

A significantly high serum level of PROS was noted in MTX/ ETA combination responders (p = 0.08) while, no difference was seen for MTX/ADA. ROC curve depicted 40 μg/ml as the best concentration threshold for PROS to differentiate responders from non-responders in both groups. PROS demonstrated effective theranostic performances for the ETA/MTX combination. The pooled data analysis based on ESPOIR and SATRAPE studies showed that the etanercept and methotrexate combination had a statistically significantly higher theranostic value (P= 0.009).

Olivier Vittecoq and co-researchers have corroborated the ability of PROS as a combination of markers efficient in predicting the response for MTX/ETA combination in patients with RA not responding to MTX. Moreover, it may help in accurate prediction of bDMARDs responses and in choosing effective treatments in RA patients.

Reference: Vittecoq O, Guillou C, Hardouin J, Gerard B, Berenbaum F, Constantin A, Rincheval N, Combe B, Lequerre T, Cosette P. Validation in the ESPOIR cohort of vitamin K-dependent protein S (PROS) as a potential biomarker capable of predicting response to the methotrexate/etanercept combination. Arthritis Res Ther. 2022 Mar 21;24(1):72.