Comparison of treatment of severe rheumatoid arthritis patients with biological agents and JAK-STAT inhibitors. An observational study.

Introduction: Treatment of severe rheumatoid arthritis (RA) is currently based either on biological agents or Janus kinase/signal transducer and activator of transcription inhibitors, most often in combination with methotrexate (MTX).

Aim of the study: The aim of the study was to compare the effectiveness and side effects of bio- logic disease-modifying antirheumatic drugs (bDMARDs) and targeted synthetic (ts) DMARDs treatment.

Material and methods: The analysis included 108 RA patients with active disease treated with MTX 25 mg per week. Eighty patients (group I) were treated with bDMARDs and 28 patients (group II) with JAK-STAT inhibitors. The duration of morning stiffness, pain on Visual Analogue Scale (VAS), 28-joints Disease Activity Score (DAS28) and Simplified Disease Activity Score (SDAI) were assessed. Classical radiographic images of patients' hands and feet using the Larsen and Dale's criteria were evaluated. The effects of treatment with bDMARDs and tsDMARDs were analyzed.

Results: All studied patients presented at least Larsen and Dale's stage 3 of X-ray changes typical for RA. There were no statistically significant differences in disease duration, ESR, CRP, DAS28 and SDAI values between studied groups. Patients from group II previously used higher numbers of bDMARDs than group I treated with bDMARDs. Low disease activity after treatment was achieved by all patients; therefore patients from group II (treated with tsDMARDs) achieved lower values of patients' global assessment on VAS.

Conclusions: The results of the present observational study indicated that treatment with JAK inhibitors is very promising. These drugs are not inferior in effectiveness to bDMARDs. It is important to monitor patients for thromboembolic events before and during JAK treatment.