Background: Subcutaneous methotrexate (sMTX) administration is considered more effective than the oral route due to better bioavailability and a lower rate of adverse drug reactions (ADRs); however, clinical data supporting this hypothesis is scarce.
Objectives: The aim of the study was to evaluate the efficacy and tolerability of sMTX in patients with active rheumatoid arthritis (RA), including a subset classified as an early stage of RA.
Material and methods: A post-marketing, multicenter, open-label, non-randomized, non-interventional study enrolled 771 adult patients with active RA treated with sMTX (Metex®) for 2-6 weeks. The evaluation of therapy effectiveness (DAS28-ESR or DAS28-CRP) and monitoring of ADRs was an element of routine patient management. Therapy effectiveness was scored as the achievement of remission or response (according to European League Against Rheumatism (EULAR)).
Results: Among 761 (98.7%) patients that continued sMTX (after 25-31 weeks), clinical response was achieved by 69.5%, remission by 19.2% and low disease activity by 34.2%. Patients aged >60 years were less likely to achieve both remission (odds ratio (OR) = 0.61 (95% confidence interval (95% CI) = 0.39-0.93)) and clinical response (OR = 0.82 (95% CI = 0.71-0.95)), while overweight/obese patients (OR = 1.11 (95% CI = 1.00-1.24)) and those with early RA had greater chance to reach a clinical response (OR = 1.18 (95% CI = 1.03-1.34)). There were 16 ADRs (no serious or severe). In addition, at least 2-fold increase in alanine transaminase (ALT) activity was noted in 10 patients (1.3%).
Conclusions: After 6-month therapy with sMTX, about 70% of patients with RA achieve a clinical response, and remission was observed in 20%. Younger age, overweight/obesity and an early stage of the disease are factors increasing therapy effectiveness; sMTX is well tolerated.
Keywords: methotrexate; response rate; rheumatoid arthritis; subcutaneous; tolerance.