Background Methotrexate is approved and recommend as first line disease modifying antirheumatic drug (DMARD) in polyarticular juvenile idiopathic arthritis (JIA). In can be used orally or via s.c. injection.
Objectives S.c MTX is thought to be more efficious or act more rapidly than oral MTX. Thus we want to analyse the kinetic of response in JIA patients treated with oral versus s.c. MTX.
Methods In the German BIKER registry a cohort of biologics naïve JIA patients starting treatment with MTX was built. The data bank was screened for patients treated with MTX orally vs. s.c for the first time. The JIA-ACR 90 and the JADAS10 definition of remission were used as outcome parameters.
Results 410 JIA patients received treatment with oral MTX and 384 received s.c. MTX. RF negative polyarthritis was the most common JIA category (50%/51%) followed by by extended oligoarthritis (27%/26%), polyarticular psoriatic arthritis (18%/16%) and RF positive polyarthritis (5%/8%). Disease duration (2.3+/-3.0 vs 1.9+/-2.7 was statistically higher in the oral cohort (p=0.04) but age at onset and baseline were similar. The baseline disease activity was higher in the s.c. cohort (JADAS10 16.5+/-7.2 compared to 14.7+/-8.2; p<0.001 and active joint count 9.0+/-10.1 vs. 7.4+/-7.7; p=0,011). The weekly MTX dosages were comparable with 13.6+/-5.4mg and 13.3+/-4.5 mg. Concomitant treatment with NSAIDS (95%/89%), oral steroids (24%/25%) or intraarticular steroids (6%/8%) were comparable.
After 12 months of treatment, 150 (38.3%) reached a JIA ACR90 with oral MTX and 131 (35%) with s.c MTX while 86 (21. 8%) and 72 (19.5%) reached JADAS-remission (JADAS10≤1). By Kaplan-Meyer- analysis no difference in the early kinetic of response was found. Upon total observation for up to 7.5 years in the intention to treat population (patients discontinuing MTX due to inefficacy or intolerance or starting a biologic were calculated as non-responders) more patients in the oral cohort reached a JADAS-remission (162; 41%) than with s.c MTX (126; 34%) which was stastically borderline significant (p=0,05; odd's ratio 1.2 [95CI 1.0–1.8]).
Conclusions Data from the BIKER registry out of the clinical practice do show a high rate of JIA patients reaching a significant JIA-ACR response as well as JADAS-remission upon MTX as a sole DMARD. However, on the long term more patients with oral MTX reached JADAS remission. By Kaplan Meyer analyses we did not observe a superiority of s.c. MTX in the kinetic of response. The limitations of our analysis lie the character of a registry study, the lack of randomisation and study protocol leaving all decisions to start or to stop MTX by the responsible rheumatologist. Thus such data are preliminary and should be confirmed by randomized studies.
Disclosure of Interest None declared