Oral or Parenteral Methotrexate for treatment of Non- Systemic Juvenile Idiopathic Arthritis

Abstract

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. <br /> 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. <br /> 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. <br /> 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. <br /> There were more patients reaching PedACR90 (p=0.0004) and JADAS remission (p=0.019) in the sc cohort after 6 months of MTX treatment in the observed population analysis. Whereas, there was no statistical significance in the kinetic of reaching the response to MTX by Kaplan-Meyer analysis in reaching PedACR 30,50,70 and 90 and JADAS10 acceptable disease activity, minimal disease activity and remission between both cohorts. Results of adverse events analysis showed more side effects with parenteral MTX compared to oral MTX. These results could be related to the sc MTX or to the high disease activity for those patients who were started on sc MTX. <br /> In conclusion, result of our retrospective study showed some favor of sc Methotrexate in term of efficacy but not safety. Probably due to higher blood levels reached with injected Methotrexate typical side effects such as nausea, vomiting, and elevated transaminases were significantly more frequent upon sc than upon oral application. Such side effects markedly limit the continuation of treatment and must therefore been seen as an important disadvantage.