Precision medicine: something is changing in rheumatology Translated title: Medicina de precisión, algo está cambiando en la reumatología

Recent insights in rheumatoid arthritis (RA) necessitated updating the European League Against Rheumatism (EULAR) RA management recommendations. A large international Task Force based decisions on evidence from 3 systematic literature reviews, developing 4 overarching principles and 12 recommendations (vs 3 and 14, respectively, in 2013). The recommendations address conventional synthetic (cs) disease-modifying antirheumatic drugs (DMARDs) (methotrexate (MTX), leflunomide, sulfasalazine); glucocorticoids (GC); biological (b) DMARDs (tumour necrosis factor (TNF)-inhibitors (adalimumab, certolizumab pegol, etanercept, golimumab, infliximab), abatacept, rituximab, tocilizumab, clazakizumab, sarilumab and sirukumab and biosimilar (bs) DMARDs) and targeted synthetic (ts) DMARDs (Janus kinase (Jak) inhibitors tofacitinib, baricitinib). Monotherapy, combination therapy, treatment strategies (treat-to-target) and the targets of sustained clinical remission (as defined by the American College of Rheumatology-(ACR)-EULAR Boolean or index criteria) or low disease activity are discussed. Cost aspects were taken into consideration. As first strategy, the Task Force recommends MTX (rapid escalation to 25 mg/week) plus short-term GC, aiming at >50% improvement within 3 and target attainment within 6 months. If this fails stratification is recommended. Without unfavourable prognostic markers, switching to-or adding-another csDMARDs (plus short-term GC) is suggested. In the presence of unfavourable prognostic markers (autoantibodies, high disease activity, early erosions, failure of 2 csDMARDs), any bDMARD (current practice) or Jak-inhibitor should be added to the csDMARD. If this fails, any other bDMARD or tsDMARD is recommended. If a patient is in sustained remission, bDMARDs can be tapered. For each recommendation, levels of evidence and Task Force agreement are provided, both mostly very high. These recommendations intend informing rheumatologists, patients, national rheumatology societies, hospital officials, social security agencies and regulators about EULAR's most recent consensus on the management of RA, aimed at attaining best outcomes with current therapies.

Following a greater understanding of the pathogenesis of rheumatoid arthritis (RA), the treatment of this chronic disease has improved with the availability of biological agents targeting key molecules. Despite this, initial treatment produces an inadequate response in many patients and guidance on the optimal treatment for these patients is needed. Research in specific patient populations aims to define predictive biomarkers of response to identify those patients most likely to benefit from treatment with specific agents. Although there have been conflicting results from studies of various genetic markers, single nucleotide polymorphisms in the tumour necrosis factor (TNF) -308 promoter region may play a role in response to specific TNF inhibitors. Microarray analysis of mRNA expression levels has identified unique sets of genes with differentially regulated expression in responders compared with non-responders to the TNF inhibitor infliximab. Of the various protein biomarkers studied, rheumatoid factor and/or anticitrullinated protein autoantibodies may have a future role in predicting response or guiding the order in which to use biological agents. Further research is needed with larger, well-designed studies to clarify the current understanding on the role of biomarkers in predicting treatment response in RA to help guide clinical decision-making. Individualised treatment has the potential to improve the therapeutic outcomes for patients.