Update on the medical treatment of juvenile idiopathic arthritis

Methotrexate in juvenile idiopathic arthritis: advice and recommendations from the MARAJIA expert consensus meeting

BACKGROUND

Conventional pharmacological therapies for the treatment of juvenile idiopathic arthritis (JIA) consist of non-biological, disease-modifying antirheumatic drugs, among which methotrexate (MTX) is the most commonly prescribed. However, there is a lack of consensus-based clinical and therapeutic recommendations for the use of MTX in the management of patients with JIA. Therefore, the Methotrexate Advice and RecommendAtions on Juvenile Idiopathic Arthritis (MARAJIA) Expert Meeting was convened to develop evidence-based recommendations for the use of MTX in the treatment of JIA.

METHODS

The preliminary executive committee identified a total of 9 key clinical issues according to the population, intervention, comparator, outcome (PICO) approach, and performed an evidence-based, systematic, literature review. During the subsequent Expert Meeting, the relevant evidence was assessed and graded, and 10 recommendations were made.

RESULTS

Recommendations relating to the efficacy, optimal dosing and route of administration and duration of treatment with MTX in JIA, and to the issue of folic acid supplementation to prevent MTX side effects, use of MTX in the treatment of chronic JIA-associated uveitis, combination treatment with biologic agents, and the use of vaccinations in patients with JIA were developed. The selected topics were considered to represent clinically important issues facing clinicians caring for patients with JIA. Evidence was insufficient to formulate recommendations for the use of biomarkers predictive of treatment response.

CONCLUSIONS

These consensus recommendations provide balanced and evidence-based recommendations designed to have broad value for physicians and healthcare clinicians involved in the clinical management of patients with JIA.

Management of Juvenile Idiopathic Arthritis: A Clinical Guide

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease of childhood. The outcome in patients with JIA has markedly improved with the advent of biologic drugs. Although early aggressive therapy with biologics seems to be very effective, this approach leads to overtreatment in patients who would respond to classic disease-modifying anti-rheumatic drugs. Therefore, methotrexate remains first-line long-term therapy for most children with polyarticular JIA. Tumor necrosis factor-α inhibitors have shown tremendous benefit in children with refractory non-systemic JIA. Similar effects have been observed with interleukin-1 and interleukin-6 blockade in patients with systemic JIA. Correct choice and timely use of available medications to achieve early and sustained remission with as few side effects as possible remain challenges for the treating physician. In this review, a practical, clinically oriented guide to the management of JIA is provided, focusing on pharmacological treatment with non-steroidal anti-inflammatory drugs, intra-articular and systemic corticosteroids, disease-modifying anti-rheumatic drugs, and biologic agents. In addition, issues regarding treatment failure, early aggressive treatment, and drug tapering are discussed, with alternative treatment options being suggested.

Pediatric Rheumatology for the Primary Care Clinicians-Recognizing Patterns of Disease

This review presents a diagnostic approach to musculoskeletal and rheumatic diseases in children for primary care clinicians. The focus is on juvenile idiopathic arthritis (JIA) as the major arthritis disease in children. It is necessary to know the personalities of these JIA categories. It is also crucial to be able to recognize the common infectious, orthopedic and mechanical, malignant, genetic, other rheumatic diseases, and other miscellaneous syndromes that can mimic JIA. To do so requires recognition of clinical patterns using a thorough musculoskeletal and rheumatic history and repeated complete physical exams with emphasis on the musculoskeletal exam. It also requires targeted and limited laboratory testing with careful follow-up over time.

Methotrexate for maintaining remission in paediatric Crohn's patients with prior failure or intolerance to thiopurines: a multicenter cohort study

BACKGROUND AND AIMS

Methotrexate [MTX] is an immunomodulating drug that can be used to maintain remission in patients with Crohn's disease [CD], but data on efficacy and tolerability in children and teenagers are scarce. We evaluated the long-term efficacy and tolerability of MTX monotherapy after thiopurine therapy in paediatric CD patients.

METHODS

A multicenter cohort of paediatric MTX users who stopped thiopurines due to ineffectiveness or intolerance between 2002 and 2012 were included and followed for at least 12 months. Relapse-free use was defined as steroid and biologics-free clinical remission after the introduction of MTX, and included intentional discontinuation of successful therapy before the end of the observation period.

RESULTS

A total of 113 patients with CD in remission were followed while on MTX monotherapy, of whom 75 [66%] had failed on thiopurines and 38 [34%] had stopped thiopurines due to side effects. Median age at the introduction of MTX was 14 years [range 7 to 17], and 93% used the subcutaneous route. Kaplan-Meier analysis showed that 52% of the study cohort were still in steroid- and biologics-free remission after 12 months of MTX monotherapy, with a difference that did not reach significance between thiopurine-intolerant and thiopurine-failing patients [p = 0.21, log-rank test].

CONCLUSIONS

The findings of this cohort study suggest that MTX is an effective immunomodulator to maintain remission after stopping thiopurines. MTX maintenance should be considered before stepping up to anti-tumor necrosis factor alpha therapy. MTX is probably somewhat more effective in patients who stopped thiopurines due to side effects than in those who failed on thiopurines.

Abatacept in difficult-to-treat juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in children and an important cause of short-term and long-term disability. Gene changes in the immune system can predispose to JIA and regulation of the immune system is crucial in the pathogenesis. The goal of therapy is complete disease control using disease-modifying antirheumatic drugs (DMARDS). Activated T-cells may play a role in the immunopathology of JIA. Therefore, targeting T-cell activation is a rational approach for the treatment of JIA. Abatacept (ABA), a selective co-stimulation modulator, has been shown to be effective in treating all JIA subtypes and is generally safe and well tolerated in JIA. Neutralizing antibodies were found in 6/9 (67%) of seropositive patients, but anti-ABA antibodies did not appear to be associated with disease flare, serious adverse events, acute infusional adverse events, hypersensitivity, autoimmune disorders, or low ABA serum concentrations. Anti-ABA antibodies were more frequent when ABA concentrations were below therapeutic levels. Although information on ABA in JIA is still limited, available data suggest a potential role in difficult to treat JIA patients previously treated with other biologic agents and for non-responders to TNF-blockade.

Selectively weakened binding of methotrexate by human dihydrofolate reductase allows rapid ex vivo selection of mammalian cells

Ex vivo selection of transduced hematopoietic stem cells (HSC) with drug-resistance genes offers the possibility to enrich transduced cells prior to engraftment, toward increased reconstitution in transplant recipients. We evaluated the potential of highly methotrexate (MTX)-resistant variants of human dihydrofolate reductase (hDHFR) for this application. Two subsets of hDHFR variants with reduced affinity for MTX that had been previously identified in a bacterial system were considered: those with substitutions at positions 31, 34, and/or 35, and those with substitutions at position 115. The variants were characterized for their resistance to pemetrexed (PMTX), an antifolate that is related to MTX. We observed a strong correlation between decreased binding to both antifolates, although the identity of specific sequence variations modulated the correlation. We chose a subset of hDHFR variants for tests of ex vivo MTX resistance, taking into consideration their residual specific activity and their decrease in affinity for the related antifolates. Murine myeloid progenitors and other differentiated hematopoietic cells were transduced and exposed to MTX in a nucleotide-free medium. Bone marrow (BM) cells including 15% cells infected with F31R/Q35E were enriched to 98% transduced cells within 6 days of ex vivo selection. hDHFR variant F31R/Q35E allowed a strong ex vivo enrichment upon a short exposure to MTX relative to a less resistant variant of hDHFR, L22Y. We have thus demonstrated that bacterial selection of highly antifolate-resistant hDHFR variants can provide selectable markers for rapid ex vivo enrichment of hematopoietic cells.

Biologics in children's autoimmune disorders: efficacy and safety

Advances in understanding the pathogenesis of rheumatic diseases have led to the discovery of mechanisms of inflammation and autoimmunity and have made possible the invention of new target-specific drugs. Biologic drugs, designed to inhibit specific components of the immune system, such as cytokines, cytokine gene expression, and their complex interactions, have revolutionized the treatment options in pediatric rheumatology. Only three agents are currently available for treating juvenile idiopathic arthritis (JIA): etanercept, at the dose of 0.8 mg/kg once weekly, adalimumab at the dose of 24 mg/m(2) every 2 weeks, and abatacept at the dose of 10 mg/kg at weeks 0, 2, 4, and then every 4 weeks. They are well tolerated and relatively safe in children: Side effects are generally mild and include injection site reactions and infections. Infliximab, rilonacept, and canakinumab are also approved by the Food and Drug Administration for treatment of pediatric autoimmune disorders and are currently investigated in JIA. This review summarizes the current state of biologic drugs, their clinical application, and their efficacy and safety in the pediatric age.

Mutational 'hot-spots' in mammalian, bacterial and protozoal dihydrofolate reductases associated with antifolate resistance: sequence and structural comparison

Human dihydrofolate reductase (DHFR) is a primary target for antifolate drugs in cancer treatment, while DHFRs from Plasmodium falciparum, Plasmodium vivax and various bacterial species are primary targets in the treatment of malaria and bacterial infections. Mutations in each of these DHFRs can result in resistance towards clinically relevant antifolates. We review the structural and functional impact of active-site mutations with respect to enzyme activity and antifolate resistance of DHFRs from mammals, protozoa and bacteria. The high structural homology between DHFRs results in a number of cross-species, active-site 'hot-spots' for broad-based antifolate resistance. In addition, we identify mutations that confer species-specific resistance, or antifolate-specific resistance. This comparative review of antifolate binding in diverse species provides new insights into the relationship between antifolate design and the development of mutational resistance. It also presents avenues for designing antifolate-resistant mammalian DHFRs as chemoprotective agents.

Pediatric rheumatology for the adult rheumatologist

Although many manifestations of rheumatic diseases in children are similar to those in adults, there exist important differences. These include variations in presentation and complications, differential diagnoses to consider, medication side effects, impact on growth, and psychosocial issues. As there is a US and worldwide shortage of pediatric rheumatologists, many children with rheumatic illnesses are cared for by other physicians, especially by adult rheumatologists. This article is aimed toward educating the adult rheumatologist in 4 key areas of childhood rheumatic disease: juvenile idiopathic arthritis, other rheumatic and inflammatory illnesses seen primarily in the pediatric population, differences in rheumatic diseases common to both adults and children, and psychosocial issues.

Biological therapies for the treatment of juvenile idiopathic arthritis: Lessons from the adult and pediatric experiences

Biologics have advanced the therapy of adult and pediatric arthritis. They have been linked to rare serious adverse outcomes, but the actual risk of these events is controversial in adults, and largely unknown in pediatrics. Because of the paucity of safety and efficacy data in children, pediatric rheumatologists often rely on the adult literature. Herein, we reviewed the adult and pediatric literature on five classes of medicines: Tumor necrosis factor (TNF) inhibitors, anakinra, rituximab, abatacept, and tocilizumab. For efficacy, we reviewed randomized controlled studies in adults, but did include lesser qualities of evidence for pediatrics. For safety, we utilized prospective and retrospective studies, rarely including reports from other inflammatory conditions. The review included studies on rheumatoid arthritis and spondyloarthritis, as well as juvenile idiopathic arthritis. Overall, we found that the TNF inhibitors have generally been found safe and effective in adult and pediatric use, although risks of infections and other adverse events are discussed. Anakinra, rituximab, abatacept, and tocilizumab have also shown positive results in adult trials, but there is minimal pediatric data published with the exception of small studies involving the subgroup of children with systemic onset juvenile idiopathic arthritis, in whom anakinra and tocilizumab may be effective therapies.

Oral disease-modifying treatments for multiple sclerosis: the story so far

Multiple sclerosis (MS) represents the prototypic inflammatory autoimmune disorder of the CNS. It is the most common cause of neurological disability in young adults and exhibits considerable clinical, radiological and pathological heterogeneity. Increased understanding of the immunopathological processes underlying this disease, advances in biotechnology and the development of powerful magnetic resonance imaging (MRI) technologies, together with improvements in clinical trial design, have led to a variety of valuable therapeutic approaches to MS. Therapy for MS has changed dramatically over the past decade, yielding significant progress in the treatment of relapsing remitting and secondary progressive forms; however, most of the clinically relevant therapeutic approaches are not yet available as oral formulations. A substantial number of preliminary and pivotal reports have provided promising results for oral therapies, and various phase III clinical trials are currently being initiated or are already underway evaluating the efficacy of a variety of orally administered agents, including cladribine, teriflunomide, laquinimod, fingolimod and fumaric acid. It is hoped that these trials will advance the development of oral therapies for MS.