Aspects of early arthritis. Traditional DMARD therapy: is it sufficient?

Discovery of WD-890: A novel allosteric TYK2 inhibitor for the treatment of multiple autoimmune diseases

Tyrosine kinase 2 (TYK2) as a member of Janus kinase (JAK) family, mainly mediates the signaling of type I interferons (IFN), interleukin-12 (IL-12) and interleukin-23 (IL-23), which has become an attractive target for treatment of immune and inflammatory diseases. However, the development of selective TYK2 inhibitors is challenging due to the high homology of the catalytic kinase domain among the JAK family members. Here, we report a novel and potent allosteric inhibitor, WD-890, which binds to the pseudokinase domain of TYK2 with high selectivity and inhibits its function. We accomplished a series of preclinical studies to demonstrate the therapeutic efficacy of WD-890 in four animal models: systemic lupus erythematosus (SLE), psoriasis, psoriatic arthritis (PsA), and inflammatory bowel disease (IBD). The pharmacokinetic and toxicology results further indicate that WD-890 has favorable absorption, distribution, metabolism, and excretion (ADME) properties and tolerable toxicity. In conclusion, our study shows that WD-890 could be a promising oral TYK2 inhibitor for future treatment of autoimmune diseases.

Using Treg, Tr1, and Breg Expression Levels to Predict Clinical Responses to csDMARD Treatment in Drug-naive Patients With Rheumatoid Arthritis

BACKGROUND/AIM

Regulatory T cells (Treg) play a crucial role in maintaining immune tolerance and preventing autoimmune diseases. Recent data also indicate that type 1 regulatory T (Tr1) and regulatory B (Breg) cells play an inhibitory (i.e., protective) role in autoimmune diseases. Conventional synthetic disease-modifying antirheumatic drugs (csDMARD) are a first-line therapy for rheumatoid arthritis (RA), and our aim was to predict clinical responses of this treatment using immunophenotyping.

MATERIALS AND METHODS

We first detected the presence of immune cells in fresh blood from 16 healthy controls (HC) and 26 patients with RA (14 drug-naive and 12 csDMARD-experienced). Then, we recorded immunophenotypic changes in 14 drug-naive RA (naive RA) patients prior to csDMARD treatment (i.e., day 0) and after receiving treatment for 6 months. The observed changes were also compared with other clinical indicators, including the presence of anti-citrullinated peptide antibodies (anti-CCP), rheumatoid factor (RF) levels, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels.

RESULTS

Naive RA patients had significantly lower Tregs than HC and csDMARD-experienced patients (both p<0.0001) and the number of Tregs correlated with the diagnosis of RA and therapeutic efficacy of csDMARD treatment. Furthermore, lower baseline levels of Treg, memory Treg, Tr1, and higher PD-1+ Marginal B, Breg cells were significantly associated with decreased development of the 28-joint Disease Activity Score (DAS28) (all p<0.05), revealing better medical response. Multiple regression and principal component analysis identified Treg, Tr1, and Breg as potential predictors of csDMARD responses (Area under curve: 0.9; Accuracy: 92.86%). Furthermore, elevated Treg, Tr1, and Breg cells were associated with decreased DAS28, ESR, and CRP (all p<0.05); changes in Treg and Breg cell expression were also more pronounced among double negative anti-CCP and RF in RA patients with better outcomes (p<0.05).

CONCLUSION

Immunophenotyping can be an adjunct clinical tool to identify patients who are poor candidates for csDMARD therapy. Alternative therapeutic interventions in the early stages of disease should be formulated for these patients.

Discovery of a highly selective JAK3 inhibitor for the treatment of rheumatoid arthritis

Janus tyrosine kinase 3 (JAK3) is expressed in lymphoid cells and is involved in the signalling of T cell functions. The development of a selective JAK3 inhibitor has been shown to have a potential benefit in the treatment of autoimmune disorders. In this article, we developed the 4-aminopiperidine-based compound RB1, which was highly selective for JAK3 inhibition, with an IC₅₀ of value of 40 nM, but did not inhibit JAK1, JAK2 or tyrosine kinase 2 (TYK2) at concentrations up to 5 µM. Furthermore, RB1 also exhibited favourable selectivity against a panel of representative kinases. In a battery of cytokine-stimulated cell-based assays, this potent inhibitor of JAK3 activity with good selectivity against other kinases could potently inhibit JAK3 activity over the activity of JAK1 or JAK2 (over at least 100-fold). A combination of liquid chromatography-mass spectrometry (LC-MS) experiments validated that RB1 covalently modified the unique cysteine 909 residue in JAK3. In vivo, RB1 exerted significantly improved pathology in the joints of a collagen-induced arthritis mouse model. The reasonable pharmacokinetics properties (F = 72.52%, T1/2 = 14.6 h) and favourable results of toxicology experiments (LD₅₀ > 2 g/kg) suggest that RB1 has the potential to be an efficacious treatment for RA.

Discovery of the macrocycle (9E)-15-(2-(pyrrolidin-1-yl)ethoxy)-7,12,25-trioxa-19,21,24-triaza-tetracyclo[18.3.1.1(2,5).1(14,18)]hexacosa-1(24),2,4,9,14(26),15,17,20,22-nonaene (SB1578), a potent inhibitor of janus kinase 2/fms-like tyrosine kinase-3 (JAK2/FLT3) for the treatment of rheumatoid arthritis

Herein, we describe the synthesis and SAR of a series of small molecule macrocycles that selectively inhibit JAK2 kinase within the JAK family and FLT3 kinase. Following a multiparameter optimization of a key aryl ring of the previously described SB1518 (pacritinib), the highly soluble 14l was selected as the optimal compound. Oral efficacy in the murine collagen-induced arthritis (CIA) model for rheumatoid arthritis (RA) supported 14l as a potential treatment for autoimmune diseases and inflammatory disorders such as psoriasis and RA. Compound 14l (SB1578) was progressed into development and is currently undergoing phase 1 clinical trials in healthy volunteers.

Early treatment in early undifferentiated arthritis

The early diagnosis of new-onset rheumatoid arthritis (RA) has become a major objective for rheumatologists in order to identify a management strategy able to change the natural history of the disease and to prevent joint damage and functional impairment. Emergent evidence emphasizes the benefits of early aggressive therapy of RA. By the nineties, early arthritis cohorts have been collected throughout the world with the aim to increase the early referral of patients with early onset disease by the general practitioners and to collect data on the development of full-blown RA. The frequency of undifferentiated arthritis (UA) ranged from 23% to 81% in these early cohorts with most of them reporting a rate of 30%. The transition rate from UA to RA was between 13% and 54%. A percentage of 20-60% of patients with UA had a self-limiting disease. Our article deals with the controversy existing in the management of UA. Should every patient with UA be treated? Could patients with a favorable disease course be exposed to unnecessary risk with initiation of aggressive therapy with synthetic disease-modifying anti-rheumatic drugs (DMARDs) or biologic agents? The pros and cons of treating patients with UA are examined.

Review of treatment response in rheumatoid arthritis: assessment of heterogeneity

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic, systemic, progressive, inflammatory disorder. The primary goals of treatment in RA are to reduce the signs and symptoms of disease, prevent progression of joint damage and improve patients' physical function. Patients with different sociodemographic characteristics, varying degrees of severity of illness, and comorbidities tend to exhibit differential response to treatment. The purpose of this review was to identify a broad set of factors that are associated with and/or predictive of RA treatment response and determine those that warrant further research.

RESEARCH DESIGN AND METHODS

A comprehensive review of the literature from the last 10 years was performed using three key databases (PubMed, EMBASE, and Cochrane). All relevant articles that met the inclusion/exclusion criteria were selected and scored for their levels of evidence using the National Institute of Clinical Excellence (NICE) scoring method. Data on study design, interventions and treatment outcomes were abstracted using a structured abstraction table.

RESULTS

A total of 30 articles were included in the review and data abstraction. Besides gender, baseline clinical variables such as C-reactive protein level, erythrocyte sedimentation rate, measures of disease activity, and Health Assessment Questionnaire scores (based on five patient-centered dimensions) were consistently associated with treatment response over time.

CONCLUSIONS

This comprehensive literature review identified several factors associated with treatment response which might be valuable to include as relevant measures in future studies of RA treatment. Inclusion of these factors, particularly those in the clinical and sociodemographic domains, in the design of future trials will further the understanding that ultimately may help clinicians deliver targeted treatment to community practice RA patients, thus resulting in improved patient outcomes.

Effectiveness of Leflunomide in Patients with Juvenile Idiopathic Arthritis in Clinical Practice

Objective.

To evaluate the effectiveness of leflunomide in children with juvenile idiopathic arthritis (JIA) as used in actual clinical practice.

Methods.

We conducted a retrospective review of medical records of patients with JIA who initiated leflunomide treatment between April 2001 and October 2006. Data derived from these charts included patient baseline characteristics, reason for starting leflunomide, adverse events, joint outcomes, Childhood Health Assessment Questionnaire (CHAQ) scores, visual analog scale pain and well-being scores, and current treatment status.

Results.

Fifty-eight patients (33 female, 25 male) were included in this study. Forty-eight patients were switched from methotrexate (MTX) to leflunomide, primarily because of MTX-related adverse events, and leflunomide was added to ongoing MTX in 10 patients. The mean duration of leflunomide therapy was 1.45 years. The mean swollen joint count decreased from 1.40 at treatment initiation to 0.60 at last followup, while the mean tender joint count decreased from 1.83 to 0.29. Improvements were also observed in CHAQ, pain, and well-being scores. At last followup, 44.8% of patients were continuing leflunomide therapy, 29.3% had discontinued because of remission, and the rest had discontinued treatment because of side effects (22.4%) or other reasons (3.4%).

Conclusion.

Leflunomide treatment, as employed in actual clinical practice, was well tolerated and resulted in substantial improvements in joint and functional status outcomes in children with JIA. Approximately 30% of the patients attained remission during leflunomide therapy. Leflunomide is thus a safe and effective alternative for patients with JIA who cannot tolerate or do not respond to MTX monotherapy.

[Rheumatoid arthritis today]

Advances in the therapy of rheumatoid arthritis with disease modifying antirheumatic drugs (DMARD) such as methotrexate and biological response modifiers in particular, have turned a chronic progressive disease with significant invalidity and mortality into one that can be well controlled. To prevent irreversible damage, early diagnosis is essential. DMARD therapy needs to be instituted within three months after symptom onset - a clinical and organisational challenge. Long term DMARD therapy is monitored using standardized scores and modified whenever not sufficiently successful. Analgesia, physiotherapy and occupational therapy as well as orthopaedic surgery play important roles in the management of rheumatoid arthritis. Consequent multimodal therapy can decisively influence the course of the disease and prevent or at least minimize damage.