Pharmacogenetics of disease-modifying antirheumatic drugs in rheumatoid arthritis: towards personalized medicine

Innovative trial approaches in immune-mediated inflammatory diseases: current use and future potential

BACKGROUND

Despite progress that has been made in the treatment of many immune-mediated inflammatory diseases (IMIDs), there remains a need for improved treatments. Randomised controlled trials (RCTs) provide the highest form of evidence on the effectiveness of a potential new treatment regimen, but they are extremely expensive and time consuming to conduct. Consequently, much focus has been given in recent years to innovative design and analysis methods that could improve the efficiency of RCTs. In this article, we review the current use and future potential of these methods within the context of IMID trials.

METHODS

We provide a review of several innovative methods that would provide utility in IMID research. These include novel study designs (adaptive trials, Sequential Multi-Assignment Randomised Trials, basket, and umbrella trials) and data analysis methodologies (augmented analyses of composite responder endpoints, using high-dimensional biomarker information to stratify patients, and emulation of RCTs from routinely collected data). IMID trials are now well-placed to embrace innovative methods. For example, well-developed statistical frameworks for adaptive trial design are ready for implementation, whilst the growing availability of historical datasets makes the use of Bayesian methods particularly applicable. To assess whether and how these innovative methods have been used in practice, we conducted a review via PubMed of clinical trials pertaining to any of 51 IMIDs that were published between 2018 and 20 in five high impact factor clinical journals.

RESULTS

Amongst 97 articles included in the review, 19 (19.6%) used an innovative design method, but most of these were relatively straightforward examples of innovative approaches. Only two (2.1%) reported the use of evidence from routinely collected data, cohorts, or biobanks. Eight (9.2%) collected high-dimensional data.

CONCLUSIONS

Application of innovative statistical methodology to IMID trials has the potential to greatly improve efficiency, to generalise and extrapolate trial results, and to further personalise treatment strategies. Currently, such methods are infrequently utilised in practice. New research is required to ensure that IMID trials can benefit from the most suitable methods.

Pharmacogenetic aspects of methotrexate in a cohort of Colombian patients with rheumatoid arthritis

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug for the treatment of rheumatoid arthritis (RA). However, over time, ~40% of patients may experience therapeutic failure or drug toxicity. The genetic variability of the enzymes involved in the MTX metabolic pathway seem to serve an important role in the eventual therapeutic failure or drug toxicity. Depending on the enzymes affected, the toxicity or the therapeutic response may change. The present study reports some of the polymorphisms identified in enzymes in the MTX metabolic pathway that are present in a group of Colombian patients with RA, and assesses the associations of these polymorphisms with toxicity or therapeutic response to the medication. A total of 400 patients with RA were evaluated, of which 76% were women. the average age was 60.7±13.9 years and the duration of the disease was 13.2±10.9 years. The disease activity scoring method, DAS28-CRP, was used to evaluate the therapeutic response. Toxicity was determined based on reports of adverse events during the evaluation of the patients. The single nucleotide polymorphisms (SNPs) assessed using reverse transcription-PCR in the present study were MTHFR C677T, A1298C, ATIC C347G, RFC-1-G80A, FPGS-AG and DHFR-CT. The SNPs of MTHFR C677T (P=0.05) and A1298C (P=0.048) were significantly associated with the efficacy of MTX, and DHFR-CT (P=0.01) and ATIC C347 (P=0.005) were significantly associated with documented toxicity. Haematological, hepatic or renal toxicity was not associated with any of the SNPs. The results obtained in Colombian patients with RA receiving MTX are similar to those reported in other populations; however, the SNPs associated with a lack of response previously reported in the literature were not observed in our data. The SNPs identified in the present study may be used as biomarkers to predict response to MTX in terms of efficacy and toxicity in Colombian patients with RA.

Total Joint Arthroplasty in Patients with Inflammatory Rheumatic Diseases

Since its introduction, total joint arthroplasty (TJA) has improved the quality of life of patients with degenerative joint disorders. In the last decades, a number of conventional and biological disease-modifying antirheumatic drugs have become available for the treatment of patients with inflammatory rheumatic diseases (IRD), leading to a reduction in the need to undergo TJA. However, TJA is still frequently performed in IRD patients. Both rheumatologists and orthopedics should be aware that patients with IRD have a peculiar perioperative risk profile due to disease-related, patient-related, and surgery-related risk factors. On the basis of current evidence, TJA is a safe procedure for IRD patients as long as an accurate risk stratification and a multidisciplinary approach are applied. We here describe the current strategies for an appropriate surgical management of osteoarthritis in IRD patients and the fascinating opening perspectives that surgeons and clinicians may expect in the future.

SNPs affecting the clinical outcomes of regularly used immunosuppressants

Recent studies have suggested that genomic diversity may play a key role in different clinical outcomes, and the importance of SNPs is becoming increasingly clear. In this article, we summarize the bioactivity of SNPs that may affect the sensitivity to or possibility of drug reactions that occur among the signaling pathways of regularly used immunosuppressants, such as glucocorticoids, azathioprine, tacrolimus, mycophenolate mofetil, cyclophosphamide and methotrexate. The development of bioinformatics, including machine learning models, has enabled prediction of the proper immunosuppressant dosage with minimal adverse drug reactions for patients after organ transplantation or for those with autoimmune diseases. This article provides a theoretical basis for the personalized use of immunosuppressants in the future.

Clinical Pharmacogenetic Models of Treatment Response to Methotrexate Monotherapy in Slovenian and Serbian Rheumatoid Arthritis Patients: Differences in Patient's Management May Preclude Generalization of the Models

Objectives: Methotrexate (MTX) is the first line treatment for rheumatoid arthritis (RA), but nevertheless 30% of patients experience MTX inefficacy. Our aim was to develop a clinical pharmacogenetic model to predict which RA patients will not respond to MTX monotherapy. We also assessed whether this model can be generalized to other populations by validating it on a group of Serbian RA patients.

Methods: In 110 RA Slovenian patients, data on clinical factors and 34 polymorphisms in MTX pathway were analyzed by Least Absolute Shrinkage and Selection Operator (LASSO) penalized regression to select variables associated with the disease activity as measured by Disease Activity Score (DAS28) score after 6 months of MTX monotherapy. A clinical pharmacogenetic index was constructed from penalized regression coefficients with absolute value above 0.05. This index was cross-validated and also independently validated on 133 Serbian RA patients.

Results: A clinical pharmacogenetic index for prediction of DAS28 after 6 months of MTX monotherapy in Slovenian RA patients consisted of DAS28 score at diagnosis, presence of erosions, MTX dose, Solute Carrier Family 19 Member 1 (SLC19A1) rs1051266, Solute Carrier Organic Anion Transporter Family Member 1B1 (SLCO1B1) rs2306283, Thymidylate Synthase (TYMS), and Adenosine Monophosphate Deaminase 1 (AMPD1) rs17602729. It correctly classified 69% of Slovenian patients as responders or nonresponders and explained 30% of variability in DAS28 after 6 months of MTX monotherapy. Testing for validity in another population showed that it classified correctly only 22.5% of Serbian RA patients.

Conclusions: We developed a clinical pharmacogenetic model for DAS28 after 6 months of MTX monotherapy in Slovenian RA patients by combining clinical and genetic variables. The clinical pharmacogenetic index developed for Slovenian patients did not perform well on Serbian patients, presumably due to the differences in patients' characteristics and clinical management between the two groups.

Effect of Artemisia annua extract on treating active rheumatoid arthritis: A randomized controlled trial

OBJECTIVE

To investigate the effect and safety of the complementary use of the extract of Artemisia annua L. (EAA) on treating active rheumatoid arthritis (RA).

METHODS

A randomized controlled clinical trial was performed. All the 159 participates with active RA were randomly assigned to the control group (80 cases) and EAA group (79 cases) using concealed random allocation method. In the control group, patients were medicated with leflflunomide and methotrexate for 48 weeks; and patients in the EAA group were administrated with leflflunomide, methotrexate plus EAA (30 g/d). At the time points of 0, 12, 24 and 48 weeks, the clinical outcome measures, including objective pain score, tenderness score, number of painful joints, number of swollen joints, health assessment questionnaire (HAQ) score for quality of life, levels of serum rheumatoid factor (RF), anti-cyclic citrullinated protein antibodies (CCP-Ab), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), visual analogue score for pain (VAS), and the overall effificacy were detected and recorded.

RESULTS

The objective pain score, number of painful joints and ESR at 12 weeks, tenderness score and HAQ at 24 weeks, and the tenderness score, number of painfull joints, number of swollen joints, HAQ, CRP, RF and CCP-Ab at 48 weeks were signifificantly improved in the EAA group compared with the control group (P<0.01 or P<0.05). At 24 and 48 weeks, the overall effificacy of the EAA group was signifificantly higher than the control group (P<0.01). There were signifificantly higher withdrawal rate of corticosteroids within 12 weeks post-treatment and lower incidence rate of adverse effects in the EAA group compared with the control group (P<0.01 or P<0.05).

CONCLUSION

EAA plus methotrexate and leflflunomide were more effective and safer than the routine use of methotrexate and leflflunomide in the treatment of active RA.

Non-adherence to disease-modifying antirheumatic drugs is associated with higher disease activity in early arthritis patients in the first year of the disease

Introduction

Non-adherence to disease-modifying antirheumatic drugs (DMARDs) hampers the targets of rheumatoid arthritis (RA) treatment, obtaining low disease activity and decreasing radiological progression. This study investigates if, and to what extent, non-adherence to treatment would lead to a higher 28-joint count disease activity score (DAS28) in the first year after diagnosis.

Methods

Adult patients from an ongoing cohort study on treatment adherence were selected if they fulfilled the EULAR/ACR2010 criteria for RA, and were to start with their first DMARDs. Clinical variables were assessed at baseline and every 3 months. Non-adherence was continuously electronically measured and was defined as the proportion of days with a negative difference between expected and observed openings of the medication container out of the 3-month period before DAS28 measurement. Generalized linear mixed models were used to investigate whether the DAS28 related to non-adherence. Covariates included were age, sex, baseline DAS28, rheumatoid factor positivity, anti-cyclic citrullinated peptide antibodies (ACPA) positivity, anxiety, depression, weeks of treatment, number of DMARDs used, education level, use of subcutaneous methotrexate and biological use.

Results

One hundred and twenty patients met the inclusion criteria for RA. During the study period 17 patients became lost to follow-up. There was a decline in adherence over time for all DMARDs except for prednisone. Non-adherence is a predictor of disease activity in the first 6 months of therapy, adjusted for weeks of treatment, baseline DAS28, and baseline anxiety.

Conclusions

Non-adherence relates to disease activity. Therefore, interventions towards enhancing adherence can improve disease outcome.

Repository corticotropin injection in a patient presenting with focal segmental glomerulosclerosis, rheumatoid arthritis, and optic neuritis: a case report

Background

Focal segmental glomerulosclerosis (FSGS) causes scarring or sclerosis of glomeruli that act as tiny filters in the kidneys, damage to which results in diminished ability to properly filter blood, resulting in the urinary loss of plasma proteins and subsequent proteinuria.

Case presentation

A 60-year-old, white female with a history of intermittent proteinuria was referred by her primary care physician for renal dysfunction. Biopsy confirmed FSGS and she was treated with an angiotensin-converting enzyme inhibitor. She also had rheumatoid arthritis (RA) but no active synovitis and was maintained on prednisone 5 mg/d. She also complained of worsening vision in her right eye and was diagnosed with optic neuritis (ON). She remained stable for about 8 months when examination indicated FSGS relapse, and she reported painful RA flares. She was treated with Acthar^® Gel (40 mg biweekly) for 6 months, after which proteinuria and urine protein-to-creatinine ratio decreased to about half. Her ON improved, and she reported that she had fewer RA flares and pain improved by 50%. This case of confirmed FSGS showed an improved response to treatment with Acthar Gel for FSGS with concomitant RA and ON.

Conclusion

This referral case is relevant to primary care practitioners who treat disorders that may be responsive to corticosteroid therapy. The antiproteinuric effects and ancillary improvement in RA and ON symptoms during treatment with Acthar Gel are not entirely explained by its steroidogenic actions. ACTH is a bioactive peptide that, together with α-melanocyte-stimulating hormone, exhibits biologic efficacy by modulating proinflammatory cytokines and subsequent leukocyte extravasation and may have autocrine/paracrine effects in joints. While Acthar Gel was primarily administered in this case to treat proteinuria, it also showed ancillary benefits in patients with concomitant inflammatory disease states.

Estimation of heritability of different outcomes for genetic studies of TNFi response in patients with rheumatoid arthritis

OBJECTIVES

Pharmacogenetic studies of tumour necrosis factor inhibitors (TNFi) response in patients with rheumatoid arthritis (RA) have largely relied on the changes in complex disease scores, such as disease activity score 28 (DAS28), as a measure of treatment response. It is expected that genetic architecture of such complex score is heterogeneous and not very suitable for pharmacogenetic studies. We aimed to select the most optimal phenotype for TNFi response using heritability estimates.

METHODS

Using two linear mixed-modelling approaches (Bayz and GCTA), we estimated heritability, together with genomic and environmental correlations for the TNFi drug-response phenotype ΔDAS28 and its separate components: Δ swollen joint count (SJC), Δ tender joint count (TJC), Δ erythrocyte sedimentation rate (ESR) and Δ visual-analogue scale of general health (VAS-GH). For this, we used genome-wide single nucleotide polymorphism (SNP) data from 878 TNFi-treated Dutch patients with RA. Furthermore, a multivariate genome-wide association study (GWAS) approach was implemented, analysing separate DAS28 components simultaneously.

RESULTS

The highest heritability estimates were found for ΔSJC (h(2)gbayz=0.76 and h(2)gGCTA=0.87) and ΔTJC (h(2)gbayz=0.62 and h(2)gGCTA=0.82); lower heritability was found for ΔDAS28 (h(2)gbayz=0.59 and h(2)gGCTA=0.71) while estimates for ΔESR and ΔVASGH were near or equal to zero. The highest genomic correlations were observed for ΔSJC and ΔTJC (0.49), and the highest environmental correlation was seen between ΔTJC and ΔVASGH (0.62). The multivariate GWAS did not generate excess of low p values as compared with a univariate analysis of ΔDAS28.

CONCLUSIONS

Our results indicate that multiple SNPs together explain a substantial portion of the variation in change in joint counts in TNFi-treated patients with RA. In conclusion, of the outcomes studied, the joint counts are most suitable for TNFi pharmacogenetics in RA.