The effect of gene polymorphisms on patient responses to rheumatoid arthritis therapy

Clinical Value of IL6R Gene Variants as Predictive Biomarkers for Toxicity to Tocilizumab in Patients with Rheumatoid Arthritis

Tocilizumab is a first-line biologic disease-modifying anti-rheumatic drug (bDMARD) that inhibits the interleukin-6 (IL-6) pathway by antagonizing the IL-6 receptor (IL-6R). Tocilizumab is widely used to treat rheumatoid arthritis (RA), a prevalent autoimmune disease that can cause irreversible joint damage and disability. Although many bDMARDs have been developed for RA, there is a lack of validated biomarkers which could guide personalized medicine strategies. To evaluate whether single-nucleotide polymorphisms (SNPs) in the IL6R gene could predict tocilizumab toxicity in patients with RA, we conducted a retrospective cohort study of 88 patients treated with tocilizumab. Six SNPs previously described in the IL6R gene were genotyped (rs12083537, rs11265618, rs4329505, rs2228145, rs4537545, and rs4845625). Using parametric tests, we studied the association between the SNPs and hepatotoxicity, infection, hypersensitivity, gastrointestinal, hematological, and dyslipidemia adverse events (AEs). We found associations between dyslipidemia and rs4845625 and between hematological AEs and rs11265618 and rs4329505. No further associations were found for the remaining SNPs and other AEs. Our findings support the potential clinical value of SNPs in the IL6R gene as predictive biomarkers for toxicity to tocilizumab in patients with RA.

Role of IL6R Genetic Variants in Predicting Response to Tocilizumab in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a prevalent autoimmune disease characterized by chronic arthritis that may lead to irreversible joint damage and significant disability. Patients with RA are commonly treated with Tocilizumab (TCZ), an IL-6 receptor (IL-6R) antagonist, but many patients refractorily respond to this therapy. Identifying genetic biomarkers as predictors of TCZ response could be a key to providing a personalized medicine strategy. We aimed to evaluate whether functional single nucleotide polymorphisms (SNPs) in the IL6R gene could predict TCZ response in patients with RA. We retrospectively included 88 RA patients treated with TCZ. Six SNPs previously described in the IL6R gene (rs12083537, rs11265618, rs4329505, rs2228145, rs4537545, and rs4845625) were genotyped in DNA samples from these patients. Using parametric tests, we evaluated the association between these polymorphisms and clinicopathological features. Responses to treatments were assessed at six months using three variables: a quantitative improvement in Disease activity score including 28 joints (DAS28), a satisfactory European League Against Rheumatism (EULAR) response, and low disease activity (LDA) achievement. The three response variables studied were associated with genetic variant rs4845625, and no association was found with the other five SNPs. Our findings support the potential clinical value of SNPs in the IL6R gene as predictive biomarkers for TCZ response.

Current Understanding of an Emerging Role of HLA-DRB1 Gene in Rheumatoid Arthritis-From Research to Clinical Practice

Rheumatoid arthritis (RA) is an autoimmune disease with an unclear pathogenic mechanism. However, it has been proven that the key underlying risk factor is a genetic predisposition. Association studies of the HLA-DRB1 gene clearly indicate its importance in RA morbidity. This review presents the current state of knowledge on the impact of HLA-DRB1 gene, functioning both as a component of the patient’s genome and as an environmental risk factor. The impact of known HLA-DRB1 risk variants on the specific structure of the polymorphic HLA-DR molecule, and epitope binding affinity, is presented. The issues of the potential influence of HLA-DRB1 on the occurrence of non-articular disease manifestations and response to treatment are also discussed. A deeper understanding of the role of the HLA-DRB1 gene is essential to explore the complex nature of RA, which is a result of multiple contributing factors, including genetic, epigenetic and environmental factors. It also creates new opportunities to develop modern and personalized forms of therapy.

Are gene polymorphisms related to adverse events of methotrexate in patients with rheumatoid arthritis? A retrospective cohort study based on an updated meta-analysis

Aims:

We performed an updated meta-analysis to verify correlations between gene polymorphisms and adverse events in methotrexate (MTX)-treated rheumatoid arthritis (RA) patients. Then, we conducted a retrospective cohort study of Han Chinese in China.

Methods:

Relevant studies were collected from the PubMed database and the EMBASE database until December 2017. Pre-allele, dominant, recessive, codominant, and homozygotic models were applied. In addition, a retrospective cohort study enrolling 162 RA patients treated with MTX was conducted. Single nucleotide polymorphism (SNP) genotyping was analyzed by PCR and product sequencing.

Results:

A total of 39 studies were included in 20 meta-analyses; meta-analysis showed a significant association between MTX-related toxicity and 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C>T(rs1801133) polymorphism in East Asian RA patients, and significant associations were observed between MTX-related toxicity and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (ATIC) 347C>G (rs2372536), reduced folate carrier 1 (RFC-1) 80G>A (rs1051266), and adenosine triphosphate-binding cassette B1 (ABCB1) 3435C>T(rs1045642) polymorphisms in European RA patients but not in East Asian RA patients. Moreover, in our retrospective cohort study, ATIC 347C>G(rs2372536) and ABCB1 3435C>T(rs1045642) polymorphisms were not associated with MTX-related toxicity. However, a significant association was observed between MTX-related toxicity and RFC-1 80G>A (rs1051266) polymorphism in Chinese Han RA patients.

Conclusion:

Evidence-based results suggest that the MTHFR 677C>T(rs1801133), ATIC 347C>G(rs2372536), RFC-1 80G>A (rs1051266), ABCB1 3435C>T(rs1045642) polymorphisms are associated with MTX-related toxicity. Larger and more stringent study designs may provide more accurate findings for the effects of these SNPs on MTX-related toxicity, and larger sample-size studies of the Chinese Han population should be conducted for further validation.

The evolution in our understanding of the genetics of rheumatoid arthritis and the impact on novel drug discovery

Introduction: Rheumatoid arthritis (RA) is an autoimmune disease that is characterized by chronic inflammation of the joints and affects 1% of the population. Polymorphisms of genes that encode proteins that primarily participate in inflammation may influence RA occurrence or become useful biomarkers for certain types of anti-rheumatic treatment.Areas covered: The authors summarize the recent progress in our understanding of the genetics of RA. In the last few years, multiple variants of genes that are associated with RA risk have been identified. The development of new technologies and the detection of new potential therapeutic targets that contribute to novel drug discovery are also described.Expert opinion: There is still the need to search for new genes which may be a potential target for RA therapy. The challenge is to develop appropriate strategies for achieving insight into the molecular pathways involved in RA pathogenesis. Understanding the genetics, immunogenetics, epigenetics and immunology of RA could help to identify new targets for RA therapy. The development of new technologies has enabled the detection of a number of new genes, particularly genes associated with proinflammatory cytokines and chemokines, B- and T-cell activation pathways, signal transducers and transcriptional activators, which might be potential therapeutic targets in RA.

Pharmacotherapy Pearls in Rheumatology for the Care of Older Adult Patients: Focus on Oral Disease-Modifying Antirheumatic Drugs and the Newest Small Molecule Inhibitors

Providing safe and effective pharmacotherapy to geriatric patients with rheumatologic disorders is challenging. Multidisciplinary care involving rheumatologists, primary care physicians, and other specialties can optimize benefit and reduce adverse outcomes. Oral disease-modifying antirheumatic drugs, including methotrexate, hydroxychloroquine, sulfasalazine, and leflunomide, and the small molecule inhibitors tofacitinib and apremilast have distinctive monitoring requirements and specific adverse reaction profiles. This article provides clinically relevant pearls for use of these interventions in older patients.

Replication study of polymorphisms associated with response to methotrexate in patients with rheumatoid arthritis

About 70 genetic studies have already addressed the need of biomarkers to predict the response of patients with rheumatoid arthritis (RA) to methotrexate (MTX) treatment. However, no genetic biomarker has yet been sufficiently validated. Here, we aimed to replicate a selection of 25 SNPs in the largest collection of patients up to date, which consisted of 915 patients treated with MTX. The change in disease activity (measured as ΔDAS28) from baseline was considered the primary outcome. In addition, response according to widely used criteria (EULAR) was taken as secondary outcome. We considered consistency between outcomes, P values accounting for the number of SNPs, and independence from potential confounders for interpretation of the results. Only the rs1801394 SNP in MTRR fulfilled the high association standards. Its minor allele was associated with less improvement than the major allele according to ΔDAS28 (p = 0.0016), and EULAR response (p = 0.004), with independence of sex, age, baseline DAS28, smoking, seropositivity, concomitant corticosteroid use or previous treatments. In addition, previous evidence suggests the association of this SNP with response to MTX in another autoimmune disease, juvenile idiopathic arthritis, and with high intracellular folate levels, which could contribute to poor response.

Systematic review and meta-analysis: pharmacogenetics of anti-TNF treatment response in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects ~1% of the Caucasian population. Over the last decades, the availability of biological drugs targeting the proinflammatory cytokine tumour necrosis factor α, anti-TNF drugs, has improved the treatment of patients with RA. However, one-third of the patients do not respond to the treatment. We wanted to evaluate the status of pharmacogenomics of anti-TNF treatment. We performed a PubMed literature search and all studies reporting original data on associations between genetic variants and anti-TNF treatment response in RA patients were included and results evaluated by meta-analysis. In total, 25 single nucleotide polymorphisms were found to be associated with anti-TNF treatment response in RA (19 from genome-wide association studies and 6 from the meta-analyses), and these map to genes involved in T cell function, NFκB and TNF signalling pathways (including CTCN5, TEC, PTPRC, FCGR2A, NFKBIB, FCGR2A, IRAK3). Explorative prediction analyses found that biomarkers for clinical treatment selection are not yet available.

Are gene polymorphisms related to treatment outcomes of methotrexate in patients with rheumatoid arthritis? A systematic review and meta-analysis

Aim: Identifying the predictors of responsiveness and adverse events in methotrexate (MTX) treated patients with rheumatoid arthritis (RA) has been the focus of most concern, but still without consistent consensus. Methods: PubMed and OVID EMBASE were searched to collect relevant studies that addressed correlations between gene polymorphisms and efficacy and/or toxicity in MTX-treated RA patients. Allelic, recessive, dominant and over-dominant model were applied. Results: A total of 68 studies were included. For associations with efficacy, AMPD1 34C>T polymorphism was related to responsiveness in dominant model (odds ratio [OR]: 1.77; 95% CI: 1.19–2.63) and over-dominant model (OR: 1.59; 95% CI: 1.04–2.45). ATIC T675C polymorphism had association with responsiveness in recessive model (OR: 2.54; 95% CI: 1.23–5.26). For associations with toxicity, polymorphisms in TYMS 1494 del6 and FPGS rs10106 were correlated to absenting overall adverse events in recessive model (OR: 0.68; 95% CI: 0.49–0.95) and dominant model (OR: 0.54; 95% CI: 0.35–0.83) respectively while MTHFR C677T was associated with presenting overall adverse events in allelic model (OR: 1.29; 95% CI: 1.02–1.63), recessive model (OR: 1.38; 95% CI: 1.00–1.89) and dominant model (OR: 1.41; 95% CI: 1.02–1.94). Conclusion: Polymorphisms in AMPD1 34C>T and ATIC T675C predict responsiveness. The absence of TYMS 1494 del6 and FPGS rs10106 and presence of MTHFR C677T predict adverse events in RA patients treated with MTX. Moreover, variations of the associations were found between Caucasians and non-Caucasians.

Influence of IL6R gene polymorphisms in the effectiveness to treatment with tocilizumab in rheumatoid arthritis

In the present study, we aimed to investigate the influence of clinical parameters and single-nucleotide polymorphisms of interleukin-6 receptor (rs12083537, rs2228145, rs4329505 and rs11265618) on response to tocilizumab, TCZ (European League Against Rheumatism (EULAR) response, remission, low disease activity (LDA) and improvement of DAS28). We performed a retrospective cohort study in patients with Rheumatoid Arthritis (RA) treated with TCZ for 12 months. Multivariable analysis showed that the only variable independently associated to satisfactory EULAR response (odds ratio (OR): 0.61; 95% of confidence interval (CI)_95%: 0.42, 0.88; P=0.008), remission (OR: 0.51; CI_95%: 0.35, 0.75; P=0.001), LDA (OR: 0.41; CI_95%: 0.24, 0.72; P=0.002) and improvement in DAS28 (B=-0.32; CI_95%): -0.47, -0.17; P=7.5 × 10^-5) at 12 months was lower number of previous biological therapy (BT). High baseline DAS28 was also associated with a greater decrease in DAS28 at 12 months of treatment (B=0.99; CI_95%: 0.79, 1.20; P=1.5 × 10^-14). Those patients who were carriers of AA genotypes for rs12083537 (OR: 13.0; CI_95%: 2.31, 72.91; P=0.004) and CC for rs11265618 (OR: 12.15; CI_95%: 2.18, 67.81; P=0.004) had better LDA response at 12 months of treatment with TCZ. In conclusion, RA patients treated with TCZ showed better EULAR response, remission, LDA and DAS28 improvement rates when a lower number of BT were previously administered. The AA genotype for rs12083537 and CC for rs11265618 polymorphisms for may act as predictors of good response LDA.

Pharmacotherapy Pearls for the Geriatrician: Focus on Oral Disease-Modifying Antirheumatic Drugs Including Newer Agents

Providing safe and effective pharmacotherapy to the geriatric patients with rheumatological disorders is an ongoing struggle for the rheumatologist and geriatrician alike. Cohesive communication and partnership can improve the care of these patients and subvert adverse outcomes. Disease-modifying antirheumatic drugs, including methotrexate, hydroxychloroquine, sulfasalazine, and leflunomide, and the newest oral agent for treatment of rheumatoid arthritis, tofacitinib, have distinctive monitoring and adverse effect profiles. This article provides the general practitioner or geriatrician with clinically relevant pearls regarding the use of these interventions in older patients.

Genetic and clinical biomarkers of tocilizumab response in patients with rheumatoid arthritis

The aim of this study was to investigate the influence of clinical and genetic factors on response to tocilizumab (TCZ) response, remission, low disease activity (LDA) and DAS28 improvement. A retrospective cohort study in 79 RA patients treated with TCZ during 6/18 months of therapy was conducted. CD69(rs11052877), GALNT18(rs4910008), CLEC2D(rs1560011), KCNMB1(rs703505), ENOX1(rs9594987), rs10108210, and rs703297 gene polymorphisms, identified in a recent GWAS as putative predictors of TCZ response, were analysed. Variables independently associated to satisfactory EULAR response at 6 months were GALNT18-CC genotype (ORCC/T-:12.8; CI95%:1.5,108.7; p=0.02), CD69 gene polymorphism (ORAA/GG:17.2; CI95%:2.5,119.6; p=0.004) and lower number of previous biological therapy, BT (OR: 0.45; CI95%:0.3, 0.7; p=0.001). The factors independently associated to higher remission were lower number of previous BT (OR:0.56; CI95%:0.38, 0.82; p=0.003), and GALNT18 CC genotype (ORCT/CC:0.09; CI95%:0.02,0.45;p=0.004; ORTT/CC:0.14; CI95%:0.02,0.79; p=0.026). The A-allele of CD69 (ORA_/GG:6.68;CI95%:1.68,26.51;p=0.007) and lower number of previous BT (OR:0.50; CI95%:0.32,0.77; p=0.002) were independent factors capable to predict higher LDA rates at 6 months. Independent factors associated to higher improvement in DAS28 at 6 months were CD69-AA genotype (B=-0.56; CI95%:-1.09, -0.03; p=0.039), GALNT18-CC genotype (B=-0.88;CI95%:-1.49, -0.27; p=0.005), subcutaneous administration (B=1.03; CI95%:0.44,1.62; p=0.001) and higher baseline DAS28 (B=0.82; CI95%:0.59, 1.05; p=4.9×10(-10)). Lower number of previous BT was the only independent predictor of satisfactory EULAR response (OR:0.60; CI95%:0.34,0.88; p=0.010) and higher remission (OR:0.65; CI95%:0.46,0.93; p=0.018) at 18 months. The C-allele of GALNT18 (ORC-/TT:4.60; CI95%:1.16, 18.27; p=0.03) and lower number of previous BT (OR:0.47; CI95%:0.29,0.74; p=0.001) were independent factors capable to predict higher LDA rates at 18 months. In conclusion, RA patients treated with TCZ showed better EULAR response, remission, LDA and DAS28 improvement rates in patients carrying the GALNT18 C-allele or the CD69 A-allele, particularly when lower number of BT were previously administered.