AB0136 ASSESSING THE RELATIONSHIP AMONG OBESITY, GENETIC POLYMORPHISM, AND CLINICAL PARAMETERS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:

Several study suggested body mass index(BMI) may influence development of rheumatoid arthritis(RA). There are conflicting reports concerning the impact of high BMI on development of RA, but several reports of obese on drug resistance and functional impairment. The relationship of genetic polymorphism on obesity is unclear in RA.

Objectives:

To examine the relationship among BMI, genetic polymorphism of obesity, disease activity of RA, laboratory parameters, and therapeutic agent of RA.

Methods:

We have carried out a retrospective observational study by systematically analyzing medical records of total 289 patients diagnosed with RA in Shinko Hospital between March 2016 and December 2019. We also conducted genotyping single nucleotide polymorphisms (SNPs) including FTO (rs1558902 and rs9939609), UCP1 (rs1800592), ADR2(rs1042713) and ADR3(rs4994) after informed consent. Obesity was defined as BMI over than 25 and patients were divided between obese (“Ob”) and non-obese (“non-Ob”). These SNPs, DAS28CRP, laboratory parameters, methotrexate dose, use of biological DMARDs were compared between Ob and non-Ob patients.

Results:

Of these 289 patients, 82.7% was female, mean age was 61.9 years and BMI was 22.4. Univariate logistic regression showed differences (p<0.1) between Ob and non Ob groups in UCP1 gene mutation(63.6% vs 78%, P=0.018), DAS(2.24 vs 1.99, P=0.033),triglyceride abnormality(23.8% vs 9.3%, P=0.021), HDL(56 vs 71, P=0.00009), HbA1c abnormality(26.5% vs 12.1%, P=0.019),γGTP(32 vs 21, P=0.00037), ALP (253 vs 230, P=0.0058), ALT (26.5 vs 20, P=0.029),and MTX dose(6 vs 8, P=0.066). Multivariate logistic regression showed that Ob group was significantly associated with HDL(OR=0.976, 95%CI 0.958 to 0.995), UCP1 gene mutation(OR=0.446, 95%CI 0.202 to 0.984), γGTP(OR=2.321, 95%CI 1.269 to 4.245), and MTX dose(OR=0.866, 0.784 to 0.957).

Conclusion:

Obesity in patients with RA had significant positive correlation with γGTP, and negative correlation with HDL, UCP gene mutation and MTX dose.

Disclosure of Interests:

None declared

POS0868 THE FORMULA TO PREDICT TACROLIMUS CONCENTRATION ACCORDING TO GENOTYPING OF CYP3A5 IS USEFUL FOR EFFECTIVE TREATMENT IN INTERSTITIAL LUNG DISEASE WITH DERMATOMYOSITIS

Background:

Tacrolimus (TAC), an immunosuppressant, can be used in second-line maintenance therapy for interstitial lung disease (ILD) in patients with dermatomyositis (DM) [1]. Although some studies reported the clinical efficacy of initial high-trough levels of TAC in combination with GC and IVCY in induction therapy for severe DM-ILD [2], there have been no useful clinical tools for deciding suitable initial dose of TAC. Genotype of polymorphisms in cytochrome P450 (CYP) 3A5 enzyme was reported to play an important role in pharmacokinetics of TAC [3], and we made a formula for deciding initial dose of TAC according to CYP3A5 genotypes in our previous study.

Objectives:

In our previous study (retrospective study), we set the target trough according to the severity for nine DM-ILD patients, six of whom were CYP3A5 *3/*3 and investigated the dose of TAC that could attain the trough using their CYP3A5 genootyping. Using these results, we developed a formula for deciding initial daily dose of TAC (target trough*weight / [(151.1, if CYP3A5 *3/*3) or (86.5, if CYP3A5 *1 allele)]). In this study, we prospectively examined the usefulness and accuracy of this formula.

Methods:

We introduced TAC for new six DM-ILD patients who visited our hospital between November 2019 and May 2020 (prospective study). The starting dose of TAC was decided by using the formula. We assessed the association between predicted and observed trough concentration of TAC at first measurement date (from day 2 to day4), using linear regression analysis. We also assessed the days for attaining the target trough concentration between the patients using the formula (prospective group) and six patients with CYP3A5 *3/*3 (retrospective group).

Results:

CYP3A5 genotype of all six DM-ILD patients were *3/*3 and underwent the TAC treatment by using the formula. The predicted and observed trough concentration of first measurement date were significantly correlated in the patients (r 2= 0.897, p=0.0041) (Fig.1). Compared with our retrospective study, target trough was more quickly attained in patients of the prospective study (Fig.2).

Conclusion:

The formula which we made for attainment target trough concentration based on CYP3A5 genotype was useful for deciding the starting dose of TAC. We also showed that we could attain the target trough concentration at early stage of initial treatment by using the formula.

References:

[1]Oddis CV and Aggarwal R. Nat Rev Rheumatol 2018;14(5):279-89.

[2]Suzuka T et al. Int J Rheum dis 2019;22: 303-13.

[3]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Figure 1.

Correlation of predicted and observed tacrolimus trough concentration at first measurement in the prospective study

Figure 2.

Days to attain the target trough concentration of tacrolimus in the prospective group and the retrospective group

Disclosure of Interests:

None declared

FRI0129 DEVELOPMENT OF A PREDICTION MODEL FOR MAXIMUM METHOTREXATE (MTX) DOSE WITHOUT HEPATOTOXICITY USING AN INDEX OF ERYTHROCYTE MTX-POLYGLUTAMATE (MTXPG) LEVELS SPECULATED BY CLINICAL AND GENETIC MARKERS

Background:

MTX is transported into cells and retained long after polyglutamation. MTXPG level can predict response and possibly adverse effects of MTX. We reported erythrocyte MTXPG concentrations efficiently discriminated patients with and without hepatotoxicity1. We also developed genetic and clinical prediction models for efficacy and hepatotoxicity of MTX2. In the present study, we firstly investigated the effects of clinical and secondly genetic variables on the concentration of total MTXPG and determined oral maximum MTX dose without hepatotoxicity using these variables.

Objectives:

To develop a prediction model for maximum MTX dose without hepatotoxicity.

Methods:

Concentrations of erythrocyte MTX-PG (PG1 to PG4) were detected by LC-MS/MS and calculated total MTXPG as sum of them. MTX-PGn levels were measured in 265 RA patients including 40 patients with elevated AST or ALT (≥ 60 U/L; 1.5 times of upper limits) and the 6 SNPs of 6 gens related to MTXPG metabolism were identified by RT-PCR.

Results:

Total concentrations of MTXPG were 141.3 ± 86.5 and 87.6 ± 47.8 nmol/L (mean±SD) in 40 RA patients with hepatotoxicity and 225 patients without, respectively (p<0.0001). By ROC analysis, the two groups were most efficiently discriminated with cutoff concentration of 100.0 nmol/L (AUC 0.731). Next, genetic and clinical model to speculate the MTXPG concentration was established by multivariate analysis using 4 clinical and 3 genetic variables which were selected from 20 clinical and 6 genetic variables by univariate analysis (p<0.1). Finally, a speculation model for MTXPG concentration by 4 clinical variables (MTX dose, BMI, RBC count, and creatinine) and one genetic variable (GGH c.452C>T) was developed (Figure). When MTXPG concentration of 100 nmol/L was applied to the model, maximum MTX dose without hepatotoxicity was calculated for each patient asMTX dose (mg) = {100 (MTXPG) – 96 + 1.7*BMI + 28*RBC - 120*creatinine - 19.3*GGH(C/T)} / 7.7. Real dose of oral MTX exceeded the calculated dose in 23 of 40 patients (57.5%) with hepatotoxicity, whereas it exceeded in 95 of 223 patients (42.6%) without hepatotoxicity (OR 1.82, p=0.081).

Conclusion:

Maximum MTX dose without hepatotoxicity was speculated by several clinical and genetic markers without measurement of erythrocyte MTX-PG concentrations.

References:

[1]Takahashi M, et al: Clinical Pathology (Rinsho Byori), 67:433-442, 2019.

[2]Onishi A, et al: The Pharmacogenomics J, doi.org/10.1038/s41397-019-0134-9, 2019

Disclosure of Interests:

Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies, Soshi Takahashi: None declared, Miho Takahashi: None declared, Toshiharu Saito: None declared, Katsuyuki Yoshida: None declared, Motoko Katayama: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Akira Onishi Speakers bureau: AO received a speaker fee from Chugai, Ono Pharmaceutical, Eli Lilly, Mitsubishi-Tanabe, Asahi-Kasei, and Takeda, Masakazu Shinohara: None declared, Saori Hatachi: None declared

SAT0154 EXAMINATION OF CYP3A5 GENOTYPE IS USEFUL FOR INTRODUCTION OF TACROLIMUS TREATMENT IN OUTPATIENTS WITH RHEUMATIC DISEASES

Background:

Though several studies showed the efficacy of tacrolimus (TAC) in patients with rheumatoid arthritis (RA) in a dose-depending manner [1], the relationship between efficacy and concentration of TAC remained unclear. Genetic polymorphisms of cytochrome P450 (CYP) 3A5 were reported not only to play an important role in pharmacokinetics of TAC but also to have an influence on clinical outcomes in patients of rheumatic diseases. Several reports showed that the blood concentration of TAC in patients with a CYP3A5 *1 allele (EX, expressor) was lower than that of patients with a CYP3A5 *3/*3 (NEX, non-expressor) [2].

Objectives:

To assess the relationship between efficacy and concentration of TAC in patients with RA, and to examine the usefulness of CYP3A5 genotype screening to detect outpatients suitable for TAC treatment.

Methods:

We examined the relationship between disease activity score (DAS) 28-CRP and concentration of TAC in patients with RA. TAC was taken after the evening meal and blood samples were taken 12±4h after TAC administration. Next we investigated the relationship between genotype frequencies of CYP3A5 and concentration of TAC in patients with rheumatic disease without having renal dysfunction (eGFR<60) and also investigated the influence of concomitant drugs, such as strong inhibitors of CYP3A4/5 or metabolized by CYP3A4/5, to C/D value in each NEX and EX group. The blood concentration of TAC normalized to the corresponding dose per body weight (C/D, ng/ml per mg/kg) was analyzed according to genetic variation in CYP3A5. Furthermore we investigated the relationship between genotype frequencies of CYP3A5 and concentration of TAC in patients with rheumatic disease at first visit and second visit after starting TAC administration to assess the possibility for making rapid attainment of enough concentrations of TAC in early stage of treatment.

Results:

The concentration of TAC tended to be negatively correlated with the disease activity of RA. The C/D value in the NEX group (n=16) was 124.7±62.1, which was significantly higher than that in the EX group (n=23; 67.7±29.8;P<0.001). When comparing patients using concomitant drugs which are strong inhibitors of CYP3A4/5 or metabolized by CYP3A4/5 with patients not using those drugs, the each C/D value of NEX group was 122.9±52.3 (n=9) and 126.9±77.3 (n=7), and that of EX group was 71.3±32.2 (n=12) and 63.8±28.0 (n=11). There were no significant differences between these groups. In NEX group, when comparing concentration of TAC at first visit and second visit after starting TAC administration, the each concentration of TAC was 3.14±2.06 ng/ml and 3.80±2.20 ng/ml in NEX group (n=10), and that of TAC was 1.82±0.82 ng/ml and 2.69±1.52 ng/ml (n=11) in EX group (Figure).

Conclusion:

TAC showed efficacy in patients with RA in a concentration-dependent manner. EX patients may be impossible to achieve enough concentration of TAC even though using TAC of 3mg/day, approved dose for patients with RA in Japan, and NEX patients could make rapid attainment of enough concentrations of TAC in early stage of treatment, suggesting that we should consider induction of TAC only in NEX outpatients. Furthermore, drugs only slightly affected concentration of TAC in this study, suggesting that we can use TAC without any special attention to concomitant drugs.

References:

[1]Furst DE et al. Arthritis Rheum 2002;46:2020-28.

[2]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Acknowledgments:

none

Disclosure of Interests:

Soshi Takahashi: None declared, Shinji Horibata: None declared, Saori Hatachi: None declared, Miho Takahashi: None declared, Motoko Katayama: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Katsuyuki Yoshida: None declared, Kennosuke Yorifuji: None declared, Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies

FRI0246 GENOTYPING OF CYP3A5 IS USEFUL FOR TREATMENT WITH TACROLIMUS IN INTERSTITIAL LUNG DISEASE IN DERMATOMYOSITIS

Background:

Tacrolimus (TAC), an immunosuppressant, can be used in second-line maintenance therapy of interstitial lung disease (ILD) in patients with dermatomyositis (DM) [1]. In Japan, TAC is approved for DM-ILD and often used as induction therapy for severe cases, especially in patients with anti-MDA5-Ab (melanoma differentiation-associated gene 5 antibody) positive, in combination with glucocorticoids (GC) and intravenous cyclophosphamide (IVCY). Some studies reported the clinical efficacy of initial high-trough level TAC for DM-ILD in combination with GC and IVCY [2]. Adjustment to target concentration of TAC in early stage of treatment is important for controlling disease activity. The concentration of TAC depends on genetic polymorphisms in cytochrome P450 (CYP) 3A5 enzyme expression and several reports showed that the bioavailability and concentration of TAC in patients with a CYP3A5 *1 allele (*1) was lower than those with a CYP3A5 *3/*3 (*3/*3) [3].

Objectives:

To examine the usefulness of CYP3A5 polymorphisms in decision of initial dose to achieve the target concentration of TAC and to evaluate the clinical efficacy in patients of DM-ILD who achieved the enough concentration of TAC in early stage of treatment.

Methods:

We investigated CYP3A5 polymorphisms and TAC concentration in 9 patients of DM-ILD without renal dysfunction (eGFR>60). TAC was taken after both morning and evening meals and blood samples were taken 12h after TAC administration. The blood concentration of TAC normalized to the corresponding dose per body weight (C/D, ng/ml per mg/kg) was analyzed according to genetic variation in CYP3A5. Based on the retrospective analyzation, we chose proper dose of TAC in initial treatment for an anti-MDA5-Ab positive DM-ILD patient, whose genotype was *3/*3.

Results:

The C/D value in the *3/*3 group (n=6) was 154.6±25.6, which was significantly higher than that in the *1 group (n=3;79.0±2.8; P =0.028). When the target concentration was set at 5-10 ng/ml, the required dose was (0.0316 to 0.0633) mg/kg in the *1 group and (0.0162 to 0.0324) mg/kg in the *3/*3 group. The *1 group needs more dose than that of the *3/*3 group to achieve the same target trough of TAC, suggesting that the examination of CYP3A5 genotype is useful for deciding initial dose of TAC (Fig.1). We started TAC 6mg/day with setting target concentration at 15-20 ng/ml to a *3/*3 patient of DM-ILD with anti-MDA5-Ab positive, resulting in good clinical course with making rapid attainment of target concentration in early stage of treatment (Fig.2).

Conclusion:

To examine the CYP3A5 genotype is valuable for deciding the initial dose of TAC, especially in patients who need achievement to target concentration rapidly.

References:

[1]Oddis CV and Aggarwal R. Nat Rev Rheumatol 2018;14(5):279-89.

[2]Suzuka T et al. Int J Rheum dis 2019;22: 303-13.

[3]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Acknowledgments:

none

Disclosure of Interests:

motoko katayama: None declared, Shinji Horibata: None declared, Soshi Takahashi: None declared, Miho Takahashi: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Katsuyuki Yoshida: None declared, Saori Hatachi: None declared, Kennosuke Yorifuji: None declared, Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies

Acute Chlamydia pneumoniae infection in the pathogenesis of autoimmune diseases

Autoimmune diseases have several etiologies. Acute Chlamydia pneumoniae (C. pneumoniae) infection may be involved in the pathogenesis of several autoimmune diseases. In this study, 82 patients with several autoimmune diseases and 70 controls were enrolled, and acute C. pneumoniae infection has been evaluated by monitoring the levels of IgM antibody. Chlamydia pneumoniae IgM positive results were observed in 29% (P < 0.05) of the patients with several autoimmune diseases and in 10% of the controls. Chlamydia pneumoniae IgM positive cases were more frequent among the patients with rheumatoid arthritis (RA; 30%, P < 0.05), systemic lupus erythematosus (SLE; 28.0%, P < 0.05), dermatomyositis/polymyositis (23%, NS), myeloperoxidase-antineutrophil cytoplasmic autoantibody (MPO-ANCA)-associated vasculitis (33%, NS), adult onset of Still's disease (29%, NS) and giant cell arteritis/Takayasu arteritis (50%, NS) than among the controls. This positive frequency was statistically significant in RA and SLE. These results suggest that acute C. pneumoniae infection is probably involved in the pathogenesis of autoimmune diseases.