Long-term efficacy and tolerability of dose-adjusted thiopurine treatment in maintaining remission in inflammatory bowel disease patients with NUDT15 heterozygosity

Real-world NUDT15 genotyping and thiopurine treatment optimization in inflammatory bowel disease: a multicenter study

BACKGROUND

This study evaluated the effectiveness of NUDT15 codon 139 genotyping in optimizing thiopurine treatment for inflammatory bowel disease (IBD) in Japan, using real-world data, and aimed to establish genotype-based treatment strategies.

METHODS

A retrospective analysis of 4628 IBD patients who underwent NUDT15 codon 139 genotyping was conducted. This study assessed the purpose of the genotyping test and subsequent prescriptions following the obtained results. Outcomes were compared between the Genotyping group (thiopurine with genotyping test) and Non-genotyping group (thiopurine without genotyping test). Risk factors for adverse events (AEs) were analyzed by genotype and prior genotyping status.

RESULTS

Genotyping test for medical purposes showed no significant difference in thiopurine induction rates between Arg/Arg and Arg/Cys genotypes, but nine Arg/Cys patients opted out of thiopurine treatment. In the Genotyping group, Arg/Arg patients received higher initial doses than the Non-genotyping group, while Arg/Cys patients received lower ones (median 25 mg/day). Fewer AEs occurred in the Genotyping group because of their lower incidence in Arg/Cys cases. Starting with < 25 mg/day of AZA reduced AEs in Arg/Cys patients, while Arg/Arg patients had better retention rates when maintaining ≥ 75 mg AZA. Nausea and liver injury correlated with thiopurine formulation but not dosage. pH-dependent mesalamine reduced leukopenia risk in mesalamine users.

CONCLUSIONS

NUDT15 codon 139 genotyping effectively reduces thiopurine-induced AEs and improves treatment retention rates in IBD patients after genotype-based dose adjustments. This study provides data-driven treatment strategies based on genotype and identifies risk factors for specific AEs, contributing to a refined thiopurine treatment approach.

Efficacy of optimised thiopurine therapy in patients with moderate-to-severe ulcerative colitis: retrospective long-term follow-up from two randomised trials

OBJECTIVE

The long-term outcome of thiopurine therapy in patients with ulcerative colitis (UC) enrolled in prospective trials have not been evaluated. We aimed to assess the effects of optimised thiopurine maintenance therapy for UC.

METHODS

Long-term data were obtained from patients from our center enrolled in two randomised, prospective, open-label, controlled studies comprising 66 thiopurine-naïve moderate-to-severe patients with UC consisting of a low dose azathioprine (AZA)/allopurinol combination or AZA monotherapy. Following the randomised trials, treatment was adjusted according to adverse effects and metabolites. Patients requiring optimisation initially on AZA monotherapy treatment were switched to low dose AZA in combination with allopurinol, low dose 6-mercaptopurin in combination with allopurinol, or 6-mercaptopurin treatment alone, and those treated with low dose AZA in combination with allopurinol were switched to low dose 6-mercaptopurin in combination with allopurinol or 6-mercaptopurin alone.

RESULTS

A total of 62 patients were included in the analysis; 31 were initially treated with AZA monotherapy and 31 with low dose AZA in combination with allopurinol. Initial treatment was tolerated by 67% patients (7 AZA monotherapy and 28 low dose AZA in combination with allopurinol), increasing to 94% (58 patients) post-adjustment. After a median 52-month follow-up period, 38 (93%) out of the 41 primary responding patients-maintained clinical remission without steroids, biologics or surgery. The four intolerant patients and the 17 not responding to optimisation were more likely to require colectomy (odds ratio 16.36; 95% confidence interval 3.08-87.03, p < 0.0001).

CONCLUSION

Optimised thiopurine therapy demonstrated effective long-term treatment for patients with ulcerative colitis.

Effectiveness and Tolerability of Methotrexate Combined with Biologics in Patients with Crohn's Disease: A Multicenter Observational Study

BACKGROUND

Methotrexate (MTX) combination therapy with biological agents has gained increasing interest. Here, we assessed the efficacy and tolerability of the MTX combination therapy in patients with Crohn's disease (CD).

METHODS

We performed a multicenter observational study with 185 patients with CD with MTX and biologics combination therapy; the patients were recruited from three IBD Clinics in Korea. We evaluated the outcomes of the MTX combination therapy and examined the predictive factors of clinical and endoscopic remission.

RESULTS

MTX was administered orally to 62.7% of patients; the mean dose was 15.5 mg per week, and the mean treatment duration was 36 months. Of the 169 patients treated with MTX combination therapy for over 6 months, the steroid-free clinical remission rates were 34.3%, 26.0%, 29.8%, and 32.7% at 4, 12, 18, and 24 months, respectively. Previous thiopurine use was a significant negatively associated independent factor (p < 0.001), and a higher dose of MTX (≥ 15 mg/week) was a positively associated independent factor of steroid-free clinical remission (p = 0.035). Ninety-six patients underwent follow-up endoscopy after 28 months, and 36 (37.5%) achieved endoscopic remission. Longer disease duration (p = 0.006), ileocolonic type of Montreal location (p = 0.036), and baseline C-reactive protein (CRP) level of more than 5 mg/L (p = 0.035) were significant negatively associated independent factors and a higher dose of MTX (≥ 15 mg/week) was a positively associated independent factor of endoscopic remission (p = 0.037).

CONCLUSIONS

MTX combination therapy with biologics was effective and tolerable in patients with CD.

New genetic biomarkers predicting 5-aminosalicylate-induced adverse events in patients with inflammatory bowel diseases

Background

Notably, 5-aminosalicylates (5-ASA) are vital in treating inflammatory bowel diseases (IBD). The adverse events of 5-ASA rarely occur but they could be fatal.

Objectives

We aimed to discover new genetic biomarkers predicting 5-ASA-induced adverse events in patients with IBD.

Design

This was a retrospective observational study.

Methods

We performed a genome-wide association study on patients with IBD in South Korea. We defined subset 1 as 39 all adverse events and 272 controls; subset 2 as 20 severe adverse events and 291 controls (mild adverse events and control); subset 3 as 20 severe adverse events and 272 controls; and subset 4 as 19 mild adverse events and 272 controls. Logistic regression analysis was performed and commonly found associated genes were determined as candidate single-nucleotide polymorphisms predicting 5-ASA adverse events.

Results

Patients with Crohn's disease (CD) were significantly negatively associated with the development of adverse events compared to patients with ulcerative colitis (UC) (5.3% versus 22.9%). However, sex and age at diagnosis were unassociated with the adverse events of 5-ASA. rs13898676 [odds ratio (OR), 20.33; 95% confidence interval (CI), 5.69-72.67; p = 3.57 × e-6], rs12681590 (OR, 7.35; 95% CI, 2.85-19.00; p = 3.78 × e-5), rs10967320 (OR, 4.51; 95% CI, 2.18-9.31; p = 4.72 × e-5), and rs78726924 (OR, 3.54; 95% CI, 1.69-7.40; p = 7.96 × e-5) were genetic biomarkers predicting 5-ASA-induced severe adverse events in patients with IBD.

Conclusion

The adverse events of 5-ASA were more common in patients with UC than those with CD in our study. We found that novel rs13898676 nearby WSB2 was the most significant genetic locus contributing to 5-ASA's adverse event risk.

Updates on conventional therapies for inflammatory bowel diseases: 5-aminosalicylates, corticosteroids, immunomodulators, and anti-TNF-α

The incidence and prevalence of inflammatory bowel diseases (IBDs) are rapidly increasing worldwide. IBDs are considered an emerging problem not only in Western countries but also in developing counties. The relapses and complications of active IBD mandate various medications. Nevertheless, hospitalization, emergency room visits, or surgery may be required, resulting in a socioeconomic burden. Great advances have been made in the development of new therapeutic options for IBD to achieve induction and maintenance remission. Nevertheless, conventional therapy is still the mainstay in the treatment of IBD. This review article provides an update on recent advances in conventional therapies, including 5-aminosalicylates, corticosteroids, immunomodulators, and anti-tumor necrosis factor-α agents to treat IBD.

Importance of NUDT15 Polymorphisms in Thiopurine Treatments

Thiopurines, mercaptopurine, and azathioprine are used as immunosuppressants in the treatments of inflammatory bowel disease, rheumatoid arthritis, and organ transplantation and as chemotherapeutic drugs for the treatment of acute leukemia and chronic myeloid leukemia. This drug class sometimes causes severe adverse reactions, including bone marrow suppression and hair loss. Genetic polymorphisms of the metabolizing enzyme thiopurine S-methyltransferase have been used for predicting these reactions in Caucasians, but these allele frequencies are less frequently observed in Asian populations. Recently, nudix hydrolase 15 (NUDT15) polymorphisms have been shown to play an important role in thiopurine-induced adverse reactions in Asians. In this review, we summarize the NUDT15 studies, mainly in Asian countries, and their implementation in several countries.

Risk factors and prognostic value of acute severe lower gastrointestinal bleeding in Crohn’s disease

BACKGROUND

Acute severe lower gastrointestinal bleeding (LGIB) is an uncommon but challenging complication of Crohn’s disease (CD).

AIM

To identify the predictors of acute severe LGIB and to evaluate the impact of acute severe LGIB on the subsequent clinical course in CD patients.

METHODS

A retrospective inception cohort study was conducted in 75 CD patients with acute severe LGIB and 1359 CD patients without acute severe LGIB who were diagnosed between February 1991 and November 2019 at Asan Medical Center, a tertiary university hospital in Korea. Multivariable analysis with Cox proportional hazard regression was performed to identify the risk factors for acute severe LGIB. A matched analysis using 72 patients with bleeding and 267 matched patients without within the cohort was also conducted to investigate whether acute severe LGIB is a predictor of clinical outcomes of CD.

RESULTS

Multivariable Cox regression analysis revealed that early use of thiopurines [hazard ratio (HR): 0.23, 95% confidence interval (CI): 0.12-0.48; P < 0.001] and female sex (HR: 0.51, 95%CI: 0.27-0.94; P = 0.031) were significantly associated with a lower risk of acute severe LGIB. The cumulative risks of behavioral progression and intestinal resection were not significantly different between the two matched groups (P = 0.139 and P = 0.769, respectively). The hospitalization rate was higher in the bleeding group than in the matched non-bleeding group (22.1/100 vs 13.2/100 patient-years; P = 0.012). However, if hospitalizations due to bleeding episodes were excluded from the analysis, the hospitalization rate was not significantly different between the bleeding group and the matched non-bleeding group (14.5/100 vs 13.2/100 patient-years; P = 0.631).

CONCLUSION

Early use of thiopurines may reduce the risk of acute severe LGIB. History of acute severe LGIB may not have a significant prognostic value in patients with CD.