Use of Thiopurines in Inflammatory Bowel Disease: A Consensus Statement by the Korean Association for the Study of Intestinal Diseases (KASID)

NUDT15 polymorphisms are better than thiopurine S-methyltransferase as predictor of risk for thiopurine-induced leukopenia in Chinese patients with Crohn's disease

BACKGROUND

Thiopurine-induced leukopenia is the most common dangerous adverse event in Asians. NUDT15 R139C was recently proposed to be a promising biomarker for leukopenia with thiopurine therapy in Asians, but this has not been replicated in the Chinese population.

AIM

To investigate the influence of NUDT15 R139C, thiopurine S-methyltransferase (TPMT), 6-TGN and 6-MMPR on thiopurine-induced leukopenia in Chinese patients with Crohn's disease.

METHODS

Clinical and epidemiological characteristics were reviewed from medical records. NUDT15 R139C and TPMT were genotyped. 6-TGN/6-MMPR concentrations were measured with high-performance liquid chromatography (HPLC).

RESULTS

A total of 253 patients were included, 65 (25.7%) of whom experienced leukopenia. The median follow-up with thiopurine treatment was 38.0 weeks (range, 1-192 weeks). NUDT15 R139C was strongly associated with the incidence of leukopenia (70.2% mutation vs. 12.8% wild type; P=8.61×10^-19 ; odds ratio, 10.80; 95% CI, 5.89-19.83). However, TPMT genotype was not found to be correlated with the incidence of leukopenia (P = 0.44). In subgroup of NUDT15 wild type, there was significant difference of 6TGN concentration between patients with and without leukopenia (413.0 (174.2-831.4) vs. 279.7 (77.3-666.9) pmol/8 × 10⁸ RBC, P = 0.0055). In contrast, no association was found in patients with NUDT15 R139C variant alleles (P = 0.26). 6-MMPR was not correlated with leukopenia (P = 0.84).

CONCLUSIONS

In Chinese patients, it is strongly recommended to detect NUDT15 genotype rather than TPMT before initiating thiopurine drugs. 6TGN concentration should be routinely monitored in CD patients with NUDT15 wild type. As for CT genotype, starting at low dose and careful monitoring for leukopenia and 6TGN levels is recommended.

Measurement of red blood cell 6-thioguanine nucleotide is beneficial in azathioprine maintenance therapy of Chinese Crohn's disease patients

OBJECTIVE

It remains controversial whether 6-thioguanine nucleotide (6-TGN)-based dose adjusting can be beneficial in azathioprine (AZA) therapy. This study is designed to assess the role of 6-TGN concentrations in maintaining clinical remission in Chinese patients with Crohn's disease (CD).

MATERIAL AND METHOD

We performed a prospective observational study and collected data of CD patients in the First Affiliated Hospital of Anhui Medical University from June 2013 to April 2014. Demographic material, CD activity index, 6-TGN concentration, and laboratory tests were recorded at baseline and at each visit. In addition, 6-TGN was measured when drug adverse effects occurred. All patients achieved maintenance stage were administered a stable AZA dose at least 3 months before enrollment and were followed up at least 12 months. Thiopurine S-methyltransferase (TPMT) genotype was measured before AZA treatment.

RESULTS

Sixty-nine patients receiving maintenance therapy were analyzed. A positive correlation was found between 6-TGN levels and AZA dose (r = 0.258, p = 0.032). The mean 6-TGN concentration was 302.06 ± 115.84 in the remission group vs. 264.94 ± 164.53 pmol/8 × 10(8) RBC in those with active disease (t = 0.847, p = 0.40), and 197.74 ± 66.54 pmol/8 × 10(8) RBC in patients who relapsed vs. 310.26 ± 122.38 pmol/8 × 10(8) RBC for those in sustained remission (t= -2.541, p = 0.013). In the leukopenia group, the 6-TGN concentration was 469.11 ± 115.53 pmol/8 × 10(8) RBC vs. 257.31 ± 83.74 pmol/8 × 10(8) RBC in the non-leukopenia group (t = 7.622, p < 0.001). There was a significant negative correlation between leukocyte count and 6-TGN concentration (r= -0.326, p = 0.006).

CONCLUSIONS

6-TGN measurement is a helpful method of preventing disease relapse and avoiding leukopenia in individual azathioprine maintenance therapy.

Long-Term Outcomes of Infliximab Treatment in 582 Korean Patients with Crohn's Disease: A Hospital-Based Cohort Study

BACKGROUND AND AIMS

To date, no large-scale studies have evaluated long-term outcomes of infliximab (IFX) treatment in Korean patients with Crohn's disease (CD).

METHODS

We analyzed long-term clinical responses to IFX in 582 Korean CD patients who received scheduled IFX treatments at Asan Medical Center. Clinical responses were defined as maintaining IFX without major abdominal surgery (MAS) or dose intensification.

RESULTS

Between February 2002 and July 2015, a total of 11,990 IFX infusions were administered to 582 Korean patients with CD over a median period of 36 months. At the end of follow-up, 316 (54.3 %) were still receiving IFX without MAS (71 patients, 12.2 %) or dose intensification (86 patients, 14.8 %). IFX was stopped in 109 (18.7 %) patients because of a loss of response (48 patients, 8.2 %), adverse events (30 patients, 5.2 %), or patient preferences or problems with reimbursement (31 patients, 5.3 %). The cumulative survival for maintenance of IFX without MAS or dose intensification was 89.0, 75.9, 68.3, and 50.8 % at 1, 2, 3, and 5 years, respectively. Multivariate regression analysis identified older age at the initiation of IFX (≥40 years, P = 0.006) and a longer disease duration (≥3 years, P = 0.020) as independent positive predictors of a poorer response to IFX.

CONCLUSIONS

The long-term efficacy of IFX in a large, real-life cohort of Korean patients with CD appears to be similar to that in previously published Western studies. Our findings support the early use of IFX to obtain better clinical outcomes.

Change in the diagnosis of inflammatory bowel disease: a hospital-based cohort study from Korea

BACKGROUND/AIMS

Accurately diagnosing inflammatory bowel disease (IBD) remains a challenge, but is crucial for providing proper management for affected patients. The aim of the present study was to evaluate the frequency of change in diagnosis in Korean patients who were referred to our institution with a diagnosis of IBD.

METHODS

We enrolled 1,444 patients diagnosed with ulcerative colitis (UC) and 1,452 diagnosed with Crohn's disease (CD), who had been referred to the Asan Medical Center between January 2010 and December 2014. These patients were assessed and subsequently classified as having UC, CD, indeterminate colitis, possible IBD, or non-IBD.

RESULTS

During a median follow-up of 15.9 months, 400 of the 2,896 patients (13.8%) analyzed in this study experienced a change in diagnosis. A change in diagnosis from UC to CD, or vice-versa, was made in 24 of 1,444 patients (1.7%) and 23 of 1,452 patients (1.6%), respectively. A change to a non-IBD diagnosis was the most common modification; 7.5% (108 of 1444) and 12.7% (184 of 1452) of the patients with a referral diagnosis of UC and CD, respectively, were reclassified as having non-IBD. Among the 292 patients who were ultimately determined not to have IBD, 135 (55 UC and 80 CD cases) had received IBD-related medication.

CONCLUSIONS

There are diagnostic uncertainties and difficulties in relation to IBD. Therefore, precise assessment and systematic follow-up are essential in the management of this condition.

Six Cases of Lung Injury Following Anti-tumour Necrosis Factor Therapy for Inflammatory Bowel Disease

BACKGROUND AND AIMS

Limited data are available regarding the pulmonary toxicity of anti-tumour necrosis factor (anti-TNF) therapy for inflammatory bowel disease (IBD).

METHODS

We retrospectively searched the IBD registry of Asan Medical Center in order to identify patients with lung injury following anti-TNF therapy.

RESULTS

Among 1002 patients who were treated using anti-TNF therapy, six cases (0.6%) of anti-TNF-induced lung injury (ATILI) were identified. ATILI was observed soon after the beginning of anti-TNF therapy (two to four doses of anti-TNF). All of these patients experienced improvements in their respiratory symptoms and radiographic findings once the anti-TNF therapy was discontinued. One patient who suffered ATILI following adalimumab was switched to subsequent infliximab and was without recurrence of ATILI.

CONCLUSION

Clinicians should be vigilant regarding the possibility of ATILI in IBD patients treated with anti-TNF agents.