Association of Genetic Variants in NUDT15 With Thiopurine-Induced Myelosuppression in Patients With Inflammatory Bowel Disease.

Importance: Use of thiopurines may be limited by myelosuppression. TPMT pharmacogenetic testing identifies only 25% of at-risk patients of European ancestry. Among patients of East Asian ancestry, NUDT15 variants are associated with thiopurine-induced myelosuppression (TIM). Objective: To identify genetic variants associated with TIM among patients of European ancestry with inflammatory bowel disease (IBD). Design, Setting, and Participants: Case-control study of 491 patients affected by TIM and 679 thiopurine-tolerant unaffected patients who were recruited from 89 international sites between March 2012 and November 2015. Genome-wide association studies (GWAS) and exome-wide association studies (EWAS) were conducted in patients of European ancestry. The replication cohort comprised 73 patients affected by TIM and 840 thiopurine-tolerant unaffected patients. Exposures: Genetic variants associated with TIM. Main Outcomes and Measures: Thiopurine-induced myelosuppression, defined as a decline in absolute white blood cell count to 2.5 × 109/L or less or a decline in absolute neutrophil cell count to 1.0 × 109/L or less leading to a dose reduction or drug withdrawal. Results: Among 1077 patients (398 affected and 679 unaffected; median age at IBD diagnosis, 31.0 years [interquartile range, 21.2 to 44.1 years]; 540 [50%] women; 602 [56%] diagnosed as having Crohn disease), 919 (311 affected and 608 unaffected) were included in the GWAS analysis and 961 (328 affected and 633 unaffected) in the EWAS analysis. The GWAS analysis confirmed association of TPMT (chromosome 6, rs11969064) with TIM (30.5% [95/311] affected vs 16.4% [100/608] unaffected patients; odds ratio [OR], 2.3 [95% CI, 1.7 to 3.1], P = 5.2 × 10-9). The EWAS analysis demonstrated an association with an in-frame deletion in NUDT15 (chromosome 13, rs746071566) and TIM (5.8% [19/328] affected vs 0.2% [1/633] unaffected patients; OR, 38.2 [95% CI, 5.1 to 286.1], P = 1.3 × 10-8), which was replicated in a different cohort (2.7% [2/73] affected vs 0.2% [2/840] unaffected patients; OR, 11.8 [95% CI, 1.6 to 85.0], P = .03). Carriage of any of 3 coding NUDT15 variants was associated with an increased risk (OR, 27.3 [95% CI, 9.3 to 116.7], P = 1.1 × 10-7) of TIM, independent of TPMT genotype and thiopurine dose. Conclusions and Relevance: Among patients of European ancestry with IBD, variants in NUDT15 were associated with increased risk of TIM. These findings suggest that NUDT15 genotyping may be considered prior to initiation of thiopurine therapy; however, further study including additional validation in independent cohorts is required.

IL28B genotype is not useful for predicting treatment outcome in Asian chronic hepatitis B patients treated with pegylated interferon-α.

BACKGROUND AND AIM: IL28B genotype predicts response to pegylated interferon (peg-IFN)-based therapy in chronic hepatitis C. However, the utility of IL28B genotyping in chronic hepatitis B (CHB) cohorts treated with peg-IFN is unclear. It was investigated whether IL28B genotype is associated with peg-IFN treatment outcomes in a predominantly Asian CHB cohort. METHODS: This was a retrospective analysis of CHB patients treated with 48 weeks of peg-IFN monotherapy. IL28B genotype (rs12979860) was determined (TaqMan allelic discrimination kit). Baseline hepatitis B virus (HBV)-DNA, alanine aminotransferase, and liver histology were available. The primary end-points were HBV e antigen (HBeAg) seroconversion with HBV-DNA < 2000 IU/mL 24 weeks post-therapy (HBeAg-positive patients) and HBV-DNA < 2000 IU/mL 24 weeks after peg-IFN (HBeAg-negative patients). The association between IL28B genotype and peg-IFN outcomes was analyzed. RESULTS: IL28B genotype was determined for 96 patients. Eighty-eight percent were Asian, 62% were HBeAg positive, and 13% were METAVIR stage F3-4. Median follow-up time was 39.3 months. The majority of patients carried the CC IL28B genotype (84%). IL28B genotype did not differ according to HBeAg status. The primary end-points were achieved in 27% of HBeAg-positive and 61% of HBeAg-negative patients. There was no association between IL28B genotype and the primary end-point in either group. Furthermore, there was no difference in HBeAg loss alone, HBV surface antigen, alanine aminotransferase normalization, or on-treatment HBV-DNA levels according to IL28B genotype. CONCLUSIONS: In the context of a small possible effect size and high frequency in Asian populations, IL28B genotyping is likely to have, at best, limited clinical utility for predicting peg-IFN treatment outcome for CHB patients in the Asia-Pacific region.

Root-cause analyses of missed opportunities for the diagnosis of colorectal cancer in patients with inflammatory bowel disease.

BACKGROUND: Colonoscopic surveillance in patients with inflammatory bowel disease (IBD) leads to earlier detection of colorectal cancer (CRC) and reduces CRC-associated mortality. However, it is limited by poor adherence in practice. AIM: To identify missed opportunities to detect IBD-associated CRC at our hospital METHODS: We undertook root-cause analyses to identify patients with missed opportunities to diagnose IBD-associated CRC. We matched patients with IBD-associated CRC to patients with CRC in the general population to identify differences in staging at diagnosis and clinical outcomes. RESULTS: Compared with the general population, patients with IBD were at increased risk of developing CRC (odds ratio 2.7 [95% CI 1.6-3.9], P < 0.001). The mean incidence of IBD-associated CRC between 1998 and 2019 was 165.4 (IQR 130.4-199.4) per 100 000 patients and has not changed over the last 20 years. Seventy-eight patients had IBD-associated CRC. Forty-two (54%) patients were eligible for CRC surveillance: 12% (5/42) and 10% (4/42) patients were diagnosed with CRC at an appropriately timed or overdue surveillance colonoscopy, respectively. Interval cancers occurred in 14% (6/42) of patients; 64% (27/42) of patients had a missed opportunity for colonoscopic surveillance where root-cause analyses demonstrated that 10/27 (37%) patients known to secondary care had not been offered surveillance. Four (15%) patients had a delayed diagnosis of CRC due to failure to account for previous colonoscopic findings. Seventeen (63%) patients were managed by primary care including seven patients discharged from secondary care without a surveillance plan. Matched case-control analysis did not show significant differences in cancer staging or 10-year survival outcomes. CONCLUSION: The incidence of IBD-associated CRC has remained static. Two-thirds of patients eligible for colonoscopic surveillance had missed opportunities to diagnose CRC. Surveillance programmes without comprehensive and fully integrated recall systems across primary and secondary care are set to fail.

Primary care faecal calprotectin testing in children with suspected inflammatory bowel disease: a diagnostic accuracy study.

OBJECTIVE: To determine the diagnostic accuracy of calprotectin to diagnose inflammatory bowel disease (IBD) in children in whom general practitioners (GPs) suspected IBD. DESIGN: Prospective observational cohort study of a new calprotectin-based primary care referral pathway. SETTING: 48 GP practices and gastroenterology secondary care services at the Royal Devon and Exeter NHS Foundation Trust in the South-West of England, UK. PATIENTS: 195 children aged between 4 and 18 years referred on the pathway between January 2014 and August 2017 for investigation of gastrointestinal symptoms were included. INTERVENTIONS: Primary-care-driven faecal calprotectin testing. Primary and secondary care records over 12 months from the point of calprotectin testing were used as the reference standard. MAIN OUTCOME MEASURES: Diagnostic accuracy of calprotectin testing to detect IBD. RESULTS: 7% (13/195) tested patients were diagnosed with IBD. Using our prespecified cut-off of 100 µg/g, calprotectin had a diagnostic accuracy of 91% (95% CI 86% to 95%) with a sensitivity for distinguishing IBD from non-IBD of 100% (95% CI 75% to 100%), a specificity of 91% (95% CI 85% to 94%), a positive predictive value of 43% (95% CI 25% to 63%) and a negative predictive value of 100% (95% CI 98% to 100%). Calprotectin testing had no effect on the time to diagnosis, but a negative test contributed to saved referrals and was associated with fewer diagnostic tests in secondary care. CONCLUSIONS: Calprotectin testing of children with suspected IBD in primary care accurately distinguishes IBD from a functional gut disorder, reduces secondary care referrals and associated diagnostic healthcare utilisation.

Clinical Features and Genetic Risk of Demyelination Following Anti-TNF Treatment.

BACKGROUND: Anti-TNF exposure has been linked to demyelination events. We sought to describe the clinical features of demyelination events following anti-TNF treatment and to test whether affected patients were genetically predisposed to multiple sclerosis [MS]. METHODS: We conducted a case-control study to describe the clinical features of demyelination events following anti-TNF exposure. We compared genetic risk scores [GRS], calculated using carriage of 43 susceptibility loci for MS, in 48 cases with 1219 patients exposed to anti-TNF who did not develop demyelination. RESULTS: Overall, 39 [74%] cases were female. The median age [range] of patients at time of demyelination was 41.5 years [20.7-63.2]. The median duration of anti-TNF treatment was 21.3 months [0.5-99.4] and 19 [36%] patients were receiving concomitant immunomodulators. Most patients had central demyelination affecting the brain, spinal cord, or both. Complete recovery was reported in 12 [23%] patients after a median time of 6.8 months [0.1-28.7]. After 33.0 months of follow-up, partial recovery was observed in 29 [55%] patients, relapsing and remitting episodes in nine [17%], progressive symptoms in three [6%]: two [4%] patients were diagnosed with MS. There was no significant difference between MS GRS scores in cases (mean -3.5 × 10-4, standard deviation [SD] 0.0039) and controls [mean -1.1 × 10-3, SD 0.0042] [p = 0.23]. CONCLUSIONS: Patients who experienced demyelination events following anti-TNF exposure were more likely female, less frequently treated with an immunomodulator, and had a similar genetic risk to anti-TNF exposed controls who did not experience demyelination events. Large prospective studies with pre-treatment neuroimaging are required to identify genetic susceptibility loci.

Predictors of anti-TNF treatment failure in anti-TNF-naive patients with active luminal Crohn's disease: a prospective, multicentre, cohort study.

BACKGROUND: Anti-TNF drugs are effective treatments for the management of Crohn's disease but treatment failure is common. We aimed to identify clinical and pharmacokinetic factors that predict primary non-response at week 14 after starting treatment, non-remission at week 54, and adverse events leading to drug withdrawal. METHODS: The personalised anti-TNF therapy in Crohn's disease study (PANTS) is a prospective observational UK-wide study. We enrolled anti-TNF-naive patients (aged ≥6 years) with active luminal Crohn's disease at the time of first exposure to infliximab or adalimumab between March 7, 2013, and July 15, 2016. Patients were evaluated for 12 months or until drug withdrawal. Demographic data, smoking status, age at diagnosis, disease duration, location, and behaviour, previous medical and drug history, and previous Crohn's disease-related surgeries were recorded at baseline. At every visit, disease activity score, weight, therapy, and adverse events were recorded; drug and total anti-drug antibody concentrations were also measured. Treatment failure endpoints were primary non-response at week 14, non-remission at week 54, and adverse events leading to drug withdrawal. We used regression analyses to identify which factors were associated with treatment failure. FINDINGS: We enrolled 955 patients treated with infliximab (753 with originator; 202 with biosimilar) and 655 treated with adalimumab. Primary non-response occurred in 295 (23·8%, 95% CI 21·4-26·2) of 1241 patients who were assessable at week 14. Non-remission at week 54 occurred in 764 (63·1%, 60·3-65·8) of 1211 patients who were assessable, and adverse events curtailed treatment in 126 (7·8%, 6·6-9·2) of 1610 patients. In multivariable analysis, the only factor independently associated with primary non-response was low drug concentration at week 14 (infliximab: odds ratio 0·35 [95% CI 0·20-0·62], p=0·00038; adalimumab: 0·13 [0·06-0·28], p<0·0001); the optimal week 14 drug concentrations associated with remission at both week 14 and week 54 were 7 mg/L for infliximab and 12 mg/L for adalimumab. Continuing standard dosing regimens after primary non-response was rarely helpful; only 14 (12·4% [95% CI 6·9-19·9]) of 113 patients entered remission by week 54. Similarly, week 14 drug concentration was also independently associated with non-remission at week 54 (0·29 [0·16-0·52] for infliximab; 0·03 [0·01-0·12] for adalimumab; p<0·0001 for both). The proportion of patients who developed anti-drug antibodies (immunogenicity) was 62·8% (95% CI 59·0-66·3) for infliximab and 28·5% (24·0-32·7) for adalimumab. For both drugs, suboptimal week 14 drug concentrations predicted immunogenicity, and the development of anti-drug antibodies predicted subsequent low drug concentrations. Combination immunomodulator (thiopurine or methotrexate) therapy mitigated the risk of developing anti-drug antibodies (hazard ratio 0·39 [95% CI 0·32-0·46] for infliximab; 0·44 [0·31-0·64] for adalimumab; p<0·0001 for both). For infliximab, multivariable analysis of immunododulator use, and week 14 drug and anti-drug antibody concentrations showed an independent effect of immunomodulator use on week 54 non-remission (odds ratio 0·56 [95% CI 0·38-0·83], p=0·004). INTERPRETATION: Anti-TNF treatment failure is common and is predicted by low drug concentrations, mediated in part by immunogenicity. Clinical trials are required to investigate whether personalised induction regimens and treatment-to-target dose intensification improve outcomes. FUNDING: Guts UK, Crohn's and Colitis UK, Cure Crohn's Colitis, AbbVie, Merck Sharp and Dohme, Napp Pharmaceuticals, Pfizer, and Celltrion.

Reversal of end-stage heart failure in juvenile hemochromatosis with iron chelation therapy: a case report.

BACKGROUND: Juvenile hemochromatosis is the most severe form of iron overloading phenotype. Although rare, it should be suspected in patients who present with hypogonadotropic hypogonadism, diabetes mellitus, or cardiomyopathy without a clear cause. CASE PRESENTATION: A young Serbian male presenting with end-stage heart failure was referred for extracorporeal membrane oxygenation. An endomyocardial biopsy revealed cytoplasmic iron deposits in myocytes. His condition was stabilized with biventricular assist devices and he was listed for heart transplantation. Iron chelation therapy was commenced and resulted in rapid removal of iron burden. Serial outpatient echocardiograms demonstrated myocardial recovery such that a successful biventricular assist device explant occurred 131 days after initial implant. Targeted gene sequencing revealed a loss-of-function mutation within the HJV gene, which is consistent with juvenile hemochromatosis. CONCLUSIONS: This rare case of a patient with juvenile hemochromatosis associated with a HJV mutation provides histologic evidence documenting the reversal of associated end-stage heart failure, requiring emergent mechanical circulatory support, with iron chelation therapy.