The use of thiopurines for the treatment of inflammatory bowel diseases in clinical practice

Landscape of TPMT and NUDT15 Pharmacogenetic Variation in a Cohort of Canadian Pediatric Inflammatory Bowel Disease Patients

BACKGROUND

Patients with inflammatory bowel disease (IBD) exhibit considerable interindividual variability in medication response, highlighting the need for precision medicine approaches to optimize and tailor treatment. Pharmacogenetics (PGx) offers the ability to individualize dosing by examining genetic factors underlying the metabolism of medications such as thiopurines. Pharmacogenetic testing can identify individuals who may be at risk for thiopurine dose-dependent adverse reactions including myelosuppression. We aimed to evaluate PGx variation in genes supported by clinical guidelines that inform dosing of thiopurines and characterize differences in the distribution of actionable PGx variation among diverse ancestral groups.

METHODS

Pharmacogenetic variation in TPMT and NUDT15 was captured by genome-wide genotyping of 1083 pediatric IBD patients from a diverse Canadian cohort. Genetic ancestry was inferred using principal component analysis. The proportion of PGx variation and associated metabolizer status phenotypes was compared across 5 genetic ancestral groups within the cohort (Admixed American, African, East Asian, European, and South Asian) and to prior global estimates from corresponding populations.

RESULTS

Collectively, 11% of the cohort was categorized as intermediate or poor metabolizers of thiopurines, which would warrant a significant dose reduction or selection of alternate therapy. Clinically actionable variation in TPMT was more prevalent in participants of European and Admixed American/Latino ancestry (8.7% and 7.5%, respectively), whereas variation in NUDT15 was more prevalent in participants of East Asian and Admixed American/Latino ancestry (16% and 15% respectively).

CONCLUSIONS

These findings demonstrate the considerable interpopulation variability in PGx variation underlying thiopurine metabolism, which should be factored into testing diverse patient populations.

Differences in the risk of clinical failure between thiopurine and methotrexate in bio-naïve patients with Crohn's disease: a Korean nationwide population-based study

Background

Although immunomodulators are widely prescribed in patients with Crohn's disease (CD), it is unclear whether there is a difference in treatment outcomes between thiopurines and methotrexate (MTX).

Objective

To compare the risk of clinical failure between thiopurines and MTX in bio-naïve patients with CD.

Design

Nationwide, population-based study.

Methods

We used claims data from the Korean National Health Insurance Service. After inverse probability of treatment weighting, logistic regression and Cox proportional hazard analyses were used to evaluate the risk of clinical failure in bio-naïve patients with CD treated with thiopurine (thiopurine group) or MTX (MTX group).

Results

Overall, 10,296 adult and pediatric patients with CD [9912 (96.3%) and 384 (3.7%) in the thiopurine and MTX groups, respectively] were included. The odds ratios (ORs) of failure to induce remission were significantly higher in the MTX group than in the thiopurine group [adjusted OR (aOR), 1.115; 95% confidence interval (CI), 1.045-1.190; p = 0.001]. However, the opposite result was observed only in patients without concomitant steroid use: the MTX group had a lower risk of induction failure than the thiopurine group (aOR, 0.740; 95% CI, 0.673-0.813; p < 0.001). The risk of overall maintenance failure was higher in the MTX group than in the thiopurine group [adjusted hazard ratio (aHR), 1.117; 95% CI, 1.047-1.191; p = 0.001]. The risk of overall maintenance failure was higher in the standard-dose MTX group than in the low-dose MTX group (aHR, 1.296; 95% CI, 1.134-1.480; p < 0.001). There was no significant difference in the risk of maintenance failure according to the administration route of MTX.

Conclusion

Thiopurine is more effective than MTX in inducing and maintaining remission in bio-naïve patients with CD; however, the concomitant use of steroids influences inducing remission.

Comparing Myelosuppression Frequency in Indian Inflammatory Bowel Disease Patients: A Randomized Trial of Full Dose Versus Gradual Escalation of Thiopurines

INTRODUCTION

We aimed to compare the frequency of myelosuppression in patients initiating azathioprine (AZA) at full dose versus those undergoing gradual dose escalation.

METHODS

Forty patients with inflammatory bowel disease were recruited over one year and randomized into two groups of 20. Group A initiated AZA at a full dose of 2 mg/kg, while group B started at 1 mg/kg with subsequent dose increases at regular intervals.

RESULTS

Seventeen patients from each group were included in the final analysis. During follow-up, two patients (11.8%) from group A and four patients (23.5%) from group B experienced relapses (p=0.65). Myelosuppression occurred in two patients (11.8%) from each group. Absolute neutrophil counts in group A tended to have lower median values than those in group B, particularly four weeks after AZA initiation. Univariate analysis identified serum proteins, albumin, and bilirubin as significantly associated with leukopenia, but these factors were not significant according to multivariate analysis.

CONCLUSIONS

The incidence of myelosuppression was similar between the groups. Patients with full-dose initiation of AZA had numerically fewer relapses during the follow-up period.

Feasibility of Reduced Clinical Monitoring in Patients with Inflammatory Bowel Disease Treated with Thiopurine Therapy

BACKGROUND

Outpatient visits and laboratory assessments are routinely scheduled every 3 to 4 months in thiopurine-treated patients with inflammatory bowel disease (IBD) to timely detect thiopurine-related adverse events (AEs). AEs that require therapy adjustment beyond 12 months of treatment are rare.

AIM AND METHODS

This single-center prospective cohort study evaluated the safety of a reduced 6-monthly monitoring strategy in steroid-free patients with quiescent IBD on stable dose of azathioprine, mercaptopurine, or thioguanine monotherapy. The primary outcome was thiopurine-related AEs requiring therapy adjustments during a follow-up period of 24 months. Secondary outcomes included all AEs including laboratory toxicity, disease flares until 12 months, and the net monetary benefit from this strategy concerning IBD-related health care use.

RESULTS

We enrolled 85 patients with IBD (median age 42 years, 61% Crohn's disease, 62% female), with a median disease duration of 12.5 years and median thiopurine treatment duration of 6.7 years. During follow-up, 3 patients (4%) ceased thiopurines due to AEs: recurrent infections, non-melanoma skin cancer, and gastrointestinal complaints (nausea, vomiting). At 12 months, 25 laboratory toxicities were observed (including 13% myelotoxicity, 17% hepatotoxicity); none required therapy adjustments and all were transient. A reduced monitoring strategy had a net benefit of €136 per patient.

CONCLUSION

Three patients (4%) ceased thiopurine therapy due to thiopurine-related AEs, while no laboratory toxicity required therapy adjustments. Monitoring frequency of every 6 months seems feasible in patients with stable IBD on long-term (median duration > 6 years) maintenance thiopurine therapy and may contribute to reduced patient-burden and health care costs.

Classic drugs in the time of new drugs: real-world, long-term outcomes of thiopurine monotherapy in 1016 patients with inflammatory bowel disease

BACKGROUND

Thiopurines remain recommended as maintenance therapy in patients with inflammatory bowel disease (IBD). Despite their widespread use, long-term effectiveness data are sparse and safety is an increasingly debated topic which thwarts proper delineation in the current IBD treatment algorithm.

AIMS

To document effectiveness and safety of thiopurine monotherapy in patients with IBD, using the population-based IBD South-Limburg (IBDSL) cohort METHODS: All patients starting thiopurine monotherapy as maintenance between 1991 and 2014 were included. Therapy was defined as effective if there was no escalation to biologicals, no course of corticosteroids, no surgery and no hospitalisation for active disease during treatment. Long-term effectiveness was assessed by adjusting for differences in follow-up using Kaplan-Meier analyses. Mid- to long-term safety regarding cancer incidence and clinically relevant liver disease was documented.

RESULTS

In total, 1016 patients (643 Crohn's disease [CD]; 373 ulcerative colitis [UC]) received thiopurine monotherapy at a median of 15.2 (Q1-Q3 4.2-48.5) months after diagnosis. During follow-up, effectiveness rates at 1, 5 and 10 years were 64%, 45%, 32%, respectively, in CD and and 66%, 41%, 36%, respectively in UC. No statistically significant differences in effectiveness were observed after stratification for era of initiation (pre-biological vs biological, CD: p = 0.56; UC: p = 0.43). Sixteen non-melanoma skin cancers (incidence rate [IR] 3.33/1000 PY), five lymphomas (IR 1.04/1000 PY) and one urinary tract cancer (IR 0.21/1000 PY) were recorded. Two cases of portal hypertension were identified.

CONCLUSION

In real-world practice, thiopurine monotherapy remains effective, safe and durable for patients with CD or UC, including in the era of biologics.

TPMT and NUDT15 polymorphisms in thiopurine induced leucopenia in inflammatory bowel disease: a prospective study from India

BACKGROUND

Polymorphisms in thiopurine methyltransferase (TPMT) and Nudix hydrolase-15 (NUDT15) have been implicated as the predominant cause of thiopurine induced leukopenia in the Western countries and East Asia respectively. Exact role of these polymorphisms in South Asian population with inflammatory bowel disease (IBD) is uncertain.

METHODS

We included consecutive patients with IBD who were initiated on thiopurines at a center in North India. The dosage of thiopurines was titrated using regular monitoring of hemogram and liver function tests. Three TPMT polymorphisms (c.238 G > C, c.460 G > A, and c.719A > G) and one NUDT15 polymorphism (c.415 C > T) were assessed. Comparison regarding incidence of leukopenia and maximum tolerated thiopurine dosage was performed between those with wild polymorphism and those with TPMT and NUDT15 polymorphisms, respectively.

RESULTS

Of the 119 patients (61 males, mean age 36.8 ± 13.5 years), 105 (88.2%) had ulcerative colitis and 14 (11.8%) had Crohn's disease. Leukopenia was noted in 33 (27.7%), gastrointestinal intolerance in 5 (4.2%) and pancreatitis in 2 (1.6%). TPMT polymorphisms were detected amongst five patients of whom 1 developed leukopenia. NUDT15 polymorphism was noted in 13 patients of whom 7 had leukopenia. The odds of developing leukopenia in TPMT polymorphism were non-significant (0.77, 95% CI:0.0822 to 7.2134, P = 0.819) but were significantly higher in those with NUDT15 polymorphism (3.5933, 1.1041 to 11.6951, P value: = 0.0336).

CONCLUSION

NUDT15 polymorphism was more frequent than TPMT polymorphisms and was associated with thiopurine induced leukopenia. However, the tested polymorphisms account for only 24.2% of the risk of thiopurine induced leukopenia.

Pharmacotherapy of inflammatory bowel diseases: efficacy performance and safety management

Treatment of inflammatory bowel diseases IBD (Crohns disease, ulcerative colitis) is aimed at achieving clinical, endoscopic and histological remission, minimizing surgical complications, and ensuring a normal quality of life. However, the use of medical treatment is potentially associated with various adverse events, among which infectious complications, malignant neoplasms, as well as myelotoxicity, hepatotoxicity, skin lesions and others. The risk of side effects depends on the type of drug therapy (5-aminosalicylates, thiopurines, biologicals, etc.), the duration of treatment, the presence of extra-intestinal manifestations, etc. The article provides an overview of data on both the effectiveness and frequency of various side effects of the main classes of drugs in IBD, presents methods of investigation which can predict the effectiveness and development of side effects, the implementation of which can be considered as a variant of personalized therapy in IBD.

Thiopurine monotherapy is effective in ulcerative colitis but significantly less so in Crohn's disease: long-term outcomes for 11 928 patients in the UK inflammatory bowel disease bioresource

OBJECTIVE

Thiopurines are widely used as maintenance therapy in inflammatory bowel disease (IBD) but the evidence base for their use is sparse and their role increasingly questioned. Using the largest series reported to date, we assessed the long-term effectiveness of thiopurines in ulcerative colitis (UC) and Crohn's disease (CD), including their impact on need for surgery.

DESIGN

Outcomes were assessed in 11 928 patients (4968 UC, 6960 CD) in the UK IBD BioResource initiated on thiopurine monotherapy with the intention of maintaining medically induced remission. Effectiveness was assessed retrospectively using patient-level data and a definition that required avoidance of escalation to biological therapy or surgery while on thiopurines. Analyses included overall effectiveness, time-to-event analysis for treatment escalation and comparison of surgery rates in patients tolerant or intolerant of thiopurines.

RESULTS

Using 68 132 patient-years of exposure, thiopurine monotherapy appeared effective for the duration of treatment in 2617/4968 (52.7%) patients with UC compared with 2378/6960 (34.2%) patients with CD (p<0.0001). This difference was corroborated in a multivariable analysis: after adjusting for variables including treatment era, thiopurine monotherapy was less effective in CD than UC (OR 0.47, 95% CI 0.43 to 0.51, p<0.0001). Thiopurine intolerance was associated with increased risk of surgery in UC (HR 2.44, p<0.0001); with a more modest impact on need for surgery in CD (HR=1.23, p=0.0015).

CONCLUSION

Thiopurine monotherapy is an effective long-term treatment for UC but significantly less effective in CD.

Personalized Medicine of Monoclonal Antibodies in Inflammatory Bowel Disease: Pharmacogenetics, Therapeutic Drug Monitoring, and Beyond

The pharmacotherapy of inflammatory bowel diseases (Crohn’s disease and ulcerative colitis) has experienced significant progress with the advent of monoclonal antibodies (mABs). As therapeutic proteins, mABs display peculiar pharmacokinetic characteristics that differentiate them from chemical drugs, such as aminosalicylates, antimetabolites (i.e., azathioprine, 6-mercaptopurine, and methotrexate), and immunosuppressants (corticosteroids and cyclosporine). However, clinical trials have demonstrated that biologic agents may suffer from a pharmacokinetic variability that could influence the desired clinical outcome, beyond primary resistance phenomena. Therefore, therapeutic drug monitoring (TDM) protocols have been elaborated and applied to adaptation drug doses according to the desired plasma concentrations of mABs. This activity is aimed at maximizing the beneficial effects of mABs while sparing patients from toxicities. However, some aspects of TDM are still under discussion, including time-changing therapeutic ranges, proactive and reactive approaches, the performance and availability of instrumental platforms, the widely varying individual characteristics of patients, the severity of the disease, and the coadministration of immunomodulatory drugs. Facing these issues, personalized medicine in IBD may benefit from a combined approach, made by TDM protocols and pharmacogenetic analyses in a timeline that necessarily considers the frailty of patients, the chronic administration of drugs, and the possible worsening of the disease. Therefore, the present review presents and discusses the activities of TDM protocols using mABs in light of the most recent results, with special attention on the integration of other actions aimed at exploiting the most effective and safe therapeutic effects of drugs prescribed in IBD patients.

Exclusive enteral nutrition is effective and feasible as primary induction and re-induction therapy in Asian children with Crohn's disease

AIM

We aimed to ascertain the efficacy and feasibility of exclusive enteral nutrition (EEN) as an induction and re-induction therapy in Asian children with Crohn's disease (CD).

METHODS

All children diagnosed with CD between 1995 and 2019 were reviewed. Response to induction was compared between EEN and standard immunosuppression (IS) using Paediatric Crohn's Disease Activity Index, growth failure, perianal disease and extra-intestinal manifestations. Two study groups were analysed: (i) primary induction and (ii) re-induction for relapses.

RESULTS

Twenty-nine children (mean age (± standard deviation) at diagnosis 9.4 ± 8.5 years old, ileo-colonic 35%, non-stricturing 79%) were studied. At primary induction (group 1; n = 18), no difference was observed in remission rates (9/13 vs. 5/5; P = 0.278), efficacy for improving growth failure (6/8 vs. 0/1; P > 0.999), perianal disease (4/6 vs. 0/2; P > 0.999) and extra-intestinal manifestations (2/2 vs. 0/0; P > 0.999) with EEN or standard IS. Group 2 (n = 38 relapses), no difference was observed in remission rates (16/19 vs. 15/19, P > 0.999), growth failure (0/7 vs. 4/14; P = 0.328), perianal disease (1/10 vs. 7/7; P > 0.999) and extra-intestinal manifestations (0/0 vs. 1/1; P > 0.999) with EEN or standard IS. Both treatment modalities were equally effective as re-induction in relapses in patients previously treated with EEN (P = 0.191).

CONCLUSION

As compared to standard IS, EEN was equally effective in primary induction and re-induction for relapse in Asian children with CD and can be repeatedly used for recurrent relapses.

Inflammatory Bowel Disease: The Emergence of New Trends in Lifestyle and Nanomedicine as the Modern Tool for Pharmacotherapy

The human intestine, which harbors trillions of symbiotic microorganisms, may enter into dysbiosis when exposed to a genetic defect or environmental stress. The naissance of chronic inflammation due to the battle of the immune system with the trespassing gut bacteria leads to the rise of inflammatory bowel disease (IBD). Though the genes behind the scenes and their link to the disease are still unclear, the onset of IBD occurs in young adults and has expanded from the Western world into the newly industrialized countries. Conventional drug deliveries depend on a daily heavy dosage of immune suppressants or anti-inflammatory drugs targeted for the treatment of two types of IBD, ulcerative colitis (UC) and Crohn's disease (CD), which are often associated with systemic side effects and adverse toxicities. Advances in oral delivery through nanotechnology seek remedies to overcome the drawbacks of these conventional drug delivery systems through improved drug encapsulation and targeted delivery. In this review, we discuss the association of genetic factors, the immune system, the gut microbiome, and environmental factors like diet in the pathogenesis of IBD. We also review the various physiological concerns required for oral delivery to the gastrointestinal tract (GIT) and new strategies in nanotechnology-derived, colon-targeting drug delivery systems.

Limited added value of laboratory monitoring in thiopurine maintenance monotherapy in inflammatory bowel disease patients

BACKGROUND

To timely detect myelotoxicity and hepatotoxicity, laboratory monitoring at 3-month intervals is advised throughout thiopurine maintenance treatment for IBD. However, reported incidence rates of myelotoxicity and hepatotoxicity in maintenance treatment are low.

AIM

To assess incidence rates and clinical consequences of myelotoxicity and hepatotoxicity in thiopurine maintenance therapy after at least 1 year of thiopurine treatment.

METHODS

Retrospective analysis of therapy adjustment for laboratory toxicity in adult IBD patients after 12 consecutive months of azathioprine (AZA) or mercaptopurine monotherapy (ie baseline) between 2000 and 2016. Incidence rates of laboratory toxicity (ie myelotoxicity [leucocyte count <4.0 × 10e9/L, and/or platelet count <150 × 10e9/L] and/or hepatotoxicity (gamma-glutamyltransferase [GGT], alkaline phosphatase [AP], ALT and/or AST above ULN, excluding isolated increased AST/AP]) and associated diagnostic procedures and complications were assessed.

RESULTS

In total, 12,391 laboratory assessments were performed on 1132 patients (56% female, AZA 74%) during 3.3 years of median follow-up. Median monitoring frequency was 3.1 assessments/treatment year. Only 83/12,391 (0.7%) assessments resulted in therapy adjustment, dose reduction in 46 patients, cessation in 28 and allopurinol initiation in nine; risk of therapy adjustment was 1.9% per treatment year. Incidence rates of myelotoxicity were 7.1% (5.1% mild/1.8% moderate/0.1% severe) and hepatotoxicity 5.1% (3.8% mild/1.1% moderate/0.2% severe) per treatment year. Treatment-related complications with concurrent laboratory toxicity occurred in 12 patients (1.1%) and would not have been prevented by monitoring.

CONCLUSION

Severe laboratory toxicity is uncommon after 1 year of thiopurine monotherapy at 4-month monitoring intervals. Therapy adjustments are rare after detection of laboratory toxicity. After 1 year of thiopurine monotherapy, laboratory monitoring may be lowered to less than a 4-month interval.

Importance of 6-Thioguanine Nucleotide Metabolite Monitoring in Inflammatory Bowel Disease Patients Treated with Azathioprine

The active metabolite of azathioprine, 6-thioguanine nucleotide (6-TGN) is the main component responsible for the immunosuppressive effect in treatment of inflammatory bowel disease (IBD). The aim of this study was to assess the correlation between the concentration of 6-thioguanine nucleotide and disease activity, azathioprine-related adverse effects and time duration of treatment in patients with inflammatory bowel disease. Thirty-four patients were included in this study. Type of disease, gender, time duration of therapy and adverse effects were recorded. Metabolite concentration was determined by high performance liquid chromatography. Twenty-one percent of patients have experienced an adverse effect, with leucocytopenia most commonly occurring (42.9%). More adverse effects were registered when patients were treated with azathioprine in a period of less than 3 months in comparison to the group of patients that have been under therapy between 3-12 months and more than 12 months (p˂0.05). Most of the patients that presented any adverse effect had high 6-TGN concentration (>450 pmol/8x108 Er). The mean value of 6-TGN metabolite concentration in IBD patients treated with azathioprine was 437.46 pmol/8x108 Er ± 198.82 pmol/8x108. The time duration of azathioprine treatment did not have any significant impact on the achieved 6-TGN concentration (p>0.05).Twenty patients (58.9%) had achieved remission after therapy initiation with azathioprine. More alertness is recommended to clinicians towards patients in the first 3 months of the therapy. Our study demonstrated that higher 6-TGN concentration is associated with azathioprine toxicity.

A Concise History of Thiopurines for Inflammatory Bowel Disease: From Anecdotal Reporting to Treat-to-Target Algorithms

BACKGROUND

The need for immune suppressive strategies in the control of chronic inflammatory bowel diseases originated in the 1960s following the perception of a relative inefficacy of salazopyrin and its derivatives. In some 50 years upon an anecdotal claim, the indication for thiopurines in the management of inflammatory bowel diseases has come of age.

OBJECTIVE

The aim of this minireview is to give an overview, after the historical premises, of the current use of thiopurines in the context of inflammatory bowel diseases.

METHOD

Through MEDLINE searches, we reviewed the literature of the last two decades.

RESULTS

For Crohn's disease, the 1980 trial of 6-mercaptopurine for steroid sparing and fistula closure proved pivotal. The analysis of withdrawal experiments and of numerous open trials has established the efficacy of thiopurines for ulcerative colitis. In this indication, cutting-edge data are now showing that because targeting dysplasia, thiopurines can induce mucosal/histological healing, thus abolishing or delaying the need for pre-emptive (tumor prophylactic) colectomy.

CONCLUSION

In UC thiopurines may be recognized to effect a treat-to-target strategy, joining the modern algorithms of rheumatologic disorders.

Safety of treatments for inflammatory bowel disease: Clinical practice guidelines of the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD)

Inflammatory bowel diseases are chronic conditions of unknown etiology, showing a growing incidence and prevalence in several countries, including Italy. Although the etiology of Crohn's disease and ulcerative colitis is unknown, due to the current knowledge regarding their pathogenesis, effective treatment strategies have been developed. Several guidelines are available regarding the efficacy and safety of available drug treatments for inflammatory bowel diseases. Nevertheless, national guidelines provide additional information adapted to local feasibility, costs and legal issues related to the use of the same drugs. These observations prompted the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) to establish Italian guidelines on the safety of currently available treatments for Crohn's disease and ulcerative colitis. These guidelines discuss the use of aminosalicylates, systemic and low bioavailability corticosteroids, antibiotics (metronidazole, ciprofloxacin, rifaximin), thiopurines, methotrexate, cyclosporine A, TNFα antagonists, vedolizumab, and combination therapies. These guidelines are based on current knowledge derived from evidence-based medicine coupled with clinical experience of a national working group.

Thiopurines and inflammatory bowel disease: Current evidence and a historical perspective

The use of thiopurines in inflammatory bowel disease (IBD) has been examined in numerous prospective, controlled trials, with a majority demonstrating a clinical benefit. We conducted this review to describe the historical and current evidence in the use of thiopurines in IBD. A systematic search was performed on MEDLINE between 1965 and 2016 to identify studies on thiopurines in IBD. The most robust evidence for thiopurines in IBD includes induction of remission in combination with anti-tumor necrosis factor (anti-TNF) agents, and maintenance of remission and post-operative maintenance in Crohn’s disease. Less evidence exists for thiopurine monotherapy in induction of remission, maintenance of ulcerative colitis, chemoprevention of colorectal cancer, and in preventing immunogenicity to anti-TNF. Evidence was often limited by trial design. Overall, thiopurines have demonstrated efficacy in a broad range of presentations of IBD. With more efficacious novel therapeutic agents, the positioning of thiopurines in the management of IBD will change and future studies will analyze the benefit of thiopurines alone and in conjunction with these new medications.

Routinely Established Skewed Thiopurine Metabolism Leads to a Strikingly High Rate of Early Therapeutic Failure in Patients With Inflammatory Bowel Disease

BACKGROUND

The conventional thiopurines azathioprine and mercaptopurine are considered maintenance immunosuppressive drugs of choice in the treatment of inflammatory bowel disease (IBD). Unfortunately, treatment is often discontinued because of adverse events (AEs) or refractoriness, retrospectively associated with the high levels of the thiopurine metabolites 6-methylmercaptopurine ribonucleotides (6-MMPR). Patients with a clinically "skewed" thiopurine metabolism may be particularly at risk for therapy failure. We determined the predictive value of this pharmacological phenomenon in patients with IBD during regular thiopurine therapy.

METHODS

Clinical effectiveness and tolerability of weight-based thiopurine therapy were determined in all patients with IBD displaying a skewed metabolism [ratio 6-MMPR/6-thioguanine nucleotide (6-TGN) >20]. All samples were routinely assessed between 2008 and 2012, as part of standard clinical follow-up after initiation of conventional thiopurine therapy.

RESULTS

Forty-one (84%) of 49 included patients with IBD discontinued thiopurines (55% female, 53% with Crohn disease) with a median duration of 14 weeks (range, 7-155). The majority of patients with a skewed metabolism discontinued thiopurines because of adverse events (55%) or refractoriness (12%). The most commonly observed adverse event was hepatotoxicity (18 patients, 37%). Median 6-TGN level was 159 pmol/8 × 10 RBC (range, 46-419), median 6-MMPR level was 11,020 pmol/8 × 10 RBC (range, 3610-43,670), and the median 6-MMPR/6-TGN ratio was 72 (range, 29-367). Thiopurine therapy failure was associated with a ratio above 50 (P < 0.03). Hepatotoxicity occurred more frequently in patients with an extremely skewed metabolism (6-MMPR/6-TGN ratio >100) (P < 0.01).

CONCLUSIONS

This study demonstrates that a routinely established skewed metabolism is a major risk factor for future thiopurine failure in patients with IBD. These observations imply that routine thiopurine metabolite measurements may be used as a prognostic tool to identify those patients with an aberrant-skewed metabolism at an early stage, possibly benefitting from therapy adjustments.

Predictors of Thiopurine Treatment Failure in Biologic-Naïve Ulcerative Colitis Patients

INTRODUCTION

Thiopurines (azathioprine and 6-mercaptopurine) have been used in the management of UC patients for over three decades. Nearly half of patients with UC treated with thiopurines fail to achieve remission or lose remission during treatment. Factors associated with thiopurine failure are poorly understood. The primary aim of our study was to investigate patient-related factors which are associated with thiopurine failure.

METHODS

TNF-alpha antagonist-naïve patients with histological diagnosis of UC, receiving thiopurine therapy, with follow-up data from 1 to 3 years were included in the study. Data regarding demographics, laboratory results, and disease characteristics were collected. The primary endpoint was failure of thiopurine therapy, defined as treatment with steroids, therapeutic escalation to TNF-alpha antagonist therapy, or need for surgery.

RESULTS

Of the 563 patients identified using ICD-9 codes, 78 TNF-alpha antagonist-naïve patients with a histological diagnosis of UC, receiving thiopurine treatment, were identified. Over the three-year follow-up period, 38 patients failed thiopurine treatment. On adjusted Cox regression, BMI < 25 kg/m(2) (HR 3, 95 % CI 1.55-5.83; p value = 0.001) was significantly associated with thiopurine failure. Furthermore, although not statistically significant, there was a strong trend toward thiopurine failure among patients with serum albumin level < 4 g/dL (HR 1.98, 95 % CI 0.97-4; p value = 0.06), non-smoking status (HR 2.2, 95 % CI 0.96-5.06; p value = 0.06), and higher degree of colon inflammation (HR 1.49, 95 % CI 0.96-2.32; p value = 0.08).

DISCUSSION

Our results show that low body mass index is associated with increased risk of failure of thiopurine treatment. Furthermore, there was a strong trend toward thiopurine failure among patients with low serum albumin level (<4gm/dL). These factors should be considered as markers of non-response to thiopurine monotherapy for patients with moderately severe ulcerative colitis.

Different Profile of Efficacy of Thiopurines in Ulcerative Colitis and Crohn's Disease

BACKGROUND

Thiopurines are effective drugs in treating ulcerative colitis (UC) and Crohn's disease (CD) even if studies that specifically investigate these drugs' profile of efficacy in UC compared with CD are scarce. Our aim was to compare the profile of efficacy of thiopurines in patients with UC and CD.

METHODS

We perfomed a longitudinal observational study evaluating steroid-free clinical remission (CR) and mucosal healing (MH) in all patients with UC and CD who would complete 2 years of maintenance treatment with thiopurines. In patients with UC, CR and MH were assessed before starting treatment and 2 years later using the Mayo score (CR = Mayo score <2; MH = Mayo subscore ≤1). In patients with CD, CR and MH were assessed at the same time points using the Crohn's disease activity index (CR = Crohn's disease activity index < 150) and the Simplified Endoscopic Score for Crohn's Disease (MH = Simplified Endoscopic Score for Crohn's Disease < 2). The efficacy of thiopurines was assessed through intention-to-treat and per-protocol analyses.

RESULTS

The study included 205 steroid-dependent patients (104 UC; 101 CD), 140 of whom (70 UC; 70 CD) completed the 2-year observation period. Steroid-free CR was recorded in 43 patients with UC and 37 with CD (intention-to-treat: 41% versus 36%; P = 0.6; per-protocol: 61% versus 53%; P = 0.4); MH was obtained in 38 patients with UC and 17 with CD (intention-to-treat: 36% versus 16%; P < 0.01; odds ratio, 2.9; per-protocol: 54% versus 25%; P < 0.01; odds ratio, 3.7).

CONCLUSIONS

Thiopurines are effective in maintaining steroid-free CR in both UC and CD although they show a better profile of efficacy in terms of MH in cases of UC.

Clinical predictors of thiopurine-related adverse events in Crohn's disease

AIM: To determine the incidence and predictors of thiopurine-related adverse events.

METHODS: Subjects with Crohn’s disease who were followed in the Alberta Inflammatory Bowel Disease Consortium patient database registry were identified. Retrospective chart review was conducted between August 5^th, 2010 and June 1^st, 2012. We collected data on: age at diagnosis; sex; disease location and behaviour at time of prescribing thiopurine; perianal fistulising disease at or prior to thiopurine prescription; smoking status at time of thiopurine prescription, use of corticosteroid within 6 mo of diagnosis; dosage, age at onset, and cessation of 5-aminosalicyclic acid (5-ASA); anti-tumour necrosis factor medication exposure and intestinal resection before thiopurine prescription. The primary outcome of interest was the first adverse event that led to discontinuation of the first thiopurine medication used. Logistic regression models were used to associate clinical characteristics with outcomes after adjusting for potential confounders. Risk estimates were presented as odds ratios (OR) with 95% CI. Effect modification by age and sex were explored.

RESULTS: Our cohort had a median follow-up duration of 5.8 years [interquartile range (IQR 25^th-75^th) 2.7-9.1]. Thiopurine therapy was discontinued in 31.3% of patients because of: hypersensitivity reactions (7.1%), acute pancreatitis (6.2%), gastrointestinal intolerance (5.4%), leucopenia (3.7%), hepatotoxicity (3.4%), infection (1.1%) and other reasons (4.3%). A higher incidence of thiopurine withdrawal was observed in patients over the age of 40 (39.4%, P = 0.007). A sex-by-age interaction (P = 0.04) was observed. Females older than 40 years of age had an increased risk of thiopurine discontinuation due to an adverse event (age above 40 vs age below 40, adjusted OR = 2.8; 95%CI: 1.4-5.6). In contrast, age did not influence thiopurine withdrawal in males (age above 40 vs below 40, adjusted OR = 0.9; 95%CI: 0.4-2.1). Other clinical variables (disease location and phenotype, perianal disease, smoking history, history of intestinal resection and prior 5-ASA or corticosteroid use) were not associated with an increased risk an adverse event leading to therapy cessation.

CONCLUSION: Thiopurine withdrawal due to adverse events is commoner in women over the age of 40 at prescription. These findings need to be replicated in other cohorts.

Enhanced colonic delivery of ciclosporin A self-emulsifying drug delivery system encapsulated in coated minispheres

OBJECTIVES

Investigate the potential of coated minispheres (SmPill®) to enhance localized Ciclosporin A (CsA) delivery to the colon.

METHODS

CsA self-emulsifying drug delivery systems (SEDDS) were encapsulated into SmPill® minispheres. Varying degrees of coating thickness (low, medium and high) were applied using ethylcellulose and pectin (E:P) polymers. In vitro CsA release was evaluated in simulated gastric and intestinal media. Bioavailability of CsA in vivo following oral administration to pigs of SmPill® minispheres was compared to Neoral® po and Sandimmun® iv in a pig model. CsA concentrations in blood and intestinal tissue were determined by HPLC-UV.

RESULTS

In vitro CsA release from coated minispheres decreased with increasing coating thickness. A linear relationship was observed between in vitro CsA release and in vivo bioavailability (r(2) = 0.98). CsA concentrations in the proximal, transverse and distal colon were significantly higher following administration of SmPill®, compared to Neoral® po and Sandimmun® iv (p < 0.05). Analysis of transverse colon tissue subsections also revealed significantly higher CsA concentrations in the mucosa and submucosa using SmPill® minispheres (p < 0.05).

CONCLUSIONS

Modulating E:P coating thickness controls release of CsA from SmPill® minispheres. Coated minispheres limited CsA release in the small intestine and enhanced delivery and uptake in the colon. These findings demonstrate clinical advantages of an oral coated minisphere-enabled CsA formulation in the treatment of inflammatory conditions of the large intestine.

CCR9 antagonism: potential in the treatment of Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD), mainly comprising Crohn’s disease (CD) and ulcerative colitis (UC), is a chronic condition that primarily affects the intestine and is characterized by leukocytic infiltration. Blocking the migration of leukocytes from the circulation is therefore a reasonable therapeutic goal. Recent clinical trials using this approach have shown promise, with the monoclonal antibody to α₄β₇ integrin, vedolizumab, and previously with the monoclonal antibody to the α₄ subunit, natalizumab. Directly targeting the subset of α₄β₇ expressing cells that co-express CC chemokine receptor 9 (CCR9), using the orally administered antagonist, CCX282-B, also known as vercirnon, has also been evaluated in Phase II and III trials that have produced mixed results. Although CCX282-B showed efficacy in inducing response in active CD in early studies, this was not confirmed in a Phase III study. CCX282-B was also more effective than placebo in maintaining remission, and this result has yet to be confirmed in Phase III. The efficacy of blocking CCR9 in UC, where vedolizumab was effective, has not been tested. The prospect of targeting CCR9 in IBD remains attractive. Much of the local accumulation of inflammatory cells in the intestine arises from migration rather than local proliferation and genetic and pharmacological targeting of CCR9 or its ligand in preclinical models that mimic UC and CD ameliorate inflammation in some cases. Furthermore, binding of chemokine ligands to receptor is a critical step in activating integrin binding, so there is a potential for synergistic action between integrin and chemokine antagonists. CCR9 is expressed on a smaller proportion of circulating cells than α₄β₇ integrin, which may offer greater specificity of effect, particularly in long term use. Furthermore, while α₄β₇ is widely expressed on T and B cell subsets, CCR9 is mainly expressed on effector memory Th1 cells. Indications for the use of intestine-specific integrin and chemokine receptor targeting may also extend beyond IBD, to include, for example, postoperative ileus, and primary sclerosing cholangitis.

How thiopurines are used for the treatment of inflammatory bowel diseases: an Italian survey

BACKGROUND

The ideal manner of thiopurine use in inflammatory bowel disease has not been defined. We aimed at investigating the attitudes of Italian gastroenterologists on thiopurine use.

METHODS

A web-based survey was performed among 295 gastroenterologists.

RESULTS

Overall, 70 surveys were completed. At baseline, thiopurine methyltransferase genotype and phenotype were not assessed by 87.1% and 97.1% of respondents, respectively. At treatment onset, 17.1% adopted full weight-calculated dose while 80.0% preferred escalating the dose. During treatment, 87.1% and 64.3% reduced the dose for myelo- and liver toxicity, respectively; 48.6% for increased pancreatic enzymes, 17.1% for fever, and 5.7% for arthralgia. A systematic shift from one thiopurine to the other was reported by 4.3% of respondents in case of failure, and by 5.7% for adverse effects. Forty-four gastroenterologists (62.9%) stopped thiopurine treatment after 5-7 years.

CONCLUSIONS

Several discrepancies regarding the use of thiopurines in clinical practice were found, deviating from available guidelines. A more standardised attitude is needed in clinical practice.

Early corticosteroids requirement after the diagnosis of ulcerative colitis diagnosis can predict a more severe long-term course of the disease - a nationwide study of 1035 patients

BACKGROUND

There are limited data regarding clinical outcomes in ulcerative colitis (UC) patients who require early corticosteroids (CS) use.

AIM

To evaluate the rate of early CS utilisation (within 30 days of diagnosis) as a predictive marker for long-term outcomes, colectomy and CS dependency, in a population-based cohort of incident UC cases.

METHODS

Nationwide data were obtained from the Veterans Affairs (VA) health care system for the period 2001-2011. Incident UC cases were identified. A retrospective cohort design and time-to-event survival analysis were used to track outcomes of interest. Cox regression multivariate analysis was employed.

RESULTS

One thousand and thirty-five newly diagnosed patients with UC were identified and included in the analysis; 236 (23%) of those patients required early CS therapy. Patients were followed-up over a median time of 4.7 years (IQR 2.8-6.8) after UC diagnosis. The 5-year cumulative probability of requiring colectomy varied significantly by early CS use status (13% among early CS users compared to 4% among those who did not require early CS treatment, P < 0.001). Similar variation in the 5-year cumulative probability of CS dependency by early CS status was observed. Early CS users were more likely to require colectomy 2.9 (CI 1.7-5.0, P < 0.001) and to become CS dependent 4.5 (95% CI 3.6-5.7, P < 0.001) than non-users.

CONCLUSIONS

Early CS use can help identify those patients who have a more active disease course of UC. Recognising this can be among the indicators that can help physicians identify patients who may require early initiation of more aggressive therapy.

Routine use of thiopurines in maintaining remission in pediatric Crohn’s disease

AIM: To evaluate the effectiveness of thiopurines in maintaining steroid-free remission in routine clinical practice.

METHODS: The multi-center Pediatric Inflammatory Bowel Disease Network (PIBDNet) cohort study prospectively collected data on thiopurine naïve patients initiating mercaptopurine (6MP) or azathioprine. Patients with a diagnosis of Crohn’s disease (CD) were included in our study upon entering remission as determined by physician global assessment (PGA) within 365 d of initiation of thiopurines. The primary outcome of the study was maintenance of steroid-free remission (SFR) at each follow up visit. Patients were considered treatment failures if there had been a change in PGA from remission to mild, moderate or severe disease; disease relapse between visits; need for rescue therapy (biologic therapy, methotrexate, steroids); thiopurine discontinuation, hospitalization or surgical intervention. A secondary outcome defined treatment failure as a change from remission to moderate or severe (not mild) in addition to the previously defined criteria.

RESULTS: Sixty-five of 182 patients in the PIBDNet registry met criteria for inclusion in this study. Forty-five of 65 (69%) of included patients achieved remission within 180 d of thiopurine initiation. For the primary outcome, 47% and 23% of patients remained in SFR at 6 and 12 mo. The mean thiopurine dose at initiation for the 65 included patients was 0.89 ± 0.31 mg/kg per day. Metabolite levels were obtained in 48% (31/65) of the included patients with a mean 6TG level of 258 pmole/8 × 10⁸ RBC ± 147. For the secondary outcome, 65% and 42% of patients remained in SFR at 6 and 12 mo.

CONCLUSION: Thiopurines were less effective in maintaining remission for pediatric CD in this “real world” cohort than has been previously described. Variation in thiopurine dosing and metabolite measurement was found among practitioners.

Crohn's disease outcome in patients under azathioprine: a tertiary referral center experience

BACKGROUND AND AIMS

Azathioprine is of major importance in the treatment of Crohn's disease; its efficacy has been showed in several works, but real-life data regarding its use is scarce. Our aim was to address the outcome of patients with Crohn's disease under azathioprine in the real-life setting.

METHODS

Crohn's disease patients followed at an Inflammatory Bowel Disease Outpatient Clinic under azathioprine were consecutively enrolled, being allocated in one of four groups. Two groups included patients on treatment with this drug, regarding its two major indications - prevention of post-operative recurrence and steroid-dependent disease; a third group included patients who needed infliximab in addition to azathioprine and a fourth group comprised patients who did not tolerate azathioprine.

RESULTS

A total of 221 patients were enrolled, 180 on azathioprine due to steroid-dependency (64 needing additional treatment with infliximab) and 41 for prevention of post-operative recurrence. Steroid-free remission was obtained in 48%. Immunosuppression decreased the number of hospitalized patients (64% vs 36%; p<0.001), but not the surgery rates per person per year. Azathioprine as a post-operative drug was effective in decreasing hospitalizations. The addition of infliximab decreased the number of patients hospitalized (p=0.009) and hospitalization rates per person per year (p<0.001), but had no effect in the surgery rates per person per year. Sixty patients (23%) experienced adverse effects with AZA, 39 requiring discontinuation of the drug.

CONCLUSIONS

In this real-life study, azathioprine had a long-term steroid sparing effect and reduced hospitalizations. Combination with infliximab reduced hospitalizations but did not decrease the surgery rate.

A trial of mercaptopurine is a safe strategy in patients with inflammatory bowel disease intolerant to azathioprine: an observational study, systematic review and meta-analysis

BACKGROUND

Thiopurines maintain remission and modify disease course in inflammatory bowel disease. Use is limited by intolerance and subsequent drug withdrawal in approximately 17% of patients treated with azathioprine. Previous case series have addressed the success rates of re-treatment with mercaptopurine in these individuals.

AIMS

To determine the rate of tolerance when trialling mercaptopurine in azathioprine-intolerant patients and the factors predictive of success, and to perform a systematic review and meta-analysis of these data with other published data sets.

METHODS

A retrospective observational study of 149 patients with IBD (82 with Crohn's disease and 67 with ulcerative colitis) previously intolerant of azathioprine subsequently treated with mercaptopurine was performed. A meta-analysis was undertaken of all published studies of mercaptopurine use in azathioprine-intolerant patients (455 patients in 11 included studies).

RESULTS

Mercaptopurine was tolerated by 58% of azathioprine-intolerant patients in the Edinburgh cohort. In the meta-analysis, 68% tolerated mercaptopurine. A higher proportion of those in the meta-analysis with GI toxicity (62%) or hepatotoxicity (81%) were able to tolerate mercaptopurine than those with flu-like illness (36%). Among those patients who ceased mercaptopurine for further adverse effects, 59% experienced the same adverse effect as they had with azathioprine.

CONCLUSIONS

This meta-analysis shows that switching to mercaptopurine is a safe therapeutic strategy for over two-thirds of azathioprine-intolerant patients and may help optimise immunomodulatory therapy in inflammatory bowel disease. A trial of mercaptopurine should be attempted in IBD patients (except those with acute pancreatitis or bone marrow aplasia) before considering thiopurine intolerance.

Safety of thiopurine therapy in inflammatory bowel disease: long-term follow-up study of 3931 patients

BACKGROUND

To evaluate the safety of thiopurines in patients with inflammatory bowel disease. To identify predictive factors associated with the development of thiopurine-induced adverse events.

METHODS

Long-term incidence of adverse events was estimated in patients from a prospectively maintained Spanish nationwide database using Kaplan-Meier analysis. Cox regression analysis was performed to identify potential predictive factors of adverse events.

RESULTS

Three thousand nine hundred and thirty-one patients were included. Ninety-five percent of patients were on azathioprine. The median follow-up with thiopurines was 44 months (range, 0-420). Adverse events occurred at a median of 1 month after starting treatment. The cumulative incidence of adverse events was 26%, with an annual risk of 7% per patient-year of treatment. Most frequent adverse events were nausea (8%), hepatotoxicity (4%), myelotoxicity (4%), and pancreatitis (4%). Four patients had lymphoma. Female and Crohn's disease increased the risk of having nausea. The risk of hepatotoxicity was lower in females and higher in Crohn's disease. The risk of myelotoxicity was significantly higher in patients treated with mercaptopurine and in females. The risk of pancreatitis was higher in Crohn's disease. Overall, 17% of patients discontinued thiopurine treatment due to adverse events. Thirty-seven percent of these patients started thiopurines again and 40% of them had adverse events again.

CONCLUSIONS

As many as 1 of 4 patients on thiopurine therapy had adverse events during follow-up. A relatively high proportion of patients (17%) had to discontinue the treatment with thiopurines due to adverse events. However, more than half of patients that restarted thiopurine treatment after its discontinuation due to adverse events tolerated it. Several predictive factors for some adverse events have been identified.

The impact of inflammatory bowel disease post-liver transplantation for primary sclerosing cholangitis

BACKGROUND

An association between primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) is well recognized. However, the disease course of IBD following liver transplantation (LT) for PSC remains ill-defined.

AIMS AND METHODS

We aimed to assess the impact of IBD in patients that had undergone LT for PSC to help identify risk factors for flare and to assess the impact of IBD on graft survival.

RESULTS

110 patients underwent LT for PSC (Oct 1990-Aug 2009) at King's College Hospital. 74 (67%) patients had concurrent IBD and 36 had PSC alone prior to transplant. 39 patients developed IBD (flare of IBD and de-novo) post transplant. Cumulative risk for IBD at 1-, 2-, 5- and 10-years was 16%, 24%, 38% and 72% respectively. Flare of IBD occurred in 33 patients with a mean time to flare of 30 ± 28 months. De-novo IBD occurred in 6 patients (all UC). Mean time to diagnosis was 29 ± 25 months. Multivariate cox-regression analysis identified active IBD at time of LT as a significant predictor of graft failure post LT (HR 10, CI 3-39, P = 0.001) and smoking at time of transplantation and subsequent cessation predictive of recurrent IBD post transplantation (HR 17, 2-180, P = 0.02).

CONCLUSION

In conclusion, smoking at time of LT was predictive of flare of IBD and active IBD at time of transplantation had a significant effect on graft survival. Medical therapy needs to be maximised in the pre-LT period. Patients with poorly controlled IBD refractory to medical therapy should be considered for colectomy at time of transplantation.

A novel stimuli-synchronized alloy-treated matrix for space-defined gastrointestinal delivery of mesalamine in the Large White pig model

The study focussed on designing a Stimuli-Synchronized Matrix (SSM) for space-defined colonic delivery of the anti-inflammatory drug mesalamine. The configured matrix provided time-independent delivery and stimuli targeting. Formulations were optimized according to a Box-Behnken experimental design that constituted mesalamine-loaded BaSO4-crosslinked chitosan dispersed within a pectin, carboxymethylcellulose and xanthan gum complex. The complex was compressed into matrices and subsequently alloy-treated with pectin and ethylcellulose. In vitro drug release was determined in the presence and absence of colonic enzymes and the mean dissolution time was used for formulation optimization. To mechanistically elucidate the synchronous catalytic action of the enzymes pectinase and glucosidase on the matrix, computer-aided 3D modelling of active fractions of the enzyme-substrate complexes was generated to predict the orientation of residues affecting the substrate domain. Drug release profiles revealed distinct colonic enzyme responsiveness with fractions of 0.402 and 0.152 of mesalamine released in the presence and absence of enzymes, respectively after 24h. The commercial comparator product showed irreproducible release profiles over the same period (SD=0.550) compared to the SSM formulation (SD=0.037). FTIR spectra of alloy-treated matrices showed no peaks from 1589 to 1512cm(-1) after colonic enzyme exposure. With increasing enzyme exposure there were also no peaks between 1646 and 1132cm(-1). This indicated polymeric enzyme cleavage for controlled and space-defined release of mesalamine. Plasma concentration profiles in the Large White pig model produced a Cmax of 3.77±1.375μg/mL compared to 10.604±2.846μg/mL for the comparator formulation. The SSM formulation proved superior over the comparator product by providing superiorly controlled enzyme-responsive colonic drug delivery.

Thiopurine treatment in inflammatory bowel disease: response predictors, safety, and withdrawal in follow-up

BACKGROUND AND AIMS

Thiopurines represent the mainstay of immunosuppressive therapy in inflammatory bowel diseases. Since it is likely that response to therapy and adverse events depends on the genetic background of patients our study aimed to evaluate retrospectively response to therapy and safety in a mixed IBD population in Southern Europe.

METHODS

We evaluated demographic and clinical data of our patients treated with thiopurines. after 6 months in responders and non-responders to therapy. Moreover the likelihood to remain in thiopurine monotherapy was evaluated in responders, whereas adverse events were investigated in all patients.

RESULTS

Among disease- and patient-related parameters a shorter disease duration, female gender and ileal disease in Crohn's patients were associated with better response. By ROC analysis, the best predictors of response were decreasing values of C-reactive protein and erythrocyte sedimentation rate. In the long-term more than half of IBD patients who responded at 6 months remained on monotherapy at 42 months. Flu-like syndrome represented the most frequent adverse event followed by abnormalities of liver function tests and myelotoxicity. Adverse events did occur at any time and were frequently impredictable.

CONCLUSIONS

In this retrospective study, thiopurines showed a good clinical efficacy, especially in patients with short duration of disease. Normalization of markers of systemic inflammation represents the most useful tool to assess response. Careful monitoring of patients is required during the whole duration of treatment although it may not prevent all severe complications.

Current status of thiopurine analogues in the treatment in Crohn's disease

In the last decades, with the development of biological therapy, the treatment paradigms in patients with Crohn’s disease have continuously evolved. Several studies focusing on the optimal use of both traditional immunosuppressants and biological therapy have been published, investigating conventional, accelerated step-up and top-down approaches. In addition, much emphasis has been placed in recent years on the determination of important predictive factors that could enable early patient stratification, which would lead to a tailored management strategy. In this review, the authors try to highlight new evidence on the optimal timing, benefits, and risks of immunosuppressants alone, or in combination, in patients with Crohn’s disease.

Adverse events of thiopurine immunomodulators in patients with inflammatory bowel disease

BACKGROUND

Thiopurine immunomodulators are the most commonly used immunosuppressants in inflammatory bowel disease.

AIMS

To evaluate the incidence of adverse events (AE) in patients with inflammatory bowel disease treated with azathioprine (AZA) or 6-mercaptopurine (MP) in our hospital, the features of these effects, the distribution of socio-demographic factors, and the possible predisposing factors.

METHODS

We included 377 patients with inflammatory bowel disease who were diagnosed through 2008 and who received AZA or MP during the course of their disease. We collected retrospective demographic, clinical, and laboratory data about their disease and detailed information on any AE.

RESULTS

Fifty-one patients had some form of AE with AZA or MP (13.5%) and 11% discontinued therapy because of toxicity. Statistically significant association with Crohn's disease was found (P = .008). Myelotoxicity occurred in 18 patients (4.8%) with a mean time of laboratory abnormalities appearing after 16 months. Nine patients had hepatotoxicity secondary to these drugs (2.4%); one of them developed nodular regenerative hyperplasia and portal hypertension. Ten patients had acute pancreatitis (2.7%) with a mean time occurrence of 27 days and a statistically significant association with Crohn's disease (P = .03) and smoking (P = .01). Fifteen patients had gastrointestinal intolerance (4%) but 5 were able to continue with medication given in divided doses or switching to MP.

CONCLUSIONS

Thiopurine immunomodulators have a significant percentage of AE (13.5%), which, although usually mild, forced us to follow up all cases and sometimes even suspend treatment.

Smoking status and response to thiopurines in steroid-dependent inflammatory bowel disease

BACKGROUND

The influence of smoking on inflammatory bowel disease (IBD) susceptibility and on its clinical course is well known, but not its impact on drug efficacy. The aim of this study was to evaluate the response to thiopurines in patients with steroid-dependent IBD according to their smoking habits.

METHODS

The medical records of 163 IBD patients (103 Crohn's disease [CD], 60 ulcerative colitis [UC]) in whom thiopurines were started because of steroid-dependency were reviewed. Therapeutic response was defined by steroid-free clinical remission for at least 6 months after 12 months of starting thiopurines. Clinical data and smoking status at diagnosis, at the time thiopurines were started, and during the follow-up were registered.

RESULTS

A therapeutic response was obtained in 72% of CD and 61% of UC patients. Smoking habits did not influence the rate of response to thiopurines, the need for rescue therapies, or the development of penetrating/stricturing complications (CD) or proximal progression (UC). However, CD responders who continued smoking required new courses of steroids more often during follow-up. No influence of smoking was found when these outcomes were analyzed depending on gender or disease location. In the multivariate analysis, smoking status was the only predictive factor of drug tolerance.

CONCLUSIONS

Active smoking does not influence the response to thiopurines in steroid-dependent IBD, but may decrease the likelihood of drug tolerance.

Thiopurines in Crohn's disease, is there something new?

IMPORTANCE OF THE FIELD

traditional immunosuppressants, including azathioprine, remain the mainstay of therapy in steroid dependent/refractory patients with inflammatory bowel diseases (IBD). The main limitations of its use are its side effects appearing in about a fifth of the patients, including myelosuppression and liver toxicity. Major complications occur in patients with low thiopurine-S-methyltransferase (TPMT) enzyme activity; however, the clinical relevance of these tests remains conflictive.

AREAS COVERED IN THIS REVIEW

in this review, the authors aim to summarize the new data regarding the relationship between the pharmacology of thiopurines and pathogenesis of adverse events.

WHAT THE READER WILL GAIN

readers will gain an understanding of the metabolism of thiopurines, side effect profile, pharmacological background of side effects, importance of metabolite monitoring, clinical relevance of inherited differences in drug metabolism and other conditions (e.g., concomitant use of allopurinol) which can modify enzyme activity. By gaining an understanding of the pharmacology and metabolism of thiopurines, clinicians will be able to optimize thiopurine therapy in IBD.

TAKE HOME MESSAGE

TPMT testing and metabolite monitoring are still not considered the standard of care, and clinicians will continue to choose the approach that best suits their clinical practice and patient needs. Regardless of what strategy is chosen, patients need to be carefully monitored and well informed about the potential risks.

Thiopurine therapy in inflammatory bowel disease patients: analyses of two 8-year intercept cohorts

BACKGROUND

Thiopurines have proven efficacy in long-term maintenance therapy of inflammatory bowel disease (IBD). Limited data are available with regard to factors predicting effectiveness and failure of long-term thiopurine use in IBD patients.

METHODS

The data in this retrospective study are based on an 8-year intercept cohort of previous or present thiopurine-using IBD patients. Both cohorts are assessed by descriptive and statistical analysis aimed at determining thiopurine effectiveness and the variables that are predictive for failure of thiopurine therapy.

RESULTS

In all, 363 IBD patients were included (60% female), 63% with Crohn's disease and 33% with ulcerative colitis. Overall, thiopurines were continued in 145/363 (40%) and discontinued in 208/363 (57%) patients. The proportion of patients still using thiopurines at 3, 6, 12, 24, and 60 months was 73%, 69%, 63%, 51%, and 42%, respectively. Patients discontinued thiopurines due to adverse events (39%), refractoriness (16%), and ongoing remission / patient's request (4%). 6-methylmercaptopurine (6-MMP) concentration and 6-MMP/6-thioguanine nucleotides (6-TGN) ratio were significant higher in the failure group. Prolonged continuation of thiopurines was associated with a decreased risk of discontinuation.

CONCLUSIONS

Azathioprine and 6-mercaptopurine were considered effective in approximately 40% of IBD patients after 5 years of treatment. A quarter of the patients discontinued thiopurines within 3 months, mostly due to adverse events. A high 6-MMP concentration or 6-MMP/6-TGN ratio was associated with therapeutic failure. If thiopurine use was successfully initiated in the first months, its use was usually extended over many years, as long-term use was associated with continuation of therapy.

Emerging drugs for the treatment of ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing inflammatory disorder of the colon for which the etiology is currently unknown. At present, strategies to treat UC are primarily targeted to control inflammation during active phases of disease as well as maintain remission during quiescence. As such, several unmet needs in the treatment of UC still remain. In recent years, basic research has led to the recognition of several key factors in the pathogenesis of UC, translating into the development of several novel therapeutic agents.

OBJECTIVE

The aim of this study is to review emerging therapies that may advance the treatment and improve the overall care of UC patients.

METHODS

An extensive literature search on published manuscripts and meeting proceedings has been performed to provide a comprehensive review of future drug therapies to treat UC.

RESULTS/CONCLUSION

The translational application of new discoveries in the basic understanding of UC pathogenesis is continuing and critical for the development of novel treatment strategies. Design of novel biologic therapies to treat UC has the challenge of addressing potential safety issues, while more traditional drugs should be further developed to facilitate patient compliance to treat this chronic, debilitating disease.