Thiopurine Treatment in Ulcerative Colitis: A Critical Review of the Evidence for Current Clinical Practice

Thiopurines exert harmful effects on spermatogenesis in Nudt15R138C knock-in mice

BACKGROUND

The association between thiopurine use and testicular reproductive functions remains unclear. In this study, we investigated whether thiopurines affect testicular functions based on the NUDT15 genotypes using Nudt15R138C knock-in mice.

METHODS

The male Nudt15R138C knock-in mice (9-12 weeks) were treated with mercaptopurine (MP: 0.5 mg/kg/day) for 4 or 12 weeks. To examine reversibility, some mice were maintained for a further 12 weeks under MP-free condition.

RESULTS

After MP treatment for 4 weeks, Nudt15R138C/R138C mice exhibited a significant reduction of testis weight compared to Nudt15+/+ mice and Nudt15+/R138C mice. The epithelial height and diameter of seminiferous tubules were significantly reduced in Nudt15R138C/R138C mice compared to Nudt15+/+ and Nudt15+/R138C mice. Apoptotic cells were significantly increased in Nudt15R138C/R138C mice, and most of apoptotic cells were spermatogonia. There were no significant changes in sperm counts and sperm morphology in MP-treated Nudt15R138C/R138C mice after 4-week MP treatment. On the other hand, after MP treatment for 12 weeks, the Nudt15+/R138C mice, but not Nudt15+/+ mice, exhibited a significant reduction in the testis weight and atrophic changes of seminiferous tubules, but these changes disappeared after 12-week rearing under MP-free condition. Despite a significant increase in abnormal sperm rate, there were no changes in the ability to conceive. No differences in serum levels of follicle-stimulating hormone or testosterone were observed between MP-treated Nudt15+/R138C and Nudt15+/+ mice after 12-week MP treatment.

CONCLUSIONS

Thiopurines exert harmful effects on testicular reproductive function according to host NUDT15 genotypes.

Clinician's Guide to Using Ozanimod for the Treatment of Ulcerative Colitis

The emergence of advanced therapies [eg, biologics, Janus kinase inhibitors] over the past few decades has revolutionised the treatment of ulcerative colitis. However, the limitations of these therapies leave an unmet need for safer and more effective or convenient treatment options. There is growing interest in the development of novel oral small molecule therapies for the treatment of ulcerative colitis. Ozanimod is an oral small molecule therapy that is approved in the USA, the European Union, and other countries as the first sphingosine 1-phosphate receptor modulator for the treatment of moderately to severely active ulcerative colitis in adults. This review provides guidance for ozanimod use for the treatment of ulcerative colitis, based on the prescribing information, clinical trial and real-world data, and the authors' clinical experiences. This guidance outlines patient characteristics to consider when deciding if ozanimod treatment is suitable and describes how to educate patients on risks and best practices. It also details the nature and frequency of monitoring during treatment, which should be adapted to the individual patient based on pre-existing risk factors and events that possibly occur during treatment. This review also provides insights into the patient characteristics and clinical scenarios best suited for ozanimod treatment, based on its efficacy, safety profile, and risks compared with other therapies.

Efficacy of cytapheresis in patients with ulcerative colitis showing insufficient or lost response to biologic therapy

For the optimal management of refractory ulcerative colitis (UC), secondary loss of response (LOR) and primary non-response to biologics is a critical issue. This article aimed to summarize the current literature on the use of cytapheresis (CAP) in patients with UC showing a poor response or LOR to biologics and discuss its advantages and limitations. Further, we summarized the efficacy of CAP in patients with UC showing insufficient response to thiopurines or immunomodulators (IM). Eight studies evaluated the efficacy of CAP in patients with UC with inadequate responses to thiopurines or IM. There were no significant differences in the rate of remission and steroid-free remission between patients exposed or not exposed to thiopurines or IM. Three studies evaluated the efficacy of CAP in patients with UC showing an insufficient response to biologic therapies. Mean remission rates of biologics exposed or unexposed patients were 29.4 % and 44.2%, respectively. Fourteen studies evaluated the efficacy of CAP in combination with biologics in patients with inflammatory bowel disease showing a poor response or LOR to biologics. The rates of remission/response and steroid-free remission in patients with UC ranged 32%-69% (mean: 48.0%, median: 42.9%) and 9%-75% (mean: 40.7%, median: 38%), respectively. CAP had the same effectiveness for remission induction with or without prior failure on thiopurines or IM but showed little benefit in patients with UC refractory to biologics. Although heterogeneity existed in the efficacy of the combination therapy with CAP and biologics, these combination therapies induced clinical remission/response and steroid-free remission in more than 40% of patients with UC refractory to biologics on average. Given the excellent safety profile of CAP, this combination therapy can be an alternative therapeutic strategy for UC refractory to biologics. Extensive prospective studies are needed to understand the efficacy of combination therapy with CAP and biologics.

Efficacy and Safety of Probiotics Combined With Traditional Chinese Medicine for Ulcerative Colitis: A Systematic Review and Meta-Analysis

Background: The combination of probiotics and traditional Chinese medicine (TCM) is a prospective therapy for ulcerative colitis (UC), and its efficacy and safety need to be urgently evaluated.

Objective: This study aims to comprehensively assess the efficacy and safety of probiotics combined with TCM for the treatment of UC.

Methods: The Pubmed, EMBASE, Cochrane library, China Academic Journals (CNKI), Wan-fang database, Chinese biomedical literature service system (CBM), and Chinese Science and Technology Journals (CQVIP) were searched. Subgroup analysis were designed in accordance with different control drugs, treatment courses, and types of probiotics. The Review Manager software (version 5.4.1) was utilized for statistical analysis.

Results: 14 original studies containing 1,154 patients were analyzed and showed that probiotics with TCM was more effective than 5-aminosalicylic acid (5-ASA), probiotics or TCM used individually. Moreover, probiotics combined with TCM could inhibit the intestinal inflammation, reduce the recurrence rate and the incidence of adverse events. The subgroup analysis showed that a mixture of different probiotics was more effective than a single strain.

Conclusion: It is suggested that probiotics combined with TCM could effectively control clinical symptoms, inhibit intestinal inflammatory response, and finally slow down the disease progress and reduce the disease recurrence with less adverse events. The mixture of different probiotics used in conjunction with individually tailored TCM is a potential clinical strategy for UC.

The Communication Between Intestinal Microbiota and Ulcerative Colitis: An Exploration of Pathogenesis, Animal Models, and Potential Therapeutic Strategies

Ulcerative Colitis (UC) is a chronic inflammatory bowel disease. The prolonged course of UC and the lack of effective treatment management make it difficult to cure, affecting the health and life safety of patients. Although UC has received more attention, the etiology and pathogenesis of UC are still unclear. Therefore, it is urgent to establish an updated and comprehensive understanding of UC and explore effective treatment strategies. Notably, sufficient evidence shows that the intestinal microbiota plays an important role in the pathogenesis of UC, and the treating method aimed at improving the balance of the intestinal microbiota exhibits a therapeutic potential for UC. This article reviews the relationship between the genetic, immunological and microbial risk factors with UC. At the same time, the UC animal models related to intestinal microbiota dysbiosis induced by chemical drugs were evaluated. Finally, the potential value of the therapeutic strategies for restoring intestinal microbial homeostasis and treating UC were also investigated. Comprehensively, this study may help to carry out preclinical research, treatment theory and methods, and health management strategy of UC, and provide some theoretical basis for TCM in the treatment of UC.

Early thiopurine maintenance is associated with reduced proximal disease progression and colectomy rate in ulcerative colitis

BACKGROUND

Thiopurines effectively maintain remission in ulcerative colitis patients. Whether early initiation of thiopurines after ulcerative colitis diagnosis decreases proximal disease progression and colectomy rates is not known.

METHODS

We conducted a cohort study of ulcerative colitis subjects recruited from 1970 to 2009. Early thiopurine maintenance was defined as commencement of azathioprine or mercaptopurine within 5 years of diagnosis and maintenance for at least 6 months. Propensity score matching was conducted to correct for confounders influencing early thiopurine introduction. Outcomes of interest were colectomy rate and endoscopic proximal disease extension.

RESULTS

982 consecutive ulcerative colitis subjects (12 879 patient-years) were recruited with 116 requiring colectomy. Thiopurines initiation and maintenance increased over time with median time to thiopurine commencement decreasing from 23 years in the first decade to 2 years in the last decade (P < 0.0001). Multivariate analysis showed that early thiopurine maintenance significantly decreased the need for colectomy [hazard ratio, 0.13; 95% confidence interval (CI):0.03-0.55; P = 0.006]. The number of subjects needed to be treated to reduce one colectomy at 5 and 10 years was 18 (95% CI, 16- 36) and 12 (95% CI, 11-25). After propensity score matching, early thiopurine maintenance was significantly associated with decreased colectomy (hazard ratio, 0.10; 95% CI, 0.03-0.43; P = 0.002) and proximal progression of disease extent (hazard ratio, 0.26; 95% CI, 0.10-0.78; P = 0.015).

CONCLUSION

Early thiopurine maintenance for >6 months is significantly associated with reduced colectomy and proximal progression of disease extent in ulcerative colitis.

Thiopurine pharmacogenomics and pregnancy in inflammatory bowel disease

The thiopurine drugs azathioprine and 6-mercaptopurine are widely used for the maintenance of clinical remission in steroid-dependent inflammatory bowel disease (IBD). Thiopurines are recommended to be continued throughout pregnancy in IBD patients, but conclusive safety data in pregnant patients remain still insufficient. On the other hand, a strong association between a genetic variant of nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15 p.Arg139Cys) and thiopurine-induced myelotoxicity has been identified. Pharmacokinetic studies have revealed that thiopurine metabolism is altered in pregnant IBD patients and suggested that the fetus may be exposed to the active-thiopurine metabolite, 6-thioguaninetriphosphate, in the uterus. A recent study using knock-in mice harboring the p.Arg138Cys mutation which corresponds to human p.Arg139Cys showed that oral administration of 6-MP at clinical dose induces a severe toxic effect on the fetus harboring the homozygous or heterozygous risk allele. This suggests that NUDT15 genotyping may be required in both women with IBD who are planning pregnancy (or pregnant) and their partner to avoid adverse outcomes for their infant. The risk to the fetus due to maternal thiopurine use is minimal but there are some concerns that are yet to be clarified. In particular, a pharmacogenomic approach to the fetus is considered necessary.

Differential effects of mesalazine formulations on thiopurine metabolism through thiopurine S-methyltransferase inhibition

BACKGROUND AND AIM

Thiopurines are often used in combination with mesalazine for the treatment of ulcerative colitis (UC). Mesalazine formulations are delivered to the digestive tract by various delivery systems and absorbed as 5-aminosalicylic acid (5-ASA). 5-ASA is known to inhibit thiopurine S-methyltransferase (TPMT) activity and to affect thiopurine metabolism. There have been no studies comparing TPMT inhibition by multimatrix mesalazine (MMX) with other formulations. We investigated the difference in TPMT inhibition by different mesalazine formulations and prospectively confirmed the clinical relevance.

METHODS

Plasma concentrations of 5-ASA, N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA), and TPMT activities were measured in UC patients receiving various mesalazine formulations (time-dependent or pH-dependent mesalazine or MMX) as monotherapy. Patients already on both time-dependent or pH-dependent mesalazine and thiopurines switched their mesalazine to MMX, examining 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine (6-MMP) 0 and 8 weeks after switching. Clinical relapse after switching was also monitored for 24 weeks.

RESULTS

Plasma 5-ASA and N-Ac-5-ASA levels were significantly higher in patients receiving time-dependent mesalazine (n = 12) compared with pH-dependent mesalazine (n = 12) and MMX (n = 15), accompanied by greater TPMT inhibition. Prospective switching from time-dependent mesalazine to MMX decreased 6-TGN levels, increased those of 6-MMP, and increased 6-MMP/6-TGN ratios. Furthermore, this resulted in significantly more relapses than switching from pH-dependent mesalazine to MMX.

CONCLUSIONS

Time-dependent mesalazine has higher plasma 5-ASA and N-Ac-5-ASA levels and greater TPMT inhibition than MMX. Therefore, switching from time-dependent mesalazine to MMX may lead to an increase of 6-MMP/6-TGN, which may reduce the clinical effectiveness of thiopurines, warranting close monitoring after switch.

Poor Drug Sustainability in Inflammatory Bowel Disease Patients in Clinical Remission on Thiopurine Monotherapy

BACKGROUND

Immunomodulator monotherapy is an important component in the treatment of inflammatory bowel disease (IBD). However, there is conflicting literature about thiopurines maintaining long-term remission in patients with active IBD.

AIM

To determine the durable clinical remission rate in adults with Crohn's disease (CD) or ulcerative colitis (UC) on thiopurine monotherapy over 5 years.

METHODS

We performed a retrospective analysis of adult patients identified at McGill University Health Centre from 2009 to 2012. We included IBD patients who initiated thiopurine monotherapy and were in remission for at least 3 months (Harvey-Bradshaw Index (HBI) < 5 points for CD and partial Mayo Score (pMS) < 2 points in UC). The primary endpoint was sustained clinical remission on thiopurines during a 5-year follow-up. This included patients who had not relapsed or discontinued the drug due to side effects. The secondary endpoint was clinical relapse over the follow-up period, which was defined as HBI > 5 in CD and pMS > 2 in UC.

RESULTS

There were 148 patients included in the study (100 CD; 48 UC). At 5 years, 23% (34/148) patients remained in clinical remission on thiopurine monotherapy (25 CD and 9 UC patients). Thirty-three percent (33/100) of CD and 46% (22/48) of UC patients relapsed while on thiopurines. There was no difference in relapse rates between CD and UC patients. Eighty-four percent (42/50) of patients with CD with side effects and all UC (17/17) patients who experienced side effects discontinued the drug.

CONCLUSION

This analysis demonstrates that there is poor sustainability of clinical remission in IBD patients on thiopurine monotherapy given that a high proportion of patients discontinue thiopurines due to either relapse or side effects.

Cytapheresis re-induces high-rate steroid-free remission in patients with steroid-dependent and steroid-refractory ulcerative colitis

BACKGROUND

It is a crucial issue for patients with refractory ulcerative colitis (UC), including steroid-dependent and steroid-refractory patients, to achieve and maintain steroid-free remission. However, clinical studies focused on the achievement of steroid-free remission in refractory UC patients are insufficient. Cytapheresis (CAP) is a non-pharmacological extracorporeal therapy that is effective for active UC with fewer adverse effects. This study comprised UC patients treated with CAP and suggested the efficacy of CAP for refractory UC patients.

AIM

To clarify the efficacy of CAP in achieving steroid-free remission in refractory UC patients.

METHODS

We retrospectively reviewed the collected data from 55 patients with refractory UC treated with CAP. We analyzed the following points: (1) Efficacy of the first course of CAP; (2) Efficacy of the second, third, and fourth courses of CAP in patients who experienced relapses during the observation period; (3) Efficacy of CAP in colonic mucosa; and (4) Long-term efficacy of CAP. Clinical efficacy was evaluated using Lichtiger's clinical activity index or Sutherland index (disease activity index). Mucosal healing was evaluated using Mayo endoscopic subscore. The primary and secondary endpoints were the rate of achievement of steroid-free remission and the rate of sustained steroid-free remission, respectively. Statistical analysis was performed using the paired t-test and chi-squared test.

RESULTS

The rates of clinical remission, steroid-free remission, and poor effectiveness after CAP were 69.1%, 45.5%, and 30.9%, respectively. There were no significant differences in rate of steroid-free remission between patients with steroid-dependent and steroid-refractory UC. The mean disease activity index and Lichtiger's clinical activity index scores were significantly decreased after CAP (P < 0.0001). The rates of steroid-free remission after the second, third, and fourth courses of CAP in patients who achieved steroid-free remission after the first course of CAP were 83.3%, 83.3%, and 60%, respectively. Mucosal healing was observed in all patients who achieved steroid-free remission after the first course of CAP. The rates of sustained steroid-free remission were 68.0%, 60.0%, and 56.0% at 12, 24, and 36 mo after the CAP. Nine patients (36%) had maintained steroid-free remission throughout the observation period.

CONCLUSION

Our results suggest that CAP effectively induces and maintains steroid-free remission in refractory UC and re-induces steroid-free remission in patients achieving steroid-free remission after the first course of CAP.

Natural Disease Course of Ulcerative Colitis During the First Five Years of Follow-up in a European Population-based Inception Cohort-An Epi-IBD Study

BACKGROUND AND AIMS

Few population-based cohort studies have assessed the disease course of ulcerative colitis [UC] in the era of biological therapy and widespread use of immunomodulators. The aim of this study was to assess the 5-year outcome and disease course of patients with UC in the Epi-IBD cohort.

METHODS

In a prospective, population-based inception cohort of unselected patients with UC, patients were followed up from the time of their diagnosis, which included the collection of their clinical data, demographics, disease activity, medical therapy, and rates of surgery, cancers, and deaths. Associations between outcomes and multiple covariates were analysed by Cox regression analysis.

RESULTS

A total of 717 patients were included in the study. During follow-up, 43 [6%] patients underwent a colectomy and 163 [23%] patients were hospitalised. Of patients with limited colitis [distal to the left flexure], 90 [21%] progressed to extensive colitis. In addition, 92 [27%] patients with extensive colitis experienced a regression in disease extent, which was associated with a reduced risk of hospitalisation (hazard ratio [HR]: 0.5 95% CI: 0.3-0.8]. Overall, patients were treated similarly in both geographical regions; 80 [11%] patients needed biological therapy and 210 [29%] patients received immunomodulators. Treatment with immunomodulators was found to reduce the risk of hospitalisation [HR: 0.5 95% CI: 0.3-0.8].

CONCLUSIONS

Although patients in this population-based cohort were treated more aggressively with immunomodulators and biological therapy than in cohorts from the previous two decades, their disease outcomes, including colectomy rates, were no different. However, treatment with immunomodulators was found to reduce the risk of hospitalisation.