The long-term efficacy of azathioprine does not wane after four years of continuous treatment in patients with steroid-dependent luminal Crohn's disease

Pancreatitis associated with azathioprine and 6-mercaptopurine use in Crohn's disease: a systematic review

Thiopurines are proven agents in the treatment of Crohn's disease. While pancreatitis is recognised as an adverse event associated with therapy, the effect size and morbidity of thiopurine-induced pancreatitis is not known. The aim of this systematic review and meta-analysis was to quantify the risk of pancreatitis with azathioprine and 6-mercaptopurine (6-MP) within Crohn's disease. We searched six electronic databases from inception to 29 October 2019. The primary outcomes measures were the occurrence of pancreatitis. We calculated pooled OR with corresponding 95% CIs for risk of pancreatitis. A number needed to harm analysis was performed. The search identified 4418 studies, of which 25 randomised controlled trials met the criteria for inclusion. The number of patients treated with azathioprine to cause an episode of pancreatitis was 36 (induction of remission) and 31 (maintenance of remission). The risk of pancreatitis in patients receiving azathioprine across all contexts was 3.80%, compared with a control risk of 0.2% (placebo) and 0.5% (5-aminosalicylic acid agents). There was no difference seen between 6-MP and placebo, although this was a low certainty result due to imprecision from very low event numbers and patient numbers. There is a probably increased occurrence of pancreatitis when azathioprine is used in Crohn's disease (moderate certainty), with incidence overall approximately 3.8%. Most cases are mild and resolve on cessation of therapy and no mortality was reported. There was no increased occurrence seen when using 6-MP, although this is a low certainty finding. PROSPERO prior to the study (CRD42019138065).

Azathioprine or 6-mercaptopurine for maintenance of remission in Crohn's disease

BACKGROUND

The therapeutic role of 6-mercaptopurine (6-MP) and azathioprine (AZA) remains controversial due to their perceived relatively slow-acting effect and adverse effects. An updated meta-analysis was performed to evaluate the efficacy of these agents for the maintenance of remission in quiescent Crohn's disease.

OBJECTIVES

To assess the efficacy of AZA and 6-MP for maintenance of remission in quiescent Crohn's disease.

SEARCH METHODS

We searched MEDLINE, EMBASE, and the Cochrane Library from inception to June 30, 2015.

SELECTION CRITERIA

Randomized controlled trials of oral azathioprine or 6-mercaptopurine compared to placebo or active therapy involving adult patients (> 18 years) with quiescent Crohn's disease were considered for inclusion. Patients with surgically-induced remission were excluded.

DATA COLLECTION AND ANALYSIS

At least two authors independently extracted data and assessed study quality using the Cochrane risk of bias tool. For dichotomous outcomes, we calculated the risk ratio (RR) and corresponding 95% confidence interval (CI). The primary outcomes was maintenance of remission. Secondary outcomes included steroid sparing, adverse events, withdrawals due to adverse events and serious adverse events. All data were analyzed on an intention-to-treat basis. The overall quality of the evidence supporting the primary outcome and selected secondary outcomes was assessed using the GRADE criteria.

MAIN RESULTS

Eleven studies (881 participants) were included. Comparisons included AZA versus placebo (7 studies, 532 participants), AZA or 6-MP versus mesalazine or sulfasalazine (2 studies, 166 participants), AZA versus budesonide (1 study, 77 participants), AZA and infliximab versus infliximab (1 study, 36 patients), 6-MP versus methotrexate (1 study, 31 patients), and early AZA versus conventional management (1 study, 147 participants). Two studies were rated as low risk of bias. Three studies were rated as high risk of bias for being non-blinded. Six studies were rated as unclear risk of bias. A pooled analysis of six studies (489 participants) showed that AZA (1.0 to 2.5 mg/kg/day) was significantly superior to placebo for maintenance of remission over a 6 to 18 month period. Seventy-three per cent of patients in the AZA group maintained remission compared to 62% of placebo patients (RR 1.19, 95% CI 1.05 to 1.34). The number needed to treat for an additional beneficial outcome was nine. A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was low due to sparse data (327 events) and unclear risk of bias. A pooled analysis of two studies (166 participants) showed no statistically significant difference in the proportion of patients who maintained remission between AZA (1.0 to 2.5 mg/kg/day) or 6-MP (1.0 mg/day) and mesalazine (3 g/day) sulphasalazine (0.5 g/15 kg) therapy. Sixty-nine per cent of patients in the AZA/6-MP group maintained remission compared to 67% of mesalazine/sulphasalazine patients (RR 1.09, 95% CI 0.88 to 1.34). A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was low due to sparse data (113 events) and high or unclear risk of bias. One small study found AZA (2.0 to 2.5 mg/kg/day) to be superior to budesonide (6 to 9 mg/day) for maintenance of remission at one year. Seventy-six per cent (29/38) of AZA patients maintained remission compared to 46% (18/39) of budesonide patients (RR 1.65, 95% CI 1.13 to 2.42). GRADE indicated that the overall quality of the evidence supporting this outcome was low due to sparse data (47 events) and high risk of bias. One small study found no difference in maintenance of remission rates at one year between combination therapy with AZA (2.5 mg/kg) and infliximab (5 mg/kg every 8 weeks) compared to infliximab monotherapy. Eighty-one per cent (13/16) of patients in the combination therapy group maintained remission compared to 80% (16/20) of patients in the infliximab group (RR 1.02, 95% CI 0.74 to 1.40). GRADE indicated that the overall quality of the evidence supporting this outcome was very low due to very sparse data (29 events) and unclear risk of bias. One small study found no difference in maintenance of remission rates at one year between 6-MP (1 mg/day) and methotrexate (10 mg/week). Fifty per cent (8/16) of 6-MP patients maintained remission at one year compared to 53% (8/15) of methotrexate patients (RR 0.94, 95% CI 0.47 to 1.85). GRADE indicated that the overall quality of the evidence supporting this outcome was very low due to very sparse data (16 events) and high risk of bias. One study (147 participants) failed to show any significant benefit for early azathioprine treatment over a conventional management strategy. In the early azathioprine treatment group 67% (11-85%) of the trimesters were spent in remission compared to 56% (29-73%) in the conventional management group. AZA when compared to placebo had significantly increased risk of adverse events (RR 1.29, 95% CI 1.02 to 1.64), withdrawal due to adverse events (3.12, 95% CI 1.59 to 6.09) and serious adverse events (RR 2.45, 95% CI 1.22 to 4.90). AZA/6-MP also demonstrated a significantly higher risk of serious adverse events when compared to mesalazine or sulphasalazine (RR 9.37, 95% CI 1.84 to 47.7). AZA/6-MP did not differ significantly from other active therapies with respect to adverse event data. Common adverse events included pancreatitis, leukopenia, nausea, allergic reaction and infection.

AUTHORS' CONCLUSIONS

Low quality evidence suggests that AZA is more effective than placebo for maintenance of remission in Crohn's disease. Although AZA may be effective for maintenance of remission its use is limited by adverse effects. Low quality evidence suggests that AZA may be superior to budesonide for maintenance of remission but because of small study size and high risk of bias, this result should be interpreted with caution. No conclusions can be drawn from the other active comparator studies because of low and very low quality evidence. Adequately powered trials are needed to determine the comparative efficacy and safety of AZA and 6-MP compared to other active maintenance therapies. Further research is needed to assess the efficacy and safety of the use of AZA with infliximab and other biologics and to determine the optimal management strategy for patients quiescent Crohn's disease.

Optimal Endpoint of Therapy in IBD: An Update on Factors Determining a Successful Drug Withdrawal

Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory disorders, which require long term treatment to achieve remission and to prevent relapses and cancer. While current therapies are effective in most cases, they can have rare but serious side effects and are often associated with high costs. On the other hand, early discontinuation of an effective treatment may lead to a quick relapse and to complications at the restart of therapy. Therefore it is essential to determine the optimal duration of maintenance therapy, but clear guidelines are missing. The most important questions when deciding whether to continue or withdraw therapy in quiescent UC and CD patients are the efficacy of the continuous treatment to maintain remission in the long term, the frequency and severity of side effects, and the chance of relapse after discontinuation of therapy. This review summarizes the current knowledge on these topics with respect to 5-aminosalicylates, thiopurines, methotrexate, and biological therapies and collects information regarding when and in which specific patient groups, in the absence of risk factors, can withdrawal of therapy be considered without a high risk of relapse. Additionally, the particular aspect of colorectal cancer prevention by current therapies will also be discussed.

Withdrawal of long-term maintenance treatment with azathioprine tends to increase relapse risk in patients with Crohn's disease

BACKGROUND AND AIM

Many patients with quiescent Crohn's disease are maintained on long-term treatment with azathioprine (AZA), but controlled data are limited. We aimed to evaluate the efficacy of AZA therapy for more than 4 years to maintain clinical remission.

METHODS

We performed a randomized double-blind placebo-controlled AZA withdrawal trial with a follow-up period of 24 months. Patients had to have continuous AZA therapy ≥ 4 years without exacerbation of disease during the 12 months before enrollment, and a Crohn's disease activity index < 150 at baseline. Patients were randomized to continue on AZA or switch to placebo. The primary endpoint was time to clinical relapse during follow-up.

RESULTS

After inclusion of 52 patients, the trial was stopped prematurely due to slow recruitment. During the 2-year follow-up, clinical relapse occurred in 4 of 26 (15 %) patients on continued AZA and in 8 of 26 (31 %) patients on placebo. Time to clinical relapse averaged 22.3 months (95 % CI 20.6-24.0) on AZA and 19.2 months (95 % CI 16.4-22.1) on placebo (p = 0.20). According to life-table analysis, the proportion of patients in remission after 12 and 24 months was 96 ± 4 and 86 ± 7 % in patients receiving AZA versus 76 ± 8 and 68 ± 9 % in patients receiving placebo (month 12, p = 0.035; month 24, p = 0.30). A higher AZA dose at enrollment was an independent predictor for relapse (p < 0.05).

CONCLUSIONS

AZA withdrawal resulted in a significantly increased relapse risk after 1 year and a nonstatistically significant trend for relapse after 2 years. Our results are in line with previous observations.

Consensus guidelines of ECCO/ESPGHAN on the medical management of pediatric Crohn's disease

Children and adolescents with Crohn's disease (CD) present often with a more complicated disease course compared to adult patients. In addition, the potential impact of CD on growth, pubertal and emotional development of patients underlines the need for a specific management strategy of pediatric-onset CD. To develop the first evidenced based and consensus driven guidelines for pediatric-onset CD an expert panel of 33 IBD specialists was formed after an open call within the European Crohn's and Colitis Organisation and the European Society of Pediatric Gastroenterolog, Hepatology and Nutrition. The aim was to base on a thorough review of existing evidence a state of the art guidance on the medical treatment and long term management of children and adolescents with CD, with individualized treatment algorithms based on a benefit-risk analysis according to different clinical scenarios. In children and adolescents who did not have finished their growth, exclusive enteral nutrition (EEN) is the induction therapy of first choice due to its excellent safety profile, preferable over corticosteroids, which are equipotential to induce remission. The majority of patients with pediatric-onset CD require immunomodulator based maintenance therapy. The experts discuss several factors potentially predictive for poor disease outcome (such as severe perianal fistulizing disease, severe stricturing/penetrating disease, severe growth retardation, panenteric disease, persistent severe disease despite adequate induction therapy), which may incite to an anti-TNF-based top down approach. These guidelines are intended to give practical (whenever possible evidence-based) answers to (pediatric) gastroenterologists who take care of children and adolescents with CD; they are not meant to be a rule or legal standard, since many different clinical scenario exist requiring treatment strategies not covered by or different from these guidelines.

Ulcerative colitis: prevention of relapse

The clinical management of ulcerative colitis (UC) involves first treating the acute symptoms to induce remission, and then successfully maintaining it. Oral 5-aminosalicylic acids are safe and useful for maintaining remission in patients with UC. In terms of adherence, a once-daily form of 5-aminosalicylic acid is superior in maintaining remission as compared with split dosing. Patients at high risk of relapse may be candidates for treatment with thiopurines and/or biologics in the early stages of UC. Calcineurin inhibitors, such as cyclosporine and tacrolimus, are effective for severe, steroid-refractory UC patients. It is suggested that these patients use thiopurines as their maintenance therapy once they achieve remission with calcineurin inhibitors. Recent studies have confirmed that biologics are effective for inducing clinical and endoscopic remission of UC, and thus they may improve long-term prognosis of UC.

Azathioprine or 6-mercaptopurine for maintenance of remission in Crohn's disease

BACKGROUND

The therapeutic role of 6-mercaptopurine and azathioprine remains controversial due to their perceived relatively slow-acting effect and adverse effects. A meta-analysis was performed to evaluate the efficacy of these agents for the maintenance of remission of quiescent Crohn's disease.

OBJECTIVES

To assess the efficacy of azathioprine and 6-mercaptopurine for maintenance of remission in quiescent Crohn's disease.

SEARCH STRATEGY

Pertinent studies were selected using the MEDLINE data base (1966-May 1998), the Cochrane Controlled Trials Register, the Inflammatory Bowel Disease register, as well as abstracts from major gastrointestinal research meetings and references from published articles and review. This search strategy was updated (1998-May 2008) using the MEDLINE, EMBASE and International Pharmaceutical Abstracts databases, the Cochrane Central Register of Controlled Trials and the Cochrane IBD/FBD group Specialized Trials Register.

SELECTION CRITERIA

Randomized, double-blind, placebo-controlled trials of oral azathioprine or 6-mercaptopurine involving adult patients (> 18 years) with quiescent Crohn's disease.

DATA COLLECTION AND ANALYSIS

Data were extracted by three independent observers (EP, MC, LRS) based on the intention to treat principle. Peto odds ratios and 95% confidence intervals for maintenance of remission, steroid sparing, and withdrawals due to adverse effects were calculated. Numbers needed to treat or harm (NNT, NNH respectively) for the maintenance of remission, steroid sparing, and withdrawals due to adverse effects were also determined.

MAIN RESULTS

Seven trials of azathioprine therapy and one of 6-mercaptopurine were included in the review. Azathioprine and 6-mercaptopurine had a positive effect on maintaining remission. The Peto odds ratio (OR) for maintenance of remission with azathioprine was 2.32 (95% CI 1.55 to 3.49) with a NNT of 6. The Peto OR for maintenance of remission with 6-mercaptopurine was 3.32 (95% CI 1.40 to 7.87) with a of 4. Higher doses of azathioprine improved response. A steroid sparing effect with azathioprine was noted, with a Peto OR of 5.22 (95% CI 1.06 to 25.68) and NNT of 3 for quiescent disease. Withdrawals due to adverse events were more common in patients treated with azathioprine (Peto OR 3.74; 95% CI 1.48 to 9.45, NNH = 20) than with placebo.

AUTHORS' CONCLUSIONS

Azathioprine and 6-mercaptopurine are more effective than placebo for maintenance of remission in Crohn's disease. Higher response rates were obtained with azathioprine than 6-mercaptopurine. However, the one study evaluating 6-mercaptopurine used a relatively low dose of the drug. Future studies should look at the effect of higher doses of 6-mercaptopurine. There is weak evidence for a steroid sparing effect with azathioprine treatment.

Are we giving azathioprine too late? The case for early immunomodulation in inflammatory bowel disease

Inflammatory bowel disease (IBD) includes two entities, Crohn’s disease and ulcerative colitis. Both are chronic conditions with frequent complications and surgical procedures and a great impact on patient’s quality of life. The thiopurine antimetabolites azathioprine and 6-mercaptopurine are widely used in IBD patients. Current indications include maintenance therapy, steroid-dependant disease, fistula closure, prevention of infliximab immunogenicity and prevention of Crohn’s disease recurrence. Surprisingly, the wide use of immunosuppressants in the last decades has not decreased the need of surgery, probably because these treatments are introduced at too late stages in disease course. An earlier use of immunossupressants is now advocated by some authors. The rational includes: (1) failure to modify IBD natural history of present therapeutic approach, (2) demonstration that azathioprine can induce mucosal healing, a relevant prognostic factor for Crohn’s disease and ulcerative colitis, and (3) demonstration that early immunossupression has a very positive impact on pediatric, recently diagnosed Crohn’s disease patients. We are now awaiting the results of new studies, to clarify the contribution of azathioprine, as compared to infliximab (SONIC Study), and to demonstrate the usefulness of azathioprine in recently diagnosed adult Crohn’s disease patients (AZTEC study).