Fatal infectious mononucleosis: a severe complication in the treatment of Crohn's disease with azathioprine

Methods to avoid infections in patients with inflammatory bowel disease

Infections have been reported in patients with inflammatory bowel disease (IBD), especially in association with anti-inflammatory and immunomodulatory medications used to treat IBD. Unfortunately, there is a dearth of information on infectious complication risk in patients with IBD. This review describes infectious complications reported in patients with IBD and provides a framework for future studies to assess potential risk factors and incidence for infection. Recommendations are also provided for prevention of infection.

A randomized, double-blind, controlled withdrawal trial in Crohn's disease patients in long-term remission on azathioprine

BACKGROUND & AIMS

An open study reported that patients with Crohn's disease in remission who have taken azathioprine for longer than 3.5 years are at low risk of relapse when azathioprine is discontinued. To confirm this observation, we performed a multicenter, double-blind, noninferiority withdrawal study.

METHODS

Patients who were in clinical remission on azathioprine for > or = 42 months were randomized to continue azathioprine or to receive an equivalent placebo for 18 months. The primary end point was clinical relapse at 18 months.

RESULTS

Forty patients were randomly assigned to receive azathioprine and 43 to receive placebo. Characteristics of patients at entry were similar in the 2 study groups. At 18 months, 3 patients had a relapse in the azathioprine group, and 9 had a relapse in the placebo group. Kaplan-Meier estimates of the relapse rate at 18 months were 8% +/- 4% and 21% +/- 6%, respectively. The hypothesis that placebo was inferior to azathioprine was not rejected (P = .195). Among the baseline variables, C-reactive protein level > 20 mg/L, time without steroids < 50 months, and hemoglobin level < 12 g/dL were found to be predictive of relapse in the multivariate analysis.

CONCLUSIONS

This study shows that azathioprine withdrawal is not equivalent to continued therapy with azathioprine for maintenance of remission in patients with Crohn's disease who have been in remission on azathioprine for > or = 3.5 years. Thus, azathioprine maintenance therapy should be continued beyond 3.5 years.

[Opportunistic infections in patients with inflammatory bowel disease undergoing immunosuppressive therapy]

Immunosuppressive agents (azathioprine, methotrexate) are increasingly being used in the treatment of inflammatory bowel disease. The use of immunosuppressive agents is associated with a greater risk of opportunistic infections, the most frequent of which are those caused by cytomegalovirus and varicella zoster virus. We present four cases of opportunistic infections due to Herpesviruses in patients undergoing immunosuppressive treatment with azathioprine for Crohn's disease. We also review the literature published on this topic. Two patients presented cutaneous varicella complicated by pneumonia and esophagitis respectively, one patient had cutaneous herpes zoster and the other had fatal pneumonia possibly caused by the Herpesvirus. In the first three the clinical course of the infection was favorable after withdrawing immunosuppressant treatment and initiating treatment with aziclovir. In patients Crohn's disease azathioprine treatment increases the risk of opportunistic infection by Herpesvirus. However, in the absence of other factors that increase immunosuppression, these infections usually have a benign course with specific antiviral therapy.

Epstein-Barr virus-positive lymphoma in patients with inflammatory bowel disease treated with azathioprine or 6-mercaptopurine

BACKGROUND & AIMS

The use of azathioprine and 6-mercaptopurine for inflammatory bowel disease increased in the early 1990s. We sought to determine the effect of this change in therapy on the risk of lymphoma in patients with inflammatory bowel disease.

METHODS

All patients with inflammatory bowel disease at a single tertiary care medical center who developed lymphoma between 1985-2000 were identified and the pathologic features of the lymphoma including presence of Epstein- Barr virus were determined. The patients were divided into two 8-year periods (1985-1992, 1993-2000) corresponding with the introduction of azathioprine and 6-mercaptopurine in 1993.

RESULTS

Eighteen patients with lymphoma were identified, 6 between 1985-1992 and 12 between 1993-2000. Six of 18 lymphomas occurred in patients treated with azathioprine or 6-mercaptopurine, all between 1993-2000. Seven patients developed Epstein-Barr virus-positive lymphoma (1 from 1985-1992, 6 from 1993-2000). Five of 7 Epstein-Barr virus-positive lymphomas occurred in patients treated with azathioprine or 6-mercaptopurine compared with 1 of 11 Epstein-Barr virus-negative lymphomas (P = 0.01). Approximately 1200 patients with inflammatory bowel disease were treated with these agents between 1993-2000.

CONCLUSIONS

Treatment of inflammatory bowel disease with azathioprine or 6-mercaptopurine appears to be associated with a small increased risk of Epstein-Barr virus-positive lymphoma.

Sequential group trial to determine gastrointestinal site of absorption and systemic exposure of azathioprine

Azathioprine (AZA) is used in the treatment of patients with refractory inflammatory bowel disease; however, its use is limited because of systemic toxicity associated with long-term use. Ileocecal delivery of AZA might be advantageous if local intestinal therapeutic effects could be provided with decreased systemic side effects. Decreased cecal systemic absorption would allow higher dosages of AZA to be administered. A two-phase study was performed to compare the systemic exposure of AZA and 6-mercaptopurine (6-MP) following administration of AZA into the stomach, jejunum, and cecum and to compare the systemic exposure to AZA and 6-MP following administration of three different dosages of AZA into the cecum. In phase I, six healthy male volunteers received three 50 mg sequential doses of AZA via an oral tube directly placed into the stomach, jejunum, and cecum, respectively. In phase II, six healthy male volunteers received three different dosages (50, 300, 600 mg of AZA) into the cecum. Plasma concentrations of AZA and 6-MP at various times were quantified and area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were determined. No significant differences in the AUC of AZA were seen at the different sites. The AUC of 6-MP following administration of AZA into the jejunum (67.0 +/- 30.1 ng x hr/ml) was higher compared to the stomach (39.9 +/- 38.1 ng/hr/ml) and cecum (29.2 +/- 10.9 ng x hr/ml). Jejunal absorption was 68% higher than absorption from the stomach and 129% higher than that of the cecum. Gastric absorption was 27% higher than that of the cecum. Increased dosages given into the cecum resulted in increased AUCs of AZA and 6-MP. The AUCs of AZA following 50, 300, and 600 mg dosages were 16.9 +/- 7.4, 52.3 +/- 67.2, and 132 +/- 151 ng x hr/ml, respectively, and the AUCs of 6-MP were 22.2 +/- 14.9, 63.4 +/- 50.6, and 104 +/- 115 ng x hr/ml, respectively. Systemic exposure to 6-MP is reduced following administration of AZA into the cecum, most likely secondary to reduced absorption of 6-MP from the colon. Higher dosages of AZA presented to the cecum do result in increased systemic absorption, but may still allow more drug to be administered with less toxicity than the same dose received orally.

Immunosuppressors for inflammatory bowel disease: how long is long enough?

Immunosuppressors used in inflammatory bowel disease (IBD) are useful in refractory, chronic, active, steroid-dependent, or steroid-resistant IBD, but do not provide a permanent cure for IBD, their effect being only temporary. Only azathioprine and methotrexate are currently prescribed in the long term for IBD. The question of how long immunosuppressors should be given once remission has been induced and steroids discontinued has not yet been answered.

Therapy for Crohn disease

Medical therapy for Crohn disease has advanced incrementally: Small, non-definitive controlled trials of mesalamine continue to be reported, but the results are not sufficient to change the conclusion of a large meta-analysis that shows only marginal benefit of mesalamine in Crohn disease. Low-dose, controlled ileal-release budesonide is not effective for preventing postoperative recurrence of Crohn disease. A loading dose of intravenous azathioprine does not accelerate the time to response in patients with steroid-treated Crohn disease; however, standard azathioprine may work more quickly than previously reported. Mycophenolate mofetil may be therapeutically equivalent to azathioprine for active Crohn disease. There is a trend toward benefit of oral methotrexate (15 mg/wk) for active Crohn disease, and there is no significant difference in the blood concentrations of methotrexate in patients with inflammatory bowel disease who receive methotrexate (15 or 25 mg weekly) administered subcutaneously. Results in a pilot study suggest that tacrolimus may close perianal fistulas in patients with Crohn disease. The anti-tumor necrosis factor antibody infliximab is effective in closing perianal and enterocutaneous fistulas and in maintaining remission in patients with Crohn disease. Infliximab also leads to endoscopic and histologic remission. There is a trend toward benefit of subcutaneous recombinant interleukin-11 for active Crohn disease. Two pilot studies have shown that thalidomide may be of benefit in patients with refractory Crohn disease.

Safety of corticosteroids and immunosuppressive agents in ulcerative colitis

For many years, corticosteroids have been the mainstay for treating acute ulcerative colitis. In patients with refractory disease, immunosuppressive therapy may be indicated, including azathioprine or its metabolite 6-mercaptopurine, cyclosporin and possibly methotrexate. Their benefits in ulcerative colitis must be weighed up against their possible adverse effects, the availability of surgical cure for this condition, and the long-term risk of carcinoma complicating colitis that applies in patients with chronic extensive disease. Information about the safety of corticosteroids and immunosuppressive agents has accumulated as a result of their extensive use in inflammatory bowel disease, organ transplantation and various other disorders.