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Intravenous azathioprine in severe ulcerative colitis: a pilot study
THE AMERICAN JOURNAL OF GASTROENTEROLOGY © 2000 by Am. Coll. of Gastroenterology Published by Elsevier Science Inc.
Vol. 95, No. 12, 2000 ISSN 0002-9270/00/$20.00 PII S0002-9270(00)02155-9
Intravenous Azathioprine in Severe Ulcerative Colitis: A Pilot Study Uma Mahadevan, M.D., William J. Tremaine, M.D., Therese Johnson, R.N., B.S.N., M. Gennett Pike, B.S., Dennis C. Mays, Ph.D., James J. Lipsky, M.D., and William J. Sandborn, M.D. Division of Gastroenterology and Hepatology, University of California, San Francisco, San Francisco, California; Division of Gastroenterology and Hepatology, Clinical Pharmacology Unit, Mayo Clinic, Rochester, Minnesota
OBJECTIVE: Azathioprine use in acute ulcerative colitis has been limited by its perceived long onset of action. The aim of this study was to determine the safety and clinical effect of an i.v. loading dose of azathioprine in the setting of severe steroid refractory ulcerative colitis. METHODS: Nine hospitalized patients with severe steroid refractory ulcerative colitis were enrolled. Patients 1–3 received 20 mg/kg i.v. azathioprine over 36 h. Patients 4 – 6 received 40 mg/kg i.v. azathioprine over 36 h. Patients 7–9 received 40 mg/kg i.v. azathioprine as three 8-h infusions over 3 days. Clinical remission was defined as steroid withdrawal and an Ulcerative Colitis Disease Activity Index score of 0. The Inflammatory Bowel Disease Questionnaire was obtained at each visit. White blood cell concentrations and erthyrocyte concentrations of 6-thioguanine were obtained. RESULTS: Five of nine patients (56%) had a response and avoided colectomy. Three of nine patients (33%) met the definition for clinical remission. Response was seen within 4 wk. The mean 6-thioguanine concentration for those five patients at 12 wk after infusion was 148.2 pmol/8 ⫻ 108. Two patients had transient leukopenia and one had transient hepatotoxicity. CONCLUSIONS: Intravenous azathioprine appears to be safe and of clinical benefit in inducing response and avoiding colectomy in severe steroid refractory ulcerative colitis. Data from an i.v. azathioprine trial in Crohn’s disease suggests oral dosing alone may obtain the same results. The role of oral dosing alone in severe ulcerative colitis and the role of azathioprine metabolite levels in monitoring efficacy should be investigated further. (Am J Gastroenterol 2000; 95:3463–3468. © 2000 by Am. Coll. of Gastroenterology)
INTRODUCTION The medical armamentarium for severe ulcerative colitis (UC) is limited. Approximately 29% of patients hospitalized for severe UC will undergo a colectomy on that admission (1). Intravenous (i.v.) corticosteroids have been the mainstay of treatment in severe colitis (2). In 1994, a randomized
placebo-controlled trial demonstrated that i.v. cyclosporine led to clinical remission in 82% of patients who had already failed i.v. corticosteroids (3). However, only 45% of those patients avoided colectomy at 6 months (4). Overlapping therapy with i.v. corticosteroids, cyclosporine, and azathioprine (AZA) for 4 – 6 months with a steroid and cyclosporine taper has reduced the colectomy rate, but has resulted in opportunistic infections and death in some patients (5–7). This experience has tempered the enthusiasm for use of i.v. cyclosporine in these patients. In UC, the efficacy of AZA for the indications of steroid sparing, maintenance of remission, and possibly chronic active disease are established by placebo-controlled trials (8 –12). The safety profile of this drug and a related compound 6-mercaptopurine (6-MP) with respect to neoplasia (13), bone marrow toxicity (14), and hepatotoxicity (15) is also relatively well established. However, both drugs have had limited use in the setting of acute colitis because of a purported delay in the onset of action. A meta-analysis of all placebo-controlled trials of AZA/6-MP in Crohn’s disease observed consistent clinical benefit only after 17 wk or more of therapy (16), confirming a prior observation in patients with Crohn’s disease that 6-MP required a mean of 3 months for clinical response (17). In 1995, a pilot study suggested that an i.v. loading dose of AZA decreased the time to response in patients with Crohn’s disease. Seven of 13 fistulas in six patients closed and four of six patients with nonfistulous disease achieved clinical remission. This study also found that the improvement occurred within 4 wk and that peak concentrations of AZA metabolites occurred within 3 days (18). On the basis of these results, a pilot study of i.v. AZA loading in UC was undertaken. The aim of this study was to use an i.v. pretreatment of AZA before initiating an oral dose of 2.0 mg/kg/day of AZA to decrease the time to clinical response and to decrease the time required to reach a steady-state concentration of red blood cells of 6-thioguanine (6-TGN), the putative active metabolite of AZA and 6-MP. During the course of this preliminary study in UC, the results of a multicenter placebo controlled trial of i.v. AZA loading in patients with steroid-dependent Crohn’s disease became
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available showing no difference between the i.v. AZAloaded group and the placebo group with respect to achievement of clinical remission (19). However, the results of this pilot study in UC and the levels of 6-TGN achieved are intriguing and are presented here.
levels normalized. At that point, the AZA was reintroduced at half the dose used at the time of discontinuation. In some cases, when toxicity occurred after the i.v. loading dose, AZA was reintroduced at the full oral dose. Serum chemistry or complete blood cell counts were then obtained weekly for 4 wk and then per protocol (discussed later).
MATERIALS AND METHODS
Concomitant Drug Therapy Patients received i.v. methylprednisolone during their hospitalization and were converted to oral prednisone at discharge. The steroid dose (methylprednisolone or prednisone) was continued for 1 wk at 40 mg/day and then tapered by 5 mg/wk over 7 wk. Concomitant immunomodulators were not permitted and there was an interval of at least 3 months (6-MP, AZA, anti-tumor necrosis factor-␣ antibody, IL-10), 2 months (methotrexate), or 1 month (cyclosporin or FK506) between previous therapy and i.v. AZA. Oral mesalamine and topical mesalamine or steroids were continued at a stable dose. Other non-UC medications were also continued at prestudy doses. Parenteral and enteral nutrition (elemental and semielemental diets) were discontinued at discharge from the hospital.
Patients From September 1997 to April 1999, nine patients with severe steroid refractory UC were treated with an i.v. loading dose of AZA followed by an oral dose of 2.0 mg/kg/d of AZA in a single-center open label protocol of 12 wk duration. All patients gave written consent. The study was approved by the institutional review board of the Mayo Clinic. The subjects were hospital inpatients with active steroid refractory UC with an Ulcerative Colitis Disease Activity Index (UCDAI) score of 5–12 points, who had received and failed i.v. methylprednisolone ⱖ40 mg/day or its equivalent for ⱖ7 days. The patients were ⱖ18 yr of age with established UC confirmed by histology and endoscopy. Patients were excluded if they had received other investigational drugs within 30 days, had a colostomy, an active infection, a fixed symptomatic stenosis or obstruction, a history of colonic dysplasia, or any malignancy in the past 5 yr. Patients with suspected intolerance of AZA/6-MP, low or intermediate levels of red blood cell (RBC) thiopurine methyltransferase (TPMT) enzyme activity, renal disease, hepatic dysfunction, or allopurinol within 1 wk of the study date were also excluded. AZA Therapy Hospitalized patients who met entry criteria were pretreated with an open label i.v. loading dose of commercially available AZA (Glaxo-Wellcome, Research Triangle Park, NC). Patients 1–3 received 20 mg/kg as a 36-h infusion; patients 4 – 6 received 40 mg/kg as a 36-h infusion; and patients 7–9 received 40 mg/kg as three 8-h infusions over 3 days. Treatment with commercially available oral AZA (2.0 mg/ kg) was initiated the day after completion of the i.v. AZA loading dose. Dosage adjustment was not performed in response to a lack of efficacy but it was allowed according to a standardized protocol for hepatotoxicity, leukopenia, thrombocytopenia, infection, pancreatitis, malignancy, and other side effects. Hepatotoxicity was defined as an increase in serum AST to a level more than five times the upper limit of normal or an increase in the alkaline phosphatase to a level that was more than three times the upper limit of normal. Leukopenia was defined as a total white blood cell count below 3.0 ⫻ 109/L. Thrombocytopenia was defined as a decrease in the total platelet count below 100 ⫻ 109/L. If hepatotoxicity, leukopenia, or thrombocytopenia occurred, then AZA was discontinued and serum chemistry or a complete blood count was obtained twice weekly until the white blood cell count, platelets, AST, or alkaline phosphatase
Measurements of Clinical Disease Activity Procedures performed at all visits included physical examination, UCDAI, completion of the inflammatory bowel disease questionnaire (IBDQ) regarding quality of life, clinical laboratory assessments, and flexible sigmoidoscopy with endoscopic disease activity assessment. The UCDAI was developed from Truelove and Witts’ criteria for mild, moderate, and severe UC (20) and the criteria from Baron et al. (21) for grading the mucosal appearance. The variables used to calculate the UCDAI were stool frequency and rectal bleeding from the patient’s diary, mucosal appearance from the flexible sigmoidoscopy, as well as a global assessment (physician’s overall impression based on the diary, physical examination, flexible sigmoidoscopy, and laboratory data). This 13-point index (0 –12) has been used previously to assess disease activity in UC by other investigators (22, 23). Toxicity Monitoring Patients were monitored for clinical evidence of AZA toxicity including hepatotoxicity, myelotoxicity, pancreatitis, malignancy, opportunistic infection, and AZA drug fever, rash, arthralgias, and nausea. A complete blood count with differential and liver function tests were obtained at study entry, at completion of infusion of i.v. AZA, and at wk 1, 2, 3, 4, 6, 8, 10, and 12. Blood for measurement of TPMT enzyme activity was obtained before receiving an AZA dose. TPMT activity has a trimodal distribution in the general population (24). Low TPMT activity (⬍5.0 U/ml RBC) occurs in 0.3% of the population; intermediate TPMT activity (5.0 –13.7 U/ml RBC) occurs at a frequency of 11.1%; and high or normal TPMT activity (13.8 –25.1 U/ml RBC) occurs at a frequency of 88.6%. All patients had to have normal TPMT activity (ⱖ13.8 U/ml) to be included in the study. Blood was obtained for measurement of RBC 6-TGN
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Intravenous AZA in Severe Ulcerative Colitis
Table 1. Baseline Patient Characteristics Characteristics Gender Mean age (yr) Mean weight (kg) Tobacco use Duration of disease (mos) Duration of current exacerbation (mos) Extent of disease Extraintestinal manifestations Mean TPMT (U/ml RBC) Mean UCDAI Mean IBDQ Prior medications (No. of patients)
Data 8 men; 1 woman 44.4 (range, 24–70) 78.6 (range, 53.3–122.1) 7 nonsmokers; 2 former smokers 37.1 (range, 2–108) 2 (range, 1–4) 2 splenic flexure; 7 pancolitis 1 arthritis 18.0 (range, 15.7–22.2) 9 (range, 8–12) 129.4 (range, 95–184) 9 corticosteroids; 9 mesalamine; 2 transdermal nicotine; 1 cyclosporine; 1 metronidazole; 1 ciprofloxacin; 9 corticosteroids; 5 mesalamine; 1 metronidazole; 1 heparin
concentrations before commencing the study, immediately after the last infusion of AZA, and at wk 1, 2, 3, 4, 6, 8, 10, and 12 just before the daily oral AZA dose (25).
RESULTS Nine patients were enrolled in the trial. Patients 1–3 received 20 mg/kg as a 36-h infusion; patients 4 – 6 received 40 mg/kg as a 36-h infusion; and patients 7–9 received 40
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mg/kg as three 8-h infusions over 3 days. Baseline characteristics of the nine patients are outlined in Table 1. Five patients completed the scheduled 12 wk of therapy. Four patients withdrew to undergo colectomy. One patient who achieved remission had received previous therapy with cyclosporine. The remaining eight patients had no previous immunomodulator therapy. Clinical Efficacy Three of the nine patients achieved clinical remission as defined by cessation of steroids and a UCDAI of 0. Two patients achieved a clinical response with withdrawal of steroids and a decrease in the UCDAI to 1 and 3, respectively. All five patients had an IBDQ ⬎170 —a score generally considered to indicate remission (26). For the five patients who did not go to surgery, the improvement in the IBDQ during 12 wk was a mean increase of 67.6 points (range, 32–116). The mean time for the IBDQ to increase ⬎170 was 5 wk (range, 0 – 8). The mean decrease in the UCDAI was 8.2 points (range, 5–11). The UCDAI reached 0 at wk 8 for Patient 8 and at wk 12 for Patients 1 and 9. The decrease in UCDAI scores began by 7 days after infusion in all five patients spared colectomy. Of the three patients who received a 20 mg/kg i.v. AZA loading dose, one attained clinical remission, one had a clinical response with steroid withdrawal and a UCDAI of 1, and one went to surgery within 4 days of receiving the loading dose. The evolution of endoscopic healing in Patient 1 over the 12 wk following the i.v. AZA is shown in Figure 1. Of the three patients who received a 40 mg/kg i.v. AZA
Figure 1. (A) The sigmoid colon of Patient 1 at entry into the trial. Ulcerations and friability are seen throughout. (B) The same patient at wk 4 after infusion of AZA. (C) Wk 8. (D) Wk 12. There is a healed scar seen at the site of previous ulceration.
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Figure 2. Individual patient erythrocyte 6-TGN concentrations after treatment with an i.v. AZA loading dose followed by 2.0 mg/kg/day oral AZA for 12 wk. The RBC 6-TGN concentrations were obtained at baseline, immediately after infusion, and at 1, 2, 3, 4, 8, 10, and 12 wk after infusion.
loading dose, two went to surgery at 12 and 18 days, respectively. The third patient achieved a clinical response with steroid withdrawal and a UCDAI of 3. Three patients received 40 mg/kg i.v. AZA as three 8-h infusions. Of these, two achieved clinical remission and one was referred for surgery at 31 days after infusion. However, this latter patient was not operated on for an additional 2 months due to a deep venous thrombosis. AZA Metabolism The mean baseline TPMT for the nine patients was 18 U/ml RBC. Patients achieved a mean RBC 6-TGN concentration of 120.9 pmol/8 ⫻ 108 RBC (range, 52–206) after the 36-h infusion. The mean RBC 6-TGN concentration at wk 12 was 148.2 (range, 108 –244) for the five patients in clinical remission/response. Patients who received a 20 mg/kg i.v. loading dose had a mean postinfusion RBC 6-TGN concentration of 81.3. Those who received 40 mg/kg had a mean of 126.3. Finally, those who received 40 mg/kg as three 8-h infusions had a mean postinfusion RBC 6-TGN concentration of 155. Figure 2 demonstrates the individual RBC 6-TGN concentrations for each patient over the 12-wk period. Adverse Events Three of the nine patients experienced an adverse event. One patient, who eventually achieved a clinical response, experienced hepatotoxicity 7 days after -infusion and her AZA was immediately discontinued. Her peak liver function tests, which occurred on day 7 after infusion, were an AST 292, ALT 695, and alkaline phosphatase 474. The aminotransferases normalized during 1 wk and she restarted her AZA 11 days after initially discontinuing it. The dose was the same as before the elevation of liver enzymes (125 mg/day or 2.0 mg/kg/day). She had no further problems with hepatotoxicity.
The mean initial WBC concentration was 11.8 ⫻ 109/L. Figure 3 demonstrates the change in the individual WBC concentrations of each patient over the 12-wk period. Two patients experienced leukopenia during the course of the trial. The first patient discontinued his AZA 7 days after infusion when his WBC count dropped to 2.9 ⫻ 109/L. It was restarted the next day when his WBC normalized. Five days later, he had a WBC nadir of 2.3 ⫻ 109/L and the medication was discontinued. The patient received GCSF (Neupogen-Amgen, Thousand Oaks, CA) with a recovery of his WBC count to 3.8 ⫻ 109/L and was taken to surgery the next day. The second patient developed leukopenia 7 days after infusion. His nadir WBC count was 2.7 ⫻ 109/L. His AZA dose was withheld for 5 days and his WBC count increased to 4.1 ⫻ 109/L. AZA was restarted at the same dose of 150 mg/day (2.0 mg/kg/day) and there were no further episodes of leukopenia. He achieved clinical response with steroid withdrawal at 12 wk and a UCDAI of 3.
DISCUSSION Five of nine hospitalized patients (56%) with severe steroid refractory UC administered an i.v. loading dose of AZA avoided colectomy. All five had complete steroid withdrawal by wk 12. Three (33%) met the definition of clinical remission at 12 wk, with steroid withdrawal and a UCDAI of 0. The two patients who did not undergo colectomy, yet did not attain full clinical remission had a reduction of their AZA dose secondary to toxicity. It is conceivable that their 12-wk UCDAI would have reached 0 if they had tolerated continuous full-dose therapy. A randomized trial by Sandborn et al. (19) in 1999 demonstrated that i.v. AZA does not decrease the time to response or increase the response rate over oral AZA alone in the setting of Crohn’s disease. This study also suggested
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Figure 3. Individual patient WBC concentrations after treatment with i.v. AZA loading dose followed by 2.0 mg/kg/day oral AZA for 12 wk. The WBC concentrations were obtained at baseline, immediately after infusion, and at 1, 2, 3, 4, 8, 10, and 12 wk after infusion. Overall, there was a decrease in the WBC concentrations over the 12 wk, but there was no difference between the responders and nonresponders with respect to leukopenia.
that AZA works more rapidly than previously believed (16, 17). In our study, patients demonstrated decreasing UCDAI scores and increasing IBDQ scores by wk 2. By wk 4, the mean IBDQ had increased from a baseline mean of 129.4 – 174.5, above the 170-point minimum used to define clinical remission. The mean UCDAI at wk 4 had decreased from a mean of 9 –3.4 points; by wk 5 the mean was 1.8 points. This is consistent with the Crohn’s i.v. AZA trial, suggesting that AZA (oral or i.v.) demonstrates a significant effect by 2– 4 wk in UC as well as in Crohn’s disease. Although this is a small open-label trial, the 56% colectomy-sparing rate in patients who have failed i.v. corticosteroids is impressive. This suggests that AZA could have a role in the acute setting of severe UC. By extrapolation from the Crohn’s i.v. AZA trial, oral therapy with AZA alone may be adequate to achieve an early response in 2– 4 wk. A study by Casson et al. (27) suggested that a low dose of i.v. AZA was beneficial in fulminant colitis. Three patients received i.v. AZA for 5–7 days. Both a sustained response and a steroid reduction were achieved. Clinical response was associated with mucosal healing. They suggested that the rapid response might reflect immunological differences between chronic severe disease and the acute changes of toxic dilatation. The i.v. doses of AZA were 2.3–2.6 mg/kg/day, which is equivalent to the standard oral dosing of 5.0 mg/ kg/day. Steady-state concentrations of RBC 6-TGN were reached at the end of 1 wk in the nine patients studied. Erythrocyte 6-TGN levels have been shown to have an inverse correlation with the Harvey-Bradshaw Index in patients with Crohn’s disease (28). A study by Dubinsky et al. (29) found that 65% of patients who had induction of remission of Crohn’s disease while on 6-MP had a 6-TGN concentration
⬎230 pmol/8 ⫻ 108 RBC. We used a different assay for RBC 6-TGN (25) than that used by Cuffari and Dubinsky. A conversion factor of 1.6 can be used to convert the RBC 6-TGN concentration determined by our assay methodology to equivalent values for the assay used by Prometheus Laboratories (San Diego, CA) and by Cuffari and Dubinsky. The correlation coefficient between the two assays is 99%. (WJ Sandborn, unpublished data). Of the five patients in our study who responded, the mean RBC 6-TGN concentration was 148.2 pmol/8 ⫻ 108 RBC (range, 108 –244). This would be equivalent to a mean concentration of 237.1 pmol/ 8 ⫻ 108 using the Prometheus Laboratories assay system. Two of the three patients who met the definition of remission had the equivalent of ⬎230 pmol/8 ⫻ 108 RBCs, although both patients who responded but did not have complete remission had a concentration ⬍230. The clinical utility of measuring metabolite levels of AZA warrants further study. The mean WBC count decreased from 11.8 ⫻ 109/L to 6.3 ⫻ 109/L. As in the i.v. AZA Crohn’s trial, remission was not associated with leukopenia. TPMT activity was in the homozygous or normal range in all patients. Although no serious adverse events occurred, two patients did have transient leukopenia and one had transient hepatotoxicity. These adverse events resolved quickly and the two patients who did not require surgery for lack of response were able to restart AZA at the same dosage without further toxicity. Patients with heterozygous or homozygous low TPMT activity were not included in the trial. The safety of i.v. AZA in these patients is not known. In conclusion, i.v. AZA is safe and appears to be of benefit in inducing remission and avoiding colectomy in patients with severe steroid refractory UC. Extrapolation
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from the i.v. AZA Crohn’s trial suggests that oral dosing at 2 mg/kg/day could have an equivalent result. The actual avoidance of colectomy in 56% of patients who failed i.v. steroids suggests a possible role for AZA, oral or i.v., in the acute setting. It appears that AZA is safer than cyclosporine and can be used for long-term maintenance of remission. Further studies are needed to determine the efficacy of oral or low dose i.v. AZA in severe UC, as well as for the role of TPMT and the metabolite 6-TGN in determining safety and optimizing response.
ACKNOWLEDGMENTS This study was funded in part by the Mayo Foundation for Research and Education. Intravenous and oral azathioprine was provided by Glaxo Wellcome (Research Triangle Park, NC). Reprint requests and correspondence: William J. Sandborn, M.D., Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905. Received Mar. 21, 2000; accepted July 24, 2000.
REFERENCES 1. Travis SP, Farrant JM, Ricketts C, et al. Predicting outcome in severe ulcerative colitis. Gut 1996;38:905–10. 2. Truelove SC, Jewell DP. Intensive intravenous regimen for severe attacks of ulcerative colitis. Lancet 1974;1:1067–70. 3. Lichtiger S, Present DH, Kornbluth A, et al. Cyclosporine in severe ulcerative colitis refractory to steroid therapy (comments). N Engl J Med 1994;330:1841–5. 4. Kornbluth AL, S. Present, D. Hanauer, S. Long-term results of oral cyclosporin in patients with severe ulcerative colitis: A double blind, randomized, multi-center trial. Gastroenterology 1994;106:A714. 5. Fernandez-Banares F, Bertran X, Esteve-Comas M, et al. AZA is useful in maintaining long-term remission induced by intravenous cyclosporine in steroid-refractory severe ulcerative colitis. Am J Gastroenterol 1996;91:2498 –9. 6. Cohen RD, Brodsky AL, Hanauer SB. A comparison of the quality of life in patients with severe ulcerative colitis after total colectomy versus medical treatment with intravenous cyclosporin. Inflam Bowel Dis 1999;5:1–10. 7. Sternthal M, George J, Kornbluth A, et al. Toxicity associated with the use of cyclosporin in patients with inflammatory bowel disease (IBD). Gastroenterology 1997;110:A1019. 8. Jewell DP, Truelove SC. AZA in ulcerative colitis: Final report on controlled therapeutic trial. BMJ 1974;4:627–30. 9. Rosenberg JL, Wall AJ, Levin B, et al. A controlled trial of AZA in the management of chronic ulcerative colitis. Gastroenterology 1975;69:96 –9. 10. Kirk AP, Lennard-Jones JE. Controlled trial of AZA in chronic ulcerative colitis. BMJ 1982;284:1291–2. 11. Caprilli R, Carratu R, Babbini M. Double-blind comparison of the effectiveness of AZA and sulfasalazine in idiopathic proctocolitis. Preliminary report. Am J Dig Dis 1975;20:115–20.
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12. Hawthorne AB, Logan RF, Hawkey CJ, et al. Randomized controlled trial of AZA withdrawal in ulcerative colitis. BMJ 1992;305:20 –2. 13. Connell WR, Kamm MA, Dickson M, et al. Long-term neoplasia risk after AZA treatment in inflammatory bowel disease. Lancet 1994;343:1249 –52. 14. Connell WR, Kamm MA, Ritchie JK, et al. Bone marrow toxicity caused by AZA in inflammatory bowel disease: 27 years of experience. Gut 1993;34:1081–5. 15. Present DH, Meltzer SJ, Krumholz MP, et al. 6-Mercaptopurine in the management of inflammatory bowel disease: Shortand long-term toxicity. Ann Intern Med 1989;111:641–9. 16. Pearson DC, May GR, Fick GH, et al. AZA and 6-mercaptopurine in Crohn disease. A meta-analysis. Ann Intern Med 1995;123:132– 42. 17. Present DH, Korelitz BI, Wisch N, et al. Treatment of Crohns disease with 6-mercaptopurine. A long-term, randomized, double-blind study. N Engl J Med 1980;302:981–7. 18. Sandborn WJ, Van OE, Zins BJ, et al. An intravenous loading dose of AZA decreases the time to response in patients with Crohns disease. Gastroenterology 1995;109:1808 –17. 19. Sandborn WJ, Tremaine WJ, Wolf DC, et al. Lack of effect of intravenous administration on time to respond to AZA for steroid-treated Crohns disease. North American AZA Study Group. Gastroenterology 1999;117:527–35. 20. Truelove SC, Witts LJ. Cortisone in ulcerative colitis: Final report on a therapeutic trial. BMJ 1955;2:1041– 8. 21. Baron J, Connell A, Lennard Jones JE. Variation between observers in describing mucosal appearances in proctocolitis. BMJ 1964;1:89 –92. 22. Sutherland LR, Martin F, Greer S, et al. 5-Aminosalicylic acid enema in the treatment of distal ulcerative colitis, proctosigmoiditis, and proctitis. Gastroenterology 1987;92:1894 – 8. 23. Schroeder KW, Tremaine WJ, Ilstrup DM. Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study. N Engl J Med 1987;317: 1625–9. 24. Weinshilboum RM, Sladek SL. Mercaptopurine pharmacogenetics: Monogenic inheritance of erythrocyte thiopurine methyltransferase activity. Am J Hum Genet 1980;32:651– 62. 25. Erdmann GR, France LA, Bostrom BC, et al. A reversed phase high performance liquid chromatography approach in determining total red blood cell concentrations of 6-thioguanine, 6-mercaptopurine, methylthioguanine, and methylmercaptopurine in a patient receiving thiopurine therapy. Biomed Chromatogr 1990;4:47–51. 26. Irvine EJ, Feagan B, Rochon J, et al. Quality of life: A valid and reliable measure of therapeutic efficacy in the treatment of inflammatory bowel disease. Canadian Crohns Relapse Prevention Trial Study Group. Gastroenterology 1994;106:287– 96. 27. Casson DH, Davies SE, Thomson MA, et al. Low-dose intravenous AZA may be effective in the management of acute fulminant colitis complicating inflammatory bowel disease. Aliment Pharmacol Ther 1999;13:891–5. 28. Cuffari C, Theoret Y, Latour S, et al. 6-Mercaptopurine metabolism in Crohns disease: Correlation with efficacy and toxicity. Gut 1996;39:401– 6. 29. Dubinsky MC, Lamothe S, Yang HY, et al. Pharmacogenomics and metabolite measurement for 6-mercaptopurine therapy in inflammatory bowel disease. Gastroenterology 2000;118: 705–13.
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Intravenous Azathioprine in Severe Ulcerative Colitis: A Pilot Study Uma Mahadevan, M.D., William J. Tremaine, M.D., Therese Johnson, R.N., B.S.N., M. Gennett Pike, B.S., Dennis C. Mays, Ph.D., James J. Lipsky, M.D., and William J. Sandborn, M.D. Division of Gastroenterology and Hepatology, University of California, San Francisco, San Francisco, California; Division of Gastroenterology and Hepatology, Clinical Pharmacology Unit, Mayo Clinic, Rochester, Minnesota
OBJECTIVE: Azathioprine use in acute ulcerative colitis has been limited by its perceived long onset of action. The aim of this study was to determine the safety and clinical effect of an i.v. loading dose of azathioprine in the setting of severe steroid refractory ulcerative colitis. METHODS: Nine hospitalized patients with severe steroid refractory ulcerative colitis were enrolled. Patients 1–3 received 20 mg/kg i.v. azathioprine over 36 h. Patients 4 – 6 received 40 mg/kg i.v. azathioprine over 36 h. Patients 7–9 received 40 mg/kg i.v. azathioprine as three 8-h infusions over 3 days. Clinical remission was defined as steroid withdrawal and an Ulcerative Colitis Disease Activity Index score of 0. The Inflammatory Bowel Disease Questionnaire was obtained at each visit. White blood cell concentrations and erthyrocyte concentrations of 6-thioguanine were obtained. RESULTS: Five of nine patients (56%) had a response and avoided colectomy. Three of nine patients (33%) met the definition for clinical remission. Response was seen within 4 wk. The mean 6-thioguanine concentration for those five patients at 12 wk after infusion was 148.2 pmol/8 ⫻ 108. Two patients had transient leukopenia and one had transient hepatotoxicity. CONCLUSIONS: Intravenous azathioprine appears to be safe and of clinical benefit in inducing response and avoiding colectomy in severe steroid refractory ulcerative colitis. Data from an i.v. azathioprine trial in Crohn’s disease suggests oral dosing alone may obtain the same results. The role of oral dosing alone in severe ulcerative colitis and the role of azathioprine metabolite levels in monitoring efficacy should be investigated further. (Am J Gastroenterol 2000; 95:3463–3468. © 2000 by Am. Coll. of Gastroenterology)
INTRODUCTION The medical armamentarium for severe ulcerative colitis (UC) is limited. Approximately 29% of patients hospitalized for severe UC will undergo a colectomy on that admission (1). Intravenous (i.v.) corticosteroids have been the mainstay of treatment in severe colitis (2). In 1994, a randomized
placebo-controlled trial demonstrated that i.v. cyclosporine led to clinical remission in 82% of patients who had already failed i.v. corticosteroids (3). However, only 45% of those patients avoided colectomy at 6 months (4). Overlapping therapy with i.v. corticosteroids, cyclosporine, and azathioprine (AZA) for 4 – 6 months with a steroid and cyclosporine taper has reduced the colectomy rate, but has resulted in opportunistic infections and death in some patients (5–7). This experience has tempered the enthusiasm for use of i.v. cyclosporine in these patients. In UC, the efficacy of AZA for the indications of steroid sparing, maintenance of remission, and possibly chronic active disease are established by placebo-controlled trials (8 –12). The safety profile of this drug and a related compound 6-mercaptopurine (6-MP) with respect to neoplasia (13), bone marrow toxicity (14), and hepatotoxicity (15) is also relatively well established. However, both drugs have had limited use in the setting of acute colitis because of a purported delay in the onset of action. A meta-analysis of all placebo-controlled trials of AZA/6-MP in Crohn’s disease observed consistent clinical benefit only after 17 wk or more of therapy (16), confirming a prior observation in patients with Crohn’s disease that 6-MP required a mean of 3 months for clinical response (17). In 1995, a pilot study suggested that an i.v. loading dose of AZA decreased the time to response in patients with Crohn’s disease. Seven of 13 fistulas in six patients closed and four of six patients with nonfistulous disease achieved clinical remission. This study also found that the improvement occurred within 4 wk and that peak concentrations of AZA metabolites occurred within 3 days (18). On the basis of these results, a pilot study of i.v. AZA loading in UC was undertaken. The aim of this study was to use an i.v. pretreatment of AZA before initiating an oral dose of 2.0 mg/kg/day of AZA to decrease the time to clinical response and to decrease the time required to reach a steady-state concentration of red blood cells of 6-thioguanine (6-TGN), the putative active metabolite of AZA and 6-MP. During the course of this preliminary study in UC, the results of a multicenter placebo controlled trial of i.v. AZA loading in patients with steroid-dependent Crohn’s disease became
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available showing no difference between the i.v. AZAloaded group and the placebo group with respect to achievement of clinical remission (19). However, the results of this pilot study in UC and the levels of 6-TGN achieved are intriguing and are presented here.
levels normalized. At that point, the AZA was reintroduced at half the dose used at the time of discontinuation. In some cases, when toxicity occurred after the i.v. loading dose, AZA was reintroduced at the full oral dose. Serum chemistry or complete blood cell counts were then obtained weekly for 4 wk and then per protocol (discussed later).
MATERIALS AND METHODS
Concomitant Drug Therapy Patients received i.v. methylprednisolone during their hospitalization and were converted to oral prednisone at discharge. The steroid dose (methylprednisolone or prednisone) was continued for 1 wk at 40 mg/day and then tapered by 5 mg/wk over 7 wk. Concomitant immunomodulators were not permitted and there was an interval of at least 3 months (6-MP, AZA, anti-tumor necrosis factor-␣ antibody, IL-10), 2 months (methotrexate), or 1 month (cyclosporin or FK506) between previous therapy and i.v. AZA. Oral mesalamine and topical mesalamine or steroids were continued at a stable dose. Other non-UC medications were also continued at prestudy doses. Parenteral and enteral nutrition (elemental and semielemental diets) were discontinued at discharge from the hospital.
Patients From September 1997 to April 1999, nine patients with severe steroid refractory UC were treated with an i.v. loading dose of AZA followed by an oral dose of 2.0 mg/kg/d of AZA in a single-center open label protocol of 12 wk duration. All patients gave written consent. The study was approved by the institutional review board of the Mayo Clinic. The subjects were hospital inpatients with active steroid refractory UC with an Ulcerative Colitis Disease Activity Index (UCDAI) score of 5–12 points, who had received and failed i.v. methylprednisolone ⱖ40 mg/day or its equivalent for ⱖ7 days. The patients were ⱖ18 yr of age with established UC confirmed by histology and endoscopy. Patients were excluded if they had received other investigational drugs within 30 days, had a colostomy, an active infection, a fixed symptomatic stenosis or obstruction, a history of colonic dysplasia, or any malignancy in the past 5 yr. Patients with suspected intolerance of AZA/6-MP, low or intermediate levels of red blood cell (RBC) thiopurine methyltransferase (TPMT) enzyme activity, renal disease, hepatic dysfunction, or allopurinol within 1 wk of the study date were also excluded. AZA Therapy Hospitalized patients who met entry criteria were pretreated with an open label i.v. loading dose of commercially available AZA (Glaxo-Wellcome, Research Triangle Park, NC). Patients 1–3 received 20 mg/kg as a 36-h infusion; patients 4 – 6 received 40 mg/kg as a 36-h infusion; and patients 7–9 received 40 mg/kg as three 8-h infusions over 3 days. Treatment with commercially available oral AZA (2.0 mg/ kg) was initiated the day after completion of the i.v. AZA loading dose. Dosage adjustment was not performed in response to a lack of efficacy but it was allowed according to a standardized protocol for hepatotoxicity, leukopenia, thrombocytopenia, infection, pancreatitis, malignancy, and other side effects. Hepatotoxicity was defined as an increase in serum AST to a level more than five times the upper limit of normal or an increase in the alkaline phosphatase to a level that was more than three times the upper limit of normal. Leukopenia was defined as a total white blood cell count below 3.0 ⫻ 109/L. Thrombocytopenia was defined as a decrease in the total platelet count below 100 ⫻ 109/L. If hepatotoxicity, leukopenia, or thrombocytopenia occurred, then AZA was discontinued and serum chemistry or a complete blood count was obtained twice weekly until the white blood cell count, platelets, AST, or alkaline phosphatase
Measurements of Clinical Disease Activity Procedures performed at all visits included physical examination, UCDAI, completion of the inflammatory bowel disease questionnaire (IBDQ) regarding quality of life, clinical laboratory assessments, and flexible sigmoidoscopy with endoscopic disease activity assessment. The UCDAI was developed from Truelove and Witts’ criteria for mild, moderate, and severe UC (20) and the criteria from Baron et al. (21) for grading the mucosal appearance. The variables used to calculate the UCDAI were stool frequency and rectal bleeding from the patient’s diary, mucosal appearance from the flexible sigmoidoscopy, as well as a global assessment (physician’s overall impression based on the diary, physical examination, flexible sigmoidoscopy, and laboratory data). This 13-point index (0 –12) has been used previously to assess disease activity in UC by other investigators (22, 23). Toxicity Monitoring Patients were monitored for clinical evidence of AZA toxicity including hepatotoxicity, myelotoxicity, pancreatitis, malignancy, opportunistic infection, and AZA drug fever, rash, arthralgias, and nausea. A complete blood count with differential and liver function tests were obtained at study entry, at completion of infusion of i.v. AZA, and at wk 1, 2, 3, 4, 6, 8, 10, and 12. Blood for measurement of TPMT enzyme activity was obtained before receiving an AZA dose. TPMT activity has a trimodal distribution in the general population (24). Low TPMT activity (⬍5.0 U/ml RBC) occurs in 0.3% of the population; intermediate TPMT activity (5.0 –13.7 U/ml RBC) occurs at a frequency of 11.1%; and high or normal TPMT activity (13.8 –25.1 U/ml RBC) occurs at a frequency of 88.6%. All patients had to have normal TPMT activity (ⱖ13.8 U/ml) to be included in the study. Blood was obtained for measurement of RBC 6-TGN
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Table 1. Baseline Patient Characteristics Characteristics Gender Mean age (yr) Mean weight (kg) Tobacco use Duration of disease (mos) Duration of current exacerbation (mos) Extent of disease Extraintestinal manifestations Mean TPMT (U/ml RBC) Mean UCDAI Mean IBDQ Prior medications (No. of patients)
Data 8 men; 1 woman 44.4 (range, 24–70) 78.6 (range, 53.3–122.1) 7 nonsmokers; 2 former smokers 37.1 (range, 2–108) 2 (range, 1–4) 2 splenic flexure; 7 pancolitis 1 arthritis 18.0 (range, 15.7–22.2) 9 (range, 8–12) 129.4 (range, 95–184) 9 corticosteroids; 9 mesalamine; 2 transdermal nicotine; 1 cyclosporine; 1 metronidazole; 1 ciprofloxacin; 9 corticosteroids; 5 mesalamine; 1 metronidazole; 1 heparin
concentrations before commencing the study, immediately after the last infusion of AZA, and at wk 1, 2, 3, 4, 6, 8, 10, and 12 just before the daily oral AZA dose (25).
RESULTS Nine patients were enrolled in the trial. Patients 1–3 received 20 mg/kg as a 36-h infusion; patients 4 – 6 received 40 mg/kg as a 36-h infusion; and patients 7–9 received 40
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mg/kg as three 8-h infusions over 3 days. Baseline characteristics of the nine patients are outlined in Table 1. Five patients completed the scheduled 12 wk of therapy. Four patients withdrew to undergo colectomy. One patient who achieved remission had received previous therapy with cyclosporine. The remaining eight patients had no previous immunomodulator therapy. Clinical Efficacy Three of the nine patients achieved clinical remission as defined by cessation of steroids and a UCDAI of 0. Two patients achieved a clinical response with withdrawal of steroids and a decrease in the UCDAI to 1 and 3, respectively. All five patients had an IBDQ ⬎170 —a score generally considered to indicate remission (26). For the five patients who did not go to surgery, the improvement in the IBDQ during 12 wk was a mean increase of 67.6 points (range, 32–116). The mean time for the IBDQ to increase ⬎170 was 5 wk (range, 0 – 8). The mean decrease in the UCDAI was 8.2 points (range, 5–11). The UCDAI reached 0 at wk 8 for Patient 8 and at wk 12 for Patients 1 and 9. The decrease in UCDAI scores began by 7 days after infusion in all five patients spared colectomy. Of the three patients who received a 20 mg/kg i.v. AZA loading dose, one attained clinical remission, one had a clinical response with steroid withdrawal and a UCDAI of 1, and one went to surgery within 4 days of receiving the loading dose. The evolution of endoscopic healing in Patient 1 over the 12 wk following the i.v. AZA is shown in Figure 1. Of the three patients who received a 40 mg/kg i.v. AZA
Figure 1. (A) The sigmoid colon of Patient 1 at entry into the trial. Ulcerations and friability are seen throughout. (B) The same patient at wk 4 after infusion of AZA. (C) Wk 8. (D) Wk 12. There is a healed scar seen at the site of previous ulceration.
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Figure 2. Individual patient erythrocyte 6-TGN concentrations after treatment with an i.v. AZA loading dose followed by 2.0 mg/kg/day oral AZA for 12 wk. The RBC 6-TGN concentrations were obtained at baseline, immediately after infusion, and at 1, 2, 3, 4, 8, 10, and 12 wk after infusion.
loading dose, two went to surgery at 12 and 18 days, respectively. The third patient achieved a clinical response with steroid withdrawal and a UCDAI of 3. Three patients received 40 mg/kg i.v. AZA as three 8-h infusions. Of these, two achieved clinical remission and one was referred for surgery at 31 days after infusion. However, this latter patient was not operated on for an additional 2 months due to a deep venous thrombosis. AZA Metabolism The mean baseline TPMT for the nine patients was 18 U/ml RBC. Patients achieved a mean RBC 6-TGN concentration of 120.9 pmol/8 ⫻ 108 RBC (range, 52–206) after the 36-h infusion. The mean RBC 6-TGN concentration at wk 12 was 148.2 (range, 108 –244) for the five patients in clinical remission/response. Patients who received a 20 mg/kg i.v. loading dose had a mean postinfusion RBC 6-TGN concentration of 81.3. Those who received 40 mg/kg had a mean of 126.3. Finally, those who received 40 mg/kg as three 8-h infusions had a mean postinfusion RBC 6-TGN concentration of 155. Figure 2 demonstrates the individual RBC 6-TGN concentrations for each patient over the 12-wk period. Adverse Events Three of the nine patients experienced an adverse event. One patient, who eventually achieved a clinical response, experienced hepatotoxicity 7 days after -infusion and her AZA was immediately discontinued. Her peak liver function tests, which occurred on day 7 after infusion, were an AST 292, ALT 695, and alkaline phosphatase 474. The aminotransferases normalized during 1 wk and she restarted her AZA 11 days after initially discontinuing it. The dose was the same as before the elevation of liver enzymes (125 mg/day or 2.0 mg/kg/day). She had no further problems with hepatotoxicity.
The mean initial WBC concentration was 11.8 ⫻ 109/L. Figure 3 demonstrates the change in the individual WBC concentrations of each patient over the 12-wk period. Two patients experienced leukopenia during the course of the trial. The first patient discontinued his AZA 7 days after infusion when his WBC count dropped to 2.9 ⫻ 109/L. It was restarted the next day when his WBC normalized. Five days later, he had a WBC nadir of 2.3 ⫻ 109/L and the medication was discontinued. The patient received GCSF (Neupogen-Amgen, Thousand Oaks, CA) with a recovery of his WBC count to 3.8 ⫻ 109/L and was taken to surgery the next day. The second patient developed leukopenia 7 days after infusion. His nadir WBC count was 2.7 ⫻ 109/L. His AZA dose was withheld for 5 days and his WBC count increased to 4.1 ⫻ 109/L. AZA was restarted at the same dose of 150 mg/day (2.0 mg/kg/day) and there were no further episodes of leukopenia. He achieved clinical response with steroid withdrawal at 12 wk and a UCDAI of 3.
DISCUSSION Five of nine hospitalized patients (56%) with severe steroid refractory UC administered an i.v. loading dose of AZA avoided colectomy. All five had complete steroid withdrawal by wk 12. Three (33%) met the definition of clinical remission at 12 wk, with steroid withdrawal and a UCDAI of 0. The two patients who did not undergo colectomy, yet did not attain full clinical remission had a reduction of their AZA dose secondary to toxicity. It is conceivable that their 12-wk UCDAI would have reached 0 if they had tolerated continuous full-dose therapy. A randomized trial by Sandborn et al. (19) in 1999 demonstrated that i.v. AZA does not decrease the time to response or increase the response rate over oral AZA alone in the setting of Crohn’s disease. This study also suggested
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Figure 3. Individual patient WBC concentrations after treatment with i.v. AZA loading dose followed by 2.0 mg/kg/day oral AZA for 12 wk. The WBC concentrations were obtained at baseline, immediately after infusion, and at 1, 2, 3, 4, 8, 10, and 12 wk after infusion. Overall, there was a decrease in the WBC concentrations over the 12 wk, but there was no difference between the responders and nonresponders with respect to leukopenia.
that AZA works more rapidly than previously believed (16, 17). In our study, patients demonstrated decreasing UCDAI scores and increasing IBDQ scores by wk 2. By wk 4, the mean IBDQ had increased from a baseline mean of 129.4 – 174.5, above the 170-point minimum used to define clinical remission. The mean UCDAI at wk 4 had decreased from a mean of 9 –3.4 points; by wk 5 the mean was 1.8 points. This is consistent with the Crohn’s i.v. AZA trial, suggesting that AZA (oral or i.v.) demonstrates a significant effect by 2– 4 wk in UC as well as in Crohn’s disease. Although this is a small open-label trial, the 56% colectomy-sparing rate in patients who have failed i.v. corticosteroids is impressive. This suggests that AZA could have a role in the acute setting of severe UC. By extrapolation from the Crohn’s i.v. AZA trial, oral therapy with AZA alone may be adequate to achieve an early response in 2– 4 wk. A study by Casson et al. (27) suggested that a low dose of i.v. AZA was beneficial in fulminant colitis. Three patients received i.v. AZA for 5–7 days. Both a sustained response and a steroid reduction were achieved. Clinical response was associated with mucosal healing. They suggested that the rapid response might reflect immunological differences between chronic severe disease and the acute changes of toxic dilatation. The i.v. doses of AZA were 2.3–2.6 mg/kg/day, which is equivalent to the standard oral dosing of 5.0 mg/ kg/day. Steady-state concentrations of RBC 6-TGN were reached at the end of 1 wk in the nine patients studied. Erythrocyte 6-TGN levels have been shown to have an inverse correlation with the Harvey-Bradshaw Index in patients with Crohn’s disease (28). A study by Dubinsky et al. (29) found that 65% of patients who had induction of remission of Crohn’s disease while on 6-MP had a 6-TGN concentration
⬎230 pmol/8 ⫻ 108 RBC. We used a different assay for RBC 6-TGN (25) than that used by Cuffari and Dubinsky. A conversion factor of 1.6 can be used to convert the RBC 6-TGN concentration determined by our assay methodology to equivalent values for the assay used by Prometheus Laboratories (San Diego, CA) and by Cuffari and Dubinsky. The correlation coefficient between the two assays is 99%. (WJ Sandborn, unpublished data). Of the five patients in our study who responded, the mean RBC 6-TGN concentration was 148.2 pmol/8 ⫻ 108 RBC (range, 108 –244). This would be equivalent to a mean concentration of 237.1 pmol/ 8 ⫻ 108 using the Prometheus Laboratories assay system. Two of the three patients who met the definition of remission had the equivalent of ⬎230 pmol/8 ⫻ 108 RBCs, although both patients who responded but did not have complete remission had a concentration ⬍230. The clinical utility of measuring metabolite levels of AZA warrants further study. The mean WBC count decreased from 11.8 ⫻ 109/L to 6.3 ⫻ 109/L. As in the i.v. AZA Crohn’s trial, remission was not associated with leukopenia. TPMT activity was in the homozygous or normal range in all patients. Although no serious adverse events occurred, two patients did have transient leukopenia and one had transient hepatotoxicity. These adverse events resolved quickly and the two patients who did not require surgery for lack of response were able to restart AZA at the same dosage without further toxicity. Patients with heterozygous or homozygous low TPMT activity were not included in the trial. The safety of i.v. AZA in these patients is not known. In conclusion, i.v. AZA is safe and appears to be of benefit in inducing remission and avoiding colectomy in patients with severe steroid refractory UC. Extrapolation
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from the i.v. AZA Crohn’s trial suggests that oral dosing at 2 mg/kg/day could have an equivalent result. The actual avoidance of colectomy in 56% of patients who failed i.v. steroids suggests a possible role for AZA, oral or i.v., in the acute setting. It appears that AZA is safer than cyclosporine and can be used for long-term maintenance of remission. Further studies are needed to determine the efficacy of oral or low dose i.v. AZA in severe UC, as well as for the role of TPMT and the metabolite 6-TGN in determining safety and optimizing response.
ACKNOWLEDGMENTS This study was funded in part by the Mayo Foundation for Research and Education. Intravenous and oral azathioprine was provided by Glaxo Wellcome (Research Triangle Park, NC). Reprint requests and correspondence: William J. Sandborn, M.D., Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905. Received Mar. 21, 2000; accepted July 24, 2000.
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