Intravenous azathioprine in severe ulcerative colitis: a pilot study

Systematic Literature Review: Ability of the IBDQ-32 to Detect Meaningful Change in Ulcerative Colitis Health Indicators

PURPOSE

Previous reviews produced weak evidence regarding the responsiveness of the Inflammatory Bowel Disease Questionnaire (IBDQ-32) to changes in ulcerative colitis (UC) health indicators. This systematic review and meta-analysis provide an updated synthesis on IBDQ-32 responsiveness.

METHODS

A systematic literature review identified 11 articles reporting IBDQ-32 responder analyses in randomized control trials, which were included in a random effects meta-analysis, and 15 articles linking IBDQ-32 change to change in UC health indicators, which were summarized narratively. Meta-analysis compared differences between IBDQ-32 responder proportions in efficacious and nonefficacious treatment arms relative to placebo. Linear meta-regression examined the association of treatment efficacy and proportions of IBDQ-32 responders in active treatment compared with placebo.

RESULTS

Meta-analysis showed larger differences in IBDQ-32 response proportions between active treatment and placebo for efficacious treatments (pooled OR, 2.19; 95% CI, 1.83-2.63) than nonefficacious treatments (pooled OR, 1.21; 95% CI, 0.84-1.74; Cochran's Q[df = 1] = 8.26, P = .004). Meta-regression showed that the magnitude of treatment efficacy positively predicted IBDQ-32 response in active treatments relative to placebo (β = 0.21, P < .001). Moderate to strong correlations were found between change in IBDQ-32 and change in health indicators (eg, patient-reported measures, disease activity, endoscopic indices; correlations, 0.37-0.64 in absolute values). Patients achieving clinical response or remission showed greater change in IBDQ-32 total scores (range, 22.3-50.1 points) and more frequently met clinically meaningful thresholds on the IBDQ-32 than those not achieving clinical response or remission (all P < .05).

CONCLUSIONS

The IBDQ-32 is responsive to changes in UC health indicators and disease activity, including in response to efficacious treatment (relative to placebo).

Direct comparison of two different mesalamine formulations for the maintenance of remission in patients with ulcerative colitis: a double-blind, randomized study

BACKGROUND

Mesalamine has been used as the first-line medication for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two different mesalamine formulations in the maintenance of remission in patients with UC.

METHODS

In a multicenter, double-blind, randomized study, 131 patients with quiescent UC were assigned to two groups: 65 to receive a pH-dependent release formulation of mesalamine at 2.4 g/day (pH-2.4 g) and 66 to receive a time-dependent release formulation of mesalamine at 2.25 g/day (Time-2.25 g). Both formulations were administered three times daily for 48 weeks. The primary endpoint was the proportion of patients without bloody stools.

RESULTS

In the full analysis set (n = 130), the proportion of patients without bloody stools was 76.9% in the pH-2.4 g and 69.2% in the Time-2.25 g, demonstrating the noninferiority of pH-2.4 g to Time-2.25 g. No statistically significant difference in time to bloody stools was found between the two formulations (P = 0.27, log-rank test), but the time to bloody stools tended to be longer in pH-2.4 g compared to Time-2.25 g, and a similar trend was observed with regard to the time to relapse. No differences were observed between the safety profiles of the two formulations.

CONCLUSIONS

The pH- and time-dependent release of mesalamine formulations were similarly safe and effective. Interestingly, the remission phase tended to be longer in the group that received the pH-dependent formulation compared to the group that received the time-dependent formulation (UMIN Clinical Trials Registry, no. C000000289).

Quantitative in vitro and in vivo characterization of the human P32T mutant ITPase

Human ITPase, encoded by the ITPA gene, and its orthologs (RdgB in Escherichia coli and HAM1 in Saccharomyces cerevisiae) exclude noncanonical nucleoside triphosphates (NTPs) from NTP pools. Deoxyinosine triphosphate (dITP) and 2'-deoxy-N-6-hydroxylaminopurine triphosphate are both hydrolyzed by ITPase to yield the corresponding deoxynucleoside monophosphate and pyrophosphate. In addition, metabolites of thiopurine drugs such as azathioprine have been shown to be substrates for ITPase. The ITPA 94C>A [P32T] variant is one of two polymorphisms associated with decreased ITPase activity. Furthermore, the ITPA 94C>A [P32T] variant is associated with an increased risk of adverse drug reactions for patients treated with azathioprine. The nature of the observed phenotypes for ITPA 94C>A [P32T] variant individuals is currently unclear. Our biochemical assays indicate the P32T ITPase has 55% activity with dITP compared to wild-type ITPase. Complementation experiments at 37 degrees C show that N-6-hydroxylaminopurine sensitivity of E. coli rdgB mutants is reduced with a plasmid bearing the ITPA 94C>A [P32T] gene approximately 50% less than with a plasmid bearing the wild-type ITPA gene. The reduction in sensitivity is less at 42 degrees C. Experiments with synthetic lethal E. coli recA(ts) rdgB mutants show that the ITPA 94C>A [P32T] gene also complements the recA(ts) rdgB growth deficiency at 42 degrees C approximately 40% lower than wild-type ITPA gene. Western blot analysis indicates that the expression level of P32T ITPase is reduced in these cells relative to wild type. Our data support the idea that P32T ITPase is a functional protein, albeit with a reduced rate of noncanonical NTP pyrophosphohydrolase activity and reduced protein stability.

Meta-analysis: the efficacy of azathioprine and mercaptopurine in ulcerative colitis

BACKGROUND

Debate exists regarding to whether thiopurine therapy is as effective in ulcerative colitis (UC) as it is in Crohn's disease.

AIM

To review systematically the efficacy of azathioprine (AZA) and mercaptopurine (MP) in UC, and to conduct a meta-analysis of randomized clinical trials evaluating the efficacy of AZA/MP for the induction or maintenance of UC clinical remission.

SELECTION OF STUDIES

Evaluating AZA/MP for induction and/or maintenance of clinical remission of UC. Randomized-controlled-trials comparing AZA/MP with placebo/5-aminosalicylates were included in the meta-analysis.

SEARCH STRATEGY

Electronic and manual. Study quality: Independently assessed by two reviewers.

DATA SYNTHESIS

By 'intention-to-treat'.

RESULTS

Thirty noncontrolled studies (1632 patients) were included in the systematic review. Mean efficacy of AZA/MP was 65% for induction and 76% for maintenance of the remission. Seven controlled studies were included in the meta-analysis. (i) Induction of remission: four studies (89 AZA/MP-treated patients) showed mean efficacy of 73% vs. 64% in controls (OR = 1.59; 95% CI = 0.59-4.29). (ii) Maintenance of remission: six studies (124 AZA/MP-treated patients) showed mean efficacy of 60% vs. 37% in controls (OR = 2.56; 95% CI = 1.51-4.34). When only studies comparing AZA/MP vs. placebo were considered, OR was 2.59 (95% CI = 1.26-5.3), absolute risk reduction was 23% and number-needed-to-treat (NNT) to prevent one recurrence was 5.

CONCLUSION

Thiopurine drugs (AZA/MP) are more effective than placebo for the prevention of relapse in UC, with an NNT of 5 and an absolute risk reduction of 23%.

US estimates of hospitalized pediatric patients with ulcerative colitis: implications for multicenter clinical studies

BACKGROUND

The optimal clinical management of children hospitalized with ulcerative colitis (UC) is evolving. There are limited data quantifying the number of pediatric patients with UC admitted to hospitals in the United States. We analyzed the Kids' Inpatient Database (KID, 2003), to estimate the distribution of hospitalized children with UC and estimate sample sizes available for clinical research.

METHODS

We limited our analysis to subjects age less than 18 years. We defined cases of UC as discharge records associated with an ICD-9 code of 556.0-556.9 in the first position. We defined colectomy as principal procedure code of 45.8. We generated weighted estimates for these analyses. To estimate the relationship between number of patients and number of hospitals necessary for clinical trials, we generated 1000 simulated datasets.

RESULTS

A total of 2311 UC cases were identified. The mean age at admission was 13.1 (standard error [SE] 0.1) years, and 9% (SE 0.9%) underwent colectomy during their hospitalization. 1008 UC cases were treated at high-volume hospitals; the majority of these children were treated at children's hospitals. Simulation studies suggest that approximately 5 high-volume hospitals would be necessary to generate sample sizes necessary for a pilot clinical trial of refractory UC.

CONCLUSIONS

Approximately half of all young patients hospitalized with UC in the US were treated at a limited number of high-volume hospitals, and approximately 5 such centers would be adequate for pilot clinical trials of hospitalized patients with refractory UC.

Clinical pharmacology and pharmacogenetics of thiopurines

The thiopurine drugs-azathioprine (AZA), 6-mercaptopurine (6-MP), and thioguanine-are widely used to treat malignancies, rheumatic diseases, dermatologic conditions, inflammatory bowel disease, and solid organ transplant rejection. However, thiopurine drugs have a relatively narrow therapeutic index and are capable of causing life-threatening toxicity, most often myelosuppression. Thiopurine S-methyltransferase (TPMT; EC 2.1.1.67), an enzyme that catalyzes S-methylation of these drugs, exhibits a genetic polymorphism in 10% of Caucasians, with 1/300 individuals having complete deficiency. Patients with intermediate or deficient TPMT activity are at risk for excessive toxicity after receiving standard doses of thiopurine medications. This report reviews the recent advances in the knowledge of the mechanism of action as well as the molecular basis and interethnic variations of TPMT and inosine triphosphate pyrophosphatase (ITPase; EC 3.6.1.19), another enzyme implicated in thiopurine toxicity. In addition, an update on pharmacokinetics, metabolism, drug-drug interactions, safety, and tolerability of thiopurine drugs is provided.

Bowman-Birk inhibitor concentrate: a novel therapeutic agent for patients with active ulcerative colitis

Bowman-Birk inhibitor concentrate (BBIC), a soy extract with high protease inhibitor activity, is efficacious in the treatment of colitis in mice and has been used in numerous clinical trials. A randomized, double blind, placebo-controlled trial was performed to investigate the safety and possible benefits of BBIC in patients with active ulcerative colitis. The Sutherland Disease Activity Index (SDAI) was used to assess disease activity, response (Index decrease > or = 3), and remission (Index < or = 1 with no rectal bleeding) in patients receiving 12 weeks of therapy. The Index scores of patients receiving BBIC decreased more than those of the patients receiving placebo (P = 0.067). Beneficial trends were observed in the rates of remission (P = 0.082) and clinical response (P = 0.22). No severe adverse events were observed. This trial suggests a potential benefit over placebo for both achieving clinical response and induction of remission in patients with active ulcerative colitis without apparent toxicity.

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

BACKGROUND

The long-term effectiveness of azathioprine, in Crohn's disease (CD) patients remains a matter of debate. This study aims at assessing the effectiveness and safety of azathioprine in patients treated continuously for less or more than 4 years.

METHODS

Patients with steroid-dependent Crohn's disease in remission on azathioprine (2-2.5 mg/kg) for between 2 and 8 years were assigned into two groups. Patients in Group A were being treated continuously for 2 to 4 years whereas patients in Group B for 4 to 8 years. Patients were followed every month for 1 year with physical examination and laboratory tests. Compliance with treatment was also assessed every month. Every 3 months the Crohn's Disease Activity Index (CDAI) was calculated and the quality of life (QOL) Inflammatory Bowel Disease Questionnaire (IBDQ) was completed. Colonoscopy with calculation of the Crohn's Disease Endoscopic Index of Severity (CDEIS) was performed at baseline and at the end of the study. The primary end point was relapse after 1 year. Secondary end points were safety of treatment, QOL, and endoscopic healing.

RESULTS

Fifty-eight patients were included in Group A and 42 in Group B. The relapse rates per protocol were 19.6% and 11.9%, respectively (p: not significant). There were no significant differences overall and at each time point of the study between the two treatment groups regarding compliance with and safety of treatment, CDAI, IBDQ, and CDEIS scores. Multifactorial analysis did not identify any factor influencing the remission of disease in any patient group.

CONCLUSIONS

Long-term treatment with azathioprine of steroid-dependent Crohn's disease is efficacious and safe.

Thiopurine treatment in inflammatory bowel disease: clinical pharmacology and implication of pharmacogenetically guided dosing

This review summarises clinical pharmacological aspects of thiopurines in the treatment of chronic inflammatory bowel disease (IBD). Current knowledge of pharmacogenetically guided dosing is discussed for individualisation of thiopurine therapy, particularly to avoid severe adverse effects. Both azathioprine and mercaptopurine are pro-drugs that undergo extensive metabolism. The catabolic enzyme thiopurine S-methyltransferase (TPMT) is polymorphically expressed, and currently 23 genetic variants have been described. On the basis of an excellent phenotype-genotype correlation for TPMT, genotyping has become a safe and reliable tool for determination of a patient's individual phenotype. Thiopurine-related adverse drug reactions are frequent, ranging from 5% up to 40%, in both a dose-dependent and -independent manner. IBD patients with low TPMT activity are at high risk of developing severe haematotoxicity if pharmacogenetically guided dosing is not performed. Based on several cost-benefit analyses, assessment of TPMT activity is recommended prior to thiopurine therapy in patients with IBD. The underlying mechanisms of azathioprine/mercaptopurine-related hepatotoxicity, pancreatitis and azathioprine intolerance are still unknown. Although the therapeutic response appears to be related to 6-thioguanine nucleotide (6-TGN) concentrations above a threshold of 230-260 pmol per 8 x 10(8) red blood cells, at present therapeutic drug monitoring of 6-TGN can be recommended only to estimate patients' compliance.Drug-drug interactions between azathioprine/mercaptopurine and aminosalicylates, diuretics, NSAIDs, warfarin and infliximab are discussed. The concomitant use of allopurinol without dosage adjustment of azathioprine/mercaptopurine leads to clinically relevant severe haematotoxicity due to elevated thiopurine levels. Several studies indicate that thiopurine therapy in IBD during pregnancy is safe. Thus, azathioprine/mercaptopurine should not be withdrawn in strictly indicated cases of pregnant IBD patients. However, breastfeeding is contraindicated during azathioprine/mercaptopurine therapy. Use of azathioprine/mercaptopurine for induction and maintenance of remission in corticosteroid-dependent or corticosteroid-refractory IBD, particularly Crohn's disease, is evidence based. To improve response rates in thiopurine therapy of IBD, comprehensive analyses including metabolic patterns and genome-wide profiling in patients with azathioprine/mercaptopurine treatment are required to identify novel candidate genes.

Medical management of left-sided ulcerative colitis and ulcerative proctitis: critical evaluation of therapeutic trials

BACKGROUND

The goal of this work was to critically evaluate the published studies on the treatment of ulcerative proctitis (UP) and left-sided ulcerative colitis (L-UC). The results of this review provided the content for the accompanying treatment guidelines, Clinical Guidelines for the Medical Management of Left-sided Ulcerative Colitis and Ulcerative Proctitis: Summary Statement.

METHODS

All English language articles published between 1995 and September 2005 were identified through a comprehensive literature search using OVID and PubMed. The quality of the data supporting or rejecting the use of specific therapies was categorized by a data quality grading scale. An "A+" grade was assigned to treatment supported by multiple high-quality randomized controlled trials with consistent results, whereas a "D" grade was given to therapy supported only by expert opinion. The therapeutic efficacy of a treatment was defined by its success in treating UP and L-UC compared with placebo. A medication was ranked as "excellent" if it was specifically studied for UP and L-UC and had consistently positive results compared with placebo or another agent. Quality and efficacy scores were agreed on by author consensus.

RESULTS

For the acute treatment of UP or L-UC, the rectally administered corticosteroids and mesalazine (5-ASA), either alone or in combination with oral 5-ASAs, are the most effective therapy: evidence quality, A+; efficacy, excellent. Only rectally administered 5-ASA received an A+/excellent rating for maintenance of remission. Infliximab received an A+ grade for induction and maintenance of remission but only a "good" rating because the studies were performed in all UC, not specifically UP or L-UC.

CONCLUSIONS

This critical evaluation of treatment provides a "report card" on medications available for the management of patients with UP and L-UC. The guidelines should provide a useful reference and supplement for physicians treating UC patients.

High-dose azathioprine pulse therapy as a new treatment option in patients with active Wegener's granulomatosis and lupus nephritis refractory or intolerant to cyclophosphamide

The objective of this study was to evaluate the feasibility and safety of high-dose azathioprine pulse (HAP) therapy in the induction of remission in patients with active Wegener's granulomatosis (WG) or progressive lupus nephritis (LN) refractory to or intolerant of cyclophosphamide. Four patients with antineutrophil cytoplasmic antibody (ANCA)-associated WG and two patients with progressive LN were treated with HAP (1200-1800 mg) applied monthly as continuous intravenous infusions at 50 mg/h. Patients received a total of 50 courses of intravenous azathioprine (AZA) therapy. Disease activity was assessed using the Birmingham Vasculitis Activity Score (BVAS) and the Systemic Lupus Erythematosus Activity Index (SLEDAI). As only partial remission was induced in patients with progressive LN on this regimen, an additional 18 cycles were applied in these patients in which oral AZA at 100 mg/day in weeks 2 and 3 was added between two intravenous courses. A hereditary defect in thiopurine methyltransferase activity was excluded before initiation of treatment. High-dose azathioprine pulse and the intensified HAP treatment were well tolerated. Complete remission was achieved in two patients with WG suffering from three relapses of disease on application of 2-6 courses of HAP. Remission was maintained for 16-24 months. The remaining two patients with WG were withdrawn after 2-3 courses due to unchanged disease activity. In two patients with LN, partial remission was noted on 6-9 courses of HAP; however, the patients relapsed despite therapy with methotrexate and mycophenolate mofetil. The intensified HAP regimen led to partial or complete remission in both LN patients which was confirmed by sequential renal biopsies. Our results suggest that HAP therapy represents a well-tolerated regimen in patients with active WG and LN intolerant of or refractory to cyclophosphamide. As partial or complete remission was observed in four of six patients, further studies seem warranted to assess clinical efficacy in these patients.

Improved HPLC methodology for monitoring thiopurine metabolites in patients on thiopurine therapy

OBJECTIVE

Standardization of thiopurine metabolite testing is currently lacking. This paper presents in-depth methodological analysis and optimization of two currently available HPLC procedures (Lennard-Singleton [J. Chromatogr. 583 (1992) 83] and Dervieux-Boulieu [Clin. Chem. 44 (1998) 551]) to improve precision, turn-around time, ruggedness, and cost effectiveness.

DESIGN AND METHODS

Reversed-phase chromatography with UV detection was performed on a Waters HPLC system. The two protocols were improved with regards to internal standardization (IS), chromatographic conditions, as well as reagent preparation, storage, and use. 6-Thioguanine nucleotides (6-TGNs) were analyzed by our optimized techniques in samples from patients on thiopurine therapy (n = 24) and the results were compared.

RESULTS

6-Mercaptopurine (6-MP) was an ideal internal standard in either procedure. Isocratic elution with 5% acetonitrile (ACN) in 20 mmol/l phosphate buffer pH 2.5 allowed for minimal background interference in both protocols. 6-Thioguanine, 6-mercaptopurine, and 6-methylmercaptopurine (6-MMP) eluted at around 4, 5, and 6 min, respectively. Dithiothreitol (DTT) was critical only during the acid hydrolysis step. Less mercury-containing waste was generated in the Lennard-Singleton procedure. With our optimized protocols recovery of 6-TGNs was on average 1.38-fold higher in the Dervieux-Boulieu method over a range of 10-678 pmol/8 x 10(8) RBC and no interfering peaks hindered analysis. Specific extraction of thiopurines before their analysis as per Lennard-Singleton procedure may be redundant.

CONCLUSIONS

We improved the quality and cost effectiveness of two known procedures for thiopurine metabolite assay. Through common chromatographic conditions and internal standardization, future comparison studies are now facilitated a great deal. The less tedious Dervieux-Boulieu procedure for routine thiopurine metabolite testing is warranted.

Treatment of inflammatory bowel disease with azathioprine and 6-mercaptopurine

6-Mercaptopurine and azathioprine have become important therapeutic options for patients with inflammatory bowel disease (IBD). Although accumulating data in the literature have supported the use of these immunomodulators in the management of IBD, marked variation exists in the pattern of clinical practice regarding azathioprine or 6-mercaptopurine therapy in patients with IBD. This article provides a critical review of the data on the clinical efficacy and toxicities of 6-mercaptopurine and azathioprine in the management of IBD. Emerging literature on the potential application of pharmacogenetic testing and metabolite monitoring are also discussed.

Treatment of inflammatory bowel disease with azathioprine and 6-mercaptopurine

6-Mercaptopurine and azathioprine have become important therapeutic options for patients with inflammatory bowel disease (IBD). Although accumulating data in the literature have supported the use of these immunomodulators in the management of IBD, marked variation exists in the pattern of clinical practice regarding azathioprine or 6-mercaptopurine therapy in patients with IBD. This article provides a critical review of the data on the clinical efficacy and toxicities of 6-mercaptopurine and azathioprine in the management of IBD. Emerging literature on the potential application of pharmacogenetic testing and metabolite monitoring are also discussed.

A prospective randomized observer-blind 2-year trial of azathioprine monotherapy versus azathioprine and olsalazine for the maintenance of remission of steroid-dependent ulcerative colitis

OBJECTIVE

The aim of this prospective study was to assess whether the coadministration of azathioprine (AZA) and olsalazine is superior to AZA monotherapy in maintaining remission of steroid-dependent ulcerative colitis (UC).

METHODS

Patients with steroid-dependent UC in remission were randomized to receive AZA alone (2.2 mg/kg) or in combination with olsalazine (0.5 g tid). Remission was defined as steroid withdrawal, an Ulcerative Colitis Clinical Activity Index (UCCAI) score of <2, an Ulcerative Colitis Disease Activity Index (UCDAI) score of 0, and a negative colonoscopy and histology. Patients were followed in the outpatient clinic every month for 2 yr. The study protocol included 1) monthly clinical examination, assessment of UCCAI, hematological and biochemical tests, and compliance with treatment; 2) a sigmoidoscopy and completion of inflammatory bowel disease quality-of-life questionnaire (IBD-Q) and UCDAI every 3 months; and 3) total colonoscopy with biopsies at the end of the first and second year of the trial.

RESULTS

Seventy patients were randomized to receive AZA alone (n = 34) or with olsalazine (n = 36). Three patients in each group developed side effects or could not comply with treatment and were withdrawn from the study. Three patients receiving AZA relapsed after the first year of the study and three after the second year of the study (19%). In the combination therapy group four patients relapsed after the first year of study and two after the second year of the study (18%). Relapse rates were not significant whether analyzed by intention-to-treat or per protocol. There were no significant differences between groups in time to relapse or discontinuation of treatment, UCCAI, UCDAI, or IBD-Q scores. However, the number of adverse events and the cost of treatment were significantly higher, whereas compliance with treatment was poorer in the combination therapy.

CONCLUSION

Patients with steroid-dependent UC successfully maintained in remission on AZA are not in need of 5-aminosalicylic acid compounds.

Medical management of severe ulcerative colitis

The medical management of patients with severe ulcerative colitis requires initial stabilization, careful and repeated evaluations to exclude confounding or coexisting diagnoses, and timely delivery of appropriate medications. Medical therapies for these patients are potent but may be toxic, and administration must be done by experienced medical professionals, with adequate access to appropriate laboratory, radiographic, endoscopic, and surgical facilities. Patients who fail to respond to high-dose intravenous corticosteroids in a timely basis should be evaluated for cyclosporin therapy, or proceed to surgery. The promise of newer, investigational therapies to induce and maintain remission must be borne out by large controlled trials.

Medical treatment of ulcerative colitis

Ulcerative colitis is a chronic inflammatory disease of the colon with an increasing incidence worldwide. The medical management of this disease continues to expand as drugs to induce and maintain remission are sought to avoid the need for colectomy. This article will review the standard of care for the treatment of mild, moderate, and severe ulcerative colitis. The efficacy, optimal usage, and adverse events profile of agents such as 5-aminosalicylates, corticosteroids, azathioprine, and cyclosporine will be discussed and an algorithm for their use will be developed. Alternative and experimental therapies such as monoclonal antibodies, probiotics, and heparin will also be addressed.

Optimizing treatment with thioguanine derivatives in inflammatory bowel disease

Thioguanine derivatives, azathioprine and 6-mercaptopurine, represent major drugs in the treatment of chronic active inflammatory bowel disease. They are effective in two-thirds of the patients and safe over the long term in patients who can tolerate them (80-90%). Recent progress in understanding the metabolism of these drugs and its implication in clinical practice have brought up new tools and strategies that are proposed to optimize treatment. In particular, the measurement and characterization of key enzymes and metabolites may have clinical impact. Thus, thiopurine methyl transferase genotyping and activity measurement, as well as erythrocytes, 6-thioguanine nucleotides and 6-methyl mercaptopurine levels, may help in some situations of intolerance or inefficacy with these drugs. Indications for starting and stopping treatment with thioguanine derivatives are also discussed.

Evolving medical therapies for ulcerative colitis

Therapies for patients with ulcerative colitis have, until recently, been limited in scope and efficacy. New formulations of mesalamine and corticosteroids have challenged the older therapies with respect to both efficacy and safety. The application of 6-mercaptopurine and azathioprine for steroid-refractory disease and maintenance of remission has resulted in studies of other candidate immunomodulatory agents. Biologic therapies targeting tumor necrosis factor, adhesion molecules, or other cytokines are under intense scrutiny as potential disease-altering agents that may even replace currently available products. Other approaches, including such wide-ranging products as heparin, nicotine, and probiotics, suggest that control of ulcerative colitis may require an individualized approach for each patient.

Update in medical therapy of ulcerative colitis: a practical approach

The bewildering array of medications in the therapy of inflammatory bowel disease (IBD) often confounds the clinician in the choice of specific agents regarding the balance between safety and efficacy. This review surveys and evaluates currently available IBD therapies as well as those used in clinical trials of ulcerative colitis. The primary purpose is to provide the busy clinician with a practical guide to the use of established and newly emerging medical therapies of IBD.

Inflammatory bowel disease. Medical therapy of specific clinical presentations

Ulcerative colitis and Crohn's disease are chronic relapsing inflammatory disorders of the gastrointestinal tracts. The inflammatory process is restricted to the mucosa and submucosa of the colon in ulcerative colitis and is transmural and may occur anywhere in the gastrointestinal tract in Crohn's disease. Clinical presentation of these inflammatory disorders depends on the segments of digestive tract affected and on the extent and aggressiveness of the disease process. The treatment of specific clinical presentations of these disorders is discussed in this article.

Evolving medical therapies for ulcerative colitis

Patients with ulcerative colitis have traditionally relied on sulfasalazine, mesalamine, and corticosteroids as the mainstay of medical therapy. Steroid-refractory, -dependent, or -intolerant patients have resorted to agents such as cyclosporine for short-term efficacy and 6-mercaptopurine or azathioprine for long-term efficacy. The next generation of evolving therapies includes many novel agents that target various aspects of the human immune response. Therapies that block the production or action of tumor necrosis factor have received much interest in inflammatory bowel disease. Treatments currently under study include interleukins, interferons, T-cell selective antibodies, molecules involved in cellular trafficking and signaling, mucosal healing or growth factors, and novel steroid agents. Other "less traditional" therapies, including probiotics, heparins, and anti-gastric ulcer remedies, challenge our understanding of the pathogenesis of ulcerative colitis and may provide further insights into future therapies.

Immunomodulator Therapy in Inflammatory Bowel Disease

6-Mercaptopurine and its prodrug counterpart, azathioprine, have proven efficacy in the induction and maintenance of remission, fistula closure, and steroid sparing in patients with Crohn's disease. Long-term follow-up has demonstrated the safety of the purine analogues, with no increased risk of malignancy. For patients with Crohn's disease intolerant or unresponsive to azathioprine or 6-mercaptopurine, methotrexate has emerged as an effective alternative. In patients with severe ulcerative colitis, intravenous cyclosporine is highly efficacious in the short term, and with the addition of azathioprine or 6-mercaptopurine to oral cyclosporine, long-term remission rates of 60% to 70% can be achieved. Azathioprine or 6-mercaptopurine therapy is effective in patients with steroid-dependent or steroid-refractory colitis and is valuable in maintaining remission. Neither methotrexate nor cyclosporine has been shown to be effective for maintenance therapy in patients with ulcerative colitis. Current data are insufficient to recommend routine use of genetic or enzymatic testing of thiopurine methyltransferase or measurements of blood 6-thioguanine metabolites to guide 6-mercaptopurine or azathioprine dosing.