Clinical pharmacology of 5-ASA compounds in inflammatory bowel disease

Advances in molecular mechanisms of inflammatory bowel disease‑associated colorectal cancer (Review)

The link between inflammation and cancer is well documented and colonic inflammation caused by inflammatory bowel disease (IBD) is thought to be a high-risk factor for the development of colorectal cancer (CRC). The complex crosstalk between epithelial and inflammatory cells is thought to underlie the progression from inflammation to cancer. The present review collates and summarises recent advances in the understanding of the pathogenesis of IBD-associated CRC (IBD-CRC), including the oncogenic mechanisms of the main inflammatory signalling pathways and genetic alterations induced by oxidative stress during colonic inflammation, and discusses the crosstalk between the tumour microenvironment, intestinal flora and host immune factors during inflammatory oncogenesis in colitis-associated CRC. In addition, the therapeutic implications of anti-inflammatory therapy for IBD-CRC were discussed, intending to provide new insight into improve clinical practice.

MMX mesalamine in ulcerative colitis: Major advantages towards classical mesalamine formulations

Medical therapy is the cornerstone of ulcerative colitis (UC) management and aims to induce and maintain remission. In case of mild-to-moderate UC, mesalamine (5-ASA) is the first-line option. 5-ASA requires local release at the level of the inflamed mucosa to exert its therapeutic action. While rectal preparations are useful in distal colitis, in cases of UC of at least rectosigmoid extent, guidelines suggest the association of oral and rectal 5-ASA. Mesalamine with Multi Matrix System® technology (MMX mesalamine) is an oral, high-strength (1.2 g/tablet), once-daily formulation of 5-ASA, designed to provide delayed and prolonged release throughout the entire colon. Clinical trials demonstrated a strong efficacy in inducing and maintaining clinical and endoscopic remission in active mild-to-moderate UC. The efficacy is related to specific colonic drug-delivery, to its high-dosage and once-daily administration, thus improving patients' adherence and outcomes. The specific colonic-delivery is also associated with very low rates of systemic absorption and adverse events (AEs). With this comprehensive review we aimed to summarize current knowledge on MMX mesalamine in mild-to-moderate UC, in terms of clinical pharmacology, efficacy and safety, also compared to other 5-ASA products. In addition we provided an expert opinion on the topic, examining the implications on clinical practice.

Molecular Mechanisms of the Antitumor Effects of Mesalazine and Its Preventive Potential in Colorectal Cancer

Chemoprevention is one of the ways to fight colorectal cancer, which is a huge challenge in oncology. Numerous pieces of evidence indicate that chronic inflammation in the course of Crohn's disease or ulcerative colitis (UC) is a significant cancer risk factor. Epidemiologic studies suggest that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs), including mesalazine, has beneficial effects on colitis-associated colorectal cancer. Mesalazine is a first-line therapy for UC and is also widely used for maintaining remission in UC. Data showed that mesalazine has antiproliferative properties associated with cyclooxygenase (COX) inhibition but can also act through COX-independent pathways. This review summarizes knowledge about mesalazine's molecular mechanisms of action and chemopreventive effect by which it could interfere with colorectal cancer cell proliferation and survival.

The Protective Effect of Heat-Inactivated Companilactobacillus crustorum on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Heat-inactivated microorganisms are a typical class of postbiotics with promising potential health effects, as they contain various physiologically active components. Dietary supplementation with Companilactobacillus crustorum MN047 (CC) has been shown to have the potential to alleviate ulcerative colitis (UC). However, it is unclear whether the UC-relieving effect of this strain is partly attributed to its bacterial composition. Therefore, the interventional effects of heat-inactivated CC (HICC) on UC mice were explored. The results showed that the administration of HICC significantly ameliorated the UC-related pathological parameters by (1) alleviating the pathologic lesions of UC (e.g., preventing the increase in disease activity index and the shortening of colon length); (2) ameliorating the colonic inflammation (e.g., inhibiting the expressions of chemokines and pro-inflammatory cytokines, such as Cxcl1, Cxcl5, Ccl7, TNF-α, IL-1β, IL-6, and MCP-1; (3) attenuating the oxidative damage (e.g., suppressing the increase in myeloperoxidase and malondialdehyde); (4) mitigating the damage of gut barrier (e.g., promoting colonic occludin, ZO-1, and claudin levels); and (5) modulating gut microbiota structure (e.g., increasing the relative abundance of potential probiotics, such as Akkermansia and Lactobacillus). In conclusion, our study suggested that HICC can be effective in preventing UC and has the potential as a dietary supplement to intervene in UC.

Updates on conventional therapies for inflammatory bowel diseases: 5-aminosalicylates, corticosteroids, immunomodulators, and anti-TNF-α

The incidence and prevalence of inflammatory bowel diseases (IBDs) are rapidly increasing worldwide. IBDs are considered an emerging problem not only in Western countries but also in developing counties. The relapses and complications of active IBD mandate various medications. Nevertheless, hospitalization, emergency room visits, or surgery may be required, resulting in a socioeconomic burden. Great advances have been made in the development of new therapeutic options for IBD to achieve induction and maintenance remission. Nevertheless, conventional therapy is still the mainstay in the treatment of IBD. This review article provides an update on recent advances in conventional therapies, including 5-aminosalicylates, corticosteroids, immunomodulators, and anti-tumor necrosis factor-α agents to treat IBD.

Mesalazine and inflammatory bowel disease - From well-established therapies to progress beyond the state of the art

Inflammatory bowel disease incidence has been constantly rising for the past few decades. Current therapies attempt to mitigate its symptoms since no cure is established. The most commonly prescribed drug for these patients is 5-aminosalicylic acid (5-ASA). Due to the low rate and seriousness of side effects compared to other therapies, 5-ASA is still largely prescribed in many stages of inflammatory bowel disease, including scenarios where evidence suggests low effectiveness. Although commercialized formulations have come a long way in improving pharmacokinetics, it is still necessary to design and develop novel delivery systems capable of increasing effectiveness at different stages of the disease. In particular, micro- and nano-sized particles might be the key to its success in Crohn's disease and in more serious disease stages. This review provides an overview on the clinical significance of 5-ASA formulations, its limitations, challenges, and the most recent micro- and nanoparticle delivery systems being designed for its controlled release. Emergent alternatives for 5-ASA are also discussed, as well as the future prospects for its application in inflammatory bowel disease therapies.

Recent advances in mesalamine colonic delivery systems

Background

Increased attention has been focused on the continuous development and improvement of mesalamine colonic specific delivery systems, for the effective treatment of inflammatory bowel diseases; thus enhancing therapeutic efficacy and reducing potential side effects. Mesalamine is a class IV drug, according to the Biopharmaceutics Classification System, used usually to treat inflammation associated with colon related diseases such as Crohn’s disease and ulcerative colitis.

Main text

An ideal colon targeting system aims to deliver a therapeutic agent, selectively and effectively, to the colon. This system should ideally retain the drug release in the upper GI tract (stomach and small intestine); while trigger the drug release in the colon. Several approaches have been used to fabricate formulations to achieve a colon specific delivery of mesalamine such as; time dependent, pH responsive, enzymatic/microbial responsive and ultrasound mediated approaches. This overview outlines the recent advances in mesalamine-colon delivery approaches for the potential treatment of ulcerative colitis and Crohn’ disease.

Conclusion

A combined pH-time dependent delivery system can improve mesalamine colonic drug delivery via employing carriers capable of retarding mesalamine release in the stomach and delivering it at predetermined time points after entering the intestine. The existence of specific enzymes, produced by various anaerobic bacteria present in the colon advocates the advantage of designing enzyme sensitive systems and combining it with pH-time dependent system to improve mesalamine colonic delivery. The use of ultrasound has shown promises to effectively treat inflammatory bowel diseases.

Mesalamine-induced eosinophilic pleural effusion

A 45-year-old woman with a medical history of ulcerative colitis (UC) presented with difficulty in breathing. The patient was diagnosed with UC a month prior to presentation and was started on mesalamine suppository. Chest x-ray (CXR) on presentation showed bilateral pleural effusion, which was confirmed on CT angiogram of the chest. Diagnostic and therapeutic thoracentesis was performed and 0.7 L of pleural fluid was removed from the left side. The pleural fluid analysis was consistent with exudative pleural effusion with eosinophilia. Symptomatic improvement was noted after thoracentesis. Mesalamine was stopped and repeat CXR was obtained on the follow-up visit, which showed no pleural effusion. The Naranjo score was calculated to be 7, indicating that the eosinophilic pleural effusion was most probably secondary to adverse reaction from mesalamine.

An orally administered butyrate-releasing xylan derivative reduces inflammation in dextran sulphate sodium-induced murine colitis

Butyrate has been shown to be effective in ulcerative colitis (UC). However, its oral administration is rare due to its rancid odour and unpleasant taste. In this study, the effect of a butyrate-releasing polysaccharide derivative, xylan butyrate ester (XylB), was evaluated in a dextran sodium sulphate (DSS)-induced UC model in C57BL/6 mice. Linear xylan was extracted from corn cobs. The C-2 and C-3 positions of the linear xylan were esterified with butyrate, forming XylB. The protective and therapeutic effects of XylB against UC were determined in a DSS-induced mouse model. The results showed that XylB treatments reversed the imbalance between pro- and anti-inflammatory cytokines. Moreover, XylB rebalanced the gut microbiota that interfered with DSS treatment and significantly decreased the relative abundance of the genera Oscillibacter, Ruminococcaceae UCG-009, Erysipelatoclostridium, and Defluviitaleaceae UCG-01. XylB increased butyrate content in the colon, upregulated G-protein coupled receptor 109A protein expression, inhibited histone deacetylase (HDAC) activity, and exerted anti-inflammatory activity through autophagy pathway activation and nuclear factor-κB (NF-κB) inhibition. XylB reduces inflammatory intestinal damage in mice, suggesting that it would be a potential drug for the treatment of UC and could be used to overcome the limitations of the oral administration of sodium butyrate.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Inflammatory Bowel Disease

According to recent clinical consensus, pharmacotherapy of inflammatory bowel disease (IBD) is, or should be, personalized medicine. IBD treatment is complex, with highly different treatment classes and relatively few data on treatment strategy. Although thorough evidence-based international IBD guidelines currently exist, appropriate drug and dose choice remains challenging as many disease (disease type, location of disease, disease activity and course, extraintestinal manifestations, complications) and patient characteristics [(pharmaco-)genetic predisposition, response to previous medications, side-effect profile, necessary onset of response, convenience, concurrent therapy, adherence to (maintenance) therapy] are involved. Detailed pharmacological knowledge of the IBD drug arsenal is essential for choosing the right drug, in the right dose, in the right administration form, at the right time, for each individual patient. In this in-depth review, clinical pharmacodynamic and pharmacokinetic considerations are provided for tailoring treatment with the most common IBD drugs. Development (with consequent prospective validation) of easy-to-use treatment algorithms based on these considerations and new pharmacological data may facilitate optimal and effective IBD treatment, preferably corroborated by effectiveness and safety registries.

Effects of Differential Food Patterns on the Pharmacokinetics of Enteric-Coated Mesalazine Tablets in the Same Cohort of Healthy Chinese Volunteers

This study aimed to simultaneously determine mesalazine (5-ASA) and its major metabolite N-Ac-5-ASA in the plasma and to evaluate the impact of different food patterns on the relative bioavailability and pharmacokinetics of a single oral dose of 5-ASA in healthy subjects. In this single-dose, open-label, 3-period, 3-treatment crossover study, the subjects received a single, oral dose of 500-mg enteric-coated mesalazine tablet together with either a low-fat or a high-fat breakfast or under fasting condition (reference). The pharmacokinetic parameters were determined by noncompartmental methods and analyzed with a linear mixed-effect model. The geometric least squares mean ratio for the area under the plasma concentration-time curve from zero to infinity of N-Ac-5-ASA was 1.05 (90% confidence interval [CI], 0.70-1.58) for high-fat/fasted condition and 1.06 (90%CI, 0.82-1.36) for low-fat/fasted condition. The least squares mean ratio of 5-ASA was 0.86 (90%CI, 0.65-1.14) for high-fat/fasted condition and 0.78 (90%CI, 0.60-1.02) for low-fat/fasted condition. All P values were >.05. The mean maximum plasma concentration and the time to reach the maximum plasma concentration of N-Ac-5-ASA were 2084 ng/mL, 8 hours; 2639 ng/mL, 11 hours, and 2409 ng/mL, 9 hours for fasted, high-fat, and low-fat, respectively. The values of 5-ASA were 1950 ng/mL, 7 hours; 2869 ng/mL, 9 hours; and 2837 ng/mL, 8 hours for fasted, high-fat, and low-fat condition. 5-ASA was well tolerated under all 3 conditions. Food delayed the absorption of 5-ASA, especially a high-fat meal. Therefore, enteric-coated mesalazine tablets should be taken before meals to avoid causing patients slow response and any effect of food on its efficacy.

Regulatory framework on bioequivalence criteria for locally acting gastrointestinal drugs: the case for oral modified release mesalamine formulations

INTRODUCTION

Bioequivalence testing for locally acting gastrointestinal drugs is a challenging issue for both regulatory authorities and pharmaceutical industries. The international regulatory framework has been characterized by the lack of specific bioequivalence tests that has generated a negative impact on the market competition and drug use in clinical practice. Areas covered: This review article provides an overview of the European Union and United States regulatory frameworks on bioequivalence criteria for locally acting gastrointestinal drugs, also discussing the most prominent scientific issues and advances that has been made in this field. A focus on oral modified release mesalamine formulations will be also provided, with practical examples of the regulatory pathways followed by pharmaceutical companies to determine bioequivalence. Expert commentary: The development of a scientific rationale to demonstrate bioequivalence in this field has been complex and often associated with uncertainties related to scientific and regulatory aspects. Only in recent years, thanks to advanced knowledge in this field, the criteria for bioequivalence assessment are undergoing substantial changes. This new scenario will likely result in a significant impact on pharmaceutical companies, promoting more competition through a clearer regulatory approach, conceived for streamlining the demonstration of therapeutic equivalence for locally acting gastrointestinal drugs.

The safety of non-biological treatments in Ulcerative Colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with a relapsing-remitting course that determines significant morbidity and can associate with local complications and/or extra-intestinal manifestations. Pharmacological therapies are often required for a lifetime with possible risks of toxicity and side effects. Areas covered: Non-biological therapies (i.e. aminosalicylates, corticosteroids and immunosuppressive drugs) are widely used in UC patients for controlling the active phases of the disease and maintaining remission. Expert Opinion: Aminosalycilates have a good safety profile with a low risk of idiosyncrasic reactions. In contrast, the use of corticosteroids and immunosuppressive drugs can associate with unacceptable side effects, some of which are potentially life threatening. Mechanisms underlying the development of these side effects are not fully understood and strategies aimed to prevent them have not yet been standardized. However, clinicians should monitor the patients during therapy to recognize the adverse events at an early stage of the occurrence. New drugs that selectively target molecules involved in the amplification of the ongoing mucosal inflammation are currently under investigation. Preliminary data indicate that such compounds have better overall safety and tolerability than corticosteroids and immunosuppressive drugs.

Red-Brown Urine Discolouration in Two Patients Taking Mesalamine

A 38-year-old male and a 36-year-old female experienced red-brown urine discolouration after 2 and 3 days, respectively, during the use of mesalamine for inflammatory bowel disease. Both patients mentioned that the urine discoloured after contact with sodium hypochlorite detergent in toilet water. Mesalamine and the inactive metabolite N-acetyl-5-aminosalicylic acid are primarily excreted in the urine. We hypothesised a possible reaction with sodium hypochlorite and/or light. Naranjo assessment scores of 9 and 6 were obtained for the reports, indicating a certain and probable relationship, respectively, between the red-brown urine discolouration and the use of the suspect drug mesalamine. Knowledge of this harmless reaction is desirable to avoid unnecessary physical examination and worry.

Pharmacokinetics in Wistar Rats of 5-[(4-Carboxybutanoyl)Amino]-2-Hydroxybenzoic Acid: A Novel Synthetic Derivative of 5-Aminosalicylic Acid (5-ASA) with Possible Anti-Inflammatory Activity

5-[(4-carboxybutanoyl)amino]-2-hydroxybenzoic acid (C2) is a novel synthetic derivative of 5-aminosalicylic acid (5-ASA), which is currently being evaluated ex vivo as an anti-inflammatory agent and has shown satisfactory results. This study aimed to obtain the pharmacokinetic profiles, tissue distribution and plasma protein binding of C2 in Wistar Rats. Additionally, an HPLC method was developed and validated to quantify C2 in rat plasma. The pharmacokinetic profiles of intragastric, intravenous and intraperitoneal administration routes at singles doses of 100, 50, and 100 mg/kg, respectively, were studied in Wistar rats. The elimination half-life of intravenously administered C2 was approximately 33 min. The maximum plasma level of C2 was reached approximately 24 min after intragastric administration, with a Cmax value of 2.5 g/mL and an AUCtot value of 157 μg min-1/mL; the oral bioavailability was approximately 13%. Following a single intragastric or oral dose (100 mg/kg), C2 was distributed and detected in all examined tissues (including the brain and colon). The results showed that C2 accumulates over time. The plasma protein binding results indicated that the unbound fraction of C2 at concentrations of 1 to 20 μg/mL ranged from 89.8% to 92.5%, meaning that this fraction of C2 is available to cross tissues. Finally, the blood-plasma partitioning (BP ratio) of C2 in rat plasma was 0.71 and 0.6 at concentrations of 5 and 10 μg/mL, respectively, which indicates that C2 is free in the plasmatic phase and not inside blood cells. The results of this study suggest that a fraction of the administered C2 dose is absorbed in the stomach, and the fraction that is not absorbed reaches the small intestine and colon. This distribution constitutes the main advantage of C2 compared with 5-ASA for the treatment of ulcerative colitis (UC) and Crohn's disease (CD).

In vitro biorelevant models for evaluating modified release mesalamine products to forecast the effect of formulation and meal intake on drug release

AIMS

Postprandial administration of solid oral dosage forms greatly changes the dissolution environment compared to fasted state administration. The aims of this study were to investigate and forecast the effect of co-administration of a meal on drug release for delayed and/or extended release mesalamine formulations as well as design of in vitro tests to distinguish among formulations in a biorelevant way.

METHODS

Five different mesalamine formulations (Asacol® 400 mg, Mezavant® 1200 mg, Pentasa® 500 mg and Salofalk® in the 250 mg and 500 mg strengths) were investigated with biorelevant dissolution methods using the USP apparatus III and USP apparatus IV (open loop mode) under both fasted and fed state conditions, as well as with the dissolution methods described in pharmacopeia for delayed and extended release mesalamine products.

RESULTS

Using the biorelevant experimental conditions proposed in this study, changes in release in the proximal gut due to meal intake are forecast to be minimal for Asacol®, Mezavant®, Pentasa® and Salofalk® 500 mg, while for Salofalk® 250 mg release was predicted to occur much earlier under fed state conditions. The USP apparatus III generally tended to result in faster dissolution rates and forecast more pronounced food effects for Salofalk® 250 mg than the USP apparatus IV. The biorelevant dissolution gradients were also able to reflect the in vivo behavior of the formulations.

CONCLUSIONS

In vitro biorelevant models can be useful in the comparison of the release behavior from different delayed and extended release mesalamine formulations as well as forecasting effects of concomitant meal intake on drug release.

Infliximab is superior to other biological agents for treatment of active ulcerative colitis: A meta-analysis

AIM: To compare the efficacy and safety of biological agents for the treatment of active ulcerative colitis (UC).

METHODS: PubMed, MEDLINE, EMBASE and the Cochrane library were searched to screen relevant articles from January 1996 to August 2014. The mixed treatment comparison meta-analysis within a Bayesian framework was performed using WinBUGS14 software. The proportions of patients reaching clinical response, clinical remission and mucosal healing in induction and maintenance phases were analyzed as efficacy indicators. Serious adverse events in maintenance phase were analyzed as safety indicators.

RESULTS: The meta-analysis results showed that biological agents achieved better clinical response, clinical remission and mucosal healing than placebo. Indirect comparison indicated that in induction phase, infliximab was more effective than adalimumab in inducing clinical response (OR = 0.41, 95%CI: 0.29-0.57), clinical remission (OR = 0.33, 95%CI: 0.19-0.56) and mucosal healing (OR = 0.33, 95%CI: 0.19-0.56), and golimumab in inducing clinical response (OR = 0.66, 95%CI: 0.39-2.33) and mucosal healing (OR = 2.15, 95%CI: 1.18-4.22). No significant difference was found between placebo and biological agents regarding their safety.

CONCLUSION: All biological agents were superior to placebo for UC treatment in both induction and maintenance phases with a similar safety profile, and infliximab had a better clinical effect than the other biological agents.

Pediatric ulcerative colitis: a practical guide to management

Ulcerative colitis (UC) is a chronic inflammatory disorder of the gastrointestinal tract of unknown etiology that frequently presents in the pediatric population. The evaluation of pediatric UC involves excluding infection, and a colonoscopy that documents the clinical and histologic features of chronic colitis. Initial management of mild UC is typically with mesalamine therapy for induction and maintenance. Moderate UC is often initially treated with oral prednisone. Depending on disease severity and response to prednisone, maintenance options include mesalamine, mercaptopurine, azathioprine, infliximab, or adalimumab. Severe UC is typically treated with intravenous corticosteroids. Corticosteroid nonresponders should either undergo a colectomy or be treated with second-line medical rescue therapy (infliximab or calcineurin inhibitors). The severe UC patients who respond to medical rescue therapy can be maintained on infliximab or thiopurine, but 1-year remission rates for such patients are under 50 %. These medications are discussed in detail along with the initial work-up and a treatment algorithm.

Budesonide is more effective than mesalamine or placebo in short-term treatment of collagenous colitis

BACKGROUND & AIMS

Studies reporting that budesonide is effective for the treatment of collagenous colitis have been small and differed in efficacy measures. Mesalamine has been proposed as a treatment option for collagenous colitis, although its efficacy has never been investigated in placebo-controlled trials. We performed a phase 3, placebo-controlled, multicenter study to evaluate budesonide and mesalamine as short-term treatments for collagenous colitis.

METHODS

Patients with active collagenous colitis were randomly assigned to groups given pH-modified release oral budesonide capsules (9 mg budesonide once daily, Budenofalk, n = 30), mesalamine granules (3 g mesalamine once daily, Salofalk, n = 25), or placebo for 8 weeks (n = 37) in a double-blind, double-dummy fashion. The study was conducted in 31 centers (hospital clinics and private practices) in Germany, Denmark, Lithuania, Spain, and the United Kingdom. The primary end point was clinical remission at 8 weeks defined as ≤ 3 stools per day. Secondary end points included clinical remission at 8 weeks, according to the Hjortswang-Criteria of disease activity, taking stool consistency into account.

RESULTS

A greater percentage of patients in the budesonide group were in clinical remission at week 8 than the placebo group (intention-to-treat analysis, 80.0% vs 59.5%; P = .072; per-protocol analysis, 84.8% vs 60.6%; P = .046). Based on the Hjortswang-Criteria, 80.0% of patients given budesonide achieved clinical remission compared with 37.8% of patients given placebo (P = .0006); 44.0% of patients given mesalamine achieved clinical remission, but budesonide was superior to mesalamine (P = .0035). Budesonide significantly improved stool consistency and mucosal histology, and alleviated abdominal pain. The rate of adverse events did not differ among groups.

CONCLUSIONS

Oral budesonide (9 mg once daily) is effective and safe for short-term treatment of collagenous colitis. Short-term treatment with oral mesalamine (3 g once daily) appears to be ineffective. ClinicalTrials.gov number, NCT00450086.

Safety of 5-Aminosalicylic Acid Derivatives in Patients with Sensitivity to Acetylsalicylic Acid and Nonsteroidal Anti-inflammatory Drugs

BACKGROUND

One of the cornerstones of the management of inflammatory bowel disease is the use of 5-aminosalicylic acid (5-ASA) compounds for treatment of flares and as maintenance therapy during remission. There are concerns about using 5-ASA in patients with a history of hypersensitivity to acetylsalicylic acid (ASA).

OBJECTIVE

To assess the literature with respect to the safety of 5-ASA compounds in patients with documented sensitivity to ASA or nonsteroidal anti-inflammatory drugs (NSAIDs).

DATA SOURCES

A literature search was conducted in the MEDLINE and Embase databases, using various search terms, including "aminosalicylic acids", "non-steroidal anti-inflammatory agents," "hypersensitivity", and "allergy". The search was limited to articles (of any study design) published in English. Abstracts, full articles, and reference lists from retrieved articles were assessed to identify further relevant literature.

STUDY SELECTION AND DATA EXTRACTION

Of 485 citations identified in the initial search, 4 case reports were relevant to the study objective and were analyzed in detail.

DATA SYNTHESIS

Three of the case reports described the successful use of 5-ASA compounds in patients with prior sensitivity to ASA or an NSAID. The fourth report described a reaction to 5-ASA in a patient who had previously tolerated ASA. All of the reports were limited by lack of investigation into the validity of the reported sensitivity to ASA or 5-ASA.

CONCLUSIONS

There is a dearth of evidence demonstrating cross-reactivity between ASA or NSAID and 5-ASA. This lack of information may relate to the mechanism of action of 5-ASA. This agent controls inflammation by inhibiting prostaglandin E2 and leukotrienes. In contrast, ASA-induced or NSAID-induced reactions are due to inhibition of the cycloxygenase-1 enzyme and subsequent release of histamine and synthesis of leukotrienes. Further reports describing the safety of 5-ASA use in patients with sensitivity to ASA or NSAIDs are needed before safety in this situation can be definitively determined. In patients with sensitivity to ASA or NSAID who require 5-ASA, a test dose of 5-ASA (to rule out potential cross-reactivity) or further investigation of the ASA or NSAID sensitivity is recommended.

Treatment of ulcerative colitis

PURPOSE OF REVIEW

Ulcerative colitis is a chronic inflammatory disease of the colon of unknown cause that is characterized by alternating intervals of active and inactive disease in 80-90% of patients. The primary goal of treatment is to induce and maintain remission using therapy tailored to the individual patient. The purpose of this review was to describe the management of ulcerative colitis with emphasis on the use of anti-tumor necrosis factor (TNF) agents.

RECENT FINDINGS

Recent research has shown that new anti-TNF agents, adalimumab (ADA) and golimumab, are effective in induction of remission and maintenance of remission in patients with extensive ulcerative colitis. In a recent study, infliximab was found to have comparable efficacy to cyclosporine in treatment of acute severe refractory to corticosteroids ulcerative colitis.

SUMMARY

Anti-TNF therapy should be initiated in patients with acute severe refractory to corticosteroids ulcerative colitis and in patients with moderate-to-severe ulcerative colitis who are not responsive to conventional treatment with aminosalicylates, corticosteroids and immune modulators. Alternatives to infliximab are ADA and golimumab. Future research is needed to further assess the long-term efficacy and safety of ADA and golimumab in ulcerative colitis.

[Rescue therapy with sulfasalazine prior to immunosuppressive or biological agents in ulcerative colitis poorly controlled with mesalazine]

INTRODUCTION

In ulcerative colitis, aminosalicylates are the mainstay of maintenance therapy. Sulfasalazine was the first aminosalicylic used in the maintenance therapy of this disease. Later, mesalazine was preferred due to its supposedly better tolerability. However, recent studies indicate certain benefits of the use of sulfasalazine because of its possible superior effectiveness. The aim of this study was to determine whether patients with ulcerative colitis poorly controlled by mesalazine as maintenance therapy respond to sulfasalazine, thus avoiding the use of immunosuppressive or biological therapies.

METHODS

The Inflammatory Bowel Disease Clinic of the Ramón y Cajal Hospital maintains a database in which all drug exposures are registered. We selected patients poorly controlled with mesalazine who had received sulfasalazine as rescue maintenance therapy. We determined the percentage of patients poorly controlled with mesalazine who responded to sulfasalazine.

RESULTS

Of 415 patients with ulcerative colitis, 49 had been treated with sulfasalazine at some time. Of these, sulfasalazine was selected as an alternative therapy due to poor disease control with mesalazine. The median duration of mesalazine therapy until the switch was 20.8 months, with a median dose of 3.35 g/day. In 21 of the 31 patients (67.7%), sulfasalazine was able to control symptoms and maintain remission.

CONCLUSION

Despite the limitations of this study, we found that 67.7% of patients with ulcerative colitis poorly controlled with mesalazine responded to a switch to sulfasalazine. These patients would normally have progressed to immunosuppressive, biological or surgical treatments. This option merits further studies. Meanwhile sulfasalazine should not be forgotten in the management of ulcerative colitis.

Design, Synthesis, and Testing of a Molecular Truck for Colonic Delivery of 5-Aminosalicylic Acid

A molecular scaffold bearing eight terminal alkyne groups was synthesized from sucrose. Eight copies of an azide-terminated, azo-linked precursor to 5-aminosalicylic acid were attached to the scaffold via copper(I)-catalyzed azide-alkyne cycloaddition. The resulting compound was evaluated in a DSS model of colitis in BALB/c mice against sulfasalazine as a control. Two independent studies verified that the novel pro-drug, administered in a dose calculated to result in an equimolar 5-ASA yield, outperformed sulfasalazine in terms of protection from mucosal inflammation and T cell activation. A separate study established that 5-ASA appeared in feces produced 24-48 hours following administration of the pro-drug. Thus, a new, orally administered pro-drug form of 5-aminosalicylic acid has been developed and successfully demonstrated.

Mesalamine in the treatment and maintenance of remission of ulcerative colitis

Ulcerative colitis (UC) is a chronic disease of the GI tract that is characterized by mucosal inflammation in the colon. Mesalamine (mesalazine) is a 5-aminosalicylic acid compound that is the first-line treatment for patients with mild-to-moderate UC. There are multiple formulations of mesalamine available, primarily differentiated by their means of delivering active mesalamine to the colon. Mesalamine has been demonstrated in randomized controlled trials to induce both clinical response and remission, and maintain clinical remission, in these patients. It has few serious adverse effects and is generally well tolerated by patients. The main areas of uncertainty with use of mesalamine in patients with UC center on the optimal dose for induction of response, how to maintain patient adherence and the role of mesalamine in cancer chemoprophylaxis. Generic forms of mesalamine have yet to be approved by regulatory bodies in the USA.