Mucosal 5-aminosalicylic acid concentration inversely correlates with severity of colonic inflammation in patients with ulcerative colitis

Optimization, cellular uptake, and in vivo evaluation of Eudragit S100-coated bile salt-containing liposomes for oral colonic delivery of 5-aminosalicylic acid

Eudragit S100-coated bile salt-containing liposomes were prepared and optimized by experimenting with different variables, including bile salt type and concentration, and the method of incorporation into liposomes using a model hydrophilic compound, 5-aminosalicylic acid (5-ASA). After optimizing the formulation, cellular uptake, and animal pharmacokinetic experiments were performed. The inclusion of sodium glycocholate (SG) into liposomes decreased liposome particle size and entrapment efficiency significantly but had no effect on zeta potential. The method of incorporating SG into the lipid or aqueous phase of the liposome did not notably impact the characteristics of the liposomes but the hydration media had a substantial effect on the entrapment efficiency of 5-ASA. In vitro drug release in different fluids simulating distinct gastrointestinal tract sections, indicated pH-dependent disintegration of the coating layer of coated SG-containing liposomes. The majority of the drug was retained when subjected to simulated gastric fluid (SGF) and fed-state simulated intestinal fluid (FeSSIF) (≈ 37% release after 2 h in SGF pH 1.2, followed by 3 h in FeSSIF pH 5). The remaining drug was subsequently released in phosphate-buffered saline pH 7.4 (≈ 85% release within 24 h). Increasing SG concentration in the liposomes decreased the amount of drug released in FeSSIF. Similar results were observed when SG was replaced with sodium taurocholate. Cellular uptake studies in Caco-2 cells demonstrated that all liposomal formulations (conventional liposomes, bile salt-containing liposomes, and coated bile salt-containing liposomes) have shown to be equally effective at increasing the cellular uptake compared to free fluorescein solution. In the pharmacokinetic study, coated bile salt-containing liposomes showed a lower Cmax and prolonged residence in the gastrointestinal tract in comparison to conventional liposomes. Taken together, these findings suggest that the polymer-coated bile salt-containing liposomes have the potential to serve as a drug delivery system targeted at the colon.

Potential of Mesalazine Therapeutic Drug Monitoring by Measuring Fecal Excretion in Patients With Ulcerative Colitis

BACKGROUND

Therapeutic drug monitoring of mesalazine (5-ASA) in patients with ulcerative colitis is unavailable. Mucosal 5-ASA concentrations are assumed to be higher during remission, but biopsy is not practical. Therefore, we investigated the feasibility of measuring mesalazine levels in feces. To explore the potential role of fecal mesalazine measurements in therapeutic drug monitoring, we compared the dry fecal concentration and daily fecal excretion of 5-ASA and its metabolite N-acetyl-5-ASA in patients with ulcerative colitis with active and quiescent disease.

METHODS

Adults with ulcerative colitis on oral mesalazine and scheduled for colonoscopy were eligible for inclusion in this cross-sectional study. Stool and urine samples were collected for 48 and 24 hours, respectively, and rectal biopsies were performed. (N-acetyl-)5-ASA was measured using mass spectrometry. Biochemically active disease was defined as a fecal calprotectin level above 100 mcg/g and endoscopically active disease as any activity following the endoscopic Mayo score (≥1).

RESULTS

Approximately 28 patients were included in the study. Daily fecal excretion of (N-acetyl-)5-ASA did not differ between patients with (n = 13) and without (n = 15) endoscopically active disease [median 572 mg/d versus 597 mg/d ( P = 0.86) for 5-ASA and 572 mg/d versus 554 mg/d ( P = 0.86) for N-acetyl-5-ASA]. The same applied to the fecal concentration [median 9.7 mcg/mg dry weight versus 10.3 ( P = 0.53) and 12.0 versus 9.9 ( P = 0.89)]. The results were comparable when the biochemical disease activity definition was used. The mucosal concentrations and urinary excretion of (N-acetyl-)5-ASA did not differentiate between quiescent and active activity.

CONCLUSIONS

Fecal (N-acetyl-)5-ASA measurements do not correlate with disease activity, which renders it an unsuitable tool for therapeutic drug monitoring of mesalazine.

Therapeutic Drug Monitoring of Infliximab in Acute Severe Ulcerative Colitis

Therapeutic drug monitoring (TDM) is a useful strategy in ulcerative colitis (UC). Nearly a quarter of UC patients will experience acute severe UC (ASUC) in their lifetime, including 30% who will fail first-line corticosteroid therapy. Steroid-refractory ASUC patients require salvage therapy with infliximab, cyclosporine, or colectomy. Fewer data are available for the use of TDM of infliximab in ASUC. The pharmacokinetics of ASUC make TDM in this population more complex. High inflammatory burden is associated with increased infliximab clearance, which is associated with lower infliximab drug concentrations. Observational data support the association between increased serum infliximab concentrations, lower clearance, and favorable clinical and endoscopic outcomes, as well as decreased rates of colectomy. Data regarding the benefit of accelerated or intensified dosing strategies of infliximab-as well as target drug concentration thresholds-in ASUC patients remain more equivocal, though limited by their observational nature. Studies are underway to further evaluate optimal dosing and TDM targets in this population. This review examines the evidence for TDM in patients with ASUC, with a focus on infliximab.

cRGD peptide incorporated with patchouli alcohol loaded silk fibroin nanoparticles for enhanced targeting of inflammatory sites in colitis

The combination therapy of strengthening inflammation regression and mucosal repair may overcome the "therapeutic ceiling" of ulcerative colitis (UC). However, poor targeting is an outstanding challenge in the preparation of drug delivery systems for UC treatment. Here, we developed anti-inflammatory drug (patchouli alcohol, PA)-loaded nanoparticles (NPs) derived from natural silk fibroin (SF) and subjected to surface functionalization with cyclo RGD peptide (cRGD). Self-assembled SF NPs realized sustained drug release. Meanwhile, cRGD functionalization yielded notably targeted drug delivery to inflamed colon, and thereby enhanced the anti-inflammatory and barrier repair capabilities of NPs. Moreover, cRGD-PASFNs regulated innate immune responses and exerted a potent therapeutic efficacy against acute colitis. Surprisingly, the cRGD-PASFNs also modulated the abnormal level of amino acids which are crucial to the integrity of the intestinal barrier. Additionally, oral delivery of this nanomedicine displayed an excellent safety profile in the mouse model. This study confers confidence for the further development of targeted precision therapy for UC and other inflammatory diseases.

pH-dependent vs. constant release of mesalazine in the treatment of ulcerative colitis: Do drug delivery concepts determine therapeutic efficacy? (Review)

Inflammatory bowel diseases (IBD) have developed to become a major global health problem. Ulcerative colitis (UC) is one of two main types of IBD, and >90% of patients suffering from mild or moderate forms of UC are treated with mesalazine, a well-tolerated and cost-effective drug. To allow oral administration, the drug has to be protected from resorption before it can reach the affected sites in the colon. The drug is therefore released from most currently used medications either constantly slow (time-dependent) or triggered by an increased pH during gastrointestinal transition. Both variants are widely used in clinical practice and it is surprising that they have not yet been compared directly in a large clinical study. In this overview, the evidence that may suggest preferential use of one type of mesalazine formulation over the other in general or for defined subgroups of patients is summarized and evaluated. Data from in vitro modelling of drug release and measurements of drug concentrations in colonic mucosa suggest that in many cases, constant release and pH-dependent formulations are of similar therapeutic efficiency; however, pH-triggered release may be superior in patients with proctitis-type UC or sites of inflammation in the proximal colon. Additionally, patients with a long gastric residence time, slow small intestinal transition, disease-related diarrhea or sensitivity to systemic adverse effects may benefit more from pH-dependent release formulations. In general, medications based on both concepts show similar efficacies, but the pH-dependent release formulations seem to be more robust in the treatment of a not further classified group of patients with UC. Future comparative clinical studies are required to clearly define the subgroups of patients that should be treated preferably with constant or pH-dependent release formulations of mesalazine.

Factors associated with the persistence of oral 5-aminosalicylic acid monotherapy in ulcerative colitis: a nationwide Norwegian cohort study

BACKGROUND

Oral 5-aminosalicylic acid (5-ASA) is the mainstay treatment of ulcerative colitis (UC) and therapy with oral 5-ASA is associated with beneficial outcomes. We have examined factors associated with the persistence of oral 5-ASA treatment in a national cohort of UC patients.

METHODS

Patients with newly diagnosed UC from 2010 to 2014 using oral 5-ASA monotherapy were identified by combining data from the Norwegian Patient Registry and the Norwegian Prescription Database. The median follow-up time was 1029 days. Drug persistence was defined as duration of oral 5-ASA preparation as monotherapy. Non-persistence of a oral 5-ASA preparation as monotherapy was defined as stopping oral 5-ASA, initiation of any further anti-inflammatory treatment including a course of glucocorticoids and a change to another oral 5-ASA preparation. Drug persistence was analyzed using the Kaplan-Meier method and influence of covariates on drug persistence was analyzed with the Cox proportional hazard model.

RESULTS

A total of 3421 patients were identified. The overall median 5-ASA drug persistence was 179 days. In univariate analyses, persistence was associated with preparation type and high-dose treatment, while oral glucocorticoid use or hospitalization around the start of oral 5-ASA were associated with shorter 5-ASA persistence. In multivariate analyses, oral glucocorticoids [HR 1.67 (1.54-1.80), p < 0.005] and hospitalization around start of 5-ASA [HR 1.23 (1.14-1.34), p < 0.005] were associated with non-persistence, whereas high dose (⩾3 g/day) 5-ASA was associated with longer persistence [HR 0.68 (0.65-0.71), p < 0.005].

CONCLUSION

High-dose treatment with oral 5-ASA was associated with longer persistence of oral 5-ASA monotherapy, whereas the presence of factors indicating more severe disease around initiation of 5-ASA monotherapy was associated with a shorter persistence.

Suppository treatment in ulcerative proctitis

Ulcerative proctitis (UP) is a common form of ulcerative colitis (UC), the number of patients with UP is increasing. Suppository treatment containing mesalamine is usually the first-line choice for mild to moderate UP, here, we review the publications on mesalamine suppository in UP, to better understand its dosage, duration of therapy and adverse events in both induction and maintenance phases. We also review articles on budesonide, beclomethasone, tacrolimus, herbal medicine and acetarsol suppositories in UP, to present therapeutic strategies for patients with UP refractory to mesalamine suppository.

Colonic Gene Expression and Fecal Microbiota in Diarrhea-predominant Irritable Bowel Syndrome: Increased Toll-like Receptor 4 but Minimal Inflammation and no Response to Mesalazine

Background/Aims

Diarrhea-predominant irritable bowel syndrome (IBS-D) has been previously associated with evidence of immune activation and altered microbiota. Our aim is to assess the effect of the anti-inflammatory agent, mesalazine, on inflammatory gene expression and microbiota composition in IBS-D.

Methods

We studied a subset of patients (n = 43) from a previously published 12-week radomized placebo-controlled trial of mesalazine. Mucosal biopsies were assessed by immunohistochemistry and reverse transcription-polymerase chain reaction for a range of markers of inflammation, altered permeability, and sensory receptors including Toll-like receptors (TLRs) at randomization after treatment. All biopsy data were compared to 21 healthy controls. Patient’s stool microbiota composition was analysed through 16S ribosomal RNA sequencing.

Results

We found no evidence of increased immune activation compared to healthy controls. However, we did find increased expression of receptors in both sensory pathways and innate immune response including TLR4. Higher TLR4 expression was associated with greater urgency. TLR4 expression correlated strongly with the expression of the receptors bradykinin receptor B2, chemerin chemokine-like receptor 1, and transient receptor potential cation channel, subfamily A, member 1 as well as TLR4’s downstream adaptor myeloid differentiation factor 88. Mesalazine had minimal effect on either gene expression or microbiota composition.

Conclusions

Biopsies from a well-characterized IBS-D cohort showed no substantial inflammation. Mesalazine has little effect on gene expression and its previous reported effect on fecal microbiota associated with much greater inflammation found in inflammatory bowel diseases is likely secondary to reduced inflammation. Increased expression of TLR4 and correlated receptors in IBS may mediate a general increase in sensitivity to external stimuli, particularly those that signal via the TLR system.

The Polyphosphate Kinase of Escherichia coli Is Required for Full Production of the Genotoxin Colibactin

Colibactin induces DNA damage in mammalian cells and has been linked to the virulence of Escherichia coli and the promotion of colorectal cancer (CRC). By looking for mutants attenuated in the promoter activity of clbB encoding one of the key enzymes for the production of colibactin, we found that a mutant of the gene coding for the polyphosphate kinase (PPK) produced less colibactin than the parental strain. We observed this phenotype in different strains ranging from pathogens responsible for meningitis, urinary tract infection, or mouse colon carcinogenesis to the probiotic Nissle 1917. We confirmed the role of PPK by using an inhibitor of PPK enzymatic activity, mesalamine (also known as 5-aminosalicylic acid). Interestingly, mesalamine has a local anti-inflammatory effect on the epithelial cells of the colon and is used to treat inflammatory bowel disease (IBD). Upon treatment with mesalamine, a decreased genotoxicity of colibactin-producing E. coli was observed both on epithelial cells and directly on purified DNA. This demonstrates the direct effect of mesalamine on bacteria independently from its anti-inflammatory effect on eukaryotic cells. Our results suggest that the mechanisms of action of mesalamine in treating IBD and preventing CRC could also lie in the inhibition of colibactin production. All in all, we demonstrate that PPK is required for the promoter activity of clbB and the production of colibactin, which suggests that PPK is a promising target for the development of anticolibactin and antivirulence strategies.IMPORTANCE Colibactin-producing E. coli induces DNA damage in eukaryotic cells and promotes tumor formation in mouse models of intestinal inflammation. Recent studies have provided strong evidence supporting the causative role of colibactin in human colorectal cancer (CRC) progression. Therefore, it is important to understand the regulation of the production of this genotoxin. Here, we demonstrate that polyphosphate kinase (PPK) is required for the promoter activity of clbB and the production of colibactin. Interestingly, PPK is a multifunctional player in bacterial virulence and stress responses and has been proposed as a new target for developing antimicrobial medicine. We observed inhibition of colibactin production by using a previously identified PPK inhibitor (i.e., mesalamine, an anti-inflammatory drug commonly prescribed for inflammatory bowel diseases). These data brought us a new perspective on the regulatory network of colibactin production and provided us a clue for the development of anticolibactin strategies for CRC treatment/prophylaxis.

Mucosal concentrations of N-acetyl-5-aminosalicylic acid related to endoscopic activity in ulcerative colitis patients with mesalamine

BACKGROUND AND AIM

5-Aminosalicylic acid (5-ASA) is a fundamental treatment for mild-to-moderate ulcerative colitis (UC). 5-ASA is taken up into the colonic mucosa and metabolized to N-acetyl-5-ASA (Ac-5-ASA). Few studies have assessed whether mucosal 5-ASA and Ac-5-ASA concentrations are associated with endoscopic remission. This study aimed to investigate differences in 5-ASA and Ac-5-ASA concentrations according to endoscopic activity.

METHODS

This single-center, prospective, cross-sectional study was conducted between March 2018 and February 2019. UC patients who were administered with 5-ASA medication for at least 8 weeks before sigmoidoscopy were enrolled. Mucosal 5-ASA and Ac-5-ASA concentrations were measured using liquid chromatography with tandem mass spectrometry. The primary endpoint was defined as the difference in mucosal concentrations of 5-ASA and Ac-5-ASA, according to the Mayo endoscopic subscore (MES).

RESULTS

Mucosal concentrations were analyzed in 50 patients. In the sigmoid colon, the median 5-ASA concentration in patients with MES of 0 (17.3 ng/mg) was significantly higher than MES ≥ 1 (6.4 ng/mg) (P = 0.019). The median 5-ASA concentrations in patients with Ulcerative Colitis Endoscopic Index of Severity ≤ 1 (16.4 ng/mg) were also significantly higher than in patients with Ulcerative Colitis Endoscopic Index of Severity ≥ 2 (4.63 ng/mg) (P = 0.047). In the sigmoid colon, the concentration of Ac-5-ASA was higher in patients with MES of 0 (21.2 ng/mg) than in patients with MES ≥ 1 (5.81 ng/mg) (P = 0.022).

CONCLUSIONS

The present study showed that mucosal Ac-5-ASA concentrations, as well as 5-ASA concentrations, are higher in UC patients with endoscopic remission. Ac-5-ASA may be useful for a biomarker of 5-ASA efficacy.

Effect of acid-reducing agents on clinical relapse in ulcerative colitis with pH-dependent-released 5-aminosalicylic acid: a multicenter retrospective study in Japan

BACKGROUND/AIMS

5-Aminosalicylic acid (5-ASA) is a basic drug for inducing and maintaining remission for ulcerative colitis. One of its formulations has a coating with a pH-dependent degradation that ensures the release 5-ASA at the terminal ileum. No evidence has been shown concerning the effects of proton pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs) on the clinical course of ulcerative colitis patients in remission. The present study assessed the effect of PPIs or H2RAs on the relapse of ulcerative colitis patients in clinical remission maintained by pH-dependent released 5-ASA.

METHODS

Ulcerative colitis patients who had been prescribed time- or pH-dependent-released 5-ASA between January 2015 and December 2018 were enrolled in this multicenter retrospective study. The period of remission until relapse occurred was analyzed among the patients taking time-dependent-released 5-ASA or pH-dependent-released 5-ASA with/without PPIs or H2RAs.

RESULTS

One hundred and nineteen patients were analyzed in this study. In the primary endpoint, the relapse rate was higher in patients taking pH-dependent-released 5-ASA and PPIs or H2RAs than in those taking the pH-dependent-released 5-ASA without PPIs or H2RAs, while the relapse rate was similar in patients taking the time-dependent-released 5-ASA with or without PPIs or H2RAs concomitantly. Patients with a short duration of disease and middle-aged patients more frequently showed relapse with PPIs or H2RAs than the other patients.

CONCLUSIONS

The coadministration of PPIs or H2RAs affects the clinical course of ulcerative colitis in remission maintained by pH-dependent-released 5-ASA.

Prediction of treatment failure during infliximab induction therapy in inflammatory bowel disease patients based on pharmacokinetic and pharmacodynamic modeling

BACKGROUND

In infliximab (IFX) treatment for Crohn's disease (CD) and ulcerative colitis (UC), it is difficult to predict treatment failure during the induction phase. In the present study for optimal IFX treatment, we attempted to estimate serum IFX concentration and clinical response in individual patients during the induction phase to predict the indication of therapeutic effect and the possibility of treatment failure in the maintenance phase.

METHODS

We estimated pharmacokinetic and pharmacodynamic (PK/PD) parameters and predicted the serum IFX concentration and clinical response using a PK/PD model and Markov chain Monte Carlo Bayesian analysis method during the induction phase. Then, we determined whether the indication of therapeutic effect between predicted and observed clinical response were matched during the maintenance phase.

RESULTS

Data obtained from 15 patients were analyzed. The correlation between predicted and observed values of serum IFX concentration (Pearson product-moment correlation coefficient, 0.700; P < 0.0001, n = 68) and clinical response of CD patients (0.790; P < 0.0001, n = 25) and UC patients (0.702; P = 0.0004, n = 21) were significantly high. The indication of therapeutic effect at the final time point of each patient (from day 115 to day 203) were successfully predicted in 14 of 15 patients (93.3%).

CONCLUSIONS

This study presents prediction of serum IFX concentration and clinical response in individual patients during induction therapy, with presumption of the indication of therapeutic effect and the treatment failure in the maintenance phase. Our results show the possibility of optimizing IFX therapy during the induction phase.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.

Recommendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on topical therapy in ulcerative colitis

Although most patients with ulcerative colitis should be given topical treatment, different studies have shown that they are underused in clinical practice. The purpose of this article is to answer 10 specific questions about which drugs are available for topical use in the treatment of ulcerative colitis, and their characteristics in terms of formulation, dosage, presentation, application and proximal distribution of rectal-administered drugs. The efficacy of available topical drugs and the benefits of combining different formulations and routes of administration, and their usefulness during disease remission are evaluated. Finally, a series of recommendations addressed to patients are given on the correct application of topical treatment.

Solving the questions regarding 5-aminosalitylate formulation in the treatment of ulcerative colitis

5-aminosalicylate is a fundamental treatment for patients with ulcerative colitis with mild-to-moderate disease; however, evidence for 5-aminosalicylate treatment is unclear in some situations. This review discusses the clinical guidelines and previous studies, and highlights the following points: (1) Although rectal 5-aminosalicylate is effective for proctitis, physicians should endeavor to reduce patient's distress when administering suppositories or enema as the first-line therapy. It should be clarified whether oral 5-aminosalicylate alone with a drug delivery system that allows higher 5-aminosalicylate concentrations to reach the distal colon would be as effective as rectal 5-aminosalicylate therapy. (2) There has been no direct evidence demonstrating the clinical efficacy of switching the 5-aminosalicylate treatment to other 5-aminosalicylate formulations. However, switching to a different 5-aminosalicylate formulation may be indicated if clinical symptoms are not progressive. (3) Several studies have shown that colonic mucosal 5-aminosalicylate concentration correlates with clinical and endoscopic severity; however, it is unclear whether a high 5-aminosalicylate concentration has therapeutic efficacy. (4) The maximum dose of 5-aminosalicylate is necessary for patients with risk factors for recurrence or hospitalization. (5) Optimization of 5-aminosalicylate dosage may be indicated even for quiescent patients with ulcerative colitis if mucosal healing is not obtained, and if patients have multiple risk factors for recurrence. (6) Furthermore, the discontinuation of 5-aminosalicylate is acceptable when biologics are used. Because there are many "old studies" providing evidence for 5-aminosalicylate formulations, more clinical studies are needed to establish new evidence.

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.

Innovations in Oral Therapies for Inflammatory Bowel Disease

Prior to the biologic era, the medical management of patients with inflammatory bowel disease (IBD) was dominated by the use of aminosalicylates, corticosteroids, and immunosuppressants. In the past two decades, the advent of biologic agents that target specific components of the immune response has greatly improved the care of patients with Crohn's disease and ulcerative colitis (UC). However, not all patients respond or maintain response to biologic therapy and some patients develop adverse events that necessitate treatment discontinuation. Furthermore, sensitization with formation of anti-drug antibodies is an inherent limitation to administration of monoclonal antibodies. This circumstance has generated renewed interest in the development of novel oral small-molecule drugs (SMDs) that are effective and well tolerated. Several classes of SMDs are currently progressing through the pipeline and offer the promise of oral delivery and high potency. In this review, we summarize different mechanisms of oral drug delivery to the gastrointestinal tract, highlight key findings from phase II and III randomized trials of novel oral SMDs, and discuss how oral SMDs are likely to be integrated into future IBD treatment paradigms. The most advanced development programs currently involve evaluation of compounds blocking Janus kinase (JAK) receptors or modulating sphingosine-1-phosphate (S1P) receptors. Tofacitinib, an oral JAK inhibitor, was recently approved for the treatment of moderate-to-severe UC. Several more selective JAK-1 inhibitors, including filgotinib and upadacitinib, have also shown positive results in phase II studies and are currently enrolling in phase III development programs. Similarly, ozanimod, an S1P1 and S1P5 receptor agonist, has shown early favorable results and is enrolling in phase III trials. As these and other novel oral SMDs come to market, several questions will need to be answered. The cost effectiveness, comparative treatment efficacy, predictors of response, and relative safety of oral SMDs compared to existing therapies will need to be evaluated. Given the modest efficacy rates observed with both biologic therapies and novel SMDs to date, the potential for combination therapy based on a non-sensitizing oral option is promising and may be facilitated by development of organ-specific therapies with pharmacodynamic activity restricted to the gut to minimize systemic toxicity.

Mucosal 5-aminosalicylic acid concentration, drug formulation and mucosal microbiome in patients with quiescent ulcerative colitis

BACKGROUND

5-aminosalicylic acid (5-ASA) is the first-line therapy for ulcerative colitis (UC). 5-ASA acts locally in the colonic mucosa by numerous proposed mechanisms, and is metabolised by N-acetyltransferase (NAT). Large variations in mucosal 5-ASA concentrations have been reported, but the underlying mechanisms are not understood.

AIM

To study the relationship between 5-ASA concentration, 5-ASA formulation, NAT genotype and bacterial microbiome in patients with UC.

METHODS

Patients with quiescent UC, using monotherapy of Mezavant (n = 18), Asacol (n = 14) or Pentasa (n = 10), 4.0-4.8 g/day were included. 5-ASA was measured in colonic mucosal biopsies and serum by ultra-high performance liquid chromatography. NAT genotypes were determined by Sanger sequencing. Bacterial microbiome was sequenced from faeces and mucosa by 16S rRNA sequencing using Illumina Miseq.

RESULTS

Mezavant provided the highest mucosal 5-ASA levels (geometric mean 2.39 ng/mg), followed by Asacol (1.60 ng/mg, 33% lower, P = 0.50) and Pentasa (0.57 ng/mg, 76% lower, P = 0.033). Mucosal 5-ASA concentration was not associated with NAT genotype, but serum 5-ASA concentration and NAT1 genotype was associated (P = 0.044). Mucosal 5-ASA concentration was positively associated with mucosal bacterial diversity (P = 0.0005) and bacterial composition. High mucosal 5-ASA concentration was related to reduced abundance of pathogenic bacteria such as Proteobacteria, and increased abundance of several favourable bacteria such as Faecalibacterium.

CONCLUSIONS

Mucosal 5-ASA concentration is positively associated with bacterial diversity and a mucosal bacterial composition that are perceived favourable in UC. Mezavant yielded higher mucosal 5-ASA concentrations than Pentasa. 5-ASA may have beneficial effects on the mucosal microbiome, and high concentrations possibly amend dysbiosis in UC.

Influence of Pharmaceutical Formulation on the Mucosal Concentration of 5-Aminosalicylic Acid and N-Acetylmesalamine in Japanese Patients with Ulcerative Colitis

The efficacy of 5-aminosalicylic acid (5-ASA) as the first-line therapy for ulcerative colitis (UC) is determined by the extent of drug delivery to the inflamed region. Moreover, differences among the various formulations influence delivery of the drug. In this study, we examined the clinical significance of colonic mucosal concentrations of 5-ASA and N-acetylmesalamine (Ac-5-ASA) in UC patients receiving a pH-dependent or time-dependent release formulation of 5-ASA. The subjects were 67 patients with UC who were treated with a pH-dependent or time-dependent formulation of 5-ASA between December 2011 and April 2014. A retrospective observational analysis of clinical outcomes was performed using the clinical activity index (CAI) obtained on the day of biopsy. Colonic mucosal concentrations of 5-ASA and Ac-5-ASA in biopsy samples were measured by LC-tandem mass spectrometry/mass spectrometry. Patients who were treated with the pH-dependent formulation had higher colon mucosal concentrations of 5-ASA than those who were treated with the time-dependent formulation. Additionally, 5-ASA concentration was significantly higher in patients with CAI scores ≤3. A higher concentration of Ac-5-ASA was achieved with the time-dependent formulation than with the pH-dependent formulation. Furthermore, patients with CAI scores ≤3 had higher concentrations of 5-ASA than those with CAI scores ≥4. The colonic mucosal concentration of 5-ASA in patients with UC is influenced by the pharmaceutical formulation and the remission status of UC.

5-Aminosalicylic acid downregulates the growth and virulence of Escherichia coli associated with IBD and colorectal cancer, and upregulates host anti-inflammatory activity

5-aminosalicylate (5-ASA) is widely prescribed for the treatment of inflammatory bowel disease (IBD) and prevention of inflammation-associated colorectal cancer (CRC). Its clinical effect is widely attributed to modulation of host inflammatory responses. However, the recent association of intestinal dysbiosis and selective enrichment in Escherichia coli in patients with IBD and CRC raises the possibility that 5-ASA might also affect the enteric microflora. The aim of this study was to investigate the effect of 5-ASA on the growth and virulence of E. coli associated with IBD and CRC, and its impact on host cell inflammatory responses. Our results show that 5-ASA inhibited E. coli growth in a dose-dependent manner and downregulated the expression of bacterial virulence genes associated with IBD (fliC, fimH, ompC, yfgL, nlpL, lpfA, htrA, dsbA, fyuA, and chuA) and CRC (pks). 5-ASA inhibited E. coli motility (30-70%), epithelial adherence and invasion, and IL-8 secretion (p < 0.05). 5-ASA reduced E. coli survival in J774A.1 macrophages by 20 to 50% (p < 0.01) and TNF-α secretion by infected macrophages up to 30% (p < 0.05). In addition, 5-ASA reduced DNA damage in epithelial cells (Caco-2) induced by pks-positive E. coli. Our results reveal a multifaceted and previously unrecognized effect of 5-ASA on the growth and virulence of IBD- and CRC-associated E. coli, in addition to its inhibitory effect on host cell inflammatory responses. These results suggest that 5-ASA may abrogate the proinflammatory and oncogenic effects of E. coli in patients with IBD and CRC.

Comparison of efficacy of once daily multimatrix mesalazine 2.4 g/day and 4.8 g/day with other 5-aminosalicylic acid preparation in active ulcerative colitis: a randomized, double-blind study

Background/Aims

This study compared the efficacy of multimatrix mesalazine 2.4 g/day and 4.8 g/day with controlled-release mesalazine 2.25 g/day.

Methods

In this multicenter, randomized, double-blind study, 251 patients with mildly to moderately active ulcerative colitis received multimatrix mesalazine 2.4 g/day once daily (Multimatrix-2.4), 4.8 g/day once daily (Multimatrix-4.8), or controlled-release (time-dependent) mesalazine 2.25 g/day 3 times daily (Time-2.25) for 8 weeks. The primary efficacy endpoint was the change in the ulcerative colitis-disease activity index (UC-DAI) score.

Results

The mean change in the UC-DAI score and standard deviation in the per protocol set was -1.9±2.5 for Multimatrix-2.4 and -2.4±2.8 for Time-2.25. The difference between Multimatrix-2.4 and Time-2.25 was 0.3 (two-sided 95% confidence interval [CI], -0.5 to 1.1), thus non-inferiority was not demonstrated based on the pre-defined non-inferiority margin (1.0). In the full analysis set, the difference between Multimatrix-4.8 and Time-2.25 was -1.2 (two-sided 95% CI, -2.0 to -0.5), and the mean change in UC-DAI score in the FAS was -3.3 (two-sided 95% CI, -3.9 to -2.8) for Multimatrix-4.8 and -1.9 (two-sided 95% CI, -2.5 to -1.3) for Multimatrix-2.4, indicating that Multimatrix-4.8 was more effective than Time-2.25 and Multimatrix-2.4. There was no difference among the treatment groups in terms of safety.

Conclusions

This study showed that the efficacy of multimatrix mesalazine 2.4 g/day was comparable to controlled release mesalazine 2.25 g/day, although non-inferiority was not demonstrated. Importantly, this was the first study to indicate that multimatrix mesalazine 4.8 g/day was more effective than 2.4g/day with no associated safety concerns.

Urinalysis of MMX-mesalazine as a tool to monitor 5-ASA adherence in daily IBD practice

Adherence is pivotal but challenging in ulcerative colitis (UC) treatment. Many methods to assess adherence are subjective or have limitations. (Nac-)5-aminosalicylic acid (5-ASA) urinalysis by high-performance liquid chromatography (HPLC) seems feasible and reproducible in healthy volunteers. We performed a prospective study in adult quiescent UC patients to evaluate the feasibility of spot (Nac-)5-ASA urinalysis by HPLC to assess adherence in daily inflammatory bowel disease (IBD) care. Twenty-nine patients (51.7% male, mean age 52 ± 11 years) were included (median FU 9 months) and weekly spot urine samples were collected. We found large variation in spot (Nac-)5-ASA urinary excretion that was unrelated to brand, dosing schedule or dosage of 5-ASA. In conclusion, spot (Nac-)5-ASA urinalysis is not applicable to assess 5-ASA adherence in daily IBD care.

Nanoparticulate Drug Delivery Systems Targeting Inflammation for Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, idiopathic inflammatory set of conditions that can affect the entire gastrointestinal (GI) tract and is associated with an increased risk of colorectal cancer. To date there is no curative therapy for IBD; therefore life-long medication can be necessary for IBD management if surgery is to be avoided. Drug delivery systems specific to the colon have improved IBD treatment and several such systems are available to patients. However, current delivery systems for IBD do not target drugs to the site of inflammation, which leads to frequent dosing and potentially severe side effects that can adversely impact patients' adherence to medication. There is a need for novel drug delivery systems that can target drugs to the site of inflammation, prolong local drug availability, improve therapeutic efficacy, and reduce drug side effects. Nanoparticulate (NP) systems are attractive in designing targeted drug delivery systems for the treatment of IBD because of their unique physicochemical properties and capability of targeting the site of disease. This review analyzes the microenvironment at the site of inflammation in IBD, highlighting the pathophysiological features as possible cues for targeted delivery; discusses different strategies and mechanisms of NP targeting IBD, including size-, charge-, ligand-receptor, degradation- and microbiome-mediated approaches; and summarizes recent progress on using NPs towards improved therapies for IBD. Finally, challenges and future directions in this field are presented to advance the development of targeted drug delivery for IBD treatment.

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.

Comparison of efficacy of multimatrix mesalazine 4.8 g/day once-daily with other high-dose mesalazine in active ulcerative colitis: a randomized, double-blind study

Background/Aims

This study assessed the efficacy and safety of high-dose multimatrix mesalazine once-daily (QD) compared to another form of high-dose mesalazine.

Methods

In this multicenter, randomized, double-blind study, 280 patients with mildly to moderately active ulcerative colitis (UC) received multimatrix mesalazine 4.8 g/day QD or pH-dependent-release mesalazine 3.6 g/day three times daily for 8 weeks. The primary endpoint was the change in the UC-Disease Activity Index (UC-DAI) at the end of the treatment period.

Results

The change in the UC-DAI (mean±standard deviation) in the per-protocol set was −2.6±2.47 in the multimatrix mesalazine 4.8 g/day group (n=134) and −1.8±2.64 in the pH-dependent-release mesalazine 3.6 g/day group (n=129). The difference in the mean change between the 2 groups was −0.7 (two-sided 95% confidence interval, −1.3 to −0.1). The noninferiority of multimatrix mesalazine 4.8 g/day to pH-dependent-release mesalazine 3.6 g/day was verified within the noninferiority margin (1.1). The superiority of multimatrix mesalazine 4.8 g/day to pH-dependent-release mesalazine 3.6 g/day was also investigated and confirmed in the full analysis set, according to the study protocol. In subgroup analyses, the effectiveness of multimatrix mesalazine 4.8 g/day was consistent in all subgroups. There was no difference in safety between the 2 treatment groups.

Conclusions

Multimatrix mesalazine 4.8 g/day has higher efficacy and shows no difference in safety in mildly to moderately active UC, in comparison with pH-dependent-release mesalazine 3.6 g/day.

Usefulness of sulfasalazine for patients with refractory-ulcerative colits

BACKGROUND

Patients with refractory-ulcerative colitis (UC) require therapy escalation. Sulfasalazine (SASP) could deliver a high concentration of 5-aminosalicylic acid to the colon. The usefulness of SASP for refractory-UC patients, however, is unclear.

AIM

The aim was to evaluate the usefulness of SASP for refractory-UC patients.

METHOD

We retrospectively analysed 36 (11.4%) of 316 patients with refractory-UC who had been treated with SASP. Clinical and endoscopic activities were evaluated with Lichtiger index and Mayo score, respectively. We analysed the induction-remission rate, predictive factors for the efficacy of SASP, and adverse events.

RESULTS

Of 36 refractory-UC patients, 14 (38.9%) were treated with concomitant mesalazine enemas, 10 (27.8%) with azathiopurine, 4 (11.1%) with tacrolimus and 6 (16.7%) with an antitumour necrosis factor-α agent. After initiating SASP treatment, 25 patients (69.4%) achieved clinical remission. In 9 (64.3%) of 14 patients with UC treated with mesalazine enemas, mesalazine enemas could be discontinued with SASP. In all patients treated with tacrolimus, tacrolimus could be discontinued with SASP. Clinical activity score upon the initiation of SASP was significantly lower (p=0.024) and the number of patients treated with thiopurine was significantly higher (p=0.016) in the clinical remission group than in the non-clinical remission group. These factors might be predictive for the efficacy of SASP, although multivariate analysis demonstrated no statistically significant effect. Adverse events occurred in 7 patients (19.4%), and reduction or discontinuation of SASP led to improvement.

CONCLUSIONS

SASP appears to be more effective for refractory-UC patients with low clinical-activity and/or thiopurine-use.

TRIAL REGISTRATION NUMBER

UMIN000021615; Results.

Ultrasound-mediated gastrointestinal drug delivery

There is a significant clinical need for rapid and efficient delivery of drugs directly to the site of diseased tissues for the treatment of gastrointestinal (GI) pathologies, in particular, Crohn's and ulcerative colitis. However, complex therapeutic molecules cannot easily be delivered through the GI tract because of physiologic and structural barriers. We report the use of ultrasound as a modality for enhanced drug delivery to the GI tract, with an emphasis on rectal delivery. Ultrasound increased the absorption of model therapeutics inulin, hydrocortisone, and mesalamine two- to tenfold in ex vivo tissue, depending on location in the GI tract. In pigs, ultrasound induced transient cavitation with negligible heating, leading to an order of magnitude enhancement in the delivery of mesalamine, as well as successful systemic delivery of a macromolecule, insulin, with the expected hypoglycemic response. In a rodent model of chemically induced acute colitis, the addition of ultrasound to a daily mesalamine enema (compared to enema alone) resulted in superior clinical and histological scores of disease activity. In both animal models, ultrasound treatment was well tolerated and resulted in minimal tissue disruption, and in mice, there was no significant effect on histology, fecal score, or tissue inflammatory cytokine levels. The use of ultrasound to enhance GI drug delivery is safe in animals and could augment the efficacy of GI therapies and broaden the scope of agents that could be delivered locally and systemically through the GI tract for chronic conditions such as inflammatory bowel disease.

Medical Therapy of Active Ulcerative Colitis

Background

Medical therapy of mild and moderate ulcerative colitis (UC) of any extent is evidence-based and standardized by national and international guidelines. However, patients with steroid-refractory UC still represent a challenge.

Methods

A literature search using PubMed (search terms: ulcerative colitis, therapy, new, 1-2008-2015) resulted in 821 publications. For the current article, 88 citations were extracted including 36 randomized controlled studies, 18 reviews, and 8 meta-analyses.

Results

In steroid-refractory UC, early intensive therapy using anti-tumor necrosis factor (TNF) antibodies or the calcineurin inhibitors cyclosporine and tacrolimus is indicated in any case to prevent progression to a toxic megacolon and/or to avoid proctocolectomy. In patients with chronic disease activity, treatment with anti-TNF antibodies has a higher level of evidence than azathioprine therapy and should therefore be preferred. However, there is a subgroup of UC patients who may achieve prolonged steroid-free remission on azathioprine monotherapy. The importance of vedolizumab, a newly registered inhibiting antibody against integrin, has not yet been fully clarified since direct comparison studies are lacking, in particular in relation to anti-TNF antibodies.

Conclusion

There is a great need for additional innovative therapies, especially in cases of primary non-response or secondary loss of response to anti-TNF antibodies. New small molecules (Janus kinase inhibitors) are promising with an acceptable safety profile and efficacy in UC. Further, strategies that target the intestinal microbiome are currently considered for patients with active or relapsing UC, and may in the future open up new therapeutic options.

Review article: The pharmacokinetics and pharmacodynamics of drugs used in inflammatory bowel disease treatment

BACKGROUND

The following review is a compilation of the recent advances and knowledge on the behaviour of the most frequently used compounds to treat inflammatory bowel disease in an organism.

RESULTS

It considers clinical aspects of each entity and the pharmacokinetic/pharmacodynamic relationship supported by the use of plasma monitoring, tissue concentrations, and certain aspects derived from pharmacogenetics.

Curcumin-piperine mixtures in self-microemulsifying drug delivery system for ulcerative colitis therapy

Curcumin (CUR) is a poorly water-soluble drug and its absorption is very low. In this study, CUR and piperine (PIP) were co-encapsulated into the nanoformulation called self-microemulsifying drug delivery system (SMEDDS) to improve the stability and water-solubility of CUR and enhance its anti-colitis activity. The formulation of CUR-PIP-SMEDDS was prepared to encapsulate two hydrophobic components CUR and PIP, and then was characterized by assessing appearance, morphology, particle size, zeta potential and drug encapsulation efficiency. The appearance of CUR-PIP-SMEDDS remained clarified and transparent, and the microemulsion droplets appeared spherical without aggregation. The mean size of microemulsion droplet formed from CUR-PIP-SMEDDS was 15.87 ± 0.76 nm, and the drug encapsulation efficiency of SMEDDS for CUR and PIP were (94.34 ± 2.18)% and (90.78 ± 2.56)%, respectively. The vitro stability investigation of CUR-PIP-SMEDDS in colon tissue suggested that using SMEDDS as a delivery vehicle and co-encapsulated with PIP, CUR was more stable than drug solution in colons site. Meanwhile, the anti-inflammatory activity of CUR-PIP-SMEDDS was evaluated on DSS-induced colitis model. The results showed that CUR-PIP-SMEDDS exhibited definite anti-colitis activity by directing CUR-PIP-SMEDDS to inflammatory colon tissue through retention enema administration. Our study illustrated that the developed CUR-PIP-SMEDDS formulation was a potential carrier for developing colon-specific drug delivery system of CUR for ulcerative colitis treatment.

Dissolution of mesalazine modified release tablets under standard and bio-relevant test conditions

OBJECTIVES

For the treatment of inflammatory bowel disease, the development of pH responsive modified release dosage forms is one of the most common approaches to achieve targeted drug delivery. In this study, the dissolution behaviour of eight different modified release (MR) products containing 800 mg mesalazine was investigated.

METHODS

The performance of the products was compared under simulated fasted state conditions using the paddle apparatus as well as the dissolution stress test device mimicking mechanical stress events of bio-relevant intensity.

KEY FINDINGS

The dissolution behaviour of the eight tested different pH-responsive MR tablets containing 800 mg mesalazine was dependent on the test conditions. Phases of mechanical stress with physiological intensity influenced the dissolution characteristics and caused in some cases accelerated drug release indicating possible dose dumping.

CONCLUSION

The study demonstrates that besides the investigation of the pH dependency of drug release, the characterisation of the mechanical robustness of the dosage forms is an essential factor determining the dissolution characteristics of such pH-dependent targeted modified release tablets. The susceptibility of 800 mg mesalazine MR tablets towards mechanical stress may be one reason for undesired drug delivery in vivo.

The immunologic effects of mesalamine in treated HIV-infected individuals with incomplete CD4+ T cell recovery: a randomized crossover trial

The anti-inflammatory agent, mesalamine (5-aminosalicylic acid) has been shown to decrease mucosal inflammation in ulcerative colitis. The effect of mesalamine in HIV-infected individuals, who exhibit abnormal mucosal immune activation and microbial translocation (MT), has not been established in a placebo-controlled trial. We randomized 33 HIV-infected subjects with CD4 counts <350 cells/mm3 and plasma HIV RNA levels <40 copies/ml on antiretroviral therapy (ART) to add mesalamine vs. placebo to their existing regimen for 12 weeks followed by a 12 week crossover to the other arm. Compared to placebo-treated subjects, mesalamine-treated subjects did not experience any significant change in the percent CD38+HLA-DR+ peripheral blood CD4+ and CD8+ T cells at week 12 (P = 0.38 and P = 0.63, respectively), or in the CD4+ T cell count at week 12 (P = 0.83). The percent CD38+HLA-DR+ CD4+ and CD8+ T cells also did not change significantly in rectal tissue (P = 0.86, P = 0.84, respectively). During the period of mesalamine administration, plasma sCD14, IL-6, D-dimer, and kynurenine to tryptophan ratio were not changed significantly at week 12 and were similarly unchanged at week 24. This study suggests that, at least under the conditions studied, the persistent immune activation associated with HIV infection is not impacted by the anti-inflammatory effects of mesalamine.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01090102.

Accuracy of Rapid Fecal Calprotectin Test in Monitoring Inflammatory Bowel Diseases Under Treatment with TNFα Antagonists

BACKGROUND

Anti-TNFα antibodies are effective in treating inflammatory bowel diseases (IBDs) unresponsive to the standard treatments. Information about the role of rapid fecal calprotectin (FC) in monitoring ambulatory IBD patients under treatment with anti-TNFα is lacking. Our aim was to assess the accuracy of rapid FC in monitoring those patients.

METHODS

Seventy-two patients (38 males, 34 females, mean age 42.5 years, range 23-57 years), affected by ulcerative colitis (UC) (20 patients) or by Crohn's disease (CD) (52 patients) were treated with anti-TNFα antibodies. FC was assessed by a rapid semiquantitative test.

RESULTS

With respect to the absence of clinical remission, FC test showed sensitivity of 71.8 %, specificity of 65.2 %, PPV of 41.8 %, and NPV of 86.9 %. In UC patients, FC test showed a sensitivity of 66.7 %, a specificity of 56.1 %, a PPV of 18.2 %, and a NPV of 92.0 %. In CD patients, FC test showed sensitivity of 70.6 %, specificity of 65.2 %, PPV of 50.0 %, and NPV of 81.8 %. With respect to the presence of endoscopic lesions, FC test showed sensitivity of 73.5 %, specificity of 96.0 %, PPV of 96.2 %, and NPV of 72.7 %. In UC patients, FC test showed sensitivity of 47.2 %, specificity of 84.6 %, PPV of 89.5 %, and NPV of 36.7 %. In CD patients, FC test showed sensitivity of 90.1 %, specificity of 79.7 %, PPV of 71.9 %, and NPV of 93.3 %.

CONCLUSIONS

Diagnostic accuracy of rapid FC seems better in predicting persistence of endoscopic lesions than clinical remission in IBD patients under treatment with anti-TNFα.

Nanotechnology in the treatment of inflammatory bowel diseases

BACKGROUND AND AIMS

Treatment of inflammatory bowel diseases (IBD) is only aimed to block or inhibit the pathogenetic steps of the inflammatory cascade. Side effects of systemic therapies, poor targeting of orally administered topical drug and low adherence to prescription represent frequent therapeutic challenges. Recent observations suggest that nanotechnology could provide amazing advantage in this field since particles having dimension in the nanometer scale (nanoparticles) can modify pharmacokinetic step of biologic and conventional therapeutic agents with a better delivery of drugs within the intestinal inflammatory cells. The aim of this review was to provide the clinician with an insight into the potential role of nanotechnology in the treatment of IBD.

METHODS

A systematic search (PubMed) for experimental studies on the treatment of intestinal inflammation using nanotechnology for the delivery of drugs.

RESULTS AND CONCLUSIONS

The size of the pharmaceutical formulation is inversely related to specificity for inflammation. Nanoparticles can penetrate epithelial and inflammatory cells resulting in much higher, effective and long-acting concentrations than can be obtained using conventional delivery systems. From a practical point of view, this should lead to improvements in both efficacy and adherence to treatment, providing patients with the prospect of stable and prolonged remissions with reduced drug loadings. Reduced systemic side effects could also be expected.

Effectiveness of a hydroxynaphthoquinone fraction from Arnebia euchroma in rats with experimental colitis

AIM: To evaluate the potential effectiveness of hydroxynaphthoquinone mixture (HM) in rats with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis.

METHODS: Colitis was induced by intracolonic administration of TNBS (80 mg/kg, dissolved in 50% ethanol). Rats were treated daily for 7 d with HM (2.5, 5, 10 mg/kg) and mesalazine 100 mg/kg 24 h after TNBS instillation. Disease progression was monitored daily by observation of clinical signs and body weight change. At the end of the experiment, macroscopic and histopathologic lesions of rats were scored, and myeloperoxidase (MPO) activity was determined. We also determined inflammatory cytokine tumor necrosis factor (TNF)-α level by ELISA, Western blotting and immunochemistry to explore the potential mechanisms of HM.

RESULTS: After intracolonic instillation of TNBS, animals developed colitis associated with soft stool, diarrhea and marked colonic destruction. Administration of HM significantly attenuated clinical and histopathologic severity of TNBS-induced colitis in a dose-dependent manner. It abrogated body weight loss, diarrhea and inflammation, decreased macroscopic damage score, and improved histological signs, with a significant reduction of inflammatory infiltration, ulcer size and the severity of goblet cell depletion (all P < 0.05 vs TNBS alone group). HM could reduce MPO activity. In addition, it also decreased serum TNF-α level and down-regulated TNF-α expression in colonic tissue. This reduction was statistically significant when the dose of HM was 10 mg/kg (P < 0.05 vs TNBS alone group), and the effect was comparable to that of mesalazine and showed no apparent adverse effect. The underlying mechanism may be associated with TNF-α inhibition.

CONCLUSION: These findings suggest that HM possesses favourable therapeutic action in TNBS-induced colitis, which provides direct pharmacological evidence for its clinical application.

5-ASA colonic mucosal concentrations resulting from different pharmaceutical formulations in ulcerative colitis

AIM: To compare the mucosal concentrations of 5-aminosalicylic acid (5-ASA) resulting from different pharmaceutical formulations and analyse the influence of inflammation on the mucosal concentrations.

METHODS: The study included 130 inflammatory bowel disease (IBD) patients receiving 5-ASA as pH-dependent-release formulations (73 patients), time-dependent-release formulations (11 patients), or pro-drugs (18 patients). In addition, 28 patients were receiving topical treatment (2-4 g/d) with pH-dependent-release formulations. Endoscopic biopsies were obtained from the sigmoid region during the colonoscopy. The 5-ASA concentrations (ng/mg) were measured in tissue homogenates using high-pressure liquid chromatography with electrochemical detection. The t test and Mann-Whitney test, when appropriate, were used for statistical analysis.

RESULTS: Patients receiving pH-dependent-release formulations showed significantly higher mucosal concentrations of 5-ASA (51.75 ± 5.72 ng/mg) compared with patients receiving pro-drugs (33.35 ± 5.78 ng/mg, P = 0.01) or time-dependent-release formulations (38.24 ± 5.53 ng/mg, P = 0.04). Patients with endoscopic remission had significantly higher mucosal concentrations of 5-ASA than patients with active disease (60.14 ± 7.95 ng/mg vs 35.66 ± 5.68 ng/mg, P = 0.02). Similar results were obtained when we compared patients with the histological appearance of remission and patients with active histological inflammation (67.53 ± 9.22 ng/mg vs 35.53 ± 5.63 ng/mg, P < 0.001). Significantly higher mucosal concentrations of 5-ASA were detected in patients treated with both oral and topical treatments in combination compared with patients who received oral treatment with pH-dependent-release formulations alone (72.33 ± 11.23 ng/mg vs 51.75 ± 5.72 ng/mg, P = 0.03).

CONCLUSION: IBD patients showed significant variability in mucosal 5-ASA concentrations depending on the type of formulation, and the highest mean concentration was achieved using pH-dependent-release formulations.

New targeting strategies in drug therapy of inflammatory bowel disease: mechanistic approaches and opportunities

INTRODUCTION

Inflammatory bowel disease (IBD) is an exceptional scenario with regard to drug targeting, as oral administration has the potential to deliver the drug directly to the site(s) of action. Consequently, retention of the drug within the intestinal lumen and tissue, rather than systemic absorption, is frequently desirable.

AREAS COVERED

In this article, the traditional drug-delivery strategies used in IBD are briefly summarized. These include rectal dosage forms and oral systems that target the lower intestine/colon by pH-, time-, microflora-, and pressure-dependent mechanisms. Then, the article offers an updated overview of recently developed delivery systems aimed to achieve maximal drug concentrations in the inflamed intestinal tissues with minimal systemic side effects. These include antibodies, small molecules, Janus kinase inhibitors, particulate carrier systems, anti-inflammatory peptides, gene therapy, and transgenic bacteria. The various approaches are reviewed, and the challenges that still remain to be overcome are discussed.

EXPERT OPINION

The molecular revolution of the past decade profoundly influenced the treatment and management of IBD. In the coming years, this trend is expected to continue. Yet, many challenges are still ahead. A strong collaborative effort by experts from different fields is encouraged and necessary to maximize our success in IBD drug targeting.

Refractory distal ulcerative colitis: Clinical manifestations and treatment

AIM: To investigate the clinical features and treatment of distal ulcerative colitis (DUC) and to analyze probable reasons and optimal therapeutic regimens for refractory DUC.

METHODS: Clinical data for 145 DUC patients who were treated at the Affiliated Yijishan Hospital of Wannan Medical College from January 2005 to December 2011 were retrospectively analyzed. Based on the response to traditional treatments, the patients were divided into either an effective group or a refractory group. The two groups were compared in clinical and laboratory examination results to analyze probable reasons and optimal therapeutic regimens for refractory DUC.

RESULTS: Of 145 DUC patients, 117 were eligible for evaluation, and 26 of 117 patients were confirmed to have refractory DUC. The percentages of patients with abdominal distention and abdominal pain or elevated white blood cell count differed significantly between the refractory group and effective group (42.3% vs 22.0%, P = 0.038; 30.8% vs 12.1%, P = 0.035), while no significant differences were found in bloody stools, diarrhea, extraintestinal manifestations, C-reactive protein, blood sedimentation between the two groups (all P > 0.05). Of all 117 cases, 43 were found to have rectitis (including 10 refractory cases), and 74 were found to have sigmoiditis (including 16 refractory cases). No significant difference was found between the two groups in the location of the lesions (P > 0.05). Of 26 refractory cases, only 1 was treated by surgery, and the others were treated by intravenous hormone therapy, addition of new dosage form of 5-ASA, or proper laxatives to gain relief.

CONCLUSION: Diarrhea and bloody stools are the most common clinical symptoms of DUC. Significantly elevated leukocyte count can be expected to be an important factor for evaluating treatment outcome of DUC. Refractory DUC can be treated by intensification therapy, addition of new dosage form of 5-ASA, proper laxatives, or surgery to gain relief.

Simulated comparison of topical and oral formulations of 5-aminosalicylate for the treatment of ulcerative colitis

BACKGROUND

5-Aminosalicylate (5-ASA) formulations are approved for the treatment of ulcerative colitis (UC). Determination of the colonic pharmacokinetics of 5-ASA is challenging. A dynamic model of 5-ASA colonic amounts after oral delayed-release 5-ASA (Asacol), oral extended delayed-release 5-ASA (Lialda), 5-ASA enema (Rowasa), foam and suppositories (Canasa) was developed to determine the colonic kinetics of these agents.

METHODS

We created a model with Stella software. Colonic 5-ASA in the right, transverse, descending, sigmoid colon, and rectum were estimated for adults after recommended doses of the above formulations. Simulations of active mild/moderate UC and in remission were performed and compared using Student's t-test for differences in means.

RESULTS

For UC in remission, the highest amounts of 5-ASA were from Asacol in the right and transverse colon (P < 0.01), Lialda in the descending and sigmoid colon (P < 0.01), and Rowasa in the rectum (P < 0.01). For active UC, sigmoid amounts were highest with foam (P < 0.01), and rectal amounts highest with Rowasa (P < 0.01). Differences in rectosigmoid amounts of 5-ASA from enemas and suppositories for UC in remission occurred based on the relationship between the timing of administration relative to the daily bowel movement (P < 0.01).

CONCLUSIONS

Compared to Asacol, Lialda results in higher 5-ASA amounts in the left colon. Asacol with Rowasa provides highest 5-ASA amounts across the entire colon. Higher 5-ASA amounts from topical formulations occur when the insertion occurs soon after the daily bowel movement. This model provides a rationale for further investigation.

[Guidelines for the management of ulcerative colitis]

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by a relapsing and remitting course. The quality of life can decreases significantly during exacerbations of the disease. The incidence and prevalence of UC in Korea are still lower than those of Western countries, but have been rapidly increasing during the past decades. Various medical and surgical therapies are currently used for the management of UC. However, many challenging issues exist and sometimes these lead to differences in practice between clinicians. Therefore, Inflammatory Bowel Diseases (IBD) Study Group of Korean Association for the Study of Intestinal Diseases (KASID) set out the Korean guidelines for the management of UC. These guidelines are made by the adaptation using several foreign guidelines and encompass treatment of active colitis, maintenance of remission and indication for surgery in UC. The specific recommendations are presented with the quality of evidence. These are the first Korean treatment guidelines for UC and will be revised with new evidences on treatment of UC.

Review article: delivery and efficacy of topical 5-aminosalicylic acid (mesalazine) therapy in the treatment of ulcerative colitis

BACKGROUND

The use of topical therapy in the treatment of ulcerative colitis has declined in recent years despite evidence of good efficacy.

AIMS

To review US prescription trends for 5-aminosalicylic acid (5-ASA) since the US approval of Asacol extended-release oral mesalazine (mesalamine) in 1992; to estimate the optimal level of 5-ASA exposure in the distal colon; to determine factors influencing distal colonic exposures; and to compare the effectiveness of different 5-ASA formulations (oral, topical suspension, foam, suppositories) in clinical trials.

METHODS

Review of clinical trials, physiologic studies and prescription trends of various mesalazine formulations for treatment of distal ulcerative colitis.

RESULTS

Between 1992 and 2009, prescriptions for oral mesalazine increased sixfold, whereas topical suspensions declined by 10%. In clinical trials, topical therapy resulted in higher remission and clinical response rates than oral therapy, with trends to earlier improvement. The mucosal concentrations of 5-ASA achieved by topical agents in the distal colon were up to 200-fold higher than those achieved by oral administration alone. Despite active colitis, over 40% of a topically administered 4 g 5-ASA suspension (equal to 1.6 g) reached the sigmoid colon. This likely represents a therapeutic exposure of 5-ASA. Although topical therapies are less convenient than oral medications, treatment algorithms have failed to take into account quality of life improvements resulting from more rapid and complete treatment response.

CONCLUSIONS

Topical mesalazine therapy is superior to oral therapy in distal ulcerative colitis for both therapeutic response and drug delivery. Practice patterns should be re-evaluated in light of this information.

Role of organic anion-transporting polypeptides for cellular mesalazine (5-aminosalicylic acid) uptake

The therapeutic effects and metabolism of mesalazine (5-aminosalicylic acid) in patients with inflammatory bowel disease require intracellular accumulation of the drug in intestinal epithelial cells and hepatocytes. The molecular mechanisms of mesalazine uptake into cells have not been characterized so far. Using human embryonic kidney cells stably expressing uptake transporters of the organic anion-transporting polypeptide (OATP) family, which are expressed in human intestine and/or liver, we found that mesalazine uptake is mediated by OATP1B1, OATP1B3, and OATP2B1 but not by OATP1A2 and OATP4A1. Moreover, genetic variations (*1b, *5, *15) in the SLCO1B1 gene encoding OATP1B1 reduced the K(m) value for mesalazine uptake from 55.1 to 16.3, 24.3, and 32.4 μM, respectively, and the respective V(max) values. Finally, budesonide, cyclosporine, and rifampin were identified as inhibitors of OATP1B1-, OATP1B3-, and OATP2B1-meditated mesalazine uptake. These in vitro data indicate that OATP-mediated uptake and its modification by genetic factors and comedications may play a role for mesalazine effects.