Use of new once-daily 5-aminosalicylic acid preparations in the treatment of ulcerative colitis: Is there anything new under the sun?

Drug Disposition in the Lower Gastrointestinal Tract: Targeting and Monitoring

The increasing prevalence of colonic diseases calls for a better understanding of the various colonic drug absorption barriers of colon-targeted formulations, and for reliable in vitro tools that accurately predict local drug disposition. In vivo relevant incubation conditions have been shown to better capture the composition of the limited colonic fluid and have resulted in relevant degradation and dissolution kinetics of drugs and formulations. Furthermore, drug hurdles such as efflux transporters and metabolising enzymes, and the presence of mucus and microbiome are slowly integrated into drug stability- and permeation assays. Traditionally, the well characterized Caco-2 cell line and the Ussing chamber technique are used to assess the absorption characteristics of small drug molecules. Recently, various stem cell-derived intestinal systems have emerged, closely mimicking epithelial physiology. Models that can assess microbiome-mediated drug metabolism or enable coculturing of gut microbiome with epithelial cells are also increasingly explored. Here we provide a comprehensive overview of the colonic physiology in relation to drug absorption, and review colon-targeting formulation strategies and in vitro tools to characterize colonic drug disposition.

Switching between Three Types of Mesalazine Formulation and Sulfasalazine in Patients with Active Ulcerative Colitis Who Have Already Received High-Dose Treatment with These Agents

BACKGROUND AND AIM

Oral mesalazine and sulfasalazine (SASP) are key drugs for treating ulcerative colitis (UC). The efficacy of switching from one of the several mesalazine formulations to another is largely unknown. This study assessed the efficacy of switching among three types of mesalazine formulation and SASP for UC therapy.

METHODS

UC patients receiving high-dose mesalazine/SASP who switched to other formulations due to disease activity were considered eligible. Efficacy was evaluated 2, 6, and 12 months after switching.

RESULTS

A total of 106 switches in 88 UC patients were analyzed. The efficacy at 2 months after switching was observed in 23/39 (59%) cases from any mesalazine formulation to SASP, in 18/55 (33%) cases from one mesalazine to another, and in 2/12 (17%) cases from SASP to any mesalazine formulation. Nine of 43 effective cases showed inefficacy or became intolerant post-switching. Delayed efficacy more than two months after switching was observed in four cases. Steroid-free remission was achieved in 42/106 (39%) cases-within 100 days in 35 of these cases (83%).

CONCLUSIONS

Switching from mesalazine to SASP was effective in more than half of cases. The efficacy of switching between mesalazine formulations was lower but may be worth attempting in clinical practice from a safety perspective.

Mesalazine preparations for the treatment of ulcerative colitis: Are all created equal?

Oral mesalazine (also known as mesalamine) is a 5-aminosalicylic acid compound used in the treatment of mild to moderate ulcerative colitis, with high rates of efficacy in induction and maintenance of remission. The therapeutic effect of mesalazine occurs topically at the site of diseased colonic mucosa. A myriad of oral mesalazine preparations have been formulated with various drug delivery methods to minimize systemic absorption and maximise drug availability at the inflamed colonic epithelium. It remains unclear whether different oral mesalazine formulations are bioequivalent. This review aims to evaluate the differences between mesalazine formulations based on the currently available literature and explore factors which may influence the selection of one agent above another.

Long-term efficacy and safety of once-daily mesalazine granules for the treatment of active ulcerative colitis

In 1977, 5-aminosalicylic acid (5-ASA) was discovered as a therapeutically active moiety of sulfasalazine (SASP) and was launched for topical and oral therapy of ulcerative colitis (UC) in 1984. As a first-step, delivery systems had to be developed to protect 5-ASA against absorption in the upper gastrointestinal tract, resulting in different and competing strategies (azo compounds, controlled release, and pH-dependent release). In a second step, at the beginning of the new century, coinciding with the expiration of patent protection for the first 5-ASA formulations, two component composite release mechanisms (pH-dependent and controlled release) were developed. Furthermore, the drug was formulated as granules instead of tablets, allowing higher unit strengths compared with tablets. Neither Salofalk Granu-Stix^®, nor MMX 5-ASA, nor Pentasa^® granules have initially been developed for once-daily (OD) dosing. A review of the achievements of 20 years of 5-ASA development has demonstrated that 5-ASA has equal efficacy compared with SASP at best, that there are no measurable differences in efficacy between various 5-ASA preparations, and that in a group of patients tolerating SASP, adverse event profiles of SASP and 5-ASA did not differ significantly, with SASP being the far cheaper substance. Therefore, drug adherence came into focus as a new goal for improving UC therapy. Although adherence is a complex and multifactorial construct, a simple dosing schedule may contribute to higher drug adherence and better efficacy of treatment. Simultaneously, the US 5-ASA market, estimated to be worth US$1.4 billion, is expected to grow continuously. Naturally, this very competitive market is not only driven by scientific progress but also by commercial interests. Thus, patents for minor changes to the formulation may serve as protection against drug companies trying to launch generic versions. Randomized controlled trials performed on OD dosing in induction of remission have demonstrated that OD administration of 5-ASA is as effective as conventional dosing in mild to moderate active UC. The three 5-ASA products MMX, Salofalk^®, and Pentasa^® employed in those studies so far have not shown differences in efficacy between OD and conventional dosing. No differences regarding safety outcomes have been detected between OD and conventional dosing, including incidence of adverse events, serious adverse events, or withdrawal from treatment due to an adverse event. Although the majority of patients prefer OD dosing to conventional dosing, it was not possible to detect differences in adherence between OD and multiple dose regimens in the clinical trial setting. Well-designed and controlled large-scale community-based studies are necessary to further investigate and prove the point of improved long-term adherence and treatment efficacy in OD dosing.

Tacrolimus effects and side effects after liver transplantation: is there a difference between immediate and extended release?

BACKGROUND

Immunosuppressive therapy after orthotopic liver transplantation (OLT) requires a high degree of patient compliance to guarantee safety and avoid side effects. In 2007, prolonged-release tacrolimus was launched in Europe to improve compliance. In this prospective observational crossover single-center trial, we analyzed effects and side effects of prolonged-release tacrolimus in OLT patients.

METHODS

LT patients at our center were included if they were older than l8 years of age, had had the procedure at least 6 months prior, and were outpatients currently on twice-daily tacrolimus. Patients were observed for 6 months before switching to once-daily tacrolimus. Patient history, clinical examination, and laboratory examinations were recorded on inclusion as well as after 3, 6, 9, 12, and 18 months.

RESULTS

The rates of rejection, hypertension, hypercholesterolemia, and diabetes mellitus were compared during twice-daily and once-daily tacrolimus. Similarly, laboratory parameters were identical during both periods with the exception of glycated hemoglobin, which was significantly elevated under once-daily tacrolimus (P = .00l).

CONCLUSION

Converting patients to extended-release tacrolimus with was safe in terms of rejection, hypertension, and hypercholesterolemia as well as renal and liver functions. Further investigations concerning pharmacokinetics and glucose metabolism will be needed to evaluate prolonged-release tacrolimus.

The effect of third-party reporting on adoption of evidence-based mesalazine regimens in ulcerative colitis: an observational study

BACKGROUND AND AIMS

The optimal mesalazine dosing strategy for ulcerative colitis (UC) continues to evolve. The current study aimed to explore whether documenting drug use could prompt changes in prescribing habits.

METHODS

In a multicenter, prospective, observational study, outpatients with active or quiescent UC were enrolled if they were receiving, or were planned to receive, sustained release mesalazine microgranules (Pentasa). Clinical and prescribing data were collected at study entry, after 2 and 8 weeks. Physician-reported influences on prescribing decisions were recorded at study entry.

RESULTS

360 patients were analyzed (203 active UC, 157 remission). Prior to study entry, the range of oral mesalazine doses was 0.50-6.00 g/day in active UC patients, and 0.50-4.00 g/day for patients in remission. These changed to 1.50-5.00 g/day and 1.00-4.00 g/day, respectively, at study entry with little change thereafter. Use of a single daily mesalazine dose increased from 16.7% to 58.0% of active cases during the study, and from 5.9% to 46.8% in remission cases. Gastroenterologists reported that their basis for prescription decision-making was most frequently medical experience (80.8%), followed by guidelines (67.2%), further education or colleagues' recommendations (50.0%) and current study results (20.0%).

CONCLUSION

In this analysis of mesalazine dosing in routine clinical practice, there was an improvement in adherence to European Crohn's and Colitis Organisation (ECCO) guidelines and in use of once-daily dosing, consistent with recent trial results, following documentation of dosing regimens. Written reporting of drug dosing schedules should be considered fundamental for chronic, complex diseases such as UC.

Strategies of targeting oral drug delivery systems to the colon and their potential use for the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related death in both men and women. Often, surgical intervention remains the choice in treating CRC. Traditional dosage forms used for treating CRC deliver drug to wanted as well as unwanted sites of drug action resulting in several adverse side effects. Targeted oral drug delivery systems are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific delivery of a drug to colon increases its concentration at the target site, and thus requires a lower dose with reduced incidence of side effects. The major obstacle to be overcome for successful targeting of drug to colon through oral route is that drug absorption/degradation must be avoided in stomach and small intestine before the dosage form reaches colon. The review includes discussion of physiological factors that must be considered when targeting drugs directly to colorectal region, an outline on drugs used for treatment and prevention of CRC, and a brief description of various types of colon-targeted oral drug delivery systems. The focus is on the assessment of various formulation approaches being investigated for oral colon-specific delivery of drugs used in the treatment and prevention of CRC.

Common misconceptions about 5-aminosalicylates and thiopurines in inflammatory bowel disease

Misconceptions are common in the care of patients with inflammatory bowel disease (IBD). In this paper, we state the most commonly found misconceptions in clinical practice and deal with the use of 5-aminosalicylates and thiopurines, to review the related scientific evidence, and make appropriate recommendations. Prevention of errors needs knowledge to avoid making such errors through ignorance. However, the amount of knowledge is increasing so quickly that one new danger is an overabundance of information. IBD is a model of a very complex disease and our goal with this review is to summarize the key evidence for the most common daily clinical problems. With regard to the use of 5-aminosalicylates, the best practice may to be consider abandoning the use of these drugs in patients with small bowel Crohn’ s disease. The combined approach with oral plus topical 5-aminosalicylates should be the first-line therapy in patients with active ulcerative colitis; once-daily treatment should be offered as a first choice regimen due to its better compliance and higher efficacy. With regard to thiopurines, they seem to be as effective in ulcerative colitis as in Crohn’ s disease. Underdosing of thiopurines is a form of undertreatment. Thiopurines should probably be continued indefinitely because their withdrawal is associated with a high risk of relapse. Mercaptopurine is a safe alternative in patients with digestive intolerance or hepatotoxicity due to azathioprine. Finally, thiopurine methyltransferase (TPMT) screening cannot substitute for regular monitoring because the majority of cases of myelotoxicity are not TPMT-related.

Review article: remission rates achievable by current therapies for inflammatory bowel disease

BACKGROUND

New medical therapies have improved outlook in inflammatory bowel disease but published impact on surgical rates has been modest suggesting that many patients are still not attaining remission.

AIM

To review remission rates with current medical treatments for inflammatory bowel disease.

METHODS

We searched MEDLINE (source PUBMED, 1966 to January, 2011).

RESULTS

Induction and maintenance of remission was observed in 20% (range, 9-29.5%) and 53% (range, 36.8-59.6%) of ulcerative colitis (UC) patients treated with oral 5-ASA derivatives. Induction of remission was noted in 52% (range, 48-58%) of Crohn's disease (CD) patients and 54% of UC patients treated with steroids in population-based cohorts. Maintenance of remission was reported in 71% (range, 56-95%) of CD patients on azathioprine over a 6-month to 2-year period and in 60% (range, 41.7-82.4%) in UC at 1 year or longer. Induction and maintenance of remission was noted in 39% (range, 19.3-66.7%) and 70% (range, 39-90%) of CD patients on methotrexate over a 40-week period. Induction of remission was reported in 32% (range, 25-48%), 26% (range, 18-36%) and 20% (range, 19-23%) of CD patients on infliximab, adalimumab or certolizumab pegol, respectively. The corresponding figures were 45% (range, 39-59%), 43% (range, 40-47%) and 47.9% at weeks 20-30 among initial responders. Induction of remission was observed in 33% (range, 27.5-38.8%) and 18.5% of UC patients on infliximab or adalimumab, respectively. Maintenance of remission was noted in 33% (range, 25.6-36.9%) of UC patients on infliximab at week 30. Approximately one-fifth of CD and UC patients treated with biologicals require intestinal resection after 2-5 years in referral-centre studies.

CONCLUSION

In the era of biologics, the proportion of patients with inflammatory bowel disease not entering remission remains high.

A dynamic model of once-daily 5-aminosalicylic acid predicts clinical efficacy

New once daily mesalamine formulations may improve adherence to medication usage. Response to Asacol and other forms of 5-aminosalicyclic acid (5-ASA) is better correlated with tissue concentrations and best predicted by concentrations of the drug within the lumen of the colon. Our group used computer simulation to predict colonic 5-ASA levels after Asacol administration. In our study, the model simulated Asacol distribution in the healthy colon, and during quiescent and active ulcerative colitis. An Asacol dosage of 800 mg, three times a day, was compared to 2400 mg given once a day. Under ideal conditions, the predicted maximum drug in the total colon and individual colonic segments over 100 d differed by less than 3% between single and multiple doses. Despite changes in motility and defection rates, the predicted maximum and average 5-ASA concentrations in the total colon and individual colonic segments differed by less than 10% between dosing regimens. Asymmetric distribution of 5-ASA in the colon was influenced by frequency of bowel movements and colonic transit rate. In active colitis, sigmoid 5-ASA concentration becomes negligible. Our model supports once daily administration of Asacol as standard treatment for ulcerative colitis.