Equimolar doses of balsalazide and mesalamine: are we comparing apples and oranges?

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.

Current and emerging maintenance therapies for ulcerative colitis

Ulcerative colitis (UC) is a chronic idiopathic intestinal disease that requires life-long maintenance therapy to maintain clinical remission. This article reviews the current literature on maintenance treatments in UC. It examines the natural history of the condition and the proposed benefits of treatment. These include improving quality of life parameters, decreasing corticosteroid intake, the prevention of relapse, the prevention of colorectal cancer and the avoidance of colectomy. The immunosuppressive era appears to be reducing the need for elective colectomy in UC. The article explores the classes of drug currently used for maintenance of UC, reviews the literature around adherence issues, and summarizes emerging agents in this space.

Improving delivery of aminosalicylates in ulcerative colitis: effect on patient outcomes

Developments in drug delivery technology have expanded the formulations of 5-aminosalicylic acid (5-ASA) available to clinicians over the last 50 years. Delivery of adequate doses of 5-ASA to the colon can be achieved by pH-dependent, delayed-release or pro-drug formulations. Despite some variations in the pharmacokinetics between individual preparations, the clinical effects in induction of response and maintenance of remission in ulcerative colitis appear to be consistent. Direct comparison studies between different preparations have yielded similar results in primary endpoints, although differences in secondary endpoints or post hoc analyses have been noted. The development of delivery methods that allow once-daily administration represents a potential means to improve the low medication adherence rates reported in patients with ulcerative colitis.

Balsalazide disodium for the treatment of ulcerative colitis

5-aminosalicylates remain the first-line treatment for patients with ulcerative colitis. A number of formulations are available for the treatment of active ulcerative colitis, including encapsulated mesalazine and mesalazine in combination with other molecules. Balsalazide is an aminosalicylate prodrug that releases mesalazine in the colon, thus exerting its multiple anti-inflammatory effects in areas of colitis. This review will examine the pharmacological and therapeutic features of balsalazide as an anti-inflammatory agent in ulcerative colitis. The introduction of novel aminosalicylate formulations and an appreciation of their molecular mode of action, has renewed interest in these agents in both maintenance of disease remission and cancer prevention.

Indications for 5-aminosalicylate in inflammatory bowel disease: is the body of evidence complete?

Mesalazine is a safe drug, although adverse events may be seen in a minority of patients. This applies also to pregnant women and children. The role of mesalazine in combination therapy to improve efficacy and concomitant drug pharmacokinetics, or in chemoprevention against inflammatory bowel disease (IBD)-related colonic carcinoma has not yet been completely elucidated. Therapeutic success of mesalazine may be optimized by a combination of high dose and low frequency of dosage to improve compliance. Therefore, due to its superior safety profile and pharmacokinetic characteristics, mesalazine is preferable to sulphasalazine. This paper reviews the literature concerning mechanisms of action, indications and off-label use, pharmacokinetic properties and formulations, therapeutic efficacy, compliance, paediatric indications, chemoprevention, and safety issues and adverse event profile of mesalazine treatment versus sulphasalazine. It also highlights these controversies in order to clarify the potential benefits of mesalazines in IBD therapy and evidence for its use.

Mesalamine delivery systems: do they really make much difference?

Sulfasalazine's role as the first-line of therapy in patients with inflammatory bowel disease has led to the development of other "designer" aminosalicylates, which eliminate the sulfa-moiety, and attempt to target the topically active mesalamine to the inflamed bowel. Olsalazine sodium and balsalazide disodium utilize the same azo-bond structure as sulfasalazine, requiring release of active mesalamine by colonic bacteria, and thus targeting these agents to the colon. Other mesalamine delivery systems use pH-dependant- or moisture-release to liberate the active mesalamine in both the large and small bowel. Direct application of mesalamine via enema or suppository is also effective in patients with distal colitis. The pharmacology and thus the undesirable drug absorption rates differ between drugs, although the clinical importance of these characteristics is debatable. Differences in release-systems, the impact of the fed and fasting state, and unique patient intolerances to individual agents demand an understanding of each of these products, and their application to patient therapy.

Medical therapy for ulcerative colitis 2004

There continue to be evolutionary changes in the management of ulcerative colitis despite the fact that, aside from a variety of aminosalicylate formulations, no new therapies have been approved over the past few decades. Nevertheless, debates continue regarding the optimization of treatment with aminosalicylates and the short- and long-term benefits of immunomodulation in ulcerative colitis. This article focuses on the most recent clinical studies pertaining to the management of ulcerative colitis and explores both the advances and controversies pertaining to aminosalicylate therapy, corticosteroids, cyclosporine, and the purine antimetabolites. Novel therapeutic approaches--including preliminary experience with biological therapies directed at tumor necrosis factor and other cytokines, adhesion molecules, growth factors, and probiotics--will be reviewed. Recent data regarding potential chemoprevention in long-standing ulcerative colitis and management of postoperative complications and pouchitis will also be discussed.

Review article: Oral, modified-release mesalazine formulations--proprietary versus generic

Products containing mesalazine have been used in the treatment of inflammatory bowel disease for many years. Many of the oral, modified-release products are reaching the point of patent expiration, and it is expected that several new 'generic' versions will be developed. As mesalazine acts topically, the drug needs to be available at the site of inflammation to be effective. For this reason, the currently available products have been developed with individual formulations so that physicians have a choice when matching the different release profiles to the site and extent of disease. As such, the current guidelines state that oral, delayed-release mesalazine formulations are not interchangeable and should be prescribed by their proprietary (brand) name. The standard regulatory assessment process for generic or 'copy' products, using systemic bioequivalence data, does not appear to be sufficient when evaluating topically acting, oral, modified-release products. We therefore recommend that the regulatory bodies should require that new, oral mesalazine products should be assessed by a combination of dissolution, bioequivalence and (a minimum of one) adequately powered, comparative trial to determine therapeutic equivalence. Of most importance here is that the assessment of new modified-release products is sufficiently rigorous to allow patients and physicians to be confident in their use.