“Mucosal healing” in ulcerative colitis: Between clinical evidence and market suggestion

Twenty-five years of biologicals in IBD: What´s all the hype about?

Twenty-five years ago the field was revolutionized by the introduction of infliximab as the first hybrid anti-TNF-antibody. Subsequently, other humanized anti-TNFs were developed and marketed, followed by antibodies to new targets including integrins (vedolizumab) and interleukin 12/23 (ustekinumab). All these so-called biologicals were shown in registrational trials to induce remission superior to placebo but consistently were effective in only a minority of patients. Even though in most trials only the responders were selected to continue on the respective medication for maintenance, many experienced a secondary loss of response and only a minority of usually <25% of the initial cohort achieved long-term (1 year) remission. In 'real life studies', the outcome was somewhat better, probably due to proper selection of patients and open, mostly retrospective study designs. A clear benefit of biologicals is apparent in otherwise treatment refractory patients, in extraintestinal manifestations and in Crohn´s disease (CD) with fistulizing complications. Biologicals achieve mucosal healing (MH) more often than corticosteroids or thiopurines, and MH is associated with improved prognosis. However, this does not justify escalating treatment until MH is reached since controlled trials proving this point of 'treat to target' are lacking both in ulcerative colitis and CD. Surgical rates have decreased with increasing use of biologicals, but disease progression has not been proven to improve. With the exception of opportunistic infections, serious adverse events are rare. In conclusion, biologicals have changed the scene considerably and expanded our armamentarium, but there is also a marketing hype fostering expectations without evidence.

Repeated Oral Administration of a KDEL-tagged Recombinant Cholera Toxin B Subunit Effectively Mitigates DSS Colitis Despite a Robust Immunogenic Response

Cholera toxin B subunit (CTB), a non-toxic homopentameric component of Vibrio cholerae holotoxin, is an oral cholera vaccine antigen that induces an anti-toxin antibody response. Recently, we demonstrated that a recombinant CTB variant with a Lys-Asp-Glu-Leu (KDEL) endoplasmic reticulum retention motif (CTB-KDEL) exhibits colon mucosal healing effects that have therapeutic implications for inflammatory bowel disease (IBD). Herein, we investigated the feasibility of CTB-KDEL for the treatment of chronic colitis. We found that weekly oral administration of CTB-KDEL, dosed before or after the onset of chronic colitis, induced by repeated dextran sodium sulfate (DSS) exposure, could significantly reduce disease activity index scores, intestinal permeability, inflammation, and histological signs of chronicity. To address the consequences of immunogenicity, mice (C57BL/6 or C3H/HeJ strains) were pre-exposed to CTB-KDEL then subjected to DSS colitis and CTB-KDEL treatment. While the pre-dosing of CTB-KDEL elicited high-titer anti-drug antibodies (ADAs) of the immunoglobin A (IgA) isotype in the intestine of C57BL/6 mice, the therapeutic effects of CTB-KDEL were similar to those observed in C3H/HeJ mice, which showed minimal ADAs under the same experimental conditions. Thus, the immunogenicity of CTB-KDEL does not seem to impede the protein's mucosal healing efficacy. These results support the development of CTB-KDEL for IBD therapy.

MMX® technology and its applications in gastrointestinal diseases

The Multimatrix^® (MMX^®) preparation MMX^® is a recently obtained drug formulation developed to facilitate release of high concentrations of active drugs into the colon, with a homogeneous distribution along all colonic segments, particularly the most distal ones; the distal colonic tracts, indeed, are the most difficult to reach in significant amounts when a drug is given orally. The MMX^® formulation is characterized by a lipophilic matrix dispersed in a hydrophilic structure. Indeed, in the last few years, MMX^® technology has been widely used in the development of various drugs for the treatment of inflammatory and infectious gastrointestinal diseases localized in the colon. In particular, MMX^® mesalamine, budesonide and parnaparin formulations have been investigated in patients with ulcerative colitis, and the first two have reached worldwide registration for the treatment of this disease. Moreover, MMX^®-rifamycin is being positively tested in the treatment of colonic bacterial infections, including traveler's diarrhea. MMX^® technology is, thus, proving to be a very effective formulation for the treatment of various colonic diseases. This effectiveness has been related not only to specific colonic delivery, but also to its ability to act in a once-daily dosage, thus favouring patients' adherence to prescribed schedules of treatment. The effective delivery of the active molecule to the site of need in the colon is also associated with very low systemic absorption and very low rates of adverse events (AEs). In this paper, we have reviewed all clinical trials performed with an MMX^®-bound drug and all possible real-life reports, in order to give an overall evaluation of MMX^®.

Endoscopic scores for inflammatory bowel disease in the era of 'mucosal healing': Old problem, new perspectives

The importance of the endoscopic evaluation in inflammatory bowel disease (IBD) management has been recognized for many years. However, the modalities for reporting endoscopic activity represent an ongoing challenge. To address this, several endoscopic scores have been proposed. Very few have been properly validated, and the use of such tools remains sub-optimal and is mainly restricted to clinical trials. In recent years, a growing emphasis of the concept of 'mucosal healing' as a prognostic marker and therapeutic goal has increased the need for a more accurate definition of endoscopic activity in both ulcerative colitis (UC) and Crohn's Disease (CD). In the present review, the evolution of the challenges related to endoscopic scores in IBD has been analyzed, with particular attention paid to the renewed relevance of endoscopic activity in recent years. Currently, despite the growing relevance of endoscopic activity, evaluating this activity in IBD is still a challenge. The implementation of efficacious endoscopic scores and a better definition of the absence of activity (mucosal healing) are needed.

Budesonide Multi-matrix for the Treatment of Patients with Ulcerative Colitis

Ulcerative colitis (UC) is a chronic idiopathic inflammatory disorder in which patients cycle between active disease and remission. Budesonide multi-matrix (MMX) is an oral second-generation corticosteroid designed to deliver active drug throughout the colon. In pharmacokinetic studies, the mean relative absorption of budesonide in the region between the ascending colon and the descending/sigmoid colon was 95.9 %. In 2 identically designed, phase 3 studies (CORE I and II), budesonide MMX 9 mg once daily was efficacious and well tolerated for induction of remission of mild to moderate UC. Clinical and endoscopic remission rates were 17.9 % (CORE I) and 17.4 % (CORE II) for budesonide MMX 9 mg compared with 7.4 and 4.5 %, respectively, with placebo (p < 0.05, budesonide MMX 9 mg vs. placebo in both studies), 12.1 % with mesalamine 2.4 g, and 12.6 % with budesonide controlled ileal release capsules 9 mg. A 12-month maintenance therapy study suggested that budesonide MMX 6 mg may prolong time to clinical relapse: Median time was >1 year with budesonide MMX 6 mg versus 181 days (p = 0.02) with placebo; however, further studies are needed. In the CORE studies, budesonide MMX exhibited a favorable safety profile; the majority of adverse events were mild or moderate in intensity, and serious adverse events were uncommon. Furthermore, rates of potential glucocorticoid-related adverse events were comparable across treatment groups. The long-term (12-month) safety of budesonide MMX appears to be comparable with placebo. Data support budesonide MMX in the management algorithm of UC.

Mucosal healing in the era of biologic agents in treatment of inflammatory bowel disease

Mucosal healing has been a central issue in inflammatory bowel disease (IBD) for the last years, and has been proposed to be included as the new treatment goal in IBD. The molecular understanding of both the disruption and the healing of the intestinal epithelial cell lining and the mucosal barrier in IBD is complex and only partly understood. There is no general agreement on how to define healed mucosa, but there is a general acceptance that clinicians should use endoscopy and imaging technique in their assessments. Mucosal healing is an old concept that has been actualized in the present era of the highly effective biological agents. Randomized clinical studies with mucosal healing as end-point parameters have been reported, and early mucosal healing has been associated with low complication rates. We are waiting for documentation of whether treatment to healed mucosa can change the natural course of IBD. The concept of immunological remission has recently been introduced and can be the new treatment goal and one of several criteria for discontinuation of biological treatment in IBD. In conclusion, mucosal healing is a fairly novel concept and goal for biological treatment of IBD. There is a need for a standardization of its assessment and validation of the prognostic value.