Novel biological therapies for inflammatory bowel disease

Dual TNF-α/Cyclin D1 Gene Silencing With an Oral Polymeric Microparticle System as a Novel Strategy for the Treatment of Inflammatory Bowel Disease

OBJECTIVES:

RNA silencing utilizing short interfering RNA (siRNA) offers a new and exciting means to overcome the limitations of current treatment options of many diseases. However, delivery of these molecules still poses a great challenge to date.

METHODS:

In the present study, a multicompartmental biodegradable polymer-based nanoparticles-in-microsphere oral system (NiMOS) using gelatin nanoparticles encapsulating a combination of siRNA duplexes specifically targeted against tumor necrosis factor-α (TNF-α) and cyclin D1 (Ccnd1) was employed to study its effects on a dextran sulfate sodium (DSS)-induced acute colitis mouse model mimicking inflammatory bowel disease (IBD). DSS colitis-bearing animals were divided into several control and treatment groups and received either no treatment, blank NiMOS, NiMOS-encapsulating inactive (scrambled), active TNF-α silencing, CyD1 silencing siRNA, or a combination of both active siRNAs by repeated oral administration of three NiMOS doses.

RESULTS:

Successful gene silencing with the aid of dual siRNA treatment led to decreased colonic levels of TNF-α or CyD1, suppressed expression of certain pro-inflammatory cytokines (interleukin-1α and -β, interferon-γ), an increase in body weight, and reduced tissue myeloperoxidase activity, while the silencing effect of CyD1 siRNA or the dual treatment was more potent than that of TNF-α siRNA alone.

CONCLUSION:

Results of this study demonstrate the therapeutic potential of a NiMOS-based oral combined TNF-α and CyD1 gene silencing system for the treatment of IBD as shown in an acute colitis model.

Oral TNF-α gene silencing using a polymeric microsphere-based delivery system for the treatment of inflammatory bowel disease

The purpose of this study was to evaluate down-regulation of tumor necrosis factor (TNF)-α by oral RNA interference therapy. Control (scrambled sequence) or TNF-α specific small interfering RNA (siRNA) was encapsulated in type B gelatin nanoparticles and further entrapped in poly(epsilon-caprolactone) (PCL) microspheres to form a nanoparticles-in-microsphere oral system (NiMOS). Upon confirmation of the dextran sulfate sodium (DSS)-induced acute colitis model, mice were divided into several treatment groups receiving no treatment, blank NiMOS, NiMOS with scramble siRNA, or NiMOS with TNF-α silencing siRNA by oral administration. Successful gene silencing led to decreased colonic levels of TNF-α, suppressed expression of other pro-inflammatory cytokines (e.g., interleukin (IL)-1β, interferon (IFN)-γ) and chemokines (MCP-1), an increase in body weight, and reduced tissue myeloperoxidase activity. Results of this study established the clinical potential of a NiMOS-based oral TNF-α gene silencing system for the treatment of inflammatory bowel disease as demonstrated in an acute colitis model.

Meta-analysis: remission and response from control arms of randomized trials of biological therapies for active luminal Crohn's disease

BACKGROUND

Remission and response are the main outcomes to evaluate the efficacy of new treatments for Crohn's disease (CD).

AIM

To explain variation of remission and response rates in active luminal CD.

METHODS

We studied control patients from trials of biological therapies through articles retrieved by MEDLINE search (from 1997 to 2007) and by bibliography review. Thousand nine hundred and thirteen control patients from 28 trials were identified; data were extracted by three independent observers and pooled by DerSimonian and Laird random effect model; factors influencing remission and clinical response were explored by metaregression for aggregated data.

RESULTS

The pooled control rates of remission and response were 17% and 33%, respectively, both with significant heterogeneity among studies (P < 0.0001). At metaregression, the time of primary outcome evaluation was associated with remission, whereas the trial's criteria for defining response and publication year were predictors of response. CDAI score, CRP levels or other clinical variables related with disease activity or concomitant medications were not significant factors.

CONCLUSIONS

Populations used as 'add-on' treatment comparator in trials of biological therapies for active luminal CD are poorly characterized and outcomes are heterogeneous. Planning of future trials will require better description of patients and concomitant therapies, blinding of outcome assessors and homogeneous criteria of outcome definition.

Late-breaking news from the "4th International Meeting on Inflammatory Bowel Diseases" Capri, 2006

At the "4th International Meeting on Inflammatory Bowel Diseases: on the Way to New Therapies," Capri, 2006, genetics, bacteria-host interactions, immunomodulation, and tissue response were discussed deeply in order to understand, rationalize, and develop novel therapies. About genetics, the importance of a better understanding of the nature of known loci and of the putative associations was stressed. It was confirmed that genotype-phenotype associations in inflammatory bowel disease (IBD) have important clinical and therapeutic implications. The importance of the search for dominant bacterial antigens in chronic immune-mediated intestinal inflammation emerged, as well as knowledge of cellular and molecular mechanisms of bacterial-host interactions. It was discussed how innate and adaptive immunity signaling events can perpetuate chronic inflammation. Signal transduction pathways provide an intracellular mechanism by which cells respond and adapt to environmental stress. The identification of these signals have led to a greater understanding of the pathogenesis of IBD and pointed to potential therapeutic targets. It was shown that immune homeostasis is lost in IBD, resulting in a complex tissue response involving the action of immune and nonimmune cells. The nonimmune tissue response in IBD could be regarded as a new target for control of chronic intestinal inflammation. The changing role of biotherapy in IBD was widely discussed and in particular the anti-TNF-alpha monoclonal antibodies. Granulocyte-colony stimulating factor (GM-CSF) and stem cells therapies were also discussed. The risk-to-benefit ratio of the novel therapies was analyzed in detail. Finally, future directions for basic science and the unmet needs for clinical practice were presented.