Gut-directed therapeutics in inflammatory bowel disease.

PURPOSE OF REVIEW: Tissue-directed therapies (TDTs) provide potential advantages, including improved tolerance, safety, and efficacy. This review provides a conceptual framework for understanding intestinal TDT and summarizes the current landscape of TDT in inflammatory bowel disease (IBD).

RECENT FINDINGS: Vedolizumab, a mAb targeting the gut homing α4β7 integrin, served as revolutionary proof-of-principle for the power of advanced TDT in IBD. The development of other monoclonal antibodies targeting cell adhesion molecules followed including abrilumab (α4β7), etrolizumab (β7), and ontamalimab (MAdCAM-1). MORF-057, an oral small molecule inhibitor of α4β7, is now in development for ulcerative colitis. Efforts have also been made toward gut specific JAK inhibitors. Microbiome-based therapies, including engineered probiotics, bacteriophages, and postbiotics, are gaining interest. There are also a number of innovative drug delivery methods, including engineered yeast, hydrogels, and nanoparticles, and viral-based gene therapy.

SUMMARY: Gut-targeted therapies range from novel variations on traditional drugs (i.e., mAbs and small molecules) to microbiome-based therapeutics and engineered delivery systems. They can be used alone or in combination with currently available therapies. Future directions should focus on the development of tried-and-true modalities (mAbs, small molecules) as well as the microbiome and more innovative delivery systems.