BOS-589

BOS-589 (also known as GSK-3352589) is an orally administered small molecule that acts as a selective and colon-restricted inhibitor of the REarranged During Transfection (RET) growth factor receptor. It functions as a protein tyrosine kinase inhibitor and was developed for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D). The drug was originally developed by GlaxoSmithKline and later by Boston Pharmaceuticals. Clinical trials have reached Phase 2 for IBS-D but no further development has been reported since late 2022[1][2][6]. The mechanism of action involves inhibition of protein tyrosine kinases, specifically targeting RET in the gastrointestinal tract[1].