Clesacostat (ACY-1215) is a selective inhibitor of histone deacetylase 6 (HDAC6), primarily used in research settings for its anti-inflammatory, immunomodulatory, and neuroprotective properties. It has been investigated for its ability to inhibit HDAC6 involved in inflammatory pathways, protein aggregation, and axonal transport, making it a candidate for studying conditions like arthritis, autoimmune diseases, multiple myeloma, Alzheimer's disease, and Huntington's disease. As a tool compound in preclinical studies, it helps understand cytokine regulation, immune cell activity, and gene expression modulation. Its applications remain largely experimental, with ongoing studies exploring its efficacy and safety in cellular, animal, and clinical models.