An updated patent review of histone deacetylase 6 inhibitors in neurodegenerative diseases (2020-2025).

INTRODUCTION: Histone deacetylase 6 (HDAC6) inhibitors have been widely explored as potential therapeutic approaches for oncological, autoimmune, cardiovascular, and neurodegenerative disorders. Recent clinical advancements in non-hydroxamate-based HDAC6 inhibitors highlight favorable drug-like properties and improved safety margins, enhancing suitability for long-term treatment.

AREA COVERED: This review updates the clinical status of HDAC6 inhibitors, the evolution of HDAC6 inhibitor pharmacophores, and patent disclosures from 2020 to 2025 identified by SciFinder search and manual confirmation. It also describes pharmacological assessment of new selective HDAC6 inhibitors in in vitro and in vivo models of neurodegenerative diseases.

EXPERT OPINION: Expanding interest in the development of 2-(difluoromethyl)-1,3,4-oxadiazole (1,3,4-DFMO) derivatives has yielded a diverse set of HDAC6 inhibitors with superior HDAC6 potency and selectivity and enhanced oral pharmacokinetic profiles. These characteristics have facilitated the identification of optimized drug candidates for treating both peripheral and central nervous neurodegenerative diseases. Among the emerging therapeutic applications, Charcot-Marie-Tooth (CMT) disease has become the leading focus in preclinical and early clinical development using HDAC6 inhibitors.