QTX-153

QTX-153 is a preclinical **small-molecule HDAC6 inhibitor** being developed by Quimatryx, with co-development support from Kærtor, for central nervous system and rare neurodevelopmental disorders. Public descriptions identify it as a brain-penetrant inhibitor of histone deacetylase 6 designed from Quimatryx's HDAC6 program, with recent sponsor-linked disclosures emphasizing **Rett syndrome** and broader historical mentions of **amyotrophic lateral sclerosis**, **Charcot-Marie-Tooth disease**, and other neurologic indications. Mechanistically, QTX-153 is intended to inhibit HDAC6, a cytoplasmic deacetylase involved in neuronal function, microtubule dynamics, and protein homeostasis; in Rett syndrome models, HDAC6 overactivity has been described as a disease-relevant feature downstream of **MECP2** dysfunction. Available public evidence supports that the program remains **preclinical** and has not yet been identified in public clinical trial registries as an active human-stage asset.