Huntington’s disease (HD) is one of the serious neurodegenerative diseases and no disease modifiers are available to date. The correction of unbalanced kynurenine pathway metabolites may be useful to treat disease progression and kynurenine monooxygenase (KMO) is considered an ideal drug target. A couple of KMO inhibitors have been reported, but their brain permeability was very poor. We found pyridazinylsulfonamide as a novel lead compound, and it was optimized to the brain-permeable and highly potent KMO inhibitor 12, which was equipotent with CHDI-340246 and superior to CHDI-340246 in terms of brain penetration. Compound 12 was effective in R6/2 mice (HD model mice), i.e. neuroprotective kynurenic acid was increased, whereas neurotoxic 3-hydroxykynurenine was suppressed. In addition, impaired cognitive function was improved. Therefore, the brain-permeable KMO inhibitor was considered to be a disease modifier for HD treatment.

亨廷顿病（HD）是一种严重的神经退行性疾病，迄今为止还没有可用的疾病调节剂。纠正不平衡的犬尿氨酸途径代谢物可能有助于治疗疾病进展，犬尿氨酸单加氧酶（KMO）被认为是理想的药物靶点。已经报道了几种 KMO 抑制剂，但它们的脑通透性非常差。我们发现哒嗪基磺酰胺作为一种新型先导化合物，并将其优化为具有脑渗透性的高效 KMO 抑制剂12 ，其与 CHDI-340246 等效，并且在脑渗透性方面优于 CHDI-340246。化合物12对R6/2小鼠(HD模型小鼠)有效，即。具有神经保护作用的犬尿氨酸增加，而具有神经毒性的 3-羟基犬尿氨酸则受到抑制。此外，受损的认知功能也得到改善。因此，脑渗透性KMO抑制剂被认为是HD治疗的疾病调节剂。