We previously reported medicinal chemistry efforts that identified MK-5204, an orally efficacious β-1,3-glucan synthesis inhibitor derived from the natural product enfumafungin. Further extensive optimization of the C2 triazole substituent identified 4-pyridyl as the preferred replacement for the carboxamide of MK-5204, leading to improvements in antifungal activity in the presence of serum, and increased oral exposure. Reoptimizing the aminoether at C3 in the presence of this newly discovered C2 substituent, confirmed that the (R) t-butyl, methyl aminoether of MK-5204 provided the best balance of these two key parameters, culminating in the discovery of ibrexafungerp, which is currently in phase III clinical trials. Ibrexafungerp displayed significantly improved oral efficacy in murine infection models, making it a superior candidate for clinical development as an oral treatment for Candida and Aspergillus infections.

我们之前报道了确定 MK-5204 的药物化学工作，MK-5204 是一种口服有效的 β-1,3-葡聚糖合成抑制剂，来源于天然产物恩夫马芬净。C2 三唑取代基的进一步优化确定 4-吡啶基是 MK-5204 甲酰胺的首选替代品，导致在血清存在下的抗真菌活性提高，并增加口服暴露。在这个新发现的 C2 取代基的存在下重新优化 C3 处的氨基醚，证实（R) MK-5204 的叔丁基甲基氨基醚提供了这两个关键参数的最佳平衡，最终发现了 ibrexafungerp，目前正处于 III 期临床试验。Ibrexafungerp 在小鼠感染模型中显示出显着改善的口服功效，使其成为临床开发的优秀候选药物，作为念珠菌和曲霉菌感染的口服治疗药物。