FD-IN-1 (Compound 12) is a factor D (FD) inhibitor with an IC50 of 12 nM. Complement FD, a highly specific S1 serine protease, plays a central role in the alternative complement pathway of the innate immune system. FD-IN-1 also inhibits factor XIa (FXIa) and Tryptase β2 with IC50s of 7.7 and 6.5µM, respectively[1].
[1]. Karki RG, et al. Design, Synthesis, and Preclinical Characterization of Selective Factor D Inhibitors Targeting the Alternative Complement Pathway. J Med Chem. 2019 May 9;62(9):4656-4668.