Afegostat (INN; also known as isofagomine; planned trade name Plicera) was an experimental drug for the treatment of certain forms of Gaucher's disease that was being developed by Amicus Therapeutics and Shire plc until a failed clinical trial in 2009 led to termination of its development.

β-Glucocerebrosidase, an enzyme needed for the metabolisation of glucocerebroside, is misfolded in individuals with Gaucher's disease due to various mutations, one of which is called N370S.

Afegostat, an iminosugar, binds selectively to N370S glucocerebrosidase and restores its correct conformation and, consequently, enhances its activity about threefold.

They also signed a collaboration agreement with Shire plc related to this drug and others.

[4]: 13 It was granted orphan drug status by the European Medicines Agency (EMA)[5] and by the US FDA.