Currently, several selective small-molecule ALK2 inhibitors are being investigated in phase 2 trials as potential therapies for FOP, including the STOPFOP study of Saracatinib (NCT04307953), the FALKON study of IPN60130/Fidrisertib (NCT05039515), and the PROGRESS study of INCB000928/Zilurgisertib (NCT05090891). Here, ACVR1 is linked to fibrodysplasia ossificans progressiva.