Privately held Arog Pharmaceuticals Inc. won orphan drug status in Europe for crenolanib to treat acute myeloid leukemia (AML) and soft-tissue sarcoma. An orally available benzimidazole, crenolanib is a type I kinase inhibitor that goes after the signaling of wild-type and mutant isoforms of class III receptor tyrosine kinases FLT3 and platelet-derived growth factor receptor (PDGFR) alpha/beta.