In 2010, when Sanofi SA signed a potential $560 million deal to get its hands on JAK2 inhibitor fedratinib (then known as TG-101348) via the buyout of Targegen Inc., the latter's director of research, John Hood, had high hopes for patients with myelofibrosis (MF) and polycythemia vera (PV). Several years later, though, safety problems turned up at the phase III stage, the FDA put fedratinib on clinical hold, and Sanofi dropped fedratinib like a hot potato.