There are plenty of companies chasing the first U.S. FDA-approved treatment for the ultra-rare disease fibrodysplasia ossificans progressiva (FOP), but Ipsen SA stayed the course longer and won that approval Aug. 16 with Sohonos (palovarotene). Other companies have struggled to develop a treatment for FOP, which affects about 400 people in the U.S. and about 900 people worldwide. Some potential competitors are still in the clinic, trying to catch up.