Although progressive familial intrahepatic cholestasis (PFIC) tends to draw more hoopla in the race, and Mirum Pharmaceuticals Inc. looks due to beat Albireo Pharma Inc. to market in Alagille syndrome (ALGS), the most revenue likely lies in a third rare pediatric liver disease where the firms compete: biliary atresia (BA). Mirum, of Foster City, Calif., completed its rolling NDA several weeks ago for maralixibat – an inhibitor of the apical sodium-dependent bile acid transporter designed to drive more excretion of bile acids as a way of lowering their level systemically – in cholestatic pruritus in patients with ALGS one year of age and older.