A-4250 (odevixibat) is a selective inhibitor of the ileal bile acid transporter (IBAT) that acts locally in the gut. Ileum absorbs glyco-and taurine-conjugated forms of the bile salts. IBAT is the first step in absorption at the brush-border membrane. A-4250 works by decreasing the re-absorption of bile acids from the small intestine to the liver, whichreduces the toxic levels of bile acids during the progression of the disease. It exhibits therapeutic intervention by checking the transport of bile acids. Studies show that A-4250 has the potential to decrease the damage in the liver cells and the development of fibrosis/cirrhosis of the liver known to occur in progressive familial intrahepatic cholestasis. A-4250 is a designated orphan drug in the USA for October 2012. A-4250 is a designated orphan drug in the EU for October 2016. A-4250 was awarded PRIME status for PFIC by EMA in October 2016. A-4250 is in phase II clinical trials by Albireo for the treatment of primary biliary cirrhosis (PBC) and cholestatic pruritus. In an open label Phase 2 study in children with cholestatic liver disease and pruritus, odevixibat showed reductions in serum bile acids and pruritus in most patients and exhibited a favorable overall tolerability profile.

Maralixibat (Livmarli™) is a potent, apical, sodium‐dependent, bile acid transporter competitive inhibitor with minimal systemic absorption being developed by Mirum Pharmaceuticals for the treatment of rare cholestatic liver diseases including Alagille syndrome (ALGS), progressive familial intrahepatic cholestasis (PFIC) and biliary atresia. Maralixibat received its first approval on 29 September 2021, in the USA, for use in the treatment of cholestatic pruritus in patients with ALGS 1 year of age and older. Maralixibat is also under regulatory review for ALGS in Europe, and clinical development for cholestatic liver disorders including ALGS in patients under 1 year of age, PFIC and biliary atresia is continuing in several other countries. This article summarises the milestones in the development of maralixibat leading to this first approval for ALGS.

GSK-2330672 (linerixibat) is a nonabsorbable apical sodium-dependent bile acid transporter. This compound is being evaluated for treatment in patients with type 2 diabetes. In animal models of type 2 diabetes, it lowers glucose levels. GSK-2330672 also improves glucose and lipids in diabetes patients, but a high incidence of gastrointestinal adverse events (such as diarrhea) has been reported. Efficacy of GSK-2330672 in patients with primary biliary cholangitis that develop itch (pruritus) has also been examined. However, long-term used might be problematic because of the gastrointestinal adverse events.

A-4250 (odevixibat) is a selective inhibitor of the ileal bile acid transporter (IBAT) that acts locally in the gut. Ileum absorbs glyco-and taurine-conjugated forms of the bile salts. IBAT is the first step in absorption at the brush-border membrane. A-4250 works by decreasing the re-absorption of bile acids from the small intestine to the liver, whichreduces the toxic levels of bile acids during the progression of the disease. It exhibits therapeutic intervention by checking the transport of bile acids. Studies show that A-4250 has the potential to decrease the damage in the liver cells and the development of fibrosis/cirrhosis of the liver known to occur in progressive familial intrahepatic cholestasis. A-4250 is a designated orphan drug in the USA for October 2012. A-4250 is a designated orphan drug in the EU for October 2016. A-4250 was awarded PRIME status for PFIC by EMA in October 2016. A-4250 is in phase II clinical trials by Albireo for the treatment of primary biliary cirrhosis (PBC) and cholestatic pruritus. In an open label Phase 2 study in children with cholestatic liver disease and pruritus, odevixibat showed reductions in serum bile acids and pruritus in most patients and exhibited a favorable overall tolerability profile.

Maralixibat (Livmarli™) is a potent, apical, sodium‐dependent, bile acid transporter competitive inhibitor with minimal systemic absorption being developed by Mirum Pharmaceuticals for the treatment of rare cholestatic liver diseases including Alagille syndrome (ALGS), progressive familial intrahepatic cholestasis (PFIC) and biliary atresia. Maralixibat received its first approval on 29 September 2021, in the USA, for use in the treatment of cholestatic pruritus in patients with ALGS 1 year of age and older. Maralixibat is also under regulatory review for ALGS in Europe, and clinical development for cholestatic liver disorders including ALGS in patients under 1 year of age, PFIC and biliary atresia is continuing in several other countries. This article summarises the milestones in the development of maralixibat leading to this first approval for ALGS.