Many thanks to Dong et al for their correspondence regarding our phase II randomized, controlled trial (NCT00550862) of obeticholic acid (OCA) in primary biliary cirrhosis (PBC).1 Notably, we were able to demonstrate biochemical efficacy of OCA in patients with PBC and inadequate response to ursodeoxycholic acid (UDCA), supporting the scientific rationale for using this semisynthetic analog of the primary bile acid chenodeoxycholic acid, which selectively activates the nuclear hormone receptor farnesoid X receptor.