ATC code: G03AD02 The most recent approval by FDA is Ulipristal Acetate, approved on August 13th 2010 under the trade name Ella. Ulipristal Acetate (previously known by the research code CDB-2914 or VA-2914) is a progesterone agonist/antagonist emergency contraceptive, indicated for prevention of pregnancy following unprotected intercourse or known or suspected contraceptive failure. This drug is a selective progesterone receptor modulator (SPRM) with antagonist and partial agonist effects (a progesterone agonist/antagonist) at the progesterone receptor (PR, NR3C3) (Uniprot code: P06401 ). The Progesterone Receptor is a member of a very significant family of proteins for drug discovery, the Nuclear Receptors , a family of around 50 genes which are transcription factors , the transcription by NRs is usually ligand regulated. Ulipristal Acetate prevents progesterone, the endogenous ligand, from occupying its receptor. Ulpristal Acetate binds in the ligand binding domain (LBD) of PR ...