ERA-63

ERA-63
Clinical data
Other names	3-Methylene-7α-methylethinylestradiol; 3-Methylene-7α-methyl-17α-ethynylestra-5(10)-en-17β-ol
Identifiers
	IUPAC name (7R,8R,9S,13S,14S,17R)-17-Ethynyl-7,13-dimethyl-3-methylidene-1,2,4,6,7,8,9,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthren-17-ol;
CAS Number	343248-86-2;
PubChem CID	87921126;
ChemSpider	8058857;
Chemical and physical data
Formula	C22H30O
Molar mass	310.481 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES C[C@@H]1CC2=C(CCC(=C)C2)[C@@H]3[C@@H]1[C@@H]4CC[C@]([C@]4(CC3)C)(C#C)O;
	InChI InChI=1S/C22H30O/c1-5-22(23)11-9-19-20-15(3)13-16-12-14(2)6-7-17(16)18(20)8-10-21(19,22)4/h1,15,18-20,23H,2,6-13H2,3-4H3/t15-,18-,19+,20-,21+,22+/m1/s1; Key:ITYURVXIFIQGDB-LADQHVHVSA-N;

ERA-63, also known as ORG-37663, as well as 3-methylene-7α-methyl-17α-ethynylestra-5(10)-en-17β-ol, is a synthetic, steroidal estrogen and a selective agonist of the ERα that was under development for the treatment of rheumatoid arthritis but was never marketed.^[2]^[1] The drug produced estrogenic effects but failed to show effectiveness for rheumatoid arthritis in a phase IIa clinical study.^[3]^[4] A large clinical trial also found that prinaberel (ERB-041), a selective ERβ agonist, was ineffective in the treatment of rheumatoid arthritis in spite of activity in preclinical models.^[4]