Efficacy of the bisphosphonate APD∗∗(Note on the nomenclature: Traditional abbreviations for identifying compounds have been used in the text. According to IUPAC: Nomenclature of Organic Chemistry, Sections A-H (Pergamon Press, Oxford, 1979), the new abbreviations are as follows: APD = AHP1BP: 3-amino-1-hydroxypropylidene-1,1-bisphosphonate EHDP = HEBP: 1-hydroxyethylidene-1,1-bisphosphonate Cl2MDP = Cl2MBP: Dichloromethylenebisphosphonate. in the control of Paget's bone disease