Pharmaceutical compounds

The invention provides the use of an aryl-substituted 1,1-diphosphonate for the manufacture of a medicament for stimulating bone formation; said aryl-susbtituted 1,1-diphosphonate being a compound of formula (I) in which A is (a) or (b) or (c) where: X is H, an alkyl group having from 1 to 4 carbon atoms; X , X and X are identical or different and are H, a straight or branched alkyl or alkoxy group having from 1 to 8 carbon atoms, X is H, a straight or branched alkyl group having from 1 to 8 carbon atoms, an optionally substituted benzyl group, X is H, a straight or branched alkyl group having from 1 to 8 carbon atoms, X is H or an alkyl group having from 1 to 4 carbon atoms, q is 0 or 1, R , R , R and R are identical or different and are H, a straight, branched or cyclic alkyl group comprising from 1 to 8 carbon atoms, or R , R and R and R may form an alkylidenedioxy ring comprising from 2 to 8 carbon atoms, L is -CH=CH-CH2-, -(CH2)n, -O(CH2)n, -S-, -SO2, -S(CH2)n-, -SO2(CH2)n, where n is an integer from 1 to 7, or together with B, L is (CH=CH)k-(CH2)dCH=where k is 0 or 1 and d is an integrer from 0 to 4, -B is H, an alkyl group having from 1 to 4 carbon atoms, -t is 0 or 1, with the proviso that t is 0 only when L, together with B, is (CH=CH)k-(CH2)d-CH= where k and d are as described above, and with the further proviso that when L is -(CH2)n or -S-, at least one of R , R , R and R is other than hydrogen.