Macrocyclic compounds of formula (I), in which B1 and X1 taken together are alkylene which is unsubstituted or substituted with ═O and having one CH2 moiety unreplaced or replaced with CH═CH, O, NH or N(alkyl), which inhibit the activity of antiapoptotic Bcl-2 family protein members, compositions containing the compounds and methods of treating diseases during which are expressed one or more than one of an anti-apoptotic family protein member are disclosed.