Isomers and 42-epimers of rapamycin alkyl ether analogs and pharmaceutically acceptable salts or prodrugs thereof, are immunomodulatory agents and are useful in the treatment of restenosis and immune and autoimmune diseases. Also disclosed are cancer-, fungal growth-, restenosis-, post-transplant tissue rejection- and immune- and autoimmune disease-inhibiting compositions and a method of inhibiting cancer, fungal growth, restenosis, post-transplant tissue rejection, and immune and autoimmune disease in a mammal. One particular preferred application of such isomers and 42-epimers of rapamycin alkyl ether analogs is in medicated devices and local vascular delivery wherein the stability and lipid solubility and subsequently diffusion through tissue and cell membranes are essential to the success of rapamycin containing combination devices.