A rapamycin analog with an antioxidant moiety or a pharmaceutically acceptable salt or prodrug thereof, is an immunomodulatory agent and is 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, restenosois, post-transplant tissue rejection, and immune and autoimmune disease in a mammal. One particular preferred application of such antioxidant moiety containing rapamycin analog is in medicated devices wherein the stability and resistance to oxidative processes are essential to the success of rapamycin containing combination devices.