The present invention provides improved stents and other prostheses for delivering substances to vascular and other luminal and intracorporeal enviroments. In particular, the present invention provides luminal prostheses which allow for a programmed and controlled substance delivery protocols for a variety of purposes. The prostheses comprise a scaffold which is implantable within a body lumen and a substance reservoir present over at least a portion of the scaffold. Usually, a rate-controlling element will be formed over the substance-containing reservoir to provide for a number of different substance release characteristics.