Novel encapsulated umirolimus and umirolimus polymer conjugate formulations having enhanced permeability and retention at tumor sites. Also provided are methods for treating cancer by administering the umirolimus formulations.本發明提供了具有增強的滲透性和在腫瘤部位滯留的新型包封的烏米莫司(umirolimus)和烏米莫司聚合物綴合物製劑。還提供了通過施用所述烏米莫司製劑用於治療癌症的方法。