A composition for delivering a tumor therapeutic agent to a patient includes a fast-release formulation of a tumor apoptosis inducing agent, a slow-release formulation of a tumor therapeutic agent, and a pharmaceutically acceptable carrier. An apoptosis-inducing agent in a pharmaceutically acceptable carrier may be administered before or concomitantly therewith. Nanoparticles or microparticles (e.g., cross-linked gelatin) of the therapeutic agent (e.g., paclitaxel) also may be used. The nanoparticles or microparticles may be coated with a bioadhesive coating. Microspheres that agglomerated to block the entrance of the lymphatic ducts of the bladder to retard clearance of the microparticles through the lymphatic system also may be employed. This invention also uses drug-loaded gelatin and poly(lactide-co-glycolide) (PLGA) nanoparticles and microparticles to target drug delivery to tumors in the peritoneal cavity, bladder tissues, and kidneys.