In an embodiment, the current invention is a composition for oral or parenteral administrable taxane to treat cancer in human patients, comprising orally or parenterally co-administering to said patient a taxane comprising a derivative, an analog or a prodrug of paclitaxel or docetaxel, and bioavailability and efficacy enhancing agent comprising a piperlongumine. The present invention relates in its principal aspect to the oral or parenteral administration of one or a combination of taxanes to human patients suffering from cancer. In another embodiment, the current invention is a method of increasing the bioavailability of taxanes, which are poorly absorbed or not absorbed at all from the gastrointestinal tract or gut, by pre-administering and/or simultaneously administering to a human subject orally or parenterally one or a combination of agents (“enhancing agents”) effective in enhancing bioavailability by inhibiting CYP3A4 enzyme. In yet another embodiment, the current invention is a method for enhancing the cytotoxicity of taxanes with synergistic interaction in variety to cancer cells.
