A semisynthetic, second-generation taxane derivative with potential antineoplastic activity. Ortataxel binds to and stabilizes tubulin molecules, thereby interfering with the dynamics of microtubule assembly/disassembly. This results in the inhibition of cell division and cellular proliferation. As it represents a poor substrate for P-glycoprotein (P-gp), multi-drug resistance protein (MRP-1) and breast cancer resistance protein (BCRP) mediated efflux, ortataxel modulates multi-drug resistance mechanisms and may be useful for treating multi-drug resistant tumors that express Pgp, MRP-1 and BCRP.