Preclinical evaluation of new taxoids.

Paclitaxel and docetaxel are two key molecules in the treatment of a variety of cancers with major impact in the treatment of breast, lung and ovarian cancers. A number of taxoids have then been synthesized in an effort to improve some of the features of the existing drugs. Although the literature is still scant of preclinical data due to the highly competitive field, several compounds are already in clinical trials. Most of these will be reviewed and have, either improved water solubility or reduced cross-resistance with marketed taxoids or reduced interaction with P-glycoprotein. In addition, the reduced recognition of several compounds by multi-drug-resistance related transport systems has yielded some orally bioavailable compounds with marked in vivo antitumor activity. It is likely that these additional properties should lead to an expanded spectrum of clinical activity compared to that of clinically available taxoids.