Efficacy and safety of ixabepilone, a novel epothilone analogue.

The epothilones and their analogues are a new class of anticancer agents derived from the fermentation of myxobacterium Sorangium cellulosum. These compounds have some similarities to taxanes in targeting and stabilizing microtubules, but they also have important differences. Among the epothilone family, ixabepilone has emerged to be a semisynthetic epothilone analogue of interest. Ixabepilone has demonstrated consistent preclinical activity and seems active against various taxane-sensible and taxane-resistant cell lines, including those with overexpression of multidrug resistance and with mutations in the beta-tubulin gene. The interest of this ixabepilone has been confirmed clinically. Phase II clinical studies have demonstrated high activity in patients with taxane-resistant metastatic breast cancer and in patients with other chemotherapy-resistant tumor types.