Epothilone B (EPO 906) is a compound isolated from the myxobacterium Sorangium cellulosum. Similar to paclitaxel, patupilone induces microtubule polymerization and stabilizes microtubules against depolymerization conditions. In addition to promoting tubulin polymerization and stabilization of microtubules, this agent is cytotoxic for cells overexpressing P-glycoprotein, a characteristic that distinguishes it from the taxanes. Patupilone may cause complete cell-cycle arrest.

Ixabepilone (Azaepothilone B) is an orally bioavailable microtubule inhibitor. It binds to tubulin and promotes tubulin polymerization and microtubule stabilization, thereby arresting cells in the G2-M phase of the cell cycle and inducing tumor cell apoptosis.

BMS 310705 (21-Aminoepothilone B), an Epothilone B analog, specifically targets malignancies including ovarian, renal, bladder, and lung carcinoma. It significantly induces apoptosis through the mitochondrial-mediated pathway [1].

Iso-Fludelone is the third-generation epothilone B analogue with potential anti-mitotic and antineoplastic activites. Iso-fludelone binds to tubulin and induces microtubule polymerization and stabilizes microtubules against depolymerization, which may result in the inhibition of cell division, the induction of G2/M arrest, and apoptosis. Compared to other generations of epothilones, iso-fludelone exhibits increased stability, water solubility, potency, duration of action, tumor penetration as well as reduced toxicity. In addition, this agent is a not a substrate of the P-glycoprotein (P-gp), a multidrug resistance pump often overexpressed in cancer cells. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus).