Ixabepilone is an antineoplastic agent, epothilone and mitotic inhibitor that is FDA approved for the treatment of patients with metastatic or locally advanced breast cancer resistant to treatment with an anthracycline and a taxane, or whose cancer is taxane resistant and for whom further anthracycline therapy is contraindicated. Ixabepilone binds directly to beta-tubulin subunits on microtubules, leading to suppression of microtubule dynamics. Ixabepilone suppresses the dynamic instability of alpha-beta-II and alpha-beta-III microtubules. The most common adverse reactions (≥20%) are peripheral sensory neuropathy, fatigue/asthenia, myalgia/arthralgia, alopecia, nausea, vomiting, stomatitis/mucositis, diarrhea, and musculoskeletal pain. Inhibitors of CYP3A4 may increase plasma concentrations of ixabepilone.

Patupilone 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. Epothilone B may cause complete cell-cycle arrest. Patupilone failed a phase III trial for ovarian cancer in 2010.