Several epothilones and their synthetic analogs have been developed, each with unique properties. The most notable include: 1. Epothilone A and B: The naturally occurring forms, isolated from the myxobacterium. 2. Ixabepilone: A semisynthetic analog approved by the FDA for the treatment of metastatic or locally advanced breast cancer. It has shown efficacy where taxanes have failed. 3. Epothilone D (KOS-862): Another synthetic derivative that is currently being investigated in clinical trials.
