Sagopilone (ZK-EPO): from a natural product to a fully synthetic clinical development candidate.

BACKGROUND: Tubulin is among the most established and clinically validated targets in oncology. The taxanes, paclitaxel and docetaxel, stabilize microtubules and have shown significant clinical activity, but factors such as the development of resistance can limit their clinical use. The epothilones are a novel class of natural microtubule-stabilizing products with potential activity in an expanded spectrum of tumour indications.
OBJECTIVE: In an extensive lead optimization programme, we selected sagopilone from 350 compounds produced by total synthesis because of its combination of potent activity and good tolerability in tumour models. It is the first fully synthetic epothilone in clinical development.
METHODS: Here we review the directed optimization of the natural product epothilone B to produce sagopilone, along with its mechanism of action, preclinical data and emerging clinical results. RESULTS/
CONCLUSIONS: We show how this optimization process translated into superior preclinical activity, coupled with a favourable tolerability profile. Activity has been determined in a number of animal models, including those from tumours resistant to other systemic treatments. The approach used to develop sagopilone may become more common as structure-driven research is increasingly employed to exploit the enormous potential of natural products, in parallel with other targeted approaches, heralding a new era of anticancer therapy.