So it looks like the FDA is giving Eisai's (OTCPK:ESALY) oncology drug Eribulin (E7389) a priority review. The company had hoped to get it reviewed three years ago, but the FDA told them to get back into the clinic and collect more data.
The compound is being reviewed for advanced breast cancer, and the earlier clinical data looked pretty good. (Head and neck tumors, on the other hand, didn't show much of a response). It binds to yet another site on tubulin (a popular site for various oncology agents), but in a rather complicated fashion that differs from the other agents in this category.
The compound is remarkable mainly for its brutal structural complexity, and for the fact that it's being made synthetically. It looks like a natural product, for sure, but it's actually a modified version of the right-hand side of halichondrin B, whose structure is still more horrific. Kishi's group at Harvard synthesized that beast back in 1992, and that work was the foundation of the synthesis of Eribulin. I don't think this is necessarily going to spark a renaissance of Big Natural Product Analog Synthesis inside the pharma labs, but it's quite a story. Here's hoping it has a good ending - we should know in September.