Conus

Bert Myers/Photo Researchers Inc.

This past December, the US Food and Drug Administration approved Prialt, Elan Corporation's synthetic version of a peptide from the venomous sea snail Conus magus. The drug, ziconotide, is the first of its kind and appears to alleviate severe pain by blocking N-type Ca⁺ channels.

Ziconotide is designed from one of about 100 pharmacologically active compounds in C. magus. And this undersea combinatorial chemist is only one of approximately 500 Conus species. Research on several of these peptides has turned up compounds with different modes of action, making them potentially useful in treating other types of pain.

But how these peptides relieve pain is still largely unclear. Moreover, ziconotide can only be delivered intrathecally to chronic pain patients who have no other options for relief and can cause cognitive impairment and hallucinations. Nevertheless, hope remains that the search for other peptides from Conus...