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Christine Soares, Kerry S. Matz Popular Science
A race
to find the next wonder drug is taking place at the bottom
of the ocean and a snail is in the lead.
Elan
Pharmaceuticals—one of the many pharmaceutical companies
probing sponges, corals, microbes, and other denizens of
the sea—will likely get approval from the Food &
Drug Administration to market ziconotide, a powerful painkiller
that the company developed from the venom of the Conus magus
snail. Initially, ziconotide will be targeted to patients
suffering severe chronic pain—a population of more
than 1 million Americans alone. In clinical trials, it proved
1,000 times more potent than morphine, but with negligible
side effects, and patients never developed a tolerance.
Ziconotide’s
secret: It blocks communication between pain-sensing nerve
cells and the spinal cord neurons that relay those signals
to the brain. Such exquisite precision is the human chemist’s
Holy Grail, and the snail’s way of overcoming its speed
handicap. "Because it is problematic for an animal
that can’t swim to capture fish, snails have clever
strategies," explains University of Utah biologist
Baldomero Olivera, who first isolated the venom component
that became ziconotide. The snail paralyzes its prey by
injecting venom with a harpoon-like organ before reeling
it in.
The
drug is a synthetic version of just one peptide from among
more than 100, which together make Conus magus venom a highly
toxic cocktail. "They have 55 million years of natural
selection. That leads to a lot of sophistication."
The
Cone snail family—which includes more than 500 distinct
species, each of which produces a unique venom—is sure
to yield additional new drugs. Ziconotide is already in
trials for broader indications. Australian researchers are
reportedly developing a painkiller that is even more powerful
than ziconotide, and a Utah biotech company expects to begin
trials of an anti-epileptic this year.
A powerful new painkiller comes from
venom that an Indo-Pacific cone snail uses to paralyze its
prey.
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