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Last Updated: Monday, 10 July 2006, 14:06 GMT 15:06 UK
Snail venom painkiller launched
Cone snail (J Bingham)
Cone snails "harpoon" passing prey
A drug that harnesses the power of deadly sea snail venom has been launched in Britain.

Prialt is a strong painkiller designed for patients suffering from chronic pain who cannot tolerate treatments like morphine.

It is based on a toxin produced by a the magician's cone snail.

The snail uses venom to paralyze passing fish, but scientists found chemicals in the poison could also block pain signals in the human brain.

Conus magus, or the magician's cone snail, is one of about 500 species of cone snail.

It is found in tropical waters such as the Great Barrier Reef and in the South Pacific.

These snails are nature's pharmaceutical drug designers
Dr Jon-Paul Bingham

It hunts by harpooning its prey and injecting it with venom before swallowing now-immobile fish whole.

About 25 years ago, scientists at the University of Utah, in the US, managed to isolate a molecule from the venom that also had painkilling properties in humans.

The molecule works by preventing nerve cells from sending pain signals to the brain.

Extreme pain

Now researchers have created a synthetic version of the compound with similar pain-killing effects, and it forms the basis of this new drug, Prialt.

Prialt is injected directly into the fluid surrounding the spinal cord through a small pump worn by the patient.

It is to be used for those suffering extreme chronic pain - such as cancer patients - for whom morphine is ineffective or unsuitable.

It was approved for use in the US by the Food and Drug Administration in 2004, and marketing authorisation was granted by the European Union in 2005. It is the first injected non-opioid painkiller to be used in Europe.

Prialt is manufactured by Japanese pharmaceutical company Eisai Co Ltd.

Many scientists think cone snails may yield more medicines - and teams are looking at the venoms in different species to see if they can isolate compounds to treat diseases including Alzheimer's disease, Parkinson's disease and epilepsy.

But the creatures are under threat - their beautiful shells make them a prize-target for shell collectors.

Dr Jon-Paul Bingham, a neuroscientist from Clarkson University in New York, said the drug had been well received in the US and he had great hope for finding even more cone snail venom-based compounds in the future.

He said: "These snails are nature's pharmaceutical drug designers. And with Prialt we are really only touching the surface tip of the iceberg of what they can do.

"We estimate there are 75,000 compounds out there that could have some potential use in all kinds of applications.

"The issue is that there are only a few of us who have access to the material. The species are very rare, so we have to do it in a very bio-sustainable manner."

Venomous snails aid medical science
28 Mar 06 |  Science/Nature
Drug-hope snails imperilled
20 Oct 03 |  Science/Nature

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