1,000 times more potent than morphine

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The deadly sea snail venom that will take away your pain

By Nigel Hawkes, Health Editor

 

 

 

 

 

 

A NEW painkiller based on the venom of a sea snail will be available

in Britain from today.

Prialt, or ziconotide, is the result of more than 20 years' research

by a scientist born in the Philippines, Baldomera Olivera, who is a professor at

the University of Utah.

 

It is 1,000 times more potent than morphine but, unlike that drug,

is not addictive. It is aimed at people suffering from severe, chronic pain who

would normally require morphine.

 

 

 

Given by injection into the fluid around the spine, it is the first

non-opioid painkiller using this method of administration to be approved in

Europe.

 

Chronic pain is a common problem, surveys indicating that it is

suffered by as many as one in seven people. Back pain and arthritis are the

commonest causes, with headache and injury also affecting many people.

 

Painkillers given by mouth, such as paracetamol or ibuprofen, are

the first resort. But those whose pain persists may be treated with painkillers

injected into the spinal fluid, using a pump worn by the patient.

 

Prialt, made by Eisai, is designed for these extreme cases. It is a

synthetic version of the venom used by Conus magus, the Magician's Cone Snail,

to hunt prey.

 

The two-inch snail, native to coral reefs in the Pacific, hunts by

shooting out a thin wormlike tube into fish swimming by. The venom is injected

into the fish, which are paralysed and can be swallowed whole. Professor Olivera

used to collect the shells of the snails as a boy, then went on to study them.

 

The venom was discovered by a teenager, Michael McIntosh, who

started to help with the research soon after leaving school. Now, 25 years

later, he is a research psychiatrist at the University of Utah and still works

with Professor Olivera.

 

Together they analysed the venom and identified one peptide (a short

chain of amino acids) that stopped nerve cells sending signals to the brain. It

acts by blocking the calcium channels on the nerves that transmit pain signals.

Once the channels are blocked, calcium cannot enter the cells, and pain signals

are blocked from travelling between nerve cells.

 

Prialt was licensed in Europe by Elan, which sold it to Eisai, a

Japanese pharmaceutical company best known in Britain for the Alzheimer drug

Aricept. There may be more to come from the cone snail, Professor Olivera

believes. There are 500 different types, and each produces as many as 100 toxins

in its venom. He hopes that they will provide compounds to treat a wide range of

conditions, from Parkinson's disease to depression.