Drug Companies Search for Blockbuster Pain Medications

WASHINGTON, May 12, 2005 — -- Scientists are looking at everything -- from poisonous puffer fish to spicy chili peppers -- to find the next big painkiller.

Eli Lilly and dozens of other pharmaceutical companies employ drug hunting teams specifically focused on pain.

"We're basically trying to understand what are the pathways, what are the targets for new drugs in the central nervous system, in the pain pathways," said Dr. Darryle Schoepp, Eli Lilly's vice president of neuroscience discovery research.

Pathways are the route pain travels from one nerve to the next, via electrical impulses, all the way to the brain.

WEX Pharmaceuticals Inc., a Canadian drug company, is trying a novel approach -- a drug derived from the puffer fish. While its poison can paralyze a person in minutes, tests show tiny amounts of the fish's toxin can actually relieve pain in cancer patients.

The toxin works by blocking sodium, which is needed for nerves to transmit signals to one another.

"We have shown that patients have complete pain relief, some of the cases up to 15 days," said Donna Shum, chief operating officer of Wex Pharmaceuticals.

Meanwhile, GlaxoSmithKline has determined the sensor in the human body that reacts to the hot chili pepper also plays a role in pain. The drug company is testing a compound to disable that sensor.

Improving Old Drugs

In addition to finding new drugs, scientists are trying to improve old ones.

Opiates, like OxyContin, relieve severe pain but are highly addictive. Pain Therapeutics, a California-based company that develops medications used in pain management, is testing a drug that combines derivatives from the opium plant with another medication that blocks addiction.

"To the extent that we can provide sufficient, adequate pain relief without making them feel hooked on our drug, that is a huge advantage for pain relief," said Remi Barbier, president and chief executive officer of Pain Therapeutics.

In an effort to develop effective drugs, scientists can now use sophisticated imaging to measure the brain's reaction to pain and pain medications.

"You have this objective map, essentially, or read-out of how each drug works," said Dr. David Borsook of McLean Hospital at the Harvard Medical School, which developed the technique called functional magnetic resonance imaging.

A blockbuster drug could mean billions for a pharmaceutical company and relief for patients. Drug companies are exploring hundreds of possible pain drugs, but unfortunately for pain sufferers, most are years away from being released to the public.

ABC News' Lisa Stark filed this report for "World News Tonight."