A synthetic form of a sea-snail venom was approved yesterday by the Food and Drug Administration as a novel approach to treating severe, chronic pain. The drug, called Prialt...
WASHINGTON — A synthetic form of a sea-snail venom was approved yesterday by the Food and Drug Administration as a novel approach to treating severe, chronic pain.
The drug, called Prialt, was approved for hard-to-treat pain associated with cancer, AIDS and neuropathies. Based on a compound found in the poison of the South Pacific cone snail, it controls pain in an entirely new way — by blocking the calcium channels in nerve cells that transmit pain signals — and may have broad implications for pain management.
Because it is as much as 1,000 times more powerful than morphine, it is considered a last resort for long-suffering patients, rather than a first-line pain medication.
“This drug is very exciting because it’s a very potent analgesic but isn’t a narcotic,” said Richard Rauck, of Wake Forest University Medical Center and the Carolinas Pain Institute. Rauck, an investigator for one of the clinical trials that led to yesterday’s FDA approval, said he found the drug to be “effective in almost all types of chronic pain it’s been studied in.”
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What will limit the use of Prialt is that it cannot be taken in pill form. It must be delivered directly into the fluid surrounding the spinal cord, which carries it to the brain without affecting other organs. Because it is so potent, tiny amounts of the drug could be dangerous to the heart and possibly other organs.
“This drug is for patients in chronic and severe pain who are not getting substantial and meaningful relief with oral opiates or are having unacceptable side effects with them,” said Robert Meyer, director of the FDA’s Office of Drug Evaluation II.
Nonetheless, Lars Ekman, president of Élan Inc. of Ireland, the drug’s maker, said up to 100,000 people in the United States might be helped by the drug.
About 50,000 patients already use devices that pump morphine directly into the spinal column, he said, and many of them may want to try Prialt because opioids can gradually lose their effectiveness. In addition, many patients in severe pain who take pain pills may want to try the spinal-cord route if the drug involved is not an opioid, he said.
“There are thousands of people out there who have pain like a bad toothache all day and night, week after week,” Ekman said. “Many of these people have tried morphine, and it either didn’t work or made them unable to function.”
Prialt is a synthetic form of the venom that the Conus magus snail, which lives in tropical saltwater shallows, uses to stun passing prey.
Prialt, expected to reach the market next month, will come with a “black box” warning — the FDA’s strongest warning — regarding its risks, which include hallucinations and even psychosis.
Despite Prialt’s limitations, Mary Pat Aardrup, executive director of the National Pain Foundation, a nonprofit education group, called it a “red-letter day” for pain patients. “To have another pain drug in an entirely new class is very exciting and very hopeful.”