Cone snail proving to be companies' best friend

The cone snail, a marine snail from the Great Barrier Reef, is proving to be a vaulable ally in pain management drug research.

Early release of data from a clinical trial of a drug isolated from the cone snail has shown promising results for Amrad Corporation.

The drug, AM336, appears to have beneficial results in cancer patients with severe chronic pain, according to the company's managing director, Dr Sandra Webb.

"The most exciting thing for us was that patients wanted to keep taking the drug," she said.

The drug was administered to patients over a period of 12 days to investigate safety and tolerance to different doses.

Under the Federal government's Special Access Scheme, patients are allowed to continue receiving unapproved drugs under the supervision of the investigating doctor. The patients will continue to be monitored while taking the AM336, providing further information to the clinical team.

Many cancer patients struggle with severe chronic pain that has traditionally been treated with narcotic drugs such as morphine. These drugs can have severe side-effects and often patients become resistant to the drugs. The potential market size for drugs to treat severe pain is US$400 million.

AM336 is a synthetic version of CVID, a calcium channel blocker isolated from the cone snail Conus catus. It is administered intrathecally, or directly into the patient's cerebro-spinal fluid, where it blocks pain signals in the spine. CVID was discovered at University of Queensland through a collaborative research program.

Amrad has exclusive worldwide rights to develop the compound.

The Phase I/II clinical trial was not scheduled for completion until later this year, but increased patient recruitment has allowed the trial to finish early.

Full analysis of the results will be available in a couple of months, according to Amrad's medical director, Dr David Crump. The early completion of the trial means that Amrad is able to begin a full phase II study later this year. This study will look more closely at the efficacy of AM336 in patients with chronic pain.

Amrad also has plans to meet with the US Food and Drug Administration in March to talk about the development pathway of AM336.

Dr Webb said that the agency was a valuable source of feedback and had the knowledge and resources to assist Amrad in determining how to proceed with its clinical development.

Another Australian company - Xenome, based in Brisbane - is also developing pain drugs based on compounds isolated from the venom of cone snail species, but has not started clinical trials in people.

Xenome yesterday announced that it had begun pre-clinical testing of a new molecule, derived from cone snail venom, to treat neuropathic and inflammatory pain. Dr Roger Drinkwater, Xenome's head of research, said the molecule had proved to be effective in animal trials.