Chemical weapons vaccine enters clinical trials

A vaccine that protects against the effects of nerve agents often used in chemical weapons is ready to be tested on human volunteers, according to developer Baxter Healthcare.

The 'BioScavenger' vaccine could prevent and possibly treat the effects of exposure to organophosphorus nerve agents such as Sarin, Soman and VX. The Phase I clinical trial will be managed by the DynPort Vaccine Company (DVC), part of information technology service provider Computer Sciences.

"Confirming the safety of this product in humans is a crucial step toward an FDA-licensed chemical nerve agent prophylactic," said Dr Robert House, chief scientific officer of DVC.

VX can kill within minutes at levels as low as 50mg. According to the United Nations Special Commission on Iraq, former dictator Saddam Hussein ordered missiles loaded with the nerve agent to be manufactured.

The molecules that make up organophosphorus nerve agents permanently attach themselves to enzymes in the blood and tissue, preventing those enzymes from working. This stops certain neurons from being able to return to their resting state and leads to a build up in neurotransmitter levels. Depending on where the agent is absorbed by the body, this can cause pain, nausea, loss of consciousness, convulsions and ultimately death.

The vaccine consists of plasma-derived butyrylcholinesterase, one of the enzymes attacked by nerve agents. By replacing the enzyme, the vaccine could prevent or lessen the effects of exposure.

DVC is conducting the trial as part of a contract awarded by the US Department of Defense Medical Identification and Treatment Systems (MITS). The trial will test the safety of the vaccine on 40 healthy volunteers aged between 18 and 55.

If the trials prove successful, Baxter Healthcare will hold the FDA license and have responsibility to supply stockpile orders.