Xenova's anti-cocaine drug in new tests

Xenova, the biotechnology group, yesterday began the second phase of testing a breakthrough drug for fighting cocaine addiction.

The drug, which is a cocaine derivative, aims to build an antibody response against cocaine that neutralises its effect on the brain. If the addict relapses, the cocaine will bind to antibodies in the blood stream and interfere with the ability of the cocaine to enter the brain and produce stimulating effects. Addicts will no longer get the high that leads to the dependency.

TA-CD is the first vaccine to be developed with the goal of assisting cocaine abusers in their attempt to quit. "There is a substantial need for new approaches to help drug addicts overcome their habit," said David Oxlade, Xenova's chief executive. "TA-CD has made promising progress in earlier clinical studies and this additional trial is designed to show for the first time whether addicts' behaviour can be altered."

The 10-patient trial is being conducted in the US and is being part funded by its National Institute on Drug Abuse. The volunteers are cocaine-dependents who are not seeking to quit, to make it harder for the treatment to work. The trial is designed to evaluate the effect of TA-CD on behavioural changes associated with taking cocaine and the volunteers will undergo psychological as well as physiological assessments whilst cocaine is administered under laboratory conditions.

There are two million regular cocaine users in the US, 900,000 of which seek treatment for their habit every year. A positive outcome from the trial is likely to spark more Government interest, and could lead to a number of licensing deals.

Analysts, however, believe the drug is still a long way from launch and some are not expecting TA-CD to produce revenues for Xenova until 2009. The group revealed in February that it had to stop recruiting patients for final-stage trials of its leading cancer drug, Tariquidar, on fears that the drug was not safe enough to use. The news sent shares down 38 per cent to a record low. The company hopes it can restart recruitment for its Tariquidar trials next month. Shares in Xenova closed up yesterday nearly 9 per cent at 12.25p.