WITHIN two years, cocaine addicts desperate to kick the habit could take part in a pioneering trial of a gene therapy that gives them extra copies of a gene primed to mop up the drug.
The therapy will be combined with a new vaccine that stops cocaine reaching the brain. Former addicts who get no kick from the drug will be less likely to get hooked again if they relapse.
The gene in question codes for a fast-acting version of the enzyme butyrylcholinesterase, which destroys cocaine. Giving multiple copies of the gene to addicts would prevent them getting high while they try to quit.
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A single relapse within a year of giving up cocaine prevents 90 per cent of addicts staying clean, says of the Mayo Clinic in Rochester, Minnesota.
If Brimijoin鈥檚 experiments in rats are anything to go by the therapy should be effective 鈥� rats refrained from seeking out cocaine for up to a year after gene therapy.
Brimijoin uses harmless cold-related viruses to get the gene into rat cells. The gene is taken up mostly by liver cells, where it produces high quantities of the enzyme for at least a year.
Injecting the enzyme directly into addicts wouldn鈥檛 be effective since it would rapidly disappear and need to be topped up.
鈥淎 long-term mode of delivery had the potential to make most difference,鈥� Brimijoin says. But he was concerned that even multiple copies of the gene for the enzyme might not act fast enough to prevent an addict getting a high if they succumbed to temptation.
So he has teamed up with researchers led by Thomas Kosten at Baylor College of Medicine in Houston, Texas, who have created a vaccine that generates antibodies that bind to cocaine almost immediately, preventing the drug from entering the brain. Once the antibodies intercept the early hit, the enzyme can mop up any remaining cocaine.
The plan is to run trials of the combined approach within the next couple of years.