In a radical new approach to treat cocaine addition, researchers at America’s Mayo Clinic are seeking approval for the first-in-human studies of a single-dose gene therapy.
Research published in Human Gene Therapy has demonstrated the successful delivery of AAV8-hCocH, an adeno-associated viral vector encoding a modified plasma enzyme that metabolises cocaine into harmless by-products.
To assess the safety of AAV8-hCocH, studies were carried out in cocaine-experienced and cocaine-naive mice at doses of 5E12 and 5E13 vector genomes/kg.
Results showed total lack of viral vector-related adverse effects in all tests performed. Instead, mice given one injection of AAV8-hCocH and regular daily injections of cocaine had far less tissue pathology than cocaine-injected mice with no vector treatment.
Biodistribution analysis showed the vector located almost exclusively in the liver, suggesting that a liver-directed AAV8-hCocH gene transfer at reasonable dosage is safe, well tolerated and effective.
The authors say the data provide a strong basis to conclude that a cocaine-hydrolysing enzyme in adequate dose can drive a large drop in ‘reward value’ of a given cocaine dose.
Based on these positive findings, the US Food and Drug Administration (FDA) has granted authorisation for a proposed clinical trial to proceed to patient accrual.