Gene therapy could treat cocaine addiction in the futurePublished: February 11, 2020
Scientists at the Mayo Clinic have provided preclinical evidence to demonstrate the potential of gene therapy in treating cocaine addiction.
Cocaine addiction poses a serious health concern on the affected individuals as well as the broader society and according to a 2014 NIH report, there were an estimated 1.5 million cocaine users in US alone.
Cocaine is one of the most addictive drugs because of its immediate and powerful rewarding effects. Cocaine-dependent individuals experience difficulty in abstaining due to cognitive impairment from repeated cocaine use, strong use–related social and environmental cues, and high levels of life stress. Presently, there are no medications approved by the FDA to treat cocaine addiction.
In the present study published in Human Gene Therapy, Dr Stephen Brimijoin and team at the Mayo Clinic tested the potential of gene therapy in treating cocaine addiction. The group tested if gene therapy could make cocaine use less rewarding and thus could help reduce the risk of relapse for treatment-seeking cocaine users.
To test this, the team used a viral vector-based gene therapy approach, where an adeno-associated viral vector encoding a modified plasma enzyme (AAV8-hCocH) that metabolizes cocaine into harmless by-products was administered into cocaine-experienced and cocaine-naive mice. CocH when injected into the bloodstream, breaks down cocaine fast enough before the user can experience the pleasurable effects. This makes a dose of cocaine less rewarding and thus makes it easier to stop using cocaine.
Results showed AAV8-hCocH was safe and well tolerated in normal mice and in cocaine-exposed mice. Mice which were 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.
Findings from the study thus demonstrate gene transfer therapy as a radically new approach to treat compulsive cocaine abuse. Based on the positive findings from this study, the FDA has approved the team’s investigational new drug (IND) application and therefore a human Phase 1/2 clinical trial is due to begin soon in patients with cocaine addiction.
Source: Systemic Safety of a Recombinant AAV8 Vector for Human Cocaine Hydrolase Gene Therapy: A Good Laboratory Practice Preclinical Study in Mice. Chen P et al., Human Gene Therapy, January 2020. DOI