Heroin vaccine close to human trials

Scientists from the US say they have achieved a major milestone toward designing a safe vaccine to both treat heroin addiction and block lethal overdose of the drug.

Their research, published in the journal Molecular Pharmaceuticals, shows how a new anti-heroin formulation that is safe in animal models remains stable at room temperature for at least 30 days. As a result, the vaccine is close to being ready for human testing.

Dr Candy S. Hwang, first author of the study and a research associate at The Scripps Research Institute said: “Our goal was to prepare a vaccine that could be advanced to clinical trials. As such, we were looking for the best combination of hapten ­– the heroin molecule – carrier protein and adjuvant to keep the vaccine both stable for transport and storage but still efficacious.”

The first formulation of the heroin vaccine was developed in 2013 and has been shown to be effective and safe in both mouse and non-human primate models. The vaccine stimulates antibodies to recognise and bind to heroin molecules, blocking the drug from reaching the brain. Researchers believe that blocking the high of heroin will help eliminate the motivation for many recovering addicts to relapse into drug use.

The heroin molecule does not naturally prompt an antibody response, so researchers attach it to a carrier protein that alerts the immune system to start making antibodies. For the recent study, the researchers investigated how 20 different carrier protein/adjuvant combinations worked, including shelf stability based on temperature and storage time and whether the formulation was a liquid or powder.

Their experiments in rodent models showed that the best vaccine formulation contained a carrier protein called tetanus toxoid (TT) and adjuvants called alum and CpG ODN.

The next step is to find a producer to make the vaccine on a large scale.