Immunotherapy: Are Vaccines the new future for Drug Addiction Treatment?

Vedika Puri

According to the 2017 World Drug Report, an estimated 271 million people worldwide had used drugs at least once in 2016 and some 35 million people suffered from a drug use disorder. These people demand immediate care and rehabilitation but only 1 in every 7 receives the required treatment (UNODC 2019). Treatment options for these people include behavioural interventions and pharmacological cures and despite these being the current most effective treatment approaches for drug addiction, their success rates are far from optimal (Montoya 2008). 

According to the NSDUH, only 10% of those treated for substance use disorders are considered recovered (Montoya 2008). This is mainly because drug addiction is a chronic, relapsing disease that presents a heavy burden to the individual and society. Repeated drug use can change the brain so that an addicted person’s self-control and ability to resist cravings are affected. Recent statistics show that more than 85% of individuals relapse and return to drug use after treatment. Although considered a part of recovery, relapse can be deadly because of the high risk of overdose (NIDA 2018).

           With a growing prevalence in substance abuse and with relapse being the main hurdle to recovery, extensive medical and psychosocial consequences are at stake. Additionally, the unsatisfactory effects of the current treatment approaches reinforce a need for new effective methods and therapeutic hypotheses. 

            In such a situation, immunotherapy presents itself as a very promising new therapeutic strategy in the treatment of psychoactive drug addiction. Until now researchers have succeeded in developing vaccines and/or antibodies against heroin, cocaine, methamphetamine, nicotine and phencyclidine. At a stage of research, Phase III clinical trials are ongoing, but preclinical studies have confirmed immunotherapy’s effectiveness for drug addiction treatment (Montoya 2008).

            There are two forms of immunotherapies - vaccines (active immunization) used for reducing relapse in addicted patients and monoclonal antibodies (passive immunization) used for treating drug overdoses (Kosten 2005). The research assumes that immunotherapy can identify the addictive substances as antigens and produce antibodies against them. Once an antibody binds with a psychoactive substance, they prevent them from passing through the blood/brain barrier and thereby thwart their harmful effect on the brain. Thus, they can provide immediate protection against overdoses and also can slowly extinguish addiction using the lack of euphoric effect to sever the cycle between drug intake and reward (Kaszubska 2015). 

            The main advantage of Immunotherapy over pharmacotherapy is the lack of adverse effects on the CNS. The available data indicates that antidrug antibodies present a favorable safety profile. Indeed, anti-methamphetamine mAb doses of up to 1.0 g/kg body weight have been safely administered to rats without any harmful effects (Kosten 2005). The vaccines also offer advantages over medications in terms of cost, length of effect and a lack of addiction liability (Kaszubska 2015).

            The potential clinical applications of immunotherapy include using monoclonal antibodies (mAb) for treatment of acute or chronic drug overdoses and for improving health. In a rat overdose model, an anti-methamphetamine mAb decreased drug distribution to the brain by >60%. In another study, a single mouse anti-phencyclidine mAb dose profoundly reduced pharmacological effects and significantly improved phencyclidine-induced adverse health effects (Kosten 2005). 

           Secondly, the vaccines reduce relapse by diminishing the reinforcing effect of drugs. In a 2006 study,vaccinated rats produced a high level of antibodies against heroin and morphine that sufficiently reduced self-administration of heroin in heroin-addicted rats. By reducing the “high”, vaccines break the addiction cycle and help treat addiction (Kaszubska 2015).

           Thirdly, vaccines can be used as preventive tools to stop the development of addiction in people who have not experimented or are beginning to experiment with addictive drugs such as foetuses of drug–abusing mothers or adolescents. However, this application does have certain ethical complexities and cannot offer long-term protection (Kosten 2005).

           Therefore, these benefits of immunotherapy are interlaced with certain problems*. One of them is controlling the level of antibodies due to variability between subjects. Second, there is a risk of overdose as vaccines do not reduce cravings. Since vaccines prevent the positive reinforcement of drugs, some patients could erroneously seek higher doses of psychoactive substances to get "high" (Kaszubska 2015). 

           Subsequently, vaccination can only be used for those who have a strong motivation to free themselves from drug dependency while for the unwilling patients it only serves as a psychotherapy and pharmacotherapy support. Thus, even though immunotherapy presents progress in the addiction treatment, they are not a panacea for solving all addiction related problems (Montoya 2008). 

            From the above discussion, we undoubtedly conclude that immunotherapy can play a critical role in overdose and relapse prevention during drug addiction treatment. It does have certain limitations, the foremost being its inability to reduce cravings. However, immunotherapy, if combined with other medications and behavioural interventions, can overcome its limitations and hold immense potential. Thus, immunotherapy presents a highly effective, viable and rapid treatment promise for existing and future addiction problems.

Works Cited

American Addiction Centers Editorial Staff. (2019, September 6). Drug Relapse: Drug Addiction Relapse Statistics & Prevention. Retrieved October 26, 2019, from https://drugabuse.com/drug-relapse/.

Kantak, K. M. (2003). Vaccines Against Drugs of Abuse A Viable Treatment Option? Adis, 341–352.

Kosten, T. (2005). Immunotherapy for the treatment of drug abuse. Elsevier, 77–85. doi: doi:10.1016/j.pharmthera.2005.06.009

Montoya, I. (2008). Immunotherapies for drug addictions. Retrieved October 26, 2019, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633931/.

National Institute on Drug Abuse. (n.d.). Treatment and Recovery. Retrieved October 26, 2019, from https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/treatment-recovery.

United Nations Office on Drugs and Crime (UNODC). (2019). Global Overview of Drug Demand and Supply: World Drug Report 2019. Global Overview of Drug Demand and Supply: World Drug Report 2019 (pp. 1–19). Vienna.

Vchangul. (n.d.). United Nations Office on Drugs and Crime. Retrieved October 26, 2019, from https://www.unodc.org/unodc/en/frontpage/2019/June/world-drug-report-2019_-35-million-people-worldwide-suffer-from-drug-use-disorders-while-only-1-in-7-people-receive-treatment.html.

Zalewska-Kaszubska, J. (2015). Is immunotherapy an opportunity for effective treatment of drug addiction? Elsevier, 1–7. doi: http://dx.doi.org/10.1016/j.vaccine.2015.09.079

*No empirical data can be provided for the limitations of immunotherapy as the Phase 3 Clinical Trials are ongoing.