The continuing search for an addiction vaccine

Vaccines as Immunotherapies for Substance Use Disorders

Substance use disorders (SUD) present a worldwide challenge with few effective therapies except for the relative efficacy of opioid pharmacotherapies, despite limited treatment access. However, the proliferation of illicit fentanyl use initiated a dramatic and cascading epidemic of lethal overdoses. This rise in fentanyl overdoses regenerated an interest in vaccine immunotherapy, which, despite an optimistic start in animal models over the past 50 years, yielded disappointing results in human clinical trials of vaccines against nicotine, stimulants (cocaine and methamphetamine), and opioids. After a brief review of clinical and selected preclinical vaccine studies, the "lessons learned" from the previous vaccine clinical trials are summarized, and then the newest challenge of a vaccine against fentanyl and its analogs is explored. Animal studies have made significant advances in vaccine technology for SUD treatment over the past 50 years, and the resulting anti-fentanyl vaccines show remarkable promise for ending this epidemic of fentanyl deaths.

Biopharmaceuticals against substance use disorders - Present and future

BACKGROUND AND OBJECTIVES

Pharmacological treatments available for substance use disorder (SUD) focus on pharmacodynamics, agonizing or antagonizing the drug of abuse (DOA) on receptor level. Drawbacks of this approach include the reliance on long-term patient compliance, on-target off-site effects, perpetuation of addiction and unavailability for many DOAs. Newer, pharmacokinetic approaches are needed that restrict DOA's access to the brain or disrupt DOA-instated brain changes maintaining addiction. Biotechnology might be able to provide the right biopharmaceutical tools to deliver a fine-tuned solution with less side effects compared to currently available treatments.

METHODS

This review examines the available literature on biopharmaceuticals developed to treat SUD.

RESULTS

Active and passive immunization, metabolic enhancers that augment DOA metabolism and clearance, as well as genetic/epigenetic modulation are promising next generation SUD treatments. Active immunization relies on production of antidrug antibodies by means of vaccination, while passive immunization constitutes of exogenous administration of such antibodies. Metabolic enhancers include drug-specific metabolizing enzymes that can be administered or secreted by modified skin grafts, as well as catalytic antibodies that hasten DOA metabolism. Nanotechnological advances can also allow for brain delivery of siRNAs, mRNAs or DNA in order to modulate central, common in all addictions, genetic or epigenetic targets attenuating drug seeking behavior and reversing drug-induced brain changes.

CONCLUSIONS

and Scientific Significance: Biopharmaceuticals can in the future complement or even replace traditional pharmacodynamics approaches in SUD treatment. While passive and active immunization biopharmaceuticals have entered human clinical trials, metabolic enhancers and genetic approaches are at the preclinical level.

Exploring the Role of DARPP-32 in Addiction: A Review of the Current Limitations of Addiction Treatment Pathways and the Role of DARPP-32 to Improve Them

We are amidst a global addiction crisis, yet stigmas surrounding addiction counterintuitively prevail. Understanding and appreciating the neurobiology of addiction is essential to dissolve this stigma and for the development of new pharmacological agents to improve upon currently narrow therapeutic options. This review highlights this and evaluates dopamine-and-cAMP-regulated phosphoprotein, Mr 32 kDa (DARPP-32) as a potential target to treat various forms of substance abuse. Despite the proven involvement of DARPP-32 in addiction pathophysiology, no robust investigations into compounds that could pharmacologically modulate it have been carried out. Agents capable of altering DARPP-32 signalling in this way could prevent or reverse drug abuse and improve upon currently substandard treatment options.

A Scoping Review of Drug Epidemic Models

The phenomenon of drug epidemics has been a global issue in the past decades, causing enormous damages to the physical and mental health of drug users and social well-being. Despite great efforts to curb drug epidemics at the governmental or social level, the total number of drug users has still been on the rise in recent years, along with illicit production and trafficking around the world. Inspired by dynamical epidemic models of infectious disease, a flourishment of promising results has been observed in the exploration of drug epidemic models. In this review, we aim to provide a scoping review of all existing drug epidemic modeling studies, and it has been shown that most studies focused on analyses of theoretical behaviors of the model systems, lacking emphasis on practical applications in real settings. We found that the drug epidemic models were characterized by a longer time scale, no incubation period, no significant prevention vaccines interfered, and population specificity. This review could assist policymakers and public health workers in gaining deeper insights into modeling tools, and help modelers improve their works, thus narrowing gaps between mathematical epidemiology and public health studies.

Current status of vaccines for substance use disorders: A brief review of human studies

Substance use is a major public health concern worldwide. In the United States, drug-related deaths have increased many-fold in the past two decades due to the infiltration of more potent and lethal drugs such as fentanyl. Despite significant advancement in medicine, the management of substance use disorders (SUD) continues to be fraught with high attrition, relapse, morbidity, and mortality. The conceptual transition of a SUD from a moral failing to a chronic disease caused by substances facilitated the expansion of biological treatments, including pharmacotherapy, neurostimulation, and immunotherapy. While the quest for vaccines against drugs of abuse had an optimistic start in animal models, clinical trials in humans have yielded disappointing results. This paper provides a brief review on the current progress of vaccines against nicotine, stimulants (cocaine and methamphetamine), opioids including fentanyl, novel psychoactive substances (synthetic cathinones and synthetic cannabis), and discusses prospects for vaccine technology in the treatment of SUD.

Cognitive Training Effectiveness on Memory, Executive Functioning, and Processing Speed in Individuals With Substance Use Disorders: A Systematic Review

Background: Cerebral neuroplasticity is compromised due to substance abuse. There is damage to neuronal areas that are involved in memory and executive functioning. Treatments with worse outcomes are often associated with cognitive deficits that have resulted from substance dependence. However, there is evidence that cognitive training can lead to improvements in cognitive functions and can be useful when treating addictions. This systematic review aims to synthesize evidence on the effectiveness of cognitive training in memory, executive functioning, and processing speed in individuals with substance use disorder (SUD).

Methods: The Joanna Briggs Institute's PICO strategy was used to develop this systematic literature review. Four databases were searched (PubMed, the Cochrane Library, Web of Science, and PsycINFO) to identify controlled randomized clinical studies and quasi-experimental studies, in English, Portuguese, and Spanish, from 1985 to 2019. The literature found was examined by two independent reviewers, who assessed the quality of studies that met the inclusion criteria. The Cochrane risk-of-bias tool for the randomized controlled trials and the ROBINS-I tool for non-randomized studies were used to assess the risk of bias. In data extraction, the Cochrane Handbook for Systematic Reviews was considered.

Results: From a total of 470 studies, 319 were selected for analysis after the elimination of duplicates. According to the inclusion criteria defined, 26 studies were eligible and evaluated. An evaluation was performed considering the participant characteristics, countries, substance type, study and intervention details, and key findings. Of the 26 selected studies, 14 considered only alcoholics, six included participants with various SUD (alcohol and other substances), three exclusively looked into methamphetamine-consuming users and another three into opioid/methadone users. Moreover, 18 studies found some kind of cognitive improvement, with two of these reporting only marginally significant effects. One study found improvements only in measures similar to the training tasks, and two others had ambiguous results.

Conclusions: The included studies revealed the benefits of cognitive training with regard to improving cognitive functions in individuals with SUD. Memory was the most scrutinized cognitive function in this type of intervention, and it is also one of the areas most affected by substance use.

Systematic Review Registration: [PROSPERO], identifier [CRD42020161039].

Solving the Opioid Crisis Isn't Just a Public Health Challenge-It's a Bioethics Challenge

Among those who discuss America's opioid crisis, it is popular to claim that we know what we, as a society, ought to do to solve the problem-we simply don't want it badly enough. We don't lack knowledge; we lack the will to act and to fund the right policies. In fact, I've heard two versions of this. Among those who focus on prescription opioids, it is clear that we ought to stop prescribing so many powerful opioid painkillers. And among my public health colleagues focusing on illicit drug use, it is clear that we ought to expand addiction treatment and harm-reduction services. The problem, however, is that the second claim is not obvious (and, indeed, is denied by many Americans), and the first claim probably isn't even true (at least, not in so crude a form). In short, the opioid crisis presents not only a problem of political will but also one of ethics. It will take work to discover or justify our normative claims in this arena.

Therapeutic and Prophylactic Vaccines to Counteract Fentanyl Use Disorders and Toxicity

The incidence of fatal overdoses has increased worldwide due to the widespread access to illicit fentanyl and its potent analogues. Vaccines offer a promising strategy to reduce the prevalence of opioid use disorders (OUDs) and to prevent toxicity from accidental and deliberate exposure to fentanyl and its derivatives. This study describes the development and characterization of vaccine formulations consisting of novel fentanyl-based haptens conjugated to carrier proteins. Vaccine efficacy was tested against opioid-induced behavior and toxicity in mice and rats challenged with fentanyl and its analogues. Prophylactic vaccination reduced fentanyl- and sufentanil-induced antinociception, respiratory depression, and bradycardia in mice and rats. Therapeutic vaccination also reduced fentanyl intravenous self-administration in rats. Because of their selectivity, vaccines did not interfere with the pharmacological effects of commonly used anesthetics nor with methadone, naloxone, oxycodone, or heroin. These preclinical data support the translation of vaccines as a viable strategy to counteract fentanyl use disorders and toxicity.