Vaccines against drugs of abuse: where are we now?

Chemical tools for the opioids

The opioids are potent and widely used pain management medicines despite also possessing severe liabilities that have fueled the opioid crisis. The pharmacological properties of the opioids primarily derive from agonism or antagonism of the opioid receptors, but additional effects may arise from specific compounds, opioid receptors, or independent targets. The study of the opioids, their receptors, and the development of remediation strategies has benefitted from derivatization of the opioids as chemical tools. While these studies have primarily focused on the opioids in the context of the opioid receptors, these chemical tools may also play a role in delineating mechanisms that are independent of the opioid receptors. In this review, we describe recent advances in the development and applications of opioid derivatives as chemical tools and highlight opportunities for the future.

Development of Methamphetamine Conjugated Vaccine through Hapten Design: In Vitro and In Vivo Characterization

BACKGROUND

Methamphetamine (METH) substance-use disorder is an ever-growing global health issue with no effective treatment. Anti-METH vaccines are under investigation as an alternative to existing psychological interventions. This platform has made significant progress over past decades mainly in preclinical stages, and efforts to develop an anti-METH vaccine with a high antibody response are of utmost importance.

METHODOLOGY

A novel conjugated anti-METH vaccine was developed using METH HCl as the starting material for the design of hapten, a peptide linker consisting of five lysines and five glycines, and finally immunogenic carrier mannan, which is novel to this platform. All the chemical reaction steps were confirmed by several analytical techniques, and the immunogenicity of the developed vaccine was investigated in a mouse model.

RESULTS

Thin-layer chromatography and gas chromatography confirmed the reaction between METH and peptide linker. UV, NMR and color tests were used to confirm the presence of the aldehyde groups in oxidized mannan (OM). The final conjugated vaccine was confirmed by UV and LC-MS. The stability of mannan, the METH hapten, and the final vaccine was evaluated by UV and LC-MS and demonstrated satisfactory stability over 3 months in various storage conditions. Animal studies supported the immunogenicity of the novel vaccine.

CONCLUSIONS

We successfully developed and characterized a novel METH vaccine in vitro and in vivo. The present study findings are encouraging and will form the basis of further exploration to assess its effectiveness to prevent METH addiction in preclinical models.

Development of an Effective Monoclonal Antibody against Heroin and Its Metabolites Reveals Therapies Have Mistargeted 6-Monoacetylmorphine and Morphine over Heroin

The opioid epidemic is a global public health crisis that has failed to abate with current pharmaceutical treatments. Moreover, these FDA-approved drugs possess numerous problems such as adverse side effects, short half-lives, abuse potential, and recidivism after discontinued use. An alternative treatment model for opioid use disorders is immunopharmacotherapy, where antibodies are produced to inhibit illicit substances by sequestering the drug in the periphery. Immunopharmacotherapeutics against heroin have engaged both active and passive vaccines targeting heroin's metabolites, 6-monoacetylmorphine (6-AM) and morphine, since decades of research have stated that heroin's psychoactive and lethal effects are mainly attributed to these compounds. However, concerted efforts to develop effective immunopharmacotherapies against heroin abuse have faced little clinical advancement, suggesting a need for reassessing drug target selection. To address this issue, four unique monoclonal antibodies were procured with distinct affinity to either heroin, 6-AM, or morphine. Examination of these antibodies through in vitro and in vivo tests revealed monoclonal antibody 11D12 as the optimal therapeutic and provided crucial insights into the key chemical species to target for blunting heroin's psychoactive and lethal effects. These findings offer clarification into the problematic attempts of therapeutics targeting heroin's metabolites and provide a path forward for future heroin immunopharmacotherapy development.

Immunotherapies for the Treatment of Drug Addiction

Substance use disorders (SUD) are a serious public health concern globally. Existing treatment platforms suffer from a lack of effectiveness. The development of immunotherapies against these substances of abuse for both prophylactic and therapeutic use has gained tremendous importance as an alternative and/or supplementary to existing therapies. Significant development has been made in this area over the last few decades. Herein, we highlight the vaccine and other biologics development strategies, preclinical, clinical updates along with challenges and future directions. Articles were searched in PubMed, ClinicalTrial.gov, and google electronic databases relevant to development, preclinical, clinical trials of nicotine, cocaine, methamphetamine, and opioid vaccines. Various new emerging vaccine development strategies for SUD were also identified through this search and discussed. A good number of vaccine candidates demonstrated promising results in preclinical and clinical phases and support the concept of developing a vaccine for SUD. However, there have been no ultimate success as yet, and there remain some challenges with a massive push to take more candidates to clinical trials for further evaluation to break the bottleneck.

Development and characterization of a novel conjugated methamphetamine vaccine

BACKGROUND

Methamphetamine (METH) addiction is a major public health concern globally with limited management options. The development of a METH vaccine through hapten design has received significant attention as a promising platform for the potential treatment of METH addiction and overdose, however there is yet to be a successful candidate in human trials.

RESEARCH DESIGN AND METHODS

In this study, we developed a novel conjugated METH vaccine using oxidized mannan (a polymannose) as an immunogenic carrier. A METH hapten was synthesized by using amphetamine and conjugated to mannan with a (Lysine-Glycine-Lysine-Glycine-lysine-Glycine-Lysine-Glycine-Lysine-Glycine) (KG)₅ peptide linker.

RESULTS

The reaction between amphetamine and (KG)₅, oxidation of mannan, and conjugation of amphetamine-(KG)₅ with oxidized mannan were confirmed by color tests, Fourier-transform infrared spectroscopy, gas and liquid chromatography mass spectrometry, thin-layer chromatography, and ultraviolet spectrophotometer. Additionally, the ability of the vaccine to generate antibodies was confirmed in C57BL/6 mice.

CONCLUSIONS

The successful development and characterization of the METH-mannan conjugate vaccine, provides a potential therapeutic intervention to curb METH substance use disorders. Each step of vaccine development was characterized to aid in future research on these vaccines, and the immunogenicity shown in the animal models supports future evaluation of the approach. Future studies of the conjugated METH vaccine should evaluate the efficacy in animal models of acute and chronic METH to pave the way for human studies.

Immune to addiction: how immunotherapies can be used to combat methamphetamine addiction

Introduction: The concept of anti-methamphetamine (METH) immunotherapies is a few decades old. A substantial amount of information has been generated on the development of anti-METH immunotherapies, particularly in the preclinical stages of development of vaccines and monoclonal antibody (mAb) treatments. However, the concept of treating METH use addiction with anti-METH immunotherapies is not well understood by many researchers or general readers. A series of questions commonly arise regarding the concept: how does it work? What is the antigen used? How exactly does the vaccine prevent METH addiction?Areas covered: This paper reviews the published articles relating to the mechanisms of METH use disorders, strategies used in the development of anti-METH immunotherapies, and the mechanism of action of these treatments. It provides clear explanations to questions surrounding the basis of anti-METH immunotherapies and contextualizes their development. It also identifies areas for future investigation to speed their translation into clinical use.Expert opinion: While METH immunotherapies, including vaccines and mAbs, have progressed significantly in the last 30 years, there are newer approaches that should be evaluated to improve their translatability. Approaches including nanoparticle vaccines, virus-like particles, and other novel methods should be fully evaluated as means of generating anti-METH immunity.

Synthesis of 3-O-Carboxyalkyl Morphine Derivatives and Characterization of Their Acid-Base Properties

The C-3 phenolic hydroxy group containing morphine derivatives (morphine, oxymorphone, naloxone, naltrexone) are excellent candidates for the synthesis of 3-O-functionalized molecules. Achieving free carboxylic group containing derivatives gives the opportunity for further modification and conjugation that could be used for immunization and immunoassays. For this purpose ethyl bromo- and chloroacetate can be used as O-alkylating agents. Hydrolyzing the products affords the appropriate free carboxylic group containing 3-O-carboxyalkyl derivatives. As these molecules contain an acidic and a basic functional group the protonation macro- and microconstants were determined too, using pH-potentiometry and NMR-pH titration, beside fully characterizing their structure using IR, CD, NMR and HR-MS measurements.

Pharmacotherapy of Patients Taking New Psychoactive Substances: A Systematic Review and Analysis of Case Reports

Background: In recent years, an increase in the frequency of hospitalizations of patients taking newer and newer psychoactive substances has been observed around the world. Each year, authors publish case reports of patients who consumed previously unknown NPS. Most publications of this type concern the period between 2014 and 2016. However, no publication systematically reviews the pharmacotherapy used in these cases. This study aims to review the case reports of patients taking NPS published between 2010 and 2019, as well as analyzing the pharmacotherapy used. Methods: We searched the Thomson (Web of Knowledge), PubMed/Medline, Science Direct, Scopus and Google Scholar databases. The search was performed using all possible combinations of the term "case report" describing the use of NPS, also referred to as designer medications, internet medications, research chemicals and herbal highs. Results: We analyzed 51 case reports on the intake of various types of NPS. Most of them (p < 0.001) concerned the use of synthetic cannabinoids (41.2%) and cathinones (31.4%). The pharmacotherapy applied primarily (p < 0.001) consisted of administering benzodiazepines to patients (62.7%), most of whom took only this group of medications (25.5%), followed by groups receiving benzodiazepines combined with neuroleptics (15.7%) and muscle relaxants (11.8%). Opioids were administered primarily to patients taking synthetic opioids (p < 0.001). Of the 5 cases of deaths from NPS reported in the literature, three relate specifically to the synthetic opioid MT-45. The later the time period, the more medications patients were administered (p = 0.02). Conclusion: In the pharmacotherapy for NPS poisoning, one should focus primarily on combating psychomotor agitation.

Vaccine development against methamphetamine drug addiction

INTRODUCTION

There are currently no effective treatments for Methamphetamine (METH) addiction and psychotherapy remains the sole treatment option. The development of immunopharmacotherapies for the treatment of drug addiction, overdose, and relapse management appears to be promising alternative and a significant body of information has been generated using various vaccine development strategies. Herein, we present an update on the developments toward anti-METH vaccines and their study outcomes in preclinical and clinical studies.

AREAS COVERED

The scope of this article is to present an update on METH vaccine development strategies such as active vaccination through hapten design and the passive immunization through monoclonal antibodies along with preclinical and clinical studies. The relevant literatures and clinical trial outcomes were searched in databases including Google, Google Scholar, PubMed, Science Direct, ClinicalTrials.gov, and www.anzctr.org.au using specific keywords.

EXPERT OPINION

Significant improvements have been developed for immunopharmacotherapies for METH addiction over the last two decades. However, only one monoclonal antibody candidate has been evaluated in a phase I clinical trial. At this moment, it is essential to evaluate the safety and efficacy of potential candidates in clinical trials to validate the importance of this platform drug-vaccine conjugation in order to manage or overcome METH addiction.

Synthesis of Potential Haptens with Morphine Skeleton and Determination of Protonation Constants

Vaccination could be a promising alternative warfare against drug addiction and abuse. For this purpose, so-called haptens can be used. These molecules alone do not induce the activation of the immune system, this occurs only when they are attached to an immunogenic carrier protein. Hence obtaining a free amino or carboxylic group during the structural transformation is an important part of the synthesis. Namely, these groups can be used to form the requisite peptide bond between the hapten and the carrier protein. Focusing on this basic principle, six nor-morphine compounds were treated with ethyl acrylate and ethyl bromoacetate, while the prepared esters were hydrolyzed to obtain the N-carboxymethyl- and N-carboxyethyl-normorphine derivatives which are considered as potential haptens. The next step was the coupling phase with glycine ethyl ester, but the reactions did not work or the work-up process was not accomplishable. As an alternative route, the normorphine-compounds were N-alkylated with N-(chloroacetyl)glycine ethyl ester. These products were hydrolyzed in alkaline media and after the work-up process all of the derivatives contained the free carboxylic group of the glycine side chain. The acid-base properties of these molecules are characterized in detail. In the N-carboxyalkyl derivatives, the basicity of the amino and phenolate site is within an order of magnitude. In the glycine derivatives the basicity of the amino group is significantly decreased compared to the parent compounds (i.e., morphine, oxymorphone) because of the electron withdrawing amide group. The protonation state of the carboxylate group significantly influences the basicity of the amino group. All of the glycine ester and the glycine carboxylic acid derivatives are currently under biological tests.

Optimization of a multivalent peptide vaccine for nicotine addiction

We have been optimizing the design of a conjugate vaccine for nicotine addiction that employs a peptide-based hapten carrier. This peptide, which is produced by solid-phase protein synthesis, contains B cell and T cell epitope domains and eliminates the non-relevant, but highly immunogenic sequences in microbial carriers. In this report, the amino acid sequences in the T cell domain were optimized for improved vaccine activity and multivalent formulations containing structurally distinct haptens were tested for the induction of additive antibody responses. Trivalent vaccines produced antibody concentrations in mice that were 100 times greater than the amount of nicotine measured in smokers, and significantly reduced acute nicotine toxicity in rats. Two additional features were explored that distinguish the peptide from traditional recombinant carriers. The first is the minimal induction of an anti-carrier response, which can suppress nicotine vaccine activity. The second employs solid-phase synthesis to manufacture haptenated peptide. This approach obviates conventional conjugation chemistries and streamlines production of a more potent vaccine antigen.

Paradox of PEGylation in fabricating hybrid nanoparticle-based nicotine vaccines

Polyethylene glycol (PEG) has long been used in nanoparticle-based drug or vaccine delivery platforms. In this study, nano-nicotine vaccines (NanoNicVac) were PEGylated to different degrees to investigate the impact of PEG on the immunological efficacy of the vaccine. Hybrid nanoparticles with various degrees of PEGylation (2.5%-30%) were assembled. It was found that 30% PEGylation resulted in a hybrid nanoparticle of a compromised core-shell structure. A higher concentration of PEG also led to a slower cellular uptake of hybrid nanoparticles by dendritic cells. However, increasing the quantity of the PEG could effectively reduce nanoparticle aggregation during storage and improve the stability of the hybrid nanoparticles. Subsequently, nicotine vaccines were synthesized by conjugating nicotine haptens to the differently PEGylated hybrid nanoparticles. In both in vitro and in vivo studies, it was found that a nicotine vaccine with 20% PEGylation (NanoNicVac 20.0) was significantly more stable than the vaccines with lower PEGylation. In addition, NanoNicVac 20.0 induced a significantly higher anti-nicotine antibody titer of 3.7 ± 0.6 × 104 in mice than the other NanoNicVacs with lower concentrations of PEG. In a subsequent pharmacokinetic study, the lowest brain nicotine concentration of 34 ± 11 ng/g was detected in mice that were immunized with NanoNicVac 20.0. In addition, no apparent adverse events were observed in mice immunized with NanoNicVac. In summary, 20% PEGylation confers NanoNicVac with desirable safety, the highest stability, and the best immunological efficacy in mice.

Novel technologies in detection, treatment and prevention of substance use disorders

Substance use disorders are a widely recognized problem, which affects various levels of communities and influenced the world socioeconomically. Its source is deeply embedded in the global population. In order to fight against such an adversary, governments have spared no efforts in implementing substance abuse treatment centers and funding research to develop treatments and prevention procedures. In this review, we will discuss the use of immunological-based treatments and detection kit technologies. We will be detailing the steps followed to produce performant antibodies (antigens, carriers, and adjuvants) focusing on cocaine and methamphetamine as examples. Furthermore, part of this review is dedicated to substance use detection. Owing to novel technologies such as bio-functional polymeric surfaces and biosensors manufacturing, detection has become a more convenient method with the fast and on-site developed devices. Commercially available devices are able to test substance use disorders in urine, saliva, hair, and sweat. This improvement has had a tremendous impact on the prevention of driving under influence and other illicit behaviors. Lastly, substance abuse became a major issue involving the cooperation of experts on all levels to devise better treatment programs and prevent abuse-based accidents, injury and death.

Investigations into the efficacy of multi-component cocaine vaccines

Although cocaine addiction remains a serious health and societal problem in the United States, no FDA-approved treatment has been developed. Vaccines offer an exciting strategy for the treatment of cocaine addiction; however, vaccine formulations need to be optimized to improve efficacy. Herein, we examine the effectiveness of a tricomponent cocaine vaccine, defined as having its hapten (GNE) and adjuvant (cytosine-guanine oligodeoxynucleotide 1826, CpG ODN 1826) covalently linked via the immunogenic protein ovalbumin (OVA). The tricomponent vaccine (GNE-OVA-CpG 1826) and a vaccine of analogous, individual components (GNE-OVA+CpG ODN 1826) were found to similarly induce highly specific anticocaine antibody production in mice and block cocaine's stimulant effects in hyperlocomotor testing.

Ethical Implications in Vaccine Pharmacotherapy for Treatment and Prevention of Drug of Abuse Dependence

Different immunotherapeutic approaches are in the pipeline for the treatment of drug dependence. "Drug vaccines" aim to induce the immune system to produce antibodies that bind to drugs and prevent them from inducing rewarding effects in the brain. Drugs of abuse currently being tested using these new approaches are opioids, nicotine, cocaine, and methamphetamine. In human clinical trials, "cocaine and nicotine vaccines" have been shown to induce sufficient antibody levels while producing few side effects. Studies in humans, determining how these vaccines interact in combination with their target drug, are underway. However, although vaccines can become a reasonable treatment option for drugs of abuse, there are several disadvantages that must be considered. These include i) great individual variability in the formation of antibodies, ii) the lack of protection against a structurally dissimilar drug that produces the same effects as the drug of choice, and iii) the lack of an effect on the drug desire that may predispose an addict to relapse. In addition, a comprehensive overview of several crucial ethical issues has not yet been widely discussed in order to have not only a biological approach to immunotherapy of addiction. Overall, immunotherapy offers a range of possible treatment options: the pharmacological treatment of addiction, the treatment of overdoses, the prevention of toxicity to the brain or the heart, and the protection of the fetus during pregnancy. So far, the results obtained from a small-scale experiment using vaccines against cocaine and nicotine suggest that a number of important technical challenges still need to be overcome before such vaccines can be approved for clinical use.

Current status of vaccines in psychiatry-A narrative review

INTRODUCTION

Vaccines are one of the newer therapeutic modalities being researched in psychiatric illnesses with limited role of pharmacological interventions. Preclinical studies on vaccines have shown favorable results in conditions like Substance use Disorders and Alzheimer's Dementia. However, the utility of Mumps Measles Rubella vaccine has been overshadowed by controversy linked to causation of Autism. With this background, the current narrative review aimed to comprehensively and critically evaluate the current status of vaccines in Psychiatric illnesses.

METHODS

Preliminary literature search using the electronic databases of MEDLINE and Google Scholar between May 1967 and May 2017 using the search terms "Vaccines" and "Psychiatry" was carried out and articles were found in the following areas of research: Substance use, Alzheimer Dementia, Autism, Human Immunodeficiency Virus and Human Papilloma Virus Further, the refined search was done using combinations of search terms "Vaccine", "Nicotine", "Cocaine", "Opioid", "Alzheimer Dementia", "Autism", and "Pervasive Developmental Disorders" and peer - reviewed original articles published in English conducted among human subjects and published in English language were included for review.

RESULTS

A total of 31 articles found eligible were organized into appropriate sections synthesizing the literature on role of vaccines in specific disorders such as Substance Use Disorders, Alzheimer Dementia and Pervasive Developmental Disorders.

DISCUSSION

The therapeutic potential of vaccines in Substance Use Disorders and Alzheimer Dementia was found to be limited in comparison to the results from animal studies. Safety profile of the immunogens and the adjuvants in humans is possibly the most important limitation. No causal association between Measles Mumps Rubella vaccine and Autism was found.

Promising roles for pharmacists in addressing the U.S. opioid crisis

Overdoses of prescription or illicit opioids claimed the lives of 116 Americans each day in 2016, and the crisis continues to escalate. As healthcare systems evolve to address the crisis, the potential of pharmacists to make a positive difference is significant. In addition to utilizing available prescription drug monitoring programs to help prevent diversion of opioids, practicing pharmacists can be alert for signs of opioid misuse by patients (e.g., multiple prescriptions from different physicians) as well as inappropriate prescribing or hazardous drug combinations that physicians may not be aware of (e.g., opioid analgesics combined with benzodiazepines). They can also supply patients with information on risks of opioids, proper storage and disposal of medications, and the harms (and illegality) of sharing medications with other people. Increasingly, pharmacies are sites of distribution of the opioid antagonist naloxone, which has been shown to save lives when made available to opioid users and their families or other potential bystanders to an overdose; and pharmacists can provide guidance about its use and even legal protections for bystanders to an overdose that customers may not be aware of. Pharmacists can also recommend addiction treatment to patients and be a resource for information on addiction treatment options in the community. As addiction treatment becomes more integrated with general healthcare, pharmacies are also increasingly dispensing medications like buprenorphine and, in the future, possibly methadone. Pharmacists in private research labs and at universities are helping to develop the next generation of addiction treatments and safer, non-addictive pain medications; they can also play a role in implementation research to enhance the delivery of addiction interventions and medications in pharmacy settings. Meanwhile, pharmacists in educational settings can promote improved education about the neurobiology and management of pain and its links to opioid misuse and addiction.

Vaccine-driven pharmacodynamic dissection and mitigation of fenethylline psychoactivity

Fenethylline, also known as Captagon, is a synthetic psychoactive stimulant that has recently been linked to substance use disorder and ‘pharmacoterrorism’ in the Middle East.^1–4 Although fenethylline shares a common phenethylamine core with other amphetamine-type stimulants, it additionally incorporates a covalently-linked xanthine moiety into its parent structure.^5,6 These independently-active pharmacophores are liberated during metabolism, resulting in a structurally-diverse chemical mixture being deployed to the central nervous system.^7–9 Although fenethylline’s psychoactive properties have been reported to differ from other synthetic stimulants, the in vivo chemical complexity it manifests upon ingestion has impeded efforts to unambiguously identify the specific species responsible for these effects.^10,11 Here we develop a ‘dissection through vaccination’ approach, called DISSECTIV, to mitigate fenethylline’s psychoactivity and show that its rapid-onset and distinct psychoactive properties are facilitated by functional synergy between theophylline and amphetamine. Our results demonstrate that incremental vaccination against single chemical species within a multi-component mixture can be used to uncover emergent properties arising from polypharmacologic activity. We anticipate that DISSECTIV will be employed to expose unidentified active chemical species and illuminate pharmacodynamic interactions within other chemically complex systems, such as those found in counterfeit or illegal drug preparations, post-metabolic tissue samples, and natural product extracts.

Augmenting the efficacy of anti-cocaine catalytic antibodies through chimeric hapten design and combinatorial vaccination

Given the need for further improvements in anti-cocaine vaccination strategies, a chimeric hapten (GNET) was developed that combines chemically-stable structural features from steady-state haptens with the hydrolytic functionality present in transition-state mimetic haptens. Additionally, as a further investigation into the generation of an improved bifunctional antibody pool, sequential vaccination with steady-state and transition-state mimetic haptens was undertaken. While GNET induced the formation of catalytically-active antibodies, it did not improve overall behavioral efficacy. In contrast, the resulting pool of antibodies from GNE/GNT co-administration demonstrated intermediate efficacy as compared to antibodies developed from either hapten alone. Overall, improved antibody catalytic efficiency appears necessary to achieve the synergistic benefits of combining cocaine hydrolysis with peripheral sequestration.

Efficacy of an adenovirus-based anti-cocaine vaccine to reduce cocaine self-administration and reacqusition using a choice procedure in rhesus macaques

Immunopharmacotherapy offers an approach for treating cocaine abuse by specifically targeting the cocaine molecule and preventing its access to the CNS. dAd5GNE is a novel cocaine vaccine that attenuates the stimulant and the reinforcing effects of cocaine in rats. The goal of this study was to extend and validate dAd5GNE vaccine efficacy in non-human primates. Six experimentally naïve adult female rhesus monkeys (Macaca mulatta) were trained to self-administer 0.1mg/kg/injection intravenous (i.v.) cocaine or receive candy; then 4 monkeys were administered the vaccine and 2 monkeys were administered vehicle intramuscularly, with additional vaccine boosts throughout the study. The reinforcing effects of cocaine were measured during self-administration, extinction, and reacquisition (relapse) phases. Serum antibody titers in the vaccinated monkeys remained high throughout the study. There was no change in the preference for cocaine over candy over a 20-week period in 5 of the 6 monkeys; only one of the 4 (25%) vaccinated monkeys showed a decrease in cocaine choice. All 6 monkeys extinguished responding for cocaine during saline extinction testing; vaccinated monkeys tended to take longer to extinguish responding than control monkeys (17.5 vs. 7.0 sessions). Vaccination substantially retarded reacquisition of cocaine self-administration; control monkeys resumed cocaine self-administration within 6-41 sessions and 1 vaccinated monkey resumed cocaine self-administration in 19 sessions. The other 3 vaccinated monkeys required between 57 and 94 sessions to resume cocaine self-administration even in the context of employing several manipulations to encourage cocaine reacquisition. These data suggest that the dAdGNE vaccine may have therapeutic potential for humans who achieve cocaine abstinence as part of a relapse prevention strategy.

Biologics to treat substance use disorders: Current status and new directions

Biologics (vaccines, monoclonal antibodies (mAb), and genetically modified enzymes) offer a promising class of therapeutics to treat substance use disorders (SUD) involving abuse of opioids and stimulants such as nicotine, cocaine, and methamphetamine. In contrast to small molecule medications targeting brain receptors, biologics for SUD are larger molecules that do not cross the blood-brain barrier (BBB), but target the drug itself, preventing its distribution to the brain and blunting its effects on the central nervous system (CNS). Active and passive immunization approaches rely on antibodies (Ab) that bind drugs of abuse in serum and block their distribution to the brain, preventing the rewarding effects of drugs and addiction-related behaviors. Alternatives to vaccines and anti-drug mAb are genetically engineered human or bacterial enzymes that metabolize drugs of abuse, lowering the concentration of free active drug. Pre-clinical and clinical data support development of effective biologics for SUD.

Efficacy, but not antibody titer or affinity, of a heroin hapten conjugate vaccine correlates with increasing hapten densities on tetanus toxoid, but not on CRM197 carriers

Vaccines against drugs of abuse have induced antibodies in animals that blocked the biological effects of the drug by sequestering the drug in the blood and preventing it from crossing the blood-brain barrier. Drugs of abuse are too small to induce antibodies and, therefore, require conjugation of drug hapten analogs to a carrier protein. The efficacy of these conjugate vaccines depends on several factors including hapten design, coupling strategy, hapten density, carrier protein selection, and vaccine adjuvant. Previously, we have shown that 1 (MorHap), a heroin/morphine hapten, conjugated to tetanus toxoid (TT) and mixed with liposomes containing monophosphoryl lipid A [L(MPLA)] as adjuvant, partially blocked the antinociceptive effects of heroin in mice. Herein, we extended those findings, demonstrating greatly improved vaccine induced antinociceptive effects up to 3% mean maximal potential effect (%MPE). This was obtained by evaluating the effects of vaccine efficacy of hapten 1 vaccine conjugates with varying hapten densities using two different commonly used carrier proteins, TT and cross-reactive material 197 (CRM197). Immunization of mice with these conjugates mixed with L(MPLA) induced very high anti-1 IgG peak levels of 400-1500 μg/mL that bound to both heroin and its metabolites, 6-acetylmorphine and morphine. Except for the lowest hapten density for each carrier, the antibody titers and affinity were independent of hapten density. The TT carrier based vaccines induced long-lived inhibition of heroin-induced antinociception that correlated with increasing hapten density. The best formulation contained TT with the highest hapten density of ≥30 haptens/TT molecule and induced %MPE of approximately 3% after heroin challenge. In contrast, the best formulation using CRM197 was with intermediate 1 densities (10-15 haptens/CRM197 molecule), but the %MPE was approximately 13%. In addition, the chemical synthesis of 1, the optimization of the conjugation method, and the methods for the accurate quantification of hapten density are described.

60 years of advances in neuropsychopharmacology for improving brain health, renewed hope for progress

Pharmacotherapy is effective in helping many patients suffering from psychiatric and neurological disorders, and both psychotherapeutic and stimulation-based techniques likewise have important roles to play in their treatment. However, therapeutic progress has recently been slow. Future success for improving the control and prevention of brain disorders will depend upon deeper insights into their causes and pathophysiological substrates. It will also necessitate new and more rigorous methods for identifying, validating, developing and clinically deploying new treatments. A field of Research and Development (R and D) that remains critical to this endeavour is Neuropsychopharmacology which transformed the lives of patients by introducing pharmacological treatments for psychiatric disorder some 60 years ago. For about half of this time, the European College of Neuropsychopharmacology (ECNP) has fostered efforts to enhance our understanding of the brain, and to improve the management of psychiatric disorders. Further, together with partners in academia and industry, and in discussions with regulators and patients, the ECNP is implicated in new initiatives to achieve this goal. This is then an opportune moment to survey the field, to analyse what we have learned from the achievements and failures of the past, and to identify major challenges for the future. It is also important to highlight strategies that are being put in place in the quest for more effective treatment of brain disorders: from experimental research and drug discovery to clinical development and collaborative ventures for reinforcing "R and D". The present article sets the scene, then introduces and interlinks the eight articles that comprise this Special Volume of European Neuropsychopharmacology. A broad-based suite of themes is covered embracing: the past, present and future of "R and D" for psychiatric disorders; complementary contributions of genetics and epigenetics; efforts to improve the treatment of depression, neurodevelopmental and neurodegenerative disorders; and advances in the analysis and neuroimaging of cellular and cerebral circuits.

Learning from the past and looking to the future: Emerging perspectives for improving the treatment of psychiatric disorders

Modern neuropsychopharmacology commenced in the 1950s with the serendipitous discovery of first-generation antipsychotics and antidepressants which were therapeutically effective yet had marked adverse effects. Today, a broader palette of safer and better-tolerated agents is available for helping people that suffer from schizophrenia, depression and other psychiatric disorders, while complementary approaches like psychotherapy also have important roles to play in their treatment, both alone and in association with medication. Nonetheless, despite considerable efforts, current management is still only partially effective, and highly-prevalent psychiatric disorders of the brain continue to represent a huge personal and socio-economic burden. The lack of success in discovering more effective pharmacotherapy has contributed, together with many other factors, to a relative disengagement by pharmaceutical firms from neuropsychiatry. Nonetheless, interest remains high, and partnerships are proliferating with academic centres which are increasingly integrating drug discovery and translational research into their traditional activities. This is, then, a time of transition and an opportune moment to thoroughly survey the field. Accordingly, the present paper, first, chronicles the discovery and development of psychotropic agents, focusing in particular on their mechanisms of action and therapeutic utility, and how problems faced were eventually overcome. Second, it discusses the lessons learned from past successes and failures, and how they are being applied to promote future progress. Third, it comprehensively surveys emerging strategies that are (1), improving our understanding of the diagnosis and classification of psychiatric disorders; (2), deepening knowledge of their underlying risk factors and pathophysiological substrates; (3), refining cellular and animal models for discovery and validation of novel therapeutic agents; (4), improving the design and outcome of clinical trials; (5), moving towards reliable biomarkers of patient subpopulations and medication efficacy and (6), promoting collaborative approaches to innovation by uniting key partners from the regulators, industry and academia to patients. Notwithstanding the challenges ahead, the many changes and ideas articulated herein provide new hope and something of a framework for progress towards the improved prevention and relief of psychiatric and other CNS disorders, an urgent mission for our Century.

Current approaches for the discovery of drugs that deter substance and drug abuse

INTRODUCTION

Much has been presented and debated on the topic of drug abuse and its multidimensional nature, including the role of society and its customs and laws, economical factors, and the magnitude and nature of the burden. Given the complex nature of the receptors and pathways implicated in regulation of the cognitive and behavioral processes associated with addiction, a large number of molecular targets have been interrogated during recent years to discover starting points for development of small-molecule interventions.

AREAS COVERED

This review describes recent developments in the field of early drug discovery for drug abuse interventions with an emphasis on the advances published during the 2012 - 2014 period.

EXPERT OPINION

Technologically, the processes/platforms utilized in drug abuse drug discovery are nearly identical to those used in the other disease areas. A key complicating factor in drug abuse research is the enormous biological complexity surrounding the brain processes involved and the associated difficulty in finding 'good' targets and achieving exquisite selectivity of treatment agents. While tremendous progress has been made during recent years to use the power of high-throughput technologies to discover proof-of-principle molecules for many new targets, next-generation models will be especially important in this field. Examples include: seeking advantageous drug-drug combinations, the use of automated whole-animal behavioral screening systems, advancing our understanding of the role of epigenetics in drug addiction and the employment of organoid-level 3D test platforms (also referred to as tissue-chip or organs-on-chip).