Immunotherapy for the treatment of drug abuse

Development of fentanyl-specific monoclonal antibody (mAb) to antagonize the pharmacological effects of fentanyl

Fentanyl, a critical component of opioid analgesics, poses a severe threat to public health, exacerbating the drug problem due to its potential fatality. Herein, we present two novel haptens designed with different attachment sites conjugated to keyhole limpet hemocyanin (KLH), aiming to develop an efficacious vaccine against fentanyl. KLH-Fent-1 demonstrated superior performance over KLH-Fent-2 in antibody titer, blood-brain distribution, and antinociceptive tests. Consequently, we immunized mice with KLH-Fent-1 to generate fentanyl-specific monoclonal antibodies (mAbs) using the hybridoma technique to compensate for the defects of active immunization in the treatment of opioid overdose and addiction. The mAb produced by hybridoma 9D5 exhibited the ability to recognize fentanyl and its analogs with a binding affinity of 10-10 M. Subsequently, we developed a human IgG1 chimeric mAb to improve the degree of humanization. Pre-treatment with murine and chimeric mAb significantly reduced the analgesic effect of fentanyl and altered its blood-brain biodistribution in vivo. Furthermore, in a mouse model of fentanyl-induced respiratory depression, the chimeric mAb effectively reversed respiratory depression promptly and maintained a certain level during the week. The development of high-affinity chimeric mAb gives support to combat the challenges of fentanyl misuse and its detrimental consequences. In conclusion, mAb passive immunization represents a viable strategy for addressing fentanyl addiction and overdose.

Enhancing Protective Antibodies against Opioids through Antigen Display on Virus-like Particles

Opioid use disorder (OUD) has become a public health crisis, with recent significant increases in the number of deaths due to overdose. Vaccination can provide an attractive complementary strategy to combat OUD. A key for high vaccine efficacy is the induction of high levels of antibodies specific to the drug of abuse. Herein, a powerful immunogenic carrier, virus-like particle mutant bacteriophage Qβ (mQβ), has been investigated as a carrier of a small molecule hapten 6-AmHap mimicking heroin. The mQβ-6-AmHap conjugate was able to induce significantly higher levels of IgG antibodies against 6-AmHap than mice immunized with the corresponding tetanus toxoid-6-AmHap conjugate in head-to-head comparison studies in multiple strains of mice. The IgG antibody responses were persistent with high anti-6-AmHap titers 600 days after being immunized with mQβ-6-AmHap. The antibodies induced exhibited strong binding toward multiple heroin/morphine derivatives that have the potential to be abused, while binding weakly to medications used for OUD treatment and pain relief. Furthermore, vaccination effectively reduced the impacts of morphine on mice in both ambulation and antinociception assays, highlighting the translational potential of the mQβ-6-AmHap conjugate to mitigate the harmful effects of drugs of abuse.

Sensitizing the Efficiency of ICIs by Neoantigen mRNA Vaccines for HCC Treatment

This study builds upon the groundbreaking mRNA vaccine Nobel Prize win in 2023 for COVID-19 prevention, paving the way for next-generation mRNA cancer vaccines to revolutionize immunotherapy. Despite the existing challenges, such as the presence of a suppressive tumor microenvironment and the identification of cancer-associated antigens, recent results from the KEYNOTE-942 trial have successfully demonstrated the effectiveness of mRNA-based cancer treatments, providing clinical evidence for the first time. This trial aimed to evaluate the efficacy and safety of combining immune checkpoint inhibitors with mRNA-based therapies in treating cancer. This advancement undeniably represents new hope for hepatocellular carcinoma (HCC) patients. However, progress in this field remains limited. In this article, we summarized the current state of applying immune checkpoint inhibitors (ICIs) combined with neoantigen mRNA vaccines. Additionally, we discussed potential targets for designing novel mRNA vaccines and potential mRNA vaccine delivery vehicles. The objective of this article is to inspire enthusiasm for the exploration of innovative therapeutic strategies that combine ICIs with neoantigen mRNA vaccines for HCC treatment and HCC prevention.

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.

A humanized anti-cocaine mAb antagonizes the cardiovascular effects of cocaine in rats

The recombinant monoclonal anti-cocaine antibody, h2E2, sequesters cocaine in plasma increasing concentrations more than 10-fold. The increased levels of cocaine in the plasma could have detrimental peripheral effects, particularly on the cardiovascular system. We investigated the duration and magnitude of the effect of cocaine on the rat heart, and if h2E2 could antagonize that effect. Echocardiography was used to evaluate cardiac function under isoflurane anesthesia, while a tail-cuff was used to measure blood pressure. Cocaine was delivered intravenously and the rats were continuously monitored for a total of 45 min. Echocardiography measurements were recorded every 5 min and blood pressure measurements were recorded throughout the duration of the experiment using 30-s cycles. ECG recordings were taken simultaneously with the echocardiography measurements. An increase in ejection fraction was seen after the cocaine push with the maximum change occurring at 25 min. Treatment with h2E2 1 h before the cocaine push did not have any effect on cardiac parameters. Subsequent cocaine treatment had no effect on the ejection fraction, indicating that the antibody-bound cocaine does not affect the heart. This antagonism of cocaine's effects was greatly decreased after 1 week and entirely absent after 1 month. Cocaine in the presence of h2E2 is pharmacologically inert and h2E2 may have additional clinical utility for reversing cocaine effects on the cardiovascular system.

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.

A Vaccine against Benzimidazole-Derived New Psychoactive Substances That Are More Potent Than Fentanyl

New psychoactive substance (NPS) opioids have proliferated within the international drug market. While synthetic opioids are traditionally composed of fentanyl analogues, benzimidazole-derived isotonitazene and its derivatives are the current NPS opioids of concern. Hence, in this study, we implement immunopharmacotherapy wherein antibodies are produced with high titers and nanomolar affinity to multiple benzimidazole-derived NPS opioids (BNO). Notably, these antibodies blunt psychoactive and physiological repercussions from BNO exposure, which was observed through antinociception, whole-body plethysmography, and blood-brain biodistribution studies. Moreover, we detail previously unreported pharmacokinetics of these drugs, which explains the struggle of traditional pharmaceutical opioid antagonists against BNO substances. These findings provide further insight into the in vivo effects of BNO drugs and the development of effective broad-spectrum therapeutics against NPS opioids.

Development of effective therapeutics for polysubstance use disorders

Traditional pharmacotherapies for substance use disorders have focused on mono-substance abuse. However, recent epidemiological studies have found polysubstance use disorders (PUD) are becoming more prevalent and the abuse of adulterated drugs has led to increasing unintentional overdose deaths. Unfortunately, there are no approved pharmacological agents for PUD. Hence, a therapeutic model of interest to address this growing epidemic is immunopharmacotherapy, where individuals are inoculated with conjugate vaccines formulated with haptens that mimic the drug of abuse. These conjugate vaccines have demonstrated significant therapeutic potential against mono-substance abuse, thus recent studies have applied this model to address PUD. This review presents immunopharmacotherapeutic advancements against polysubstance abuse and discusses necessary developments for conjugate vaccines in order to effectively treat this unaddressed epidemic.

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.

Immunopharmacotherapeutic advancements in addressing methamphetamine abuse

Methamphetamine (METH) is an illicit psychostimulant that is known to account for substance abuse disorders globally, second only to opioids, yet has no approved pharmacotherapies. Traditional therapies employ small molecule agonists or antagonists for substance use disorders or overdose reversal by targeting drug-specific receptors in the brain. However, the comprehensive mechanism of METH on multiple sites within the central nervous system (CNS) implies its receptors lack the high affinity and specificity required for an "ideal" drug target. The alternative to pharmacotherapies is to sequester abused drugs in the periphery, effectively eliminating the effects from CNS receptor occupation through pharmacokinetic antagonism. This review presents updates on immunopharmacotherapeutic advancements in addressing methamphetamine abuse by focusing on the cultivation of research optimization strategies regarding hapten chemistry, carrier proteins, and adjuvants implemented in active immunization. Furthermore, we discuss necessary developments for each component of active immunopharmacotherapies and the future of active vaccines in treating METH use disorder.

Modulation of Attentional Bias to Drug and Affective Cues by Therapeutic and Neuropsychological Factors in Patients With Opioid Use Disorder on Methadone Maintenance Therapy

Objective: Abnormal selective attention to drug cues and negative affect is observed in patients with substance dependence, and it is closely associated with drug addiction and relapse. Methadone maintenance is an effective replacement therapy to treat heroin addiction, which significantly reduces the relapse rate. The present study examines whether the patients with opioid use disorder on chronic methadone maintenance therapy exhibit abnormal attentional bias to drug cues and negative-affective cues. Moreover, its relation to therapeutic and neuropsychological factors is also examined. Methods: Seventy-nine patients with opioid use disorder under chronic methadone maintenance therapy and 73 age-, sex-, and education-matched healthy controls were recruited and assessed for attentional bias to drug cues and negative affect using a dot-probe detection task. Correlational analysis was used to examine the relationships between the attentional bias and the demographic, therapeutic, and neuropsychological factors. Results: No significant overall patient-control group difference is observed in drug-related or negative-affective-related attentional bias scores. In the patient group, however, a significant negative correlation is found between the attentional bias scores to negative-affective cues and the duration of methadone treatment (p = 0.027), with the patients receiving longer methadone treatment showing less attentional avoidance to negative-affective cues. A significant positive correlation is found between the negative affect-induced bias and the impulsivity score (p = 0.006), with more impulsive patients showing higher attentional avoidance to negative affective cues than less impulsive patients. Additionally, the patients detect a smaller percentage of probe stimuli following the drug (p = 0.029) or negative-affective pictures (p = 0.009) than the healthy controls. Conclusion: The results of the present study indicate that the patients under chronic methadone maintenance therapy show normalized attentional bias to drug and negative-affective cues, confirming the involuntary attention of the patients is not abnormally captured by external drug or negative-affective clues. Our findings also highlight that the attentional avoidance of negative-affective cues is modulated by the duration of methadone treatment and the impulsivity level in the patients.

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.

Epitope specificity of two anti-morphine monoclonal antibodies: In vitro and in silico studies

Monoclonal antibodies (mAbs) against morphine are important in the development of immunotherapeutic and diagnostic methods for the treatment and prevention of drug addiction. By the surface plasmon resonance (SPR) and enzyme immunoassay techniques, we characterized two previously obtained mAbs 3K11 and 6G1 and showed their ability to recognize free morphine and morphine-containing antigens in different ways because of the epitope specificity thereof. Using the defined amino acid sequences, we obtained three-dimensional models of the variable regions of Fab fragments of these antibodies and compared them with the known sequence and spatial structure of the anti-morphine antibody 9B1. Docking simulations are performed to obtain models of the antibodies complexes with morphine. Differences in the models of 3K11 and 6G1 complexes with morphine correlate with their experimentally detected epitope specificity. The results, in particular, can be used for the structure-based design of the corresponding humanized antibodies. According to our modeling and docking results, the very different modes of morphine binding to mAbs 3K11 and 6G1 are qualitatively similar to those previously reported for cocaine and two anti-cocaine antibodies. Thus, the obtained structural information brings more insight into the hapten recognition diversity.

Structural analysis of free and liganded forms of the Fab fragment of a high-affinity anti-cocaine antibody, h2E2

A high-affinity anti-cocaine monoclonal antibody, designated h2E2, is entering phase 1 clinical trials for cocaine abuse therapy. To gain insight into the molecular details of its structure that are important for binding cocaine and cocaine metabolites, the Fab fragment was generated and crystallized with and without ligand. Structures of the unliganded Fab and the Fab fragment bound to benzoylecgonine were determined, and were compared with each other and with other crystallized anti-cocaine antibodies. The affinity of the h2E2 antibody for cocaine is 4 nM, while that of the cocaine metabolite benzoylecgonine is 20 nM. Both are higher than the reported affinity for cocaine of the two previously crystallized anti-cocaine antibodies. Consistent with cocaine fluorescent quenching binding studies for the h2E2 mAb, four aromatic residues in the CDR regions of the Fab (TyrL32, TyrL96, TrpL91 and TrpH33) were found to be involved in ligand binding. The aromatic side chains surround and trap the tropane moiety of the ligand in the complex structure, forming significant van der Waals interactions which may account for the higher affinity observed for the h2E2 antibody. A water molecule mediates hydrogen bonding between the antibody and the carbonyl group of the benzoyl ester. The affinity of binding to h2E2 of benzoylecgonine differs only by a factor of five compared with that of cocaine; therefore, it is suggested that h2E2 would bind cocaine in the same way as observed in the Fab-benzoylecgonine complex, with minor rearrangements of some hypervariable segments of the antibody.

A Recombinant Humanized Anticocaine Monoclonal Antibody Alters the Urinary Clearance of Cocaine and Its Metabolites in Rats

A recombinant humanized anticocaine monoclonal antibody, h2E2, has shown potential in the preclinical phases for the treatment of cocaine abuse. The standard tests for cocaine usage are the detection of benzoylecgonine (BE) and cocaine in the urine. This includes workplace drug screens as well as in clinical trials for potential treatments of cocaine abuse. By sequestering cocaine into the plasma compartment, h2E2 prevents cocaine from entering the brain. Due to the altered disposition of cocaine in the presence of h2E2, we investigated the effects of h2E2 on cocaine and metabolite levels in the urine of rats to clarify the use of BE as an endpoint measurement for effectiveness in future clinical trials. The urine concentrations of cocaine and metabolites were considerably altered in the presence of h2E2. After a single injection of h2E2 (120 mg/kg) and cocaine hydrochloride (0.56 mg/kg), the concentration of cocaine and BE excreted into the urine of rats decreased by 92% and 91%, respectively, from vehicle controls. Due to the significant decrease in urinary excretion, BE is not an appropriate indicator of cocaine usage in the presence of h2E2. Another endpoint measurement must be selected for the measurement of cocaine usage in the upcoming clinical trials of h2E2. In contrast to the effects on cocaine and BE urinary excretion, there was a 3-fold increase in ecgonine methyl ester (EME) in the presence of h2E2. Therefore, we conclude that EME is a more appropriate measurement of cocaine intake in the presence of h2E2.

Domain unfolding of monoclonal antibody fragments revealed by non-reducing SDS-PAGE

Monoclonal antibodies and derived fragments are used extensively both experimentally and therapeutically. Thorough characterization of such antibodies is necessary and includes assessment of their thermal and storage stabilities. Thus, assessment of the underlying conformational stabilities of the antibodies is also important. We recently documented that non-reducing SDS-PAGE can be used to assess both monoclonal and polyclonal IgG domain thermal unfolding in SDS. Utilizing this same h2E2 anti-cocaine mAb, in this study we generated and analyzed various mAb antibody fragments to delineate the structural domains of the antibody responsible for the observed discrete bands following various heating protocols and analysis by non-reducing SDS-PAGE. Previously, these domain unfolding transitions and gel bands were hypothesized to stem from known mAb structural domains based on the relative thermal stability of those CH2, CH3, and Fab domains in the absence of SDS, as measured by differential scanning calorimetry. In this study, we generated and analyzed F(ab’)₂, Fab, and Fc fragments, as well as a mAb consisting of only heavy chains, and examined the thermally induced domain unfolding in each of these fragments by non-reducing SDS-PAGE. The results were interpreted and integrated to generate an improved model of thermal unfolding for the mAb IgG in SDS. These results and the model presented should be generally applicable to many monoclonal and polyclonal antibodies and allow novel comparisons of conformational stabilities between chemically or genetically modified versions of a given antibody. Such modified antibodies and antibody drug conjugates are commonly utilized and important for experimental and therapeutic applications.

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mAb F(ab’)₂ fragments exhibit multiple unfolded states in non-reducing SDS-PAGE.

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Fab and Fc mAb fragments do not exhibit similar multiple unfolded state bands.

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Previous mAb domain unfolding pathway in SDS is revised based on fragment analyses.

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A heavy chain only mAb variant is detected and exhibits multiple unfolded states.

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These results are likely relevant to analyses of many monoclonal and polyclonal Abs.

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.

A Stable Heroin Analogue That Can Serve as a Vaccine Hapten to Induce Antibodies That Block the Effects of Heroin and Its Metabolites in Rodents and That Cross-React Immunologically with Related Drugs of Abuse

An improved synthesis of a haptenic heroin surrogate 1 (6-AmHap) is reported. The intermediate needed for the preparation of 1 was described in the route in the synthesis of 2 (DiAmHap). A scalable procedure was developed to install the C-3 amido group. Using the Boc protectng group in 18 allowed preparation of 1 in an overall yield of 53% from 4 and eliminated the necessity of preparing the diamide 13. Hapten 1 was conjugated to tetanus toxoid and mixed with liposomes containing monophosphoryl lipid A as an adjuvant. The 1 vaccine induced high anti-1 IgG levels that reduced heroin-induced antinociception and locomotive behavioral changes following repeated subcutaneous and intravenous heroin challenges in mice and rats. Vaccinated mice had reduced heroin-induced hyperlocomotion following a 50 mg/kg heroin challenge. The 1 vaccine-induced antibodies bound to heroin and other abused opioids, including hydrocodone, oxycodone, hydromorphone, oxymorphone, and codeine.

Cross-reactivity of selected benzofurans with commercial amphetamine and ecstasy immunoassays in urine

Aim: The aim of this study was to perform a cross-reactivity investigation of six benzofurans with immunoassays (IAs) screening tests for amphetamines and ecstasy in urine samples. Methods: The following benzofuranes were investigated: 5-(2-Methylaminopropyl)Benzofuran (5-MAPB), 5-(2-methylaminopropyl)-2,3-dihydrobenzofuran (5-MAPDB), 5-(2-Aminopropyl)-Benzofuran (5-APB), 5-(2-Aminopropyl)-2,3-dihydrobenzofuran (5-APDB), 5-(2-Ethylaminopropyl)Benzofuran (5-EAPB) and 5-(2-Aminoethyl)-2,3-dihydrobenzofuran (5-AEDB). The study was performed with urine-free spiked samples and authentic urine samples using eight different IAs for amphetamines and ecstasy. Results: All evaluated benzofurans showed cross-reactivity in some of the IAs tested, except for 5-AEDB. Urine samples of an intoxication case involving 5-MAPB, 5-APB and 5-EAPB were also positives in the IAs tested. Conclusion: There is an important variability in the cross-reactivity of the IAs for amphetamine and ecstasy caused by benzofurans depending on the immunoassay employed and the tested compounds.

A naturalistic longitudinal analysis of post-detoxification outcomes in opioid-dependent patients

INTRODUCTION AND AIMS

To provide an assessment of outcomes in a cohort of opioid-dependent patients post-detoxification.

DESIGN AND METHODS

This study employed an observational longitudinal cohort design. Patients who completed detoxification in the three major Drug Dependency Units in Ireland during a 14-month period were included in the study (n = 143). Patients opting for one of the three pathways post-detoxification (inpatient aftercare, outpatient aftercare or no formal aftercare) were assessed in the final week of detoxification and followed up after 3, 6 and 9 months. The primary outcome was abstinence following detoxification.

RESULTS

A Cox (adjusted) model indicated participants who opted for outpatient aftercare treatment lapsed/relapsed at a rate of 52% higher than the inpatient aftercare group (hazard ratio = 1.52, 95% confidence interval 0.75-3.08, P = 0.24). Moreover, time to lapse/relapse was considerably shorter for the no formal aftercare group (hazard ratio = 7.68, 95% confidence interval 4.30-13.73, P = 5.75 × 10^-12 ). Abstinence rates for outpatient aftercare and inpatient aftercare are about equal after 9 months.

DISCUSSION AND CONCLUSION

Patients who opt for aftercare post-detoxification have significantly better outcomes at follow up when compared to no formal aftercare. In addition, patients' intention to attend aftercare affected their outcomes regardless of eventual treatment path.

A mathematical model of a recombinant humanized anti-cocaine monoclonal antibody's effects on cocaine pharmacokinetics in mice

AIMS

A recombinant humanized anti-cocaine monoclonal antibody (mAb), h2E2, is at an advanced stage of pre-clinical development as an immunotherapy for cocaine abuse. It is hypothesized that h2E2 binds to and sequesters cocaine in the blood.

MAIN METHODS

A three-compartment model of the effects of h2E2 on cocaine's distribution was constructed. The model assumes that h2E2 binds to cocaine and that the h2E2-cocaine complex does not enter the brain but distributes between the central and peripheral compartments. Free cocaine is eliminated from both the central and peripheral compartments, and h2E2 and the h2E2-cocaine complex are eliminated from the central compartment only. This model was tested against a new dataset measuring cocaine concentrations in the brain and plasma over 1h in the presence and absence of h2E2.

KEY FINDINGS

The mAb significantly increased plasma cocaine concentrations with a concomitant significant decrease in brain concentration. Plasma concentrations declined over the 1-hour sampling period in both groups. With a set of parameters within reasonable physiological ranges, the three-compartment model was able to qualitatively and quantitatively simulate the increased plasma concentration in the presence of the antibody and the decreased peak brain concentration in the presence of antibody. Importantly, the model explained the decline in plasma concentrations over time as distribution of the cocaine-h2E2 complex into a peripheral compartment.

SIGNIFICANCE

This model will facilitate the targeting of ideal mAb PK/PD properties thus accelerating the identification of lead candidate anti-drug mAbs.

Recombinant Adeno-Associated Virus-Mediated Expression of Methamphetamine Antibody Attenuates Methamphetamine-Induced Hyperactivity in Mice

Methamphetamine (Meth) is one of the most frequently abused drugs worldwide. Recent studies have indicated that antibodies with high affinity for Meth reduce its pharmacological effects. The purpose of this study was to develop a technique for virus-based passive immunization against Meth effects. We generated a recombinant adeno-associated virus serotype-8 vector (AAV-MethAb) carrying the gene for a Meth-specific monoclonal antibody (MethAb). Infection of 293 cells with AAV-MethAb resulted in the expression and secretion of antibodies which bind to Meth. The viral vector was then examined in adult ICR mice. Systemic administration of AAV-MethAb resulted in long-term expression of MethAb in the serum for up to 29 weeks. Serum collected from the animals receiving AAV-MethAb retained a high specificity for (+)-Meth. Animals were challenged with Meth five weeks after viral injection. Meth levels in the brain and serum were reduced while Meth-induced locomotor activity was significantly attenuated. In conclusion, AAV-MethAb administration effectively depletes Meth from brain and serum while reducing the behavioral response to Meth, and thus is a potential therapeutic approach for Meth abuse.

Lifestyle Vaccines and Public Health: Exploring Policy Options for a Vaccine to Stop Smoking

Experimental vaccines are being developed for the treatment of 'unhealthy lifestyles' and associated chronic illnesses. Policymakers and other stakeholders will have to deal with the ethical issues that this innovation path raises: are there morally justified reasons to integrate these innovative biotechnologies in future health policies? Should public money be invested in further research? Focusing on the case of an experimental nicotine vaccine, this article explores the ethical aspects of 'lifestyle vaccines' for public health. Based on findings from a qualitative study into a vaccine for smoking cessation, the article articulates possible value conflicts related to nicotine vaccination as an intervention in tobacco control. The 'vaccinization' of lifestyle disease piggybacks on the achievements of classic vaccines. Contrary to expectations of simplicity and success, quitting smoking with a vaccine requires a complex supportive network. Social justice and public trust may become important ethical challenges when deciding whether to use further public funds for research or whether to implement these innovative vaccines in the future.

Pharmacological Effects of a Monoclonal Antibody against 6-Monoacetylmorphine upon Heroin-Induced Locomotor Activity and Pharmacokinetics in Mice

Immunotherapy can provide a supplemental treatment strategy against heroin use on the principle of sequestering the active drug in the bloodstream, thereby reducing its distribution to the brain. Previous studies have shown that heroin's first metabolite, 6-monoacetylmorphine (6-MAM), is the main mediator of acute heroin effects. The objective of the present study was to characterize the pharmacological potential of a monoclonal antibody against 6-MAM (anti-6-MAM mAb) to counteract the heroin response. The individual contributions from heroin and 6-MAM to heroin effects were also examined by pretreating mice with anti-6-MAM mAb (10-100 mg/kg) prior to either heroin or 6-MAM injection (1.25-2.5 μmol/kg). The opioid-induced behavioral response was assessed in a locomotor activity test, followed by opioid and antibody quantification in blood and brain tissue. Pretreatment with mAb caused a profound reduction of heroin- and 6-MAM-induced behavior, accompanied by correspondingly decreased levels of 6-MAM in brain tissue. mAb pretreatment was more efficient against 6-MAM injection than against heroin, leading to an almost complete blockade of 6-MAM-induced effects. mAb pretreatment was unable to block the immediate (5-minute) transport of active metabolites across the blood-brain barrier after heroin injection, indicating that heroin itself appears to enhance the immediate delivery of 6-MAM to the brain. The current study provides additional evidence that 6-MAM sequestration is crucial for counteracting the acute heroin response, and demonstrates the pharmacological potential of immunotherapy against heroin use.

Identification of Treatment Targets in a Genetic Mouse Model of Voluntary Methamphetamine Drinking

Methamphetamine has powerful stimulant and euphoric effects that are experienced as rewarding and encourage use. Methamphetamine addiction is associated with debilitating illnesses, destroyed relationships, child neglect, violence, and crime; but after many years of research, broadly effective medications have not been identified. Individual differences that may impact not only risk for developing a methamphetamine use disorder but also affect treatment response have not been fully considered. Human studies have identified candidate genes that may be relevant, but lack of control over drug history, the common use or coabuse of multiple addictive drugs, and restrictions on the types of data that can be collected in humans are barriers to progress. To overcome some of these issues, a genetic animal model comprised of lines of mice selectively bred for high and low voluntary methamphetamine intake was developed to identify risk and protective alleles for methamphetamine consumption, and identify therapeutic targets. The mu opioid receptor gene was supported as a target for genes within a top-ranked transcription factor network associated with level of methamphetamine intake. In addition, mice that consume high levels of methamphetamine were found to possess a nonfunctional form of the trace amine-associated receptor 1 (TAAR1). The Taar1 gene is within a mouse chromosome 10 quantitative trait locus for methamphetamine consumption, and TAAR1 function determines sensitivity to aversive effects of methamphetamine that may curb intake. The genes, gene interaction partners, and protein products identified in this genetic mouse model represent treatment target candidates for methamphetamine addiction.

Critical needs in drug discovery for cessation of alcohol and nicotine polysubstance abuse

Polysubstance abuse of alcohol and nicotine has been overlooked in our understanding of the neurobiology of addiction and especially in the development of novel therapeutics for its treatment. Estimates show that as many as 92% of people with alcohol use disorders also smoke tobacco. The health risks associated with both excessive alcohol consumption and tobacco smoking create an urgent biomedical need for the discovery of effective cessation treatments, as opposed to current approaches that attempt to independently treat each abused agent. The lack of treatment approaches for alcohol and nicotine abuse/dependence mirrors a similar lack of research in the neurobiology of polysubstance abuse. This review discusses three critical needs in medications development for alcohol and nicotine co-abuse: (1) the need for a better understanding of the clinical condition (i.e. alcohol and nicotine polysubstance abuse), (2) the need to better understand how these drugs interact in order to identify new targets for therapeutic development and (3) the need for animal models that better mimic this human condition. Current and emerging treatments available for the cessation of each drug and their mechanisms of action are discussed within this context followed by what is known about the pharmacological interactions of alcohol and nicotine. Much has been and will continue to be gained from studying comorbid alcohol and nicotine exposure.

Is immunotherapy an opportunity for effective treatment of drug addiction?

Immunotherapy has a great potential of becoming a new therapeutic strategy in the treatment of addiction to psychoactive drugs. It may be used to treat addiction but also to prevent neurotoxic complications of drug overdose. In preclinical studies two immunological methods have been tested; active immunization, which relies on the administration of vaccines and passive immunization, which relies on the administration of monoclonal antibodies. Until now researchers have succeeded in developing vaccines and/or antibodies against addiction to heroin, cocaine, methamphetamine, nicotine and phencyclidine. Their effectiveness has been confirmed in preclinical studies. At present, clinical studies are being conducted for vaccines against nicotine and cocaine and also anti-methamphetamine monoclonal antibody. These preclinical and clinical studies suggest that immunotherapy may be useful in the treatment of addiction and drug overdose. However, there are a few problems to be solved. One of them is controlling the level of antibodies due to variability between subjects. But even obtaining a suitable antibody titer does not guarantee the effectiveness of the vaccine. Additionally, there is a risk of intentional or unintentional overdose. As vaccines prevent passing of drugs through the blood/brain barrier and thereby prevent their positive reinforcement, some addicted patients may erroneously seek higher doses of psychoactive substances to get "high". Consequently, vaccination should be targeted at persons who have a strong motivation to free themselves from drug dependency. It seems that immunotherapy may be an opportunity for effective treatment of drug addiction if directed to adequate candidates for treatment. For other addicts, immunotherapy may be a very important element supporting psycho- and pharmacotherapy.

A conjugate vaccine attenuates morphine- and heroin-induced behavior in rats

BACKGROUND

Currently approved medications for opioid addiction have shown clinical efficacy, but undesired side effects, dependence induced by the medications themselves, and low treatment compliance necessitate the need for novel therapies.

METHODS

A novel morphine-keyhole limpet hemocyanin conjugate vaccine was synthesized with 6-glutarylmorphine as the hapten and a lengthened linker of 6 carbon atoms. The titer and specificity of the triggered antibody were assessed by enzyme-linked immunosorbent assay. The effects of the vaccine on the morphine-induced elevation of dopamine levels in the nucleus accumbens were determined by high-performance liquid chromatography. The effects of the vaccine on morphine-induced locomotor sensitization and heroin-primed reinstatement of heroin self-administration were also assessed.

RESULTS

After subcutaneous administration in rats, the vaccine triggered a high antibody titer, with comparable specificity for morphine, 6-acetylmorphine, and heroin, but no interaction with dissimilar therapeutic opioid compounds, including buprenorphine, naloxone, and nalorphine, was observed. The vaccine significantly prevented the elevation of dopamine levels in the nucleus accumbens induced by a single morphine challenge. Moreover, the vaccine prevented the expression of morphine-induced locomotor sensitization and heroin-primed reinstatement of heroin seeking, suggesting its potential for preventing relapse.

CONCLUSION

These results demonstrate that active immunization with the present vaccine induces a robust morphine/heroin-specific antibody response in rats and attenuates the behavioral effects of morphine and heroin.

Vaccines against stimulants: cocaine and MA

While the worldwide prevalence of cocaine use remains significant, medications, or small molecule approaches, to treat drug addictions have met with limited success. Anti-addiction vaccines, on the other hand, have demonstrated great potential for treating drug abuse using a distinctly different mechanism of eliciting an antibody response that blocks the pharmacological effects of drugs. We provide a review of vaccine-based approaches to treating stimulant addictions; specifically and cocaine addictions. This selective review article focuses on the one cocaine vaccine that has been into clinical trials and presents new data related to pre-clinical development of a methamphetamine (MA) vaccine. We also review the mechanism of action for vaccine induced antibodies to abused drugs, which involves kinetic slowing of brain entry as well as simple blocking properties. We present pre-clinical innovations for MA vaccines including hapten design, linkage to carrier proteins and new adjuvants beyond alum. We provide some new information on hapten structures and linkers and variations in protein carriers. We consider a carrier, outer membrance polysaccharide coat protein (OMPC), that provides some self-adjuvant through lipopolysaccharide components and provide new results with a monophosopholipid adjuvant for the more standard carrier proteins with cocaine and MA. The review then covers the clinical trials with the cocaine vaccine TA-CD. The clinical prospects for advances in this field over the next few years include a multi-site cocaine vaccine clinical trial to be reported in 2013 and phase 1 clinical trials of a MA vaccine in 2014.

Vaccination against smoking: an annotated agenda for debate. A review of scientific journals, 2001-13

BACKGROUND AND AIMS

The ongoing development of novel nicotine vaccines makes it urgent to identify the normative questions around this innovative health technology against smoking.

METHODS

A qualitative thematic analysis of peer-reviewed papers on nicotine vaccination published between 2001 and 2013.

RESULTS

In the scientific discourse, nicotine vaccination is presented in a neurobiological frame as a potent concept for (long-term) smoking cessation. Nicotine vaccination is also considered a hypothetical strategy to prevent nicotine addiction in minors. Ethical assessments are conducted for the use of nicotine vaccination in public health and clinical medicine. Whereas vaccination for primary prevention is usually associated with public health, the hypothetical case of nicotine prevention in minors is also assessed for individualized protection. Therapeutic and preventive applications are given uneven attention: the classic goal of vaccination (primary prevention in minors) receives methodical consideration and invokes lively debate. The unprecedented use of vaccination, namely smoking cessation, is left largely unattended in the ethical analyses.

CONCLUSIONS

While health innovations such as nicotine vaccination need broad reflection to guide decisions on their further development and possible future implementations, only a small part of the ethical and social issues of this innovative technology has been discussed. For a debate to come into existence, a 'neurobio-psycho-socio-cultural' frame of smoking and quitting appears fruitful. Important topics for reflection are the human activities and social processes in a vaccine-supported quit attempt, next to respect for individuals, possible harms and questions of (global) justice and research ethics.

Suppression of nicotine-induced pathophysiology by an adenovirus hexon-based antinicotine vaccine

Despite antismoking campaigns, cigarette smoking remains a pervasive addiction with significant societal impact, accounting for one of every five deaths. Smoking cessation therapies to help smokers quit are ineffective with a high recidivism rate. With the knowledge that nicotine is the principal addictive compound of cigarettes, we have developed an antismoking vaccine based on the highly immunogenic properties of the hexon protein purified from the serotype 5 adenovirus (Ad) capsid. We hypothesized that an effective antinicotine vaccine could be based on coupling the nicotine hapten AM1 to purified Ad hexon protein. To assess this, AM1 was conjugated to hexon purified from serotype 5 Ad to produce the HexonAM1 vaccine. C57Bl/6 mice were sensitized by 10 daily nicotine administrations (0.5 mg/kg, subcutaneous) to render the mice addicted to nicotine. Control groups were sensitized to phosphate-buffered saline (PBS). The mice were then immunized with HexonAM1 (4 μg, intramuscular) at 0, 3, and 6 weeks. By 6 weeks, the HexonAM1-vaccinated mice had serum antinicotine antibody titers of 1.1×10(6)±7.6×10(4). To demonstrate that these high antinicotine titers were sufficient to suppress the effects of nicotine, HexonAM1-vaccinated mice were evaluated for nicotine-induced hypoactive behavior with nicotine challenges (0.5 mg/kg wt) over 5 weeks. In all challenges, the HexonAM1-vaccinated mice behaved similar to PBS-challenged naive mice. These data demonstrate that a vaccine comprised of a nicotine analog coupled to Ad hexon can evoke a high level of antinicotine antibodies sufficient to inhibit nicotine-induced behavior. The HexonAM1 vaccine represents a platform paradigm for vaccines against small molecules.

A recombinant humanized anti-cocaine monoclonal antibody inhibits the distribution of cocaine to the brain in rats

The monoclonal antibody (mAb), h2E2, is a humanized version of the chimeric human/murine anti-cocaine mAb 2E2. The recombinant h2E2 protein was produced in vitro from a transfected mammalian cell line and retained high affinity (4 nM Kd) and specificity for cocaine over its inactive metabolites benzoylecgonine (BE) and ecgonine methyl ester. In rats, pharmacokinetic studies of h2E2 (120 mg/kg i.v.) showed a long terminal elimination half-life of 9.0 days and a low volume of distribution at steady state (Vdss) of 0.3 l/kg. Pretreatment with h2E2 produced a dramatic 8.8-fold increase in the area under the plasma cocaine concentration-time curve (AUC) and in brain a concomitant decrease of 68% of cocaine's AUC following an i.v. injection of an equimolar cocaine dose. Sequestration of cocaine in plasma by h2E2, shown via reduction of cocaine's Vdss, indicates potential clinical efficacy. Although the binding of cocaine to h2E2 in plasma should inhibit distribution and metabolism, the elimination of cocaine remained multicompartmental and was still rapidly eliminated from plasma despite the presence of h2E2. BE was the major cocaine metabolite, and brain BE concentrations were sixfold higher than in plasma, indicating that cocaine is normally metabolized in the brain. In the presence of h2E2, brain BE concentrations were decreased and plasma BE was increased, consistent with the observed h2E2-induced changes in cocaine disposition. The inhibition of cocaine distribution to the brain confirms the humanized mAb, h2E2, as a lead candidate for development as an immunotherapy for cocaine abuse.

A monoclonal antibody specific for 6-monoacetylmorphine reduces acute heroin effects in mice

Immunotherapy against drugs of abuse is being studied as an alternative treatment option in addiction medicine and is based on antibodies sequestering the drug in the bloodstream and blocking its entry into the brain. Producing an efficient vaccine against heroin has been considered particularly challenging because of the rapid metabolism of heroin to multiple psychoactive molecules. We have previously reported that heroin's first metabolite, 6-monoacetylmorphine (6-MAM), is the predominant mediator for heroin's acute behavioral effects and that heroin is metabolized to 6-MAM primarily prior to brain entry. On this basis, we hypothesized that antibody sequestration of 6-MAM is sufficient to impair heroin-induced effects and therefore examined the effects of a monoclonal antibody (mAb) specific for 6-MAM. In vitro experiments in human and rat blood revealed that the antibody was able to bind 6-MAM and block the metabolism to morphine almost completely, whereas the conversion of heroin to 6-MAM remained unaffected. Mice pretreated with the mAb toward 6-MAM displayed a reduction in heroin-induced locomotor activity that corresponded closely to the reduction in brain 6-MAM levels. Intraperitoneal and intravenous administration of the anti-6-MAM mAb gave equivalent protection against heroin effects, and the mAb was estimated to have a functional half-life of 8 to 9 days in mice. Our study implies that an antibody against 6-MAM is effective in counteracting heroin effects.

Customizing monoclonal antibodies for the treatment of methamphetamine abuse: current and future applications

Monoclonal antibody-based medications designed to bind (+)-methamphetamine (METH) with high affinity are among the newest approaches to the treatment of METH abuse and the associated medical complications. The potential clinical indications for these medications include treatment of overdose, reduction of drug dependence, and protection of vulnerable populations from METH-related complications. Research designed to discover and conduct preclinical and clinical testing of these antibodies suggests a scientific vision for how intact monoclonal antibody (mAb) (singular and plural) or small antigen-binding fragments of mAb could be engineered to optimize the proteins for specific therapeutic applications. In this review, we discuss keys to success in this development process including choosing predictors of specificity, efficacy, duration of action, and safety of the medications in disease models of acute and chronic drug abuse. We consider important aspects of METH-like hapten design and how hapten structural features influence specificity and affinity, with an example of a high-resolution X-ray crystal structure of a high-affinity antibody to demonstrate this structural relationship. Additionally, several prototype anti-METH mAb forms such as antigen-binding fragments and single-chain variable fragments are under development. Unique, customizable aspects of these fragments are presented with specific possible clinical indications. Finally, we discuss clinical trial progress of the first in kind anti-METH mAb, for which METH is the disease target instead of vulnerable central nervous system networks of receptors, binding sites, and neuronal connections.

Structural characterization of a therapeutic anti-methamphetamine antibody fragment: oligomerization and binding of active metabolites

Vaccines and monoclonal antibodies (mAb) for treatment of (+)-methamphetamine (METH) abuse are in late stage preclinical and early clinical trial phases, respectively. These immunotherapies work as pharmacokinetic antagonists, sequestering METH and its metabolites away from sites of action in the brain and reduce the rewarding and toxic effects of the drug. A key aspect of these immunotherapy strategies is the understanding of the subtle molecular interactions important for generating antibodies with high affinity and specificity for METH. We previously determined crystal structures of a high affinity anti-METH therapeutic single chain antibody fragment (scFv6H4, K_D = 10 nM) in complex with METH and the (+) stereoisomer of 3,4-methylenedioxymethamphetamine (MDMA, or “ecstasy”). Here we report the crystal structure of scFv6H4 in homo-trimeric unbound (apo) form (2.60Å), as well as monomeric forms in complex with two active metabolites; (+)-amphetamine (AMP, 2.38Å) and (+)-4-hydroxy methamphetamine (p-OH-METH, 2.33Å). The apo structure forms a trimer in the crystal lattice and it results in the formation of an intermolecular composite beta-sheet with a three-fold symmetry. We were also able to structurally characterize the coordination of the His-tags with Ni²⁺. Two of the histidine residues of each C-terminal His-tag interact with Ni²⁺ in an octahedral geometry. In the apo state the CDR loops of scFv6H4 form an open conformation of the binding pocket. Upon ligand binding, the CDR loops adopt a closed formation, encasing the drug almost completely. The structural information reported here elucidates key molecular interactions important in anti-methamphetamine abuse immunotherapy.

Treatment of methamphetamine abuse: an antibody-based immunotherapy approach

Methamphetamine is a highly addictive psychostimulant with tens of millions of abusers around the world, and currently there is no effective or approved medication for addiction to it. Monoclonal antibodies with a high affinity for methamphetamine have the potential to sequester the drug in the vascular compartment and reduce entry into the brain, acting as peripheral pharmacokinetic antagonists without inducing adverse effects on neurons. However, in order to maintain the antibodies at an effective level, repeated administration is required, which would be expensive and problematic for patient compliance. In this study, we intended to investigate whether using a recombinant adeno-associated virus-mediated gene transfer technique can be an effective approach to achieve long-term expression of anti-methamphetamine monoclonal antibodies in mouse models. We generated a recombinant adeno-associated virus vector encoding the heavy and light chains of an anti-methamphetamine monoclonal antibody, which were constructed in a single open reading frame and linked with a 2A self-processing sequence. In the context of virus-mediated gene transfer, expression of full-length and functional monoclonal antibodies was successfully demonstrated in vitro and in vivo. Further investigations on dose optimization, long-term expression, and protection from methamphetamine challenge in mouse models are ongoing.

Liposomes containing monophosphoryl lipid A: a potent adjuvant system for inducing antibodies to heroin hapten analogs

In order to create an effective immunization approach for a potential vaccine to heroin, liposomes containing monophosphoryl lipid A [L(MPLA)] were tested as an adjuvant system to induce antibodies to heroin hapten analogs. Four synthetic haptens and two immunization strategies were employed. In the first strategy, a hydrophobic 23 amino acid immunogenic peptide derived from the membrane proximal external region of gp41 from HIV-1 envelope protein was embedded as a carrier in the outer surface of L(MPLA), to which was conjugated a 15 amino acid universal T cell epitope and a terminal heroin hapten analog. In the second strategy, tetanus toxoid (TT) carrier protein was decorated with haptens by conjugation, and the hapten-conjugated protein was mixed with L(MPLA). After immunization of mice, each of the immunization strategies was effective for induction of IgG anti-hapten antibodies. The first immunization strategy induced a mean end-point IgG titer against one of two haptens tested of approximately 12,800; however, no detectable antibodies were induced against the liposome-associated HIV-1 carrier peptide. In the second immunization strategy, depending on the hapten used for decorating the TT, end-point IgG titers ranged from 100,000 to 6,500,000. In this strategy, in which hapten was conjugated to the TT, end-point IgG titers of 400,000 to the TT carrier were observed with each conjugate. However, upon mixing unconjugated TT with L(MPLA), anti-TT titers of 6,500,000 were observed. We conclude that L(MPLA) serves as a potent adjuvant for inducing antibodies to candidate heroin haptens. However, antibodies to the carrier peptide or protein were partly or completed inhibited by the presence of conjugated hapten.

Cloning and characterization of a hybridoma secreting a 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-specific monoclonal antibody and recombinant F(ab)

Smokeless tobacco products have been associated with increased risks of oro-pharyngeal cancers, due in part to the presence of tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These potent carcinogens are formed during tobacco curing and as a result of direct nitrosation reactions that occur in the oral cavity. In the current work we describe the isolation and characterization of a hybridoma secreting a high-affinity, NNK-specific monoclonal antibody. A structurally-related benzoyl derivative was synthesized to facilitate coupling to NNK-carrier proteins, which were characterized for the presence of the N-nitroso group using the Griess reaction, and used to immunize BALB/c mice. Splenocytes from mice bearing NNK-specific antibodies were used to create hybridomas. Out of four, one was selected for subcloning and characterization. Approximately 99% of the monoclonal antibodies from this clone were competitively displaced from plate-bound NNKB conjugates in the presence of free NNK. The affinity of the monoclonal antibody to the NNKB conjugates was Kd = 2.93 nM as determined by surface plasmon resonance. Free nicotine was a poor competitor for the NNKB binding site. The heavy and light chain antibody F(ab) fragments were cloned, sequenced and inserted in tandem into an expression vector, with an FMDV Furin 2A cleavage site between them. Expression in HEK 293 cells revealed a functional F(ab) with similar binding features to that of the parent hybridoma. This study lays the groundwork for synthesizing transgenic tobacco that expresses carcinogen-sequestration properties, thereby rendering it less harmful to consumers.

Ethical implications of research on craving

Cravings, intense desires to experience the effects of a drug, are widely regarded as significant impediments to overcoming addiction, although their role in relapse may be overstated. Scientists and clinicians wish to better understand the neurobiological and cognitive basis of craving so that they may develop psychotherapeutic, pharmacological and other medical methods to reduce craving and thereby drug use. The conduct of such research raises significant ethical issues. When recruiting individuals and conducting this research, scientists need to ensure that substance dependent participants have the capacity to provide free and uncoerced consent. This is especially the case in studies in which dependent participants are given their drug of addiction or provided with other inducements to participate (e.g. financial incentives) that may undermine their ability to fully consider the risks of participation. Treatments for addiction that seek to reduce cravings may also carry risks. This includes psychotherapeutic approaches, as well as pharmacological and medical treatments. Clinicians need to consider the risks and benefits of treatment and carefully communicate these to patients. The desire to reduce urges to use drugs should not be employed to justify potentially harmful and ineffective treatments. The safety and effectiveness of emerging treatments should be assessed by well conducted randomized controlled clinical trials.

Medications for substance use disorders

In this article, the authors briefly review the pharmacotherapeutic agents that are currently available for the treatment of substance use disorders. Nicotine replacement therapies are most effective for tobacco cessation. Naltrexone, acamprosate, and disulfiram are effective for reducing alcohol use. The most effective pharmacotherapies for opiate use disorders are agonist therapies, including methadone and buprenorphine. The authors also examine recent advances in medication development for other substance use disorders such as stimulant addiction. The role of medication adherence and behavioral treatments and the integration of behavioral and pharmacotherapeutic interventions are also discussed.

Interception of cocaine by enzyme or antibody delivered with viral gene transfer: a novel strategy for preventing relapse in recovering drug users

Recent progress in enzyme engineering has led to versions of human butyrylcholinesterase (BChE) that hydrolyze cocaine efficiently in plasma, reduce concentrations reaching reward neurocircuity in the brain, and weaken behavioral responses to this drug. Along with enzyme advances, increasingly avid anti-cocaine antibodies and potent anti-cocaine vaccines have also been developed. Here we review these developments and consider the potential advantages along with the risks of delivering drug-intercepting proteins via gene transfer approaches to treat cocaine addiction.

Monoclonal antibodies as pharmacokinetic antagonists for the treatment of (+)-methamphetamine addiction

Developing specific medications to treat (+)-methamphetamine (METH) addiction is a difficult challenge because METH has multiple sites of action that are intertwined with normal neurological function. As a result, no small molecule medication for the treatment of METH addiction has made it through the FDA clinical trials process. With the invention of a new generation of proteinbased therapies, it is now possible to consider treating drug addiction by an entirely different approach. This new approach is based on the discovery of very high affinity anti-METH monoclonal antibodies (mAbs), which are non-addictive and antagonize METH effects from the blood stream without entering the brain. Due to a very long biological half-life, anti-METH mAbs would only need to be administered once every 2-4 weeks, aiding in patient compliance. As a relapse prevention medication, anti-METH mAbs could reduce or prevent the rewarding effects of a relapse to METH use and thereby improve a patient's probability of remaining in therapy and recovering from their addiction. In this review, we discuss the discovery process of anti-METH mAbs, with a focus on the preclinical development leading to high affinity anti-METH mAb antagonists.

Nicotine vaccines to treat tobacco dependence

Tobacco smoking is globally far more widespread than use of any other substance of abuse. Nicotine is an important tobacco constituent that is responsible for addictive properties of smoking. The currently available medications for the treatment of nicotine addiction have limited efficacy. A challenging novel therapeutic concept is vaccination against nicotine. An efficient vaccine would generate antibodies that sequester nicotine in the blood and prevent its access to the brain. The vaccine would have great potential for treating nicotine addiction and for relapse prevention. We reviewed the current status of vaccines against nicotine addiction that are undergoing clinical trials or are in preclinical development. We discuss problems associated with the development of nicotine vaccines, their efficacy in addiction treatment, challenges and ethical concerns. Existing evidence indicates that nicotine vaccination is well tolerated and capable of inducing an immune response but its effectiveness in increasing smoking abstinence has not been shown so far.

AAVrh.10-mediated expression of an anti-cocaine antibody mediates persistent passive immunization that suppresses cocaine-induced behavior

Cocaine addiction is a major problem affecting all societal and economic classes for which there is no effective therapy. We hypothesized an effective anti-cocaine vaccine could be developed by using an adeno-associated virus (AAV) gene transfer vector as the delivery vehicle to persistently express an anti-cocaine monoclonal antibody in vivo, which would sequester cocaine in the blood, preventing access to cognate receptors in the brain. To accomplish this, we constructed AAVrh.10antiCoc.Mab, an AAVrh.10 gene transfer vector expressing the heavy and light chains of the high affinity anti-cocaine monoclonal antibody GNC92H2. Intravenous administration of AAVrh.10antiCoc.Mab to mice mediated high, persistent serum levels of high-affinity, cocaine-specific antibodies that sequestered intravenously administered cocaine in the blood. With repeated intravenous cocaine challenge, naive mice exhibited hyperactivity, while the AAVrh.10antiCoc.Mab-vaccinated mice were completely resistant to the cocaine. These observations demonstrate a novel strategy for cocaine addiction by requiring only a single administration of an AAV vector mediating persistent, systemic anti-cocaine passive immunity.

Combined cocaine hydrolase gene transfer and anti-cocaine vaccine synergistically block cocaine-induced locomotion

Mice and rats were tested for reduced sensitivity to cocaine-induced hyper-locomotion after pretreatment with anti-cocaine antibody or cocaine hydrolase (CocH) derived from human butyrylcholinesterase (BChE). In Balb/c mice, direct i.p. injection of CocH protein (1 mg/kg) had no effect on spontaneous locomotion, but it suppressed responses to i.p. cocaine up to 80 mg/kg. When CocH was injected i.p. along with a murine cocaine antiserum that also did not affect spontaneous locomotion, there was no response to any cocaine dose. This suppression of locomotor activity required active enzyme, as it was lost after pretreatment with iso-OMPA, a selective BChE inhibitor. Comparable results were obtained in rats that developed high levels of CocH by gene transfer with helper-dependent adenoviral vector, and/or high levels of anti-cocaine antibody by vaccination with norcocaine hapten conjugated to keyhole limpet hemocyanin (KLH). After these treatments, rats were subjected to a locomotor sensitization paradigm involving a “training phase" with an initial i.p. saline injection on day 1 followed by 8 days of repeated cocaine injections (10 mg/kg, i.p.). A 15-day rest period then ensued, followed by a final “challenge" cocaine injection. As in mice, the individual treatment interventions reduced cocaine-stimulated hyperactivity to a modest extent, while combined treatment produced a greater reduction during all phases of testing compared to control rats (with only saline pretreatment). Overall, the present results strongly support the view that anti-cocaine vaccine and cocaine hydrolase vector treatments together provide enhanced protection against the stimulatory actions of cocaine in rodents. A similar combination therapy in human cocaine users might provide a robust therapy to help maintain abstinence.

Predicting the clinical efficacy and potential adverse effects of a humanized anticocaine monoclonal antibody

The effects of a humanized monoclonal antibody (mAb) having high affinity and specificity for cocaine in animal models are reviewed. The mAb reduced the concentration of cocaine in the brain of mice after intravenous injection of cocaine. In addition, the mAb increased the concentration of cocaine required to reinstate cocaine self-administration. These effects may predict clinical efficacy of a passive immunotherapy for reducing the probability of cocaine-induced relapse. However, in the presence of the mAb, once cocaine self-administration was reinstated, the consumption rate of cocaine was increased. This effect is hypothesized to result from a pharmacokinetic/pharmacodynamic interaction. A humanized mAb should minimize adverse events related to the immunogenicity of the mAb protein, and the specificity for cocaine should avoid adverse events related to interactions with physiologically relevant endogenous proteins.

Immune to addiction: the ethical dimensions of vaccines against substance abuse

Promising advances have been made in recent years for a unique class of immunotherapies that use vaccination to combat substance-use disorders. Although such vaccines are potentially useful for addictions, they raise a variety of ethical and social questions.

Cocaine hydrolase encoded in viral vector blocks the reinstatement of cocaine seeking in rats for 6 months

BACKGROUND

Cocaine dependence is a pervasive disorder with high rates of relapse. In a previous study, direct administration of a quadruple mutant albumin-fused butyrylcholinesterase that efficiently catalyzes hydrolysis of cocaine to benzoic acid and ecgonine methyl ester acutely blocked cocaine seeking in an animal model of relapse. In the present experiments, these results were extended to achieve a long-duration blockade of cocaine seeking with a gene transfer paradigm using a related butyrylcholinesterase-based cocaine hydrolase (CocH).

METHODS

Male and female rats were allowed to self-administer cocaine under a fixed-ratio 1 schedule of reinforcement for approximately 14 days. Following the final self-administration session, rats were injected with CocH vector or a control injection (empty vector or saline), and their cocaine solutions were replaced with saline for 14 days to allow for extinction of lever pressing. Subsequently, they were tested for drug-primed reinstatement by administering intraperitoneal injections of saline (S), cocaine (C) (5, 10, and 15 mg/kg), and d-amphetamine according to the following sequence: S, C, S, C, S, C, S, d-amphetamine. Rats then received cocaine-priming injections once weekly for 4 weeks and, subsequently, once monthly for up to 6 months.

RESULTS

Administration of CocH vector produced substantial and sustained CocH activity in plasma that corresponded with diminished cocaine-induced (but not amphetamine-induced) reinstatement responding for up to 6 months following treatment (compared with high-responding control animals).

CONCLUSIONS

These results demonstrate that viral transfer of CocH may be useful in promoting long-term resistance to relapse to cocaine addiction.

Vaccines in the Treatment of Substance Abuse

Reconceptualizing drugs as toxins allowed an important shift in the approach to the treatment of substance abuse, because it ushered in consideration of immunological methods of pharmacotherapy. This paradigm shift represented a dramatic departure from previously considered approaches to pharmacotherapy for substance use disorders (SUDs), which had up until that time focused predominantly on either agonist and/or antagonist medications meant to block drug effects or to decrease reward, reinforcement, or craving. Use of immunological theory in SUD treatment also meant that 1) a potentially addicting medication would not be administered as part of therapy and 2) side effects could be limited, because the individual's immune system would be responsible for delivering treatment.