Cocaine binding to the Fab fragment of a humanized anti-cocaine mAb quantitated by dye absorption and fluorescence spectroscopy.

In this work, we establish that cocaine binding to the Fab fragment of a recombinant humanized anti-cocaine mAb (h2E2) can be directly and easily quantitated using simple and inexpensive absorption and fluorescence measurements, employing dyes typically used for differential scanning fluorimetry, DASPMI and SYPRO Orange. For concentrated samples of the Fab fragment, absorbance spectroscopy employing these dyes reveals the number of cocaine sites present, using either DASPMI (by measuring the increase in dye absorbance) or SYPRO Orange (by measuring the change in dye maximal absorbance wavelength). Interestingly, we observed that cocaine binding to the Fab fragment had a much different effect on the SYPRO Orange dye absorbance than previously reported for the intact h2E2 mAb, resulting in a large decrease in the total dye absorbance for the Fab fragment, in contrast to previous results with the intact h2E2 mAb. For dilute samples of Fab fragment, a dye fluorescence emission spectroscopy assay was developed to quantitate the number of cocaine (and other high affinity cocaine metabolites) binding sites via the ligand-induced decrease in fluorescence emission of both of these extrinsic dyes. The difference in the cocaine titrations for the high affinity (Kd < 30 nM) ligands, cocaine, cocaethylene and benzoylecgonine and the low affinity (Kd > 30 µM) ligands, norcocaine, ecgonine methyl ester, and ecgonine were obvious using this assay. These simple, direct, and inexpensive techniques should prove useful for evaluation of other small molecule antigen binding Fab fragments, enabling quantitation and rapid biochemical assessments necessary for determining Fab fragment suitability for in vivo uses and other assays and experiments.

Can cocaine-induced neuroinflammation explain maladaptive cocaine-associated memories?

Persistent and intrusive memories define a number of psychiatric disorders, including posttraumatic stress disorder and substance use disorder. In the latter, memory for drug-paired cues plays a critical role in sustaining compulsive drug use as these are potent triggers of relapse. As with many drugs, cocaine-cue associated memory is strengthened across presentations as cues become reliable predictors of drug availability. Recently, the targeting of cocaine-associated memory through disruption of the reconsolidation process has emerged as a potential therapeutic strategy; reconsolidation reflects the active process by which memory is re-stabilized after retrieval. In addition, a separate line of work reveals that neuroinflammatory markers, regulated by cocaine intake, play a role in memory processes. Our review brings these two literatures together by summarizing recent findings on cocaine-associated reconsolidation and cocaine-induced neuroinflammation. We discuss the interactions between reconsolidation processes and neuroinflammation following cocaine use, concluding with a new perspective on treatment to decrease risk of relapse to cocaine use.

Immunotherapy for treating methamphetamine, heroin and cocaine use disorders.

Drug addiction is a serious health problem prevalent worldwide. Currently available therapies including pharmacotherapy and psychotherapy are insufficient to meet the clinical needs for treating drug abuse. Recently, immunotherapy has emerged as a promising approach to treat such drug-use disorders. Pharmacokinetic antagonists are used in immunotherapy, functioning by sequestering the drugs in the periphery but without allowing the drug to cross the blood-brain barrier. This can reduce the toxic and rewarding effects of the drugs, while preventing addiction and facilitating reduced relapse rates. Herein, we update recent developments in the immunotherapeutic strategies to treat abuse of drugs like methamphetamine, heroin and cocaine. In addition, we summarize the drug design used so far and its optimization strategies. Further, we document the efficacy of anti-drug vaccines and monoclonal antibodies, with an aim to promote development of new anti-drug immunotherapies.

Demographic, Clinical, and Immunologic Correlates among a Cohort of 50 Cocaine Users Demonstrating Antineutrophil Cytoplasmic Antibodies.

OBJECTIVE: Cocaine/levamisole-associated autoimmunity syndrome (CLAAS) is a poorly understood form of drug-induced autoimmunity. Our goals were to better characterize the spectrum of clinical and immunologic features of CLAAS, to identify demographic risk factors, and to generate new hypotheses regarding pathogenesis. METHODS: CLAAS subjects were identified between 2001 and 2015 at the University of Washington Medical Center, Harborview Medical Center, and affiliated clinics in Seattle, Washington, USA. Demographic, clinical, and immunologic variables were collected and correlated using contingency and logistic regression analyses. We used similar analyses to compare CLAAS subjects with all individuals exhibiting antineutrophil cytoplasmic antibodies (ANCA+) or cocaine use (Cocaine+) in an associated deidentified clinical data repository. RESULTS: We identified 50 CLAAS subjects. Compared to all Cocaine+ individuals (n = 2740), CLAAS subjects were more likely to be female and less likely to self-identify as black/African American. CLAAS subjects showed several ANCA patterns, including anti-MPO (myeloperoxidase)/anti-PR3 (proteinase 3) dual reactivity, a finding that appears to be specific to CLAAS. Hematologic, renal, and skin abnormalities were most frequently reported, including neutropenia and skin purpura. Finally, we observed strong, independent associations between the cytoplasmic ANCA (C-ANCA) pattern and mortality. CONCLUSION: We identify sex and race as important risk modifiers in the developing CLAAS among cocaine users. The development of C-ANCA was associated with increased mortality. Moreover, we confirm the enriched presence of anti-MPO/anti-PR3 dual reactivity in CLAAS, further supporting the diagnostic utility of this feature.

Cocaine-induced release of CXCL10 from pericytes regulates monocyte transmigration into the CNS.

Cocaine is known to facilitate the transmigration of inflammatory leukocytes into the brain, an important mechanism underlying neuroinflammation. Pericytes are well-recognized as important constituents of the blood-brain barrier (BBB), playing a key role in maintaining barrier integrity. In the present study, we demonstrate for the first time that exposure of human brain vascular pericytes to cocaine results in enhanced secretion of CXCL10, leading, in turn, to increased monocyte transmigration across the BBB both in vitro and in vivo. This process involved translocation of σ-1 receptor (σ-1R) and interaction of σ-1R with c-Src kinase, leading to activation of the Src-PDGFR-ß-NF-κB pathway. These findings imply a novel role for pericytes as a source of CXCL10 in the pericyte-monocyte cross talk in cocaine-mediated neuroinflammation, underpinning their role as active components of the innate immune responses.

Indomethacin blocks the increased conditioned rewarding effects of cocaine induced by repeated social defeat.

It is well established that repeated social defeat stress can induce negative long-term consequences such as increased anxiety-like behavior and enhances the reinforcing effect of psychostimulants in rodents. In the current study, we evaluated how the immune system may play a role in these long-term effects of stress. A total of 148 OF1 mice were divided into different experimental groups according to stress condition (exploration or social defeat) and pre-treatment (saline, 5 or 10 mg/kg of the anti-inflammatory indomethacin) before each social defeat or exploration episode. Three weeks after the last social defeat, anxiety was evaluated using an elevated plus maze paradigm. After this test, conditioned place preference (CPP) was induced by a subthreshold dose of cocaine (1 mg/kg). Biological samples were taken four hours after the first and the fourth social defeat, 3 weeks after the last defeat episode, and after the CPP procedure. Plasma and brain tissue (prefrontal cortex, striatum and hippocampus) were used to determine the levels of the pro-inflammatory cytokine interleukin 6 (IL-6). Results showed an increase of peripheral and brain IL-6 levels after the first and fourth social defeat that was reverted three weeks later. Intraperitoneal administration of the anti-inflammatory drug indomethacin before each episode of stress prevented this enhancement of IL-6 levels and also reversed the increase in the rewarding effects of cocaine in defeated mice. Conversely, this protective effect was not observed with respect to the anxiogenic consequences of social stress. Our results confirm the hypothesis of a modulatory proinflammatory contribution to stress-induced vulnerability to drug abuse disorders and highlight anti-inflammatory interventions as a potential therapeutic tool to treat stress-related addiction disorders.

From Traumatic Childhood to Cocaine Abuse: The Critical Function of the Immune System.

BACKGROUND: Experiencing traumatic childhood is a risk factor for developing substance use disorder, but the mechanisms that underlie this relationship have not been determined. Adverse childhood experiences affect the immune system, and the immune system mediates the effects of psychostimulants. However, whether this system is involved in the etiology of substance use disorder in individuals who have experienced early life stress is unknown. METHODS: In this study, we performed a series of ex vivo and in vivo experiments in mice and humans to define the function of the immune system in the early life stress-induced susceptibility to the neurobehavioral effects of cocaine. RESULTS: We provide evidence that exposure to social stress at an early age permanently sensitizes the peripheral (splenocytes) and brain (microglia) immune responses to cocaine in mice. In the brain, microglial activation in the ventral tegmental area of social-stress mice was associated with functional alterations in dopaminergic neurotransmission, as measured by whole-cell voltage clamp recordings in dopamine neurons. Notably, preventing immune activation during the social-stress exposure reverted the effects of dopamine in the ventral tegmental area and the cocaine-induced behavioral phenotype to control levels. In humans, cocaine modulated toll-like receptor 4-mediated innate immunity, an effect that was enhanced in those addicted to cocaine who had experienced a difficult childhood. CONCLUSIONS: Collectively, our findings demonstrate that sensitization to cocaine in early life-stressed individuals involves brain and peripheral immune responses and that this mechanism is shared between mice and humans.

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.

A novel Python program for implementation of quality control in the ELISA.

The use of semi-quantitative assays such as the enzyme-linked immunosorbent assay (ELISA) requires stringent quality control of the data. However, such quality control is often lacking in academic settings due to unavailability of software and knowledge. Therefore, our aim was to develop methods to easily implement Levey-Jennings quality control methods. For this purpose, we created a program written in Python (a programming language with an open-source license) and tested it using a training set of ELISA standard curves quantifying the Fab fragment of an anti-cocaine monoclonal antibody in mouse blood. A colorimetric ELISA was developed using a goat anti-human anti-Fab capture method. Mouse blood samples spiked with the Fab fragment were tested against a standard curve of known concentrations of Fab fragment in buffer over a period of 133days stored at 4°C to assess stability of the Fab fragment and to generate a test dataset to assess the program. All standard curves were analyzed using our program to batch process the data and to generate Levey-Jennings control charts and statistics regarding the datasets. The program was able to identify values outside of two standard deviations, and this identification of outliers was consistent with the results of a two-way ANOVA. This program is freely available, which will help laboratories implement quality control methods, thus improving reproducibility within and between labs. We report here successful testing of the program with our training set and development of a method for quantification of the Fab fragment in mouse blood.

Cocaine dependence does not contribute substantially to white matter abnormalities in HIV infection.

This study investigated the association of HIV infection and cocaine dependence with cerebral white matter integrity using diffusion tensor imaging (DTI). One hundred thirty-five participants stratified by HIV and cocaine status (26 HIV+/COC+, 37 HIV+/COC-, 37 HIV-/COC+, and 35 HIV-/COC-) completed a comprehensive substance abuse assessment, neuropsychological testing, and MRI with DTI. Among HIV+ participants, all were receiving HIV care and 46% had an AIDS diagnosis. All COC+ participants were current users and met criteria for cocaine use disorder. We used tract-based spatial statistics (TBSS) to assess the relation of HIV and cocaine to fractional anisotropy (FA) and mean diffusivity (MD). In whole-brain analyses, HIV+ participants had significantly reduced FA and increased MD compared to HIV- participants. The relation of HIV and FA was widespread throughout the brain, whereas the HIV-related MD effects were restricted to the corpus callosum and thalamus. There were no significant cocaine or HIV-by-cocaine effects. These DTI metrics correlated significantly with duration of HIV disease, nadir CD4+ cell count, and AIDS diagnosis, as well as some measures of neuropsychological functioning. These results suggest that HIV is related to white matter integrity throughout the brain, and that HIV-related effects are more pronounced with increasing duration of infection and greater immune compromise. We found no evidence for independent effects of cocaine dependence on white matter integrity, and cocaine dependence did not appear to exacerbate the effects of HIV.

Neutrophil extracellular traps as a potential source of autoantigen in cocaine-associated autoimmunity.

Objective: Exposure to illicit cocaine and its frequent adulterant, levamisole, is associated with ANCAs targeting neutrophil elastase (NE), neutropenia and vasculitic/thrombotic skin purpura. The mechanisms of cocaine/levamisole-associated autoimmunity (CLAA) are unknown. The aim of this study was to assess the ability of cocaine and levamisole to induce the release of neutrophil extracellular traps (NETs), a potential source of autoantigen and tissue injury. Methods: We performed quantitative and qualitative assessment of NET formation in neutrophils from healthy donors exposed to either drug in vitro . In addition, IgG from sera of individuals with CLAA (CLAA-IgG) was assessed for its ability to enhance formation of, and to bind to, drug-induced NETs. Results: Both cocaine and levamisole could induce formation of NETs enriched in NE and, potentially, inflammatory mitochondrial DNA. Both drugs could also augment simultaneous release of B cell-activating factor belonging to the TNF family (BAFF). CLAA-IgG, but not IgG from healthy individuals, could potentiate drug-induced NETosis. Furthermore, CLAA-IgG, but not ANCA + control IgG, bound to drug-induced NETs in a pattern consistent with NE targeting. Conclusion: Both cocaine and levamisole may contribute to the development of ANCAs by inducing release of potentially inflammatory NETs in association with NE autoantigen and BAFF. Enhancement of drug-induced NET release by CLAA-IgG provides a potential mechanism linking vasculitis/pupuric skin disease to acute drug exposure in patients with CLAA. Further study of this under-recognized form of autoimmunity will be likely to provide mechanistic insight into ANCA-associated vasculitis and other diseases associated with NETosis.

The effects of a repeated dose of a recombinant humanized anti-cocaine monoclonal antibody on cocaine self-administration in rats.

BACKGROUND: Immunotherapy has shown potential as a treatment for cocaine abuse. The humanized recombinant anti-cocaine monoclonal antibody (mAb) with the preclinical designation h2E2 has been shown to decrease cocaine concentrations in the brain in rats, but its effects on cocaine self-administration behavior have never been tested. METHODS: The amount of cocaine needed to reinstate self-administration behavior (priming threshold) was calculated and the inter-injection intervals at unit doses of 0.3µmol/kg and 3µmol/kg during maintained self-administration were measured over a five-week baseline period. Rats trained to self-administer cocaine were infused with two doses of h2E2 (120mg/kg i.v.) 35days apart. Priming threshold and inter-injection intervals were measured for 35days after both injections. RESULTS: After both injections of h2E2, priming thresholds were significantly increased (3-fold) compared to expected baseline and then gradually declined over 35days. A significant decrease (15-33%) in inter-injection intervals during maintained self-administration was also observed following both h2E2 infusions at the lower dose, and after the first injection at the higher dose. No significant decreases in body weight were observed after either injection, indicating a lack of toxicity following a second injection. CONCLUSIONS: These data predict that the safety and effectiveness of h2E2 will be maintained after multiple treatments of this potential immunotherapy for cocaine abuse.

The future potential for cocaine vaccines.

INTRODUCTION: Addiction to cocaine is a major problem around the world, but especially in developed countries where the combination of wealth and user demand has created terrible social problems. Although only some users become truly addicted, those who are often succumb to a downward spiral in their lives from which it is very difficult to escape. From the medical perspective, the lack of effective and safe, non-addictive therapeutics has instigated efforts to develop alternative approaches for treatment, including anticocaine vaccines designed to block cocaine's pharmacodynamic effects. AREAS COVERED: This paper discusses the implications of cocaine pharmacokinetics for robust vaccine antibody responses, the results of human vaccine clinical trials, new developments in animal models for vaccine evaluation, alternative vaccine formulations and complementary therapy to enhance anticocaine effectiveness. EXPERT OPINION: Robust anti-cocaine antibody responses are required for benefit to cocaine abusers, but since any reasonably achievable antibody level can be overcome with higher drug doses, sufficient motivation to discontinue use is also essential so that the relative barrier to cocaine effects will be appropriate for each individual. Combining a vaccine with achievable levels of an enzyme to hydrolyze cocaine to inactive metabolites, however, may substantially increase the blockade and improve treatment outcomes.

Vaccine for cocaine dependence: a randomized double-blind placebo-controlled efficacy trial.

AIMS: We evaluated the immunogenicity, efficacy, and safety of succinylnorcocaine conjugated to cholera toxin B protein as a vaccine for cocaine dependence. METHODS: This 6-site, 24 week Phase III randomized double-blind placebo-controlled trial assessed efficacy during weeks 8 to 16. We measured urine cocaine metabolites thrice weekly as the main outcome. RESULTS: The 300 subjects (76% male, 72% African-American, mean age 46 years) had smoked cocaine on average for 13 days monthly at baseline. We hypothesized that retention might be better and positive urines lower for subjects with anti-cocaine IgG levels of ≥42 µg/mL (high IgG), which was attained by 67% of the 130 vaccine subjects receiving five vaccinations. Almost 3-times fewer high than low IgG subjects dropped out (7% vs 20%). Although for the full 16 weeks cocaine positive urine rates showed no significant difference between the three groups (placebo, high, low IgG), after week 8, more vaccinated than placebo subjects attained abstinence for at least two weeks of the trial (24% vs 18%), and the high IgG group had the most cocaine-free urines for the last 2 weeks of treatment (OR=3.02), but neither were significant. Injection site reactions of induration and tenderness differed between placebo and active vaccine, and the 29 serious adverse events did not lead to treatment related withdrawals, or deaths. CONCLUSIONS: The vaccine was safe, but it only partially replicated the efficacy found in the previous study based on retention and attaining abstinence.

Cocaine alters cytokine profiles in HIV-1-infected African American individuals in the DrexelMed HIV/AIDS genetic analysis cohort.

BACKGROUND: This study evaluated the relationship between illicit drug use and HIV-1 disease severity in HIV-1-infected patients enrolled in the DREXELMED HIV/AIDS Genetic Analysis Cohort. Because cocaine is known to have immunomodulatory effects, the cytokine profiles of preferential nonusers, cocaine users, and multidrug users were analyzed to understand the effects of cocaine on cytokine modulation and HIV-1 disease severity. METHODS: Patients within the cohort were assessed approximately every 6 months for HIV-1 clinical markers and for history of illicit drug, alcohol, and tobacco use. The Luminex human cytokine 30-plex panel was used for cytokine quantitation. Analysis was performed using a newly developed biostatistical model. RESULTS: Substance abuse was common within the cohort. Using the drug screens at the time of each visit, the subjects in the cohort were categorized as preferential nonusers, cocaine users, or multidrug users. The overall health of the nonuser population was better than that of the cocaine users, with peak and current viral loads in nonusers substantially lower than those in cocaine and multidrug users. Among the 30 cytokines investigated, differential levels were established within the 3 populations. The T-helper 2 cytokines, interleukin-4 and -10, known to play a critical role during HIV-1 infection, were positively associated with increasing cocaine use. Clinical parameters such as latest viral load, CD4 T-cell counts, and CD4:CD8 ratio were also significantly associated with cocaine use, depending on the statistical model used. CONCLUSIONS: Based on these assessments, cocaine use seems to be associated with more severe HIV-1 disease.

Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients.

Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 µmol/L concentrations) did not induce apoptosis, but 200 to 1000 µmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers.

Aberrant disgust responses and immune reactivity in cocaine-dependent men.

BACKGROUND: Infectious diseases are the most common and cost-intensive health complications associated with drug addiction. There is wide belief that drug-dependent individuals expose themselves more regularly to disease-related pathogens through risky behaviors such as sharing pipes and needles, thereby increasing their risk for contracting an infectious disease. However, evidence is emerging indicating that not only lifestyle but also the immunomodulatory effects of addictive drugs, such as cocaine, may account for their high infection risk. As feelings of disgust are thought to be an important psychological mechanism in avoiding the exposure to pathogens, we sought to investigate behavioral, physiological, and immune responses to disgust-evoking cues in both cocaine-dependent and healthy men. METHODS: All participants (N = 61) were exposed to neutral and disgust-evoking photographs depicting food and nonfood images while response accuracy, latency, and skin conductivity were recorded. Saliva samples were collected before and after exposure to neutral and disgusting images, respectively. Attitudes toward disgust and hygiene behaviors were assessed using questionnaire measures. RESULTS: Response times to disgust-evoking photographs were prolonged in all participants, and specifically in cocaine-dependent individuals. While viewing the disgusting images, cocaine-dependent individuals exhibited aberrant skin conductivity and increased the secretion of the salivary cytokine interleukin-6 relative to control participants. CONCLUSION: Our data provide evidence of a hypersensitivity to disgusting stimuli in cocaine-dependent individuals, possibly reflecting conditioned responses to noningestive sources of infection. Coupled with a lack of interoception of bodily signals, aberrant disgust responses might lead to increased infection susceptibility in affected individuals.

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.

DBH gene as predictor of response in a cocaine vaccine clinical trial.

We examined a pharmacogenetic association of the dopamine ß-hydroxylase (DBH) gene with a response to an anti-cocaine vaccine that was tested in a recent clinical trial. This gene is associated with cocaine-induced paranoia, which has a slower onset than the euphoria from cocaine. The vaccine reduced euphoria by slowing the entry of cocaine into the brain, but it may not reduce aversive symptoms like paranoia. A 16-week Phase IIb randomized double-blind placebo-controlled trial of 114 cocaine and opioid dependent subjects who received five vaccinations over the first 12 weeks was examined. We genotyped 71 subjects for the rs1611115 (-1021C>T) variant of the DBH gene and compared vaccine to placebo subjects on cocaine-free urines. Using repeated measures analysis of variance, corrected for population structure, vaccine pharmacotherapy reduced cocaine positive urines significantly based on DBH genotype. Patients with the low DßH level genotype dropped from 77% to 51% on vaccine (p=0.0001), while those with the normal DßH level genotype dropped from 83% to 72%. Placebo showed no effect on cocaine use overall or by genotype. This study indicates that a patient's DBH genotype could be used to identify a subset of individuals for whom vaccine treatment may be an effective pharmacotherapy for cocaine dependence.