Polyphosphazene: A New Adjuvant Platform for Cocaine Vaccine Development.

Cocaine is a highly addictive drug that has seen a steady uptrend causing severe health problems worldwide. Currently, there are no approved therapeutics for treating cocaine use disorder; hence, there is an urgent need to identify new medications. Immunopharmacotherapeutics is a promising approach utilizing endogenous antibodies generated through active vaccination, and if properly programmed, can blunt a drug's psychoactive and addictive effects. However, drug vaccine efficacy has largely been limited by the modest levels of antibodies induced. Herein, we explored an adjuvant system consisting of a polyphosphazene macromolecule, specifically poly[di(carboxylatoethylphenoxy)-phosphazene] (PCEP), a biocompatible synthetic polymer that was solicited for improved cocaine conjugate vaccine delivery performance. Our results demonstrated PCEP's superior assembling efficiency with a cocaine hapten as well as with the combined adjuvant CpG oligodeoxynucleotide (ODN). Importantly, this combination led to a higher titer response, balanced immunity, successful sequestering of cocaine in the blood, and a reduction in the drug in the brain. Moreover, a PCEP-cocaine conjugate vaccine was also found to function well via intranasal administration, where its efficacy was demonstrated through the antibody titer, affinity, mucosal IgA production, and a reduction in cocaine's locomotor activity. Overall, a comprehensive evaluation of PCEP integrated within a cocaine vaccine established an advance in the use of synthetic adjuvants in the drugs of abuse vaccine field.

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.

Broadly Neutralizing Synthetic Cannabinoid Vaccines.

Synthetic cannabinoids (SCs) constitute a significant portion of psychoactive substances forming a major public health risk. Due to the wide variety of SCs, broadly neutralizing antibodies generated by active immunization present an intriguing pathway to combat cannabinoid use disorder. Here, we probed hapten design for antibody affinity and cross reactivity against two classes of SCs. Of the 10 haptens screened, 3 vaccine groups revealed submicromolar IC50, each targeting 5-6 compounds in our panel of 22 drugs. Moreover, SCs were successfully sequestered when administered by vaping or intraperitoneal injection, which was confirmed within animal models by observing locomotion, body temperature, and pharmacokinetics. We also discovered synergistic effects to simultaneously blunt two drug classes through an admixture vaccine approach. Collectively, our study provides a comprehensive foundation for the development of vaccines against SCs.

Pharmacokinetic Approach to Combat the Synthetic Cannabinoid PB-22.

Synthetic cannabinoids are part of a group of drugs called new psychoactive substances. Most of these cannabinoids are unregulated, and there are no therapeutic treatments for their addictive properties or reversing a potential overdose. Vaccination and catalytic antibodies strategies were investigated to assess their ability to blunt the psychoactive properties of the cannabinoid PB-22. To complement these antibody concentric investigations, we also disclose the discovery of the enzymatic degradation of this cannabinoid. Serum factors including albumin and carboxylesterase were found to catalyze the hydrolysis of PB-22. Affinity, kinetics, animal behavior, and biodistribution studies were utilized to evaluate the efficiency of these pharmacokinetic approaches. Our findings suggest simple antibody binding as the most efficacious means for altering PB-22's effect on the brain. Catalytic approaches only translated to esterases being capable of PB-22's degradation with a catalytic antibody approach providing no proclivity for PB-22's hydrolysis. Pharmacokinetic approaches provide a powerful strategy for treating substance abuse disorders and overdose for drugs where no therapeutic is available.

Improvements on a chemically contiguous hapten for a vaccine to address fentanyl-contaminated heroin.

Unintentional overdose deaths related to opioids and psychostimulants have increased in prevalence due to the adulteration of these drugs with fentanyl. Synergistic effects between illicit compounds and fentanyl cause aggravated respiratory depression, leading to inadvertent fatalities. Traditional small-molecule therapies implemented in the expanding opioid epidemic present numerous problems since they interact with the same opioid receptors in the brain as the abused drugs. In this study, we report an optimized dual hapten for use as an immunopharmacotherapeutic tool in order to develop antibodies capable of binding to fentanyl-contaminated heroin in the periphery, thus impeding the drugs' psychoactive effects on the central nervous system. This vaccine produced antibodies with nanomolar affinities and effectively blocked opioid analgesic effects elicited by adulterated heroin. These findings provide further insight into the development of chemically contiguous haptens for broad-spectrum immunopharmacotherapies against opioid use disorders.

A Highly Efficacious Carfentanil Vaccine That Blunts Opioid-Induced Antinociception and Respiratory Depression.

The opioid epidemic remains a dire public health crisis with millions of people currently suffering from opioid use disorder (OUD) and tens of thousands dying each year. Synthetic opioids are most responsible for the crisis because of their extreme potency and ease of manufacture. Carfentanil for example has an estimated potency 10,000 times greater than morphine and thus is highly dangerous for human use. Herein, we report two synthetic opioid vaccines that elicited high-affinity antibodies against carfentanil and fentanyl with cross-reactivity to other synthetic opioids in mice and offered protection against opioid-induced respiratory depression, the primary cause of overdose deaths. These vaccines also successfully diminished drug biodistribution to the brain and shielded against opioid analgesic effects. Collectively, these findings provide new insights into the development of immunotherapeutic strategies aimed at opioid abuse and overdose.

Sulfonate-isosteric replacement examined within heroin-hapten vaccine design.

Heroin overdose and addiction remain significant health and economic burdens in the world today costing billions of dollars annually. Moreover, only limited pharmacotherapeutic options are available for treatment of heroin addiction. In our efforts to combat the public health threat posed by heroin addiction, we have developed vaccines against heroin. To expand upon our existing heroin-vaccine arsenal, we synthesized new aryl and alkyl sulfonate ester haptens; namely aryl-mono-sulfonate (HMsAc) and Aryl/alkyl-di-sulfonate (H(Ds)2) as carboxyl-isosteres of heroin then compared them to our model heroin-hapten (HAc) through vaccination studies. Heroin haptens were conjugated to the carrier protein CRM197 and the resulting CRM-immunoconjugates were used to vaccinate Swiss Webster mice following an established immunization protocol. Binding studies revealed that the highest affinity anti-heroin antibodies were generated by the HMsAc vaccine followed by the HAc and H(Ds)2 vaccines, respectively (HMsAc > HAc≫HDs2). However, neither the HMsAc nor H(Ds)2 vaccines were able to generate high affinity antibodies to the psychoactive metabolite 6-acetyl morphine (6-AM), in comparison to the HAc vaccine. Blood brain bio-distribution studies supported these binding results with vaccine efficiency following the trend HAc > HMsAc â‰« H(Ds)2 The work described herein provides insight into the use of hapten-isosteric replacement in vaccine drug design.

Enhancement of a Heroin Vaccine through Hapten Deuteration.

The United States is in the midst of an unprecedented epidemic of opioid substance use disorder, and while pharmacotherapies including opioid agonists and antagonists have shown success, they can be inadequate and frequently result in high recidivism. With these challenges facing opioid use disorder treatments immunopharmacotherapy is being explored as an alternative therapy option and is based upon antibody-opioid sequestering to block brain entry. Development of a heroin vaccine has become a major research focal point; however, producing an efficient vaccine against heroin has been particularly challenging because of the need to generate not only a potent immune response but one against heroin and its multiple psychoactive molecules. In this study, we explored the consequence of regioselective deuteration of a heroin hapten and its impact upon the immune response against heroin and its psychoactive metabolites. Deuterium (HdAc) and cognate protium heroin (HAc) haptens were compared head to head in an inclusive vaccine study. Strikingly the HdAc vaccine granted greater efficacy in blunting heroin analgesia in murine behavioral models compared to the HAc vaccine. Binding studies confirmed that the HdAc vaccine elicited both greater quantities and equivalent or higher affinity antibodies toward heroin and 6-AM. Blood-brain biodistribution experiments corroborated these affinity tests. These findings suggest that regioselective hapten deuteration could be useful for the resurrection of previous drug of abuse vaccines that have met limited success in the past.

A fentanyl vaccine constructed upon opsonizing antibodies specific for the Galα1-3Gal epitope.

A double conjugation strategy was implemented to produce an anti-fentanyl vaccine, which was predicated upon preformed-antibody-assisted antigen presentation. The new vaccine was found to reduce the psychoactive effects of fentanyl without the addition of the immunostimulant CpG oligodeoxynucleotide.

Monoclonal Antibodies for Combating Synthetic Opioid Intoxication.

Opioid abuse in the United States has been declared a national crisis and is exacerbated by an inexpensive, readily available, and illicit supply of synthetic opioids. Specifically, fentanyl and related analogues such as carfentanil pose a significant danger to opioid users due to their high potency and rapid acting depression of respiration. In recent years these synthetic opioids have become the number one cause of drug-related deaths. In our research efforts to combat the public health threat posed by synthetic opioids, we have developed monoclonal antibodies (mAbs) against the fentanyl class of drugs. The mAbs were generated in hybridomas derived from mice vaccinated with a fentanyl conjugate vaccine. Guided by a surface plasmon resonance (SPR) binding assay, we selected six hybridomas that produced mAbs with 10-11 M binding affinity for fentanyl, yet broad cross-reactivity with related fentanyl analogues. In mouse antinociception models, our lead mAb (6A4) could blunt the effects of both fentanyl and carfentanil in a dose-responsive manner. Additionally, mice pretreated with 6A4 displayed enhanced survival when subjected to fentanyl above LD50 doses. Pharmacokinetic analysis revealed that the antibody sequesters large amounts of these drugs in the blood, thus reducing drug biodistribution to the brain and other tissue. Lastly, the 6A4 mAb could effectively reverse fentanyl/carfentanil-induced antinociception comparable to the opioid antagonist naloxone, the standard of care drug for treating opioid overdose. While naloxone is known for its short half-life, we found the half-life of 6A4 to be approximately 6 days in mice, thus monoclonal antibodies could theoretically be useful in preventing renarcotization events in which opioid intoxication recurs following quick metabolism of naloxone. Our results as a whole demonstrate that monoclonal antibodies could be a desirable treatment modality for synthetic opioid overdose and possibly opioid use disorder.