Funded Projects

Addiction to opioids is related to the physiology of the brain’s dopamine-based reward system. As a modulator of dopaminergic systems, the neurotensin 1 receptor (NTR1) should be a molecular target for treating addictive disorders; however, few non-peptide brain penetrant neurotensin modulators have been identified, and orthosteric NTR1 ligands display side effects that have limited their clinical development. This group discovered a series of brain-penetrant NTR1 modulators, including a lead compound SBI-553, with a unique mechanism of action at NTR1. SBI-553 is an orally available, brain penetrant ?-arrestin biased allosteric modulator of NTR1, which shows efficacy in a range of addiction models and circumvents the clinically limiting side effects. While potentially high risk, the activity of SBI-553 has been validated in vitro and in vivo, and the initial safety profiling indicates no issues that would preclude further development. This study will develop SBI-553 as a treatment for opioid use disorder.

Deaths from opioid overdose continue to rise; from 2015 to 2016, there was a 28 percent increase in the number of fatal overdoses. Currently available pharmacotherapies include MOR agonists (e.g., buprenorphine) and antagonists (e.g., naloxone), all of which suffer from specific and clear limitations. To address the main deficits in these treatments, the researchers will develop and optimize medications with longer duration of action that prevent and reverse the effects of opioids in a manner that is not surmounted by increasing doses of agonist. Their pilot studies in monkeys show that the pseudo irreversible MOR selective antagonist methocinnamox (MCAM) decreases heroin but not cocaine self-administration, decreases choice for remifentanil in a food/drug choice procedure, and reverses—as well as protects against—respiratory depression by heroin, with a single injection being effective for a week or longer. Bringing a medication like this to marketable fruition could significantly improve the treatment of OUD and save lives by providing insurmountable extended protection after rescue from overdose, including from ultra-potent fentanyl analogs.

The United States has seen dramatic increases in fatal overdoses due to heroin, counterfeit prescription drugs, and cocaine adulterated with fentanyl or fentanyl-like analogs. Current medications may not be sufficient to address the opioid overdose epidemic. As a complementary strategy, the researchers plan to develop vaccines against fentanyl and fentanyl-like compounds to reduce their abuse liability and the growing incidence of fatal overdoses. This research team has already developed vaccines against heroin and oxycodone that stimulate the production of antibodies effective in reducing opioid distribution to the brain, opioid-induced behaviors, and opioid-induced respiratory depression and have identified a promising fentanyl vaccine candidate cued up for optimization. Successful completion of an anti-fentanyl vaccine development project could offer a long-lasting, safe, and cost-effective intervention complementary to medication-assisted treatment (MAT) and may reduce overdoses in opioid users as well as protect people in professions (e.g., law enforcement, airport security, postal workers) at risk of accidental exposure to fentanyl and fentanyl analogs.

Chronic pain affects an estimated 100 million Americans, or one third of the U.S. population, and it is the primary reason Americans are on disability. Although many treatments are available for pain, the most potent class of analgesics relies on opioid analogs, whose limitations and well-known adverse effects have contributed to the present opioid crisis. New pharmacotherapies for pain management are sorely needed. MTX1604, a synthetic endomorphin analog, has emerged as a highly effective analgesic that exhibits reduced reward potential and respiratory suppression, and a robust duration of efficacy in a variety of validated animal models of acute, neuropathic, inflammatory, post-operative, and visceral pain. This project will generate additional preclinical characterization data of MTX1604 and advance clinical development toward FDA approval. If successful, this medication development project could offer patients a novel non-addictive, potent, and safe analgesic and thus have a direct impact on the opioid crisis.

Neurostimulation techniques, such as transcranial direct current stimulation (tDCS), have been used as interventions for substance use disorders. This is a supplement to the currently NIDA-funded UG3 DA047793, “tDCS to Decrease Opioid Relapse,” which will measure behavioral and brain responses following tDCS stimulation delivered during tasks that use a particular brain network involved in cognitive control, and utilizing FMRI to assess the effects. This supplement allows the researchers to add an EEG measurement to the study, to get a complete picture of how tDCS might affect the function of key brain networks in ways that could be helpful for SUDs.

Opioid use disorder (OUD) is a significant public health problem in the United States. Particularly troubling is the rapid evolution of an opioid epidemic within the past decade, characterized by a surge in unintentional overdose deaths involving synthetic opioids, such as fentanyl. The current standard of care for opioid overdose is reversal with opioid antagonist naloxone. Naloxone is effective at reversing overdose from prescription opioids and heroin, but less effective when combating fentanyl, due to fentanyl?s high potency. Therapeutic monoclonal antibodies (mAbs) against fentanyl could overcome this problem by specifically preventing the drug from entering the central nervous system, averting overdose and attenuating opioid-induced respiratory depression. This study will develop and design of laboratory protocols needed to establish a Good Manufacturing Practice (GMP) process, quality assurance protocol, and stability profile for a new human mAb against fentanyl. Subsequent production of current GMP material will enable Good Laboratory Practice (GLP) toxicology studies in rats and dogs and eventually a Phase I/IIa clinical trial. This material will also be used in final opioid-induced respiratory depression studies in mice and non-human primates to confirm therapeutic efficacy of final drug product. If successful, these activities will enable filing for an investigational new drug application for this mAb candidate with the FDA.

The excruciating multiday experience of opioid withdrawal syndrome (OWS), is exacerbated by the opioid antagonist drugs naloxone and naltrexone. This industry-academia collaboration will explore the potential of the glutamate AMPA receptor antagonist Tezampanel (TZP). Animal studies have shown reduced hyperactivity in brain circuits involved in OWS, without relying on direct stimulation or antagonism of the opioid system ,and has already been delivered to over 500 human subjects and found to be safe for a potential migraine indication. This proposal will build up the evidence needed to apply for and conduct open label and blinded placebo-controlled human trials of TZP safety and efficacy for OWS. If successful, this project will allow planning for a pivotal registration trial for TZP for OWS, and as a transitional treatment to long-term recovery on naltrexone and help us stem the tide of the opioid crisis.

Over 2 million Americans have an Opioid Use Disorder (OUD) and the risks associated with misuse of opioids have prompted a public health crisis. There are three effective FDA-approved drugs for medication assisted treatment (MAT) of OUD. However, while MAT can reduce overall OUD related mortality by as much as fifty percent, relapse and treatment discontinuation are common within the first 5 to 12 weeks of MAT. As longer treatment retention is correlated with better long-term outcomes, the development of an adjunctive medication to alleviate key psychiatric symptoms associated with treatment failure would address an important unmet need. This study seeks to evaluate the safety and efficacy of brexpiprazole as adjunctive treatment to buprenorphine/naloxone in OUD. If successful, this study could enhance the effectiveness of OUD treatments by extending the duration of treatment, thereby reducing the likelihood for relapse and overdose.

Opioids account for nearly 70 percent of overdose deaths in the United States, with fentanyl and heroin use the most common causes. The goal of this project is to create a vaccine to elicit serum antibodies that bind and sequester the drug in the blood, preventing it from crossing the blood-brain barrier where it acts on the central nervous system. Current opioid vaccine strategies require multiple boosts and months to reach peak titers, the level of antibodies in a blood sample, and have yet to show protection against lethal overdose. In this project, researchers will use a bacteriophage virus-like particle vaccine platform to engineer and test the effectiveness of a combined vaccine to elicit high titer antibodies quickly to protect against lethal overdose from fentanyl or heroin.

Kappa opioid receptors (KOR) are expressed in brain areas that control reward, motivation, and anxiety. Upon opioid drug withdrawal and abstinence, dysregulated KOR signaling can result in aversive physical and affective states that are a major driver of relapse. Preclinical data have demonstrated that antagonism of KOR can reduce the physical symptoms of opioid withdrawal. Currently, the alpha 2-adrenergic agonist lofexidine is the only approved therapy for the mitigation of the physical symptoms of opioid withdrawal but it is only modestly effective and can have significant unwanted side effects. Cerevel Therapeutics has identified a novel selective KOR antagonist, CVL-354, with unique properties and good preclinical safety margins. This project will assess this drug in early human safety/pharmacokinetics and occupancy studies. Future studies will then be able to assess efficacy of this drug in acute opioid withdrawal.