Funded Projects

This project proposes to develop novel Gpr151 antagonists to facilitate long-term abstinence in opioid-dependent individuals. Gpr151 is an orphan G-protein coupled receptor that is expressed almost exclusively in the medial habenula and co-localizes with ?-opioid receptors to regulate the inhibitory effects of opioids on habenular neurons. Mice with a null mutation in Gpr151 (Gpr151-/- mice) are resistant to the stimulant and rewarding effects of opioids and self-administer lower quantities of oxycodone. Based on this preliminary work, the study will seek to identify Gpr151 antagonists through a variety of methods and optimize them for potency, selectivity, drug metabolism, pharmacokinetics, and brain penetration properties. The study will evaluate effects of those with the most favorable drug-like physiochemical properties on electrophysiological responses of medial habenula to opioid drugs and assess the in vivo efficacy of these novel antagonists in wild-type and Gpr151-/- mice.

More than 100 million adults in the U.S. suffer from intermittent or constant chronic pain, and chronic pain affects at least 10 percent of the world’s population. The primary pharmaceuticals for treatment of chronic pain have been natural or synthetic opioids, and the use of opioids for pain treatment has resulted in what has been called an “epidemic” of opioid abuse, addiction, and lethal overdoses. Through a process of rational drug design, the research team has generated a new chemical entity (NCE) and have given it the name Kindolor, a non-opiate, non-addicting molecule that was shown to reduce or eliminate chronic pain in five animal models at doses compatible with use of Kindolor in humans. This project intends to complete the pre-clinical studies required for an IND application, which, if approved, would allow for proceeding onto the Phase 1 and 2 studies to assess safety and efficacy of the compound against osteoarthritic pain.

Responding to urgent calls for non-opioid treatment, this research group has been evaluating the therapeutic potential of cannabidiol (CBD), a non-intoxicating cannabinoid, for the treatment of some clinical aspects of opioid use disorder (OUD). Preclinical animal studies show that CBD decreases cue-induced heroin-seeking behavior during drug abstinence, associated with incubation of craving. Clinical work has also shown that CBD was safe in combination with a potent opioid agonist to address a potential relapse condition and decreased craving and anxiety associated with heroin cues in abstinent individuals with heroin use disorder. Building on this foundation, the researchers will investigate an oral CBD powered by a novel patented technology (leveraging the kinetics of long-chain fatty acid absorption) in a gelcap delivery system that improves bioavailability, reduces the incidence of gastrointestinal side effects, reduces first pass metabolism, and enhances onset time. This study could lead to the development of a non-opioid, non-intoxicating FDA-approved medication to reduce opioid craving and relapse and restore global functioning in individuals with OUD.

The ongoing epidemic of opioid use disorder (OUD), overdose, and death is unprecedented. Available pharmacologic therapies for OUD have failed to stem the tide, plagued by poor adherence and retention, the principal factors associated with relapse and treatment failure. More than 80 percent of individuals with OUD are untreated. More treatment options are needed. This proposal seeks to develop a better antagonist-based OUD pharmacotherapy for populations highly motivated to achieve abstinence, such as military personnel, criminal justice clients, and the currently employed. A series of novel and proprietary small molecules will be designed and synthesized to address the adherence problem by inducing effective opioid antagonism with a single injection lasting at least 2 months, and up to 4 months or more. The goal of this project is to advance to Phase 3 clinical trials toward FDA approval of our lead compound. If successful, this project could lead to a novel therapeutic with superior adherence and retention, resulting in a significant public health impact by reducing rates of relapse, overdose, and death.

Extended-release naltrexone (XR-NTX) reduces overdose risk; however, transitioning to XR-NTX requires detoxification, which is a major hurdle. Non-opioid detoxification with an alpha-2 adrenergic receptor agonist, such as lofexidine, may shorten detoxification time, but it does not reduce the subjective effects of withdrawal. Pregabalin potentiates the activity of glutamic acid decarboxylase, inhibits calcium influx and release of excitatory neurotransmitters, raises GABA levels, and is approved for neuropathic pain, for fibromyalgia, and as an adjunctive therapy for adults with partial onset seizures. The study will test whether pregabalin can be combined with lofexidine to better reduce the subjective effects of opioid withdrawal than lofexidine alone and increase the proportion of patients that transition to XR-NTX. Such a dosing combination could lower the detoxification hurdle for patients who are interested in antagonist treatment or who are in settings where it is unavailable or difficult to access.

There are no FDA-approved medications for stimulant use disorders, and therapies for opioid use disorders remain suboptimal in ways that are now a focus of national attention. Thus, there is a clear need to identify new targets and explore new approaches for addiction medication development. Several lines of evidence suggest that PTPRD (receptor type protein tyrosine phosphatase D) may be a promising target for development of pharmacotherapeutics to treat not only stimulant use disorders but opioid use disorders as well. This research will focus on improving existing PTPRD ligands, identifying their effects on the dopamine and opioid systems, and moving the best novel, patentable PTPRD ligands toward human studies. If successful, this project will generate novel, well-tolerated, and bioavailable PTPRD ligands that display in vitro potency, selectivity and stability, and in vivo modulation of both cocaine and opioid-mediated reward at doses that present no significant toxicity.

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 some of the key limitations, Intra-Cellular Therapies Inc (ITI) is developing ITI-333, a novel compound with high-affinity activity at mu opiate (MOP), 5-HT2A, and D1 receptors, that lacks abuse liability and thus offers great promise for the treatment of opioid use disorders. This proposal is for a 2-year UG3 program, including a first-in-human, single ascending dose (SAD) study to assess the safety, tolerability, and pharmacokinetics of ITI-333 in healthy volunteers. This study will then be repeated in a single-center in-patient study with the goal of determining a maximally- tolerated dose (MTD) and completed with human abuse liability and functional pharmacology studies. Together, the researchers believe this clinical development plan will inform further development of ITI-333 and the selection of a cogent Phase 3 clinical path toward FDA approval as a medication for the treatment of OUD.

Tens of thousands of people die each year from opioid overdose. Many of these people began taking opioids for pain. A critical treatment goal is to reduce the development of opioid dependence either by enhancing opioid analgesia so lower doses can be used or by blocking withdrawal symptoms. Current pharmacological treatments in these two categories, although effective, present serious limitations. The recent finding that reducing the signaling through mu-delta opioid heterodimers appears to enhance opioid antinociception and reduce dependence suggests that a blocker of mixed mu-delta receptors (MDOR antagonist) could be effective in reducing dependence by limiting opioid tolerance and preventing opioid withdrawal. This research group has developed a compound with that characteristic, called D24M, which preliminary studies have shown could reduce opioid dependence by enhancing opioid antinociception, reducing opioid tolerance, or directly inhibiting opioid withdrawal. They propose to extend this research by investigating whether it can reduce chronic pain in an animal model that mimics the clinical situation of pain patients who transition to dependence. If these studies are successful, they could lead to the development of an optimized drug ready for Investigational New Drug (IND) application and enable translational and clinical testing.

The current studies are designed to examine a novel approach to treating OUD, namely use of a vaccine (OXY-KLH) targeted against oxycodone, one of the most commonly misused prescription opioids, and a vaccine (M-KLH) targeted against heroin/morphine. The researchers will evaluate the safety, immunogenicity, and preliminary efficacy of OXY-KLH and M-KLH. Overall, the proposed studies will provide a great deal of information about the safety and potential efficacy of the vaccines in reducing the addiction liability of opioids, which will be administered in a controlled laboratory setting. If the outcomes of the proposed studies with OXY-KLH and M-KLH are favorable, development of the bivalent vaccine (OXY-KLH plus M-KLH) that will target oxycodone and heroin will proceed. The long-term goal of this research is to develop a multivalent vaccine directed against oxycodone, heroin, and other relevant opioids.

The expansion of opioid prescribing in recent years to better treat pain has markedly increased their usage and availability and fueled an epidemic of abuse. Up to 80 percent of addicts reported initiating their habit through prescriptions drugs. Decreasing opioid prescriptions would lower opioid exposure, with fewer people receiving the drugs and less drug available for diversion. Study investigators have identified a novel target in the brain, distinct from any of the traditional opioid receptors capable of mediating potent analgesia without the reward behavior and side effects seen with traditional opioids. They targeted this site with a series of arylepoxamides and have identified a clinical candidate (MP1000) and backup compound. MP1000 is a potent analgesic in a range of thermal, inflammatory, and neuropathic analgesic assays. It fails to show reward behavior and does not produce respiratory depression at doses 5-fold greater than its analgesic ED50. Chronic administration does not produce physical dependence or withdrawal when challenged with an antagonist. It shows no cross tolerance to morphine and can be co-administered to subjects already on opioids for pain to lower their opioid usage (i.e., opioid sparing), facilitating the eventual discontinuation of the opioid. If successful, this project could lead to the development of a viable alternative to current opioid-based analgesics with reduced side effects (such as reward and respiratory depression) compared to opioids.

To address the need for novel therapeutics for opioid use disorder (OUD), this research group identified ghrelin as an endogenous regulator of the mesocorticostriatal circuit, which contributes to the enhanced motivational attributes of addictive drugs and drug-associated cues. Ghrelin binds to the growth hormone secretagogue receptor 1? (GHS1?R) to transduce several physiological and behavioral processes, including the reward-related effects of opioid agonists. Systemic administration of a GHS1?R antagonist/inverse agonist dose-dependently attenuated self-administration of the addictive opioid analgesic oxycodone as well as oxycodone-seeking. This project proposes to employ a suite of validated rodent OUD models to define the preclinical profile for PF5190457, a selective GHS1?R antagonist/inverse agonist. PF5190457’s abuse liability, ability to suppress withdrawal and relapse-like behaviors, drug metabolism and pharmacokinetics, and brain penetrability in rats will be assessed. Phase 1 clinical studies in non–treatment seeking OUD participants will follow to assess the safety and tolerability of PF5190457.