Funded Projects

There are currently no FDA-approved treatments for cocaine use disorder (CUD) or co-occurring substance use disorder. High relapse rates pose a major obstacle to treatment, and this is due in part to the way that high drug cravings reduce individuals’ cognitive flexibility in situations where they are stressed or exposed to drug-related cues. These effects appear to be stronger in women with CUD than in men. Building on preliminary data that a drug called Guanfacine reverses these effects in women, but not in men, this 3-year pilot clinical study will test whether Guanfacine will reduce cocaine use and increase abstinence and will use laboratory challenges to determine whether it reduces cravings and enhances cognitive flexibility in stressful or drug-cue-related situations.

Chronic pain is a significant public health problem associated with tremendous personal and economic burden. First-line treatment consists of opioid medications, but despite only moderate efficacy and unpleasant side effects, rates of opioid prescriptions have quadrupled over the past 15 years, and this has contributed to high rates of misuse, overdose, and mortality. Clearly, alternative, or non-opioid strategies for treating pain are needed. In this context, “opioid-sparing” medications refer to compounds that can be combined with and enhance the analgesic effects of lower-dose opioids without increasing the rewarding properties of either drug. There is preclinical evidence suggesting that cannabidiol (CBD) may have the potential to function as “opioid-sparing” medications, but its ability to alter opioid-mediated analgesia in humans has yet to be determined. This proposal will fill this gap by conducting a double-blind, placebo-controlled, within-subject randomized crossover study of the effects of CBD and morphine co-administration on pain sensitivity and subjective reinforcement on 28 healthy males and females. This is the first known study to investigate the ability of CBD to alter morphine’s analgesic effects in humans. If successful, the model will have a lasting impact on our ability to develop and test medications that reduce our reliance on chronic use of opioid medications for pain relief.

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.

Currently no medications are approved by the U.S. Food and Drug Administration to treat cocaine use disorder, which compromises cognitive function associated with achieving goals such as working memory, the ability to update information, and mental flexibility. This project will test whether  stimulating dopamine activity in the brain with the drug rotigotine (approved to treat Parkinson’s disease) is effective for treating cocaine use disorder. Past research has also shown that rotigotine can improve nerve cell and cognitive function in Alzheimer’s disease. This project will conduct a clinical trial to test whether treatment with rotigotine combined with cognitive behavioral therapy can reduce cocaine use in people with cocaine use disorder.

This U54 Center will use translational research from brain to bedside as a tool for medication development in cocaine use disorder. Preclinical and early phase I clinical PK/PD data will provide information for go/no-go decisions on phase II–III clinical trials with medications that show promise for cocaine use disorder. The overall goal of this research is to create a center that can provide important preclinical and early phase I clinical data to NIDA and pharmaceutical industry partners on novel compounds for cocaine use disorder. The aims related to the theme of the center will be achieved through two cores and three projects: The Administrative Core serves as a general resource for the other projects and the Educational Core, including oversight of fiscal and compliance matters, and will oversee interactions with outside entities, including NIDA and the pharmaceutical industry. The Educational Core will focus on training translational researchers for medication development for addictions across the two institutions.

There is a need to develop a mu-opioid receptor (MOR) treatment with enhanced therapeutic effects and reduced undesirable effects. Recently, several highly selective and potent MOR modulators have been identified as novel leads for opioid use disorder treatment. They all showed more promising pharmacological profiles compared to other known drugs in this category. The current proposal will focus on further development of these leads for preclinical IND-enabling studies and dynamic drug discovery and development pipeline construction. This project plans to further validate therapeutic profiles of the current leads with self-administration and pharmacokinetic studies and expand the small-molecule library to build a dynamic drug discovery and development pipeline. Preclinical IND-enabling studies on the identified lead(s) will be conducted, and in vivo pharmacokinetics and pharmacodynamics profiles of the new hits will be compared with current leads to define the next generation of lead compound(s).

The widespread availability of fentanyl and other potent synthetic opioids has dramatically increased opioid-related fatal overdoses. This project will develop and manufacture immune molecules (monoclonal antibodies) to reverse and treat overdose from fentanyl by keeping it out of the brain. This research will advance promising results in animal studies (preventing and reversing fentanyl- and carfentanil-induced breathing problems and irregular heartbeat) to clinical testing in people with opioid use disorder and others at high risk of opioid overdose from accidental or deliberate exposure to fentanyl and fentanyl-like drugs.

Opioids remain the gold standard for treating moderate to severe pain, but their use is limited by numerous adverse effects, including tolerance, dependence, abuse, and overdose. Adverse effects could be avoided by combining an opioid with another drug, such that smaller doses of the opioid (in combination with another drug) produce the desired therapeutic effect. Direct-acting serotonin type 2 (5-HT2) receptor agonists interact in a synergistic manner with the opioid morphine to produce antinociceptive effects, suggesting a 5-HT2 receptor agonist could be combined with small amounts of an opioid to treat pain, thereby lowering the risk associated with larger doses. Unfortunately, very little is known about interactions between 5-HT2 receptor agonists and other opioids. The proposed studies will evaluate the therapeutic potential of mixtures of opioids and 5-HT2 receptor agonists using highly translatable and well-established procedures to characterize the antinociceptive, respiratory-depressant (overdose), positive-reinforcing (leading to misuse), and discriminative-stimulus (subjective) effects of drug mixtures as well as the impact of chronic treatment on the development of tolerance to and physical dependence on opioids. If successful, these studies will provide proof-of-concept for this innovative approach to pain treatment and evaluate the utility of targeting 5-HT receptors for analgesic drug development.

MCAM is a novel opioid antagonist that can be used for opioid overdose reversal and has advantages over naloxone, including a pseudo-irreversible interaction with the ?-opioid receptor and a longer duration of action. Studies in animal models demonstrate MCAM’s long duration of action against the reinforcing and respiratory-depressant effects of remifentanil and heroin, indicating that could be a better treatment option for opioid use disorder. This project studies the pharmacodynamics of MCAM through animal toxicity and safety studies to establish the necessary and sufficient conditions from which to establish MCAM’s safety and antagonist activity in animals and humans. MCAM may be able to prevent all actions of any ?-receptor opioid drug in humans for a longer period of time than any other antagonist given acutely.

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.

High rates of relapse and overdose deaths pose significant challenges to the treatment of Opioid Use Disorder (OUD). Anti-opioid immunotherapies (i.e., vaccines and monoclonal antibodies) have great potential to reduce long-term opioid use and overdose, with minimal risk of side effects, when used in conjunction with pharmacological treatments and/or behavioral therapies. The ability of an anti-opioid vaccine to induce antibodies that render an opioid less effective, or less rewarding, and protect from accidental overdose could provide an important therapeutic option for patients undergoing treatment for OUD. The goal of this collaborative study is to design, develop, and evaluate vaccines for use in the treatment of opioid use disorder

Novel treatments for opioid use disorder are urgently needed. Previous research has shown that angiotensin-converting enzyme (ACE) can control levels and activity of natural, “endogenous,” opioids in a way that might reduce the rewarding effects of opioids like fentanyl. ACE inhibitors have been used to treat hypertension for decades, with no evidence of addiction or dependence. This research will evaluate ACE effects on endogenous opioids toward generating new, domain-specific ACE inhibitors with optimized properties for treating opioid use disorder. The research will also test the behavioral impact of these compounds in preclinical models of opioid use disorder.