Funded Projects

This study will conduct preclinical and clinical assessments of the NMDA modulator NYX-783 for treatment of opioid drug-seeking and relapse to opioid use disorder (OUD). NYX-783, a novel small molecule being developed by Aptinyx, has shown evidence of safety/tolerability in Phase 1 studies and is currently in Phase 2 trials for post-traumatic stress disorder. This project will test the safety, tolerability, and pharmacokinetics (PK) of NYX-718 in morphine-maintained patients in residential settings and then conduct a combined inpatient (safety/tolerability/PK) / outpatient (preliminary efficacy) study testing NYX-783’s effects on opioid use and relapse, stress/cue reactivity, craving, and quality of life in OUD subjects maintained on standard extended release naltrexone over a 10-week period. Successful completion of these studies will set the stage for larger scale Phase 2/3 studies of efficacy in OUD that will ultimately be required for FDA approval of NYX-783 for the treatment of drug-seeking and relapse in OUD.

Although effective, current pharmacotherapies for opioid use disorder (OUD) present serious limitations. For example, methadone, a mu opioid receptor (MOP) full agonist, has significant abuse liability and causes withdrawal after chronic use, while buprenorphine (Bup), an MOP partial agonist and kappa opioid receptor (KOP) antagonist, produces limited respiratory depression and is less effective than methadone in reducing drug use, craving, and relapse. To address the limitation of currently available MATs, this project uses a phased plan that will fast-track the IND development of a next-generation medication for OUD based on small-molecule compounds targeting the nociception opioid receptor (NOP)—with no misuse or dependence liability—that have shown promising efficacy in reducing oxycodone intake in rhesus monkeys trained to self-administer, with efficacies similar to that of buprenorphine. The project’s ultimate goal is to file an IND application for an NOP agonist as a promising new approach to treat illicit and prescription OUD that may offer an alternative to buprenorphine.

Novel treatments for opioid use disorder are critically needed as the addiction and overdose crises continue. Neuromodulation is a promising supplemental treatment to standard care. The overarching project seeks to evaluate low-intensity focused ultrasound that targets the nucleus accumbens, a primary component of the brain’s reward neurocircuitry. This supplement will expand the number of participants in part of the study and will increase the project’s overall impact consistent with the original objectives and aims of the parent grant.

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. 

The nation’s opioid epidemic remains a public health emergency, marked by high rates of opioid use and misuse among adults and a correlated rising incidence of neonatal opioid withdrawal syndrome (NOWS) in infants exposed to opioids before they are born. There are currently no pharmacotherapies approved by the Food and Drug Administration (FDA) for the treatment of NOWS. This research will complete manufacturing and clinical trial activities to evaluate and support FDA approval of a pediatric-appropriate formulation of lofexidine, a non-opioid medication approved for mitigation of opioid withdrawal symptoms in adults, as a first line-therapy in NOWS patients through two clinical trials to (1) identify an optimal dosing regimen of lofexidine for treatment of NOWS, and (2) evaluate the risks and benefits of its use in improving withdrawal symptoms, limiting infant exposure to other off-label narcotic medications and shortening the infant’s overall stay in the hospital.

There are currently no medications approved by the U.S. Food and Drug Administration to treat methamphetamine use disorder, even though risky patterns of methamphetamine use and overdose deaths have increased in recent years. Research using animal models shows that immune molecules that latch onto methamphetamine (anti-methamphetamine antibodies) show promise in blocking the effects of the drug. This project aims to identify a long-acting monoclonal antibody targeted to methamphetamine and conduct development and safety studies to prepare for future testing of the antibody treatment in humans.

Opioid dependence is a leading cause of premature illness and death. Previous research suggests that a protein called G-protein coupled receptor (GPR88) controls many addiction-relevant behavioral and physiological actions of opioids. This research study will validate GPR88 as a drug target for opioid use disorder as well as develop novel, brain-penetrant GPR88-binding molecules with properties optimized for treating opioid dependence. This research is an initial step toward the goal of developing GPR88-binding molecules as novel therapeutics to facilitate abstinence in people dependent on opioids.

Given recent increases in co-use of opioids and methamphetamine, there is a dire need for novel treatment strategies that prevent relapse to drug use in both opioid use disorder (OUD) and methamphetamine use disorder (MUD). The localization of certain receptors for the neurotransmitter glutamate—metabotropic glutamate receptor subtypes 2 and 3 (mGlu2/3)—and the mechanism through which they transmit signals, strongly suggest that activation of both of these receptors will effectively treat multiple symptoms that contribute to relapse, such as responsiveness to drug cues, physical withdrawal symptoms, neuroinflammation, and sleep disturbances. This project seeks to evaluate molecules that can activate mGlu2/3 receptors without binding to the same site as glutamate (i.e., positive allosteric modulators) as a novel pharmacological treatment for preventing relapse to OUD. The research also will examine the potential of such modulators for treating MUD.

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.

High relapse rates among people with opioid use disorder (OUD) indicate that addiction involves appetitive pathways. Peripheral stimulation of the glucagon-like peptide-1 receptor (GLP-1R) “satiety” pathway could reduce heroin seeking and taking. Pretreatment with a GLP-1R agonist reduces heroin taking, seeking, and drug-induced reinstatement in rats. This project tests whether GLP-1R agonists can reduce relapse in humans with OUD. A pilot study will be conducted to determine whether once-daily treatment with the shorter acting GLP-1R agonist, liraglutide, can safely and effectively reduce cravings among OUD patients. Animal models will be used to test the efficacy and safety of a longer-acting GLP-1R agonist, semaglutide, and then a clinical trial will be conducted to test whether semaglutide will reduce relapse and use in animal models. If successful, the study will show that treatment with GLP-1R agonists can safely and effectively reduce opioid craving, seeking, and relapse.

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.

Although medications are available to treat opioid use disorder (OUD), adherence with treatment programs remains a problem. Nalmefene is an opioid receptor antagonist that was previously approved for treatment of opioid overdose–induced respiratory depression that has a longer duration of action than naloxone. AP007 is a unique formulation of nalmefene-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles that when injected intramuscularly continually releases an effective dose of nalmefene and thus reduces opioid cravings in OUD patients. This group is developing AP007 and will have a lead formulation selected based on in vitro release kinetics data and in vivo pharmacokinetics data in rats. The objectives of the project are to determine safety and efficacy of AP007 in a swine opioid use/withdrawal model, preliminary safety in a first-in-human Phase 1 study, and preliminary efficacy in a Phase 2a multidose study. These results will be used to develop Phase 2 human and Phase 3 clinical studies.