Funded Projects

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.

The ongoing opioid crisis has led to renewed concerns about the clinical prescription of addictive opioid analgesics. However, there are currently no suitable alternatives for treating severe or malignant pain. Studies of opioid signaling mechanisms in mice deficient in ?-arrestin have suggested that biased agonists displaying preferential activation of G-protein signaling over ?-arrestin signaling could offer a promising avenue for the development of opioid analgesics with a reduced adverse effects profile. However, there is no concluding evidence showing that such biased signaling can indeed be associated with reduced opioid side effects and, consequently, an improved safety profile. This research will address the need for preclinical data to rigorously evaluate this hypothesis with a program of in vivo studies to compare the effects of “balanced” opioids (morphine, oxycodone, and fentanyl) with that of the “biased” agonists PZM21 and two novel ligands provided by colleagues at the NIDA IRP in nonhuman primates. The results of these studies will provide critical information regarding the dependence liability of “biased” agonists that, in clinical practice, might be given on a repeated, or chronic, basis, potentially adding a powerful new tool for the safer management of severe or malignant pain.

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.

This project aims to develop a new way to stimulate the delta opioid receptor to treat withdrawal and abstinence from chronic opioid use. Withdrawal can cause pain, depression, and anxiety, which contribute to relapse. The research will test promising drug candidates in animal models with the intention of bringing at least one effective and safe compound to the final stage of drug development before human clinical trials can begin.

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.

Current opioid overdose treatment requires administration of naloxone by first responders, which requires timely identification of the overdose, the need for a rescue injection, and immediate availability of the medication. The development of a fail-safe treatment that would provide a life-saving dose of naloxone without the need for intervention by another party could significantly reduce mortality. The researchers aim to develop a new medical device comprising an implantable, closed-loop system that senses the presence of an opioid overdose, automatically administers a life-saving bolus injection of naloxone, and simultaneously alerts first responders.

Opioid use disorder (OUD) and opioid overdose (OD) are major health issues. Breathing can be restored after OD by naloxone, but its short half-life can require multiple administrations to reverse OD, and OD symptoms may return after initial reversal if illicit opioids are still present after the effects of naloxone have worn off. Additionally, while the standard treatment of OUD with buprenorphine and methadone reduces relapse and mortality, access and adoption are limited by dosage forms, metabolic liabilities, and potential for misuse and diversion. This study seeks to develop chemically novel, potent mu-opioid receptor (MOR) antagonists and low- and mid-efficacy partial agonists. Current lead counts can outcompete opioid overdoses in preclinical models with a longer half-life, a key naloxone liability for treating OD. The potent, low-efficacy partial agonists add a low opioid tone, diminishing the aversive effects of pure antagonists. These, and the mid-efficacy partial agonists, are leads to maintenance therapeutics for OUD.

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.

Often (around 40 percent of the time), individuals being treated for opioid use disorder (OUD) also have pain that interferes with daily life. This study builds on the prior development of a collaborative primary care approach, entitled TOPPS (Treating Opioid Patients’ Pain and Sadness), in which behavioral health specialists and primary care providers share a unified plan for addressing pain and depression in patients receiving buprenorphine. Building in preliminary work, researchers are conducting a randomized controlled trial of TOPPS compared to a health education contact-control condition among 250 persons with OUD recruited from two primary care-based buprenorphine programs, provided over 3 months and followed over 12 months. The study will examine whether this intervention changes how much pain interferes with daily functioning, the severity of pain, depression, and whether individuals stay in OUD treatment.

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.

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.