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.

Several abuse-deterrent opioid products (primarily formulations) are currently marketed or in clinical development, but they fall short of being resistant to abuse. Rather than abuse-deterrent formulations, this project, in partnership with Ensyce Biosciences, has created two complementary, novel technologies that control the release of known opioids. One technology delivers prodrugs — drugs that are not active until they have been exposed to the right conditions within the body, at which point they are gradually converted into active drugs, making them difficult to tamper with and reducing the potential for misuse. Another technology makes it so that taking increasing numbers of pills inhibits the process of converting prodrug into active drug, reducing the potential for overdose. This project aims to refine the development of these two technologies and work to combine them, and to translate promising animal results into human use.

The adverse effects of morphine and other mu-opioid receptor (MOR) agonists are linked to the ?-arrestin pathway, while analgesia is tied to the G-protein pathway. Pathway specific or “biased” drug development can target G-protein specific agonists that avoid the negative consequences of ?-arrestin signaling activation and produce analgesia. Highly “biased” MOR agonists have promise as effective analgesics but devoid of opioid-induced adverse effects. Preclinical studies compared two compounds, MEB-1166 and MEB-1170, against Oliceridine and morphine. Both compounds displayed no respiratory depression, even at high doses, while morphine and Oliceridine significantly reduced respiratory function. In contrast to morphine, neither MEB-1166 nor MEB-1170 produced conditioned place preference, suggesting an absence of abuse liability. This study will characterize the pharmaceutical and pharmacological profiles and perform liability studies for these compounds.

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.

Difficulty breathing is a hallmark symptom of an opioid-related overdose and can result in permanent brain injury or death within minutes. This project will develop a community-deployable Automated External Respiration System device that can restore and sustain breathing in people experiencing opioid-induced respiratory depression. The device stimulates the phrenic nerve in the chest that controls breathing until other medical interventions are available or the patient recovers. The research will develop and validate the automated external respiration system for testing in human research participants and ultimately aims to develop a system usable in a community setting.

Currently there are no safe, rapidly acting treatments for methamphetamine use disorder and overdose. This project will evaluate a potential treatment: the small molecule CS-1103, which selectively attaches to methamphetamine in the blood. This molecule quickly removes methamphetamine blood and into urine for elimination from the body. The research will evaluate the safety and compatibility of CS-1103 with the human body, toward future clinical testing in humans. 

Kinoxis has developed a novel small-molecule lead, KNX100, that reduces the severity of opioid withdrawal symptoms in preclinical animal models of opioid use disorder (OUD). KNX100 was discovered from a phenotypic screen of compounds derived from a fragment-based drug discovery program targeting the brain oxytocin system. KNX100 has a favorable pharmacokinetic and safety profile and has undergone testing for efficacy signals in two rodents and two non-human primate species. The proposed activity is to progress the development of KNX100 to treat opioid withdrawal in OUD. The overall objective of the project is to establish the safety and tolerability of KNX100 to enable human efficacy testing to commence in patients requiring treatment for opioid withdrawal. The long-term objective for this development program is to generate human efficacy data to support KNX100 as a potential treatment for opioid withdrawal symptoms and ultimately enable a New Drug Application to the FDA.

There is an urgent need to prevent and reduce opioid use disorder (OUD) by reducing the need for opioid analgesia and preventing the escalation of opioid dosing in patients at greater risk of using more opioids following surgery. Brivoligide is a non-opioid drug candidate that can alter the course of postoperative pain for patients most likely to suffer increased pain and utilize more opioids following surgery. A single administration of brivoligide at the time of surgery can reduce acute postoperative pain in these patients by 30 percent to 40 percent beyond what can be achieved with the current standard of care for at least 28 days and reduce opioid utilization by 40 percent over a 3-month period following surgery. This project will support the research necessary to achieve regulatory approval of brivoligide with a broad indication, which will initially focus on the reduction of postoperative pain following mastectomy, a soft-tissue surgery model suitable to detect long-term pain and opioid reduction benefits. Brivoligide appears to be a very promising pharmacotherapy with the potential to greatly contribute to stemming the tide in the opioid crisis.

In order to address the opioid crisis, this group has developed a candidate heroin/opioid vaccine that induces antibodies that bind heroin/opioid upon injection and subsequently prevent the drug from crossing the blood-brain barrier and interacting with the brain's µ-opioid receptor. They completed pre-clinical testing of the vaccine candidate in mice and rats and demonstrated that the animals were protected from subcutaneous and intravenous heroin challenge. Ongoing durability studies have demonstrated that antibody titer and protective efficacy were maintained 6 months after the last vaccination. This project proposes to advance the development of the vaccine candidate by conducting a Phase I/IIa human clinical trial, by performing vaccine synthesis, nonclinical studies, and then a clinical trial. The supplemental award will allow for testing the efficacy of fentanyl haptens and of the combination heroin–fentanyl vaccine.

Opioids have been significantly over-prescribed and are associated with numerous deaths, resulting in the nation’s current opioid crisis. The FDA recently approved the ?2 adrenergic agonist lofexidine as a non-addictive, non-opioid treatment for opioid use disorder (OUD), but there is a continued, urgent need to develop additional pharmacological alternatives to address both pain and OUD. The psychoactive, natural product, Mitragyna speciosa (kratom), has triggered significant interest in this space because Mitragynine, its main alkaloid, can interact with both mu opioid and ?2 receptors, offering a totally new approach for treating OUD. This project involves the synthesis and research of a series of Mitragynine analogs to better understand the pharmacological mechanisms that underlie Mitragynine’s opioid and adrenergic activities. If successful, this project will result in templates for the design of novel opioid receptor ligands. This advance would greatly improve the knowledge of interactions of these structurally novel compounds with opioid receptors and facilitate the development of these ligands as treatments for 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.