Funded Projects

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.

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.

Over 2 million Americans have an Opioid Use Disorder (OUD) and the risks associated with misuse of opioids have prompted a public health crisis. There are three effective FDA-approved drugs for medication assisted treatment (MAT) of OUD. However, while MAT can reduce overall OUD related mortality by as much as fifty percent, relapse and treatment discontinuation are common within the first 5 to 12 weeks of MAT. As longer treatment retention is correlated with better long-term outcomes, the development of an adjunctive medication to alleviate key psychiatric symptoms associated with treatment failure would address an important unmet need. This study seeks to evaluate the safety and efficacy of brexpiprazole as adjunctive treatment to buprenorphine/naloxone in OUD. If successful, this study could enhance the effectiveness of OUD treatments by extending the duration of treatment, thereby reducing the likelihood for relapse and overdose.

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.

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).

Fentanyl and its analogs are synthetic opioids that are 100 to 10,000 times more potent than morphine. Overdose from these opioids is extremely dangerous due to their ultra-potency and longer half-life than naloxone, the front-line treatment for fentanyl overdose. This research study will develop novel mu opioid receptor antagonists that bind to the same receptor as the opioid drugs and specifically counteract fentanyl and its analogs, thereby reversing the drugs’ acute toxicity more effectively and with fewer side effects than current treatments. The researchers will characterize novel fentanyl derivatives, identify promising compounds, and pursue preclinical development of these compounds as novel reversal agents against the acute toxicity of fentanyl. The goal is to file an Investigational New Drug application with the U.S. Food and Drug Administration.

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.

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 the main deficits in these treatments, the researchers will develop and optimize medications with longer duration of action that prevent and reverse the effects of opioids in a manner that is not surmounted by increasing doses of agonist. Their pilot studies in monkeys show that the pseudo irreversible MOR selective antagonist methocinnamox (MCAM) decreases heroin but not cocaine self-administration, decreases choice for remifentanil in a food/drug choice procedure, and reverses—as well as protects against—respiratory depression by heroin, with a single injection being effective for a week or longer. Bringing a medication like this to marketable fruition could significantly improve the treatment of OUD and save lives by providing insurmountable extended protection after rescue from overdose, including from ultra-potent fentanyl analogs.

Methadone is useful in the treatment of opioid dependence; however, methadone misuse and methadone-related fatalities have increased. Ensysce has created two complementary, novel technologies that can be applied to methadone. Their Trypsin Activated Abuse Protection (TAAP™) prodrugs are “enzyme-activated” to release clinically effective opioid drugs only when taken orally and exposed to the correct physiologic conditions, such as exposure to trypsin in the small bowel. Their multi-pill abuse resistance (MPAR™) feature involves in situ bioregulation of opioid delivery from the TAAP™ systems, enabling control over oral multi-dose pharmacokinetic profiles. It is envisaged that an R-methadone-TAAP™ prodrug would demonstrate similar reduced addiction liability as with other opioid-TAAP products. The objective of this proposal is to develop an R-methadone-TAAP™/MPAR™ drug through Phase 1 clinical studies and to translate R-methadone-TAAP™/MPAR™ results into humans, to ultimately reduce the misuse and oral overdose potential of methadone.

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.

Opioid use disorder (OUD) is a significant public health problem in the United States. Particularly troubling is the rapid evolution of an opioid epidemic within the past decade, characterized by a surge in unintentional overdose deaths involving synthetic opioids, such as fentanyl. The current standard of care for opioid overdose is reversal with opioid antagonist naloxone. Naloxone is effective at reversing overdose from prescription opioids and heroin, but less effective when combating fentanyl, due to fentanyl?s high potency. Therapeutic monoclonal antibodies (mAbs) against fentanyl could overcome this problem by specifically preventing the drug from entering the central nervous system, averting overdose and attenuating opioid-induced respiratory depression. This study will develop and design of laboratory protocols needed to establish a Good Manufacturing Practice (GMP) process, quality assurance protocol, and stability profile for a new human mAb against fentanyl. Subsequent production of current GMP material will enable Good Laboratory Practice (GLP) toxicology studies in rats and dogs and eventually a Phase I/IIa clinical trial. This material will also be used in final opioid-induced respiratory depression studies in mice and non-human primates to confirm therapeutic efficacy of final drug product. If successful, these activities will enable filing for an investigational new drug application for this mAb candidate with the FDA.

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.