Funded Projects

Naltrexone (NTX) has proven to be an important, safe, and effective therapy for helping patients overcome opioid use disorders (OUD) and for preventing overdose. Unfortunately, the therapeutic potential of NTX has been blunted by poor adherence. To combat this issue, a system must be developed to deliver NTX for longer durations than currently available and with a more patient-friendly format. To address this problem, we will develop a long-acting and bioabsorbable NTX subcutaneous implant for the treatment of OUD. The proposed research will (a) determine the optimal chemical preparation of NTX inside the implant, (b) optimize the composition and porosity of the drug delivery substrate, and (c) refine the surgical procedure and instrumentation to be used during implantation. Once the safety and efficacy of this novel NTX implant is established, we will conduct the necessary clinical trials. The proposed study is highly relevant to and complementary of other efforts, either in consideration or already deployed to stem the tide of the lingering opioid crisis. If successful, this solution has the potential to enhance health, lengthen life, and reduce illness and disability for those suffering from OUD.

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.

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 some of the key limitations, Intra-Cellular Therapies Inc (ITI) is developing ITI-333, a novel compound with high-affinity activity at mu opiate (MOP), 5-HT2A, and D1 receptors, that lacks abuse liability and thus offers great promise for the treatment of opioid use disorders. This proposal is for a 2-year UG3 program, including a first-in-human, single ascending dose (SAD) study to assess the safety, tolerability, and pharmacokinetics of ITI-333 in healthy volunteers. This study will then be repeated in a single-center in-patient study with the goal of determining a maximally- tolerated dose (MTD) and completed with human abuse liability and functional pharmacology studies. Together, the researchers believe this clinical development plan will inform further development of ITI-333 and the selection of a cogent Phase 3 clinical path toward FDA approval as a medication for the treatment of OUD.

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.

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.

Naltrexone (NTX) has been proven as an important, safe, and effective therapy in helping patients overcome opioid addition and in preventing overdose. Unfortunately, the therapeutic potential of NTX has been blunted by poor adherence. To combat this issue, a system must be developed to deliver NTX for longer durations than are currently available with a more patient-friendly format. The goal of this research is to optimize and scale up our laboratory PLGA-based microparticle formulations of NTX delivery (either 2 months or 7–10 days) and bridge it to a Phase 1 clinical trial. This innovation will result in a more patient-friendly format consisting of less painful injections and improved release kinetics. PLGA-based drug delivery systems have been used successfully in a number of small-molecule products and are the most widely utilized and studied biocompatible polymer systems in controlled release. Thus, the regulatory and development hurdles with the FDA will be lower than with other novel excipients or technologies. The significance of this research and product development is that the final outcome of this project will ultimately provide a new, readily viable, essential tool to help patients overcome opioid dependence.

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.

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.

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.

The United States has seen dramatic increases in fatal overdoses due to heroin, counterfeit prescription drugs, and cocaine adulterated with fentanyl or fentanyl-like analogs. Current medications may not be sufficient to address the opioid overdose epidemic. As a complementary strategy, the researchers plan to develop vaccines against fentanyl and fentanyl-like compounds to reduce their abuse liability and the growing incidence of fatal overdoses. This research team has already developed vaccines against heroin and oxycodone that stimulate the production of antibodies effective in reducing opioid distribution to the brain, opioid-induced behaviors, and opioid-induced respiratory depression and have identified a promising fentanyl vaccine candidate cued up for optimization. Successful completion of an anti-fentanyl vaccine development project could offer a long-lasting, safe, and cost-effective intervention complementary to medication-assisted treatment (MAT) and may reduce overdoses in opioid users as well as protect people in professions (e.g., law enforcement, airport security, postal workers) at risk of accidental exposure to fentanyl and fentanyl analogs.

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.