IUPHAR review - Data-driven computational drug repurposing approaches for opioid use disorder

Opioid Use Disorder (OUD) is a chronic and relapsing condition characterized by the misuse of opioid drugs, causing significant morbidity and mortality in the United States. Existing medications for OUD are limited, and there is an immediate need to discover treatments with enhanced safety and efficacy. Drug repurposing aims to find new indications for existing medications, offering a time-saving and cost-efficient alternative strategy to traditional drug discovery. Computational approaches have been developed to further facilitate the drug repurposing process. In this paper, we reviewed state-of-the-art data-driven computational drug repurposing approaches for OUD and discussed their advantages and potential challenges. We also highlighted promising repurposed candidate drugs for OUD that were identified by computational drug repurposing techniques and reviewed studies supporting their potential mechanisms of action in treating OUD.

Pharmacological Treatment of Alcohol Cravings

(1) Background: The treatment of substance addiction is challenging and has persisted for decades, with only a few therapeutic options. Although there are some recommendations for specific treatments for Alcohol Use Disorder (AUD), there is no specific medication used to treat alcohol cravings, which could benefit millions of patients that are suffering from alcoholism. Cravings, or the urge to use drugs, refer to the desire to experience the effects of a previously experienced psychoactive substance. (2) Methods: We included original studies of alcohol abuse or dependence extracted from a controlled, blind, pharmacological treatment study which presented measures and outcomes related to alcohol cravings. (3) Results: Specific drugs used for the treatment of alcoholism, such as Naltrexone and Acamprosate, have had the best results in relieving craving symptoms, as well as promoting abstinence. Baclofen and anticonvulsants such as Gabapentin and Topiramate have shown good results in promoting abstinence and the cessation of cravings. (4) Conclusions: Specific drugs used for the treatment of alcoholism to obtain the best results can be considered the gold standard for promoting abstinence and relieving cravings. Anticonvulsants and Baclofen also had good results, with these medications being considered as second-line ones. Varenicline is an option for alcohol dependents who also concomitantly ingest tobacco.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.

Olanzapine/Samidorphan: A New Combination Treatment for Schizophrenia and Bipolar I Disorder Intended to Reduce Weight Gain

Olanzapine is a second-generation antipsychotic with established efficacy in several psychiatric disease states, but its use is limited because of weight gain and metabolic side effects. Samidorphan is a novel opioid antagonist that binds to mu-opioid, kappa-opioid, and delta-opioid receptors and is hypothesized to reduce cravings for high-calorie foods thus attenuating antipsychotic-induced weight gain. The combination product olanzapine/samidorphan was approved by the US Food and Drug Administration in June 2021 for the treatment of schizophrenia and bipolar I disorder; this article reviews the pharmacological properties of oral olanzapine/samidorphan and its clinical efficacy and tolerability with a focus on mitigation of olanzapine-induced weight gain in these patient populations. In clinical trials, the combination of olanzapine/samidorphan was associated with significantly less weight gain and smaller increases in waist circumference as compared with olanzapine monotherapy. Olanzapine/samidorphan demonstrated similar efficacy as olanzapine monotherapy and was well tolerated. Weight gain and metabolic side effects associated with olanzapine monotherapy can result in tolerability issues and potentially medication nonadherence. Olanzapine/samidorphan is an effective treatment for schizophrenia and bipolar I disorder with less weight gain than olanzapine monotherapy.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

World Health Organization risk drinking level reductions are associated with improved functioning and are sustained among patients with mild, moderate and severe alcohol dependence in clinical trials in the United States and United Kingdom

AIMS

To examine whether World Health Organization (WHO) risk-level reductions in drinking were achievable, associated with improved functioning and maintained over time among patients at varying initial alcohol dependence severity levels. Design and setting Secondary data analysis of multi-site randomized clinical trials: the US Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) study and the UK Alcohol Treatment Trial (UKATT).

PARTICIPANTS

Individuals with alcohol dependence enrolled in COMBINE (n = 1383; 68.8% male) and seeking treatment for alcohol problems in UKATT (n = 742; 74.1% male). Interventions Naltrexone, acamprosate or placebo, and combined behavioral intervention or medication management in COMBINE. Social behavior network therapy or motivational enhancement therapy in UKATT.

MEASUREMENTS

WHO risk-level reductions were assessed via the calendar method. Alcohol dependence was measured by the Alcohol Dependence Scale, the Leeds Dependence Questionnaire and the Diagnostic and Statistical Manual of Mental Disorders. Measures of functioning included alcohol-related consequences (Drinker Inventory of Consequences and Alcohol Problems Questionnaire), mental health (Short Form Health Survey) and liver enzyme tests.

FINDINGS

One- and two-level reductions in WHO risk levels in the last month of treatment were maintained at the 1-year follow-up [adjusted odds ratio (OR), 95% confidence interval (CI) = one-level reduction in COMBINE: 3.51 (2.73, 4.29) and UKATT: 2.65 (2.32, 2.98)] and associated with fewer alcohol-related consequences [e.g. B, 95% CI = one-level reduction COMBINE: -26.22 (-30.62, -21.82)], better mental health [e.g. B, 95% CI = one-level reduction UKATT: 9.53 (7.36, 11.73)] and improvements in γ-glutamyltransferase [e.g. B, 95% CI = one-level reduction UKATT: -89.77 (-122.50, -57.04)] at the end of treatment, even among patients with severe alcohol dependence. Results were similar when abstainers were excluded. Conclusions Reductions in World Health Organization risk levels for alcohol consumption appear to be achievable, associated with better functioning and maintained over time in both the United States and the United Kingdom.

Investigational drugs for the treatment of binge eating disorder (BED): an update

Introduction: Binge eating disorder (BED) is the most common eating disorder and is frequently associated with psychiatric and medical comorbidities and functional impairment. Although psychological treatments have been the cornerstones of BED treatment, pharmacologic interventions also play an important part of the multimodal management of this condition.Areas covered: This review examines investigational, approved and other pharmacological agents for the treatment of BED. We searched PubMed and clinicaltrials.gov to identify pharmacological interventions for the management of this condition.Expert opinion: BED pharmacological studies have incorporated new drug targets based on our enhanced understanding of the pathophysiology of BED. Neurobiological dysregulation in the reward center and impulse control circuitry and related disturbances in dopamine neurotransmission are among the neurobiological explanations that have been suggested for BED. These mechanisms serve as a pharmacodynamic foundation for the development of new compounds such as lisdexamfetamine (LDX) and dasotraline. Despite these advances, pharmacological trials in BED have numerous challenges that must be overcome. For most compounds studied, larger and more definitive trials is a high priority.

Characterization of the Pharmacokinetics of Samidorphan in Healthy Volunteers: Absolute Bioavailability and the Effect of Food and Age

BACKGROUND AND OBJECTIVES

Samidorphan (SAM) is a novel μ-opioid receptor antagonist. We report clinical pharmacokinetic (PK) properties of SAM following different routes of administration, and the effects of food and age on the PK of SAM following oral administration in healthy volunteers.

METHODS

An open-label, fixed-sequence study (study 1, N = 10) examined the PK parameters following intravenous, sublingual, and oral exposure to SAM to determine absolute bioavailability. A double-blind, placebo-controlled study (study 2, N = 45) compared the PK in participants aged 18-40 years (cohort 1, n = 30) and ≥ 65 years (cohort 2, n = 15) who received a single oral dose of SAM 10 mg under fed (cohort 1 only) or fasted conditions.

RESULTS

In study 1, intravenous SAM had a plasma clearance of 33.7 L/h, volume of distribution of 341 L, and elimination half-life of 7-8 h. SAM was well-absorbed following sublingual or oral administration and reached peak concentrations (C_max) within 2 h, with absolute bioavailability of 71% (sublingual) and 69% (oral). In study 2, concentration-time profiles were similar under fed and fasted conditions (cohort 1) and for young and elderly participants from both cohorts; 90% confidence intervals for the geometric least squares mean ratios for C_max and area under the concentration-time curve from time zero extrapolated to infinity indicated equivalence.

CONCLUSIONS

SAM has high bioavailability that is comparable following sublingual and oral administration and is not subject to extensive first-pass metabolism. The PK of orally administered SAM are not affected by food or age.

A Review of Samidorphan: A Novel Opioid Antagonist

Opioid modulators have been explored as a treatment option for psychiatric disorders, but their use has been limited due to their abuse potential. Samidorphan (SAM), a μ-opioid receptor antagonist, has gained interest due to its favorable pharmacokinetic and pharmacodynamic profile. In this review article, six electronic databases including PubMed, PsycINFO, PsycARTICLES, Scopus, Web of Science, and CINAHL were searched to find relevant human studies with a focus on different clinical aspects of SAM. SAM was used in combination with buprenorphine (BUP) to counteract the abuse potential while still maintaining effectiveness in the treatment of depression. The BUP/SAM 2 mg/2mg combination improved depression in patients with major depressive disorder (MDD). SAM's ability to mitigate the weight gain associated with olanzapine (OLZ) has also been explored. Initial studies have shown promising results in some parameters of alcohol-use disorder, while no significant benefit in the treatment of binge-eating disorder has been reported. Somnolence and gastrointestinal side effects were the most commonly observed side effects of SAM.

Prospects for pharmacotherapies to treat alcohol use disorder: an update on recent human studies

PURPOSE OF REVIEW

The aim of this study was to provide an update on medication development efforts for alcohol use disorder (AUD) by reviewing recently published (past 2 years) human studies that evaluated medications' effects on alcohol-related outcomes.

RECENT FINDINGS

Forty-five publications were found suitable for this review. A variety of compounds have been tested in the past 2 years as potential pharmacological options for AUD, including medications that act on multiple targets (topiramate, aripiprazole, quetiapine), calcium channels (gabapentin), gamma-Aminobutyric acid receptors (baclofen, diazepam), glutamate receptors (ifenprodil, memantine, glycine), nicotinic acetylcholine receptors (varenicline, mecamylamine), α1 adrenergic receptors (prazosin, doxazosin), neuroendocrine pathways (oxytocin, a vasopressin receptor 1b antagonist, a ghrelin receptor inverse agonist) and others (samidorphan, ibudilast, N-acetylcysteine, citoline). Important findings and limitations regarding the effects of these medications on alcohol-related outcomes are discussed.

SUMMARY

There is a critical need to increase the armamentarium of medications for AUD. Human laboratory studies may help screen and prioritize promising targets and compounds before running large clinical trials. Given the complexity of AUD and the heterogeneity of afflicted patients, future studies should also investigate potential moderators and predictors of response to each pharmacological intervention.

Mitigation of Olanzapine-Induced Weight Gain With Samidorphan, an Opioid Antagonist: A Randomized Double-Blind Phase 2 Study in Patients With Schizophrenia

OBJECTIVE

Preclinical evidence and data from a proof-of-concept study in healthy volunteers suggest that samidorphan, an opioid antagonist, mitigates weight gain associated with olanzapine. This study prospectively compared combination therapy of olanzapine plus either samidorphan or placebo for the treatment of schizophrenia.

METHODS

This was an international, multicenter, randomized phase 2 study of olanzapine plus samidorphan in patients with schizophrenia. The study had a 1-week open-label olanzapine lead-in period followed by a 12-week double-blind treatment phase in which patients were randomly assigned in a 1:1:1:1 ratio to receive olanzapine plus placebo (N=75) or olanzapine plus 5 mg (N=80), 10 mg (N=86), or 20 mg (N=68) of samidorphan. The primary aims were to confirm that the antipsychotic efficacy of olanzapine plus samidorphan was comparable to olanzapine plus placebo, to assess the effect of combining olanzapine with samidorphan on olanzapine-induced weight gain, and to assess the overall safety and tolerability of olanzapine plus samidorphan.

RESULTS

Antipsychotic efficacy, as assessed by total score on the Positive and Negative Syndrome Scale (PANSS), was equivalent across all treatment groups. Treatment with olanzapine plus samidorphan resulted in a statistically significant lower weight gain (37% lower weight gain compared with olanzapine plus placebo). The least square mean percent change from baseline in body weight was 4.1% (2.9 kg) for the olanzapine plus placebo group and 2.6% (1.9 kg) for the olanzapine plus samidorphan group (2.8% [2.1 kg] for the 5 mg group, 2.1% [1.5 kg] for the 10 mg group, and 2.9% [2.2 kg] for the 20 mg group). Adverse events reported at a frequency ≥5% in any of the olanzapine plus samidorphan groups and occurring at a rate ≥2 times greater than in the olanzapine plus placebo group were somnolence, sedation, dizziness, and constipation. Other safety measures were comparable between the olanzapine plus samidorphan groups and the olanzapine plus placebo group.

CONCLUSIONS

The antipsychotic efficacy of olanzapine plus samidorphan was equivalent to that of olanzapine plus placebo, and olanzapine plus samidorphan was associated with clinically meaningful and statistically significant mitigation of weight gain compared with olanzapine plus placebo. Olanzapine plus samidorphan was generally well tolerated, with a safety profile similar to olanzapine plus placebo.

Maintenance of World Health Organization Risk Drinking Level Reductions and Posttreatment Functioning Following a Large Alcohol Use Disorder Clinical Trial

Background

Reductions in the World Health Organization (WHO) risk drinking levels have been proposed as an alternative primary outcome for alcohol clinical trials. Yet, little is known about whether reductions in WHO risk drinking levels can be maintained over time. The current study examined whether reductions in WHO risk drinking levels were maintained for up to 1 year following treatment, and whether reductions over time were associated with improvements in functioning.

Methods

Secondary data analysis of individuals with alcohol dependence (n = 1,226) enrolled in the COMBINE study, a multisite, randomized, placebo‐controlled clinical trial. Logistic regression was used to examine the maintenance of end‐of‐treatment WHO risk level reductions and WHO risk level reductions at the 1‐year follow‐up. Repeated‐measures mixed models were used to examine the association between WHO risk level reductions and functional outcomes over time.

Results

Achieving at least a 1‐ or 2‐level reduction in risk by the end of treatment was significantly associated with WHO risk level reductions at the 1‐year follow‐up assessment (p < 0.001). Among individuals who achieved at least a 1‐level reduction by the end of treatment, 85.5% reported at least a 1‐level reduction at the 1‐year follow‐up. Among individuals who achieved at least a 2‐level reduction by the end of treatment, 77.8% reported at least a 2‐level reduction at the 1‐year follow‐up. WHO risk level reductions were associated with significantly lower alcohol consumption, better physical health (p < 0.01), and fewer alcohol‐related consequences (p < 0.001) up to 1 year following treatment.

Conclusions

One‐ and 2‐level reductions in WHO risk levels during alcohol treatment were maintained after treatment and associated with better functioning over time. These findings support the use of the WHO risk level reductions as an outcome measure that reflects clinically significant improvement in how individuals seeking treatment for alcohol use disorder feel and function.