1
|
Huang P, Ho CK, Cao D, Inan S, Rawls SM, Li M, Huang B, Pagare PP, Townsend EA, Poklis JL, Halquist MS, Banks M, Zhang Y, Liu-Chen LY. NCP, a dual kappa and mu opioid receptor agonist, is a potent analgesic against inflammatory pain without reinforcing or aversive properties. J Pharmacol Exp Ther 2024; 389:JPET-AR-2023-001870. [PMID: 38409113 PMCID: PMC10949162 DOI: 10.1124/jpet.123.001870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/24/2024] [Accepted: 01/30/2024] [Indexed: 02/28/2024] Open
Abstract
While agonists of mu (MOR) and kappa (KOR) opioid receptors have analgesic effects, they produce euphoria and dysphoria, respectively. Other side effects include respiratory depression and addiction for MOR agonists and sedation for KOR agonists. We reported that 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-{[4'-(2'-cyanopyridyl)]carboxamido}cmorphinan (NCP) displayed potent KOR full agonist and MOR partial agonist activities (58%) with 6.5x KOR-over-MOR selectivity in vitro Herein, we characterized pharmacological effects of NCP in rodents. In mice, NCP exerted analgesic effects against inflammatory pain in both the formalin test and the acetic acid writhing test, with A50 values of 47.6 and 14.4 microg/kg (s.c.), respectively. The analgesic effects in the acetic acid writhing test were mediated by the KOR. NCP at doses much higher than those effective in reducing inflammatory pain did not produce antinociception in the hot plate and tail flick tests, inhibit compound 48/80-induced scratching, cause conditioned place aversion (CPA) or preference, impair rotarod performance, inhibit locomotor activity, cause respiratory depression, or precipitate morphine withdrawal. However, NCP (10~100 microg/kg) inhibited gastrointestinal transit with a maximum of ~40% inhibition. In MOR knockout mice, NCP caused CPA, demonstrating that its lack of CPA is due to combined actions on the MOR and KOR. Following s.c. injection, NCP penetrated into the mouse brain. In rats trained to self-administer heroin, NCP (1~320 microg/kg/infusion) did not function as a reinforcer. Thus, NCP produces potent analgesic effects via KOR without side effects except constipation. Therefore, dual full KOR/partial MOR agonists with moderate KOR-over-MOR selectivity may be promising as non-addictive analgesics for inflammatory pain. Significance Statement Developing non-addictive analgesics is crucial for reducing opioid overdose deaths, minimizing drug misuse, and promoting safer pain management practices. Herein, pharmacology of a potential non-addictive analgesic, NCP, is reported. NCP has full KOR agonist / partial MOR agonist activities with a 6.5 x selectivity for KOR over MOR. Unlike MOR agonists, analgesic doses of NCP do not lead to self-administration or respiratory depression. Furthermore, NCP does not produce aversion, hypolocomotion, or motor incoordination, side effects typically associated with KOR activation.
Collapse
Affiliation(s)
- Peng Huang
- Temple University Lewis Katz School of Medicine, United States
| | - Conrad K Ho
- Temple University Lewis Katz School of Medicine, United States
| | - Danni Cao
- Temple University Lewis Katz School of Medicine, United States
| | - Saadet Inan
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Lewis Katz School of Medicine, Temple University, United States
| | - Scott M Rawls
- Temple University Lewis Katz School of Medicine, United States
| | - Mengchu Li
- Virginia Commonwealth University School of Pharmacy, United States
| | - Boshi Huang
- Virginia Commonwealth University School of Pharmacy, United States
| | - Piyusha P Pagare
- Virginia Commonwealth University School of Pharmacy, United States
| | | | | | | | - Matthew Banks
- Virginia Commonwealth University School of Medicine, United States
| | - Yan Zhang
- Virginia Commonwealth University School of Pharmacy, United States
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research, Temple University Lewis Katz School of Medicine, United States
| |
Collapse
|
2
|
Pan M, Wang G, Zhou L, Xu Y, Yao L, Wu C, Mei C, Zhao Z, Sun D, Guan T, Chen Q, Shi M, Xu H, Zeng W, Li F, Yan R, Liu BC. Safety and effectiveness of HSK21542 for hemodialysis patients: a multiple ascending dose study. Front Pharmacol 2023; 14:1203642. [PMID: 37876731 PMCID: PMC10590914 DOI: 10.3389/fphar.2023.1203642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 09/22/2023] [Indexed: 10/26/2023] Open
Abstract
Background: HSK21542, a novel selective peripherally-restricted κ-opioid receptor agonist has been proven to be a safe and effective analgesic and antipruritic drug in both in vitro and in vivo studies. We aimed to evaluate its safety, pharmacokinetics and efficacy in hemodialysis patients over a 1-week treatment period, and to establish the optimal dosage for a further 12-week stage 2 trial. Methods: In this multiple ascending dose study, hemodialysis patients were randomly assigned to receive HSK21542 (0.05-0.80 μg/kg), or a placebo three times within 2.5 h at the end of each dialysis session for 1 week. Safety evaluations included reports of treatment-emergent adverse events (TEAEs); pharmacokinetics and efficacy outcomes were also assessed. Results: Among the 44 screened patients, 41 were enrolled and completed the trial. The overall incidence of TEAEs was higher in the HSK21542 group compared to the placebo group, with an incidence of 75.0%, 50.0%, 75.0%, and 88.9% in the range of 0.05-0.80 μg/kg. All TEAEs were grade 1 or 2 in severity. HSK21542 exhibited linear pharmacokinetics characteristics within the dose range 0.05-0.80 μg/kg, without drug accumulation after multiple-doses. Compared to the placebo, a significant decrease of the weekly mean Worst Itching Intensity Numerical Rating Scale was found in the HSK21542-0.30 μg/kg group (p = 0.046), but without significant improvement in the Skindex-16 score. Conclusion: HSK21542 was well tolerated in the dose range 0.05-0.80 μg/kg in hemodialysis patients. HSK21542-0.3 μg/kg exhibited promising efficacy in patients with moderate to severe pruritus and warrants a further Stage 2 trial. Clinical Trial Registration: https://clinicaltrials.gov/, identifier NCT04470154.
Collapse
Affiliation(s)
- Mingming Pan
- Department of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, China
| | - Guihua Wang
- Department of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, China
| | - Li Zhou
- Division of Nephrology, Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, China
| | - Yan Xu
- Department of Nephrology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Li Yao
- Department of Nephrology, The First Hospital of China Medical University, Shenyang, China
| | - Chaoqing Wu
- Department of Nephrology, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Changlin Mei
- Division of Nephrology, The Second Affiliated Hospital Navy Medical University, Shanghai, China
| | - Zhanzheng Zhao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Dong Sun
- Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Tianjun Guan
- Division of Nephrology, Zhongshan Hospital, Xiamen University, Xiamen, China
| | - Qinkai Chen
- Department of Nephrology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Ming Shi
- Department of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Hui Xu
- Division of Nephrology, Xiangya Hospital of the Central South University, Changsha, China
| | - Weifang Zeng
- Sichuan Haisco Pharmaceutical Co., Ltd., Chengdu, China
| | - Fangqiong Li
- Sichuan Haisco Pharmaceutical Co., Ltd., Chengdu, China
| | - Rui Yan
- Department of Nephrology, Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Bi-Cheng Liu
- Department of Nephrology, Zhong Da Hospital, Southeast University School of Medicine, Nanjing, China
| |
Collapse
|
3
|
Beck TC, Wilson EM, Wilkes E, Lee LW, Norris R, Valdebran M. Kappa opioid agonists in the treatment of itch: just scratching the surface? ITCH (PHILADELPHIA, PA.) 2023; 8:e0072. [PMID: 38099236 PMCID: PMC10720604 DOI: 10.1097/itx.0000000000000072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Chronic pruritus is a debilitating condition affecting 23-44 million Americans. Recently, kappa opioid agonists (KOAs) have emerged as a novel class of potent antipruritic agents. In 2021, the Food and Drug Administration approved difelikefalin (Korsuva) for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. Difelikefalin is a potent, peripherally restricted KOA that is intravenously available. Although promising, difelikefalin is currently available as an intravenous composition only, limiting the scope of use. Oral formulations of difelikefalin did not meet the primary endpoint criteria in recent phase 2 clinical trials; however, additional clinical studies are ongoing. The future for KOAs in the treatment of pruritus is encouraging. Orally active pathway-biased KOAs, such as triazole 1.1, may serve as viable alternatives with broader applications. Extended-release compositions, such as the TP-2021 ProNeura subdermal implant, may circumvent the pharmacokinetic issues associated with peptide-based KOAs. Lastly, dual-acting kappa opioid receptor agonist/mu opioid receptor antagonists are orally bioavailable and may be useful in the treatment of various forms of chronic itch. In this review, we summarize the results of KOAs in clinical and preclinical trials and discuss future directions of drug development.
Collapse
Affiliation(s)
- Tyler C. Beck
- Department of Dermatology and Dermatological Surgery, Medical University of South Carolina, Charleston, SC
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC
| | - Elena M. Wilson
- Department of Dermatology and Dermatological Surgery, Medical University of South Carolina, Charleston, SC
| | - Erik Wilkes
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Lara Wine Lee
- Department of Dermatology and Dermatological Surgery, Medical University of South Carolina, Charleston, SC
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC
| | - Russell Norris
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC
| | - Manuel Valdebran
- Department of Dermatology and Dermatological Surgery, Medical University of South Carolina, Charleston, SC
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC
| |
Collapse
|
4
|
Santino F, Gentilucci L. Design of κ-Opioid Receptor Agonists for the Development of Potential Treatments of Pain with Reduced Side Effects. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28010346. [PMID: 36615540 PMCID: PMC9822356 DOI: 10.3390/molecules28010346] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/13/2022] [Accepted: 12/25/2022] [Indexed: 01/04/2023]
Abstract
The κ-opioid receptor (KOR) has recently emerged as an alternative therapeutic target for the development of pain medications, without deleterious side effects associated with the μ-opioid receptor (MOR). However, modulation of KOR is currently under investigation for the treatment of depression, mood disorders, psychiatric comorbidity, and specific drug addictions. However, KOR agonists also trigger adverse effects including sedation, dysphoria, and hallucinations. In this respect, there is currently much debate on alternative paradigms. Recent effort has been devoted in search of biased ligands capable of selectively activating favorable signaling over signaling associated with unwanted side effects. On the other hand, the use of partial agonists is expected to allow the analgesia to be produced at dosages lower than those required to produce the adverse effects. More empirically, the unwanted central effects can be also avoided by using peripherally restricted agonists. In this review, we discuss the more recent trends in the design of KOR-selective, biased or partial, and finally, peripherally acting agonists. Special emphasis is given on the discussion of the most recent approaches for controlling functional selectivity of KOR-specific ligands.
Collapse
|
5
|
Kim BS, Inan S, Ständer S, Sciascia T, Szepietowski JC, Yosipovitch G. Role of kappa-opioid and mu-opioid receptors in pruritus: Peripheral and central itch circuits. Exp Dermatol 2022; 31:1900-1907. [PMID: 36054458 PMCID: PMC10087456 DOI: 10.1111/exd.14669] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 08/03/2022] [Accepted: 08/15/2022] [Indexed: 12/14/2022]
Abstract
Modern genetic approaches in animal models have unveiled novel itch-specific neural pathways, emboldening a paradigm in which drugs can be developed to selectively and potently target itch in a variety of chronic pruritic conditions. In recent years, kappa-opioid receptors (KORs) and mu-opioid receptors (MORs) have been implicated in both the suppression and promotion of itch, respectively, by acting on both the peripheral and central nervous systems. The precise mechanisms by which agents that modulate these pathways alleviate itch remains an active area of investigation. Notwithstanding this, a number of agents have demonstrated efficacy in clinical trials that influence both KOR and MOR signalling. Herein, we summarize a number of opioid receptor modulators in development and their promising efficacy across a number of chronic pruritic conditions, such as atopic dermatitis, uremic pruritus and beyond.
Collapse
Affiliation(s)
- Brian S Kim
- Kimberly and Eric J. Waldman Department of Dermatology, Mark Lebwohl Center for Neuroinflammation and Sensation, Marc and Jennifer Lipschultz Precision Immunology Institute, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Saadet Inan
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Sonja Ständer
- Department of Dermatology and Center for Chronic Pruritus, University Hospital Műnster, Műnster, Germany
| | | | - Jacek C Szepietowski
- Department of Dermatology, Venereology, and Allergology, Wroclaw Medical University, Wroclaw, Poland
| | - Gil Yosipovitch
- Dr Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, Miller School of Medicine, University of Miami, Miami, Florida, USA
| |
Collapse
|
6
|
Stefanucci A, Della Valle A, Scioli G, Marinaccio L, Pieretti S, Minosi P, Szucs E, Benyhe S, Masci D, Tanguturi P, Chou K, Barlow D, Houseknecht K, Streicher JM, Mollica A. Discovery of κ Opioid Receptor (KOR)-Selective d-Tetrapeptides with Improved In Vivo Antinociceptive Effect after Peripheral Administration. ACS Med Chem Lett 2022; 13:1707-1714. [PMID: 36385929 PMCID: PMC9661715 DOI: 10.1021/acsmedchemlett.2c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 10/13/2022] [Indexed: 11/29/2022] Open
Abstract
Peripherally active tetrapeptides as selective κ opioid receptor (KOR) agonists have been prepared in good overall yields and high purity following solid-phase peptide synthesis via Fmoc protection strategy. Structural modifications at the first and second position of the lead compound FF(d-Nle)R-NH2 (FE200041) were contemplated with aromatic side chains containing d-amino acids, such as (d)-pF-Phe, (d)-mF-Phe, (d)-oF-Phe, which led to highly selective and efficacious KOR agonists endowed with strong antinociceptive activity in vivo following intravenous (i.v.) and subcutaneous (s.c.) administration in the tail flick and formalin tests. These results suggest potential clinical applications in the treatment of neuropathic and inflammatory pain.
Collapse
Affiliation(s)
- Azzurra Stefanucci
- Dipartimento
di Farmacia, Università di Chieti-Pescara
“G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy
| | - Alice Della Valle
- Dipartimento
di Farmacia, Università di Chieti-Pescara
“G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy
| | - Giuseppe Scioli
- Dipartimento
di Farmacia, Università di Chieti-Pescara
“G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy
| | - Lorenza Marinaccio
- Dipartimento
di Farmacia, Università di Chieti-Pescara
“G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy
| | - Stefano Pieretti
- Istituto
Superiore di Sanità, Centro Nazionale Ricerca e Valutazione Preclinica e Clinica dei farmaci, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paola Minosi
- Istituto
Superiore di Sanità, Centro Nazionale Ricerca e Valutazione Preclinica e Clinica dei farmaci, Viale Regina Elena 299, 00161 Rome, Italy
| | - Edina Szucs
- Institute
of Biochemistry, Biological Research Centre, 6726 Szeged, Hungary
| | - Sandor Benyhe
- Institute
of Biochemistry, Biological Research Centre, 6726 Szeged, Hungary
| | - Domiziana Masci
- Department
of Basic Biotechnological Sciences, Intensivological and Perioperative
Clinics, Catholic University of Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | | | - Kerry Chou
- Department
of Pharmacology, College of Medicine, University
of Arizona, Tucson, Arizona 85724, United States
| | - Deborah Barlow
- Department
of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, United States
| | - Karen Houseknecht
- Department
of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, Maine 04005, United States
| | - John M. Streicher
- Department
of Pharmacology, College of Medicine, University
of Arizona, Tucson, Arizona 85724, United States
| | - Adriano Mollica
- Dipartimento
di Farmacia, Università di Chieti-Pescara
“G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy
| |
Collapse
|
7
|
The Latest FDA-Approved Pharmaceuticals Containing Fragments of Tailor-Made Amino Acids and Fluorine. Pharmaceuticals (Basel) 2022; 15:ph15080999. [PMID: 36015147 PMCID: PMC9416721 DOI: 10.3390/ph15080999] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/07/2022] [Accepted: 08/11/2022] [Indexed: 01/19/2023] Open
Abstract
Nowadays, the selective introduction of fluorine into bioactive compounds is a mature strategy in the design of drugs allowing to increase efficiency, biological half-life and bio-absorption. On the other hand, amino acids (AAs) represent one of the most ubiquitious classes of naturally occurring organic compounds, which are found in over 40% of newly marked small-molecule pharmaceutical drugs and medical formulations. The primary goal of this work is to underscore two major trends in the design of modern pharmaceuticals. The first is dealing with the unique structural characteristics provided by the structure of amino acids featuring an abundance of functionality and the presence of a stereogenic center, all of which bodes well for the successful development of targeted bioactivity. The second is related to fine-tuning the desired activity and pharmacokinetics by selective introduction of fluorine. Historically, both trends were developed separately as innovative and prolific approaches in modern drug design. However, in recent decades, these approaches are clearly converging leading to an ever-increasing number of newly approved pharmaceuticals containing both structural features of amino acids and fluorine.
Collapse
|
8
|
Weng HJ, Pham QTT, Chang CW, Tsai TF. Druggable Targets and Compounds with Both Antinociceptive and Antipruritic Effects. Pharmaceuticals (Basel) 2022; 15:ph15070892. [PMID: 35890193 PMCID: PMC9318852 DOI: 10.3390/ph15070892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/07/2022] [Accepted: 07/15/2022] [Indexed: 12/10/2022] Open
Abstract
Pain and itch are both important manifestations of various disorders, such as herpes zoster, atopic dermatitis, and psoriasis. Growing evidence suggests that both sensations have shared mediators, overlapping neural circuitry, and similarities in sensitization processes. In fact, pain and itch coexist in some disorders. Determining pharmaceutical agents and targets for treating pain and itch concurrently is of scientific and clinical relevance. Here we review the neurobiology of pain and itch and discuss the pharmaceutical targets as well as novel compounds effective for the concurrent treatment of these sensations.
Collapse
Affiliation(s)
- Hao-Jui Weng
- Department of Dermatology, Taipei Medical University-Shuang Ho Hospital, New Taipei City 23561, Taiwan;
- Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- International Ph.D. Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
| | - Quoc Thao Trang Pham
- International Ph.D. Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
- Department of Dermatology, Faculty of Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 70000, Vietnam
| | - Chia-Wei Chang
- Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan;
| | - Tsen-Fang Tsai
- Department of Dermatology, National Taiwan University Hospital, Taipei 100225, Taiwan
- Correspondence:
| |
Collapse
|
9
|
Dalefield ML, Scouller B, Bibi R, Kivell BM. The Kappa Opioid Receptor: A Promising Therapeutic Target for Multiple Pathologies. Front Pharmacol 2022; 13:837671. [PMID: 35795569 PMCID: PMC9251383 DOI: 10.3389/fphar.2022.837671] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Kappa-opioid receptors (KOR) are widely expressed throughout the central nervous system, where they modulate a range of physiological processes depending on their location, including stress, mood, reward, pain, inflammation, and remyelination. However, clinical use of KOR agonists is limited by adverse effects such as dysphoria, aversion, and sedation. Within the drug-development field KOR agonists have been extensively investigated for the treatment of many centrally mediated nociceptive disorders including pruritis and pain. KOR agonists are potential alternatives to mu-opioid receptor (MOR) agonists for the treatment of pain due to their anti-nociceptive effects, lack of abuse potential, and reduced respiratory depressive effects, however, dysphoric side-effects have limited their widespread clinical use. Other diseases for which KOR agonists hold promising therapeutic potential include pruritis, multiple sclerosis, Alzheimer’s disease, inflammatory diseases, gastrointestinal diseases, cancer, and ischemia. This review highlights recent drug-development efforts targeting KOR, including the development of G-protein–biased ligands, mixed opioid agonists, and peripherally restricted ligands to reduce side-effects. We also highlight the current KOR agonists that are in preclinical development or undergoing clinical trials.
Collapse
|