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Khoury R, Grysman N, Gold J, Patel K, Grossberg GT. The role of 5 HT6-receptor antagonists in Alzheimer's disease: an update. Expert Opin Investig Drugs 2018; 27:523-533. [PMID: 29848076 DOI: 10.1080/13543784.2018.1483334] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Despite recent advances in Alzheimer's disease (AD) research, no breakthrough treatments have been discovered. Cholinesterase inhibitors and the NMDA-receptor antagonist memantine are currently the two approved symptomatic treatments for AD. 5-HT6 receptor antagonism has recently emerged as a promising treatment strategy to improve cognition in AD, with a modest side-effect profile. AREAS COVERED 5-HT6 receptors, exclusively found in the central nervous system, modulate primarily GABA and glutamate levels, facilitating the secondary release of other neurotransmitters including dopamine, noradrenaline, and acetylcholine, all of which are compromised in AD. This review discusses findings of preclinical and phase I-III clinical trials conducted with three major 5-HT6 receptor antagonists: idalopirdine, intepirdine, and SUVN-502, in the field of AD. EXPERT OPINION Despite early positive findings, larger phase-III trials have failed to demonstrate any statistically significant impact on cognition for both idalopirdine and intepirdine, as adjunct to cholinesterase inhibitors. Paradoxically, 5-HT6 receptor agonists have also been shown to have cognitive enhancing properties. Thus, a better understanding of the mechanism of action of the 5-HT6 receptor and its ligands is warranted. Investigating 5-HT6 receptor partial or inverse agonists may be promising in future AD trials.
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Affiliation(s)
- Rita Khoury
- a Department of Psychiatry and Behavioral Neuroscience , Saint Louis University School of Medicine , St. Louis , MO , USA
| | - Noam Grysman
- a Department of Psychiatry and Behavioral Neuroscience , Saint Louis University School of Medicine , St. Louis , MO , USA
| | - Jake Gold
- a Department of Psychiatry and Behavioral Neuroscience , Saint Louis University School of Medicine , St. Louis , MO , USA
| | - Kush Patel
- a Department of Psychiatry and Behavioral Neuroscience , Saint Louis University School of Medicine , St. Louis , MO , USA
| | - George T Grossberg
- a Department of Psychiatry and Behavioral Neuroscience , Saint Louis University School of Medicine , St. Louis , MO , USA
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Nirogi R, Shinde A, Kambhampati RS, Mohammed AR, Saraf SK, Badange RK, Bandyala TR, Bhatta V, Bojja K, Reballi V, Subramanian R, Benade V, Palacharla RC, Bhyrapuneni G, Jayarajan P, Goyal V, Jasti V. Discovery and Development of 1-[(2-Bromophenyl)sulfonyl]-5-methoxy-3-[(4-methyl-1-piperazinyl)methyl]-1H-indole Dimesylate Monohydrate (SUVN-502): A Novel, Potent, Selective and Orally Active Serotonin 6 (5-HT 6) Receptor Antagonist for Potential Treatment of Alzheimer's Disease. J Med Chem 2017; 60:1843-1859. [PMID: 28212021 DOI: 10.1021/acs.jmedchem.6b01662] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Optimization of a novel series of 3-(piperazinylmethyl) indole derivatives as 5-hydroxytryptamine-6 receptor (5-HT6R) antagonists resulted in identification of 1-[(2-bromophenyl)sulfonyl]-5-methoxy-3-[(4-methyl-1-piperazinyl)methyl]-1H-indole dimesylate monohydrate (5al, SUVN-502) as a clinical candidate for potential treatment of cognitive disorders. It has high affinity at human 5-HT6R (Ki = 2.04 nM) and selectivity over 100 target sites which include receptors, enzymes, peptides, growth factors, ion channels, steroids, immunological factors, second messengers, and prostaglandins. It has high selectivity over 5-HT2A receptor. It is orally bioavailable and brain penetrant with robust preclinical efficacy. The combination of 5al, donepezil, and memantine (triple combination) produces synergistic effects in extracellular levels of acetylcholine in the ventral hippocampus. Preclinical efficacy in triple combination and high selectivity over 5-HT2A receptors are the differentiating features which culminated in selection of 5al for further development. The Phase-1 evaluation of safety and pharmacokinetics has been completed, allowing for the initiation of a Phase-2 proof of concept study.
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Affiliation(s)
- Ramakrishna Nirogi
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Anil Shinde
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Rama Sastry Kambhampati
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Abdul Rasheed Mohammed
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Sangram Keshari Saraf
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Rajesh Kumar Badange
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Thrinath Reddy Bandyala
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Venugopalarao Bhatta
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Kumar Bojja
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Veena Reballi
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Ramkumar Subramanian
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Vijay Benade
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Raghava Choudary Palacharla
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Gopinadh Bhyrapuneni
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Pradeep Jayarajan
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Vinod Goyal
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
| | - Venkat Jasti
- Discovery Research, Suven Life Sciences Ltd , Serene Chambers, Road-5, Avenue-7, Banjara Hills, Hyderabad 500 034, India
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