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Role of residual CB1 receptor agonist activity in the hemodynamic profile of CB2 agonists
e18
Abstracts
value of secondary pharmacology profiling data on projects in discovery and development. doi:10.1016/j.vascn.2011.03.064
Poster No: 59 Rational design of an in vitro safety profiling panel to reduce undesired secondary pharmacology of drug candidates Steven Whitebread a, Joanne Bowes b, Andrew Brown c, Jacques Hamon d, Wolfgang G. Jarolimek e, Gareth Waldron f, Arun Sridhar c a
Novartis Institutes for Biomedical Research, Cambridge, MA, USA AstraZeneca, Macclesfield, Cheshire, United Kingdom c GlaxoSmithKline, Ware, Herts, United Kingdom d Novartis Institutes for Biomedical Research, Basel, BS, Switzerland e Pharmaxis, Frenchs Forest, NSW, Australia f Pfizer, Sandwich, Kent, United Kingdom
selectivity, ABT-961, A-836339, cannabinor and WIN55,212-2, were tested in conscious telemetry mice. All four CB agonists produced large decreases in MAP and HR. Subsequently, the CB agonists were administered to mice pretreated with the CB1 antagonist AM-251, which abolished the CV effects of WIN55,212-2 and A-836339, but had no effect on ABT-961 or cannabinor. The role of residual CB1 receptor activity was further assessed in CB1 receptor knockout mice. Consistent with the pharmacological studies, the CV effects of WIN55,212-2 and A-836339 were absent in CB1 receptor knockout mice, whereas the effects of ABT-961 persisted. Surprisingly, cannabinor had no CV effect in the knockout mice, in contrast to the antagonist studies. These findings suggest that only low level CB1 activation is required to elicit CV effects, resulting in a narrower in vivo therapeutic index than would be predicted by the in vitro profile.
b
Off-target related adverse drug reactions (ADRs) of compounds brought to clinical development and the market impose substantial risks to patients. In vitro secondary pharmacology profiling is used in drug discovery to identify potential undesirable ADRs mediated by molecular targets distinct from the primary therapeutic target. The early use of high-throughput in vitro functional cell-based, binding and enzyme activity assays for secondary pharmacology has substantially increased the value of such data in compound design and candidate drug selection, as well as in the mechanistic understanding of in vivo safety pharmacology, toxicology and clinical observations. Here, the knowledge of four pharma companies has been combined to recommend a minimum panel of secondary pharmacology targets. The targets have been selected for their known link with undesirable ADRs based on the analysis of compound profiles, and clinical and translational data sets. Hit rate and coverage of biological space were also important properties for the selection of the targets. Hit rates (>50% effect at 10 μM or pIC50/ pEC50 > 5) were measured for diverse sets of compounds (>2000) in each company and compared to identify promiscuous targets. The advantages or disadvantages of the various technologies used are highlighted. The output of this exercise is an annotated minimum panel of molecular targets for use in secondary pharmacology profiling as best practice in drug discovery. doi:10.1016/j.vascn.2011.03.065
Poster No: 60 Role of residual CB1 receptor agonist activity in the hemodynamic profile of CB2 agonists Patricia N. Banfor, Philip Zocharski, Betty Yao, Michael Dart, Michael Meyer, Andrew King Abbott Laboratories, Abbott Park, IL, USA Cannabinoids (CB) mediate physiological responses by activation of CB1 or CB2 receptors. Non-selective CB agonists produce analgesia but also produce adverse cardiovascular (CV) and CNS effects. These side effects are via activation of CB1 receptors. Thus, selective CB2 agonists offer therapeutic analgesic potential without CV liability. However, numerous Abbott highly selectively CB2 agonists produced decreases in mean arterial pressure (MAP) and heart rate (HR) in preclinical testing. The purpose of these experiments was to investigate if residual CB1 activity was responsible for these effects. The CV effects of four CB agonists with varying receptor subtype
doi:10.1016/j.vascn.2011.03.066
Poster No: 61 Investigation of the in vivo safety significance of potent off-target in vitro muscarinic receptor binding Deborah Widomski, Jason Segreti, Kathy Kohlhaas, Kelly Larson, Gilbert Diaz, Michael Schrimpf, Lance Lee, Timothy Esbenshade, James Polakowski, Andrew King Abbott Laboratories, Abbott Park, IL USA Compound X demonstrated a high-level of off-target binding to muscarinic M1, M2 and M3 receptors in a high-throughput receptor selectivity profile. Further in-vitro testing revealed that compound X acted as an antagonist at human recombinant muscarinic receptors. We assessed the in-vivo safety significance of this. Functional in-vivo M1, M2 and M3 receptor antagonism was assessed in rats by determining the ability of X to block the decrease in body temperature, heart rate and arterial pressure, respectively, produced by muscarinic agonists. Pretreatment with compound X had no effect on the hypothermia nor the bradycardia or hypotension induced by the muscarinic agonist. In contrast, these responses were abolished by known muscarinic antagonists. The principal safety liabilities associated with muscarinic receptor antagonism include cardiovascular and gastrointestinal side effects. To further investigate this, the effects of compound X were assessed in the conscious telemetry-instrumented rat, and also in a rat model of gastrointestinal transit time. In contrast to the dose-dependent tachycardia and reduction in transit time induced by atropine, compound X had no significant effect up to and including the highest doses tested. Combined, these results suggest that compound X does not act as a functional antagonist of M1–3 receptors in-vivo in the rat even at very high multiples of the predicted human efficacious Cmax. In addition, this study demonstrates the importance of assessing the safety significance of in-vitro selectivity findings with in-vivo mechanistic evaluation. doi:10.1016/j.vascn.2011.03.067
Poster No: 62 Rotarod performance as a functional biomarker of musculoskeletal syndrome for in vivo screening in LI/LO Suzanne Nodop Mazurek, Paul Harrison, Jun Li, Gerald Nabozny, Glenn Reinhardt, Ryan Fryer Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, Ridgefield, CT, USA
Abstracts
value of secondary pharmacology profiling data on projects in discovery and development. doi:10.1016/j.vascn.2011.03.064
Poster No: 59 Rational design of an in vitro safety profiling panel to reduce undesired secondary pharmacology of drug candidates Steven Whitebread a, Joanne Bowes b, Andrew Brown c, Jacques Hamon d, Wolfgang G. Jarolimek e, Gareth Waldron f, Arun Sridhar c a
Novartis Institutes for Biomedical Research, Cambridge, MA, USA AstraZeneca, Macclesfield, Cheshire, United Kingdom c GlaxoSmithKline, Ware, Herts, United Kingdom d Novartis Institutes for Biomedical Research, Basel, BS, Switzerland e Pharmaxis, Frenchs Forest, NSW, Australia f Pfizer, Sandwich, Kent, United Kingdom
selectivity, ABT-961, A-836339, cannabinor and WIN55,212-2, were tested in conscious telemetry mice. All four CB agonists produced large decreases in MAP and HR. Subsequently, the CB agonists were administered to mice pretreated with the CB1 antagonist AM-251, which abolished the CV effects of WIN55,212-2 and A-836339, but had no effect on ABT-961 or cannabinor. The role of residual CB1 receptor activity was further assessed in CB1 receptor knockout mice. Consistent with the pharmacological studies, the CV effects of WIN55,212-2 and A-836339 were absent in CB1 receptor knockout mice, whereas the effects of ABT-961 persisted. Surprisingly, cannabinor had no CV effect in the knockout mice, in contrast to the antagonist studies. These findings suggest that only low level CB1 activation is required to elicit CV effects, resulting in a narrower in vivo therapeutic index than would be predicted by the in vitro profile.
b
Off-target related adverse drug reactions (ADRs) of compounds brought to clinical development and the market impose substantial risks to patients. In vitro secondary pharmacology profiling is used in drug discovery to identify potential undesirable ADRs mediated by molecular targets distinct from the primary therapeutic target. The early use of high-throughput in vitro functional cell-based, binding and enzyme activity assays for secondary pharmacology has substantially increased the value of such data in compound design and candidate drug selection, as well as in the mechanistic understanding of in vivo safety pharmacology, toxicology and clinical observations. Here, the knowledge of four pharma companies has been combined to recommend a minimum panel of secondary pharmacology targets. The targets have been selected for their known link with undesirable ADRs based on the analysis of compound profiles, and clinical and translational data sets. Hit rate and coverage of biological space were also important properties for the selection of the targets. Hit rates (>50% effect at 10 μM or pIC50/ pEC50 > 5) were measured for diverse sets of compounds (>2000) in each company and compared to identify promiscuous targets. The advantages or disadvantages of the various technologies used are highlighted. The output of this exercise is an annotated minimum panel of molecular targets for use in secondary pharmacology profiling as best practice in drug discovery. doi:10.1016/j.vascn.2011.03.065
Poster No: 60 Role of residual CB1 receptor agonist activity in the hemodynamic profile of CB2 agonists Patricia N. Banfor, Philip Zocharski, Betty Yao, Michael Dart, Michael Meyer, Andrew King Abbott Laboratories, Abbott Park, IL, USA Cannabinoids (CB) mediate physiological responses by activation of CB1 or CB2 receptors. Non-selective CB agonists produce analgesia but also produce adverse cardiovascular (CV) and CNS effects. These side effects are via activation of CB1 receptors. Thus, selective CB2 agonists offer therapeutic analgesic potential without CV liability. However, numerous Abbott highly selectively CB2 agonists produced decreases in mean arterial pressure (MAP) and heart rate (HR) in preclinical testing. The purpose of these experiments was to investigate if residual CB1 activity was responsible for these effects. The CV effects of four CB agonists with varying receptor subtype
doi:10.1016/j.vascn.2011.03.066
Poster No: 61 Investigation of the in vivo safety significance of potent off-target in vitro muscarinic receptor binding Deborah Widomski, Jason Segreti, Kathy Kohlhaas, Kelly Larson, Gilbert Diaz, Michael Schrimpf, Lance Lee, Timothy Esbenshade, James Polakowski, Andrew King Abbott Laboratories, Abbott Park, IL USA Compound X demonstrated a high-level of off-target binding to muscarinic M1, M2 and M3 receptors in a high-throughput receptor selectivity profile. Further in-vitro testing revealed that compound X acted as an antagonist at human recombinant muscarinic receptors. We assessed the in-vivo safety significance of this. Functional in-vivo M1, M2 and M3 receptor antagonism was assessed in rats by determining the ability of X to block the decrease in body temperature, heart rate and arterial pressure, respectively, produced by muscarinic agonists. Pretreatment with compound X had no effect on the hypothermia nor the bradycardia or hypotension induced by the muscarinic agonist. In contrast, these responses were abolished by known muscarinic antagonists. The principal safety liabilities associated with muscarinic receptor antagonism include cardiovascular and gastrointestinal side effects. To further investigate this, the effects of compound X were assessed in the conscious telemetry-instrumented rat, and also in a rat model of gastrointestinal transit time. In contrast to the dose-dependent tachycardia and reduction in transit time induced by atropine, compound X had no significant effect up to and including the highest doses tested. Combined, these results suggest that compound X does not act as a functional antagonist of M1–3 receptors in-vivo in the rat even at very high multiples of the predicted human efficacious Cmax. In addition, this study demonstrates the importance of assessing the safety significance of in-vitro selectivity findings with in-vivo mechanistic evaluation. doi:10.1016/j.vascn.2011.03.067
Poster No: 62 Rotarod performance as a functional biomarker of musculoskeletal syndrome for in vivo screening in LI/LO Suzanne Nodop Mazurek, Paul Harrison, Jun Li, Gerald Nabozny, Glenn Reinhardt, Ryan Fryer Boehringer Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, Ridgefield, CT, USA