RESUMEN
Fulvestrant is an FDA-approved drug with a dual mechanism of action (MOA), acting as a full antagonist and degrader of the estrogen receptor protein. A significant limitation of fulvestrant is the dosing regimen required for efficacy. Due to its high lipophilicity and poor pharmacokinetic profile, fulvestrant needs to be administered through intramuscular injections which leads to injection site soreness. This route of administration also limits the dose and target occupancy in patients. We envisioned a best-in-class molecule that would function with the same dual MOA as fulvestrant, but with improved physicochemical properties and would be orally bioavailable. Herein we report our progress toward that goal, resulting in a new lead GNE-502 which addressed some of the liabilities of our previously reported lead molecule GNE-149.
Asunto(s)
Antineoplásicos/farmacología , Antineoplásicos/farmacocinética , Neoplasias de la Mama/tratamiento farmacológico , Descubrimiento de Drogas , Receptores de Estrógenos/metabolismo , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Células MCF-7 , Ratones , Estructura Molecular , Conformación Proteica , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Breast cancer remains a leading cause of cancer death in women, representing a significant unmet medical need. Here, we disclose our discovery efforts culminating in a clinical candidate, 35 (GDC-9545 or giredestrant). 35 is an efficient and potent selective estrogen receptor degrader (SERD) and a full antagonist, which translates into better antiproliferation activity than known SERDs (1, 6, 7, and 9) across multiple cell lines. Fine-tuning the physiochemical properties enabled once daily oral dosing of 35 in preclinical species and humans. 35 exhibits low drug-drug interaction liability and demonstrates excellent in vitro and in vivo safety profiles. At low doses, 35 induces tumor regressions either as a single agent or in combination with a CDK4/6 inhibitor in an ESR1Y537S mutant PDX or a wild-type ERα tumor model. Currently, 35 is being evaluated in Phase III clinical trials.
Asunto(s)
Antineoplásicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Carbolinas/uso terapéutico , Antagonistas del Receptor de Estrógeno/uso terapéutico , Receptor alfa de Estrógeno/metabolismo , Animales , Antineoplásicos/química , Antineoplásicos/farmacocinética , Carbolinas/química , Carbolinas/farmacocinética , Perros , Antagonistas del Receptor de Estrógeno/química , Antagonistas del Receptor de Estrógeno/farmacocinética , Femenino , Humanos , Células MCF-7 , Macaca fascicularis , Ratones , Estructura Molecular , Ratas , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Estrogen receptor alpha (ERα) is a well-validated drug target for ER-positive (ER+) breast cancer. Fulvestrant is FDA-approved to treat ER+ breast cancer and works through two mechanisms-as a full antagonist and selective estrogen receptor degrader (SERD)-but lacks oral bioavailability. Thus, we envisioned a "best-in-class" molecule with the same dual mechanisms as fulvestrant, but with significant oral exposure. Through lead optimization, we discovered a tool molecule 12 (GNE-149) with improved degradation and antiproliferative activity in both MCF7 and T47D cells. To illustrate the binding mode and key interactions of this scaffold with ERα, we obtained a cocrystal structure of 6 that showed ionic interaction of azetidine with Asp351 residue. Importantly, 12 showed favorable metabolic stability and good oral exposure. 12 exhibited antagonist effect in the uterus and demonstrated robust dose-dependent efficacy in xenograft models.
RESUMEN
Phenolic groups are responsible for the high clearance and low oral bioavailability of the estrogen receptor alpha (ERα) clinical candidate GDC-0927. An exhaustive search for a backup molecule with improved pharmacokinetic (PK) properties identified several metabolically stable analogs, although in general at the expense of the desired potency and degradation efficiency. C-8 hydroxychromene 30 is the first example of a phenol-containing chromene that not only maintained excellent potency but also exhibited 10-fold higher oral exposure in rats. The improved in vivo clearance in rat was hypothesized to be the result of C-8 hydroxy group being sterically protected from glucuronide conjugation. The excellent potency underscores the possibility of replacing the presumed indispensable phenolic group at C-6 or C-7 of the chromene core. Co-crystal structures were obtained to highlight the change in key interactions and rationalize the retained potency.
Asunto(s)
Azetidinas/farmacología , Receptor alfa de Estrógeno/metabolismo , Flavonoides/farmacología , Administración Oral , Animales , Azetidinas/administración & dosificación , Azetidinas/metabolismo , Azetidinas/farmacocinética , Cristalografía por Rayos X , Descubrimiento de Drogas , Estabilidad de Medicamentos , Flavonoides/administración & dosificación , Flavonoides/metabolismo , Flavonoides/farmacocinética , Humanos , Células MCF-7 , Microsomas Hepáticos/metabolismo , Ratas , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Disruption of interleukin-13 (IL-13) signaling with large molecule antibody therapies has shown promise in diseases of allergic inflammation. Given that IL-13 recruits several members of the Janus Kinase family (JAK1, JAK2, and TYK2) to its receptor complex, JAK inhibition may offer an alternate small molecule approach to disrupting IL-13 signaling. Herein we demonstrate that JAK1 is likely the isoform most important to IL-13 signaling. Structure-based design was then used to improve the JAK1 potency of a series of previously reported JAK2 inhibitors. The ability to impede IL-13 signaling was thereby significantly improved, with the best compounds exhibiting single digit nM IC50's in cell-based assays dependent upon IL-13 signaling. Appropriate substitution was further found to influence inhibition of a key off-target, LRRK2. Finally, the most potent compounds were found to be metabolically labile, which makes them ideal scaffolds for further development as topical agents for IL-13 mediated diseases of the lungs and skin (for example asthma and atopic dermatitis, respectively).
Asunto(s)
Dermatitis Atópica/genética , Interleucina-13/metabolismo , Janus Quinasa 1/antagonistas & inhibidores , Janus Quinasa 2/antagonistas & inhibidores , Humanos , Transducción de SeñalRESUMEN
Preclinical and clinical evidence indicates that a subset of asthma is driven by type 2 cytokines such as interleukin-4 (IL-4), IL-5, IL-9, and IL-13. Additional evidence predicts pathogenic roles for IL-6 and type I and type II interferons. Because each of these cytokines depends on Janus kinase 1 (JAK1) for signal transduction, and because many of the asthma-related effects of these cytokines manifest in the lung, we hypothesized that lung-restricted JAK1 inhibition may confer therapeutic benefit. To test this idea, we synthesized iJak-381, an inhalable small molecule specifically designed for local JAK1 inhibition in the lung. In pharmacodynamic models, iJak-381 suppressed signal transducer and activator of transcription 6 activation by IL-13. Furthermore, iJak-381 suppressed ovalbumin-induced lung inflammation in both murine and guinea pig asthma models and improved allergen-induced airway hyperresponsiveness in mice. In a model driven by human allergens, iJak-381 had a more potent suppressive effect on neutrophil-driven inflammation compared to systemic corticosteroid administration. The inhibitor iJak-381 reduced lung pathology, without affecting systemic Jak1 activity in rodents. Our data show that local inhibition of Jak1 in the lung can suppress lung inflammation without systemic Jak inhibition in rodents, suggesting that this strategy might be effective for treating asthma.
Asunto(s)
Asma/tratamiento farmacológico , Asma/enzimología , Janus Quinasa 1/antagonistas & inhibidores , Pulmón/enzimología , Inhibidores de Proteínas Quinasas/uso terapéutico , Administración por Inhalación , Alérgenos , Animales , Asma/patología , Dexametasona/farmacología , Dexametasona/uso terapéutico , Modelos Animales de Enfermedad , Eosinófilos/efectos de los fármacos , Eosinófilos/metabolismo , Eosinófilos/patología , Cobayas , Inflamación/patología , Janus Quinasa 1/metabolismo , Pulmón/efectos de los fármacos , Pulmón/patología , Ovalbúmina , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacocinética , Transducción de Señal , Resultado del TratamientoRESUMEN
Herein we report identification of an imidazopyridine class of potent and selective TYK2 inhibitors, exemplified by prototype 6, through constraint of the rotatable amide bond connecting the pyridine and aryl rings of compound 1. Further optimization led to generation of compound 30 that potently inhibits the TYK2 enzyme and the IL-23 pathway in cells, exhibits selectivity against cellular JAK2 activity, and has good pharmacokinetic properties. In mice, compound 30 demonstrated dose-dependent reduction of IL-17 production in a PK/PD model as well as in an imiquimod-induced psoriasis model. In this efficacy model, the IL-17 decrease was accompanied by a reduction of ear thickness indicating the potential of TYK2 inhibition as a therapeutic approach for psoriasis patients.
Asunto(s)
Imidazoles/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Piridinas/farmacología , TYK2 Quinasa/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Humanos , Imidazoles/síntesis química , Imidazoles/química , Estructura Molecular , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Piridinas/síntesis química , Piridinas/química , Relación Estructura-Actividad , TYK2 Quinasa/metabolismoRESUMEN
Checkpoint kinase 1 (ChK1) plays a key role in the DNA damage response, facilitating cell-cycle arrest to provide sufficient time for lesion repair. This leads to the hypothesis that inhibition of ChK1 might enhance the effectiveness of DNA-damaging therapies in the treatment of cancer. Lead compound 1 (GNE-783), the prototype of the 1,7-diazacarbazole class of ChK1 inhibitors, was found to be a highly potent inhibitor of acetylcholine esterase (AChE) and unsuitable for development. A campaign of analogue synthesis established SAR delineating ChK1 and AChE activities and allowing identification of new leads with improved profiles. In silico docking using a model of AChE permitted rationalization of the observed SAR. Compounds 19 (GNE-900) and 30 (GNE-145) were identified as selective, orally bioavailable ChK1 inhibitors offering excellent in vitro potency with significantly reduced AChE activity. In combination with gemcitabine, these compounds demonstrate an in vivo pharmacodynamic effect and are efficacious in a mouse p53 mutant xenograft model.
Asunto(s)
Acetilcolinesterasa/metabolismo , Carbazoles/química , Carbazoles/farmacología , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Acetilcolinesterasa/química , Acetilcolinesterasa/farmacocinética , Acetilcolinesterasa/uso terapéutico , Animales , Compuestos Aza/química , Compuestos Aza/farmacocinética , Compuestos Aza/farmacología , Compuestos Aza/uso terapéutico , Línea Celular Tumoral , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacocinética , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/uso terapéutico , Cristalografía por Rayos X , Perros , Humanos , Ratones , Ratones Desnudos , Modelos Moleculares , Neoplasias/tratamiento farmacológico , Neoplasias/enzimología , Inhibidores de Proteínas Quinasas/farmacocinética , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Quinasas/química , RatasRESUMEN
Checkpoint kinase 1 (ChK1) is activated in response to DNA damage, acting to temporarily block cell cycle progression and allow for DNA repair. It is envisaged that inhibition of ChK1 will sensitize tumor cells to treatment with DNA-damaging therapies, and may enhance the therapeutic window. High throughput screening identified carboxylate-containing diarylpyrazines as a prominent hit series, but with limited biochemical potency and no cellular activity. Through a series of SAR investigations and X-ray crystallographic analysis the critical role of polar contacts with conserved waters in the kinase back pocket was established. Structure-based design, guided by in silico modeling, transformed the series to better satisfy these contacts and the novel 1,7-diazacarbazole class of inhibitors was discovered. Here we present the genesis of this novel series and the identification of GNE-783, a potent, selective and orally bioavailable inhibitor of ChK1.
Asunto(s)
Compuestos Aza/química , Carbazoles/química , Carbolinas/farmacología , Descubrimiento de Drogas , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/química , Administración Oral , Animales , Carbolinas/administración & dosificación , Carbolinas/síntesis química , Carbolinas/farmacocinética , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Cristalografía por Rayos X , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacología , Sinergismo Farmacológico , Humanos , Ratones , Conformación Proteica , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Ratas , Relación Estructura-Actividad , Distribución Tisular , GemcitabinaRESUMEN
Amalgamation of the structure-activity relationship of two series of GlyT1 inhibitors developed at Merck led to the discovery of a clinical candidate, compound 16 (DCCCyB), which demonstrated excellent in vivo occupancy of GlyT1 transporters in rhesus monkey as determined by displacement of a PET tracer ligand.
RESUMEN
A series of heterocyclic sulfonamides have been developed which are potent and selective inhibitors of hGlyT1. SAR studies to optimise the in vitro and in vivo properties are described. Optimisation of the central scaffold resulted in cyclohexane sulfones 28 and 29, which have good PK properties and show promise for further development.
Asunto(s)
Proteínas de Transporte de Glicina en la Membrana Plasmática/antagonistas & inhibidores , Sulfonamidas/administración & dosificación , Sulfonamidas/química , Administración Oral , Animales , Disponibilidad Biológica , Proteínas de Transporte de Glicina en la Membrana Plasmática/metabolismo , Humanos , Masculino , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-Dawley , Sulfonamidas/metabolismo , Triazoles/administración & dosificación , Triazoles/síntesis químicaRESUMEN
Non-selective benzodiazepines, such as diazepam, interact with equivalent affinity and agonist efficacy at GABA(A) receptors containing either an alpha1, alpha2, alpha3 or alpha5 subunit. However, which of these particular subtypes are responsible for the anticonvulsant effects of diazepam remains uncertain. In the present study, we examined the ability of diazepam to reduce pentylenetetrazoLe (PTZ)-induced and maximal electroshock (MES)-induced seizures in mice containing point mutations in single (alpha1H101R, alpha2H101R or alpha5H105R) or multiple (alpha125H-->R) alpha subunits that render the resulting GABA(A) receptors diazepam-insensitive. Furthermore, the anticonvulsant properties of diazepam, the alpha1- and alpha3-selective compounds zolpidem and TP003, respectively, and the alpha2/alpha3 preferring compound TP13 were studied against PTZ-induced seizures. In the transgenic mice, no single subtype was responsible for the anticonvulsant effects of diazepam in either the PTZ or MES assay and neither the alpha3 nor alpha5 subtypes appeared to confer anticonvulsant activity. Moreover, whereas the alpha1 and alpha2 subtypes played a modest role with respect to the PTZ assay, they had a negligible role in the MES assay. With respect to subtype-selective compounds, zolpidem and TP003 had much reduced anticonvulsant efficacy relative to diazepam in both the PTZ and MES assays whereas TP13 had high anticonvulsant efficacy in the PTZ but not the MES assay. Taken together, these data not only indicate a role for alpha2-containing GABA(A) receptors in mediating PTZ and MES anticonvulsant activity but also suggest that efficacy at more than one subtype is required and that these subtypes act synergistically.
Asunto(s)
Anticonvulsivantes/farmacología , Benzodiazepinas/farmacología , Receptores de GABA-A/fisiología , Convulsiones/prevención & control , Animales , Sitios de Unión , Convulsivantes , Diazepam/farmacología , Electrochoque , Agonistas de Receptores de GABA-A , Ligandos , Ratones , Ratones Mutantes , Ratones Transgénicos , Pentilenotetrazol , Mutación Puntual , Subunidades de Proteína/agonistas , Subunidades de Proteína/genética , Subunidades de Proteína/fisiología , Piridinas/farmacología , Receptores de GABA-A/genética , Convulsiones/etiología , ZolpidemRESUMEN
The identification of a series of imidazo[1,2-b][1,2,4]triazines with high affinity and functional selectivity for the GABA(A) alpha3-containing receptor subtype is described, leading to the identification of a clinical candidate, 11. Compound 11 shows good bioavailability and half-life in preclinical species, and it is a nonsedating anxiolytic in both rat and squirrel monkey behavioral models.
Asunto(s)
Ansiolíticos/síntesis química , Agonistas de Receptores de GABA-A , Imidazoles/síntesis química , Triazinas/síntesis química , Animales , Ansiolíticos/química , Ansiolíticos/farmacología , Disponibilidad Biológica , Semivida , Humanos , Imidazoles/química , Imidazoles/farmacología , Técnicas de Placa-Clamp , Ensayo de Unión Radioligante , Ratas , Receptores de GABA-A/fisiología , Saimiri , Relación Estructura-Actividad , Triazinas/química , Triazinas/farmacologíaRESUMEN
Imidazo[1,2-a]pyrimidines are GABA(A) receptor benzodiazepine binding site ligands which can exhibit functional selectivity for the alpha(3) subtype over the alpha(1) subtype. SAR studies to optimize this functional selectivity are described.
Asunto(s)
Imidazoles/química , Imidazoles/metabolismo , Pirimidinas/química , Pirimidinas/metabolismo , Receptores de GABA-A/metabolismo , Ligandos , Estructura Molecular , Pirimidinas/síntesis química , Sensibilidad y Especificidad , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
8-Fluoroimidazo[1,2-a]pyridine has been established as a physicochemical mimic of imidazo[1,2-a]pyrimidine, using both in silico and traditional techniques. Furthermore, a novel synthesis of a 3,7-disubstituted-8-fluoroimidazopyridine 3 has been developed and the utility of the physicochemical mimicry has been demonstrated in an in vitro system. Here, the 8-fluoroimidazopyridine ring contained in ligand 3 acts as a bioisosteric replacement for imidazopyrimidine in the GABA(A) receptor modulator 2.
Asunto(s)
Regulación Alostérica/efectos de los fármacos , Agonistas del GABA/síntesis química , Agonistas de Receptores de GABA-A , Imidazoles/síntesis química , Piridinas/síntesis química , Animales , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Agonistas del GABA/química , Agonistas del GABA/farmacología , Humanos , Imidazoles/química , Imidazoles/farmacología , Ligandos , Ratones , Estructura Molecular , Piridinas/química , Piridinas/farmacología , Proteínas Recombinantes/agonistas , Relación Estructura-ActividadRESUMEN
A series of high-affinity GABA(A) agonists with good oral bioavailability in rat and dog and functional selectivity for the GABA(A)alpha2 and -alpha3 subtypes is reported. The 7-trifluoromethylimidazopyrimidine 14g and the 7-propan-2-olimidazopyrimidine 14k are anxiolytic in both conditioned and unconditioned animal models of anxiety with minimal sedation observed at full BZ binding site occupancy.
Asunto(s)
Trastornos de Ansiedad/tratamiento farmacológico , Agonistas de Receptores de GABA-A , Pirimidinas/farmacología , Administración Oral , Animales , Sitios de Unión , Disponibilidad Biológica , Línea Celular , Modelos Animales de Enfermedad , Perros , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Estructura Molecular , Técnicas de Placa-Clamp , Pirimidinas/síntesis química , Pirimidinas/farmacocinética , Ratas , Receptores de GABA-A , Relación Estructura-ActividadRESUMEN
The cyclopyrrolone pagoclone binds with roughly equivalent high affinity (0.7-9.1nM) to the benzodiazepine binding site of human recombinant GABA(A) receptors containing either an alpha1, alpha2, alpha3 or alpha5 subunit. However, whereas it was a partial agonist at alpha1-, alpha2- and alpha5-containing GABA(A) receptors, pagoclone was a full agonist at receptors containing an alpha3 subunit. In the rat elevated plus maze assay pagoclone (3mg/kg) had significant anxiolytic-like activity but at all three doses tested (0.3, 1 and 3mg/kg p.o.) it produced a significant reduction in the total distance travelled. This sedative-like effect was confirmed in rat chain-pulling and spontaneous locomotor assays. Surprisingly, in the plasma and brain samples derived from the elevated plus maze assay, the major metabolite of pagoclone, 5'-hydroxy pagoclone, was present at 10-20-fold higher concentrations relative to the parent compound. In order to establish whether this metabolite might have pharmacological activity, we measured its affinity and efficacy profile and found that both were comparable to those of pagoclone with the exception that efficacy at the alpha1 subtype was considerably greater for 5'-hydroxy pagoclone compared with the parent. This metabolite had significant anxiolytic-like activity in the elevated plus maze but at these same doses (0.3-3mg/kg p.o.) also produced sedation. It is therefore likely that in rats 5'-hydroxy pagoclone mediates the majority of the pharmacological actions following pagoclone administration.
Asunto(s)
Conducta Animal/efectos de los fármacos , Naftiridinas/farmacología , Animales , Sitios de Unión/efectos de los fármacos , Encéfalo/metabolismo , Línea Celular , Relación Dosis-Respuesta a Droga , Fibroblastos , Flumazenil/farmacología , Moduladores del GABA/farmacología , Humanos , Indoles/farmacocinética , Isoindoles , Isomerismo , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Actividad Motora/efectos de los fármacos , Naftiridinas/sangre , Naftiridinas/química , Naftiridinas/farmacocinética , Subunidades de Proteína/metabolismo , Desempeño Psicomotor/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de GABA-A/química , Receptores de GABA-A/efectos de los fármacos , Factores de Tiempo , Tritio/farmacocinéticaRESUMEN
Imidazo[1,2-a]pyrazin-8-ones, imidazo[1,2-d][1,2,4]triazin-8-ones and imidazo[2,1-f][1,2,4]triazin-8-ones are high affinity GABA(A) agonists. Compound 16d has good oral bioavailability in rat, functional selectivity for the GABA(A)alpha2 and alpha3-subtypes and is anxiolytic in a conditioned animal model of anxiety with minimal sedation observed at full BZ binding site occupancy.
Asunto(s)
Ansiolíticos/farmacología , Trastornos de Ansiedad/tratamiento farmacológico , Agonistas del GABA/farmacología , Agonistas de Receptores de GABA-A , Administración Oral , Animales , Ansiolíticos/síntesis química , Benzodiazepinas/metabolismo , Sitios de Unión , Disponibilidad Biológica , Línea Celular , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Agonistas del GABA/síntesis química , Humanos , Ratones , Estructura Molecular , Técnicas de Placa-Clamp , Ratas , Receptores de GABA-A , Proteínas Recombinantes/agonistas , Relación Estructura-ActividadRESUMEN
The GABA(A) receptor subtypes responsible for the anxiolytic effects of nonselective benzodiazepines (BZs) such as chlordiazepoxide (CDP) and diazepam remain controversial. Hence, molecular genetic data suggest that alpha2-rather than alpha3-containing GABA(A) receptors are responsible for the anxiolytic effects of diazepam, whereas the anxiogenic effects of an alpha3-selective inverse agonist suggest that an agonist selective for this subtype should be anxiolytic. We have extended this latter pharmacological approach to identify a compound, 4,2'-difluoro-5'-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-á]pyridin-3-yl]biphenyl-2-carbonitrile (TP003), that is an alpha3 subtype selective agonist that produced a robust anxiolytic-like effect in both rodent and non-human primate behavioral models of anxiety. Moreover, in mice containing a point mutation that renders alpha2-containing receptors BZ insensitive (alpha2H101R mice), TP003 as well as the nonselective agonist CDP retained efficacy in a stress-induced hyperthermia model. Together, these data show that potentiation of alpha3-containing GABA(A) receptors is sufficient to produce the anxiolytic effects of BZs and that alpha2 potentiation may not be necessary.