Ulotaront: A TAAR1 Agonist for the Treatment of Schizophrenia

Ulotaront (SEP-363856) is a trace-amine associated receptor 1 (TAAR1) agonist with 5-HT1A receptor agonist activity in Phase 3 clinical development, with FDA Breakthrough Therapy Designation, for the treatment of schizophrenia. TAAR1 is a G-protein-coupled receptor (GPCR) that is expressed in cortical, limbic, and midbrain monoaminergic regions. It is activated by endogenous trace amines, and is believed to play an important role in modulating dopaminergic, serotonergic, and glutamatergic circuitry. TAAR1 agonism data are reported herein for ulotaront and its analogues in comparison to endogenous TAAR1 agonists. In addition, a human TAAR1 homology model was built around ulotaront to identify key interactions and attempt to better understand the scaffold-specific TAAR1 agonism structure–activity relationships.

CoREST Complex-Selective Histone Deacetylase Inhibitors Show Prosynaptic Effects and an Improved Safety Profile To Enable Treatment of Synaptopathies

Synaptic dysfunction is a pathological feature in many neurodegenerative disorders, including Alzheimer’s disease, and synaptic loss correlates closely with cognitive decline. Histone deacetylases (HDACs) are involved in chromatin remodeling and gene expression and have been shown to regulate synaptogenesis and synaptic plasticity, thus providing an attractive drug discovery target for promoting synaptic growth and function. To date, HDAC inhibitor compounds with prosynaptic effects are plagued by known HDAC dose-limiting hematological toxicities, precluding their application to treating chronic neurologic conditions. We have identified a series of novel HDAC inhibitor compounds that selectively inhibit the HDAC–co-repressor of repressor element-1 silencing transcription factor (CoREST) complex while minimizing hematological side effects. HDAC1 and HDAC2 associate with multiple co-repressor complexes including CoREST, which regulates neuronal gene expression. We show that selectively targeting the CoREST co-repressor complex with the representative compound Rodin-A results in increased spine density and synaptic proteins, and improved long-term potentiation in a mouse model at doses that provide a substantial safety margin that would enable chronic treatment. The CoREST-selective HDAC inhibitor Rodin-A thus represents a promising therapeutic strategy in targeting synaptic pathology involved in neurologic disorders.

Diving into the Water: Inducible Binding Conformations for BRD4, TAF1(2), BRD9, and CECR2 Bromodomains

The biological role played by non-BET bromodomains remains poorly understood, and it is therefore imperative to identify potent and highly selective inhibitors to effectively explore the biology of individual bromodomain proteins. A ligand-efficient nonselective bromodomain inhibitor was identified from a 6-methyl pyrrolopyridone fragment. Small hydrophobic substituents replacing the N-methyl group were designed directing toward the conserved bromodomain water pocket, and two distinct binding conformations were then observed. The substituents either directly displaced and rearranged the conserved solvent network, as in BRD4(1) and TAF1(2), or induced a narrow hydrophobic channel adjacent to the lipophilic shelf, as in BRD9 and CECR2. The preference of distinct substituents for individual bromodomains provided selectivity handles useful for future lead optimization efforts for selective BRD9, CECR2, and TAF1(2) inhibitors.

Fragment-Based Discovery of a Selective and Cell-Active Benzodiazepinone CBP/EP300 Bromodomain Inhibitor (CPI-637)

CBP and EP300 are highly homologous, bromodomain-containing transcription coactivators involved in numerous cellular pathways relevant to oncology. As part of our effort to explore the potential therapeutic implications of selectively targeting bromodomains, we set out to identify a CBP/EP300 bromodomain inhibitor that was potent both in vitro and in cellular target engagement assays and was selective over the other members of the bromodomain family. Reported here is a series of cell-potent and selective probes of the CBP/EP300 bromodomains, derived from the fragment screening hit 4-methyl-1,3,4,5-tetrahydro-2H-benzo[b][1,4]diazepin-2-one.

Discovery of Benzotriazolo[4,3-d][1,4]diazepines as Orally Active Inhibitors of BET Bromodomains

Inhibition of the bromodomains of the BET family, of which BRD4 is a member, has been shown to decrease myc and interleukin (IL) 6 in vivo, markers that are of therapeutic relevance to cancer and inflammatory disease, respectively. Herein we report substituted benzo[b]isoxazolo[4,5-d]azepines and benzotriazolo[4,3-d][1,4]diazepines as fragment-derived novel inhibitors of the bromodomain of BRD4. Compounds from these series were potent and selective in cells, and subsequent optimization of microsomal stability yielded representatives that demonstrated dose- and time-dependent reduction of plasma IL-6 in mice.

Abstract A20: A leukemic model of acquired resistance to BET inhibition reveals a role for CBP/EP300 bromodomains in the regulation of c-MYC expression

Pharmacological modulation of c-MYC expression has recently become possible through small molecule engagement of the BET bromodomain proteins. As multiple BET inhibitors (BETi) progress through clinical trials, understanding possible mechanisms of acquired resistance becomes imperative to maximize therapeutic efficacy, assess possible drug combination strategies, and identify characteristics of next generation BET inhibitors. In the present study, we describe a cellular model of BETi resistance, which demonstrates a significantly blunted phenotypic and molecular response to BETi. The expression of c-MYC mRNA, highly susceptible to BETi in the parental cells, is restored in resistant cells through transcriptional bypass of BET-mediated co-activation. Through the use of a novel CBP/EP300 bromodomain inhibitor (CBP/EP300i), we show that c-MYC expression in BETi-resistant cells is dependent on CBP/EP300 bromodomain function, and that co-treatment with CBP/EP300i restores phenotypic sensitivity. CBP/EP300i was additionally found to transcriptionally silence MYC expression in numerous myeloma and leukemia derived cell lines in a manner comparable to BETi, identifying a novel modality to pharmacologically target the MYC oncogenic axis. While both BET and CBP/EP300 bromodomains regulate the expression of MYC, their transcriptional and phenotypic effects are otherwise distinct, suggesting that CBP/EP300 bromodomain inhibition may represent an alternative or complementary therapeutic option to BET bromodomain inhibition.

Citation Format: Andrew R. Conery, Richard C. Centore, Charlie Hatton, Adrianne Neiss, Hon-Ren Huang, Patricia J. Keller, Alexander M. Taylor, Alexandre Cote, Michael C. Hewitt, Christopher G. Nasveschuk, Yves Leblanc, Shihua Yao, Eneida Pardo, Laura Zawadzke, Florence Poy, Hari Jayaram, Shivangi Joshi, Peter Sandy, Anthony Romero, Terry Crawford, Richard Pastor, Tommy Lai, Kevin Chen, Jian Wang, Steven Magnuson, Brian K. Albrecht, Steve Bellon, Barbara M. Bryant, Robert J. Sims, III. A leukemic model of acquired resistance to BET inhibition reveals a role for CBP/EP300 bromodomains in the regulation of c-MYC expression. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A20.

Pharmacological evaluation of a novel phosphodiesterase 10A inhibitor in models of antipsychotic activity and cognition

In this study, we report the pharmacological effects of a novel PDE10A inhibitor, SEP-39. SEP-39 is a potent (1.0nM) inhibitor of human PDE10A in vitro, with good selectivity (>16000-fold) against other PDEs. In an in vivo occupancy study, the RO50 value was determined to be 0.7mg/kg (p.o.), corresponding to plasma and brain exposures of 28ng/mL and 43ng/g, respectively. Using microdialysis, we show that 3mg/kg (p.o.) SEP-39 significantly increased rat striatal cGMP concentrations. Furthermore, SEP-39 inhibits PCP-induced hyperlocomotion at doses of 1 and 3mg/kg (p.o.) corresponding to 59-86% occupancy. At similar doses in a catalepsy study, the time on the bar was increased but the maximal effect was less than that seen with haloperidol. In an EEG study, 3 and 10mg/kg (p.o.) SEP-39 suppressed REM intensity and increased the latency to REM sleep. We also demonstrate the procognitive effects of SEP-39 in the rat novel object recognition assay. These effects appear to require less PDE10A inhibition than the reversal of PCP-induced hyperlocomotion or EEG effects, as improvements in recognition index were seen at doses of 0.3mg/kg and above. Our data demonstrate that SEP-39 is a potent, orally active PDE10A inhibitor with therapeutic potential in a number of psychiatric indications.

Development of methyl isoxazoleazepines as inhibitors of BET

In this report we detail the evolution of our previously reported thiophene isoxazole BET inhibitor chemotype exemplified by CPI-3 to a novel bromodomain selective chemotype (the methyl isoxazoleazepine chemotype) exemplified by carboxamide 23. The methyl isoxazoleazepine chemotype provides potent inhibition of the bromodomains of the BET family, excellent in vivo PK across species, low unbound clearance, and target engagement in a MYC PK-PD model.

A practical synthesis of indoles via a Pd-catalyzed C-N ring formation

A method for the synthesis of N-functionalized C2-/C3-substituted indoles via Pd-catalyzed C-N bond coupling of halo-aryl enamines is described. The general strategy utilizes a variety of amines and β-keto esters which are elaborated into halo-aryl enamines as latent precursors to indoles. The preferred conditions comprising the RuPhos precatalyst and RuPhos in the presence of NaOMe in 1,4-dioxane tolerate a variety of substituents and are scalable for the construction of indoles in multigram quantities.

Discovery, Design, and Optimization of Isoxazole Azepine BET Inhibitors

The identification of a novel series of small molecule BET inhibitors is described. Using crystallographic binding modes of an amino-isoxazole fragment and known BET inhibitors, a structure-based drug design effort lead to a novel isoxazole azepine scaffold. This scaffold showed good potency in biochemical and cellular assays and oral activity in an in vivo model of BET inhibition.

Synthesis and pharmacological characterization of bicyclic triple reuptake inhibitor 3-aryl octahydrocyclopenta[c]pyrrole analogues

The present work expands the chemical space known to offer potent inhibition of the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) and discloses novel bicyclic octahydrocyclopenta[c]pyrrole and octahydro-1H-isoindole scaffolds as potent triple reuptake inhibitors (TRIs) for the potential treatment of depression. Optimized compounds 22a (SERT, NET, DAT, IC(50) = 20, 109, 430 nM), 23a (SERT, NET, DAT, IC(50) = 29, 85, 168 nM), and 26a (SERT, NET, DAT, IC(50) = 53, 150, 140 nM) were highly brain penetrant, active in vivo in the mouse tail suspension test at 10 and 30 mpk PO, and were not generally motor stimulants at doses ranging from 1 to 30 mpk PO. Moderate in vitro cytochrome P450 (CYP) and potassium ion channel Kv11.1 (hERG) inhibition were uncovered as potential liabilities for the chemical series.

Discovery of N-methyl-1-(1-phenylcyclohexyl)ethanamine, a novel triple serotonin, norepinephrine and dopamine reuptake inhibitor

Novel chiral cyclohexylaryl amines were developed with potent reuptake inhibition against the serotonin, norepinephrine and dopamine transporters and activity at 10 and 30 mpk PO in the mouse tail suspension test. Prototype compound 31 (SERT, NET, DAT IC(50) ≤ 1, 21, 28 nM) was highly brain penetrant, had minimal CYP and hERG inhibition, and represents a previously undisclosed architecture with potential for treatment of major depressive disorder.

Discovery of 1-(3,4-dichlorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydroquinolin-4-amine, a dual serotonin and dopamine reuptake inhibitor

The present work describes a series of novel tetrahydroquinoline amines that potently inhibit the in vitro reuptake of serotonin and dopamine (dual reuptake inhibitors). The compounds are structurally related to a series we disclosed previously, but are improved with respect to cytochrome P-450 enzyme (CYP) and potassium ion channel Kv11.1 (hERG) inhibition and synthetic accessibility. The detailed synthesis and in vitro activity and ADME profile of the compounds is described, which represent a previously undisclosed dual reuptake inhibitor chemotype.

Derivatives of tramadol for increased duration of effect

Tramadol is a centrally acting opioid analgesic structurally related to codeine and morphine. Analogs of tramadol with deuterium-for-hydrogen replacement at metabolically active sites were prepared and evaluated in vitro and in vivo.

Rapid synthesis of a glycosylphosphatidylinositol-based malaria vaccine using automated solid-phase oligosaccharide synthesis

Described is an automated synthesis of hexasaccharide malarial toxin 1, currently under development as a malaria vaccine candidate. Using a combination of automated solid-phase methods and solution-phase fragment coupling, the target glycosylphosphatidylinositol was assembled in a matter of days, compared with several weeks for a comparable solution-phase synthesis.

Epidemiology and predictive values of risk factors for neonatal group B streptococcal sepsis

OBJECTIVES

To determine the incidence of and factors affecting risk factors for neonatal group B streptococcal (GBS) sepsis and their predictive values for intrapartum GBS carriage; to calculate the proportions of women eligible for intrapartum antibiotic prophylaxis (IAP) using different selection protocols.

DESIGN

Cohort study.

SETTING

Antenatal clinics and labour wards of a community hospital and a tertiary referral centre in western Sydney

POPULATION

Women attending antenatal clinics during the study periods were invited to participate.

METHODS

Approximately 500 women attending antenatal clinics were screened for GBS carriage at 26-32 weeks gestation and at delivery, using several screening methods. Clinical risk factors for neonatal sepsis were recorded during labour.

MAIN OUTCOME MEASURES

Incidence of antenatal anovaginal GBS carriage and clinical risk factors during labour, their predictive values for intra-partum GBS carriage and their relationship, if any, to demographic and obstetric factors.

RESULTS

Antenatal and intra-partum GBS carriage rates were similar but varied from 18% to 27%, depending on screening methods. The best positive and negative predictive values of antenatal GBS culture, for intra-partum carriage, were 69% (95% confidence interval (CI) 64-74) and 92% (95% CI 50-94) respectively Clinical risk factors occurred in similar proportions of GBS carriers and non-carriers.

CONCLUSIONS

Neither early antenatal screening nor clinical risk factors are reliable predictors of intra-partum GBS carriage. Intra-partum antibiotic prophylaxis based on GBS carriage or risk factors when carrier status is unknown would involve approximately 35% of women, compared with approximately 16% if based on risk factors only Both strategies would prevent similar proportions of neonatal deaths from GBS sepsis. Compliance with a preventive protocol is the most likely determinant of its overall effectiveness.

Synthetic GPI as a candidate anti-toxic vaccine in a model of malaria

The malaria parasite Plasmodium falciparum infects 5-10% of the world's population and kills two million people annually. Fatalities are thought to result in part from pathological reactions initiated by a malarial toxin. Glycosylphosphatidylinositol (GPI) originating from the parasite has the properties predicted of a toxin; however, a requirement for toxins in general and GPI in particular in malarial pathogenesis and fatality remains unproven. As anti-toxic vaccines can be highly effective public health tools, we sought to determine whether anti-GPI vaccination could prevent pathology and fatalities in the Plasmodium berghei/rodent model of severe malaria. The P. falciparum GPI glycan of the sequence NH(2)-CH(2)-CH(2)-PO(4)-(Man alpha 1-2)6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcNH(2)alpha 1-6myo-inositol-1,2-cyclic-phosphate was chemically synthesized, conjugated to carriers, and used to immunize mice. Recipients were substantially protected against malarial acidosis, pulmonary oedema, cerebral syndrome and fatality. Anti-GPI antibodies neutralized pro-inflammatory activity by P. falciparum in vitro. Thus, we show that GPI is a significant pro-inflammatory endotoxin of parasitic origin, and that several disease parameters in malarious mice are toxin-dependent. GPI may contribute to pathogenesis and fatalities in humans. Synthetic GPI is therefore a prototype carbohydrate anti-toxic vaccine against malaria.

Automated solid-phase synthesis of a branched Leishmania cap tetrasaccharide

[reaction--see text] Described is the first automated solid-phase synthesis of a branched oligosaccharide by stepwise assembly from monosaccharides. Cap tetrasaccharide 1, found as part of the cell surface lipophosphoglycan (LPG) of the protozoan parasite Leishmania, was readily prepared using glycosyl phosphate and glycosyl trichloroacetimidate building blocks.

Solution and solid-support synthesis of a potential leishmaniasis carbohydrate vaccine

The synthesis of a potential carbohydrate vaccine for the parasitic disease leishmaniasis is described. New solution- and solid-phase synthetic strategies were explored for the assembly of a unique tetrasaccharide antigen found on the Leishmania lipophosphoglycan. An initial solution-phase synthesis relied on thioglycosides as building blocks and the establishment of the central disaccharide from lactal via an oxidation-reduction sequence. A second approach was completed both in solution and on solid support. The solid-phase synthesis relied on assembly from monosaccharide units and was used to evaluate different glycosylating agents in the efficient installation of the galactose beta-(1-->4) mannoside. Glycosyl phosphates proved most successful in this endeavor. This first solid-phase synthesis of the Leishmania cap provided rapid access to the tetrasaccharide in 18% overall yield while requiring only a single purification step. The synthetic cap tetrasaccharide was conjugated to the immunostimulator Pam3Cys to create fully synthetic carbohydrate vaccine 1 and to the carrier protein KLH to form semisynthetic vaccine 2. Currently, both constructs have entered initial immunological experiments in mice targeted at the development of a vaccine against the parasitic disease leishmaniasis.

Invasive Haemophilus influenzae type b disease in elderly nursing home residents: two related cases

We investigated two fatal cases of invasive Haemophilus influenzae type b (Hib) infection in a community nursing home in western Sydney, Australia. Two elderly women had lived in the same room, and the onset of their illness was 5 days apart. Hib isolates from blood cultures showed identical profiles by pulsed field gel electrophoresis. These findings suggest that Hib infection was transmitted within this nursing home. Serious Hib disease may be underrecognized in this setting. Continued surveillance and serotyping of invasive H. influenzae disease is essential for identifying groups at increasing risk that may benefit from immunization against Hib.