Publications by authors named "Namchuk M"

Drug discovery and development has experienced an incredible paradigm shift in the past two decades. What once was considered a predominant R&D landscape of small molecules within a prescribed properties and mechanism space now includes an innovative wave of new chemical modalities. Scientists in the pharmaceutical industry can now strategize across a variety of modalities to find the best option to modulate a given target and provide treatment for a specific disease.

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Introduction: The atypical antipsychotic olanzapine is approved for the treatment of schizophrenia and bipolar I disorder; however, weight gain and metabolic dysregulation associated with olanzapine therapy have limited its clinical utility. In clinical studies, treatment with the combination of olanzapine and the opioid receptor antagonist samidorphan (OLZ/SAM) mitigated olanzapine-associated weight gain while providing antipsychotic efficacy similar to that of olanzapine. Although samidorphan is structurally similar to the opioid receptor antagonist naltrexone, the two differ in their pharmacokinetics and in vitro binding affinities to mu, delta, and kappa opioid receptors (MOR, DOR, and KOR, respectively).

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Pharmacologically active compounds with known biological targets were evaluated for inhibition of SARS-CoV-2 infection in cell and tissue models to help identify potent classes of active small molecules and to better understand host-virus interactions. We evaluated 6,710 clinical and preclinical compounds targeting 2,183 host proteins by immunocytofluorescence-based screening to identify SARS-CoV-2 infection inhibitors. Computationally integrating relationships between small molecule structure, dose-response antiviral activity, host target, and cell interactome produced cellular networks important for infection.

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Emergency Use Authorization (EUA) allows the US Food and Drug Administration (FDA) to expedite the availability of therapeutics in the context of a public health emergency. To date, an evidentiary standard for clinical efficacy to support an EUA has not yet been established. This review examines the clinical data submitted in support of EUA for antiviral and anti-inflammatory therapeutics for coronavirus disease 2019 (COVID-19) through December of 2021 and the resilience of the authorization as new clinical data arose subsequent to the authorization.

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A combination of olanzapine and samidorphan (OLZ/SAM) received US Food and Drug Administration approval in May 2021 for the treatment of adults with schizophrenia or bipolar I disorder. OLZ/SAM provides the efficacy of olanzapine, while mitigating olanzapine-associated weight gain. This exploratory study characterized the metabolic profile of OLZ/SAM in healthy volunteers to gain mechanistic insights.

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The main protease (M) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease (COVID-19), is an ideal target for pharmaceutical inhibition. M is conserved among coronaviruses and distinct from human proteases. Viral replication depends on the cleavage of the viral polyprotein at multiple sites.

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Identification of host factors contributing to replication of viruses and resulting disease progression remains a promising approach for development of new therapeutics. Here, we evaluated 6710 clinical and preclinical compounds targeting 2183 host proteins by immunocytofluorescence-based screening to identify SARS-CoV-2 infection inhibitors. Computationally integrating relationships between small molecule structure, dose-response antiviral activity, host target and cell interactome networking produced cellular networks important for infection.

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Article Synopsis
  • - The global effort to fight the SARS-CoV-2 pandemic has led to some promising preventive measures, but there's still a need for affordable and effective treatments.
  • - Researchers are using a new high-capacity screening method called VirtualFlow to find inhibitors that can target SARS-CoV-2 effectively.
  • - This innovative approach involved searching nearly 1 billion molecules against 40 different target sites related to the virus and its host, including both viral enzymes and important protein interactions.
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The COVID-19 pandemic has generated an unprecedented response within the scientific community. Extraordinary efforts have been undertaken to identify potential new therapeutics to treat SARS-CoV-2 infection spanning traditional medicinal chemistry, repurposing, and computational approaches. The breadth of the effort and rapid progression of many small molecules to clinical testing provide an opportunity to determine what chemical and testing approaches have been the most efficient in identifying potential treatments and how this may inform preparation for future pandemics.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), previously known as 2019 novel coronavirus (2019-nCoV), has spread rapidly across the globe, creating an unparalleled global health burden and spurring a deepening economic crisis. As of July 7th, 2020, almost seven months into the outbreak, there are no approved vaccines and few treatments available. Developing drugs that target multiple points in the viral life cycle could serve as a strategy to tackle the current as well as future coronavirus pandemics.

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Serious concerns about the way research is organized collectively are increasingly being raised. They include the escalating costs of research and lower research productivity, low public trust in researchers to report the truth, lack of diversity, poor community engagement, ethical concerns over research practices, and irreproducibility. Open science (OS) collaborations comprise of a set of practices including open access publication, open data sharing and the absence of restrictive intellectual property rights with which institutions, firms, governments and communities are experimenting in order to overcome these concerns.

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Background: Olanzapine, regarded as one of the most efficacious antipsychotic medications for the treatment of schizophrenia, is associated with a high risk of weight gain and metabolic dysfunction. ALKS 3831, a clinical candidate for treatment of schizophrenia, is a combination of olanzapine and samidorphan, an opioid receptor antagonist. The addition of samidorphan is intended to mitigate weight gain and the metabolic dysregulation associated with the use of olanzapine.

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A combination of buprenorphine (BUP) and samidorphan (SAM) at a 1:1 (mg/mg) fixed-ratio dose is being investigated as an adjunctive treatment of major depressive disorder (BUP/SAM, ALKS 5461). Both [H]BUP and [H]SAM bound to the -, -, and -opioid receptors (MOR, KOR, and DOR, respectively) with K values of 3 nM or less. [H]BUP dissociated from the MOR more slowly than [H]SAM did.

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Aberrant activation of signaling through the RAS-RAF-MEK-ERK (MAPK) pathway is implicated in numerous cancers, making it an attractive therapeutic target. Although BRAF and MEK-targeted combination therapy has demonstrated significant benefit beyond single-agent options, the majority of patients develop resistance and disease progression after approximately 12 months. Reactivation of ERK signaling is a common driver of resistance in this setting.

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Purpose Of Review: Treatment of chronic disease in a manner that promotes compliance and patient adherence has necessitated the consideration for drug delivery approaches that reduce the burden of regimens requiring daily treatment. Long-acting injectable (LAI) products have been developed in many disease areas and are now being exploited for the treatment of infectious disease, most notably HIV.

Recent Findings: Research published over the past 3 years has shown that LAI nanosuspensions of nonnucleoside reverse transcriptase inhibitors and integrase inhibitors provide extended exposure to the active drug over a period of days to weeks.

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While several therapeutic options exist, the need for more effective, safe, and convenient treatment for a variety of autoimmune diseases persists. Targeting the Janus tyrosine kinases (JAKs), which play essential roles in cell signaling responses and can contribute to aberrant immune function associated with disease, has emerged as a novel and attractive approach for the development of new autoimmune disease therapies. We screened our compound library against JAK3, a key signaling kinase in immune cells, and identified multiple scaffolds showing good inhibitory activity for this kinase.

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The discovery of potent thienoimidazole-based HCV NS5A inhibitors is herein reported. A novel method to access the thienoimidazole [5,5]-bicyclic system is disclosed. This method gave access to a common key intermediate (6) that was engaged in Suzuki or Sonogashira reactions with coupling partners bearing different linkers.

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In acute myelogenous leukemia (AML), the FLT3 receptor tyrosine kinase (RTK) is highly expressed with 30% of patients expressing a mutated, constitutively active form of this protein. To inhibit this receptor, VX-322 was developed and found to be very potent against both the FLT3 and c-KIT RTKs with enzyme K(i) values of <1 nM and a cellular IC(50) between 1 and 5 nM. It was efficacious in a FLT3-ITD dependent myeloproliferative mouse model, doubling survival compared to other FLT3 inhibitors, with 25% of the mice cured.

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A high-throughput screen of our compound archive revealed a novel class of dual FMS-like tyrosine kinase 3 (FLT3)/c-KIT inhibitors. With the help of molecular modeling, this class was rapidly optimized for both potency against FLT3 and FLT3/c-KIT and excellent potency in cell-based assays, leading to dose-dependent cell death in acute myelogenous leukemia (AML) patient blast samples. Ultimately, the AML patient blast data defined the preferred target profile as we designed and evaluated a set of FLT3 selective and FLT3/c-KIT dual molecules.

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The synthesis and characterization of a novel polycyclic azaindole based derivative is disclosed, and its binding to JAK2 is described. The compound is further evaluated for its ability to block the EPO/JAK2 signaling cascade in vitro and in vivo.

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Telaprevir 2 (VX-950), an inhibitor of the hepatitis C virus (HCV(a)) NS3-4A protease, is in phase 3 clinical trials. One of the major metabolites of 2 is its P1-(R)-diastereoisomer, 3 (VRT-394), containing an inversion at the chiral center next to the alpha-ketoamide on exchange of a proton with solvent. Compound 3 is approximately 30-fold less active against HCV protease.

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The Ras/Raf/MEK/ERK signal transduction, an oncogenic pathway implicated in a variety of human cancers, is a key target in anticancer drug design. A novel series of pyrimidylpyrrole ERK inhibitors has been identified. Discovery of a conformational change for lead compound 2, when bound to ERK2 relative to antitarget GSK3, enabled structure-guided selectivity optimization, which led to the discovery of 11e, a potent, selective, and orally bioavailable inhibitor of ERK.

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The Ras/Raf/MEK/ERK signal transduction is a key oncogenic pathway implicated in a variety of human cancers. We have identified a novel series of pyrazolylpyrroles as inhibitors of ERK. Aided by the discovery of two distinct binding modes for the pyrazolylpyrrole scaffold, structure-guided optimization culminated in the discovery of 6p, a potent and selective inhibitor of ERK.

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(S)-1-((S)-2-{[1-(4-amino-3-chloro-phenyl)-methanoyl]-amino}-3,3-dimethyl-butanoyl)-pyrrolidine-2-carboxylic acid ((2R,3S)-2-ethoxy-5-oxo-tetrahydro-furan-3-yl)-amide (VX-765) is an orally absorbed prodrug of (S)-3-({1-[(S)-1-((S)-2-{[1-(4-amino-3-chlorophenyl)-methanoyl]-amino}-3,3-dimethyl-butanoyl)-pyrrolidin-2yl]-methanoyl}-amino)-4-oxo-butyric acid (VRT-043198), a potent and selective inhibitor of interleukin-converting enzyme/caspase-1 subfamily caspases. VRT-043198 exhibits 100- to 10,000-fold selectivity against other caspase-3 and -6 to -9. The therapeutic potential of VX-765 was assessed by determining the effects of VRT-043198 on cytokine release by monocytes in vitro and of orally administered VX-765 in several animal models in vivo.

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Akt is a central regulator of cardiomyocyte survival after ischemic injury in vitro and in vivo, but the mechanisms regulating Akt activity in the postischemic cardiomyocyte are not known. Furthermore, although much is known about the detrimental role that the c-Jun N-terminal kinases (JNKs) play in promoting death of cells exposed to various stresses, little is known of the molecular mechanisms by which JNK activation can be protective. We report that JNKs are necessary for the reactivation of Akt after ischemic injury.

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