Publications by authors named "Anthony Ndifor"

6 Publications

  • Page 1 of 1

Substituted Azabicyclo[2.2.1]heptanes as Selective Orexin-1 Antagonists: Discovery of JNJ-54717793.

ACS Med Chem Lett 2020 Oct 27;11(10):2002-2009. Epub 2020 Apr 27.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121, United States.

The orexin system consists of two neuropeptides (orexin-A and orexin-B) that exert their mode of action on two receptors (orexin-1 and orexin-2). While the role of the orexin-2 receptor is established as an important modulator of sleep wake states, the role of the orexin-1 receptor is believed to play a role in addiction, panic, or anxiety. In this manuscript, we describe the optimization of a nonselective substituted azabicyclo[2.2.1]heptane dual orexin receptor antagonist (DORA) into orally bioavailable, brain penetrating, selective orexin-1 receptor (OX1R) antagonists. This resulted in the discovery of our first candidate for clinical development, JNJ-54717793.
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http://dx.doi.org/10.1021/acsmedchemlett.0c00085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549262PMC
October 2020

Characterization of JNJ-42847922, a Selective Orexin-2 Receptor Antagonist, as a Clinical Candidate for the Treatment of Insomnia.

J Pharmacol Exp Ther 2015 Sep 15;354(3):471-82. Epub 2015 Jul 15.

Janssen Research & Development, LLC, San Diego, California

Dual orexin receptor antagonists have been shown to promote sleep in various species, including humans. Emerging research indicates that selective orexin-2 receptor (OX2R) antagonists may offer specificity and a more adequate sleep profile by preserving normal sleep architecture. Here, we characterized JNJ-42847922 ([5-(4,6-dimethyl-pyrimidin-2-yl)-hexahydro-pyrrolo[3,4-c]pyrrol-2-yl]-(2-fluoro-6-[1,2,3]triazol-2-yl-phenyl)-methanone), a high-affinity/potent OX2R antagonist. JNJ-42847922 had an approximate 2-log selectivity ratio versus the human orexin-1 receptor. Ex vivo receptor binding studies demonstrated that JNJ-42847922 quickly occupied OX2R binding sites in the rat brain after oral administration and rapidly cleared from the brain. In rats, single oral administration of JNJ-42847922 (3-30 mg/kg) during the light phase dose dependently reduced the latency to non-rapid eye movement (NREM) sleep and prolonged NREM sleep time in the first 2 hours, whereas REM sleep was minimally affected. The reduced sleep onset and increased sleep duration were maintained upon 7-day repeated dosing (30 mg/kg) with JNJ-42847922, then all sleep parameters returned to baseline levels following discontinuation. Although the compound promoted sleep in wild-type mice, it had no effect in OX2R knockout mice, consistent with a specific OX2R-mediated sleep response. JNJ-42847922 did not increase dopamine release in rat nucleus accumbens or produce place preference in mice after subchronic conditioning, indicating that the compound lacks intrinsic motivational properties in contrast to zolpidem. In a single ascending dose study conducted in healthy subjects, JNJ-42847922 increased somnolence and displayed a favorable pharmacokinetic and safety profile for a sedative/hypnotic, thus emerging as a promising candidate for further clinical development for the treatment of insomnia.
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http://dx.doi.org/10.1124/jpet.115.225466DOI Listing
September 2015

Novel benzamide-based histamine h3 receptor antagonists: the identification of two candidates for clinical development.

ACS Med Chem Lett 2015 Apr 13;6(4):450-4. Epub 2015 Mar 13.

Janssen Pharmaceutical Company, a division of Johnson & Johnson Pharmaceutical Research & Development L.L.C. , 3210 Merryfield Row, San Diego, California 92121, United States.

The preclinical characterization of novel phenyl(piperazin-1-yl)methanones that are histamine H3 receptor antagonists is described. The compounds described are high affinity histamine H3 antagonists. Optimization of the physical properties of these histamine H3 antagonists led to the discovery of several promising lead compounds, and extensive preclinical profiling aided in the identification of compounds with optimal duration of action for wake promoting activity. This led to the discovery of two development candidates for Phase I and Phase II clinical trials.
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http://dx.doi.org/10.1021/ml5005156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4394347PMC
April 2015

Context-dependent role of angiopoietin-1 inhibition in the suppression of angiogenesis and tumor growth: implications for AMG 386, an angiopoietin-1/2-neutralizing peptibody.

Mol Cancer Ther 2010 Oct;9(10):2641-51

Department of Oncology Research, Amgen, Inc., Thousand Oaks, California 91320, USA.

AMG 386 is an investigational first-in-class peptide-Fc fusion protein (peptibody) that inhibits angiogenesis by preventing the interaction of angiopoietin-1 (Ang1) and Ang2 with their receptor, Tie2. Although the therapeutic value of blocking Ang2 has been shown in several models of tumorigenesis and angiogenesis, the potential benefit of Ang1 antagonism is less clear. To investigate the consequences of Ang1 neutralization, we have developed potent and selective peptibodies that inhibit the interaction between Ang1 and its receptor, Tie2. Although selective Ang1 antagonism has no independent effect in models of angiogenesis-associated diseases (cancer and diabetic retinopathy), it induces ovarian atrophy in normal juvenile rats and inhibits ovarian follicular angiogenesis in a hormone-induced ovulation model. Surprisingly, the activity of Ang1 inhibitors seems to be unmasked in some disease models when combined with Ang2 inhibitors, even in the context of concurrent vascular endothelial growth factor inhibition. Dual inhibition of Ang1 and Ang2 using AMG 386 or a combination of Ang1- and Ang2-selective peptibodies cooperatively suppresses tumor xenograft growth and ovarian follicular angiogenesis; however, Ang1 inhibition fails to augment the suppressive effect of Ang2 inhibition on tumor endothelial cell proliferation, corneal angiogenesis, and oxygen-induced retinal angiogenesis. In no case was Ang1 inhibition shown to (a) confer superior activity to Ang2 inhibition or dual Ang1/2 inhibition or (b) antagonize the efficacy of Ang2 inhibition. These results imply that Ang1 plays a context-dependent role in promoting postnatal angiogenesis and that dual Ang1/2 inhibition is superior to selective Ang2 inhibition for suppression of angiogenesis in some postnatal settings.
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http://dx.doi.org/10.1158/1535-7163.MCT-10-0213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4430860PMC
October 2010

Use of tissue cross-reactivity studies in the development of antibody-based biopharmaceuticals: history, experience, methodology, and future directions.

Toxicol Pathol 2010 Dec 6;38(7):1138-66. Epub 2010 Oct 6.

Therapeutic Area Lead, Biocorrection, Drug Safety Research and Development, Pfizer, Andover, Massachusetts 01810, USA.

Tissue cross-reactivity (TCR) studies are screening assays recommended for antibody and antibody-like molecules that contain a complementarity-determining region (CDR), primarily to identify off-target binding and, secondarily, to identify sites of on-target binding that were not previously identified. At the present time, TCR studies involve the ex vivo immunohistochemical (IHC) staining of a panel of frozen tissues from humans and animals, are conducted prior to dosing humans, and results are filed with the initial IND/CTA to support first-in-human clinical trials. In some cases, a robust TCR assay cannot be developed, and in these cases the lack of a TCR assay should not prevent a program from moving forward. The TCR assay by itself has variable correlation with toxicity or efficacy. Therefore, any findings of interest should be further evaluated and interpreted in the context of the overall pharmacology and safety assessment data package. TCR studies are generally not recommended for surrogate molecules or for comparability assessments in the context of manufacturing/cell line changes. Overall, the design, implementation, and interpretation of TCR studies should follow a case-by-case approach.
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http://dx.doi.org/10.1177/0192623310382559DOI Listing
December 2010

Suppression of angiogenesis and tumor growth by selective inhibition of angiopoietin-2.

Cancer Cell 2004 Nov;6(5):507-16

Amgen, Thousand Oaks, California 91320, USA.

Angiopoietin-2 (Ang2) exhibits broad expression in the remodeling vasculature of human tumors but very limited expression in normal tissues, making it an attractive candidate target for antiangiogenic cancer therapy. To investigate the functional consequences of blocking Ang2 activity, we generated antibodies and peptide-Fc fusion proteins that potently and selectively neutralize the interaction between Ang2 and its receptor, Tie2. Systemic treatment of tumor-bearing mice with these Ang2-blocking agents resulted in tumor stasis, followed by elimination of all measurable tumor in a subset of animals. These effects were accompanied by reduced endothelial cell proliferation, consistent with an antiangiogenic therapeutic mechanism. Anti-Ang2 therapy also prevented VEGF-stimulated neovascularization in a rat corneal model of angiogenesis. These results imply that specific Ang2 inhibition may represent an effective antiangiogenic strategy for treating patients with solid tumors.
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http://dx.doi.org/10.1016/j.ccr.2004.09.030DOI Listing
November 2004