9H-Carbazole-1-carboxamides as potent and selective JAK2 inhibitors.

The discovery, synthesis, and characterization of 9H-carbazole-1-carboxamides as potent and selective ATP-competitive inhibitors of Janus kinase 2 (JAK2) are discussed. Optimization for JAK family selectivity led to compounds 14 and 21, with greater than 45-fold selectivity for JAK2 over all other members of the JAK kinase family.

Modulation of cofilin phosphorylation by inhibition of the Lim family kinases.

A series of aminothiazoles that are potent inhibitors of LIM kinases 1 and 2 is described. Appropriate choice of substituents led to molecules with good selectivity for either enzyme. An advanced member of the series was shown to effectively interfere with the phosphorylation of the LIM kinases substrate cofilin. Consistent with the important role of the LIM kinases in regulating cytoskeletal structure, treated cells displayed dramatically reduced F-actin content.

Identification and optimization of small molecule antagonists of vasoactive intestinal peptide receptor-1 (VIPR1).

Identification, synthesis and structure-activity relationship of small-molecule VIPR1 antagonists encompassing two chemical series are described.

Synthesis and structure-activity relationships of pyrido[3,2-b]pyrazin-3(4H)-ones and pteridin-7(8H)-ones as corticotropin-releasing factor-1 receptor antagonists.

Pyrido[3,2-b]pyrazin-3(4H)-ones and pteridin-7(8H)-ones were evaluated as corticotropin-releasing factor-1 receptor antagonists. The synthesis, SAR studies and pharmacokinetic evaluation of these analogs are described herein.

Pyrrolo[1,2-f]triazines as JAK2 inhibitors: achieving potency and selectivity for JAK2 over JAK3.

SAR studies of pyrrolo[1,2-f]triazines as JAK2 inhibitors is presented. Achieving JAK2 inhibition selectively over JAK3 is discussed.

Synthesis and in vivo evaluation of cyclic diaminopropane BACE-1 inhibitors.

The synthesis, evaluation, and structure-activity relationships of a set of related constrained diaminopropane inhibitors of BACE-1 are described. The full in vivo profile of an optimized inhibitor in both normal and P-gp deficient mice is compared with data generated in normal rats.

Discovery of matrix metalloproteases selective and activated peptide-doxorubicin prodrugs as anti-tumor agents.

To selectively target doxorubicin (Dox) to tumor tissue and thereby improve the therapeutic index and/or efficacy of Dox, matrix metalloproteinases (MMP) activated peptide-Dox prodrugs were designed and synthesized by coupling MMP-cleavable peptides to Dox. Preferred conjugates were good substrates for MMPs, poor substrates for neprilysin, an off-target proteinase, and stable in blood ex vivo. When administered to mice with HT1080 xenografts, conjugates, such as 19, preferentially released Dox in tumor relative to heart tissue and prevented tumor growth with less marrow toxicity than Dox.

Design, synthesis and structure-activity relationships of novel biarylamine-based Met kinase inhibitors.

Biarylamine-based inhibitors of Met kinase have been identified. Lead compounds demonstrate nanomolar potency in Met kinase biochemical assays and significant activity in the Met-driven GTL-16 human gastric carcinoma cell line. X-ray crystallography revealed that these compounds adopt a bioactive conformation, in the kinase domain, consistent with that previously seen with 2-pyridone-based Met kinase inhibitors. Compound 9b demonstrated potent in vivo antitumor activity in the GTL-16 human tumor xenograft model.

Discovery and Optimization of Novel Pyrazolopyrimidines as Potent and Orally Bioavailable Allosteric HIV-1 Integrase Inhibitors.

The standard of care for HIV-1 infection, highly active antiretroviral therapy (HAART), combines two or more drugs from at least two classes. Even with the success of HAART, new drugs with novel mechanisms are needed to combat viral resistance, improve adherence, and mitigate toxicities. Active site inhibitors of HIV-1 integrase are clinically validated for the treatment of HIV-1 infection. Here we describe allosteric inhibitors of HIV-1 integrase that bind to the LEDGF/p75 interaction site and disrupt the structure of the integrase multimer that is required for the HIV-1 maturation. A series of pyrazolopyrimidine-based inhibitors was developed with a vector in the 2-position that was optimized by structure-guided compound design. This resulted in the discovery of pyrazolopyrimidine 3, which was optimized at the 2- and 7-positions to afford 26 and 29 as potent allosteric inhibitors of HIV-1 integrase that exhibited low nanomolar antiviral potency in cell culture and encouraging PK properties.

Benzo[d]imidazole inhibitors of Coactivator Associated Arginine Methyltransferase 1 (CARM1)--Hit to Lead studies.

Hit to Lead optimization and SAR development led to the identification of the potent and selective benzo[d]imidazole inhibitor (17b) of Co-activator Associated Arginine Methyltransferase (CARM1).

Optimization of pyrazole inhibitors of Coactivator Associated Arginine Methyltransferase 1 (CARM1).

Design, synthesis, and SAR development led to the identification of the potent, novel, and selective pyrazole based inhibitor (7f) of Coactivator Associated Arginine Methyltransferase (CARM1).

Identification of 2-amino-5-(thioaryl)thiazoles as inhibitors of nerve growth factor receptor TrkA.

2-Amino-5-(thioaryl)thiazoles are potent inhibitors of TrkA (e.g., 20h, TrkA IC(50)=0.6 nM) that show anti-proliferative effect in cellular assays. A proposed inhibitor binding mode to TrkA active site is consistent with key SAR observations.

Discovery and preclinical studies of 5-isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-N-(2-methyl-1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine (BMS-645737), an in vivo active potent VEGFR-2 inhibitor.

We report herein a series of substituted N-(1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amines as inhibitors of vascular endothelial growth factor receptor-2 tyrosine kinase. Through structure-activity relationship studies, biochemical potency, pharmacokinetics, and kinase selectivity were optimized to afford BMS-645737 (13), a compound with good preclinical in vivo activity against human tumor xenograft models.

Dihydropyridopyrazinones and dihydropteridinones as corticotropin-releasing factor-1 receptor antagonists: structure-activity relationships and computational modeling.

The CRF antagonist pharmacophore is a heterocyclic ring bearing a critical hydrogen-bond acceptor nitrogen and an orthogonal aromatic ring. CRFR1 antagonists have shown a 40-fold and 200-fold loss in potency against the CRFR1 H199V and M276I mutant receptors, suggesting key interactions with these residues. We have derived a two component computational model that correlates CRFR1 binding affinity within the reported series to antagoinst/H199 complexation energy and M276 hydrophobic contacts.

Matrix metalloproteinase-activated doxorubicin prodrugs inhibit HT1080 xenograft growth better than doxorubicin with less toxicity.

Matrix metalloproteinase (MMP)-activated prodrugs were formed by coupling MMP-cleavable peptides to doxorubicin. The resulting conjugates were excellent in vitro substrates for MMP-2, -9, and -14. HT1080, a fibrosarcoma cell line, was used as a model system to test these prodrugs because these cells, like tumor stromal fibroblasts, expressed several MMPs. In cultured HT1080 cells, simple MMP-cleavable peptides were primarily metabolized by neprilysin, a membrane-bound metalloproteinase. MMP-selective metabolism in cultured HT1080 cells was obtained by designing conjugates that were good MMP substrates but poor neprilysin substrates. To determine how conjugates were metabolized in animals, MMP-selective conjugates were given to mice with HT1080 xenografts and the distribution of doxorubicin was determined. These studies showed that MMP-selective conjugates were preferentially metabolized in HT1080 xenografts, relative to heart and plasma, leading to 10-fold increases in the tumor/heart ratio of doxorubicin. The doxorubicin deposited by a MMP-selective prodrug, compound 6, was more effective than doxorubicin at reducing HT1080 xenograft growth. In particular, compound 6 cured 8 of 10 mice with HT1080 xenografts at doses below the maximum tolerated dose, whereas doxorubicin cured 2 of 20 mice at its maximum tolerated dose. Compound 6 was less toxic than doxorubicin at this efficacious dose because mice treated with compound 6 had no detectable changes in body weight or reticulocytes, a marker for marrow toxicity. Hence, MMP-activated doxorubicin prodrugs have a much higher therapeutic index than doxorubicin using HT1080 xenografts as a preclinical model.

Discovery of the Selective CYP17A1 Lyase Inhibitor BMS-351 for the Treatment of Prostate Cancer.

Efforts to identify a potent, reversible, nonsteroidal CYP17A1 lyase inhibitor with good selectivity over CYP17A1 hydroxylase and CYPs 11B1 and 21A2 for the treatment of castration-resistant prostate cancer (CRPC) culminated in the discovery of BMS-351 (compound 18), a pyridyl biaryl benzimidazole with an excellent in vivo profile. Biological evaluation of BMS-351 at a dose of 1.5 mg in castrated cynomolgus monkeys revealed a remarkable reduction in testosterone levels with minimal glucocorticoid and mineralcorticoid perturbation. Based on a favorable profile, BMS-351 was selected as a candidate for further preclinical evaluation.

Discovery of CC chemokine receptor-3 (CCR3) antagonists with picomolar potency.

Starting with our previously described(20) class of CC chemokine receptor-3 (CCR3) antagonist, we improved the potency by replacing the phenyl linker of 1 with a cyclohexyl linker and by replacing the 4-benzylpiperidine with a 3-benzylpiperidine. The resulting compound, 32, is a potent and selective antagonist of CCR3. SAR studies showed that the 3-acetylphenyl urea of 32 could be replaced with heterocyclic ureas or heterocyclic-substituted phenyl ureas and still maintain the potency (inhibition of eotaxin-induced chemotaxis) of this class of compounds in the low-picomolar range (IC(50) = 10-60 pM), representing some of the most potent CCR3 antagonists reported to date. The potency of 32 for mouse CCR3 (chemotaxis IC(50) = 41 nM) and its oral bioavailability in mice (20% F ) were adequate to assess the efficacy in animal models of allergic airway inflammation. Oral administration of 32 reduced eosinophil recruitment into the lungs in a dose-dependent manner in these animal models. On the basis of its overall potency, selectivity, efficacy, and safety profile, the benzenesulfonate salt of 32, designated DPC168, entered phase I clinical trials.

Structure-Based Design of Selective Janus Kinase 2 Imidazo[4,5-d]pyrrolo[2,3-b]pyridine Inhibitors.

Early hit to lead work on a pyrrolopyridine chemotype provided access to compounds with biochemical and cellular potency against Janus kinase 2 (JAK2). Structure-based drug design along the extended hinge region of JAK2 led to the identification of an important H-bond interaction with the side chain of Tyr 931, which improved JAK family selectivity. The 4,5-dimethyl thiazole analogue 18 demonstrated high levels of JAK family selectivity and was identified as a promising lead for the program.

Discovery of a Highly Selective JAK2 Inhibitor, BMS-911543, for the Treatment of Myeloproliferative Neoplasms.

JAK2 kinase inhibitors are a promising new class of agents for the treatment of myeloproliferative neoplasms and have potential for the treatment of other diseases possessing a deregulated JAK2-STAT pathway. X-ray structure and ADME guided refinement of C-4 heterocycles to address metabolic liability present in dialkylthiazole 1 led to the discovery of a clinical candidate, BMS-911543 (11), with excellent kinome selectivity, in vivo PD activity, and safety profile.

Synthesis, structure-activity relationships, and in vivo properties of 3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-ones as corticotropin-releasing factor-1 receptor antagonists.

Corticotropin releasing factor (CRF) is the primary regulator of the hypothalamus-pituitary-adrenal (HPA) axis, coordinating the endocrine, behavioral, and autonomic responses to stress. It has been postulated that small molecules that can antagonize the binding of CRF1 to its receptor may serve as a treatment for anxiety-related and/or affective disorders. Members within a series of 3,4-dihydro-1H-pyrido[2,3-b]pyrazin-2-ones, exemplified by compound 2 (IC50 = 0.70 nM), were found to be very potent antagonists of CRF1. Compound 8w showed high CRF1 receptor binding affinity and was examined further in vivo. The compound was efficacious in a defensive withdrawal model of anxiety in rats and had a long half-life and reasonable oral bioavailability in dog pharmacokinetic studies.