Discovery of Pyrrolopyrazine Carboxamide Derivatives as Potent and Selective FGFR2/3 Inhibitors that Overcome Mutant Resistance.

Fibroblast growth factor receptors (FGFRs) are established oncogenic drivers in various solid tumors. However, the approved FGFR inhibitors face challenges with acquired resistance and dose-limiting adverse effects associated with FGFR1/4 inhibition, limiting therapeutic efficacy. Herein, we systematically explored linker and electrophile moieties based on the pyrrolopyrazine carboxamide core and identified aniline α-fluoroacrylamide as an effective covalent warhead.

Preclinical metabolism and disposition of [C]GFH009, a novel selective CDK9 inhibitor.

GFH009 is a potent and highly selective cyclin-dependent kinase 9 (CDK9) inhibitor currently under phase II clinical trials. In this study, we investigated the metabolism and disposition of GFH009 in Sprague-Dawley (SD) rats, as well as metabolism of CD-1 mouse, SD rat, beagle dog, cynomolgus monkey, and human.A radiolabelled study indicated that [C]GFH009 was quickly and widely distributed throughout the body, but presented low levels in brain, testis, and epididymis after a single intravenous dose of 6 mg (100 µCi)/kg to SD rats.

Discovery of a Novel Macrocyclic Noncovalent CDK7 Inhibitor for Cancer Therapy.

Cyclin-dependent kinase 7 (CDK7) is a key regulator of the cell cycle and transcription, making it a promising target for cancer therapy. Although current CDK7 inhibitors have improved in their selectivity and druglike properties, CDK7 inhibitors have failed to progress through clinical development due to severe gastrointestinal and hematotoxic side effects. To mitigate these limitations, we have developed novel, macrocyclic, noncovalent CDK7 hit compounds and using a macrocyclization platform that has optimized these compounds from SY-5609, a leading clinical asset.

The pharmacodynamic and mechanistic foundation for the antineoplastic effects of GFH009, a potent and highly selective CDK9 inhibitor for the treatment of hematologic malignancies.

To evade cell cycle controls, malignant cells rely upon rapid expression of select proteins to mitigate proapoptotic signals resulting from damage caused by both cancer treatments and unchecked over-proliferation. Cyclin-dependent kinase 9 (CDK9)-dependent signaling induces transcription of downstream oncogenes promoting tumor growth, especially in hyperproliferative 'oncogene-addicted' cancers, such as human hematological malignancies (HHMs). GFH009, a potent, highly selective CDK9 small molecule inhibitor, demonstrated antiproliferative activity in assorted HHM-derived cell lines, inducing apoptosis at IC50 values below 0.

Development and validation of a sensitive UPLC-MS/MS analytical method for GFH009 in rat plasma and its application to toxicokinetics studies.

GFH009 is a potent, highly selective, small molecule that targets and inhibits the activity of the CDK9/cyclin T1 regulatory complex of P-TEFb. This study aimed to develop and validate a highly selective and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for precise quantification of GFH009 in rat plasma. This method was subsequently employed for conducting toxicokinetic studies of GFH009 in rats.

Global profiling of AMG510 modified proteins identified tumor suppressor KEAP1 as an off-target.

KRAS inhibitor AMG510 covalently modifies the G12C residue and inactivates the KRAS/G12C function. Because there are many reactive cysteines in the proteome, it is important to characterize AMG510 on-target modification and off-targets. Here, we presented a streamlined workflow to measure abundant AMG510 modified peptides including that of KRAS/G12C by direct profiling, and a pan-AMG510 antibody peptide IP workflow to profile less abundant AMG510 off-targets.

Synthesis and Structure-Activity Relationship of Tetra-Substituted Cyclohexyl Diol Inhibitors of Proviral Insertion of Moloney Virus (PIM) Kinases.

Overexpression of PIM 1, 2, and 3 kinases is frequently observed in many malignancies. Previously, we discovered a potent and selective pan-PIM kinase inhibitor, compound , currently in phase I clinical trials. In this work, we were interested in replacing the amino group on the cyclohexane ring in compound with a hydroxyl group.

Design and synthesis of potent RSK inhibitors.

Utilizing the already described 3,4-bi-aryl pyridine series as a starting point, incorporation of a second ring system with a hydrogen bond donor and additional hydrophobic contacts yielded the azaindole series which exhibited potent, picomolar RSK2 inhibition and the most potent in vitro target modulation seen thus far for a RSK inhibitor. In the context of the more potent core, several changes at the phenol moiety were assessed to potentially find a tool molecule appropriate for in vivo evaluation.

Discovery of an Orally Bioavailable Dual PI3K/mTOR Inhibitor Based on Sulfonyl-Substituted Morpholinopyrimidines.

The discovery and optimization of a series of 2-morpholino-pyrimidine derivatives containing various sulfonyl side chains at the C position led to the identification of compound as a potent dual PI3K/mTOR inhibitor. It exhibited high inhibitory activity against PI3Kα/β/γ/δ (IC = 20/376/204/46 nM) and mTOR (IC = 189 nM), potent functional suppression of AKT phosphorylation (IC = 196 nM), and excellent antiproliferative effects on a panel of cancer cells. Enzymic data and modeling simulation indicate that a cyclopropyl ring on the C sulfone chain and a fluorine on the C aminopyridyl moiety are responsible for its maintained PI3K activity and enhanced mTOR potency, respectively.

Discovery of N-aryl-N'-pyrimidin-4-yl ureas as irreversible L858R/T790M mutant selective epidermal growth factor receptor inhibitors.

A novel series of N-aryl-N'-pyrimidin-4-yl ureas has been optimized to afford potent and selective inhibitors of the EGFR L858R/T790M. The most representative compound 28 showed high activity against EGFR L858R/T790M kinase (IC = 4 nM) and 22-fold selectivity against wild type EGFR. Moreover, compound 28 potently inhibited EGFR L858R/T790M phosphorylation (IC = 41 nM) and cellular proliferation (IC = 37 nM) in the H1975 cell line, while being significantly less toxic to A431 cells.

Discovery of novel substituted octahydropyrrolo[3,4-c]pyrroles as dual orexin receptor antagonists for insomnia treatment.

A series of octahydropyrrolo[3,4-c]pyrroles were synthesized and evaluated by orexin 1 and 2 receptor (OX R) antagonists assays. Compound 14l with potent OXR antagonist activity and suitable pharmacokinetic behavior was chosen to be investigated in an EEG study, which demonstrated effects of sleep promotion comparable to Suvorexant. Furthermore, the di-fluro substituted analogs exhibited reduced hERG inhibition while maintaining moderate potency.

Design, synthesis and structure activity relationship of potent pan-PIM kinase inhibitors derived from the pyridyl carboxamide scaffold.

The Pim proteins (1, 2 and 3) are serine/threonine kinases that have been found to be upregulated in many hematological malignancies and solid tumors. As a result of overlapping functions among the three isoforms, inhibition of all three Pim kinases has become an attractive strategy for cancer therapy. Herein we describe our efforts in identifying potent pan-PIM inhibitors that are derived from our previously reported pyridyl carboxamide scaffold as part of a medicinal chemistry strategy to address metabolic stability.

Discovery of imidazo[1,2-a]-pyridine inhibitors of pan-PI3 kinases that are efficacious in a mouse xenograft model.

Alterations in PI3K/AKT signaling are known to be implicated with tumorigenesis. The PI3 kinases family of lipid kinases has been an attractive therapeutic target for cancer treatment. Imidazopyridine compound 1, a potent, selective, and orally available pan-PI3K inhibitor, identified by scaffold morphing of a benzothiazole hit, was further optimized in order to achieve efficacy in a PTEN-deleted A2780 ovarian cancer mouse xenograft model.

Discovery of potent and orally bioavailable inhibitors of Human Uric Acid Transporter 1 (hURAT1) and binding mode prediction using homology model.

This Letter describes the discovery of a series of potent inhibitors of Human Uric Acid Transporter 1 (hURAT1). Lead generation and optimization via 3D pharmacophore analysis resulted in compound 41. With an IC50 of 33.

Identification of N-(4-((1R,3S,5S)-3-Amino-5-methylcyclohexyl)pyridin-3-yl)-6-(2,6-difluorophenyl)-5-fluoropicolinamide (PIM447), a Potent and Selective Proviral Insertion Site of Moloney Murine Leukemia (PIM) 1, 2, and 3 Kinase Inhibitor in Clinical Trials for Hematological Malignancies.

Pan proviral insertion site of Moloney murine leukemia (PIM) 1, 2, and 3 kinase inhibitors have recently begun to be tested in humans to assess whether pan PIM kinase inhibition may provide benefit to cancer patients. Herein, the synthesis, in vitro activity, in vivo activity in an acute myeloid leukemia xenograft model, and preclinical profile of the potent and selective pan PIM kinase inhibitor compound 8 (PIM447) are described. Starting from the reported aminopiperidyl pan PIM kinase inhibitor compound 3, a strategy to improve the microsomal stability was pursued resulting in the identification of potent aminocyclohexyl pan PIM inhibitors with high metabolic stability.

Discovery of Potent and Selective RSK Inhibitors as Biological Probes.

While the p90 ribosomal S6 kinase (RSK) family has been implicated in multiple tumor cell functions, the full understanding of this kinase family has been restricted by the lack of highly selective inhibitors. A bis-phenol pyrazole was identified from high-throughput screening as an inhibitor of the N-terminal kinase of RSK2. Structure-based drug design using crystallography, conformational analysis, and scaffold morphing resulted in highly optimized difluorophenol pyridine inhibitors of the RSK kinase family as demonstrated cellularly by the inhibition of YB1 phosphorylation.

Structure-Based Drug Design of Novel, Potent, and Selective Azabenzimidazoles (ABI) as ATR Inhibitors.

Compound 13 was discovered through morphing of the ATR biochemical HTS hit 1. The ABI series was potent and selective for ATR. Incorporation of a 6-azaindole afforded a marked increase in cellular potency but was associated with poor PK and hERG ion channel inhibition.

Structure-Based Drug Design of Novel Potent and Selective Tetrahydropyrazolo[1,5-a]pyrazines as ATR Inhibitors.

A saturation strategy focused on improving the selectivity and physicochemical properties of ATR inhibitor HTS hit 1 led to a novel series of highly potent and selective tetrahydropyrazolo[1,5-a]pyrazines. Use of PI3Kα mutants as ATR crystal structure surrogates was instrumental in providing cocrystal structures to guide the medicinal chemistry designs. Detailed DMPK studies involving cyanide and GSH as trapping agents during microsomal incubations, in addition to deuterium-labeled compounds as mechanistic probes uncovered the molecular basis for the observed CYP3A4 TDI in the series.

Structure Guided Optimization, in Vitro Activity, and in Vivo Activity of Pan-PIM Kinase Inhibitors.

Proviral insertion of Moloney virus (PIM) 1, 2, and 3 kinases are serine/threonine kinases that normally function in survival and proliferation of hematopoietic cells. As high expression of PIM1, 2, and 3 is frequently observed in many human malignancies, including multiple myeloma, non-Hodgkins lymphoma, and myeloid leukemias, there is interest in determining whether selective PIM inhibition can improve outcomes of these human cancers. Herein, we describe our efforts toward this goal.

Novel potent and selective inhibitors of p90 ribosomal S6 kinase reveal the heterogeneity of RSK function in MAPK-driven cancers.

Unlabelled: The p90 ribosomal S6 kinase (RSK) family of serine/threonine kinases is expressed in a variety of cancers and its substrate phosphorylation has been implicated in direct regulation of cell survival, proliferation, and cell polarity. This study characterizes and presents the most selective and potent RSK inhibitors known to date, LJH685 and LJI308. Structural analysis confirms binding of LJH685 to the RSK2 N-terminal kinase ATP-binding site and reveals that the inhibitor adopts an unusual nonplanar conformation that explains its excellent selectivity for RSK family kinases.

2-Amino-7-substituted benzoxazole analogs as potent RSK2 inhibitors.

2-Amino-7-substituted benzoxazole analogs were identified by HTS as inhibitors of RSK2. Molecular modeling and medicinal chemistry techniques were employed to explore the SAR for this series with a focus of improving in vitro and target modulation potency and physicochemical properties.

Pan-PIM kinase inhibition provides a novel therapy for treating hematologic cancers.

Purpose: PIM kinases have been shown to act as oncogenes in mice, with each family member being able to drive progression of hematologic cancers. Consistent with this, we found that PIMs are highly expressed in human hematologic cancers and show that each isoform has a distinct expression pattern among disease subtypes. This suggests that inhibitors of all three PIMs would be effective in treating multiple hematologic malignancies.

Structure guided optimization of a fragment hit to imidazopyridine inhibitors of PI3K.

PI3 kinases are a family of lipid kinases mediating numerous cell processes such as proliferation, migration and differentiation. The PI3 Kinase pathway is often de-regulated in cancer through PI3Kα overexpression, gene amplification, mutations and PTEN phosphatase deletion. PI3K inhibitors represent therefore an attractive therapeutic modality for cancer treatment.

In vitro properties of antimicrobial bromotyrosine alkaloids.

A bromotyrosine alkaloid family of antimicrobial agents was synthesized using the known structure of a natural inhibitor of the mycobacterial mycothiol S-conjugate amidase (MCA) as a template. This series of compounds represents a novel class of anti-infective agents against Gram-positive pathogens, including mycobacteria and meticillin- and vancomycin-resistant Staphylococcus aureus. The fact that these compounds are active against mycobacterial strains in which the MCA gene is deleted and against Gram-positive bacteria lacking mycothiol suggests the existence of an alternative target for these compounds.