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The concentrations of LSN3154567 in the dog plasma samples.

NAMPT, an enzyme essential for NAD+ biosynthesis, has been extensively studied as an anticancer target for developing potential novel therapeutics. Several NAMPT inhibitors have been discovered, some of which have been subjected to clinical investigations. Yet, the on-target hematological and retinal toxicities have hampered their clinical development. In this study, we report the discovery of a unique NAMPT inhibitor, LSN3154567. This molecule is highly selective and has a potent and broad spectrum of anticancer activity. Its inhibitory activity can be rescued with nicotinic acid (NA) against the cell lines proficient, but not those deficient in NAPRT1, essential for converting NA to NAD+. LSN3154567 also exhibits robust efficacy in multiple tumor models deficient in NAPRT1. Importantly, this molecule when coadministered with NA does not cause observable retinal and hematological toxicities in the rodents, yet still retains robust efficacy. Thus, LSN3154567 has the potential to be further developed clinically into a novel cancer therapeutic. Mol Cancer Ther; 16(12); 2677–88. ©2017 AACR.

Table S1: anti-proliferative activity of LSN3154567 against different cancer cell lines; Table S2: effects of NAM on the anti-proliferative activity of LSN3154567

NAMPT, an enzyme essential for NAD+ biosynthesis, has been extensively studied as an anticancer target for developing potential novel therapeutics. Several NAMPT inhibitors have been discovered, some of which have been subjected to clinical investigations. Yet, the on-target hematological and retinal toxicities have hampered their clinical development. In this study, we report the discovery of a unique NAMPT inhibitor, LSN3154567. This molecule is highly selective and has a potent and broad spectrum of anticancer activity. Its inhibitory activity can be rescued with nicotinic acid (NA) against the cell lines proficient, but not those deficient in NAPRT1, essential for converting NA to NAD+. LSN3154567 also exhibits robust efficacy in multiple tumor models deficient in NAPRT1. Importantly, this molecule when coadministered with NA does not cause observable retinal and hematological toxicities in the rodents, yet still retains robust efficacy. Thus, LSN3154567 has the potential to be further developed clinically into a novel cancer therapeutic. Mol Cancer Ther; 16(12); 2677–88. ©2017 AACR.

Acute myeloid leukemia is associated with the abnormal proliferation of myeloid progenitor cells unable to differentiate. Somatic gain-of-function mutations in isocitrate dehydrogenase (IDH) 1 occur in 10% of newly diagnosed AML patients. IDH1 mutations cause intracellular accumulation of the oncometabolite, 2-hydroxyglutarate (2-HG), which results in a hyper-methylation phenotype and a block in differentiation. Inhibitors of IDH1 mutant enzyme reduce levels of 2-HG, which relieves the differentiation block allowing AML cells to achieve terminal maturation. Recently, Ivosidenib, an IDH1 inhibitor, has been approved for use in AML patients. However, based on clinical findings, a fraction of the IDH1 mutant AML patients treated with Ivosidenib are primary refractory or relapse while on therapy. This raises the need for development of more potent inhibitors targeting IDH1. Lilly Research Laboratories have developed a potent covalent inhibitor of mutant IDH1, LY3410738 that modifies a single cysteine (Cys269) in an allosteric binding pocket and rapidly inactivates the enzyme, selectively inhibiting 2-HG production without affecting alpha-ketoglutarate (a-KG) levels. Here, we have assessed the activity of LY3410738 in IDH1 mutated patient-derived AML models and AML cell lines engineered to express wild-type IDH1 or mutant IDH1R132H. In vitro, LY3410738 displayed greater potency for inhibition of 2-HG production and differentiation of the IDH1 mutant cells compared to AG-120. Similarly, in vivo, we observed sustained 2-HG inhibition leading to a more robust and durable efficacy for LY3410738 with respect to AG-120. We next evaluated the combination activity of LY3410738 with Cytarabine and Azacitidine or the FLT3 inhibitor Midostaurin, the latter in FLT3-mutated AML. Combining LY3410738 with the chemotherapeutics resulted in increased efficacy, exhibiting a potent anti-leukemic effect, reduction of 2-HG level, and enhanced differentiation of the leukemic blasts in the mice. In addition, since IDH1 mutant AML cells have been shown to strongly depend on the anti-apoptotic Bcl-2 for the survival, we also combined LY3410738 with FDA approved Bcl-2 inhibitor, venetoclax. In vitro, isogenic cells with IDH1R132H mutation were more sensitive to the combination than wild-type IDH1-expressing cells. Importantly, the combination of LY3410738 with Venetoclax was also efficacious in an AML xenograft model derived from a patient refractory to AG-120. In conclusion, LY3410738 exhibits enhanced efficacy in IDH1 mutant AML PDX models in combination with Cytarabine, Azacitidine, Midostaurin and Venetoclax and demonstrates improved potency and durability compared to Ivosidenib. Citation Format: Vivian Salama, Nathan Brooks, Anna Skwarska, Lisa Kays, Paul Milligan, Katherine Newell, Kenneth Roth, Sandaruwan Geeganage, Raymond Gilmour, Steven M. Chan, Jean-Emmanuel Sarry, Mary Sabatier, Courtney DiNardo, Marina Konopleva. LY3410738, a novel inhibitor of mutant IDH1 is more effective than Ivosidenib and potentiates antileukemic activity of standard chemotherapy in preclinical models of acute myeloid leukemia (AML) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6417.

SummaryLY3009120 is a pan-RAF and RAF dimer inhibitor that inhibits all RAF isoforms and occupies both protomers in RAF dimers. Biochemical and cellular analyses revealed that LY3009120 inhibits ARAF, BRAF, and CRAF isoforms with similar affinity, while vemurafenib or dabrafenib have little or modest CRAF activity compared to their BRAF activities. LY3009120 induces BRAF-CRAF dimerization but inhibits the phosphorylation of downstream MEK and ERK, suggesting that it effectively inhibits the kinase activity of BRAF-CRAF heterodimers. Further analyses demonstrated that LY3009120 also inhibits various forms of RAF dimers including BRAF or CRAF homodimers. Due to these unique properties, LY3009120 demonstrates minimal paradoxical activation, inhibits MEK1/2 phosphorylation, and exhibits anti-tumor activities across multiple models carrying KRAS, NRAS, or BRAF mutation.

The world that social work exists in is no longer defined by traditional physical settings and boundaries, such as schools, agencies, or even offices. With the advent of the Internet and digital communications, social work now exists in a far more complex reality, with clients and social workers engaging across multiple platforms, and sometimes even unintentionally and without one another's awareness. The implications of this can be ethical, practical, regulatory, and personal. This article explores these areas of concern and suggests strategies professionals can use to navigate these complex issues related to technology and clinical practice.

Somatic gain-of-function mutations in IDH1 have been identified in multiple tumor types including AML, glioma, cholangiocarcinoma and chondrosarcoma. The neo-enzymatic activity of mutant IDH1 results in accumulation of the oncometabolite 2-hydroxyglutarate (2-HG), leading to a hyper-methylation phenotype, a block in cell differentiation, and tumor growth. Using a structure-based drug design approach, we have developed a highly potent covalent inhibitor of mutant IDH1. LY3410738 modifies a single cysteine (Cys269) in the allosteric binding pocket and rapidly inactivates the enzyme with a KI/Kinact = 84,257 M-1sec-1. The compound selectively inhibits the 2-HG in IDH1 mutant tumor cells without depleting the levels of a-ketoglutarate. Using patient-derived primary AML cells, we demonstrated that LY3410738 was more potent than AG120 in reversing the block in differentiation associated with IDH1 mutant activity. In vivo, LY3410738 displayed prolonged pharmacodynamic activity, depleting 2-HG levels in tumors at low circulating exposures and for an extended time after clearance of compound. Importantly, LY3410738 has the ability to cross the blood-brain barrier and can achieve concentrations in the brain that exceed those needed to engage the target. Consistent with this, LY3410738 effectively inhibits 2HG in orthotopic glioma models. Using patient-derived IDH1 mutant orthotopic AML models, we demonstrated that LY3410738 effectively inhibited 2-HG, induced differentiation, and cleared AML from mice. Collectively, LY3410738 represents the first covalent brain-penetrant mutant IDH1 inhibitor with potential for Best-in-Class activity. Citation Format: Nathan Brooks, Robin DeWalt, Serge Boulet, ZhaoHai Lu, Lisa Kays, Rachel cavitt, Sandra Gomez, John Strelow, Paul Milligan, Kenneth Roth, Renato Bauer, Stephen Antonysamy, Patric Hahn, Zoran Rankovic, Denis McCann, Gary Mo, Ramon Tiu, Timothy Burkholder, Sandaruwan Geeganage, Raymond Gilmour. Identification and characterization of LY3410738, a novel covalent inhibitor of cancer-associated mutant Isocitrate Dehydrogenase 1 (IDH1) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-274.

SDF-1 and CXCR4 are a chemokine and chemokine receptor pair playing critical roles in tumorigenesis. Overexpression of CXCR4 is a hallmark of many hematological malignancies including acute myeloid leukemia, chronic lymphocytic leukemia and non-Hodgkin's lymphoma, and generally correlates with a poor prognosis. In this study, we developed a humanized anti-CXCR4 monoclonal antibody, LY2624587 as a potent CXCR4 antagonist that was advanced into clinical study for cancer. LY2624587 blocked SDF-1 binding to CXCR4 with an IC50 of 0.26 nM, and inhibited SDF-1-induced GTP binding with a Kb of 0.66 nM. In human lymphoma U937 and leukemia CCRF-CEM cells expressing endogenous CXCR4, LY2624587 inhibited SDF-1-induced cell migration with IC50 values of 3.7 and 0.26 nM, respectively. This antibody also inhibited CXCR4 and SDF-1 mediated cell signaling including activation of MAPK and AKT in tumor cells expressing CXCR4. Bifocal microscopic and flow cytometry analyses revealed that LY2624587 mediated receptor internalization and caused CXCR4 down-regulation on the cell surface. In human hematologic cancer cells, LY2624587 caused dose dependent apoptosis in vitro and in vivo. In mouse xenograft models developed with human leukemia and lymphoma cells expressing high levels of CXCR4, LY2624587 exhibited dose-dependent tumor growth inhibition and provided significant survival benefit in a disseminated lymphoma model. Collectively, we have demonstrated that CXCR4 inhibition by LY2624587 has the potential for the treatment of human hematological malignancies.

The RAS-RAF-MEK-MAPK cascade is an essential signaling pathway, with activation typically mediated through cell surface receptors. The kinase inhibitors vemurafenib and dabrafenib, which target oncogenic BRAF V600E, have shown significant clinical efficacy in melanoma patients harboring this mutation. Because of paradoxical pathway activation, both agents were demonstrated to promote growth and metastasis of tumor cells with RAS mutations in preclinical models and are contraindicated for treatment of cancer patients with BRAF WT background, including patients with KRAS or NRAS mutations. In order to eliminate the issues associated with paradoxical MAPK pathway activation and to provide therapeutic benefit to patients with RAS mutant cancers, we sought to identify a compound not only active against BRAF V600E but also wild type BRAF and CRAF. On the basis of its superior in vitro and in vivo profile, compound 13 was selected for further development and is currently being evaluated in phase I clinical studies.

Emerging evidence demonstrates that stromal cell-derived factor 1 (SDF-1) and CXCR4, a chemokine and chemokine receptor pair, play important roles in tumorigenesis. In this report, we describe a small cyclic peptide, LY2510924, which is a potent and selective CXCR4 antagonist currently in phase II clinical studies for cancer. LY2510924 specifically blocked SDF-1 binding to CXCR4 with IC50 value of 0.079 nmol/L, and inhibited SDF-1–induced GTP binding with Kb value of 0.38 nmol/L. In human lymphoma U937 cells expressing endogenous CXCR4, LY2510924 inhibited SDF-1–induced cell migration with IC50 value of 0.26 nmol/L and inhibited SDF-1/CXCR4-mediated intracellular signaling. LY2510924 exhibited a concentration-dependent inhibition of SDF-1–stimulated phospho-ERK and phospho-Akt in tumor cells. Biochemical and cellular analyses revealed that LY2510924 had no apparent agonist activity. Pharmacokinetic analyses suggested that LY2510924 had acceptable in vivo stability and a pharmacokinetic profile similar to a typical small-molecular inhibitor in preclinical species. LY2510924 showed dose-dependent inhibition of tumor growth in human xenograft models developed with non–Hodgkin lymphoma, renal cell carcinoma, lung, and colon cancer cells that express functional CXCR4. In MDA-MB-231, a breast cancer metastatic model, LY2510924 inhibited tumor metastasis by blocking migration/homing process of tumor cells to the lung and by inhibiting cell proliferation after tumor cell homing. Collectively, the preclinical data support further investigation of LY2510924 in clinical studies for cancer. Mol Cancer Ther; 14(2); 480–90. ©2014 AACR.

LY2603618 is an inhibitor of checkpoint kinase 1 (CHK1), an important regulator of the DNA damage checkpoints. Preclinical experiments analyzed NCI-H2122 and NCI-H441 NSCLC cell lines and in vitro/in vivo models treated with pemetrexed and LY2603618 to provide rationale for evaluating this combination in a clinical setting. Combination treatment of LY2603618 with pemetrexed arrested DNA synthesis following initiation of S-phase in cells. Experiments with tumor-bearing mice administered the combination of LY2603618 and pemetrexed demonstrated a significant increase of growth inhibition of NCI-H2122 (H2122) and NCI-H441 (H441) xenograft tumors. These data informed the clinical assessment of LY2603618 in a seamless phase I/II study, which administered pemetrexed (500 mg/m(2)) and cisplatin (75 mg/m(2)) and escalating doses of LY2603618: 130-275 mg. Patients were assessed for safety, toxicity, and pharmacokinetics. In phase I, 14 patients were enrolled, and the most frequently reported adverse events included fatigue, nausea, pyrexia, neutropenia, and vomiting. No DLTs were reported at the tested doses. The systemic exposure of LY2603618 increased in a dose-dependent manner. Pharmacokinetic parameters that correlate with the maximal pharmacodynamic effect in nonclinical xenograft models were achieved at doses ≥240 mg. The pharmacokinetics of LY2603618, pemetrexed, and cisplatin were not altered when used in combination. Two patients achieved a confirmed partial response (both non-small cell lung cancer), and 8 patients had stable disease. LY2603618 administered in combination with pemetrexed and cisplatin demonstrated an acceptable safety profile. The recommended phase II dose of LY2603618 was 275 mg.

Mutations in KRas, NRas, BRaf and NF-1 that activate the Ras and mitogen-activated protein kinase (MAPK) pathway are among the most common oncogenic drivers in many cancers, including melanoma, lung, colorectal, and pancreatic cancer. Two BRaf selective inhibitors, vemurafenib and dabrafenib, have been approved for the treatment of melanoma patients harboring the BRaf V600E/K mutation. However, both compounds have been reported to promote paradoxical MAPK pathway activation in BRaf wild-type cells through induction of active Raf dimers. Therefore, they are believed to be contraindicated for treatment of cancers with BRaf wild type background. In this study, we have identified and characterized a pyrido-pyrimidine derivative inhibitor of all three Raf isoforms. A whole-cell mass spectrum-based analysis revealed that LY3009120 binds to ARaf, BRaf and CRaf isoforms with similar affinity in cells with activating mutations of BRaf or KRas, while vemurafenib or dabrafenib have little or modest CRaf activity. Additionally, LY3009120 induces BRaf-CRaf heterodimerization, but inhibits the phosphorylation of downstream MEK and ERK, indicating that it effectively inhibits the kinase activity of BRaf-CRaf heterodimer. Due to its activity against the three Raf isoforms and dimer, LY3009120 induces minimal paradoxical pathway activation in NRas or KRas mutant cells. These unique pharmacological properties of LY3009120 further distinguish it from selective BRaf inhibitors by its physiologically-relevant activities against tumor cells with NRas or KRas mutations. LY3009120 inhibits MEK phosphorylation and cell proliferation in vitro, and exhibits anti-tumor activity in multiple xenograft models carrying mutations in BRaf, NRas or KRas. LY3009120 is also active against melanoma cells with acquired resistance to vemurafenib or dabrafenib in the setting of MAPK reactivation and cyclin D1 upregulation caused by RTK/Ras activation, BRaf splice variants, or NRas Q61K mutation. Collectively, our findings identify LY3009120 as a potentially best-in-class inhibitor of three Raf isoforms and Raf dimer, with activity against tumor cells with BRaf, NRas or KRas mutations, as well as melanoma cells with acquired resistance to current BRaf therapies. These unique features support investigation of LY3009120 in clinical studies. Citation Format: Sheng-Bin Peng, James Henry, Michael Kaufman, Wei-Ping Lu, Bryan D. Smith, Subha Vogeti, Scott Wise, Youyan Zhang, Robert Van Horn, Xiaoyi Zhang, Tinggui Yin, Vipin Yadav, Lysiane Huber, Lisa Kays, Jennie Walgren, Denis McCann, Phenil Patel, Sean Buchanan, Ilaria Conti, James J. Starling, Daniel L. Flynn. Identification of LY3009120 as a pan inhibitor of Raf isoforms and dimers with minimal paradoxical activation and activities against BRaf or Ras mutant tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr DDT02-02. doi:10.1158/1538-7445.AM2014-DDT02-02

Gemcitabine (gem) is a nucleoside anticancer agent that inhibits cell cycle in S-phase and is registered clinically for the treatment of a number of solid tumors. A prodrug of gemcitabine, LY2334737, was developed for oral administration for metronomic dosing with the aim of growth inhibition of more tumor cells as they go through the cell cycle. LY is well absorbed and systemically cleaved in humans. The rate of hydrolysis is slow resulting in circulating levels of LY that are 10-fold higher than gemcitabine in plasma. Studies with cell lines and recombinant protein indicate that LY is cleaved to gemcitabine by carboxylesterase 2 (CES2). Because LY circulates in the plasma for an extended period of time, we wondered if expression of CES2 by the tumor could alter its response to the prodrug. The present study was undertaken to determine if the expression of CES2 alters cellular response to LY in vitro and in vivo. The constitutive expression of CES2 in SKOV-3 was knocked down by shRNA. A stable subclone was obtained that had CES2 expression reduced by 80%. Stable HCT-116 transfectants were prepared that overexpressed CES2. Cell lines, transfectants and knock down cells were evaluated for drug sensitivity in a cytotoxicity assay. They were also evaluated for CES2 expression by biochemical cellular assay, Western analysis, and qRT-PCR. A xenograft study was conducted employing transfected HCT-116 cells. Immunohistochemical (IHC) staining was used to evaluate cell lines and tumors for CES2 expression. LY was less cytotoxic to SKOV-3 cells when CES2 was knocked down while sensitivity to gem was unaltered. Transfection of CES2 into low CES2 endogenously expressing HCT-116 cells enhanced LY drug sensitivity with no change in gemcitabine sensitivity. Stably transfected CES2 and mock HCT-116 transfectants were grown as a xenograft. The transfectants had identical growth rates in vivo and were equally sensitive to gem treatment. IHC staining of the tumors indicated that CES2 expression was maintained throughout the growth period. CES2 expressing tumors demonstrated a statistically significant greater response to LY than mock transfectant tumors. Taken together, these studies indicate that CES2 cleaves the prodrug and tumor expression of CES2 can enhance response to treatment with LY2334737. Citation Information: Clin Cancer Res 2010;16(14 Suppl):B30.