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Salt forms of pharmaceutical compounds can have unique pharmacokinetic and toxicity properties. MDV1634 was evaluated for neurology indication and also demonstrated blood pressure (BP)-lowering effects in nonclinical studies. During the chemistry manufacturing campaign, 2 salt forms, dihydrochloride (2HCl) and maleate (MAL), which improved chemical stability and water solubility of the free base were identified. MDV1634.MAL showed better chemical attributes and was evaluated in toxicology studies for further development. A 28-day oral toxicity study in dogs with MDV1634.MAL demonstrated partially reversible renal toxicity. Although MAL salt is generally regarded as safe, renal toxicity is sometimes observed in rats and dogs. To evaluate contribution of each salt form to renal toxicity and BP lowering, an additional 28-day study was conducted with MDV1634.2HCL and MDV1634.MAL, which included toxicokinetics, continuous BP measurement in a subset of dogs, and sensitive urinary biomarker evaluation for temporal monitorability and reversibility of potential renal findings. In the repeat study, both salt forms showed similar exposures during the dosing period, but renal tubular toxicity was observed only with MDV1634.MAL and not with MDV1634.2HCl. The renal findings with MDV1634.MAL included early urinary biomarker changes (increase in albumin, clusterin, β2 microglobulin, and neutrophil gelatinase-associated lipocalin); elevations in serum blood urea nitrogen and creatinine; and microscopic findings of partially reversible tubular basophilia, single cell necrosis, pigmentation, and mineralization. The renal findings in contrast to the BP findings were MAL-specific and considered not related to MDV1634, thereby under scoring the importance of salt forms in pharmaceutical development.

Enzalutamide and apalutamide are two androgen receptor inhibitors approved for the treatment of castration-resistant prostate cancer (CRPC) and nonmetastatic castration-resistant prostate cancer (nmCRPC), respectively. Apalutamide is associated with an increased incidence of skin rash above the placebo groups in the SPARTAN trial in nmCRPC and in the TITAN trial in metastatic castration-sensitive prostate cancer patients. On the contrary, the rate of skin rash across all clinical trials (including PROSPER [nmCRPC]) for enzalutamide is similar to the placebo. We hypothesized that the apalutamide-associated increased skin rash in patients could be linked to a structural difference. The 2-cyanophenyl and dimethyl moieties in enzalutamide are substituted in apalutamide with 2-cyanopyridine and cyclobutyl, respectively. In our evaluations, the 2-cyanopyridine moiety of apalutamide was chemically reactive with the thiol nucleophile glutathione, resulting in rearranged thiazoline products. Radiolabeled apalutamide, but not radiolabeled enzalutamide, was shown to react with mouse and human plasma proteins. Thiol nucleophiles decreased the extent of covalent binding to the model protein bovine serum albumin, whereas amine and alcohol nucleophiles had no effect, suggesting reactivity with cysteine of proteins. Subcutaneous administration of apalutamide dose dependently increased lymphocyte cellularity in draining lymph nodes in a mouse drug allergy model (MDAM). Enzalutamide, and its known analogue RD162 in which the cyanophenyl was retained but the dimethyl was replaced by cyclobutyl, demonstrated substantially less covalent binding activity and negative results in the MDAM assay. Collectively, these data support the hypothesis that the 2-cyanopyridine moiety in apalutamide may react with cysteine in proteins forming haptens, which may trigger an immune response, as indicated by the activity of apalutamide in the MDAM assay, which in turn may be leading to increased potential for skin rash versus placebo in patients in the SPARTAN and TITAN clinical trials.

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued.

Pulmonary arterial hypertension (PAH) results from occlusion or vasoconstriction of pulmonary vessels, leading to progressive right ventricular failure. Dasatinib, a BCR-ABL1 tyrosine kinase inhibitor (TKI) approved for the treatment of chronic myelogenous leukemia, has been associated with PAH. In contrast, the BCR-ABL1 TKI imatinib has demonstrated anti-vasoproliferative properties and has been investigated as a potential treatment for PAH. Here we describe studies evaluating the effects of dasatinib and imatinib on cardiovascular and pulmonary functions to understand the reported differential consequences of the two TKIs in a clinical setting. The direct effects of dasatinib and imatinib were explored in vivo to investigate possible mechanisms of dasatinib-induced PAH. In addition, effects of dasatinib and imatinib on PAH-related mediators were evaluated in vitro. In rats, both TKIs increased plasma nitric oxide (NO), did not induce PAH-related structural or molecular changes in PA or lungs, and did not alter hemodynamic lung function compared with positive controls. Similarly, in the pulmonary artery endothelial cells and smooth muscle cells co-culture model, imatinib and dasatinib increased NO and decreased endothelin-1 protein and mRNA. The results of these studies indicated that dasatinib did not induce physiological changes or molecular signatures consistent with PAH when compared to positive controls. Instead, dasatinib induced changes consistent with imatinib. Both dasatinib and imatinib induced biochemical and structural changes consistent with a protective effect for PAH. These data suggest that other factors of unclear etiology contributed to the development of PAH in patients treated with dasatinib.

The B7-family molecule CD86, expressed on the surface of pulmonary and thoracic lymph node antigen-presenting cells, delivers essential costimulatory signals for T-cell activation in response to inhaled allergens. CD86-CD28 signaling is involved in priming allergen-specific T cells, but it is unclear whether these interactions play a role in coordinating memory T-helper 2 cell responses. In the ovalbumin (OVA)-induced mouse model of asthma, administration of CD86-specific antibody before systemic sensitization suppresses inhaled OVA-induced pulmonary inflammation and airway hyper-responsiveness (AHR). In previously OVA-sensitized mice, systemic and intranasal coadministration of CD86 antibody is required to produce these effects. To directly assess the importance of pulmonary CD86 expression in secondary immune responses to inhaled allergens, mice were sensitized and locally challenged with nebulized OVA before treatment with an inhaled aerosolized CD86 antisense oligonucleotide (ASO). CD86 ASO treatment suppressed OVA-induced up-regulation of CD86 protein expression on pulmonary dendritic cells and macrophages as well as on recruited eosinophils. Suppression of CD86 protein expression correlated with decreased methacholine-induced AHR, airway inflammation, and mucus production following rechallenge with inhaled OVA. CD86 ASO treatment reduced BAL eotaxin levels, but it did not reduce CD86 protein on cells in the draining lymph nodes of the lung, and it had no effect on serum IgE levels, suggesting a local and not a systemic effect. These results demonstrate that CD86 expression on pulmonary antigen-presenting cells plays a vital role in regulating pulmonary secondary immune responses and suggest that treatment with an inhaled CD86 ASO may have utility in asthma and other chronic inflammatory lung conditions.

Glucocorticoids, such as dexametha- sone (Dex), are used clinically in the treatment of various inflammatory diseases. Dex acts by inhib- iting the expression of inflammatory mediators, such as tumor necrosis factor (TNF-) and monocyte chemoattractant protein-1 (MCP-1). It is surprising that Dex enhances bacterial lipopoly- saccharide (LPS) induction of tissue factor (TF) expression in human monocytic cells. TF is a trans- membrane glycoprotein that activates the coagula- tion protease cascade. In this study, we analyze the mechanism by which Dex enhances LPS-induced TF expression in human monocytic cells. We found that Dex reduced LPS-induced TF gene transcrip- tion but increased the stability of TF mRNA. Dex decreased the stability of MCP-1 mRNA and did not affect TNF- mRNA stability. Finally, we showed that Dex increased the stability of a tran- script consisting of the final 297 nucleotides of the TF mRNA in in vitro decay assays. This region contains AU-rich elements that regulate mRNA sta- bility and may mediate the Dex response. There- fore, despite an inhibition of TF gene transcrip- tion, Dex enhances TF expression in human mono- cytic cells by increasing the stability of TF mRNA. J. Leukoc. Biol. 76: 145-151; 2004.

Monocyte activation and adhesion to the endothelium play important roles in inflammatory and cardiovascular diseases. These processes are further aggravated by hyperglycemia, leading to cardiovascular complications in diabetes. We have previously shown that high glucose (HG) treatment activates monocytes and induces the expression of tumor necrosis factor (TNF)-α via oxidant stress and nuclear factor-kB transcription factor. To determine the effects of HG on the expression of other inflammatory genes, in the present study, HG-induced gene profiling was performed in THP-1 monocytes using cytokine gene arrays containing 375 known genes. HG treatment upregulated the expression of 41 genes and downregulated 15 genes that included chemokines, cytokines, chemokines receptors, adhesion molecules, and integrins. RT-PCR analysis further confirmed that HG significantly increased the expression of monocyte chemoattractant protein-1 (MCP-1), TNF-α, β2-integrin, interleukin-1β, and others. HG treatment increased transcription of the MCP-1 gene, MCP-1 protein levels, and adhesion of THP-1 cells to endothelial cells. HG-induced MCP-1 mRNA expression and monocyte adhesion were blocked by specific inhibitors of oxidant stress, protein kinase C, ERK1/2, and p38 mitogen-activated protein kinases. These results show for the first time that multiple inflammatory cytokines and chemokines relevant to the pathogenesis of diabetes complications are induced by HG via key signaling pathways.

Monocytes and macrophages express cytokines and procoagulant molecules in various inflammatory diseases. In sepsis, lipopolysaccharide (LPS) from Gram-negative bacteria induces tumor necrosis factor-alpha (TNF-alpha) and tissue factor (TF) in monocytic cells via the activation of the transcription factors Egr-1, AP-1, and nuclear factor-kappa B. However, the signaling pathways that negatively regulate LPS-induced TNF-alpha and TF expression in monocytic cells are currently unknown. We report that inhibition of the phosphatidylinositol 3-kinase (PI3K)-Akt pathway enhances LPS-induced activation of the mitogen-activated protein kinase pathways (ERK1/2, p38, and JNK) and the downstream targets AP-1 and Egr-1. In addition, inhibition of PI3K-Akt enhanced LPS-induced nuclear translocation of nuclear factor-kappa B and prevented Akt-dependent inactivation of glycogen synthase kinase-beta, which increased the transactivational activity of p65. We propose that the activation of the PI3K-Akt pathway in human monocytes limits the LPS induction of TNF-alpha and TF expression. Our study provides new insight into the inhibitory mechanism by which the PI3K-Akt pathway ensures transient expression of these potent inflammatory mediators.

Increased oxidative stress has been reported in vivo in the diabetic state via the production of reactive oxygen species (ROS). Such stress is bound to play a key role on activation of circulating monocytes, leading to the accelerated atherosclerosis observed in diabetics. However the exact molecular mechanisms of monocyte activation by high glucose is currently unclear. Here, we demonstrate that chronic high glucose (CHG) causes a dramatic increase in the release of the inflammatory cytokine tumor necrosis factor alpha (TNFalpha), at least in part through enhanced TNFalpha mRNA transcription, mediated by ROS via activation of transcription factors nuclear factor kappaB (NF-kappaB) and activating protein-1 (AP-1). TNFalpha accumulation in the conditioned media was increased 10-fold and mRNA levels were increased 11.5-fold by CHG. The following observations supported that both NF-kappaB and AP-1 mediated enhanced TNFalpha transcription by CHG: 1) A 295-base pair fragment of the proximal TNFalpha promoter containing NF-kappaB and AP-1 sites reproduced the effects of CHG on TNFalpha transcription in a luciferase reporter assay, 2) mutational analyses of both NF-kappaB and the AP-1 sites abrogated 90% of the luciferase activity, 3) gel-shift analysis using the binding sites showed activation of NF-kappaB and AP-1 in CHG nuclear extracts, and 4) Western blot analyses demonstrated elevated nuclear levels of p65 and p50 and decreased cytosolic levels of IkappaBalpha in CHG-treated monocytes. That ROS acted as a key intermediate in the CHG pathway was supported by the following evidence: 1) increased superoxide levels similar to those observed with PMA or TNFalpha, 2) increased phosphorylation of stress-responsive mitogen-activated protein kinases p38 and JNK-1, 3) counteraction of the effects of CHG on TNFalpha production, the 295TNFluc reporter activity, activation of NF-kappaB, and repression of IkappaBalpha by antioxidants and p38 mitogen-activated protein kinase inhibitors. The study suggests that ROS function as key components in the regulatory pathway progressing from elevated glucose to monocyte activation.

Drug-induced kidney injury (DIKI) results in attrition during drug development; new DIKI urinary biomarkers offer potential to detect and monitor DIKI progression and regression, but frequently only in rats. The triple reuptake inhibitor (TRI) PRC200-SS represents a new class of antidepressants that elevate synaptic levels of serotonin, norepinephrine, and dopamine and is expected to produce more rapid onset and better antidepressant efficacy than single or dual inhibitors. Although preclinical studies and recent clinical trials lend support to this concept of superior efficacy for TRIs, there is little information on the safety profile of this class of compounds. Using histopathology and DIKI biomarkers, in single- and repeat dose toxicological studies in cynomolgus monkeys, PRC200-SS demonstrated dose-proportional kidney toxicity. Characterization of the histopathological lesions, using a combination of immunohistochemistry (IHC) and urinary biomarker analysis, indicated that the compound is a distal tubule and collecting duct toxicant. Segment specificity for the lesions was shown using a newly developed triple IHC combination method with antibodies against calbindin D28, aquaporin 2, and aquaporin 1. Urinary biomarker analyses, using multiplex immunoassays, confirmed a dose-proportional increase in the excretion of calbindin D28 and clusterin in compound-treated monkeys with levels returning to baseline during the drug-free recovery period. These results constitute the validation of distal nephron DIKI biomarkers in the cynomolgus monkey and demonstrate the utility of calbindin D28 and clusterin to monitor the progression of distal nephron DIKI, representing potential early biomarkers of DIKI for the clinic.

Optimization of a screening hit from uHTS led to the discovery of TGR5 agonist 32, which was shown to have activity in a rodent model for diabetes.

The gene encoding the highly antigenic 28K (pp28) tegument phosphoprotein of human cytomegalovirus (HCMV) was expressed in insect cells utilizing a recombinant baculovirus. The mature intracellular form of the recombinant-derived pp28 had mobility on SDS-polyacrylamide gels similar to that of native pp28 from HCMV strain Towne-infected human foreskin fibroblasts (HFFs). In vitro labelling of recombinant Autographa californica nuclear polyhedrosis virus-infected Spodoptera frugiperda cells or of HCMV-infected HFFs with [32P]orthophosphate followed by immunoprecipitation showed that both the insect cell-derived and HCMV strain Towne-infected fibroblast-derived pp28 were phosphorylated. The mobility of pp28 derived from these two sources as well as from extracellular HCMV virions indicated the existence of multiple charged forms of the protein, and a difference in the relative amounts of these forms expressed in HCMV-infected HFFs and recombinant baculovirus-infected insect cells. The recombinant pp28 expressed in insect cells was readily and specifically recognized by antibodies to native pp28, including HCMV-seropositive human serum, and was used in an ELISA to screen human sera for seropositivity.

Diabetic nephropathy (DN) remains a major complication in both type 1 and type 2 diabetes. Systemic administration of antitransforming growth factor-beta (TGF-beta) antibody has shown some promise in mouse models of DN. However, chronic blockade of the multifunctional TGB-beta could be problematic. Several downstream effects of TGF-beta are mediated by connective tissue growth factor (CTGF), which is up-regulated in several renal cells and secreted in the urine in the diabetic state. Using murine models of DN (type 1 and type 2) and a CTGF antisense oligonucleotide (ASO) of novel chimeric chemistry, we evaluated the specific role of this target in DN. In the type 1 model of DN, C57BL6 mice were made diabetic using streptozotocin injections and hyperglycemic animals were treated with CTGF ASOs (20 mg/kg/2 qw) for 4 months. ASO, but not mismatch control oligonucleotide, -treated animals showed significant reduction in target CTGF expression in the kidney with a concomitant decrease in proteinuria and albuminuria. Treatment with the CTGF ASO for 8 wk reduced serum creatinine and attenuated urinary albuminuria and proteinuria in diabetic db/db mice, a model of type 2 DN. The ASO also reduced expression of genes involved in matrix expansion such as fibronectin and collagen (I and IV) and an inhibitor of matrix degradation, PAI-1, in the renal cortex, contributing to significant reversal of mesangial expansion in both models of DN. Pathway analyses demonstrated that diabetes-induced phosphorylation of p38 MAPK and its downstream target CREB was also inhibited by the ASO. Our results strongly suggest that blocking CTGF using a chimeric ASO holds substantial promise for the treatment of DN.

The Th2 cytokines IL-4 and IL-13 mediate allergic pulmonary inflammation and airways hyperreactivity (AHR) in asthma models through signaling dependent upon the IL-4 receptor-alpha chain (IL-4Ralpha). IL-13 has been further implicated in the overproduction of mucus by the airway epithelium and in lung remodeling that commonly accompanies chronic inflammation. IL-4Ralpha-deficient mice are resistant to allergen-induced asthma, highlighting the therapeutic promise of selective molecular inhibitors of IL-4Ralpha. We designed a chemically modified IL-4Ralpha antisense oligonucleotide (IL-4Ralpha ASO) that specifically inhibits IL-4Ralpha protein expression in lung eosinophils, macrophages, dendritic cells, and airway epithelium after inhalation in allergen-challenged mice. Inhalation of IL-4Ralpha ASO attenuated allergen-induced AHR, suppressed airway eosinophilia and neutrophilia, and inhibited production of airway Th2 cytokines and chemokines in previously allergen-primed and -challenged mice. Histologic analysis of lungs from these animals demonstrated reduced goblet cell metaplasia and mucus staining that correlated with inhibition of Muc5AC gene expression in lung tissue. Therapeutic administration of inhaled IL-4Ralpha ASO in chronically allergen-challenged mice produced a spectrum of anti-inflammatory activity similar to that of systemically administered Dexamethasone with the added benefit of reduced airway neutrophilia. These data support the potential utility of a dual IL-4 and IL-13 oligonucleotide inhibitor in allergy/asthma, and suggest that local inhibition of IL-4Ralpha in the lung is sufficient to suppress allergen-induced pulmonary inflammation and AHR.

In septic shock, tissue factor (TF) activates blood coagulation, and cytokines and chemokines orchestrate an inflammatory response. In this study, the role of Egr-1 in lipopolysaccharide (LPS) induction of TF and inflammatory mediators in vivo was evaluated using Egr-1+/+ and Egr-1−/− mice. Administration of LPS transiently increased the steady-state levels of Egr-1 mRNA in the kidneys and lungs of Egr-1+/+ mice with maximal induction at one hour. Egr-1 was expressed in epithelial cells in the kidneys and lungs in untreated and LPS-treated mice. LPS induction of monocyte chemoattractant protein mRNA in the kidneys and lungs of Egr-1−/− mice was not affected at 3 hours, but its expression was significantly reduced at 8 hours compared with the expression observed in Egr-1+/+ mice. Similarly, LPS induction of TF mRNA expression in the kidneys and lungs at 8 hours was reduced in Egr-1−/− mice. However, Egr-1 deficiency did not affect plasma levels of tumor necrosis factor α in endotoxemic mice. Moreover, Egr-1+/+ and Egr-1−/− mice exhibited similar survival times in a model of acute endotoxemia. These data indicate that Egr-1 does not contribute to the early inflammatory response in the kidneys and lungs or the early systemic inflammatory response in endotoxemic mice. However, Egr-1 does contribute to the sustained expression of inflammatory mediators and to the maximal expression of TF at 8 hours in the kidneys and lungs.

Pulmonary arterial hypertension (PAH), defined by increase in mean pulmonary arterial pressure (PAP), results from occlusion or vasoconstriction of the pulmonary veins and can lead to progressive right ventricular failure. The tyrosine kinase inhibitor (TKI) imatinib, indicated for chronic myelogenous leukemia (CML) is being investigated as a potential treatment for PAH, due to its anti-vasoproliferative properties. However, the TKI dasatinib also used for CML is associated with PAH in a small percentage of heavily pre-treated patients although partial or complete reversibility is seen after discontinuation of treatment. Despite the different kinase profiles, studies in rat models of PAH have shown that both TKIs are equally efficacious in reversing functional and structural PAH-related changes. Therefore, nonclinical in vivo (SD rat) and in vitro (human pulmonary artery endothelial cells/smooth muscle cells [hPAEC/hPASM) studies evaluating direct effects of the two TKIs were conducted to understand the potential mechanistic differences for the apparently different clinical effect. The in vivo study explored direct effects of vehicle (80 mM citric acid; control), clinically relevant doses of imatinib and dasatinib (30 or 8 mg/kg/day, oral) and monocrotaline (single i.p. dose, 70 mg/kg; positive control) on PAH-related pulmonary changes in rats (1-month treatment). Monocrotaline reduced nitric oxide (NO; vasodilation) and increased endothelin-1 (ET-1; vasoconstriction) levels in plasma, induced structural changes (perivascular inflammation, EC injury and SMC proliferation) in PA and lungs, and increased (2-5× control) systolic and diastolic PAP and right ventricular pressure. In contrast, both imatinib and dasatinib increased NO in plasma (2.5×), did not any induce PAH-related structural changes (PA or lungs) and did not alter hemodynamic function compared to controls. The in vitro hPAEC/PASM co-culture model demonstrated that imatinib and dasatinib at clinically relevant (Cmax) concentrations increased NO and decreased ET-1 protein and mRNA. Our results demonstrate that dasatinib, as imatinib, does not have the potential to directly induce PAH-related changes in vivo or in vitro. In addition, both molecules induce biochemical changes in vivo and in vitro consistent with a protective effect on PAP. Citation Format: Mausumee Guha, James Hennan, Julia Li, Damir Simic, Jochen Woiche, Bethany Baumgart, Thomas Sanderson, Michael Graziano, Roderick Bunch. In vitro and in vivo evaluation of dasatinib and imatinib on physiological parameters of pulmonary arterial hypertension . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2426. doi:10.1158/1538-7445.AM2013-2426 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.