A public-private collaboration model for clinical innovation.

Launched in May 2012 as part of the New Therapeutic Uses program, the National Center for Advancing Translational Sciences (NCATS)' National Institutes of Health (NIH)-Industry Partnerships initiative fostered collaboration between pharmaceutical companies and the biomedical research community to advance therapeutic development. Over the 10-year life of the initiative, the industry partners included: AstraZeneca; AbbVie (formerly Abbott); Bristol-Myers Squibb; Eli Lilly and Company; GlaxoSmithKline; Janssen Pharmaceutical Research & Development, L.L.C.; Pfizer; Sanofi; and Mereo (out licensed assets). The initiative provided researchers at academic medical centers with a rare opportunity to propose clinical trials to test ideas for new therapeutic uses for a selection of clinic-ready and often previously proprietary experimental pharmaceutical assets that were provided by industry partners. Here, we describe the process by which collaborations between pharmaceutical companies with viable experimental assets and academic researchers with ideas for new uses of those assets were established; and how NCATS/NIH funding supported not only phase I and II clinical trials as well as any nonclinical studies needed before testing in a new patient population, it also provided an opportunity for testing innovative outcome measures for proof-of-concept trials. Although the program did not demonstrate improved success rates for phase II clinical trials, this collaboration model leverages the strengths of each party and with a focus toward evaluating an innovative outcome measure, could be used to reduce patient burden and trial costs, and improve patient engagement.

Inhibition of 11ß-Hydroxysteroid dehydrogenase-1 with AZD4017 in patients with nonalcoholic steatohepatitis or nonalcoholic fatty liver disease: A randomized, double-blind, placebo-controlled, phase II study.

AIM: To evaluate whether short-term treatment with a selective 11ß-Hydroxysteroid dehydrogenase-1 (11ß-HSD1) inhibitor, AZD4017, would block hepatic cortisol production and thereby decrease hepatic fat in patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), with or without type 2 diabetes (T2D). MATERIALS AND METHODS: This was a randomized, double-blind, placebo-controlled, phase 2 study conducted at two sites. Key inclusion criteria were the presence of NAFLD or NASH on magnetic resonance imaging (MRI) or recent biopsy positive for NASH. Enrolled patients were randomly assigned (1:1) to AZD4017 or placebo for 12 weeks. Primary outcomes were between-group differences in mean change from baseline to week 12 in liver fat fraction (LFF) and conversion of 13 C cortisone to 13 C cortisol in the liver. RESULTS: A total of 93 patients were randomized; 85 patients completed treatment. The mean (standard deviation [SD]) change in LFF was -0.667 (5.246) and 0.139 (4.323) in the AZD4017 and placebo groups (P = 0.441). For patients with NASH and T2D, the mean (SD) change in LFF was significantly improved in the AZD4017 versus the placebo group (-1.087 [5.374] vs. 1.675 [3.318]; P = 0.033). Conversion of 13 C cortisone to 13 C cortisol was blocked in all patients in the AZD4017 group. There were no significant between-group differences (AZD4017 vs. placebo) in changes in fibrosis, weight, levels of liver enzymes or lipids, or insulin sensitivity. CONCLUSION: Although the study did not meet one of the primary outcomes, AZD4017 blocked the conversion of 13 C cortisone to 13 C cortisol in the liver in all patients who received the drug. In patients with NASH and T2D, AZD4017 improved liver steatosis versus placebo.

Effects of an Oral CRTh2 Antagonist (AZD1981) on Eosinophil Activity and Symptoms in Chronic Spontaneous Urticaria.

BACKGROUND: Approximately 50% of patients with chronic spontaneous urticaria (CSU) experience symptoms that are not fully controlled by antihistamines, indicating an unmet clinical need. OBJECTIVE: To evaluate the effects of the selective CRTh2 antagonist AZD1981 on symptoms and targeted leukocytes in adults with persistent CSU despite treatment with H1-antihistamines. METHODS: We performed a single-center, randomized, placebo-controlled study involving adult CSU subjects with symptoms despite daily antihistamines. The subjects underwent a 2-week placebo run-in and 4 weeks of double-blinded therapy with either AZD1981 40 mg TID or placebo, followed by a 2-week placebo washout. The primary objective was to assess the effect of AZD1981 on CSU signs and symptoms. Secondary objectives included the effects of AZD1981 on prostaglandin D2 (PGD2)-induced eosinophil shape change, circulating leukocyte subsets, CRTh2 expression on blood leukocytes, and total blood leukocyte histamine content. RESULTS: Twenty-eight subjects were randomized to AZD1981 or placebo, with 26 subjects completing the study. The urticaria activity scores declined during the treatment phase in both groups, and they were significantly reduced in the AZD1981 group at the end of washout. AZD1981 treatment increased circulating eosinophils and significantly impaired PGD2-mediated eosinophil shape change. CRTh2 surface expression rose significantly on blood basophils during active treatment. No serious adverse events were observed. CONCLUSIONS: This is the first study to examine the efficacy of a CRTh2 antagonist in antihistamine-refractory CSU. AZD1981 treatment was well tolerated, effectively inhibited PGD2-mediated eosinophil shape change, shifted numbers of circulating eosinophils, and reduced weekly itch scores more than hives during treatment and into washout. Further studies are needed to determine whether inhibition of the PGD2/CRTh2 pathway will be an -effective treatment for CSU.

Why Do Promising Therapies Stall in Development and How Can We Move Them Forward?

There are many reasons that molecules fail to progress to market and various principles of risk-benefit decisions that can help drive the molecule through development. This symposium included discussions on global strategies involved in pushing promising molecules to market, what to do when a molecule stalls in its progress to market, and options for rescuing the molecule and pushing it forward again. Innovative partnerships that bring stalled drugs back into clinical development were also addressed. A regulatory perspective on common reasons for a molecule to fail in its forward progress was presented. In addition, situations arise when a third-party advisory committee can provide input to help overcome issues identified by a regulatory agency. Using examples from the private and public domain, presentations centered on how to repurpose a molecule and when more science is needed.

Pioneering government-sponsored drug repositioning collaborations: progress and learning.

A new model for translational research and drug repositioning has recently been established based on three-way partnerships between public funders, the pharmaceutical industry and academic investigators. Through two pioneering initiatives - one involving the Medical Research Council in the United Kingdom and one involving the National Center for Advancing Translational Sciences of the National Institutes of Health in the United States - new investigations of highly characterized investigational compounds have been funded and are leading to the exploration of known mechanisms in new disease areas. This model has been extended beyond these first two initiatives. Here, we discuss the progress to date and the unique requirements and challenges for this model.

Targeting tumor-infiltrating macrophages decreases tumor-initiating cells, relieves immunosuppression, and improves chemotherapeutic responses.

Tumor-infiltrating immune cells can promote chemoresistance and metastatic spread in aggressive tumors. Consequently, the type and quality of immune responses present in the neoplastic stroma are highly predictive of patient outcome in several cancer types. In addition to host immune responses, intrinsic tumor cell activities that mimic stem cell properties have been linked to chemoresistance, metastatic dissemination, and the induction of immune suppression. Cancer stem cells are far from a static cell population; rather, their presence seems to be controlled by highly dynamic processes that are dependent on cues from the tumor stroma. However, the impact immune responses have on tumor stem cell differentiation or expansion is not well understood. In this study, we show that targeting tumor-infiltrating macrophages (TAM) and inflammatory monocytes by inhibiting either the myeloid cell receptors colony-stimulating factor-1 receptor (CSF1R) or chemokine (C-C motif) receptor 2 (CCR2) decreases the number of tumor-initiating cells (TIC) in pancreatic tumors. Targeting CCR2 or CSF1R improves chemotherapeutic efficacy, inhibits metastasis, and increases antitumor T-cell responses. Tumor-educated macrophages also directly enhanced the tumor-initiating capacity of pancreatic tumor cells by activating the transcription factor STAT3, thereby facilitating macrophage-mediated suppression of CD8(+) T lymphocytes. Together, our findings show how targeting TAMs can effectively overcome therapeutic resistance mediated by TICs.

Can the flow of medicines be improved? Fundamental pharmacokinetic and pharmacological principles toward improving Phase II survival.

In an effort to uncover systematic learnings that can be applied to improve compound survival, an analysis was performed on data from Phase II decisions for 44 programs at Pfizer. It was found that not only were the majority of failures caused by lack of efficacy but also that, in a large number of cases (43%), it was not possible to conclude whether the mechanism had been tested adequately. A key finding was that an integrated understanding of the fundamental pharmacokinetic/pharmacodynamic principles of exposure at the site of action, target binding and expression of functional pharmacological activity (termed together as the 'three Pillars of survival') all determine the likelihood of candidate survival in Phase II trials and improve the chance of progression to Phase III.

Discovery of an Oral Potent Selective Inhibitor of Hematopoietic Prostaglandin D Synthase (HPGDS).

Hematopoietic prostaglandin D synthase (HPGDS) is primarly expressed in mast cells, antigen-presenting cells, and Th-2 cells. HPGDS converts PGH2 into PGD2, a mediator thought to play a pivotal role in airway allergy and inflammatory processes. In this letter, we report the discovery of an orally potent and selective inhibitor of HPGDS that reduces the antigen-induced response in allergic sheep.

Nonpeptide luteinizing hormone-releasing hormone antagonists derived from erythromycin A: design, synthesis, and biological activity of cladinose replacement analogues.

The design and synthesis of a series of 11,12-cyclic carbamate derivatives of 6-O-methylerythromycin A that are novel, nonpeptide LHRH antagonists, is described. The macrolide antagonist 1, discovered during a screen of our chemical repository, was compared to a macrocyclic peptide antagonist 2 using molecular modeling, thus providing a model for the design of more potent antagonists. Medicinal chemistry efforts to find a replacement for cladinose at position 3 of the erythronolide core provided a series of oxazolidinone carbamates that were equally as active as the cladinose-containing parent macrolides. The descladinose LHRH antagonist 14 has 1-2 nM affinity for both rat and human LHRH receptors and is a potent inhibitor of LH release (pA2 = 8.76) in vitro. In vivo, 14 was found to produce a dose-dependent suppression of LH in male castrate rats via both i.v. and p.o. dosing.

A method for determining whether hypotension caused by novel compounds in preclinical development results from histamine release.

INTRODUCTION: Many therapeutic agents stimulate histamine release from mast cells, which results in a decrease in blood pressure. The purpose of this study is to establish a method to determine if the mechanism of action, or one of the mechanisms, of hypotensive compounds is related to the release of histamine. The method was developed using a novel hypotensive compound, SC-372. METHODS: In Inactin anesthetized rats, after intravenous administration of SC-372 (0.3-7 mg/kg), the 2 and 7 mg/kg resulted in a dose-dependent decrease in blood pressure. Histamine (0.1 and 1 mg/kg) was injected intravenously to establish whether histamine release was the mechanism of action for the hypotension induced by SC-372. Compound 48/80 (0.1 mg/kg, promotes histamine release) and Cromolyn (1 mg/kg/min, [5 min], prevents histamine release from mast cells) were characterized and used intravenously in combination with/or compared to SC-372. RESULTS: Histamine resulted in a decrease in blood pressure that was unaffected by Cromolyn (1 mg/kg). Administration of Compound 48/80 resulted in a rapid reduction of systemic blood pressure. Intravenous infusion of Cromolyn prior to the injection of Compound 48/80 significantly attentuated the hypotensive response and the increase in histamine levels in the plasma. Intravenous administration of SC-372 resulted in a rapid reduction in blood pressure with a profile similar to that of Compound 48/80. When the rats were treated with Cromolyn prior to the administration of SC-372, both the blood pressure and plasma histamine levels were maintained at their pretreatment control levels. DISCUSSION: These data indicate that Compound 48/80 and Cromolyn can be used in rats to screen for histamine release-dependent drug-induced hypotension and suggest that the rapid decrease in blood pressure caused by SC-372 may result from histamine release from mast cells.

Preischemic and postischemic administration of AEOL10113 reduces infarct size in a rat model of myocardial ischemia and reperfusion.

Reactive oxygen species (ROS) have been implicated as important mediators of cellular damage during ischemia/reperfusion. AEOL10113 is a low-molecular-weight superoxide dismutase mimetic that has dismutase activity against ROS. The objective of this study was to test the cardioprotective efficacy of postischemic administration of AEOL10113 in a rat model of left ventricular ischemia and reperfusion. Left ventricular infarction was produced by 25 min of left coronary artery occlusion followed by 3 h of reperfusion. Infarct size (IS) is reported as IS/area at risk (AAR). The control group had an IS/AAR of 67.5 +/- 2.6%. Postischemic administration of AEOL10113 beginning 5 min prior to reperfusion at doses of 0.03, 0.1, and 0.3 mg/kg resulted in an IS/AAR of 69.3 +/- 3.4%, 57.8 +/- 3.3% (P < 0.05), and 55.0 +/- 2.9% (P < 0.05), respectively. Preischemic administration of AEOL10113 beginning 5 min prior to occlusion at a dose of 0.3 mg/kg resulted in an IS/AAR of 44.2 +/- 5.9% (P < 0.0125). AAR as a percentage of the left ventricle and rate-pressure product were unaffected by any dose tested. The data from this study demonstrate that pre- and postischemic administration of AEOL10113 reduces IS in a rat model of myocardial ischemia and reperfusion.

Transforming growth factor beta mimetics: discovery of 7-[4-(4-cyanophenyl)phenoxy]-heptanohydroxamic acid, a biaryl hydroxamate inhibitor of histone deacetylase.

Transforming growth factor beta (TGF-beta) is a multifunctional protein that has been shown to possess potent growth-inhibitory activity. To identify small molecular weight compounds with TGF-beta-like activities, high throughput screening was performed using mink lung epithelial cells stably transfected with a TGF-beta-responsive plasminogen activator inhibitor 1 promoter/luciferase construct. Biaryl hydroxamate compounds were identified that demonstrated TGF-beta-like activities. 7-[4-(4-cyanophenyl)phenoxy]-heptanohydroxamic acid (A-161906) demonstrated complete TGF-beta-like agonist activity in the plasminogen activator inhibitor 1/luciferase construct. A-161906 inhibited the proliferation of multiple cell lines in a concentration-dependent manner. Cells were growth arrested at the G1-S checkpoint similar to TGF-beta. Consistent with the G1-S arrest, A-161906 induced the expression of the cyclin-dependent kinase inhibitor p21waf1/cip1. A-161906 produced many cellular effects similar to that of TGF-beta but did not displace labeled TGF-beta from its receptors. Cells with mutations in either of the TGF-beta receptors I or II were growth-arrested by A-161906. Therefore, the site of action of A-161906 appears to be distal to the receptors and possibly involved with the signaling events controlled by TGF-beta. The TGF-beta mimetic effect of A-161906 can be partially, if not entirely, explained by its activity as a histone deacetylase (HDAC) inhibitor. A-161906 demonstrated potent HDAC-inhibitory activity (IC50 = 9 nM). A-161906 is a novel small molecular weight compound (< 400 MW) having TGF-beta mimetic activity as a result of its potent HDAC-inhibitory activity. These results and those of others demonstrate the importance of HDACs in regulation of the TGF-beta signaling pathway(s).

Hypertension induced by blockade of ET(B) receptors in conscious nonhuman primates: role of ET(A) receptors.

The role of endothelin-B (ET(B)) receptors in circulatory homeostasis is ambiguous, reflecting vasodilator and constrictor effects ascribed to the receptor and diuretic and natriuretic responses that could oppose the hypertensive effects of ET excess. With the use of conscious, telemetry-instrumented cynomolgus monkeys, we characterized the hypertension produced by ET(B) blockade and the role of ET(A) receptors in mediating this response. Mean arterial pressure (MAP) and heart rate (HR) were measured 24 h/day for 24 days under control conditions and during administration of the ET(B)-selective antagonist A-192621 (0.1, 1.0, and 10 mg/kg bid, 4 days/dose) followed by coadministration of the ET(A) antagonist atrasentan (5 mg/kg bid) + A-192621 (10 mg/kg bid) for another 4 days. High-dose ET(B) blockade increased MAP from 79 +/- 3 (control) to 87 +/- 3 and 89 +/- 3 mmHg on the first and fourth day, respectively; HR was unchanged, and plasma ET-1 concentration increased from 2.1 +/- 0.3 pg/ml (control) to 7.24 +/- 0.99 and 11.03 +/- 2.37 pg/ml. Atrasentan + A-192621 (10 mg/kg) decreased MAP from hypertensive levels (89 +/- 3) to 75 +/- 2 and 71 +/- 4 mmHg on the first and fourth day, respectively; plasma ET-1 and HR increased to 26.64 +/- 3.72 and 28.65 +/- 2.89 pg/ml and 113 +/- 5 (control) to 132 +/- 5 and 133 +/- 7 beats/min. Thus systemic ET(B) blockade produces a sustained hypertension in conscious nonhuman primates, which is mediated by ET(A) receptors. These data suggest an importance clearance function for ET(B) receptors, one that influences arterial pressure homeostasis indirectly by reducing plasma ET-1 levels and minimizing ET(A) activation.

Evaluation of tissue perfusion in a rat model of hind-limb muscle ischemia using dynamic contrast-enhanced magnetic resonance imaging.

PURPOSE: To evaluate the feasibility of using dynamic contrast-enhanced magnetic resonance imaging (MRI) for assessment of muscle perfusion in a rat model of hind-limb ischemia. MATERIALS AND METHODS: The acute alteration and chronic recovery in muscle perfusion and perfusion reserve after femoral artery ligation were quantified using the maximum Gd-DTPA uptake rate obtained by a T(1)-weighted gradient-recalled echo sequence. Radionuclide-labeled microsphere blood flow measurements were performed for comparison with the MR perfusion measurement on a separate set of animals. RESULTS: After femoral artery ligation, a significant reduction in resting muscle perfusion was only observed at 1 hour post-ligation during the 28-day follow-up period. Muscle perfusion reserve was severely diminished following the ligation. Despite significant recovery over time, perfusion reserve to the ligated limb reached only 63% of the perfusion capacity in the unaffected limb by 42 days post ligation. A strong correlation (r = 0.86) between MR perfusion and microsphere blood flow measurements was observed for evaluation of relative changes in muscle perfusion. CONCLUSION: Dynamic contrast-enhanced MRI with Gd-DTPA is useful to assess time-dependent changes in muscle perfusion and perfusion reserve in this hind-limb ischemia model.

Bimoclomol elevates heat shock protein 70 and cytoprotects rat neonatal cardiomyocytes.

Bimoclomol is a new compound that improves cell survival under experimental stress conditions partly by increasing intracellular heat shock proteins (HSPs). HSPs, especially HSP70, play a cytoprotective role in the rat heart. Rat neonatal cardiomyocytes were used to determine the ability of bimoclomol to induce HSP70 and affect cell survival across a broad concentration range (0.01-100 microM). Bimoclomol significantly elevated HSP70 levels at concentrations ranging from 0.01 to 10 microM, depending on the time of exposure. Pretreatment with bimoclomol for 24 h significantly increased survival of cells. There was a significant correlation between the increased levels of HSP70 and the increase in cell survival as a result of the treatment with bimoclomol. In conclusion, bimoclomol improved cell survival in rat neonatal cardiomyocytes, in part, by increasing the levels of HSP70. This cytoprotection began at the relatively low concentration of 0.1 microM, which is a concentration that can be achieved clinically.

Oral bimoclomol elevates heat shock protein 70 and reduces myocardial infarct size in rats.

Bimoclomol has been shown to increase an inducible member of the heat shock protein 70 family (HSP70) and cytoprotect in vitro. Here, we addressed whether oral pretreatment of rats with bimoclomol could elevate myocardial HSP70 and reduce infarct size in a rat model of ischemia and reperfusion. Rats were pretreated with bimoclomol at 3, 6 or 18 h or with 42 degrees thermal stress 24 h before ischemia. Infarct size was significantly decreased 6 h after oral administration of bimoclomol and 24 h after thermal stress. Left ventricles from a separate group of rats were examined for HSP70 levels. Western blots showed a significant increase in HSP70 6 h after oral administration of bimoclomol and 24 h after thermal stress. There was a significant correlation (P<0.05) between HSP70 induction and infarct size reduction, whether produced by thermal stress or oral administration of bimoclomol. Thus, bimoclomol can increase HSP70 and reduce infarct size in a rat model of ischemia and reperfusion.