Water-Soluble Progesterone Analogues Are Effective, Injectable Treatments in Animal Models of Traumatic Brain Injury

After more than 30 years of research and 30 failed clinical trials with as many different treatments, progesterone is the first agent to demonstrate robust clinical efficacy as a treatment for traumatic brain injuries. It is currently being investigated in two, independent phase III clinical trials in hospital settings; however, it presents a formidable solubility challenge that has so far prevented the identification of a formulation that would be suitable for emergency field response use or battlefield situations. Accordingly, we have designed and tested a novel series of water-soluble analogues that address this critical need. We report here the synthesis of C-20 oxime conjugates of progesterone as therapeutic agents for traumatic brain injuries with comparable efficacy in animal models of traumatic brain injury and improved solubility and pharmacokinetic profiles. Pharmacodynamic analysis reveals that a nonprogesterone steroidal analogue may be primarily responsible for the observed activity

Non-nucleoside Inhibitors of the Measles Virus RNA-Dependent RNA Polymerase: Synthesis, Structure–Activity Relationships, and Pharmacokinetics

The measles virus (MeV), a member of the paramyxovirus family, is an important cause of pediatric morbidity and mortality worldwide. In an effort to provide therapeutic treatments for improved measles management, we previously identified a small, non-nucleoside organic inhibitor of the viral RNA-dependent RNA polymerase by means of high-throughput screening. Subsequent structure–activity relationship (SAR) studies around the corresponding pyrazole carboxamide scaffold led to the discovery of <b>2</b> (AS-136a), a first generation lead with low nanomolar potency against life MeV and attractive physical properties suitable for development. However, its poor water solubility and low oral bioavailability (<i>F</i>) in rat suggested that the lead could benefit from further SAR studies to improve the biophysical characteristics of the compound. Optimization of in vitro potency and aqueous solubility led to the discovery of <b>2o</b> (ERDRP-00519), a potent inhibitor of MeV (EC₅₀ = 60 nM) with an aqueous solubility of approximately 60 μg/mL. The agent shows a 10-fold exposure (AUC/<i>C</i>_max) increase in the rat model relative to <b>2</b>, displays near dose proportionality in the range of 10–50 mg/kg, and exhibits good oral bioavailability (<i>F</i> = 39%). The significant solubility increase appears linked to the improved oral bioavailability

Identification of Non-Nucleoside Inhibitors of the Respiratory Syncytial Virus Polymerase Complex

Respiratory syncytial virus (RSV) represents a threat to infants, the elderly, and the immunocompromised. RSV entry blockers are in clinical trials, but escape mutations challenge their potential. In search of RSV inhibitors, we have integrated a signature resistance mutation into a recombinant RSV virus and applied the strain to high-throughput screening. Counterscreening of candidates returned 14 confirmed hits with activities in the nano- to low-micromolar range. All blocked RSV polymerase activity in minigenome assays. Compound <b>1a</b> (GRP-74915) was selected for development based on activity (EC₅₀ = 0.21 μM, selectivity index (SI) 40) and scaffold. Resynthesis confirmed the potency of the compound, which suppressed viral RNA synthesis in infected cells. However, metabolic testing revealed a short half-life in the presence of mouse hepatocyte fractions. Metabolite tracking and chemical elaboration combined with 3D-quantitative structure–activity relationship modeling yielded analogues (i.e., <b>8n</b>: EC₅₀ = 0.06 μM, SI 500) that establish a platform for the development of a therapeutic candidate

Synthesis and Metabolic Studies of Host-Directed Inhibitors for Antiviral Therapy

Targeting host cell factors required for virus replication provides an alternative to targeting pathogen components and represents a promising approach to develop broad-spectrum antiviral therapeutics. High-throughput screening (HTS) identified two classes of inhibitors (<b>2</b> and <b>3</b>) with broad-spectrum antiviral activity against ortho- and paramyxoviruses including influenza A virus (IAV), measles virus (MeV), respiratory syncytial virus (RSV), and human parainfluenza virus type 3 (HPIV3). Hit-to-lead optimization delivered inhibitor <b>28a</b>, with EC₅₀ values of 0.88 and 0.81 μM against IAV strain WSN and MeV strain Edmonston, respectively. It was also found that compound <b>28a</b> delivers good stability in human liver S9 fractions with a half-life of 165 min. These data establish <b>28a</b> as a promising lead for antiviral therapy through a host-directed mechanism

Discovery of a Fluorinated Enigmol Analog with Enhanced <i>in Vivo</i> Pharmacokinetic and Anti-Tumor Properties

The orally bioavailable 1-deoxy-sphingosine analog, Enigmol, has demonstrated anticancer activity in numerous <i>in vivo</i> settings. However, as no Enigmol analog with enhanced potency <i>in vitro</i> has been identified, a new strategy to improve efficacy <i>in vivo</i> by increasing tumor uptake was adopted. Herein, synthesis and biological evaluation of two novel fluorinated Enigmol analogs, CF₃-Enigmol and CF₂-Enigmol, are reported. Each analog was equipotent to Enigmol <i>in vitro</i>, but achieved higher plasma and tissue levels than Enigmol <i>in vivo</i>. Although plasma and tissue exposures were anticipated to trend with fluorine content, CF₂-Enigmol absorbed into tissue at strikingly higher concentrations than CF₃-Enigmol. Using mouse xenograft models of prostate cancer, we also show that CF₃-Enigmol underperformed Enigmol-mediated inhibition of tumor growth and elicited systemic toxicity. By contrast, CF₂-Enigmol was not systemically toxic and demonstrated significantly enhanced antitumor activity as compared to Enigmol

Sphingolipid Analogues Inhibit Development of Malaria Parasites

<i>Plasmodium</i>-infected erythrocytes have been shown to employ sphingolipids from both endogenous metabolism as well as existing host pools. Therapeutic agents that limit these supplies have thus emerged as intriguing, mechanistically distinct putative targets for the treatment of malaria infections. In an initial screen of our library of sphingolipid pathway modulators for efficacy against two strains of the predominant human malaria species <i>Plasmodium falciparum</i> and <i>Plasmodium knowlesi</i>, a series of orally available, 1-deoxysphingoid bases were found to possess promising in vitro antimalarial activity. To better understand the structural requirements that are necessary for this observed activity, a second series of modified analogues were prepared and evaluated. Initial pharmacokinetic assessments of key analogues were investigated to evaluate plasma and red blood cell concentrations in vivo

Detailed histopathological scores of all animals examined in this study.

Individual clinical scores for alveolitis, bronchiolitis, perivascular cuffing (PVC), vasculitis, interstitial pneumonia (IP), and pleuritis. Columns show data medians, symbols represent individual animals; 1-way ANOVA with Tukey’s post hoc test; p values are specified; n values are specified in Fig 4F. (TIF)</p

Discovery of Tetrahydroisoquinoline-Based CXCR4 Antagonists

A de novo hit-to-lead effort involving the redesign of benzimidazole-containing antagonists of the CXCR4 receptor resulted in the discovery of a novel series of 1,2,3,4-tetrahydroisoquinoline (TIQ) analogues. In general, this series of compounds show good potencies (3–650 nM) in assays involving CXCR4 function, including both inhibition of attachment of X4 HIV-1_IIIB virus in MAGI-CCR5/CXCR4 cells and inhibition of calcium release in Chem-1 cells. Series profiling permitted the identification of TIQ-(<i>R</i>)-stereoisomer <b>15</b> as a potent and selective CXCR4 antagonist lead candidate with a promising in vitro profile. The drug-like properties of <b>15</b> were determined in ADME in vitro studies, revealing low metabolic liability potential. Further in vivo evaluations included pharmacokinetic experiments in rats and mice, where <b>15</b> was shown to have oral bioavailability (<i>F</i> = 63%) and resulted in the mobilization of white blood cells (WBCs) in a dose-dependent manner

All statistical analyses performed for this study.

All statistical analyses performed for this study.</p

Effect of 4’-FlU on the antiviral immune response and lung histopathology.

a)In vivo Bioplex and histopathology study schematic. b) Lung viral titers in animals treated as in (a). c-d) Changes in IL-6 (c) and TNF-α (d) levels present in BALF of animals treated as in (a), relative to levels at time of infection. Lines in (b) intersect, and symbols show, geometric means ± SD, lines in (c-d) intersect, and symbols show, data medians with 95% CI; 2-way ANOVA with Tukey’s post hoc test; P values are given. e) Representative photomicrographs of lung tissue extracted 5 days after infection of animals treated as in (a). Tissues of two individual animals per study arm are shown at 10× magnification; scale bar denotes 100 μm; Br, Bronchiole; Bl, Blood vessel. f) Histopathology scores of animals treated as in (a). Lungs were extracted 5 days after infection. Scores for each animal represents a mean of individual alveolitis, bronchiolitis, vasculitis, pleuritis, perivascular cuffing (PVC), and interstitial pneumonia (IP) scores. Columns represent data medians with 95% CI; symbols show mean scores for each individual animal; 1-way ANOVA with Dunnett’s post hoc test, P values and n values for each study arm are specified.</p