Anti-infectives Developed as Racemic Drugs in the 21st Century: Norm or Exception?

This viewpoint outlines the case for developing new chemical entities (NCEs) as racemates in infectious diseases and where both enantiomers and racemate retain similar on- and off-target activities as well as similar PK profiles. There are not major regulatory impediments for the development of a racemic drug, and minimizing the manufacturing costs becomes a particularly important objective when bringing an anti-infective therapeutic to the marketplace in the endemic settings of infectious diseases.

Ring-fused dimethoxybenzimidazole-benzimidazolequinone (DMBBQ): tunable halogenation and quinone formation using NaX/Oxone

Ring-fused benzimidazolequinones are well-known anti-tumour agents, but dimeric ring-fused adducts are new. The alicyclic [1,2-a] ring-fused dimethoxybenzimidazole-benzimidazolequinone (DMBBQ) intermediate allows late-stage functionalization of bis-p-benzimidazolequinones. DMBBQs are chlorinated and brominated at the p-dimethoxybenzene site using nontoxic sodium halide and Oxone in HFIP/water. X-ray crystallography is used to rationalize site preference in terms of the discontinuity in conjugation in the DMBBQ system. Quinone formation occurs by increasing in situ halogen generation and water. Conversely, radical trifluoromethylation occurs at the quinone of the DMBBQ.

Correction: Visible-light unmasking of heterocyclic quinone methide radicals from alkoxyamines

Correction for 'Visible-light unmasking of heterocyclic quinone methide radicals from alkoxyamines' by Patrick Kielty et al., Chem. Commun., 2019, 55, 14665-14668, DOI: 10.1039/C9CC08261A.

The Critical Role of Passive Permeability in Designing Successful Drugs

Passive permeability is a key property in drug disposition and delivery. It is critical for gastrointestinal absorption, brain penetration, renal reabsorption, defining clearance mechanisms and drug-drug interactions. Passive diffusion rate is translatable across tissues and animal species, while the extent of absorption is dependent on drug properties, as well as in vivo physiology/pathophysiology. Design principles have been developed to guide medicinal chemistry to enhance absorption, which combine the balance of aqueous solubility, permeability and the sometimes unfavorable compound characteristic demanded by the target. Permeability assays have been implemented that enable rapid development of structure-permeability relationships for absorption improvement. Future advances in assay development to reduce nonspecific binding and improve mass balance will enable more accurately measurement of passive permeability. Design principles that integrate potency, selectivity, passive permeability and other ADMET properties facilitate rapid advancement of successful drug candidates to patients.

Tyrosine Kinase Inhibitor Therapy for Brain Metastases in Non-Small-Cell Lung Cancer: A Primer for Radiologists

Treatment options for patients who develop brain metastases secondary to non-small-cell lung cancer have rapidly expanded in recent years. As a key adjunct to surgical and radiation therapy options, systemic therapies are now a critical component of the oncologic management of metastatic CNS disease in many patients with non-small-cell lung cancer. The aim of this review article was to provide a guide for radiologists, outlining the role of systemic therapies in metastatic non-small-cell lung cancer, with a focus on tyrosine kinase inhibitors. The critical role of the blood-brain barrier in the development of systemic therapies will be described. The final sections of this review will provide an overview of current imaging-based guidelines for therapy response. The utility of the Response Assessment in Neuro-Oncology criteria will be discussed, with a focus on how to use the response criteria in the assessment of patients treated with systemic and traditional therapies.

An in vitro toolbox to accelerate anti-malarial drug discovery and development

Background

Modelling and simulation are being increasingly utilized to support the discovery and development of new anti-malarial drugs. These approaches require reliable in vitro data for physicochemical properties, permeability, binding, intrinsic clearance and cytochrome P450 inhibition. This work was conducted to generate an in vitro data toolbox using standardized methods for a set of 45 anti-malarial drugs and to assess changes in physicochemical properties in relation to changing target product and candidate profiles.

Methods

Ionization constants were determined by potentiometric titration and partition coefficients were measured using a shake-flask method. Solubility was assessed in biorelevant media and permeability coefficients and efflux ratios were determined using Caco-2 cell monolayers. Binding to plasma and media proteins was measured using either ultracentrifugation or rapid equilibrium dialysis. Metabolic stability and cytochrome P450 inhibition were assessed using human liver microsomes. Sample analysis was conducted by LC–MS/MS.

Results

Both solubility and fraction unbound decreased, and permeability and unbound intrinsic clearance increased, with increasing Log D_7.4. In general, development compounds were somewhat more lipophilic than legacy drugs. For many compounds, permeability and protein binding were challenging to assess and both required the use of experimental conditions that minimized the impact of non-specific binding. Intrinsic clearance in human liver microsomes was varied across the data set and several compounds exhibited no measurable substrate loss under the conditions used. Inhibition of cytochrome P450 enzymes was minimal for most compounds.

Conclusions

This is the first data set to describe in vitro properties for 45 legacy and development anti-malarial drugs. The studies identified several practical methodological issues common to many of the more lipophilic compounds and highlighted areas which require more work to customize experimental conditions for compounds being designed to meet the new target product profiles. The dataset will be a valuable tool for malaria researchers aiming to develop PBPK models for the prediction of human PK properties and/or drug–drug interactions. Furthermore, generation of this comprehensive data set within a single laboratory allows direct comparison of properties across a large dataset and evaluation of changing property trends that have occurred over time with changing target product and candidate profiles.

Intracellular and Intraorgan Concentrations of Small Molecule Drugs: Theory, Uncertainties in Infectious Diseases and Oncology, and Promise

The distribution of a drug within the body should be considered as involving movement of unbound drug between the various aqueous spaces of the body. At true steady state, even for a compound of restricted lipoidal permeability, unbound concentrations in all aqueous compartments (blood, extracellular, and intracellular) are considered identical, unless a compartment has a clearance/transport process. In contrast, total drug concentrations may differ greatly, reflecting binding or partitioning into constituents of each compartment. For most highly lipid permeable drugs, this uniform unbound concentration is expected to apply. However, many compounds have restricted lipoidal permeability and are subjected to transport/clearance processes causing a gradient between intracellular and extracellular unbound concentrations even at steady state. Additional concerns arise where the drug target resides in a site of limited vascularity. Many misleading assumptions about drug concentrations and access to drug targets are based on total drug. Correction, if made, is usually by measuring tissue binding, but this is limited by the lack of homogenicity of the organ or compartment. Rather than looking for technology to measure the unbound concentration it may be better to focus on designing high lipoidal permeable molecules with a high chance of achieving a uniform unbound drug concentration. It is hoped this paper will stimulate greater understanding of the path from circulation to cell interior, and thereby in part avoid or minimize the need to provide the experimentally very determining, and sometimes still questionable, answer to this problem.

Visible-light unmasking of heterocyclic quinone methide radicals from alkoxyamines

Controllable room-temperature visible-light activated nitroxide (TEMPO)-release from benzimidazolequinone alkoxyamines and bis-alkoxyamines.

Selective Methylmagnesium Chloride Mediated Acetylations of Isosorbide: A Route to Powerful Nitric Oxide Donor Furoxans

Isosorbide was functionalized with furoxan for the first time to give adducts that release nitric oxide up to 7.5 times faster than the commercial vasodilator, isosorbide-5-mononitrate (Is5N). The synthesis was facilitated by MeMgCl-mediated selective acetylation of isosorbide or selective deacetylation of isosorbide-2,5-diacetate, which was rationalized in terms of a more stable 5-alkoxide magnesium salt using DFT. Isosorbide-furoxans are safer to handle than Is5N due to greater thermal stability.

Safety Assessment of Acyl Glucuronides-A Simplified Paradigm

While simple O- (ether-linked) and N-glucuronide drug conjugates generally are unreactive and considered benign from a safety perspective, the acyl glucuronides that derive from metabolism of carboxylic acid-containing xenobiotics can exhibit a degree of chemical reactivity that is dependent upon their molecular structure. As a result, concerns have arisen over the safety of acyl glucuronides as a class, several members of which have been implicated in the toxicity of their respective parent drugs. However, direct evidence in support of these claims remains sparse, and due to frequently encountered species differences in the systemic exposure to acyl glucuronides (both of the parent drug and oxidized derivatives thereof), coupled with their instability in aqueous media and potential to undergo chemical rearrangement (acyl migration), qualification of these conjugates by traditional safety assessment methods can be very challenging. In this Commentary, we discuss alternative (non-acyl glucuronide) mechanisms by which carboxylic acids may cause serious adverse reactions, and propose a novel, practical approach to compare systemic exposure to acyl glucuronide metabolites in humans to that in animal species used in preclinical safety assessment based on relative estimates of the total body burden of these circulating conjugates.

Nonneuroleptic Treatment of Disruptive Behavior in Organic Mental Syndromes

OBJECTIVE:

To summarize the literature describing nonneuroleptic treatments of unacceptably disruptive behavior in chronically institutionalized psychiatric patients with mental retardation, autism, organic brain syndrome, and dementia.

DATA SOURCES:

Relevant articles were identified from a MEDLINE search of the above diagnoses linked with “aggression” and “psychomotor agitation.” Additional references were found in the bibliographies of these articles.

STUDY SELECTION/DATA EXTRACTION:

The studies reviewed were limited to prospective evaluations of nonneuroleptic drug therapy of these behavior disturbances. Case reports, case series, and retrospective studies were excluded. Studies of patients with schizophrenia, affective disorders, and personality disorders were also excluded.

DATA SYNTHESIS:

Studies of lithium, beta-blockers, carbamazepine, benzodiazepines, and buspirone were adequate for review. As a rule, these studies are hampered by poor design. The lithium studies suggest that mentally retarded patients with behavior disturbances may respond to lithium treatment. The beta-blocker studies suggest improvement in patients with mental retardation, autism, organic brain syndrome, and dementia. Neuroleptic discontinuation or a decrease in dose was possible in some patients. The carbamazepine studies were inconclusive. Carbamazepine should be reserved for patients with concomitant seizure disorders. Benzodiazepines were helpful in treating elderly demented patients. Thus far, buspirone has been evaluated in only a few, poorly designed studies and is not yet recommended for treatment of behavior disturbances.

CONCLUSIONS:

Legislation has restricted the use of neuroleptics in many patients receiving long-term healthcare. Despite the questionable validity of the studies reviewed, lithium, beta-blockers, carbamazepine, and benzodiazepines may be considered as alternatives to neuroleptics in selected cases.

Pigment production and isotopic fractionations in continuous culture: okenone producing purple sulfur bacteria Part II

Okenone is a carotenoid pigment unique to certain members of Chromatiaceae, the dominant family of purple sulfur bacteria (PSB) found in euxinic photic zones. Diagenetic alteration of okenone produces okenane, the only recognized molecular fossil unique to PSB. The in vivo concentrations of okenone and bacteriochlorophyll a (Bchl a) on a per cell basis were monitored and quantified as a function of light intensity in continuous cultures of the purple sulfur bacterium Marichromatium purpuratum (Mpurp1591). We show that okenone-producing PSB have constant bacteriochlorophyll to carotenoid ratios in light-harvesting antenna complexes. The in vivo concentrations of Bchl a, 0.151 ± 0.012 fmol cell(-1), and okenone, 0.103 ± 0.012 fmol cell(-1), were not dependent on average light intensity (10-225 Lux) at both steady and non-steady states. This observation revealed that in autotrophic continuous cultures of Mpurp1591, there was a constant ratio for okenone to Bchl a of 1:1.5. Okenone was therefore constitutively produced in planktonic cultures of PSB, regardless of light intensity. This confirms the legitimacy of okenone as a signature for autotrophic planktonic PSB and by extrapolation water column euxinia. We measured the δ(13)C, δ(15)N, and δ(34)S bulk biomass values from cells collected daily and determined the isotopic fractionations of Mpurp1591. There was no statistical relationship in the bulk isotope measurements or stable isotope fractionations to light intensity or cell density under steady and non-steady-state conditions. The carbon isotope fractionation between okenone and Bchl a with respect to overall bulk biomass ((13)ε pigment - biomass) was 2.2 ± 0.4‰ and -4.1 ± 0.9‰, respectively. The carbon isotopic fractionation (13ε pigment-CO2) for the production of pigments in PSB is more variable than previously thought with our reported values for okenone at -15.5 ± 1.2‰ and -21.8 ± 1.7‰ for Bchl a.

Ecologically and geologically relevant isotope signatures of C, N, and S: okenone producing purple sulfur bacteria Part I

Purple sulfur bacteria (PSB) are known to couple the carbon, nitrogen, and sulfur cycling in euxinic environments. This is the first study with multiple strains and species of okenone-producing PSB to examine the carbon (C), nitrogen (N), and sulfur (S) metabolisms and isotopic signatures in controlled laboratory conditions, investigating what isotopic fractionations might be recorded in modern environments and the geologic record. PSB play an integral role in the ecology of euxinic environments and produce the unique molecular fossil okenane, derived from the diagenetic alteration of the carotenoid pigment okenone. Cultures of Marichromatium purpuratum 1591 (Mpurp1591) were observed to have carbon isotope fractionations ((13)ε biomass - CO2), via RuBisCO, ranging from -16.1 to -23.2‰ during exponential and stationary phases of growth. Cultures of Thiocapsa marina 5653 (Tmar5653) and Mpurp1591 had a nitrogen isotope fractionation ((15)ε biomass - NH 4) of -15‰, via glutamate dehydrogenase, measured and recorded for the first time in PSB. The δ(34) SVCDT values and amount of stored elemental sulfur for Mpurp1591 cells grown autotrophically and photoheterotrophically were dependent upon their carbon metabolic pathways. We show that PSB may contribute to the isotopic enrichments observed in modern and ancient anoxic basins. In a photoheterotrophic culture of Mpurp1591 that switched to autotrophy once the organic substrate was consumed, there were bulk biomass δ(13)C values that span a broader range than recorded across the Late Devonian, Permian-Triassic, Triassic-Jurassic, and OAE2 mass extinction boundaries. This finding stresses the complexities in interpreting and assigning δ(13)C values to bulk organic matter preserved in the geologic record.

Which metabolites circulate?

Characterization of the circulating metabolites for a new chemical entity in humans is essential for safety assessment, an understanding of their contributions to pharmacologic activities, and their potential involvement in drug-drug interactions. This review examines the abundance of metabolites relative to the total parent drug [metabolite-to-parent (M/P) ratio] from 125 drugs in relation to their structural and physicochemical characteristics, lipoidal permeability, protein binding, and fractional formation from parent (fm). Our analysis suggests that fm is the major determinant of total drug M/P ratio for amine, alcohol, N- and S-oxide, and carboxylic acid metabolites. Passage from the hepatocyte to systemic circulation does not appear to be limiting owing to the vast majority of metabolites formed being relatively lipid permeable. In some cases, active transport plays an important role in this process (e.g., carboxylic acid metabolites). Differences in total parent drug clearance and metabolite clearance are attenuated by the reduction in lipophilicity introduced by the metabolic step and resultant compensatory changes in unbound clearance and protein binding. A small subclass of these drugs (e.g., terfenadine) is unintentional prodrugs with very high parent drug clearance, resulting in very high M/P ratios. In contrast, arenol metabolites show a more complex relationship with fm due largely to the new metabolic routes (conjugation) available to the metabolite compared with the parent drug molecule. For these metabolites, a more thorough understanding of the elimination clearance of the metabolite is critical to discern the likelihood of whether the phenol will constitute a major circulating metabolite.

Abstract P6-11-10: IBL2001: Phase I/II study of a novel dose-dense schedule of oral indibulin for the treatment of metastastic breast cancer

Background: Indibulin (ZI0-301) is a novel, oral, synthetic small molecule microtubule inhibitor which binds tubulin at a different site than taxanes and vinca alkaloids. Preclinical data demonstrate indibulin does not interact with acetylated (neuronal) tubulins and in clinical studies has not exhibited the neurotoxicity associated with other tubulin binders. Indibulin has potent antitumor activity in human cancer cell lines, including multidrug-, taxane-, and vinblastine-resistant. Norton-Simon modeling based on cell line data suggested that dose dense (dd) administration could optimize efficacy while limiting toxicity.

Methods: Eligible patients (pts) have metastatic or unresectable locally advanced breast cancer, ECOG performance status ≤ 2, adequate organ function, measurable or nonmeasurable disease and any number of prior therapies. Uncontrolled gastrointestinal malabsorption syndrome and grade 2 or higher peripheral neuropathy are the principal exclusions. Adverse events (AEs) are graded by CTCAE v. 4.0. Objective disease status is evaluated according to RECIST 1.1. The primary objective of the phase (Ph) I portion of the study is to determine the maximum tolerated dose (MTD) of indibulin when given in dd fashion 5 days treatment, 9 days rest using standard 3+3 dose escalation schema.

Peripheral neuritis in psittacine birds with proventricular dilatation disease

Necropsies were performed on 14 psittacine birds of various species suspected to have proventricular dilatation disease (PDD). Eight of the birds exhibited neurological signs (seizures, ataxia, tremors and uncoordinated movements) and digestive tract signs (crop stasis, regurgitation, inappetance and presence of undigested food in the faeces). At necropsy, the birds had pectoral muscle atrophy, proventricular and ventricular distention, thinning of the gizzard wall, and duodenal dilation. In addition, five birds had a transparent fluid (0.2 to 1.0 ml) in the subarachnoidal space of the brain, and one bird had dilatation of the right ventricle of the heart. The histological lesions differed from earlier reports of PDD in that peripheral (sciatic, brachial and vagal) neuritis was seen in addition to myenteric ganglioneuritis, myocarditis, adrenalitis, myelitis and encephalitis.

Impact of the pharmaceutical sciences on health care: a reflection over the past 50 years

During the last century, particularly the latter half, spectacular progress has been made in improving the health and longevity of people. The reasons are many, but the development of medicines has played a critical role. This report documents and reflects on the impressive contribution that those working in the pharmaceutical sciences have made to healthcare over the past 50 years. It is divided into six sections (drug discovery; absorption, distribution, metabolism, and excretion; pharmacokinetics and pharmacodynamics; drug formulation; drug regulation; and drug utilization), each describing key contributions that have been made in the progression of medicines, from conception to use. A common thread throughout is the application of translational science to the improvement of drug discovery, development, and therapeutic application. Each section has been coordinated by a leading scientist who was asked, after consulting widely with many colleagues across the globe, to identify "The five most influential ideas/concepts/developments introduced by 'pharmaceutical scientists' (in their field) over the past 50 years?" Although one cannot predict where the important breakthroughs will come in the future to meet the unmet medical needs, the evidence presented in this report should leave no doubt that those engaged in the pharmaceutical sciences will continue to make their contributions heavily felt.

Discovery and ADMET: Where are we now

The gradual alignment with all of drug metabolism with all aspects of drug discovery and development has led to a complete realignment of the way the work is conducted. From a background of conducting bespoke in vivo studies much of the work is now in a high throughput screening mode. Large technological advances have been made, but the nature of drug metabolism processes, being multi-system and promiscuous means that much of the help provided to the medicinal chemistry is reactive rather than based on fundamental disposition structure-activity relationships. Lessons learned around the chemical and physicochemical properties more often associated with successfull discovery and development projects are only moderately helpful when the high value pharmacological targets of today only yield potent ligands outside of the boundaries these properties describe. Pivotal to the impact of these properties is the intrinsic permeability of a molecule, something not as widely recognised as perhaps it should be. Metabolic lability is still a problem and the tactics employed are unchanged in 20 years: attempt to lower lipophilicity, if it is too high overall or introduce blocking groups, particularly halogens, after identifying the sites of metabolism Perhaps the greatest success drug metabolism science has had over the last fifteen years is it's pivotal role in characterising drug-drug interactions and providing screening systems and computational models to investigate them. It still has many undeveloped areas of the science such as the role of metabolites in drug activity and why compounds vary in their extent of biliary excretion.

The effect of plasma protein binding on in vivo efficacy: misconceptions in drug discovery

Data from in vitro plasma protein binding experiments that determine the fraction of protein-bound drug are frequently used in drug discovery to guide structure design and to prioritize compounds for in vivo studies. However, we consider that these practices are usually misleading, because in vivo efficacy is determined by the free (unbound) drug concentration surrounding the therapeutic target, not by the free drug fraction. These practices yield no enhancement of the in vivo free drug concentration. So, decisions based on free drug fraction could result in the wrong compounds being advanced through drug discovery programmes. This Perspective provides guidance on the application of plasma protein binding information in drug discovery.

High resolution imaging of actin filaments in living cells under physilogically relevant conditions using apertureless near-field microscopy

Living cells were used to demonstrate the potential biological applications of the apertureless SNOM when operating under fluid. An oral epithelial squamous cell carcinoma cell line (H357) was imaged under physiological-like conditions using apertureless SNOM following staining with FITC-Phalloidin which preferentially stains intracellular actin filaments of the cytoskeleton. Compared with simultaneously obtained AFM topographic image, the apertureless SNOM data provides greater detail on these cellular structures and the spatial resolution of the apertureless SNOM fluorescence image appears to be about 100 nm.

Three-dimensional structures reveal multiple ADP/ATP binding modes for a synthetic class of artificial proteins

The creation of synthetic enzymes with predefined functions represents a major challenge in future synthetic biology applications. Here, we describe six structures of de novo proteins that have been determined using protein crystallography to address how simple enzymes perform catalysis. Three structures are of a protein, DX, selected for its stability and ability to tightly bind ATP. Despite the addition of ATP to the crystallization conditions, the presence of a bound but distorted ATP was found only under excess ATP conditions, with ADP being present under equimolar conditions or when crystallized for a prolonged period of time. A bound ADP cofactor was evident when Asp was substituted for Val at residue 65, but ATP in a linear configuration is present when Phe was substituted for Tyr at residue 43. These new structures complement previously determined structures of DX and the protein with the Phe 43 to Tyr substitution [Simmons, C. R., et al. (2009) ACS Chem. Biol. 4, 649-658] and together demonstrate the multiple ADP/ATP binding modes from which a model emerges in which the DX protein binds ATP in a configuration that represents a transitional state for the catalysis of ATP to ADP through a slow, metal-free reaction capable of multiple turnovers. This unusual observation suggests that design-free methods can be used to generate novel protein scaffolds that are tailor-made for catalysis.

Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

P-glycoprotein related drug interactions: clinical importance and a consideration of disease states

IMPORTANCE OF THE FIELD

P-glycoprotein (P-gp) is the most characterized drug transporter in terms of its clinical relevance for pharmacokinetic disposition and interaction with other medicines. Clinically significant P-gp related drug interactions appear restricted to digoxin. P-gp may act as a major barrier to current and effective drug treatment in a number of diseases including cancer, AIDS, Alzheimer's and epilepsy due to its expression in tumors, lymphocytes, cell membranes of brain capillaries and the choroid plexus.

AREAS COVERED IN THIS REVIEW

This review summarizes the current understanding of P-gp structure/function, clinical importance of P-gp related drug interactions and the modulatory role this transporter may contribute towards drug efficacy in disease states such as cancer, AIDS, Alzheimer's and epilepsy.

WHAT THE READER WILL GAIN

The reader will gain an understanding that the clinical relevance of P-gp in drug interactions is limited. In certain disease states, P-gp in barrier tissues can modulate changes in regional distribution.

TAKE HOME MESSAGE

P-gp inhibition in isolation will not result in clinically important alterations in systemic exposure; however, P-gp transport may be of significance in barrier tissues (tumors, lymphocytes, brain) resulting in attenuated efficacy.

Refining the in vitro and in vivo critical parameters for P-glycoprotein, [I]/IC50 and [I2]/IC50, that allow for the exclusion of drug candidates from clinical digoxin interaction studies

The objective of this work was to further investigate the reasons for disconcordant clinical digoxin drug interactions (DDIs) particularly for false negative where in vitro data suggests no P-glycoprotein (P-gp) related DDI but a clinically relevant DDI is evident. Applying statistical analyses of binary classification and receiver operating characteristic (ROC), revised cutoff values for ratio of [I]/IC(50) < 0.1 and [I(2)]/IC(50) < 5 were identified to minimize the error rate, a reduction of false negative rate to 9% from 36% (based on individual ratios). The steady state total C(max) at highest dose of the inhibitor is defined as [I] and the ratio of the nominal maximal gastrointestinal concentration determined for highest dose per 250 mL volume defined [I(2)](.) We also investigated the reliability of the clinical data to see if recommendations can be made on values that would allow predictions of 25% change in digoxin exposure. The literature derived clinical digoxin interaction studies were statistically powered to detect relevant changes in exposure associated with digitalis toxicities. Our analysis identified that many co-meds administered with digoxin are cardiovascular (CV) agents. Moreover, our investigations also suggest that the presence of CV agents may alter cardiac output and/or kidney function that may act alone or are additional components to enhance digoxin exposure along with P-gp interaction. While we recommend digoxin as the probe substrate to define P-gp inhibitory potency for clinical assessment, we observed high concordance in P-gp inhibitory potency for calcein AM as a probe substrate.

Spectrum of the isotropic diffuse gamma-ray emission derived from first-year Fermi Large Area Telescope data

We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called "extragalactic" diffuse gamma-ray emission (EGB). This component of the diffuse gamma-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modeling of the bright foreground diffuse Galactic gamma-ray emission, the detected LAT sources, and the solar gamma-ray emission. We find the spectrum of the EGB is consistent with a power law with a differential spectral index gamma = 2.41 +/- 0.05 and intensity I(>100 MeV) = (1.03 +/- 0.17) x 10(-5) cm(-2) s(-1) sr(-1), where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.

Fermi large area telescope search for photon lines from 30 to 200 GeV and dark matter implications

Dark matter (DM) particle annihilation or decay can produce monochromatic gamma rays readily distinguishable from astrophysical sources. gamma-ray line limits from 30 to 200 GeV obtained from 11 months of Fermi Large Area Space Telescope data from 20-300 GeV are presented using a selection based on requirements for a gamma-ray line analysis, and integrated over most of the sky. We obtain gamma-ray line flux upper limits in the range 0.6-4.5x10{-9} cm{-2} s{-1}, and give corresponding DM annihilation cross-section and decay lifetime limits. Theoretical implications are briefly discussed.

The use of C(av) rather than AUC in safety assessment

Toxicokinetic data have traditionally been presented as maximum observed plasma concentrations (C(max)) and area under the concentration time curve (AUC) values. These values have been used to compare exposures across studies and species to provide valuable interpretation of drug safety data. Increasingly, questions are asked of toxicology studies to more accurately describe the concentration effect relationships in terms of compound affinity for target and off-target receptors. C(max) values can immediately be referenced to known pharmacological activities, particularly when the extent of plasma protein binding is taken into account. This provides a measure of the more pharmacologically relevant free drug exposure. AUC values on the other hand contain the component of time, which means that direct comparison to pharmacological activity values are not immediately possible. Conversion of AUC to average plasma concentration (C(av)) provides a simple and convenient means to allow such a comparison without losing any information imparted by AUC values. In this paper, the benefit and advantage of applying C(av) values is illustrated using examples taken from the literature.

Anti-interleukin-5 antibody treatment (mepolizumab) in active eosinophilic oesophagitis: a randomised, placebo-controlled, double-blind trial

OBJECTIVE

Eosinophilic oesophagitis (EoO) is a clinicopathological condition defined by proton pump inhibitor-refractory oesophageal symptoms combined with oesophageal eosinophilia. The pharmacodynamic effect of mepolizumab (a humanised anti-interleukin-5 monoclonal antibody) in EoO was evaluated.

METHODS

Eleven adults with active EoO (>20 peak eosinophil number/high power field (hpf) and dysphagia) were randomised to 750 mg of mepolizumab (n = 5) or placebo (n = 6) and received two intravenous infusions, 1 week apart. Those not in complete remission (<5 peak eosinophil number/hpf) after 8 weeks received two further doses 4 weeks apart, 1500 mg of mepolizumab or placebo. The effect of mepolizumab was assessed clinically, endoscopically, histologically, and via blood and tissue biomarkers.

RESULTS

As assessed by immunofluorescence, a marked reduction of mean oesophageal eosinophilia (p = 0.03) was seen in the mepolizumab group (-54%) compared with the placebo group (-5%) 4 weeks after initiation of treatment. No further reduction of eosinophil numbers was observed in response to the two additional infusions in either group. Mepolizumab reduced tenascin C (p = 0.033) and transforming growth factor beta1 (p = 0.05) expression in the oesophageal epithelial layer 13 weeks after initiation of treatment. Clinically, limited improvement of symptoms was seen, although a trend was seen between 4 and 13 weeks after initiation of mepolizumab treatment. Mepolizumab was well tolerated.

CONCLUSIONS

Mepolizumab significantly reduced eosinophil numbers in oesophageal tissues in adult patients with active EoO, and changes in the expression of molecules associated with oesophageal remodelling were reversed. Minimal clinical improvement was achieved in a subgroup of patients with EoO. Mepolizumab had an acceptable safety profile, even at the high 1500 mg dose level.

TRIAL REGISTRATION NUMBER

NCT00274703.

Fermi large area telescope measurements of the diffuse gamma-ray emission at intermediate galactic latitudes

The diffuse galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess gamma-ray emission greater, > or approximately equal to 1 GeV relative to diffuse galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called "EGRET GeV excess"). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10 degrees < or = |b| < or = 20 degrees. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

Detection of high-energy gamma-ray emission from the globular cluster 47 Tucanae with Fermi

We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17sigma from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that they contain. The spectral shape of 47 Tucanae is consistent with gamma-ray emission from a population of millisecond pulsars. The observed gamma-ray luminosity implies an upper limit of 60 millisecond pulsars present in 47 Tucanae.

Will biomedical innovation change the future of healthcare?

Healthcare costs in all industrial nations have increased and payors are starting to look at new ways to contain costs and at new funding models. The business model of pharmaceutical companies is also undergoing rapid changes - potentially disruptive new modalities, such as RNAi, therapeutic vaccines, and cell therapy are emerging, R&D costs have increased year on year, pressures on drug pricing and the efficacy and safety of medicines are mounting. Change is therefore inevitable and already ongoing in healthcare systems and pharmaceutical companies alike. This paper presents several major forces which could drive different future scenarios including: R&D costs, the source of payments for medicines and the emergence of new modalities.