Objective
To examine region‐ and substrate‐specific autoradiographic and in vitro binding patterns of positron emission tomography tracer F‐18‐AV‐1451 (previously known as T807), tailored to allow in ...vivo detection of paired helical filament‐tau–containing lesions, and to determine whether there is off‐target binding to other amyloid/non‐amyloid proteins.
Methods
We applied F‐18‐AV‐1451 phosphor screen autoradiography, F‐18‐AV‐1451 nuclear emulsion autoradiography, and H‐3‐AV‐1451 in vitro binding assays to the study of postmortem samples from patients with a definite pathological diagnosis of Alzheimer disease, frontotemporal lobar degeneration–tau, frontotemporal lobar degeneration–transactive response DNA binding protein 43 (TDP‐43), progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies, multiple system atrophy, cerebral amyloid angiopathy and elderly controls free of pathology.
Results
Our data suggest that F‐18‐AV‐1451 strongly binds to tau lesions primarily made of paired helical filaments in Alzheimer brains (eg, intraneuronal and extraneuronal tangles and dystrophic neurites), but does not seem to bind to a significant extent to neuronal and glial inclusions mainly composed of straight tau filaments in non‐Alzheimer tauopathy brains or to lesions containing β‐amyloid, α‐synuclein, or TDP‐43. F‐18‐AV‐1451 off‐target binding to neuromelanin‐ and melanin‐containing cells and, to a lesser extent, to brain hemorrhagic lesions was identified.
Interpretation
Our data suggest that F‐18‐AV‐1451 holds promise as a surrogate marker for the detection of brain tau pathology in the form of tangles and paired helical filament‐tau–containing neurites in Alzheimer brains but also point to its relatively lower affinity for lesions primarily made of straight tau filaments in non‐Alzheimer tauopathy cases and to the existence of some F‐18‐AV‐1451 off‐target binding. These findings provide important insights for interpreting in vivo patterns of F‐18‐AV‐1451 retention. Ann Neurol 2015 Ann Neurol 2015;78:Ann Neurol 2015;78:679–696
Current antifungal agents cover a majority of opportunistic fungal pathogens; however, breakthrough invasive fungal infections continue to occur and increasingly involve relatively uncommon yeasts ...and molds, which often exhibit decreased susceptibility. APX001A (manogepix) is a first-in-class small-molecule inhibitor of the conserved fungal Gwt1 protein. This enzyme is required for acylation of inositol during glycosylphosphatidylinositol anchor biosynthesis. APX001A is active against the major fungal pathogens, i.e.,
(except
),
, and hard-to-treat molds, including
and
In this study, we tested APX001A and comparators against 1,706 contemporary clinical fungal isolates collected in 2017 from 68 medical centers in North America (37.3%), Europe (43.4%), the Asia-Pacific region (12.7%), or Latin America (6.6%). Among the isolates tested, 78.5% were
spp., 3.9% were non-
yeasts, including 30 (1.8%)
var.
isolates, 14.7% were
spp., and 2.9% were other molds. All isolates were tested by CLSI reference broth microdilution. APX001A (MIC
, 0.008 μg/ml; MIC
, 0.06 μg/ml) was the most active agent tested against
sp. isolates; corresponding anidulafungin, micafungin, and fluconazole MIC
values were 16- to 64-fold higher. Similarly, APX001A (MIC
, 0.25 μg/ml; MIC
, 0.5 μg/ml) was ≥8-fold more active than anidulafungin, micafungin, and fluconazole against
var.
Against
spp., AXP001A (50% minimal effective concentration MEC
, 0.015 μg/ml; MEC
, 0.03 μg/ml) was comparable in activity to anidulafungin and micafungin.
isolates (>98%) exhibited a wild-type phenotype for the mold-active triazoles (itraconazole, posaconazole, and voriconazole). APX001A was highly active against uncommon species of
, non-
yeasts, and rare molds, including 11 isolates of
spp. (MEC values, 0.015 to 0.06 μg/ml). APX001A demonstrated potent
activity against recent fungal isolates, including echinocandin- and fluconazole-resistant strains. The extended spectrum of APX001A was also notable for its potency against many less common but antifungal-resistant strains. Further studies are in progress to evaluate the clinical utility of the methyl phosphate prodrug, APX001, in difficult-to-treat resistant fungal infections.
Colorectal cancer (CRC) is a highly heterogeneous disease, for which prognosis has been relegated to clinicopathologic staging for decades. There is a need to stratify subpopulations of CRC on a ...molecular basis to better predict outcome and assign therapies. Here we report targeted exome-sequencing of 1,321 cancer-related genes on 468 tumour specimens, which identified a subset of 17 genes that best classify CRC, with APC playing a central role in predicting overall survival. APC may assume 0, 1 or 2 truncating mutations, each with a striking differential impact on survival. Tumours lacking any APC mutation carry a worse prognosis than single APC mutation tumours; however, two APC mutation tumours with mutant KRAS and TP53 confer the poorest survival among all the subgroups examined. Our study demonstrates a prognostic role for APC and suggests that sequencing of APC may have clinical utility in the routine staging and potential therapeutic assignment for CRC.
Genome-wide association studies (GWAS) have successfully identified tens of thousands of genetic variants associated with various phenotypes, but together they explain only a fraction of ...heritability, suggesting many variants have yet to be discovered. Recently it has been recognized that incorporating functional information of genetic variants can improve power for identifying novel loci. For example, S-PrediXcan and TWAS tested the association of predicted gene expression with phenotypes based on GWAS summary statistics by leveraging the information on genetic regulation of gene expression and found many novel loci. However, as genetic variants may have effects on more than one gene and through different mechanisms, these methods likely only capture part of the total effects of these variants. In this paper, we propose a summary statistics-based mixed effects score test (sMiST) that tests for the total effect of both the effect of the mediator by imputing genetically predicted gene expression, like S-PrediXcan and TWAS, and the direct effects of individual variants. It allows for multiple functional annotations and multiple genetically predicted mediators. It can also perform conditional association analysis while adjusting for other genetic variants (e.g., known loci for the phenotype). Extensive simulation and real data analyses demonstrate that sMiST yields p-values that agree well with those obtained from individual level data but with substantively improved computational speed. Importantly, a broad application of sMiST to GWAS is possible, as only summary statistics of genetic variant associations are required. We apply sMiST to a large-scale GWAS of colorectal cancer using summary statistics from ∼120, 000 study participants and gene expression data from the Genotype-Tissue Expression (GTEx) project. We identify several novel and secondary independent genetic loci.
•Manogepix is active against Candida spp., including Candida auris.•Manogepix is active against echinocandin-resistant Candida spp. isolates.•Manogepix is active against Aspergillus spp. ...isolates.•Manogepix is active against A. fumigatus isolates with elevated azole MICs and cyp mutations.•Manogepix is active against rare mould isolates, including Scedosporium spp.
: Manogepix, the active moiety of the prodrug fosmanogepix, is a novel antifungal with activity against major fungal pathogens including Candida (except Candida krusei), Aspergillus and difficult-to-treat/rare moulds. We tested manogepix and comparators against 2669 contemporary (2018–2019) fungal isolates collected from 82 medical centres in North America (42.3%), Europe (37.9%), Asia-Pacific (12.3%) and Latin America (7.6%). Of these, 70.7% were Candida spp., 3.6% were non-Candida yeasts including 49 Cryptococcus neoformans var. grubii, 21.7% were Aspergillus spp. and 4.1% were other moulds.
Isolates were tested for antifungal susceptibility by the CLSI reference broth microdilution method.
Manogepix (MIC50/90, 0.008/0.06 mg/L) was the most active agent tested against Candida spp. isolates; corresponding anidulafungin, micafungin and fluconazole MIC90 values were 16- to 64-fold higher. Similarly, manogepix (MIC50/90, 0.5/2 mg/L) was ≥4-fold more active than anidulafungin, micafungin and fluconazole against C. neoformans var. grubii. Against Aspergillus spp., manogepix (MEC50/90, 0.015/0.03 mg/L) had comparable activity to anidulafungin and micafungin. Low manogepix concentrations inhibited uncommon species of Candida, non-Candida yeasts, and rare moulds including Scedosporium spp. and Lomentospora (Scedosporium) prolificans.
Manogepix exhibited potent activity against contemporary fungal isolates, including echinocandin- and azole-resistant strains of Candida and Aspergillus spp., respectively. Although rare, Candida strains that were non-wild type for manogepix demonstrated resistance to fluconazole. However, the clinical relevance of this finding is unknown. The extended spectrum of manogepix is noteworthy for its activity against many less-common yet antifungal-resistant strains. Clinical studies are underway to evaluate the utility of fosmanogepix against difficult-to-treat resistant fungal infections.
Objectives
The single‐ and multiple‐dose pharmacokinetics (PK) of tedizolid were examined after oral administration of tedizolid phosphate disodium (TPD), including the effect of food on PK. The ...relative bioavailability of TPD to the free acid tedizolid phosphate was determined to bridge the results of these and other studies to the solid form of the prodrug selected for further development.
Design
Randomized placebo‐controlled, double‐blind single‐ and multiple‐ascending dose studies and randomized open‐label, crossover food effect and relative bioavailability studies.
Setting
Clinical Research Units.
Participants
Healthy subjects.
Intervention
Study TR701‐101 enrolled 40 subjects in single‐ascending dose (200–1200 mg TPD or placebo) and 40 subjects in 21‐day multiple‐ascending dose (200, 300, or 400 mg TPD once/day; 600 mg linezolid twice/day; or placebo) arms. Study TR701‐103 was a food‐effect study in 12 subjects administered 600 mg TPD. Study TR701‐108 was a relative bioavailability study in 12 subjects administered 150‐mg tedizolid equivalents as TPD or tedizolid phosphate.
Measurements and Main Results
Plasma concentrations of the prodrug tedizolid phosphate, its active moiety tedizolid, and/or linezolid were collected. After administration of 200 to 600 mg TPD, tedizolid values increased approximately dose proportionally in area under the concentration‐time curve (AUC) and maximum plasma concentration (Cmax). Tedizolid half‐life values were approximately 2‐fold greater compared with linezolid. TPD administration with food delayed tedizolid absorption and reduced Cmax relative to the fasted state but did not alter AUC. Minimal accumulation was predicted and observed for tedizolid, whereas observed accumulation of linezolid exceeded predictions based on single‐dose PK. Comparable PK of tedizolid was observed following oral administration of either TPD or tedizolid phosphate. In the multiple‐ascending dose study, 3 of 24 tedizolid subjects were withdrawn under prespecified stopping rules (one each of elevated alanine aminotransferase, low reticulocyte count, or low white blood cell count), as was 1 of 8 linezolid subjects (low reticulocyte count).
Conclusions
Overall, tedizolid has a favorable PK profile, a half‐life that supports once daily administration, and no nonlinearities at steady state. Tedizolid phosphate can be administered without regard to food.
Abstract The in vitro activity and spectrum of tedizolid and comparators were analyzed against 6884 Gram-positive clinical isolates collected from multiple US and European sites as part of the ...Surveillance of Tedizolid Activity and Resistance Program in 2011 and 2012. Organisms included 4499 Staphylococcus aureus , 537 coagulase-negative staphylococci (CoNS), 873 enterococci, and 975 β-hemolytic streptococci. The MIC values that inhibited 90% of the isolates within each group (MIC90 ) were 0.25 μg/mL for Staphylococcus epidermidis and β-hemolytic streptococci and 0.5 μg/mL for S. aureus , other CoNS, and enterococci. Of 16 isolates with elevated tedizolid or linezolid MIC values (intermediate or resistant isolates), 10 had mutations in the genes encoding 23S rRNA (primarily G2576T), 5 had mutations in the genes encoding ribosomal proteins L3 or L4, and 5 carried the cfr multidrug resistance gene. Overall, tedizolid showed excellent activity against Gram-positive bacteria and was at least 4-fold more potent than linezolid against wild-type and linezolid-resistant isolates. Given the low overall frequency of isolates that would be resistant to tedizolid at the proposed break point of 0.5 μg/mL (0.19%) and potent activity against contemporary US and European isolates, tedizolid has the potential to serve as a valuable therapeutic option in the treatment of infections caused by Gram-positive pathogens.
Circulating white blood cell and platelet traits are clinically linked to various disease outcomes and differ across individuals and ancestry groups. Genetic factors play an important role in ...determining these traits and many loci have been identified. However, most of these findings were identified in populations of European ancestry (EA), with African Americans (AA), Hispanics/Latinos (HL), and other races/ethnicities being severely underrepresented.
We performed ancestry-combined and ancestry-specific genome-wide association studies (GWAS) for white blood cell and platelet traits in the ancestrally diverse Population Architecture using Genomics and Epidemiology (PAGE) Study, including 16,201 AA, 21,347 HL, and 27,236 EA participants. We identified six novel findings at suggestive significance (P < 5E-8), which need confirmation, and independent signals at six previously established regions at genome-wide significance (P < 2E-9). We confirmed multiple previously reported genome-wide significant variants in the single variant association analysis and multiple genes using PrediXcan. Evaluation of loci reported from a Euro-centric GWAS indicated attenuation of effect estimates in AA and HL compared to EA populations.
Our results highlighted the potential to identify ancestry-specific and ancestry-agnostic variants in participants with diverse backgrounds and advocate for continued efforts in improving inclusion of racially/ethnically diverse populations in genetic association studies for complex traits.
Quantitative red blood cell (RBC) traits are highly polygenic clinically relevant traits, with approximately 500 reported GWAS loci. The majority of RBC trait GWAS have been performed in European- or ...East Asian-ancestry populations, despite evidence that rare or ancestry-specific variation contributes substantially to RBC trait heritability. Recently developed combined-phenotype methods which leverage genetic trait correlation to improve statistical power have not yet been applied to these traits. Here we leveraged correlation of seven quantitative RBC traits in performing a combined-phenotype analysis in a multi-ethnic study population.
We used the adaptive sum of powered scores (aSPU) test to assess combined-phenotype associations between ~ 21 million SNPs and seven RBC traits in a multi-ethnic population (maximum n = 67,885 participants; 24% African American, 30% Hispanic/Latino, and 43% European American; 76% female). Thirty-nine loci in our multi-ethnic population contained at least one significant association signal (p < 5E-9), with lead SNPs at nine loci significantly associated with three or more RBC traits. A majority of the lead SNPs were common (MAF > 5%) across all ancestral populations. Nineteen additional independent association signals were identified at seven known loci (HFE, KIT, HBS1L/MYB, CITED2/FILNC1, ABO, HBA1/2, and PLIN4/5). For example, the HBA1/2 locus contained 14 conditionally independent association signals, 11 of which were previously unreported and are specific to African and Amerindian ancestries. One variant in this region was common in all ancestries, but exhibited a narrower LD block in African Americans than European Americans or Hispanics/Latinos. GTEx eQTL analysis of all independent lead SNPs yielded 31 significant associations in relevant tissues, over half of which were not at the gene immediately proximal to the lead SNP.
This work identified seven loci containing multiple independent association signals for RBC traits using a combined-phenotype approach, which may improve discovery in genetically correlated traits. Highly complex genetic architecture at the HBA1/2 locus was only revealed by the inclusion of African Americans and Hispanics/Latinos, underscoring the continued importance of expanding large GWAS to include ancestrally diverse populations.
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