Use of patient-reported outcomes (PRO) data to complement exposure-response analysis in early clinical cancer drug development.

BACKGROUND: This proof-of-concept retrospective case study investigated whether patient-reported outcomes (PRO) instruments, designed to capture symptomatic adverse event data, could identity a known exposure-response (ER) relationship for safety characterized in an original FDA analysis of an approved anti-cancer agent. PRO instruments have been designed to uniquely quantify the tolerability aspects of exposure-associated symptomatic adverse events. We explored whether standard ER analyses of clinician-reported safety data for symptomatic adverse events could be complemented by ER analysis using PRO data that capture and quantify the tolerability aspects of these same symptomatic adverse events. METHODS: Exposure-associated adverse event data for diarrhea were analyzed in parallel in 120 patients enrolled in a clinical trial using physician reported Common Terminology Criteria for Adverse Events (CTCAE) and patient-reported symptomatic adverse event data captured by the National Cancer Institute's (NCI) PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE) instrument. Comparative ER analyses of diarrhea were conducted using the same dataset. Results from the CTCAE and PRO-CTCAE ER analyses were assessed for consistency with the ER relationship for diarrhea established in the original NDA using a 750-patient dataset. The analysis was limited to the 120-patient subset with parallel CTCAE and PRO-CTCAE assessments. RESULTS: Within the same 120-patient dataset, ER analysis using dense, longitudinal PRO-CTCAE-derived data was sensitive to identify the known ER relationship for diarrhea, whereas the standard CTCAE based ER analysis was not. CONCLUSIONS: ER analysis using PRO assessed symptomatic adverse event data may be a sensitive tool to complement traditional ER analysis. Improved identification of relationships for safety, by including quantification of the tolerability aspect of symptomatic adverse events using PRO instruments, may be useful to improve the sensitivity of exposure response analysis to support early clinical trial dosage optimization strategies, where decision making occurs within limited small patient datasets.

Computational prediction of MHC anchor locations guides neoantigen identification and prioritization.

Neoantigens are tumor-specific peptide sequences resulting from sources such as somatic DNA mutations. Upon loading onto major histocompatibility complex (MHC) molecules, they can trigger recognition by T cells. Accurate neoantigen identification is thus critical for both designing cancer vaccines and predicting response to immunotherapies. Neoantigen identification and prioritization relies on correctly predicting whether the presenting peptide sequence can successfully induce an immune response. Because most somatic mutations are single-nucleotide variants, changes between wild-type and mutated peptides are typically subtle and require cautious interpretation. A potentially underappreciated variable in neoantigen prediction pipelines is the mutation position within the peptide relative to its anchor positions for the patient's specific MHC molecules. Whereas a subset of peptide positions are presented to the T cell receptor for recognition, others are responsible for anchoring to the MHC, making these positional considerations critical for predicting T cell responses. We computationally predicted anchor positions for different peptide lengths for 328 common HLA alleles and identified unique anchoring patterns among them. Analysis of 923 tumor samples shows that 6 to 38% of neoantigen candidates are potentially misclassified and can be rescued using allele-specific knowledge of anchor positions. A subset of anchor results were orthogonally validated using protein crystallography structures. Representative anchor trends were experimentally validated using peptide-MHC stability assays and competition binding assays. By incorporating our anchor prediction results into neoantigen prediction pipelines, we hope to formalize, streamline, and improve the identification process for relevant clinical studies.

Neoantigen-targeted CD8+ T cell responses with PD-1 blockade therapy.

Neoantigens are peptides derived from non-synonymous mutations presented by human leukocyte antigens (HLAs), which are recognized by antitumour T cells1-14. The large HLA allele diversity and limiting clinical samples have restricted the study of the landscape of neoantigen-targeted T cell responses in patients over their treatment course. Here we applied recently developed technologies15-17 to capture neoantigen-specific T cells from blood and tumours from patients with metastatic melanoma with or without response to anti-programmed death receptor 1 (PD-1) immunotherapy. We generated personalized libraries of neoantigen-HLA capture reagents to single-cell isolate the T cells and clone their T cell receptors (neoTCRs). Multiple T cells with different neoTCR sequences (T cell clonotypes) recognized a limited number of mutations in samples from seven patients with long-lasting clinical responses. These neoTCR clonotypes were recurrently detected over time in the blood and tumour. Samples from four patients with no response to anti-PD-1 also demonstrated neoantigen-specific T cell responses in the blood and tumour to a restricted number of mutations with lower TCR polyclonality and were not recurrently detected in sequential samples. Reconstitution of the neoTCRs in donor T cells using non-viral CRISPR-Cas9 gene editing demonstrated specific recognition and cytotoxicity to patient-matched melanoma cell lines. Thus, effective anti-PD-1 immunotherapy is associated with the presence of polyclonal CD8+ T cells in the tumour and blood specific for a limited number of immunodominant mutations, which are recurrently recognized over time.

Integrated analysis of genomic and transcriptomic data for the discovery of splice-associated variants in cancer.

Somatic mutations within non-coding regions and even exons may have unidentified regulatory consequences that are often overlooked in analysis workflows. Here we present RegTools ( www.regtools.org ), a computationally efficient, free, and open-source software package designed to integrate somatic variants from genomic data with splice junctions from bulk or single cell transcriptomic data to identify variants that may cause aberrant splicing. We apply RegTools to over 9000 tumor samples with both tumor DNA and RNA sequence data. RegTools discovers 235,778 events where a splice-associated variant significantly increases the splicing of a particular junction, across 158,200 unique variants and 131,212 unique junctions. To characterize these somatic variants and their associated splice isoforms, we annotate them with the Variant Effect Predictor, SpliceAI, and Genotype-Tissue Expression junction counts and compare our results to other tools that integrate genomic and transcriptomic data. While many events are corroborated by the aforementioned tools, the flexibility of RegTools also allows us to identify splice-associated variants in known cancer drivers, such as TP53, CDKN2A, and B2M, and other genes.

FDA Approval Summary: Capmatinib and Tepotinib for the Treatment of Metastatic NSCLC Harboring MET Exon 14 Skipping Mutations or Alterations.

The FDA approved capmatinib and tepotinib on May 6, 2020, and February 3, 2021, respectively. Capmatinib is indicated for patients with metastatic non-small cell lung cancer (mNSCLC) whose tumors have a mutation leading to mesenchymal-epithelial transition (MET) exon 14 skipping as detected by an FDA-approved test. Tepotinib is indicated for mNSCLC harboring MET exon 14 skipping alterations. The approvals were based on trials GEOMETRY mono-1 (capmatinib) and VISION (tepotinib). In GEOMETRY mono-1, overall response rate (ORR) per Blinded Independent Review Committee (BIRC) was 68% [95% confidence interval (CI), 48-84] with median duration of response (DoR) 12.6 months (95% CI, 5.5-25.3) in 28 treatment-naïve patients and 41% (95% CI: 29, 53) with median DoR 9.7 months (95% CI, 5.5-13) in 69 previously treated patients with NSCLC with mutations leading to MET exon 14 skipping. In VISION, ORR per BIRC was 43% (95% CI: 32, 56) with median DoR 10.8 months (95% CI, 6.9-not estimable) in 69 treatment-naïve patients and 43% (95% CI, 33-55) with median DoR 11.1 months (95% CI, 9.5-18.5) in 83 previously-treated patients with NSCLC harboring MET exon 14 alterations. These are the first two therapies to be FDA approved specifically for patients with metastatic NSCLC with MET exon 14 skipping.

FDA Approval Summary: Osimertinib for Adjuvant Treatment of Surgically Resected Non-Small Cell Lung Cancer, a Collaborative Project Orbis Review.

On December 18, 2020, the FDA approved osimertinib as adjuvant therapy in patients with non-small cell lung cancer (NSCLC) whose tumors have EGFR exon 19 deletions or exon 21 (L858R) mutations, as detected by an FDA-approved test. The approval was based on the ADAURA study, in which 682 patients with NSCLC were randomized to receive osimertinib (n = 339) or placebo (n = 343). Disease-free survival (DFS) in the overall population (stage IB-IIIA) was improved for patients who received osimertinib, with an HR of 0.20; 95% confidence interval (CI), 0.15-0.27; P < 0.0001. Median DFS was not reached for the osimertinib arm compared with 27.5 months (95% CI, 22.0-35.0) for patients receiving placebo. Overall survival data were not mature at the time of the approval. This application was reviewed under FDA's Project Orbis, in collaboration with Australia Therapeutic Goods Administration, Brazil ANVISA, Health Canada, Singapore Health Sciences Authority, Switzerland Swissmedic, and the United Kingdom Medicines and Healthcare products Regulatory Agency. This is the first targeted therapy adjuvant approval for NSCLC and has practice-changing implications.

Increased hypospadias risk by GREM1 rs3743104[G] in the southern Han Chinese population.

Hypospadias is a common congenital genitourinary malformation characterized by ventral opening of the urethral meatus. As a member of the bone morphogenic protein antagonist family, GREM1 has been identified as associated with susceptibility to hypospadias in the European population. The present study was designed to elaborate on the mutual relationship between replicated single-nucleotide polymorphisms (SNPs) and hypospadias in Asia's largest case-control study in the Southern Han Chinese population involving 577 patients and 654 controls. Our results demonstrate that the GREM1 risk allele rs3743104[G] markedly increases the risk of mild/moderate and severe hypospadias (P<0.01, 0.28≤OR≤0.66). GTEx expression quantitative trait locus data revealed that the eQTL SNP rs3743104 has more associations of eQTL SNP rs3743104 and GREM1 targets in pituitary tissues. Additionally, Bioinformatics and Luciferase Assays show that miR-182 is identified as a suppressor for GREM1 expression, likely through regulation of its binding affinity to rs3743104 locus. In conclusion, the GREM1 risk allele rs3743104[G] increases hypospadias susceptibility in mild/moderate and severe cases among the southern Han population. rs3743104 regulates GREM1 expression by altering the binding affinity of miR-182 to their locus. Collectively, this study provides new evidence that GREM1 rs3743104 is associated with an increased risk of hypospadias. These findings provide a promising biomarker and merit further exploration.

FDA Approval Summary: Tucatinib for the Treatment of Patients with Advanced or Metastatic HER2-positive Breast Cancer.

On April 17, 2020, the FDA approved tucatinib in combination with trastuzumab and capecitabine for the treatment of patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting. This was the first new molecular entity evaluated under Project Orbis, an FDA Oncology Center of Excellence initiative, which supports concurrent review of oncology drugs by multiple global health authorities. Approval was based on the HER2CLIMB trial, which randomized patients to receive tucatinib or placebo with trastuzumab and capecitabine. Tucatinib demonstrated efficacy compared with placebo in progression-free survival [PFS; HR: 0.54; 95% confidence interval (CI): 0.42-0.71; P < 0.00001] and overall survival (OS; HR: 0.66; 95% CI, 0.50-0.87; P = 0.00480). Patients with either treated and stable or active brain metastases made up 48% of the study population. PFS in patients with brain metastases confirmed benefit (HR: 0.48; 95% CI, 0.34-0.69; P < 0.00001). The benefit in patients with brain metastases allowed for inclusion of this specific population in the indication. Important safety signals included diarrhea and hepatotoxicity which are listed under Warnings and Precautions. This article summarizes the FDA thought process and data supporting the favorable benefit-risk profile and approval of tucatinib.

PA5001 gene involves in swimming motility and biofilm formation in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a nosocomial human pathogen causing infections in immunocompromised patients. To explore new genes involved in P. aeruginosa swimming motility, Mu transposon mutagenesis library was screened for isolates with altered swimming motility. Eleven nonmobile mutants were identified. Sequence analysis shows the nonmobile phenotype of one isolate was attributed to the inactivation of PA5001 gene. PA5001 knockout mutant based on the PAK lab strain also displayed comparable phenotypes suggesting the universal gene function regardless of strain. Exotic PA5001 gene fragment provided on expressing plasmid was capable of storing nonmobile phenotype of PA5001 mutant, suggesting the functional involvement of PA5001 gene on bacterial swimming. Impact of PA5001 inactivation on biofilm formation was examined, as adhesion and interaction during biofilm formation is highly dependent of bacterial mobility. The result shows that normal architecture of biofilm was disrupted in the mutant. Complementing by exotic PA5001 gene fragment resulted in the restoration of biofilm phenotype. Our results provide evidences suggesting the functional participation of PA5001 gene in bacterial mobility and biofilm formation. The critical function by PA5001 in bacterial motility and biofilm might serve as hint for the novel target for the treatment of chronic infections caused by P. aeruginosa.

pVACtools: A Computational Toolkit to Identify and Visualize Cancer Neoantigens.

Identification of neoantigens is a critical step in predicting response to checkpoint blockade therapy and design of personalized cancer vaccines. This is a cross-disciplinary challenge, involving genomics, proteomics, immunology, and computational approaches. We have built a computational framework called pVACtools that, when paired with a well-established genomics pipeline, produces an end-to-end solution for neoantigen characterization. pVACtools supports identification of altered peptides from different mechanisms, including point mutations, in-frame and frameshift insertions and deletions, and gene fusions. Prediction of peptide:MHC binding is accomplished by supporting an ensemble of MHC Class I and II binding algorithms within a framework designed to facilitate the incorporation of additional algorithms. Prioritization of predicted peptides occurs by integrating diverse data, including mutant allele expression, peptide binding affinities, and determination whether a mutation is clonal or subclonal. Interactive visualization via a Web interface allows clinical users to efficiently generate, review, and interpret results, selecting candidate peptides for individual patient vaccine designs. Additional modules support design choices needed for competing vaccine delivery approaches. One such module optimizes peptide ordering to minimize junctional epitopes in DNA vector vaccines. Downstream analysis commands for synthetic long peptide vaccines are available to assess candidates for factors that influence peptide synthesis. All of the aforementioned steps are executed via a modular workflow consisting of tools for neoantigen prediction from somatic alterations (pVACseq and pVACfuse), prioritization, and selection using a graphical Web-based interface (pVACviz), and design of DNA vector-based vaccines (pVACvector) and synthetic long peptide vaccines. pVACtools is available at http://www.pvactools.org.

Best practices for bioinformatic characterization of neoantigens for clinical utility.

Neoantigens are newly formed peptides created from somatic mutations that are capable of inducing tumor-specific T cell recognition. Recently, researchers and clinicians have leveraged next generation sequencing technologies to identify neoantigens and to create personalized immunotherapies for cancer treatment. To create a personalized cancer vaccine, neoantigens must be computationally predicted from matched tumor-normal sequencing data, and then ranked according to their predicted capability in stimulating a T cell response. This candidate neoantigen prediction process involves multiple steps, including somatic mutation identification, HLA typing, peptide processing, and peptide-MHC binding prediction. The general workflow has been utilized for many preclinical and clinical trials, but there is no current consensus approach and few established best practices. In this article, we review recent discoveries, summarize the available computational tools, and provide analysis considerations for each step, including neoantigen prediction, prioritization, delivery, and validation methods. In addition to reviewing the current state of neoantigen analysis, we provide practical guidance, specific recommendations, and extensive discussion of critical concepts and points of confusion in the practice of neoantigen characterization for clinical use. Finally, we outline necessary areas of development, including the need to improve HLA class II typing accuracy, to expand software support for diverse neoantigen sources, and to incorporate clinical response data to improve neoantigen prediction algorithms. The ultimate goal of neoantigen characterization workflows is to create personalized vaccines that improve patient outcomes in diverse cancer types.

A mathematical model-based analysis of the time-kill kinetics of ceftazidime/avibactam against Pseudomonas aeruginosa.

Objectives: To characterize quantitatively the effect of avibactam in potentiating ceftazidime against MDR Pseudomonas aeruginosa by developing a mathematical model to describe the bacterial response to constant concentration time-kill information and validating it using both constant and time-varying concentration-effect data from in vitro and in vivo infection systems. Methods: The time course of the bacterial population dynamics in the presence of static concentrations of ceftazidime and avibactam was modelled using a two-state pharmacokinetic/pharmacodynamic (PK/PD) model, consisting of active and resting states, to account for bactericidal activities, bacteria-mediated ceftazidime degradation and inhibition of degradation by avibactam. Ceftazidime's effect on the bacterial population was described as an enhancement of the death rate of the active population, with the effect of avibactam being to increase ceftazidime potency. Model validation was performed by comparing simulated time courses of bacterial responses with those from in vitro and in vivo experimental exposures of ceftazidime and avibactam that represented those predicted in an average patient dosed with 2 g/0.5 g ceftazidime/avibactam administered every 8 h as 2 h infusions. Results: The two-state model successfully described the bacterial population dynamics, ceftazidime degradation and its inhibition by avibactam. For external validation, the model correctly predicted the bacterial response of P. aeruginosa isolates evaluated in in vitro hollow-fibre and in vivo neutropenic mouse thigh and lung infection models. Conclusions: The PK/PD model and modelled strains successfully replicated the spread in activity when compared with a large selection of P. aeruginosa strains reported in the literature.

Influence of cAMP receptor protein (CRP) on bacterial virulence and transcriptional regulation of allS by CRP in Klebsiella pneumoniae.

cAMP receptor protein (CRP) is one of the most important transcriptional regulators, which can regulate large quantities of operons in different bacteria. The gene allS was well-known as allantoin-utilizing capability and involving in bacterial virulence in Klebsiella pneumoniae (K. pneumoniae). The specific DNA recognition motif of transcription regulator CRP was found in allS promoter region. Therefore, this study is aimed to investigate the function of CRP on virulence and its transcriptional regulation mechanism to gene allS in K. pneumoniae. The wild-type (WT) K. pneumoniae NTUH-2044, crp knockout (Kp-Δcrp) and the complemented knockout (KpC-Δcrp) strains were used to determine the function of crp gene. The lacZ fusion, qRT-PCR, electrophoretic mobility shift and DNase I footprinting assays were performed to study the transcriptional regulation of CRP on allS. The result showed a decreased virulence in crp knockout strain. Complement through supplementing crp fragment in expression plasmid partially restore virulence of knockout bacteria. The CRP could bind to the allS promoter-proximal region and the binding site was further refined to be located from 60bp to 94bp upstream of the allS promoter. Based on these results, we proposed that CRP is an essential virulence regulator and knock out of crp gene will result in reduced virulence in K. pneumoniae. In the meantime, the transcription of gene allS is positively regulated by CRP via directly binding to upstream of allS promoter.

Gentamicin dosing strategy in patients with end-stage renal disease receiving haemodialysis: evaluation using a semi-mechanistic pharmacokinetic/pharmacodynamic model.

OBJECTIVES: Gentamicin is widely used in end-stage renal disease (ESRD) patients for the treatment of infections. The goal of this study was to find the most reasonable dosing regimen for gentamicin in ESRD patients receiving haemodialysis. METHODS: The in vitro antimicrobial activity of gentamicin was evaluated by static and dynamic time-kill experiments against three bacterial strains of MSSA, MRSA and Pseudomonas aeruginosa. A semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model was established afterwards, allowing the characterization of the antibacterial effect of gentamicin in the human body. The model was utilized to assess dosing regimens of gentamicin in ESRD patients receiving haemodialysis, taking both efficacy and safety into account. RESULTS: The PK/PD model was capable of describing the bacterial response to gentamicin exposure in all three strains. Simulation based on the PK/PD model showed that pre-dialysis and post-dialysis dosing would bring comparable benefit to the ESRD patient regardless of whether the PK/PD target (fCmax/MIC >8-fold) was achieved, while the post-dialysis dosing resulted in a significantly lower trough concentration. The result of simulated dose fractionation demonstrated that both fCmax/MIC and fAUC(0-24)/MIC are strong predictors of drug effectiveness, but the PK/PD model would provide a more precise prediction of antibacterial activity as well as valuable information on dose selection in ESRD patients receiving haemodialysis. CONCLUSIONS: Our study supports the original FDA label with regard to the dosing regimen of gentamicin in ESRD patients, which offers adequate clinical benefit as well as an acceptable safety profile.

Theory and Application of Microdialysis in Pharmacokinetic Studies.

The major aim of current pharmacokinetic studies is to investigate the drug absorption, disposition, metabolism and excretion in animals and humans. The time courses of plasma concentrations are usually characterized and linked to the pharmacodynamic effect to evaluate drug efficacy. However, under certain circumstance, site of action is located in tissues rather than in circulation, which requires direct measurement of tissue concentrations instead of plasma concentrations. Microdialysis is one of those techniques that have been demonstrated to be feasible for measurement of free drug concentration in many tissues, and is capable of being applied in most pharmacokinetic studies to enhance drug efficacy and reduce the unnecessary side effects. This paper reviews this technique from the perspective of theoretical background including the history of development, basic principle, components and their functions. Moreover, the relative recovery of microdialysis and the key factors are discussed, followed by calibration methods available to reduce the systemic bias. In addition, microdialysis is compared with conventional tissue sampling technique for superiorities and limitations. At last, the application of microdialysis in pharmacokinetic study is summarized, especially in assessment of drug efficacy and safety in different tissues. So far, microdialysis is a valuable tool in drug development and will play an unique role in a variety of pharmacokinetic and pharmacodynamic studies in future.

A novel regulator PA5022 (aefA) is involved in swimming motility, biofilm formation and elastase activity of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an opportunistic pathogen contributing to a range of nosocomial infections. To identify new genes involved in P. aeruginosa swimming motility, an important mechanism of pathogenesis, mutants with altered swimming motility patterns from Mu transposon mutagenesis library of the P. aeruginosa clinical strain PA68 were isolated and characterized. We identified a mutant with transposon inactivation of PA5022 has completely abolished its swimming motility while still possesses a normal terminal flagellum according to electronic microscopy analysis. Microscopic examination revealed that the PA5022 mutant forms thicker biofilms compared to the PA68 wild-type strain and is impaired in its elastase activity. To exclude the possibility of genetic diversity in affecting gene functions among different strains, we constructed a PA5022 knock out mutant based on the PAK lab strain. The PAKΔPA5022 has similar phenotypes to the PA5022 (PA5022::Mu) mutant of PA68 strain. Furthermore, transcriptional fusion assays were carried out to investigate the regulatory mechanism of PA5022 by using the PlasI-lacZ, PrhlI-lacZ, PrpoN-lacZ, PrpoS-lacZ, PqscR-lacZ, PvqsR-lacZ fusions. ß-Galactosidase activity assays indicated that the expression of the vqsR, lasI and rhlI promotors was reduced in the PA5022 mutant compared to the PA68 wild-type. Our study showed that PA5022 links swimming motility and quorum sensing, which might be an important regulator for the pathogenesis of P. aeruginosa.

N-acetyltransferase genotypes and the pharmacokinetics and tolerability of para-aminosalicylic acid in patients with drug-resistant pulmonary tuberculosis.

The aim of this study was to examine the relationships between N-acetyltransferase genotypes, pharmacokinetics, and tolerability of granular slow-release para-aminosalicylic acid (GSR-PAS) in tuberculosis patients. The study was a randomized, two-period, open-label, crossover design wherein each patient received 4 g GSR-PAS twice daily or 8 g once daily alternately. The PAS concentration-time profiles were modeled by a one-compartment disposition model with three transit compartments in series to describe its absorption. Patients' NAT1 and NAT2 genotypes were determined by sequencing and restriction enzyme analysis, respectively. The number of daily vomits was modeled by a Poisson probability mass function. Comparisons of other tolerability measures by regimens, gender, and genotypes were evaluated by a linear mixed-effects model. The covariate effects associated with efavirenz, gender, and NAT1*3, NAT1*14, and NAT2*5 alleles corresponded to 25, 37, -17, -48, and -27% changes, respectively, in oral clearance of PAS. The NAT1*10 allele did not influence drug clearance. The time above the MIC of 1 mg/liter was significantly different between the two regimens but not influenced by the NAT1 or NAT2 genotypes. The occurrence and intensity of intolerance differed little between regimens. Four grams of GSR-PAS twice daily but not 8 g once daily ensured concentrations exceeding the MIC (1 mg/liter) throughout the dosing interval; PAS intolerance was not related to maximum PAS concentrations over the doses studied and was not more frequent after once-daily dosing. We confirm that the slow phenotype conferred by the NAT1*14 and NAT1*3 alleles resulted in higher PAS exposure but found no evidence of increased activity of the NAT1*10 allele.

Interferon-Inducible Transmembrane Protein 3 Genetic Variant rs12252 and Influenza Susceptibility and Severity: A Meta-Analysis.

BACKGROUND: The pandemic influenza A (H1N1) pdm09 virus, avian influenza A (H5N1) virus, and influenza A (H7N9) virus induced severe morbidity and mortality throughout the world. Previous studies suggested a close association between the interferon-induced transmembrane protein-3 (IFITM3) genetic variant rs12252 and influenza. Here, we explored the correlation between the rs12252 and influenza susceptibility and severity using meta-analysis. METHODS: Relevant studies published before May 22, 2014 were retrieved from PubMed, ISI web of knowledge, EBSCO, and Cochrane central register of controlled trials databases. Association between rs12252 and influenza susceptibility and severity were determined using statistical analysis of odds ratios (ORs). RESULTS: A total of four studies consisting of 445 cases and 4180 controls were included in our analysis. Generally, there is increased risk of influenza in subjects carrying rs12252 in the recessive model (CC vs. CT+TT: OR = 2.35, 95% CI: 1.49-3.70, P<0.001), the dominant model (CC+CT vs. TT: OR=1.60, 95% CI: 1.18-2.22, P=0.003), the homozygote comparison (CC vs. TT: OR=4.11, 95% CI: 2.15-7.84, P<0.001), and the allele contrast (C vs. T: OR=1.67, 95% CI: 1.32-2.13, P<0.001). Stratification analysis of ethnicity and severity revealed a significant increase in influenza susceptibility by IFITM3-SNP rs12252 among both Asian and Caucasian population. SNP rs12252 shows significant impact on severe infections (P<0.05), but not on mild influenza. Besides, our result also associated rs12252 with influenza severity (severe vs. mild: OR=2.37, 95% CI: 1.32-4.25, P=0.004), (severe vs. control: OR=2.70, 95% CI: 1.85-3.94, P<0.001). CONCLUSION: Our meta-analysis suggests a significant association between a minor IFITM3 allele (SNP rs12252-C) with severe influenza susceptibility, but not in mild influenza subjects, in both UK Caucasians and Han Chinese population. The rs12252-C allele causes a 23.7% higher chance of infection and also constitutes a risk factor for more severe influenza.

Effects of antioxidant gene therapy on the development of diabetic retinopathy and the metabolic memory phenomenon.

PURPOSE: The purpose of this study was to determine the therapeutic effect and mechanism of AAV-MnSOD by intravitreal injection on diabetic retinopathy (DRP) and the metabolic memory phenomenon. METHODS: The effect of hyperglycemia and metabolic memory on the thickness of basement membrane, ratio of pericyte area and cross-sectional area of capillary vessels in the nerve fiber layer and outer plexiform layer; retinal capillary cell apoptosis; number of acellular capillaries and activities of retinal MnSOD and catalase were examined and compared with intravitreal injection of AAV-MnSOD by transmission electron microscopy, TUNEL assay, ELISA, and immunohistochemistry. RESULTS: Hyperglycemia increased the thickness of capillary basement membranes in the nerve fiber layer and outer plexiform layer, decreased the ratio of pericyte area and cross-sectional area of capillary vessels, increased numbers of acellular capillaries and apoptosis of retinal capillary cells, and decreased activities of retinal MnSOD and catalase. Termination of hyperglycemia cannot reverse pathological changes listed above. Intra-vitreal injection of AAV-MnSOD dramatically elevated the level and activities of retinal MnSOD and catalase, and effectively prevented the progression of DRP and the metabolic memory phenomenon. CONCLUSIONS: Increasing reactive oxygen species concentration and continuous decreasing of antioxidant enzyme activity play important roles in DRP and the metabolic memory phenomenon. AAV-MnSOD gene therapy provides a promising strategy to inhibit this blinding disease.

Evaluation of in vitro synergy between vertilmicin and ceftazidime against Pseudomonas aeruginosa using a semi-mechanistic pharmacokinetic/pharmacodynamic model.

The aim of this study was to develop a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model to evaluate the in vitro synergy between vertilmicin and ceftazidime against Pseudomonas aeruginosa. The in vitro antimicrobial activity of vertilmicin alone was initially assessed by static and dynamic time-kill experiments against three bacterial strains, including MSSA, MRSA and P. aeruginosa. The combined killing effect with ceftazidime was then evaluated in a static time-kill study against P. aeruginosa. Vertilmicin displayed a concentration-dependent killing effect against the three bacterial strains, and its short half-life may possibly have a dramatic impact on antimicrobial activities. A two-compartment pharmacodynamic model consisting of drug-susceptible and -resistant compartments was developed to characterise the relationship between drug exposure and bacterial response for the time-kill curves from both monotherapy and combination therapy. Loewe additivity was incorporated into the pharmacodynamic model to describe the drug-drug interactive effect in the combination therapy. For monotherapy, the estimated EC50 of the dynamic time-kill study against each strain was close to its MIC but was higher than that of the static time-kill study. The EC50 of combination therapy was estimated at 2.67 mg/L compared with 4.54 mg/L in monotherapy, indicating an enhanced bactericidal capacity. The drug-drug interactive effect was not significantly synergistic but highly varied at each specific combination. Potential synergistic combinations could be screened using PK/PD modelling and simulation. These results demonstrated that PK/PD modelling provides an innovative approach to assist dose selection of combination vertilmicin and ceftazidime for future clinical study design.