Hyperpolarized helium-3 magnetic resonance lung imaging of non-sedated infants and young children: a proof-of-concept study.

PURPOSE: To develop and evaluate a protocol for hyperpolarized helium-3 (HHe) ventilation magnetic resonance imaging (MRI) of the lungs of non-sedated infants and children. MATERIALS AND METHODS: HHe ventilation MRI was performed on seven children ≤4years old. Contiguous 2D-spiral helium-3 images were acquired sequentially with a scan time of ≤0.2s/slice. RESULTS: Motion-artifact-free, high signal-to-noise ratio (SNR) images of lung ventilation were obtained. Gas was homogeneously distributed in healthy individuals; focal ventilation defects were found in patients with respiratory diseases. CONCLUSION: HHe ventilation MRI can aid assessment of pediatric lung disease even at a young age.

Use of hyperpolarized helium-3 MRI to assess response to ivacaftor treatment in patients with cystic fibrosis.

BACKGROUND: This pilot study evaluated the effect of short- and long-term ivacaftor treatment on hyperpolarized 3He-magnetic resonance imaging (MRI)-defined ventilation defects in patients with cystic fibrosis aged ≥12years with a G551D-CFTR mutation. METHODS: Part A (single-blind) comprised 4weeks of ivacaftor treatment; Part B (open-label) comprised 48weeks of treatment. The primary outcome was change from baseline in total ventilation defect (TVD; total defect volume:total lung volume ratio). RESULTS: Mean change in TVD ranged from -8.2% (p=0.0547) to -12.8% (p=0.0078) in Part A (n=8) and -6.3% (p=0.1953) to -9.0% (p=0.0547) in Part B (n=8) as assessed by human reader and computer algorithm, respectively. CONCLUSIONS: TVD responded to ivacaftor therapy. 3He-MRI provides an individual quantification of disease burden that may be able to detect aspects of the disease missed by population-based spirometry metrics. Assessments by human reader and computer algorithm exhibit similar trends, but the latter appears more sensitive. www.clinicaltrials.gov identifier: NCT01161537.

Evaluating more naturalistic outcome measures: A 1-year smartphone study in multiple sclerosis.

OBJECTIVE: In this cohort of individuals with and without multiple sclerosis (MS), we illustrate some of the novel approaches that smartphones provide to monitor patients with chronic neurologic disorders in their natural setting. METHODS: Thirty-eight participant pairs (MS and cohabitant) aged 18-55 years participated in the study. Each participant received an Android HTC Sensation 4G smartphone containing a custom application suite of 19 tests capturing participant performance and patient-reported outcomes (PROs). Over 1 year, participants were prompted daily to complete one assigned test. RESULTS: A total of 22 patients with MS and 17 cohabitants completed the entire study. Among patients with MS, low scores on PROs relating to mental and visual function were associated with dropout (p < 0.05). We illustrate several novel features of a smartphone platform. First, fluctuations in MS outcomes (e.g., fatigue) were assessed against an individual's ambient environment by linking responses to meteorological data. Second, both response accuracy and speed for the Ishihara color vision test were captured, highlighting the benefits of both active and passive data collection. Third, a new trait, a person-specific learning curve in neuropsychological testing, was identified using spline analysis. Finally, averaging repeated measures over the study yielded the most robust correlation matrix of the different outcome measures. CONCLUSIONS: We report the feasibility of, and barriers to, deploying a smartphone platform to gather useful passive and active performance data at high frequency in an unstructured manner in the field. A smartphone platform may therefore enable large-scale naturalistic studies of patients with MS or other neurologic diseases.

A signature for immune response correlates with HCV treatment outcome in Caucasian subjects.

This data article contains Supplementary material for a published research article describing a whole-blood proteomic signature that predicts treatment outcome for subjects infected with hepatitis C virus (HCV) [1]. The proteomic signature is derived from whole-blood samples from subjects infected with HCV. The article includes detailed experimental and computational methods used in the analysis. The article also includes tables of demographic and other information about the subjects. Finally, the article includes several figures and tables showing detailed results of the analyses (e.g. lists of identified proteins and coefficients/ROC curves for the regression models).

A signature for immune response correlates with HCV treatment outcome in Caucasian subjects.

Broad proteomic profiling was performed on serum samples of phase 2 studies (PROVE1, PROVE2, and PROVE3) of the direct-acting antiviral drug telaprevir in combination with peg-interferon and ribavirin in subjects with HCV. Using only profiling data from subjects treated with peg-interferon and ribavirin, a signature composed of pretreatment levels of 13 components was identified that correlated well (R(2)=0.68) with subjects' underlying immune response as measured by week 4 viral decline and was highly predictive of sustained virologic response in non-African American subjects (AUC=0.99). The signature was validated by predicting in an independent cohort of non-African American subjects treated with telaprevir, peg-interferon and ribavirin (AUC=0.854). Samples from extreme responders were over-represented in these analyses. Proteins identified as differentially-expressed between responders and non-responders to HCV treatment were quantified using multiple reaction monitoring in samples from all Caucasian subjects in the peg-interferon and ribavirin arms of PROVE1 and PROVE2, revealing 15 proteins that were significantly differentially expressed between treatment responders and non-responders. Seven of the proteins are part of focal adhesions or other macromolecular assemblies that form structural links between integrins and the actin cytoskeleton and are involved in antiviral response. BIOLOGICAL SIGNIFICANCE: HCV is a significant health problem. We describe a novel approach for identifying markers that predicts HCV treatment response different treatment regimens and use this approach to identify a novel HCV treatment response signature. The signature has potential to guide optimization of HCV treatment regimens.

Intrahepatic and Peripheral CXCL10 Expression in Hepatitis C Virus-Infected Patients Treated With Telaprevir, Pegylated Interferon, and Ribavirin.

UNLABELLED: We assessed peripheral and liver CXCL10 levels in 15 patients treated with telaprevir/pegylated interferon/ribavirin. Induction of peripheral CXCL10 messenger RNA (mRNA) peaked (mean fold-induction [±SD], 3.1 ± 1.9) between treatment hour 6 and day 2, while induction of intrahepatic CXCL10 mRNA peaked (mean fold-induction [±SD], 1.3 ± 0.54) at hour 10 or day 4. Peripheral CXCL10 levels were higher at treatment hour 10 (P = .032) and day 2 (P = .009) in patients with undetectable virus 2 weeks after treatment initiation. Treatment hour 10 (P = .023) and peak (P = .034) intrahepatic CXCL10 levels were also higher in these patients. CXCL10 did not distinguish treatment responders from nonresponders. In conclusion, CXCL10 identified very rapid virological response in patients treated with a direct-acting antiviral. CLINICAL TRIALS REGISTRATION: NCT00892697.

Assessment of repeatability of hyperpolarized gas MR ventilation functional imaging in cystic fibrosis.

RATIONALE AND OBJECTIVES: Hyperpolarized (HP) gas magnetic resonance imaging (MRI) is an advanced imaging technique that provides high-resolution regional information on lung function without using ionizing radiation. Before this modality can be considered for assessing clinical or investigational interventions, baseline repeatability needs to be established. We assessed repeatability of lung function measurement using HP helium-3 MRI (HP (3)He MRI) in a small cohort of patients with cystic fibrosis (CF). MATERIALS AND METHODS: We examined repeatability of HP (3)He MR images of five patients with CF in four scanning sessions over a 4-week period. We acquired images on a Philips 3.0 Tesla Achieva MRI scanner using a quadrature, flexible, wrap-around, (3)He radiofrequency coil with a fast gradient-echo pulse sequence. We determined ventilation volume and ventilation defect volume using an advanced semiautomatic segmentation algorithm and also quantified ventilation heterogeneity. RESULTS: There were no significant differences in total ventilation volume, ventilation defect volume, ventilation defect percentage, or mean ventilation heterogeneity (repeated-measures analysis of variance, P = .2116, P = .2825, P = .2871, and P = .7265, respectively) in the patients across the four scanning sessions. CONCLUSIONS: Our results indicate that total ventilation volume, ventilation defect volume, ventilation defect percentage, and mean ventilation heterogeneity as assessed by HP gas MRI in CF patients with stable health are reproducible over time. This repeatability and the technique's capability to provide noninvasive high-resolution data on regional lung function without ionizing radiation make (3)He MRI a potentially useful outcome measure for CF-related clinical trials.

Telaprevir-based treatment effects on hepatitis C virus in liver and blood.

UNLABELLED: Understanding hepatitis C virus (HCV) replication has been limited by access to serial samples of liver, the primary site of viral replication. Our understanding of how HCV replicates and develops drug-resistant variants in the liver is limited. We studied 15 patients chronically infected with genotype 1 HCV treated with telaprevir (TVR)/pegylated-interferon alpha/ribavirin. Hepatic fine needle aspiration was performed before treatment and at hour 10, days 4 and 15, and week 8 after initiation of antiviral therapy. We measured viral kinetics, resistance patterns, TVR concentrations, and host transcription profiles. All patients completed all protocol-defined procedures that were generally well tolerated. First-phase HCV decline (baseline/treatment day 4) was significantly slower in liver than in plasma (slope plasma: -0.29; liver, -0.009; P < 0.001), whereas second-phase decline (posttreatment days 4-15) did not differ between the two body compartments (-0.11 and -0.15, respectively; P = 0.1). TVR-resistant variants were detected in plasma, but not in liver (where only wild-type virus was detected). Based upon nonstructural protein 3 sequence analysis, no compartmentalization of viral populations was observed between plasma and liver compartments. Gene expression profiling revealed strong tissue-specific expression signatures. Human intrahepatic TVR concentration, measured for the first time, was lower, compared to plasma, on a gram per milliliter basis. We found moderate heterogeneity between HCV RNA levels from different intrahepatic sites, indicating differences in hepatic microenvironments. CONCLUSION: These data support an integrated model for HCV replication wherein the host hepatic milieu and innate immunity control the level of viral replication, and the early antiviral response observed in the plasma is predominantly driven by inhibition of hepatic high-level HCV replication sites.

Limited impact of IL28B genotype on response rates in telaprevir-treated patients with prior treatment failure.

BACKGROUND & AIMS: Nucleotide polymorphisms upstream of the interleukin 28B (IL28B) gene are strongly associated with hepatitis C virus (HCV) clearance in treatment-naïve patients treated with peginterferon/ribavirin (PegIFN/RBV). This subanalysis of the REALIZE study evaluated the impact of IL28B polymorphisms on sustained virologic response (SVR) in telaprevir-treated, HCV genotype 1-infected patients with prior PegIFN/RBV treatment failure. METHODS: Treatment-experienced patients were randomized to 12 weeks of telaprevir (750 mg every 8h) with/without a 4-week PegIFN/RBV lead-in, or placebo, each with PegIFN-α-2a (180 µg/week) and ribavirin (1000-1200 mg/day) for 48 weeks overall. Data from telaprevir arms were pooled. RESULTS: Eighty percent (527/662) of patients consented to genetic testing and were included. Similar proportions of patients had IL28B CC, CT and TT genotypes across treatment arms; baseline characteristics were generally well balanced. SVR rates were higher in the pooled telaprevir versus placebo group for all IL28B genotypes; CC: 79% versus 29%, respectively; CT: 60% versus 16%, respectively; TT: 61% versus 13%, respectively. Within each prior response category (relapse, partial or null response), SVR and viral breakthrough rates with telaprevir-based treatment were comparable across IL28B genotypes. IL28B genotype did not significantly affect SVR (2-step multivariate analyses; p >0.16 in pairwise comparison among CC, TT, and CT). Variations in rapid virologic response and relapse rates were noted in certain patient subgroups. CONCLUSIONS: Our findings suggest that IL28B genotype has a limited impact on SVR rates with telaprevir-based therapy in treatment-experienced patients. IL28B genotyping may have limited utility in the baseline evaluation of similar patients considered for telaprevir-based therapy.

Results of a phase IIa study of VX-809, an investigational CFTR corrector compound, in subjects with cystic fibrosis homozygous for the F508del-CFTR mutation.

BACKGROUND: VX-809, a cystic fibrosis transmembrane conductance regulator (CFTR) modulator, has been shown to increase the cell surface density of functional F508del-CFTR in vitro. METHODS: A randomised, double-blind, placebo-controlled study evaluated the safety, tolerability and pharmacodynamics of VX-809 in adult patients with cystic fibrosis (n=89) who were homozygous for the F508del-CFTR mutation. Subjects were randomised to one of four VX-809 28 day dose groups (25, 50, 100 and 200 mg) or matching placebo. RESULTS: The type and incidence of adverse events were similar among VX-809- and placebo-treated subjects. Respiratory events were the most commonly reported and led to discontinuation by one subject in each active treatment arm. Pharmacokinetic data supported a once-daily oral dosing regimen. Pharmacodynamic data suggested that VX-809 improved CFTR function in at least one organ (sweat gland). VX-809 reduced elevated sweat chloride values in a dose-dependent manner (p=0.0013) that was statistically significant in the 100 and 200 mg dose groups. There was no statistically significant improvement in CFTR function in the nasal epithelium as measured by nasal potential difference, nor were there statistically significant changes in lung function or patient-reported outcomes. No maturation of immature F508del-CFTR was detected in the subgroup that provided rectal biopsy specimens. CONCLUSIONS: In this study, VX-809 had a similar adverse event profile to placebo for 28 days in F508del-CFTR homozygous patients, and demonstrated biological activity with positive impact on CFTR function in the sweat gland. Additional data are needed to determine how improvements detected in CFTR function secondary to VX-809 in the sweat gland relate to those measurable in the respiratory tract and to long-term measures of clinical benefit. CLINICAL TRIAL NUMBER: NCT00865904.

Dynamic changes in HCV RNA levels and viral quasispecies in a patient with chronic hepatitis C after telaprevir-based treatment.

BACKGROUND: Telaprevir is a selective inhibitor of the hepatitis C virus NS3·4A serine protease. Treatment with telaprevir resulted in a rapid HCV-RNA decline in chronic hepatitis C genotype 1 patients. OBJECTIVES: To report the clinical and viral course of a patient treated with telaprevir in combination with pegylated interferon-alpha-2a and ribavirin in a Phase 2 clinical trial (PROVE3). STUDY DESIGN: This previous non-responder to interferon based therapy was treated for 40 weeks with a telaprevir, pegylated interferon alpha-2a, and ribavirin regimen. Viral sequencing and phylogenetic analysis were performed before, during and after therapy. RESULTS: The patient, a 54 years old male patient, experienced a viral relapse 4 weeks post-treatment and HCV-RNA levels continued to increase 14 weeks post-treatment (150,000 IU/mL). The viral population, which was wild type at baseline, consisted of only V36A variants at both of these post-treatment timepoints. Subsequently, this patient had a transient disappearance of HCV-RNA for more than 1 year in the absence of antiviral therapy. Thereafter, HCV-RNA reappeared again with a viral population consisting of only wild type virus. Phylogenetic analysis of NS3·4A corresponded with a viral population bottleneck resulting in changes in viral quasispecies. CONCLUSION: In this case report, significant viral load reductions resulted in a genetic bottleneck leading to a reduction of variability in the hepatitis C viral population. We hypothesize that the reduction in viral heterogeneity potentially led to a reduced viral capacity to adapt to a host immune response leading to a transient loss of detectable HCV-RNA.

Active-site residues of Escherichia coli DNA gyrase required in coupling ATP hydrolysis to DNA supercoiling and amino acid substitutions leading to novobiocin resistance.

DNA gyrase is a bacterial type II topoisomerase which couples the free energy of ATP hydrolysis to the introduction of negative supercoils into DNA. Amino acids in proximity to bound nonhydrolyzable ATP analog (AMP. PNP) or novobiocin in the gyrase B (GyrB) subunit crystal structures were examined for their roles in enzyme function and novobiocin resistance by site-directed mutagenesis. Purified Escherichia coli GyrB mutant proteins were complexed with the gyrase A subunit to form the functional A(2)B(2) gyrase enzyme. Mutant proteins with alanine substitutions at residues E42, N46, E50, D73, R76, G77, and I78 had reduced or no detectable ATPase activity, indicating a role for these residues in ATP hydrolysis. Interestingly, GyrB proteins with P79A and K103A substitutions retained significant levels of ATPase activity yet demonstrated no DNA supercoiling activity, even with 40-fold more enzyme than the wild-type enzyme, suggesting that these amino acid side chains have a role in the coupling of the two activities. All enzymes relaxed supercoiled DNA to the same extent as the wild-type enzyme did, implying that only ATP-dependent reactions were affected. Mutant genes were examined in vivo for their abilities to complement a temperature-sensitive E. coli gyrB mutant, and the activities correlated well with the in vitro activities. We show that the known R136 novobiocin resistance mutations bestow a significant loss of inhibitor potency in the ATPase assay. Four new residues (D73, G77, I78, and T165) that, when changed to the appropriate amino acid, result in both significant levels of novobiocin resistance and maintain in vivo function were identified in E. coli.