Daclatasvir–sofosbuvir combination therapy with or without ribavirin for hepatitis C virus infection: from the clinical trials to real life

Stanislas Pol, Marion Corouge, Anaïs Vallet-Pichard Université Paris Descartes, Liver Department, Assistance Publique Hôpitaux de Paris, Cochin Hospital, French Institute of Health and Medical Research UMS20, Institut Pasteur, Paris, France Abstract: The treatment of hepatitis C virus has changed dramatically with the rapid advent of numerous new antiviral agents, including direct-acting antivirals and agents with non-viral targets (cyclophilin inhibitors, interferon-lambda, vaccine therapy). Given the better safety profile and high antiviral potency of direct-acting antivirals, their combination in interferon-free oral regimens is becoming the standard of care for hepatitis C virus infection, tailored to individual patients according to the degree of disease progression (fibrosis), hepatitis C virus genotype and subtype, resistance profile, and prior therapeutic history. Results from clinical studies as well as preliminary real-life data regarding the combination of sofosbuvir (a nucleotide polymerase inhibitor) and daclatasvir, a first-in-class NS5A replication complex inhibitor, demonstrate that it is one of the most promising antiviral therapies, with once-daily oral dosing, a low pill burden, good tolerability, and limited drug–drug interactions, in addition to high antiviral potency, with >90% sustained virologic response rates. This combination has high pangenotypic antiviral potency regardless of the severity and patient characteristics. The combination of sofosbuvir and an NS5A inhibitor with ribavirin for 12 weeks appears to be a very good further treatment option in both cirrhotic and treatment-experienced patients whatever the stage of fibrosis. Keywords: hepatitis C virus, direct-acting antivirals, sofosbuvir, daclatasvi

Early postnatal development of corpus callosum and corticospinal white matter assessed with quantitative tractography.

International audienceBACKGROUND AND PURPOSE: The early postnatal period is perhaps the most dynamic phase of white matter development. We hypothesized that the early postnatal development of the corpus callosum and corticospinal tracts could be studied in unsedated healthy neonates by using novel approaches to diffusion tensor imaging (DTI) and quantitative tractography. MATERIALS AND METHODS: Isotropic 2 x 2 x 2 mm(3) DTI and structural images were acquired from 47 healthy neonates. DTI and structural images were coregistered and fractional anisotropy (FA), mean diffusivity (MD), and normalized T1-weighted (T1W) and T2-weighted (T2W) signal intensities were determined in central midline and peripheral cortical regions of the white matter tracts of the genu and splenium of the corpus callosum and the central midbrain and peripheral cortical regions of the corticospinal tracts by using quantitative tractography. RESULTS: We observed that central regions exhibited lower MD, higher FA values, higher T1W intensity, and lower T2W intensity than peripheral cortical regions. As expected, MD decreased, FA increased, and T2W signal intensity decreased with increasing age in the genu and corticospinal tract, whereas there was no significant change in T1W signal intensity. The central midline region of the splenium fiber tract has a unique pattern, with no change in MD, FA, or T2W signal intensity with age, suggesting different growth trajectory compared with the other tracts. FA seems to be more dependent on tract organization, whereas MD seems to be more sensitive to myelination. CONCLUSIONS: Our novel approach may detect small regional differences and age-related changes in the corpus callosum and corticospinal white matter tracts in unsedated healthy neonates and may be used for future studies of pediatric brain disorders that affect developing white matter

Obtaining representative core streamlines for white matter tractometry of the human brain

Diffusion MRI infers information about the micro-structural architecture of the brain by probing the diffusion of water molecules. The process of virtually reconstructing brain pathways based on these measurements is called tractography. Various metrics can be mapped onto pathways to study their micro-structural properties. Tractometry is an along-tract profiling technique that often requires the extraction of a representative streamline for a given bundle. This is traditionally computed by local averaging of the spatial coordinates of the vertices, and constructing a single streamline through those averages. However, the resulting streamline can end up being highly non-representative of the shape of the individual streamlines forming the bundle. In particular, this occurs when there is variation in the topology of streamlines within a bundle (e.g., differences in length, shape or branching). We propose an envelope-based method to compute a representative streamline that is robust to these individual differences. We demonstrate that this method produces a more representative core streamline, which in turn should lead to more reliable and interpretable tractometry analyses