Glecaprevir/Pibrentasvir Treatment in Liver or Kidney Transplant Patients With Hepatitis C Virus Infection

Well-tolerated, ribavirin-free, pangenotypic hepatitis C virus (HCV) treatments for transplant recipients remain a high priority. Once-daily glecaprevir/pibrentasvir demonstrates high rates of sustained virologic response at 12 weeks posttreatment (SVR12) across all major HCV genotypes (GTs). This trial evaluated the safety and efficacy of glecaprevir/pibrentasvir for patients with chronic HCV GT1-6 infection who had received a liver or kidney transplant. MAGELLAN-2 was a phase 3, open-label trial conducted in patients who were ≥3 months posttransplant. Patients without cirrhosis who were HCV treatment-naive (GT1-6) or treatment-experienced (GT1, 2, 4-6; with interferon-based therapy with or without sofosbuvir, or sofosbuvir plus ribavirin) received glecaprevir/pibrentasvir (300/120 mg) once daily for 12 weeks. The primary endpoint compared the percentage of patients receiving glecaprevir/pibrentasvir with SVR12 to a historic SVR12 rate based on the standard of care. Safety of glecaprevir/pibrentasvir was assessed. In total, 80 liver transplant and 20 kidney transplant patients participated in the trial. Most patients had no or minimal fibrosis (80% had fibrosis scores F0-F1) and were infected with HCV GT1 (57%) or GT3 (24%). The overall SVR12 was 98% (n/N = 98/100; 95% confidence interval, 95.3%-100%), which exceeded the prespecified historic standard-of-care SVR12 threshold of 94%. One patient experienced virologic failure. One patient discontinued because of an adverse event considered to be unrelated to treatment; this patient achieved SVR12. Adverse events were mostly mild in severity, and laboratory abnormalities were infrequent. CONCLUSION: Once-daily glecaprevir/pibrentasvir for 12 weeks is a well-tolerated and efficacious, ribavirin-free treatment for patients with chronic HCV GT1-6 infection who have received a liver or kidney transplant. (ClinicalTrials.gov NCT02692703.) (Hepatology 2018; 00:000-000)

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Efficient background subtraction for real-time tracking in embedded camera networks

Background subtraction is often the first step of many computer vision applications. For a background subtraction method to be useful in embedded camera networks, it must be both accurate and computationally efficient because of the resource constraints on embedded platforms. This makes many traditional background subtraction algorithms unsuitable for embedded platforms because they use complex statistical models to handle subtle illumination changes. These models make them accurate but the computational requirement of these complex models is often too high for embedded platforms. In this paper, we propose a new background subtraction method which is both accurate and computational efficient. The key idea is to use compressive sensing to reduce the dimensionality of the data while retaining most of the information. By using multiple datasets, we show that the accuracy of our proposed background subtraction method is comparable to that of the traditional background subtraction methods. Moreover, real implementation on an embedded camera platform shows that our proposed method is at least 5 times faster, and consumes significantly less energy and memory resources than the conventional approaches. Finally, we demonstrated the feasibility of the proposed method by the implementation and evaluation of an end-to-end real-time embedded camera network target tracking application

ABT-450, ritonavir, ombitasvir, and dasabuvir achieves 97% and 100% sustained virologic response with or without ribavirin in treatment-experienced patients with HCV genotype 1b infection

BACKGROUND & AIMS The interferon-free regimen of ABT-450 (a protease inhibitor), ritonavir, ombitasvir (an NS5A inhibitor), dasabuvir (a non-nucleoside polymerase inhibitor), and ribavirin has shown efficacy in patients with hepatitis C virus (HCV) genotype 1b infection-the most prevalent subgenotype worldwide. We evaluated whether ribavirin is necessary for ABT-450, ritonavir, ombitasvir, and dasabuvir to produce high rates of sustained virologic response (SVR) in these patients. METHODS We performed a multicenter, open-label, phase 3 trial of 179 patients with HCV genotype 1b infection, without cirrhosis, previously treated with peginterferon and ribavirin. Patients were assigned randomly (1:1) to groups given ABT-450, ritonavir, ombitasvir, and dasabuvir, with ribavirin (group 1) or without (group 2) for 12 weeks. The primary end point was SVR 12 weeks after treatment (SVR12). We assessed the noninferiority of this regimen to the rate of response reported (64%) for a similar population treated with telaprevir, peginterferon, and ribavirin. RESULTS Groups 1 and 2 each had high rates of SVR12, which were noninferior to the reported rate of response to the combination of telaprevir, peginterferon, and ribavirin (group 1: 96.6%; 95% confidence interval, 92.8%-100%; and group 2: 100%; 95% confidence interval, 95.9%-100%). The rate of response in group 2 was noninferior to that of group 1. No virologic failure occurred during the study. Two patients (1.1%) discontinued the study owing to adverse events, both in group 1. The most common adverse events in groups 1 and 2 were fatigue (31.9% vs 15.8%) and headache (24.2% vs 23.2%), respectively. Decreases in hemoglobin level to less than the lower limit of normal were more frequent in group 1 (42.0% vs 5.5% in group 2; P < .001), although only 2 patients had hemoglobin levels less than 10 g/dL. CONCLUSIONS The interferon-free regimen of ABT-450, ritonavir, ombitasvir, and dasabuvir, with or without ribavirin, produces a high rate of SVR12 in treatment-experienced patients with HCV genotype 1b infection. Both regimens are well tolerated, as shown by the low rate of discontinuations and generally mild adverse events. ClinicalTrials.gov number: NCT01674725

Treatment of monogenic and digenic dominant genetic hearing loss by CRISPR-Cas9 ribonucleoprotein delivery in vivo

Abstract Mutations in Atp2b2, an outer hair cell gene, cause dominant hearing loss in humans. Using a mouse model Atp2b2 Obl/+, with a dominant hearing loss mutation (Oblivion), we show that liposome-mediated in vivo delivery of CRISPR-Cas9 ribonucleoprotein complexes leads to specific editing of the Obl allele. Large deletions encompassing the Obl locus and indels were identified as the result of editing. In vivo genome editing promotes outer hair cell survival and restores their function, leading to hearing recovery. We further show that in a double-dominant mutant mouse model, in which the Tmc1 Beethoven mutation and the Atp2b2 Oblivion mutation cause digenic genetic hearing loss, Cas9/sgRNA delivery targeting both mutations leads to partial hearing recovery. These findings suggest that liposome-RNP delivery can be used as a strategy to recover hearing with dominant mutations in OHC genes and with digenic mutations in the auditory hair cells, potentially expanding therapeutics of gene editing to treat hearing loss