The discovery of a novel HCV GT8 confirms the circulation of this newly identified lineage in the human population.

Currently, there are no interferon-free treatments available for hepatitis C virus (HCV)-infected patients younger than 12 years. We evaluated the safety and effectiveness of the all-oral regimen ledipasvir-sofosbuvir ± ribavirin in HCV-infected children aged 6 to<12 years. In an open-label study, patients aged 6 to <12 years received ledipasvir 45 mg-sofosbuvir 200 mg as two fixed-dose combination tablets 22.5/100 mg once daily, with or without ribavirin, for 12 or 24 weeks, depending on HCV genotype and cirrhosis status. The primary efficacy endpoint was sustained virologic response 12 weeks after therapy (SVR12). Twelve patients underwent intensive pharmacokinetic sampling to confirm the appropriateness of the ledipasvir and sofosbuvir dosages. Ninety-two patients were enrolled (88 genotype 1, 2 genotype 3, and 2 genotype 4), with a median age of 9 years (range, 6-11). Most were perinatally infected (97%) and treatment-naive (78%). Two were confirmed to have cirrhosis, while the degree of fibrosis was unknown in 55 patients. The overall SVR12 rate was 99% (91/92; 95% confidence interval, 94%-100%). The single patient not reaching SVR relapsed 4 weeks after completing 12 weeks of treatment. The most common adverse events were headache and pyrexia. One patient had three serious adverse events, which were considered to be not related to study treatment: tooth abscess, abdominal pain, and gastroenteritis. The area under the concentration-time curve and maximum concentration values for sofosbuvir, its primary metabolite GS-331007, and ledipasvir were within predefined pharmacokinetic equivalence boundaries (50%-200%) compared to values in adults in phase 2/3 of the ledipasvir and sofosbuvir studies. Conclusion: Ledipasvir-sofosbuvir was well tolerated and highly effective in children 6 to <12 years old with chronic HCV.

For children under 12 years of age who have chronic hepatitis C virus (HCV) infection, there are currently no approved treatments with direct‐acting antiviral agents. We therefore evaluated the safety and efficacy of ledipasvir‐sofosbuvir in HCV‐infected children aged 3 to <6 years. In an open‐label study, patients 3 to <6 years old chronically infected with HCV genotype 1 (n = 33) or 4 (n = 1) received weight‐based doses of combined ledipasvir‐sofosbuvir as granules (33.75 mg/150 mg for weights <17 kg or 45 mg/200 mg for weights ≥17 kg) for 12 weeks. The primary endpoint was sustained virological response 12 weeks after treatment (SVR12). For the first 14 patients, intensive pharmacokinetic sampling was done on day 10 of treatment. All patients had been infected through perinatal transmission and were treatment naïve. No patients had known cirrhosis. Ten patients (29%) weighed <17 kg. SVR12 was achieved in 97% of patients (33 of 34); the patient who did not achieve SVR12 was 3 years old and discontinued treatment after 5 days because of an adverse event “abnormal drug taste.” The most common adverse events were vomiting (24% of patients), cough (21%), and pyrexia (21%). No patients experienced a serious adverse event. Intensive pharmacokinetic analysis of 13 patients for whom data were evaluable confirmed that the doses selected were appropriate. Conclusion: Ledipasvir‐sofosbuvir was well tolerated and highly effective in children 3 to <6 years old with chronic HCV infection.

Background Hepatitis C virus (HCV) is currently classified into 8 genotypes and 86 subtypes. The objective of this study was to characterize novel HCV subtypes and to investigate the impact of subtypes on treatment outcome. Methods Full-genome sequencing was performed on HCV plasma samples with &lt;85% sequence homology of NS3, NS5A, and/or NS5B to HCV genotype (GT) 1–8 reference strains. Results A total of 14 653 patients with GT1–6 HCV infection were enrolled in clinical studies of sofosbuvir-based regimens. For the majority of the patients, a specific subtype could be assigned based on a close genetic relationship to previously described subtypes. However, for 19 patients, novel subtypes were identified with &lt;85% homology compared with previously described subtypes. These novel subtypes had the following genotypes: 9 in GT2, 5 in GT4, 2 in GT6, and 1 each in GT1, GT3, and GT5. Despite the presence of polymorphisms at resistance-associated substitution positions, 18 of the 19 patients treated with sofosbuvir-containing therapy achieved SVR12. Conclusions Nineteen novel HCV subtypes were identified, suggesting an even greater genetic diversity of HCV subtypes than previously recognized.

Currently, the only approved hepatitis C virus (HCV) treatment for children aged <12 years is pegylated interferon plus ribavirin. In an open‐label study, we evaluated the safety and efficacy of sofosbuvir plus ribavirin for 12 weeks in children aged 3 to <12 years chronically infected with genotype 2 or for 24 weeks in patients with genotype 3. Patients aged 3 to <6 years weighing <17 kg received sofosbuvir 150 mg, and patients aged 3 to <6 years weighing ≥17 kg and all patients aged 6 to <12 years received sofosbuvir 200 mg once daily. Intensive pharmacokinetic sampling conducted in each age group confirmed the appropriateness of sofosbuvir doses. For all patients, ribavirin dosing was determined by baseline weight (up to 1,400 mg/day, two divided doses). The primary efficacy endpoint was sustained virologic response 12 weeks after therapy (SVR12). Fifty‐four patients were enrolled (41 aged 6 to <12 years and 13 aged 3 to <6 years). Most were treatment naïve (98%) and infected perinatally (94%). All but one patient achieved SVR12 (53/54, 98%; 95% confidence interval, 90%‐100%). The patient who did not achieve SVR12 was a 4‐year‐old who discontinued treatment after 3 days because of “abnormal drug taste.” The most commonly reported adverse events in patients aged 6 to <12 years were vomiting (32%) and headache (29%), and those in patients aged 3 to <6 years were vomiting (46%) and diarrhea (39%). One 3‐year‐old patient had a serious adverse event of accidental ribavirin overdose requiring hospitalization for monitoring; this patient completed treatment and achieved SVR12. Conclusion: Sofosbuvir plus ribavirin was well tolerated and highly effective in children aged 3 to <12 years with chronic HCV genotype 2 or 3 infection.

HCV genotype 4 (GT4) has often been overlooked in drug development, even though it infects ~20 million people worldwide. Ledipasvir/sofosbuvir and sofosbuvir/velpatasvir were highly efficacious in GT4 HCV-infected patients from GS-US-337-1119 and GS-US-342-1138. Here, we characterize the resistance profile of ledipasvir (LDV) and velpatasvir (VEL) in patients with GT4 HCV infection. NS5A deep-sequencing was performed for 454 patients infected with HCV GT4 at baseline, including 44 patients enrolled in GS-US-337-1119 and 116 patients enrolled in GS-US-342-1138, and at relapse for patients with virologic failure. LDV and VEL susceptibilities of 56 patient isolates were determined. In GS-US-337-1119, SVR12 rates were 100% for all subtypes except 4b and 4r. Phenotypic assessment of 56 HCV NS5A patient isolates from various GT4 subtypes indicated that LDV had high potency for the common subtypes 4a/d, and subtypes 4c/f/k/l/m/n/o/p/r/t despite the presence of resistance-associated substitutions (RASs). For the rare GT4b, LDV median EC was higher, but with a broad range of individual values. Importantly, all GT4b isolates tested had 2-4 NS5A RASs, some including Y93H. Similarly, the 2 GT4r infected patients who had virologic relapse had rare triple RASs. Reversion of these substitutions to the consensus residue significantly increased LDV susceptibility. In GS-US-342-1138, all patients achieved SVR12, regardless of their subtype or presence of RASs. In vitro data confirmed that VEL is potent against all GT4 isolates tested. LDV and VEL are potent antiviral drugs, estimated to be effective against >95% and >99%, respectively, of GT4 HCV isolates.

Tenofovir alafenamide (TAF) has shown equivalent efficacy and improved safety profiles for patients with chronic hepatitis B (CHB) compared to tenofovir disoproxil fumarate (TDF). However, limited data are available for its resistance profiles. In two clinical trials, 1,298 hepatitis E antigen-positive and -negative patients with CHB were randomized 2:1 and treated with TAF ( = 866) or TDF ( = 432). Baseline nucleos(t)ide analog resistance substitutions in HBV polymerase/reverse transcriptase (Pol/RT) were assessed using INNO-LiPA Multi-DR v2/v3. Resistance surveillance was conducted for patients with viremia (HBV DNA ≥ 69IU/ml) by HBV Pol/RT sequencing at week 96 or at discontinuation. phenotypic analysis was performed for patients with conserved site substitutions or virologic breakthrough while adherent to the study drug. At baseline, the majority of patients harbored virus with wild-type Pol/RT (89.2%), with 10.8% harboring resistance associated mutations. A similar percentage of patients in the TAF or TDF groups qualified for sequence analysis through week 96 (TAF, 11.1%; TDF, 10.9%). Of these, a small percentage of patients experienced virologic breakthrough (TAF, 2.8%; TDF, 3.2%) that was often associated with drug nonadherence (TAF, 30%; TDF, 50%). Across treatment groups, 132 patients qualified for sequence analysis through week 96, with nearly half having no sequence changes from baseline (43.2%). Most sequence changes occurred at polymorphic positions, and no isolates showed a reduction in susceptibility After 96 weeks, the proportion of patients achieving virus suppression (HBV DNA < 69 IU/ml) was similar across treatment groups, and no substitutions associated with resistance to TAF or TDF were detected. (These studies have been registered at ClinicalTrials.gov under identifiers NCT01940471 and NCT01940341.).

White lupin (Lupinus albus L.) is considered a model system for understanding plant acclimation to nutrient deficiency. It acclimates to phosphorus (P) and iron (Fe) deficiency by the development of short, densely clustered lateral roots called proteoid (or cluster) roots; proteoid-root development is further influenced by nitrogen (N) supply. In an effort to better understand proteoid root function under various nutrient deficiencies, we used nylon filter arrays to analyze 2,102 expressed sequence tags (ESTs) from proteoid roots of P-deficient white lupin. These have been previously analyzed for up-regulation in −P proteoid roots, and were here analyzed for upregulation in proteoid roots of N-deprived plants. We identified a total of 19 genes that displayed upregulation in proteoid roots under both P and N Plant Soil (2010) 334:137-150 deprivation. One of these genes showed homology to putative formamidases. The corresponding open reading frame was cloned, overexpressed in E. coli, and the encoded protein was purified; functional characterization of the recombinant protein confirmed formamidase activity. Though many homologues of bacterial and fungal formamidases have been identified in plants, to our knowledge, this is the first report of a functional characterization of a plant formamidase.