Protein-Ribofuranosyl Interactions Activate Orotidine 5'-Monophosphate Decarboxylase for Catalysis.

The role of a global, substrate-driven, enzyme conformational change in enabling the extraordinarily large rate acceleration for orotidine 5'-monophosphate decarboxylase (OMPDC)-catalyzed decarboxylation of orotidine 5'-monophosphate (OMP) is examined in experiments that focus on the interactions between OMPDC and the ribosyl hydroxyl groups of OMP. The D37 and T100' side chains of OMPDC interact, respectively, with the C-3' and C-2' hydroxyl groups of enzyme-bound OMP. D37G and T100'A substitutions result in 1.4 kcal/mol increases in the activation barrier ΔG⧧ for catalysis of decarboxylation of the phosphodianion-truncated substrate 1-(ß-d-erythrofuranosyl)orotic acid (EO) but result in larger 2.1-2.9 kcal/mol increases in ΔG⧧ for decarboxylation of OMP and for phosphite dianion-activated decarboxylation of EO. This shows that these substitutions reduce transition-state stabilization by the Q215, Y217, and R235 side chains at the dianion binding site. The D37G and T100'A substitutions result in <1.0 kcal/mol increases in ΔG⧧ for activation of OMPDC-catalyzed decarboxylation of the phosphoribofuranosyl-truncated substrate FO by phosphite dianions. Experiments to probe the effect of D37 and T100' substitutions on the kinetic parameters for d-glycerol 3-phosphate and d-erythritol 4-phosphate activators of OMPDC-catalyzed decarboxylation of FO show that ΔG⧧ for sugar phosphate-activated reactions is increased by ca. 2.5 kcal/mol for each -OH interaction eliminated by D37G or T100'A substitutions. We conclude that the interactions between the D37 and T100' side chains and ribosyl or ribosyl-like hydroxyl groups are utilized to activate OMPDC for catalysis of decarboxylation of OMP, EO, and FO.

Single Diastereomers of the Clinical Anticancer ProTide Agents NUC-1031 and NUC-3373 Preferentially Target Cancer Stem Cells In Vitro.

A 3'-protected route toward the synthesis of the diastereomers of clinically active ProTides, NUC-1031 and NUC-3373, is described. The in vitro cytotoxic activities of the individual diastereomers were found to be similar to their diastereomeric mixtures. In the KG1a cell line, NUC-1031 and NUC-3373 have preferential cytotoxic effects on leukemic stem cells (LSCs). These effects were not diastereomer-specific and were not observed with the parental nucleoside analogues gemcitabine and FUDR, respectively. In addition, NUC-1031 preferentially targeted LSCs in primary AML samples and cancer stem cells in the prostate cancer cell line, LNCaP. Although the mechanism for this remains incompletely resolved, NUC-1031-treated cells showed increased levels of triphosphate in both LSC and bulk tumor fractions. As ProTides are not dependent on nucleoside transporters, it seems possible that the LSC targeting observed with ProTides may be caused, at least in part, by preferential accumulation of metabolized nucleos(t)ide analogues.

Clinical effectiveness of pharmacist-led versus conventionally delivered antiviral treatment for hepatitis C virus in patients receiving opioid substitution therapy: a pragmatic, cluster-randomised trial.

BACKGROUND: Highly effective direct-acting antiviral drugs provide the opportunity to eliminate hepatitis C virus (HCV) infection, but established pathways can be ineffective. We aimed to examine whether a community pharmacy care pathway increased treatment uptake, treatment completion, and cure rates for people receiving opioid substitution therapy, compared with conventional care. METHODS: This cluster-randomised trial was done in Scottish community pharmacies. Before participants were recruited, pharmacies were randomly assigned (1:1) to refer patients with evidence of HCV antibodies to conventional care or offered them care in the pharmacy (pharmacist-led care). Pharmacies were stratified by location. All pharmacies were trained to offer dried blood spot testing. All eligible participants had received opioid substitution therapy for approximately 3 months, and those eligible to receive treatment in the pharmacist-led care pathway were HCV PCR positive, were infected with HCV genotype 1 or 3, and were willing to have a pharmacist supervise their antiviral drug administration. Neither pharmacists nor patients were masked to treatment allocation. In both groups, assessment blood samples were taken, infection with HCV was confirmed, and daily oral ledipasvir-sofosbuvir (90 mg ledipasivir plus 400 mg sofosbuvir) for 8 weeks for genotype 1 or daily oral sofosbuvir (400 mg) plus oral daclatasvir (60 mg) for 12 weeks for genotype 3 was prescribed by a nurse (conventional care group) or pharmacist (pharmacist-led care group). In the conventional care group, the patient received care at a treatment centre. Once prescribed, medication in both groups was delivered as daily modified directly observed therapy alongside opioid substitution therapy in the participants' pharmacy where treatment was observed on 6 days per week. The primary outcome was the number of patients with sustained virological response 12 weeks after completion of treatment (SVR12) as a proportion of the number of people receiving opioid substitution therapy at participating pharmacies. Participants were monitored at each visit for nausea and fatigue; other adverse events were recorded as free text. Secondary outcomes compared key points on treatment pathway between the two groups. These key points were the proportion of patients having dry blood spot testing, the proportion of patients initiating HCV treatment, the proportion of patients completing the 8 or 12 week HCV course of treatment, and the proportion of patients with sustained virological response at 12 months. This study is registered with ClinicalTrials.gov, NCT02706223. FINDINGS: 56 pharmacies were randomly assigned (28 to each group; one pharmacy withdrew from the conventional care group). The 55 participating pharmacies included 2718 patients receiving opioid substitution therapy (1365 in the pharmacist-led care group and 1353 in the conventional care group). More patients met the primary endpoint of SVR12 in the pharmacist-led care group (98 [7%] of 1365) than in the conventional care group (43 [3%] of 1353; odds ratio 2·375, 95% CI 1·555-3·628, p<0·0001). More users of opioid substitution therapy in the pharmacist-led care group versus the conventional care group agreed to dry blood spot testing (245 [18%] of 1365 vs 145 [11%] of 1353, 2·292, 0·968-5·427, p=0·059); initiated treatment (112 [8%] of 1365 vs 61 [4%] of 1353, 1·889, 1·276-2·789, p=0·0015) and completed treatment (108 [8%] of 1365 vs 58 [4%] of 1353, 1·928, 1·321-2·813, p=0·0007). The data for sustained virological response at 12 months are not reported in this study: patients remain in follow-up for this outcome. No serious adverse events were recorded. INTERPRETATION: Using pharmacists to deliver an HCV care pathway made testing and treatment more accessible for patients, improved engagement, and maintained high treatment success rates. The use of this pathway could be a key part of an integrated and effective approach to HCV elimination at a community level. FUNDING: Partnership between the Scottish Government, Gilead Sciences, and Bristol-Myers Squib.

Sofosbuvir plus ribavirin and sofosbuvir plus ledipasvir in patients with genotype 1 or 3 hepatitis C virus and severe renal impairment: a multicentre, phase 2b, non-randomised, open-label study.

BACKGROUND: There is a medical need for highly effective, safe, and well tolerated treatments for patients infected with hepatitis C virus (HCV) with severe renal impairment. We investigated the safety and efficacy of sofosbuvir with ribavirin or ledipasvir combined with sofosbuvir in a prospective study of patients with genotype 1 or 3 HCV infection and stage 4-5 chronic kidney disease (creatinine clearance by Cockcroft-Gault ≤30 mL/min) who were not on dialysis. METHODS: This phase 2b, open-label, non-randomised, multicentre study in the USA and New Zealand investigated three sequentially enrolled cohorts of patients. Patients were recruited from ten hospitals and clinical research centres and were included if they had genotype 1 or 3 HCV infection, a creatinine clearance less than or equal to 30 mL/min, and were not on dialysis. In cohorts 1 and 2, patients received sofosbuvir (200 mg in cohort 1 and 400 mg in cohort 2) plus ribavirin 200 mg once per day for 24 weeks. In cohort 3, 18 patients received ledipasvir combined with sofosbuvir (90 mg ledipasvir and 400 mg sofosbuvir) once per day for 12 weeks. The primary efficacy endpoint was the proportion of patients achieving sustained virological response 12 weeks after the end of treatment (SVR12). Safety and pharmacokinetic data were also collected. The trial is registered with ClinicalTrials.gov, number NCT01958281, and is completed. FINDINGS: This study was done between Oct 7, 2013, and Oct 29, 2017. In the sofosbuvir plus ribavirin cohorts, 32 patients were screened, of whom 20 were enrolled and assessed for efficacy and safety (ten patients in each cohort). In the ledipasvir plus sofosbuvir cohort, 33 patients were screened, of whom 18 were enrolled and assessed for treatment efficacy and safety. Four (40%, 95% CI 12-74) of ten patients in cohort 1 and six (60%, 26-88) of ten patients in cohort 2 achieved SVR12. All 18 (100%, 82-100) patients in cohort 3 achieved SVR12. Adverse events were mostly mild or moderate in severity. The most commonly reported adverse events overall were headache (eight [21%] of 38 patients), anaemia (seven [18%] of 38 patients), and fatigue (six [16%] of 38 patients). Eight patients had serious adverse events, none of which were treatment related. There were no treatment-related cardiac events or clinically significant changes in echocardiographic parameters or creatinine clearance by Cockcroft-Gault. INTERPRETATION: In this phase 2b study, ledipasvir combined with sofosbuvir for 12 weeks was safe and effective in patients with genotype 1 HCV infection and stage 4-5 chronic kidney disease who were not on dialysis. FUNDING: Gilead Sciences.

Effectiveness of sofosbuvir based direct-acting antiviral regimens for chronic hepatitis C virus genotype 6 patients: Real-world experience in Vietnam.

BACKGROUND: Hepatitis C virus (HCV) genotype 6 is the commonest cause of chronic hepatitis C infection in much of southeast Asia, but data on the effectiveness of direct-acting antiviral agents (DAAs) against this genotype are limited. We conducted a retrospective cohort study of patients attending the Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam, to define the effectiveness of DAAs in the treatment of chronic HCV genotype 6 in actual practice. METHODS: We included all patients with genotype 6 infections attending our hospital between March 2016 and October 2017 who received treatment with sofosbuvir-based DAA treatment regimens, and compared their responses with those with genotype 1 infections. RESULTS: 1758 patients (1148 genotype 6, 65.4%; 610 genotype 1, 34.6%) were analyzed. The majority of patients (1480, 84.2%) received sofosbuvir/ledipasvir (SOF/LDV) ± ribavirin (RBV); 278 (15.8%) received sofosbuvir/Daclatasvir (SOF/DCV) ± RBV. The median age of the patients was 57 years, (interquartile range (IQR) 46-64 years) The baseline HCV viral load (log IU/ml) was significantly higher in patients infected with genotype 6 compared with those infected with genotype 1 (6.8, 5.3-6.6 versus 6.3, 5.3-6.5 log10 IU/ml, p = <0.001, Mann Whitney U test). A sustained virological response (SVR), defined as an undetectable viral load measured between 12 and 24 weeks after completing treatment, and indicating cure, was seen in 97.3% (1711/1758) of patients. Treatment failure, defined as HCV viral load ≥15 IU/ml ≥12 weeks after completing treatment appeared to be more frequent in patients infected with genotype 6 virus (3.2%, 37/1148) than in those infected with genotype 1 (1.7%, 10/610), p = 0.050 chi-squared test). We found no evidence that patient's age, gender, liver cirrhosis, diabetes, HBV or HIV coinfection, prior treatment failure with pegylated interferon therapy, body mass index (BMI), aspartate aminotransferase to platelet ratio index (APRI), or fibrosis 4 (FIB-4) index were associated with treatment failure. CONCLUSIONS: Our study suggests that patients with HCV genotype 6 infection in Vietnam may respond less well to treatment with sofosbuvir based DAAs than patients with genotype 1 infections. Further studies are needed to confirm this observation and to define whether it is driven by genotype-specific mutations.

English hepatitis C registry data show high response rates to directly acting anti-virals, even if treatment is not completed.

BACKGROUND: In England, choice of hepatitis C therapy is determined by national contracts that change with time, facilitating comparisons between different regimens. England has a diverse population with hepatitis C including large proportions of uncommon viral genotypes. AIM: To evaluate efficacy of directly acting anti-viral treatments for hepatitis C in England using real-world data from the national treatment registry. METHODS: Sustained virological response (SVR) rates 12 weeks after treatment completion for patients treated between 2014 and August 2018 who attended for SVR tests were analysed in univariate subgroups using Chi-squared tests. Multivariate models were constructed with clinically relevant variables to determine predictors of SVR and evaluate the impact of treatment regimens. RESULTS: SVR data were available on 14,603 treated patients. The overall SVR rate was 95.59% [95% CI 95.25%-95.91%]. Multivariable regression modelling in patients with genotype 1 infection showed that the odds of SVR with elbasvir/grazoprevir were higher than for those treated with sofosbuvir/ledipasvir (OR 1.891, 95% CI 1.072-3.336, P = 0.028). For genotype 3, we found no significant difference between any of the treatment regimens. Patients who completed at least one third of the planned treatment duration achieved SVR rates in excess of 80%. CONCLUSIONS: All of the currently licensed hepatitis C direct-acting anti-viral regimens had similar efficacy (>95%) in an unselected population. Noncompletion of planned treatment duration still resulted in over 80% SVR rates provided that more than one third of treatment was completed.

Orotidine 5'-Monophosphate Decarboxylase: The Operation of Active Site Chains Within and Across Protein Subunits.

The D37 and T100' side chains of orotidine 5'-monophosphate decarboxylase (OMPDC) interact with the C-3' and C-2' ribosyl hydroxyl groups, respectively, of the bound substrate. We compare the intra-subunit interactions of D37 with the inter-subunit interactions of T100' by determining the effects of the D37G, D37A, T100'G, and T100'A substitutions on the following: (a) kcat and kcat/Km values for the OMPDC-catalyzed decarboxylations of OMP and 5-fluoroorotidine 5'-monophosphate (FOMP) and (b) the stability of dimeric OMPDC relative to the monomer. The D37G and T100'A substitutions resulted in 2 kcal mol-1 increases in ΔG† for kcat/Km for the decarboxylation of OMP, while the D37A and T100'G substitutions resulted in larger 4 and 5 kcal mol-1 increases, respectively, in ΔG†. The D37G and T100'A substitutions both resulted in smaller 2 kcal mol-1 decreases in ΔG† for the decarboxylation of FOMP compared to that of OMP. These results show that the D37G and T100'A substitutions affect the barrier to the chemical decarboxylation step while the D37A and T100'G substitutions also affect the barrier to a slow, ligand-driven enzyme conformational change. Substrate binding induces the movement of an α-helix (G'98-S'106) toward the substrate C-2' ribosyl hydroxy bound at the main subunit. The T100'G substitution destabilizes the enzyme dimer by 3.5 kcal mol-1 compared to the monomer, which is consistent with the known destabilization of α-helices by the internal Gly side chains [Serrano, L., et al. (1992) Nature, 356, 453-455]. We propose that the T100'G substitution weakens the α-helical contacts at the dimer interface, which results in a decrease in the dimer stability and an increase in the barrier to the ligand-driven conformational change.

Hepatitis C virus treatment response to ledipasvir/sofosbuvir among patients coinfected with HIV and HCV: Real world data in a black population.

Treatment of hepatitis C virus (HCV) infection for patients with human immunodeficiency virus (HIV) has improved with direct acting antivirals. However, outcomes among Black persons treated with ledipasvir/sofosbuvir (LDV/SOF) may be inferior to non-Blacks. We assessed responses to LDV/SOF in a cohort of Black HIV/HCV coinfected persons.Retrospective chart reviews were conducted for Black, genotype 1 (GT1), HIV/HCV coinfected patients treated with LDV/SOF at 3 hospitals in Newark, NJ between January 2014 and July 2016. Data collected included demographics, HCV treatment history, treatment duration, and response.One hundred seventeen HIV/HCV coinfected Black patients started treatment with LDV/SOF but 5 had no follow-up data and 5 prematurely discontinued treatment (1 due to side effects). We included 107 HIV/HCV coinfected patients who completed LDV/SOF at all 3 sites. The study population was 65% male, median age 58 years, 26% had cirrhosis, and 78% had GT1a. Thirty-one percent were treatment experienced but none with prior NS5a treatment. At baseline, median CD4 count was 680 cells/mm, HIV viral load (VL) was <40 copies/mL in 94% and median HCV VL was 2,257,403 IU/mL. Twenty-nine percent of patients changed antiretroviral treatment before LDV/SOF treatment due to drug interactions. Six, 89, and 12 patients completed 8, 12, and 24 weeks of LDV/SOF, respectively. Overall sustained virologic response rate was 93% with 7 relapses.In this real-world cohort of Black, GT1, HIV/HCV coinfected patients, LDV/SOF had high sustained virologic response 12 weeks post completion of treatment rate of 93%. This data supports the overall high efficacy of LDV/SOF in a historically difficult-to-treat patient population.

Cost-effectiveness of Using Kidneys From HCV-Viremic Donors for Transplantation Into HCV-Uninfected Recipients.

RATIONALE & OBJECTIVE: Less than 4% of patients with kidney failure receive kidney transplants. Although discard rates of hepatitis C virus (HCV)-viremic kidneys are declining, ~39% of HCV-viremic kidneys donated between 2018 and 2019 were discarded. Highly effective antiviral agents are now available to treat chronic HCV infection. Thus, our objective was to examine the cost-effectiveness of transplanting kidneys from HCV-viremic donors into HCV-uninfected recipients. STUDY DESIGN: Markov state transition decision model. Data sources include Medline search results, bibliographies from relevant English language articles, Scientific Registry of Transplant Recipients, and the US Renal Data System. SETTING & POPULATION: US patients receiving maintenance hemodialysis who are on kidney transplant waiting lists. INTERVENTION(S): Transplantation with an HCV-unexposed kidney versus transplantation with an HCV-viremic kidney and HCV treatment. OUTCOMES: Effectiveness measured in quality-adjusted life-years and costs measured in 2018 US dollars. MODEL, PERSPECTIVE, AND TIMEFRAME: We used a health care system perspective with a lifelong time horizon. RESULTS: In the base-case analysis, transplantation with an HCV-viremic kidney was more effective and less costly than transplantation with an HCV-unexposed kidney because of the longer waiting times for HCV-unexposed kidneys, the substantial excess mortality risk while receiving dialysis, and the high efficacy of direct-acting antiviral agents for HCV infection. Transplantation with an HCV-viremic kidney was also preferred in sensitivity analyses of multiple model parameters. The strategy remained cost-effective unless waiting list time for an HCV-viremic kidney exceeded 3.1 years compared with the base-case value of 1.56 year. LIMITATIONS: Estimates of waiting times for patients willing to accept an HCV-viremic kidney were based on data for patients who received HCV-viremic kidney transplants. CONCLUSIONS: Transplanting kidneys from HCV-viremic donors into HCV-uninfected recipients increased quality-adjusted life expectancy and reduced costs compared with a strategy of transplanting kidneys from HCV-unexposed donors.

Sofosbuvir-based regimens in the treatment of patients with chronic hepatitis C virus infection: Real-world efficacy in Thailand.

AIMS: To analyze the efficacy and safety of sofosbuvir (SOF)-based regimens in Thai patients with chronic hepatitis C virus infection who had pre-existing significant liver fibrosis. PATIENTS AND METHODS: This was a retrospective cohort study, conducted between 1 June 2018 and 31 May 2019 at Rajavithi Hospital, Bangkok, Thailand. All patients completed 12 weeks of SOF-based regimens and had follow-up for at least 12 weeks after therapy discontinuation. The primary outcome was sustained virological response (SVR) 12 weeks after the end of therapy. RESULT: A total of 185 patients were included, with 52, 63 and 70 taking SOF+Ledipasvir (SOF+LDV), SOF+LDV+ribavirin (RBV) and SOF+Pegylated interferon (Peg-IFN)+RBV (SOF+Peg-IFN+RBV) respectively. Genotype (GT) 1 was predominant at 40.0%, followed by GT3 at 37.8%, and GT6 at 22.2%. Overall 95.1% of patients in this study achieved SVR (n = 176/185), and the only factor associated with SVR was HCV genotype (p = 0.001). GT6 patients had lower SVR rates compared to GT1 and GT3 patients (82.9%, 98.6%, and 98.6% respectively) while there was no association between SVR and other factors (p >0.05) such as gender, age, BMI, underlying cirrhosis, baseline HCV viral load, or prior treatment history. No serious adverse events were reported in the present study. CONCLUSION: Sofosbuvir-based regimens in the treatment of patients with chronic HCV infection were highly efficacious with excellent safety and tolerability profiles in a real-world setting; however, further research is required to establish whether or not such a regimen is an adequate treatment for all genotype 6 patients.

Safety and Efficacy of 8 Weeks Ledipasvir/Sofosbuvir for Chronic Hepatitis C Genotype 4 in Children Aged 4-10 Years.

OBJECTIVE: To evaluate the safety and efficacy of shortened 8-week regimen of ledipasvir/sofosbuvir (LED/SOF) combination therapy in treatment-naïve children without cirrhosis aged 4-10 years of age with chronic hepatitis C virus (HCV) infection. STUDY DESIGN: This observational single arm prospective study included 30 treatment-naïve children (20 males) with proved chronic HCV fulfilling inclusion criteria. Their body weights ranged from 17 to 26 kg. Four patients were excluded from the study. All the included children received a single oral dose of LED/SOF 45/200 mg for 8 weeks. Body weight, HCV-RNA, complete blood count, and liver function tests were monitored at 0, 2, 4, and 8 weeks and sustained virologic response was evaluated after 12 weeks after treatment (SVR12). The emergence of any side effects was also monitored. RESULTS: The most common risk factor (53.3%) was an parent or sibling with HCV infection. Twenty-nine patients (96.7%) were negative for HCV-RNA by week 2 of treatment and 1 patient became negative by week 4. The end of treatment response and SVR12 were 100%. Transaminases levels declined and returned to normal levels by week 2. Major side effects were fatigue in 90% (27/30) and headache in 76.7% (23/30). Side effects were minimal, tolerable, and did not interfere with daily activity or necessitate treatment discontinuation. CONCLUSIONS: A shortened 8-week regimen of LED/SOF (45/200 mg) is safe and effective with 100% SVR12 in treatment-naïve children with cirrhosis aged 4-10 years with chronic HCV infection genotype 4.

Detecting Protein-Ligand Interaction from Integrated Transient Induced Molecular Electronic Signal (i-TIMES).

Quantitative information about protein-ligand interactions is central to drug discovery. To obtain the quintessential reaction dissociation constant, ideally measurements of reactions should be performed without perturbations by molecular labeling or immobilization. The technique of transient induced molecular electrical signal (TIMES) has provided a promising technique to meet such requirements, and its performance in a microfluidic environment further offers the potential for high throughput and reduced consumption of reagents. In this work, we further the development by using integrated TIMES signal (i-TIMES) to greatly enhance the accuracy and reproducibility of the measurement. While the transient response may be of interest, the integrated signal directly measures the total amount of surface charge density resulted from molecules near the surface of electrode. The signals enable quantitative characterization of protein-ligand interactions. We have demonstrated the feasibility of i-TIMES technique using different biomolecules including lysozyme, N,N',N″-triacetylchitotriose (TriNAG), aptamer, p-aminobenzamidine (pABA), bovine pancreatic ribonuclease A (RNaseA), and uridine-3'-phosphate (3'UMP). The results show i-TIMES is a simple and accurate technique that can bring tremendous value to drug discovery and research of intermolecular interactions.

Real-world efficacy of direct acting antiviral therapies in patients with HIV/HCV.

The advent of direct-acting antiviral (DAA) therapies has dramatically transformed HCV treatment, with most recent trials demonstrating high efficacy rates (>90%) across all genotypes and special populations, including patients with HIV/HCV coinfection. The efficacy rates of HCV treatment are nearly identical between patients with HCV monofection and patients with HIV/HCV coinfection; however, there are limited studies to compare real-world efficacy with efficacy observed in clinical trials. Using a database from HIV clinics across the United States (US), we identified 432 patients with HIV/HCV coinfection who completed DAA therapy from January 1, 2014 to March 31, 2017 and were assessed for efficacy. Efficacy was evaluated as sustained virologic response (SVR) 12 weeks after DAA completion; furthermore, factors associated with achieving SVR12 were identified. In this analysis, we found DAA therapies to be effective, with 94% of the patients achieving SVR12 and 6% experiencing virologic failure. Baseline variables, including older age, HCV viral load <800K IU/ML, FIB-4 score <1.45, absence of depression, diabetes, substance abuse, and use of DAA regimens without ribavirin were significant predictors of achieving SVR12. Patients with fewer comorbidities, better liver health, and lower HCV viral loads at baseline were more likely to achieve treatment success. Our results were consistent with other real-world studies, supporting the use of HCV therapy in HIV/HCV coinfected patients.

Generic Ledipasvir-Sofosbuvir Treatment for Adolescents With Chronic Hepatitis C Virus Infection.

We assessed the safety and efficacy of a generic form of ledipasvir-sofosbuvir for the treatment of hepatitis C virus infection in Egyptian adolescents and compared the results with those of treatment with the brand-named form. The generic form resulted in a high response rate, significant improvement in liver function, and mild adverse effects. These results are comparable with those of the brand form at a reduced price.

Ledipasvir-Sofosbuvir for 12 Weeks in Children 3 to <6 Years Old With Chronic Hepatitis C.

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.

Resistance-associated substitution and ledipasvir/sofosbuvir therapy in Mongolian chronic hepatitis C patients.

BACKGROUND: Mongolia has the highest prevalence of hepatitis C virus (HCV) infection worldwide. Ledipasvir/sofosbuvir (LDV/SOF) was introduced to Mongolia since 2016 for HCV eradication. It has been reported that HCV resistance-associated substitutions (RASs) would affect the effectiveness of LDV/SOF in western chronic hepatitis C (CHC) patients. We thus investigated the effectiveness of LDV/SOF and the impact of RAS on the treatment outcome in Mongolian CHC patients. METHODS: Patients with genotype (GT) 1b HCV infection were prospectively enrolled in Mongolia and treated with LDV/SOF for 12 weeks. The proportion of pre-treatment NS5A Y93H RAS in viral quasispecies was measured with next-generation sequencing. The endpoint of LDV/SOF effectiveness was sustained virological response at post-treatment week 12 (SVR12). RESULTS: A total of 94 CHC patients were evaluated. The baseline Y93H proportion was <1% in 74 patients, 1-15% in 7, 15-50% in 2, and ≥50% in 11. All patients completed 12-week LDV/SOF treatment and the SVR rate was 90.4%. The rate of failure to achieve SVR12 for patients with Y93H < 1%, 1-15%, and ≥15% were 0%, 14.3%, and 61.5%, respectively (p for trend = 0.001). In univariable analysis, older age, baseline alanine transaminase level <40 U/mL, and a higher proportion of Y93H were associated with treatment failure. In multivariable analysis, only a higher proportion of Y93H was associated with treatment failure (p = 0.022). CONCLUSION: LDV/SOF therapy achieves a high SVR rate in Mongolian CHC GT1b patients without baseline Y93H RAS. A higher proportion of Y93H may severely undermine the effectiveness of LDV/SOF.

Trends in Renal Function Among Heart Transplant Recipients of Donor-Derived Hepatitis C Virus.

Donor-derived hepatitis C (dd-HCV) infection may increase the risk of renal impairment (RI) among heart transplantation (HT) recipients. Sofosbuvir, an integral component of HCV direct-acting antivirals (DAAs) has also been linked to RI. To date, no study has examined the trends in renal function for HT recipients of dd-HCV infection and assessed safety and efficacy of Sofosbuvir-based DAAs. Between September 2016 and June 2018, 46 HCV-naive patients and one patient with a history of HCV treated pretransplant, underwent HT from HCV-positive donors (follow-up available through October 10, 2018). Patients were treated with Ledipasvir-Sofosbuvir (genotype 1) or Sofosbuvir-Velpatasvir (genotype 3) for 12 or 24 weeks; no dose adjustments were made for renal function. Data on renal function were available for 23 patients who achieved a sustained virologic response at 12 weeks after the treatment (SVR12; cohort A) and 18 patients who completed 1 year of follow-up (cohort B). Treatment of dd-HCV infection was initiated at a median of 6 weeks post-HT. In both cohorts, a nonsignificant reduction in median estimated glomerular filtration rate (eGFR; ml/min/1.73 m) was noted (cohort A: pretransplant eGFR: 62 [interquartile range {IQR}: 1-84] to SVR12 eGFR: 49 [IQR: 37-82]; p = 0.43; cohort B: pretransplant eGFR: 65 [IQR: 54-84] to 1 year post-HT eGFR: 56 [IQR: 39-75]; p = 0.29). Pretreatment renal function had no significant impact on changes in renal function during treatment. All patients tolerated DAAs well with 100% completion rate to the assigned therapy and duration and 100% success at achieving SVR12. In this first and largest reported case series to date of HT recipients with dd-HCV infection, we observed that neither the dd-HCV infection nor its treatment with Sofosbuvir-based DAAs increased the risk of RI. Sofosbuvir-based DAAs appear safe, tolerable, and effective for HCV treatment even in presence of severe RI.

Sustainable synthesis of uridine-5'-monophosphate analogues by immobilized uracil phosphoribosyltransferase from Thermus thermophilus.

Nowadays enzymatic synthesis of nucleic acid derivatives is gaining momentum over traditional chemical synthetic processes. Biotransformations catalyzed by whole cells or enzymes offer an ecofriendly and efficient alternative to the traditional multistep chemical methods, avoiding the use of chemical reagents and organic solvents that are expensive and environmentally harmful. Herein we report for the first time the covalent immobilization a uracil phosphoribosyltransferase (UPRT). In this sense, UPRT from Thermus thermophilus HB8 was immobilized onto glutaraldehyde-activated MagReSyn®Amine magnetic iron oxide porous microparticles (MTtUPRT). According to the catalyst load experiments, MTtUPRT3 was selected as optimal biocatalyst for further studies. MTtUPRT3 was active and stable in a broad range of temperature (70-100 °C) and in the pH interval 6-8, displaying maximum activity at 100 °C and pH 7 (activity 968 IU/gsupport, retained activity 100%). In addition, MTtUPRT3 could be reused up to 8 times in the synthesis of uridine-5'-monophosphate (UMP). Finally, MTtUPRT3 was successfully applied in the sustainable synthesis of different 5-modified uridine-5'-monophosphates at short times. Taking into account these results, MTtUPRT3 would emerge as a valuable biocatalyst for the synthesis of nucleoside monophosphates through an efficient and environmentally friendly methodology.