Pharmacokinetic Profile of a Generic Formulation of Sofosbuvir and Its Metabolite GS-331007 in Healthy Chinese Subjects

Single-Ascending-Dose, Food-Effect, and Multiple-Dose Study of the Safety, Tolerability, and Pharmacokinetics of the Pangenotypic Anti-Hepatitis C Virus Drug Holybuvir in Healthy Chinese Subjects

Holybuvir is a novel pangenotypic hepatitis C virus NS5B inhibitor. This first in-human study aimed to evaluate the pharmacokinetics (PK), safety, and tolerability of holybuvir and its metabolites and the effect of food on the PK of holybuvir and its metabolites in healthy Chinese subjects. A total of 96 subjects were enrolled in this study which included (i) a single-ascending-dose (SAD) study (100 to 1,200 mg), (ii) a food-effect (FE) study (600 mg), and (iii) a multiple-dose (MD) study (400 and 600 mg once daily for 14 days). The results showed that single oral administration of holybuvir at doses up to 1,200 mg was well tolerated. Holybuvir was rapidly absorbed and metabolized in the human body, which was consistent with the characteristics of holybuvir as a prodrug. PK analysis showed that Cmax and area under the curve (AUC) increased with dose in no dose-proportional manner after a single-dose administration (100 to 1,200 mg). Although high-fat meals did change the PK of holybuvir and its metabolites, clinical significance of changes in PK parameters induced by eating a high-fat diet would be further confirmed. Following multiple-dose administration, accumulation of metabolites SH229M4 and SH229M5-sul was observed. The favorable PK and safety results support the further development of holybuvir for patients with HCV. (This study was registered at Chinadrugtrials.org under identifier CTR20170859.).

Development and validation of LC-MS/MS methods for the simultaneous quantification of sofosbuvir and its major metabolite (GS-331007) in blood plasma and cerebrospinal and seminal fluid: Application to a pilot clinical trial with a focus on Zika

Zika still poses a threat to global health owing to its association with serious neurological conditions and the absence of a vaccine and treatment. Sofosbuvir, an anti-hepatitis C drug, has shown anti-Zika effects in animal and cell models. Thus, this study aimed to develop and validate novel LC-MS/MS methods for the quantification of sofosbuvir and its major metabolite (GS-331007) in human plasma and cerebrospinal (CSF) and seminal fluid (SF), and apply the methods to a pilot clinical trial. The samples were prepared by liquid-liquid extraction and separated using isocratic mode on Gemini C₁₈ columns. Analytical detection was performed using a triple quadrupole mass spectrometer equipped with an electrospray ionization source. The validated ranges for sofosbuvir were 0.5-2,000 ng/mL (plasma) and 0.5-100 ng/mL (CSF and SF), while for the metabolite they were 2.0-2,000 ng/mL (plasma), 5.0-200 ng/mL (CSF) and 10-1,500 ng/mL (SF). The intra-day and inter-day accuracies (90.8-113.8%) and precisions (1.4-14.8%) were within the acceptance range. The developed methods fulfilled all validation parameters concerning selectivity, matrix effect, carryover, linearity, dilution integrity, precision, accuracy and stability, confirming the suitability of the method for the analysis of clinical samples.

A pharmacometric approach to evaluate drugs for potential repurposing as COVID-19 therapeutics

INTRODUCTION

Developing and evaluating novel compounds for treatment or prophylaxis of emerging infectious diseases is costly and time-consuming. Repurposing of already available marketed compounds is an appealing option as they already have an established safety profile. This approach could substantially reduce cost and time required to make effective treatments available to fight the COVID-19 pandemic. However, this approach is challenging since many drug candidates show efficacy in in vitro experiments, but fail to deliver effect when evaluated in clinical trials. Better approaches to evaluate in vitro data are needed, in order to prioritize drugs for repurposing.

AREAS COVERED

This article evaluates potential drugs that might be of interest for repurposing in the treatment of patients with COVID-19 disease. A pharmacometric simulation-based approach was developed to evaluate in vitro activity data in combination with expected clinical drug exposure, in order to evaluate the likelihood of achieving effective concentrations in patients.

EXPERT OPINION

The presented pharmacometric approach bridges in vitro activity data to clinically expected drug exposures, and could therefore be a useful compliment to other methods in order to prioritize repurposed drugs for evaluation in prospective randomized controlled clinical trials.

Sofosbuvir plus Ribavirin is effective for HCV elimination in people living with HIV from rural area of China

People living with HIV (PLWH) bear higher prevalence of HCV coinfection. An accessible directly acting antivirals regimen with less drug-drug interaction with antiretroviral therapy (ART) is urgently needed in source limited regions. We aimed to assess the efficacy and safety of SOF + RBV for 24 weeks regimen in HIV-HCV coinfected patients in Liangshan Prefecture, China. PLWH under ART from China's national free antiretroviral treatment project (CNFATP) and diagnosed with treatment-naïve HCV infection were enrolled. SOF + RBV was administrated for 24 weeks and patients were followed for ≥ 12 weeks. The efficacy and safety were analyzed and related factors were explored. 58 patients completed 24 weeks of SOF + RBV and had all tests done. Genotype prevalence in this population was G3 44.8% (n = 26), G6 31.0% (n = 18) and G1 17.2% (n = 10) respectively. 52/58 (89.7%) patients achieved SVR12 while 10.3% experienced therapeutic failure. However, SVR12 was neither significantly different between groups of different gender, age, transmission routines, CD4+ cell count, HIV infection duration, ART duration and HBsAg prevalence nor influenced by HCV viral load, genotypes and hepatic stiffness. The regimen was well-tolerated without any serious AEs or AEs leading to treatment adjustment or discontinuation reported. PLWH in Liangshan showed a high prevalence of HCV coinfection with GT3 and GT6 as the most frequent genotypes. SOF + RBV for 24 weeks could achieve good SVR12 in this population and was well-tolerated. It has great potential to be generalized in coinfected population in source-limited regions.

Molecular docking and statistical optimization of taurocholate-stabilized galactose anchored bilosomes for the enhancement of sofosbuvir absorption and hepatic relative targeting efficiency

The work aimed to improve both absorption and hepatic availability of sofosbuvir. Bilosomes and galactose-anchored bilosomes were investigated as potential nanocarriers for this purpose. Sofosbuvir is a class III drug with high solubility and low permeability. Thus, the drug entrapment into lipid-based galactose-anchored carriers would enhance drug permeability and improve its liver availability. The galactosylated taurocholate was designed and synthesized based on molecular docking studies, where both galactose and taurocholate molecules were connected in a way to avoid affecting crucial interactions and avoid steric clashes with their cellular uptake receptors. The suggested nano-carriers were prepared using a thin-film hydration technique with sodium taurocholate and span 60 as stabilizers. The prepared formulae were statistically optimized using a central composite design. The optimized plain and galactosylated formulae, composed of SAA to drug ratio of 1:1 w/w and sodium taurocholate to span ratio of 10:1 w/w, have a vesicular size, zeta potential and entrapment efficiency in the range of 140-150 nm, -50 mV and 85%, respectively. The optimized formulae were lyophilized to increase their physical stability and facilitate accurate drug dosing. In vivo results showed that Sofosbuvir availability in the liver was significantly increased after oral administration of the plain and the galactosylated bilosomal formulae when compared to the oral drug solution with relative targeting efficiencies (RTIs) of 1.51 and 3.66, respectively. These findings confirmed the hypothesis of considering the galactosylated bilosomes a promising nanocarrier to efficiently target sofosbuvir to the liver.