Efficacy of Sofosbuvir Plus Ribavirin in Veterans With Hepatitis C Virus Genotype 2 Infection, Compensated Cirrhosis, and Multiple Comorbidities.

BACKGROUND & AIMS: We conducted a phase 4, open-label study with limited exclusion criteria to evaluate the safety and efficacy of sofosbuvir and ribavirin in veterans with hepatitis C virus genotype 2 infection, and compensated cirrhosis. This population is often excluded from clinical studies. METHODS: We performed a prospective study of treatment-naive (n = 47) and treatment-experienced (n = 19) patients with chronic hepatitis C virus genotype 2 infection and compensated cirrhosis at 15 Department of Veterans Affairs sites. All subjects were given sofosbuvir (400 mg, once daily) plus ribavirin (1000-1200 mg/day) in divided doses for 12 weeks. Patients with major psychiatric diseases or alcohol or substance use disorders were not excluded. The primary endpoint was sustained virologic response 12 weeks after therapy. RESULTS: Fifty-two patients achieved a sustained virologic response 12 weeks after therapy (79%; 95% confidence interval, 67%-88%); 16 of these patients were treatment experienced (84%; 95% confidence interval, 60%-97%) and 36 were treatment naive (77%; 95% confidence interval, 62%-88%). All patients had at least 1 comorbidity. Thirty-five percent had depression, 24% had posttraumatic stress disorder, and 30% had anxiety disorder. In addition, 29% had current substance use. Of the 7 patients (11%) who discontinued the study treatment prematurely, 3 did so because of adverse events. The most common adverse events were fatigue, anemia, nausea, and headache. Serious adverse events occurred in 8 patients. Only 2 of the serious adverse events (anemia and nausea) were considered to be related to study treatment. CONCLUSIONS: In a phase 4 study, 12 weeks treatment with sofosbuvir and ribavirin led to a sustained virologic response 12 weeks after therapy in almost 80% of veterans with hepatitis C virus genotype 2 infection, compensated cirrhosis, and multiple comorbidities, regardless of their treatment history. ClinicalTrials.gov, Number: NCT02128542.

Cobicistat boosts the intestinal absorption of transport substrates, including HIV protease inhibitors and GS-7340, in vitro.

The experimental pharmacoenhancer cobicistat (COBI), a potent mechanism-based inhibitor of cytochrome P450 3A enzymes, was found to inhibit the intestinal efflux transporters P-glycoprotein and breast cancer resistance protein. Consistent with its transporter inhibition, COBI significantly increased the absorptive flux of potential candidates for clinical coadministration, including the HIV protease inhibitors atazanavir and darunavir and the lymphoid cell- and tissue-targeted prodrug of the nucleotide analog tenofovir, GS-7340, through monolayers of Caco-2 cells in vitro.

Molecular assessment of the potential for renal drug interactions between tenofovir and HIV protease inhibitors.

BACKGROUND: Active renal secretion of tenofovir (TFV) across proximal tubules occurs via uptake by human organic anion transporters 1 and 3 (hOAT1 and hOAT3) coupled with efflux by multidrug resistance protein 4 (MRP4). Co-administration of some HIV protease inhibitors (PIs) with tenofovir disoproxil fumarate (TDF), an oral prodrug of TFV, has been shown to increase systemic levels of TFV, leading to a hypothesis that PIs may affect tubular secretion of TFV and potentially alter the renal safety of TDF. METHODS: The effect of PIs on the transport of TFV by hOAT1, hOAT3 and MRP4 was assessed using in vitro cell-based transport models. RESULTS: At concentrations equal to their therapeutic peak plasma levels (Cmax) all PIs showed <20% inhibition of TFV transport by hOAT1. hOAT3 was more sensitive to Pls with ritonavir (RTV) and lopinavir being the most potent inhibitors of TFV transport (62% and 37% inhibition, respectively, at their Cmax). In the absence of human serum, RTV at concentrations exceeding its therapeutic Cmax also exhibited a minor effect on the cellular efflux of TFV by MRP4 (<30% inhibition at 20 microM). However, no effects of PIs on hOAT1, hOAT3 or MRP4 were detected in the presence of human serum with the exception of RTV that inhibited hOAT3 by approximately 35% at its Cmax. In addition, PIs did not affect the cytotoxicity of TFV or TDF in MRP4- or MRP2-overexpressing cells. CONCLUSION: These data indicate a low potential of PIs to interfere with the active tubular secretion of TFV and to alter the clinical renal safety profile of TDF.