Nucleotide polymerase inhibitor sofosbuvir plus ribavirin for hepatitis C.

BACKGROUND: The standard treatment for hepatitis C virus (HCV) infection is interferon, which is administered subcutaneously and can have troublesome side effects. We evaluated sofosbuvir, an oral nucleotide inhibitor of HCV polymerase, in interferon-sparing and interferon-free regimens for the treatment of HCV infection. METHODS: We provided open-label treatment to eight groups of patients. A total of 40 previously untreated patients with HCV genotype 2 or 3 infection were randomly assigned to four groups; all four groups received sofosbuvir (at a dose of 400 mg once daily) plus ribavirin for 12 weeks. Three of these groups also received peginterferon alfa-2a for 4, 8, or 12 weeks. Two additional groups of previously untreated patients with HCV genotype 2 or 3 infection received sofosbuvir monotherapy for 12 weeks or sofosbuvir plus peginterferon alfa-2a and ribavirin for 8 weeks. Two groups of patients with HCV genotype 1 infection received sofosbuvir and ribavirin for 12 weeks: 10 patients with no response to prior treatment and 25 with no previous treatment. We report the rate of sustained virologic response 24 weeks after therapy. RESULTS: Of the 40 patients who underwent randomization, all 10 (100%) who received sofosbuvir plus ribavirin without interferon and all 30 (100%) who received sofosbuvir plus ribavirin for 12 weeks and interferon for 4, 8, or 12 weeks had a sustained virologic response at 24 weeks. For the other patients with HCV genotype 2 or 3 infection, all 10 (100%) who received sofosbuvir plus peginterferon alfa-2a and ribavirin for 8 weeks had a sustained virologic response at 24 weeks, as did 6 of 10 (60%) who received sofosbuvir monotherapy. Among patients with HCV genotype 1 infection, 21 of 25 previously untreated patients (84%) and 1 of 10 with no response to previous therapy (10%) had a sustained virologic response at 24 weeks. The most common adverse events were headache, fatigue, insomnia, nausea, rash, and anemia. CONCLUSIONS: Sofosbuvir plus ribavirin for 12 weeks may be effective in previously untreated patients with HCV genotype 1, 2, or 3 infection. (Funded by Pharmasset and Gilead Sciences; ClinicalTrials.gov number, NCT01260350.).

Antiviral activity, safety, and pharmacokinetics of danoprevir/ritonavir plus PEG-IFN α-2a/RBV in hepatitis C patients.

BACKGROUND & AIMS: Danoprevir (RG7227; ITMN-191) is a potent inhibitor of the HCV NS3/4A serine protease. The aims of this double-blind, placebo-controlled, multiple-ascending dose phase Ib study were to evaluate safety, tolerability, antiviral activity, resistance, and pharmacokinetics of once- and twice-daily danoprevir in the presence of low-dose ritonavir (danoprevir/r) and in combination with peginterferon alfa-2a (40KD)/ribavirin in treatment-naive HCV genotype 1 patients. METHODS: Thirty eligible patients were enrolled into three cohorts and treated with danoprevir/r or placebo/r all in combination with peginterferon alfa-2a (40KD)/ribavirin for 15 days. Cohort 1 received danoprevir/r at 100/100mg twice daily; Cohort 2 200/100mg once daily; and Cohort 3 200/100mg twice daily. RESULTS: The median reductions in HCV RNA from baseline after 14 days of treatment (day 15) were -5.1, -4.8, and -4.6 log(10)IU/ml in Cohorts 1, 2, and 3, respectively, and -2.7 log(10) in placebo/r and peginterferon alfa-2a (40KD)/ribavirin recipients. Viral breakthrough was not observed in any patient. On day 15, HCV RNA was undetectable (<15IU/ml) in 6/9 (67%), 4/8 (50%), and 8/8 (100%) patients in Cohorts 1, 2, and 3, respectively. When co-administered with low dose ritonavir, danoprevir concentrations reached a steady state between 6 to 10 days of dosing. Danoprevir exposures increased more than dose proportionally between 100/100mg and 200/100mg. Danoprevir/r plus peginterferon alfa-2a (40KD)/ribavirin was well-tolerated with no safety-related discontinuations. CONCLUSIONS: Danoprevir/r plus peginterferon alfa-2a (40KD)/ribavirin provides profound and robust reductions in serum HCV RNA, at substantially lower systemic exposures compared to those observed with higher doses of danoprevir in the absence of ritonavir. These results support further studies of danoprevir/r.

Oral combination therapy with a nucleoside polymerase inhibitor (RG7128) and danoprevir for chronic hepatitis C genotype 1 infection (INFORM-1): a randomised, double-blind, placebo-controlled, dose-escalation trial.

BACKGROUND: Present interferon-based standard of care treatment for chronic hepatitis C virus (HCV) infection is limited by both efficacy and tolerability. We assessed the safety, tolerability, and antiviral activity of an all-oral combination treatment with two experimental anti-HCV drugs-RG7128, a nucleoside polymerase inhibitor; and danoprevir, an NS3/4A protease inhibitor-in patients with chronic HCV infection. METHODS: Patients from six centres in New Zealand and Australia who were chronically infected with HCV genotype 1 received up to 13 days oral combination treatment with RG7128 (500 mg or 1000 mg twice daily) and danoprevir (100 mg or 200 mg every 8 h or 600 mg or 900 mg twice daily) or placebo. Eligible patients were sequentially enrolled into one of seven treatment cohorts and were randomly assigned by interactive voice or web response system to either active treatment or placebo. Patients were separately randomly assigned within each cohort with a block size that reflected the number of patients in the cohort and the ratio of treatment to placebo. The random allocation schedule was computer generated. Dose escalation was started in HCV treatment-naive patients; standard of care treatment-experienced patients, including previous null responders, were enrolled in higher-dose danoprevir cohorts. Investigators, personnel at the study centre, and patients were masked to treatment allocation. However, the pharmacist who prepared the doses, personnel involved in pharmacokinetic sample analyses, statisticians who prepared data summaries, and the clinical pharmacologists who reviewed the data before deciding to initiate dosing in the next cohort were not masked to treatment allocation. The primary outcome was change in HCV RNA concentration from baseline to day 14 in patients who received 13 days of combination treatment. All patients who completed treatment with the study drugs were included in the analyses. This study is registered with ClinicalTrials.gov, NCT00801255. FINDINGS: 88 patients were randomly assigned to a study drug treatment regimen (n=74 over seven treatment groups; 73 received at least one dose of study drug) or to placebo (n=14, all of whom received at least one dose). The median change in HCV RNA concentration from baseline to day 14 ranged from -3·7 to -5·2 log(10) IU/mL in the cohorts that received 13 days of combination treatment. At the highest combination doses tested (1000 mg RG7128 and 900 mg danoprevir twice daily), the median change in HCV RNA concentration from baseline to day 14 was -5·1 log(10) IU/mL (IQR -5·6 to -4·7) in treatment-naive patients and -4·9 log(10) IU/mL in previous standard of care null responders (-5·2 to -4·5) compared with an increase of 0·1 log(10) IU/mL in the placebo group. The combination of RG7128 and danoprevir was well tolerated with no treatment-related serious or severe adverse events, no grade 3 or 4 changes in laboratory parameters, and no safety-related treatment discontinuations. INTERPRETATION: This oral combination of a nucleoside analogue polymerase inhibitor and protease inhibitor holds promise as an interferon-free treatment for chronic HCV. FUNDING: Roche Palo Alto.

Ritonavir-boosted danoprevir-based regimens in treatment-naive and prior null responders with HCV genotype 1 or 4 and compensated cirrhosis.

BACKGROUND AND AIM: Effective and safe antiviral treatment regimens are needed for patients with chronic hepatitis C (CHC) and cirrhosis. METHODS: An international open-label trial was conducted in CHC patients with genotype (G)1/4 infection, compensated cirrhosis, HCV RNA ≥ 50,000 IU/mL and body mass index 18-35 kg/m(2). Treatment-naive patients (Cohort 1) received a triple therapy regimen [danoprevir/r 100/100 mg twice daily (bid), ribavirin 1000/1200 mg/day and peginterferon alfa-2a 180 µg/week] for 24 weeks. Prior null responders (Cohort 2) received a quadruple therapy regimen (danoprevir/r 100/100 mg bid, mericitabine 1000 mg bid and peginterferon alfa-2a/ribavirin). The primary efficacy outcome was sustained virological response (HCV RNA < limit of quantification, target not detected) at end of the 24-week follow-up period (SVR24). RESULTS: In Cohort 1 (n = 23), 73.9 and 65.2 % of patients had a virological response at Weeks 4 and 24, respectively; 39.1 % achieved SVR24 (G1a = 1/13; G1b = 8/9; G4 = 0/1). In Cohort 2 (n = 20), 100 % achieved virological response at Weeks 4 and 24; 65 % achieved SVR24 (G1a = 4/8; G1b = 7/10; G4 = 2/2). Treatment failure was more common in G1a than G1b-infected patients and less common in patients receiving quadruple therapy. Treatment failure was associated with emergence of resistance to danoprevir, but not mericitabine. The safety profile was typical of that associated with peginterferon alfa-2a/ribavirin. No deaths/episodes of hepatic decompensation occurred. CONCLUSIONS: Treatment with danoprevir/r-based regimens for 24 weeks is safe and well tolerated in CHC patients with compensated cirrhosis. A quadruple therapy regimen (danoprevir/r, mericitabine, peginterferon alfa/ribavirin) produced high SVR24 rates in prior null responders, particularly among G1b patients.