Gilead Sciences, Inc. has announced results from an open-label clinical trial (Study GS-US-334-0109) evaluating once-daily Sovaldi® (sofosbuvir) 400 mg tablets for the retreatment of chronic hepatitis C virus (HCV) infection among patients who failed prior therapy. These data will be presented in two oral sessions at the 49th Annual Meeting of the European Association for the Study of the Liver (The International Liver Congress 2014) in London.
In Study GS-US-334-0109 (Oral #55), patients with genotype 1 HCV infection (n=80) received 12 weeks of treatment with once-daily Sovaldi plus weight-based ribavirin (RBV) twice-daily (1,000 or 1,200 mg/day) and pegylated interferon (peg-IFN; 180 μg/week). Patients in the study had failed prior regimens containing peg-IFN, RBV and an investigational NS3 protease inhibitor, with or without investigational direct-acting antivirals (DAAs) (NS5A and/or non-nucleoside NS5B inhibitors). Forty-five percent of patients (n=36) had received more than one course of prior therapy, and 90 percent (n=72) had at least one viral mutation associated with HCV NS3, NS5A or NS5B drug resistance.
Among the 50 patients for whom sustained virologic response data was available 12 weeks after the end of treatment (SVR12), 74 percent (n=37/50) achieved SVR12. Additionally, 80 percent (n=28/35) of patients with baseline resistance against two or more DAAs achieved SVR12.
"This study demonstrates that Sovaldi-based regimens can achieve high cure rates even among hepatitis C patients who previously failed therapy with baseline resistance to at least two DAAs," said Stanislas Pol, MD, PhD, Professor of Hepatology and Gastroenterology, Paris Descartes University, Paris, France, and a principal investigator. "Importantly, Sovaldi has now demonstrated efficacy among genotype 1 HCV infected patients who failed prior treatment with three or four drug regimens and have developed viral resistance to some of the components of those regimens."
In a separate presentation (Oral #8), retreatment with Sovaldi in genotype 2 (n=11) or genotype 3 (n=96) HCV infected patients who previously failed treatment with 12 or 16 weeks of Sovaldi plus RBV in the Phase 3 studies FISSION, FUSION and POSITRON was evaluated. Thirty-six percent of these patients (39/107) had cirrhosis. Patients were retreated either with a 12-week regimen of Sovaldi, RBV and peg-IFN, or a 24-week, interferon-free regimen of Sovaldi plus RBV. The choice of regimen was determined by study investigators.
Among patients with available SVR12 data, 63 percent (n=25/40) of those who received the 24-week all-oral regimen and 92 percent (n=24/26) of those who received the 12-week regimen of Sovaldi, RBV, and peg-IFN achieved SVR12.
"For patients with genotypes 2 and 3 who have failed a prior suboptimal sofosbuvir regimen, Sovaldi may offer an effective retreatment option," said Rafael Esteban, MD, Head of the Internal Medicine and Liver Unit, Hospital Universitari Vall d'Hebron and Professor of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain and a principal investigator for the study.
Sovaldi was well tolerated in Study GS-US-334-0109. The most common adverse events were consistent with the safety profiles of peg-IFN and/or RBV. Additional information about the study can be found at www.clinicaltrials.gov.
Sovaldi is an oral nucleotide analog inhibitor of the HCV NS5B polymerase enzyme, which plays an essential role in HCV replication. Sovaldi is a direct-acting agent, meaning that it interferes directly with the HCV life cycle by suppressing viral replication.
Sovaldi was approved in the United States on December 8, 2013 and in the European Union on January 17. In the United States, Sovaldi is approved for the treatment of chronic hepatitis C infection as a component of a combination antiviral treatment regimen. Efficacy has been established in subjects with HCV genotype 1, 2, 3 or 4 infection, including those with hepatocellular carcinoma meeting Milan criteria (awaiting liver transplantation) and those with HCV/HIV-1 co-infection.. Treatment response varies based on baseline host and viral factors. Monotherapy is not recommended for treatment of chronic hepatitis C. Study GS-US-334-0109 evaluated investigational uses of Sovaldi, for which safety and efficacy have not yet been established.
Important Safety Information
Sovaldi combination treatment with ribavirin or with peginterferon alfa plus ribavirin is contraindicated in women who are pregnant or may become pregnant and men whose female partners are pregnant because of the risk for birth defects and fetal death associated with ribavirin. Other contraindications to peginterferon alfa and ribavirin also apply to Sovaldi combination treatment. Refer to the prescribing information of peginterferon alfa and ribavirin for a list of their contraindications.
Warnings and Precautions
Pregnancy: Use with Ribavirin or Peginterferon Alfa/Ribavirin: Ribavirin therapy should not be started unless a report of a negative pregnancy test has been obtained immediately prior to initiation of therapy. Female patients of childbearing potential and their male partners must use two forms of non-hormonal contraception during treatment and for at least 6 months after treatment has concluded. Routine monthly pregnancy tests must be performed during this time. Refer to the prescribing information for ribavirin.
Use with Potent P-gp Inducers: Rifampin and St. John's wort should not be used with Sovaldi as they may significantly decrease sofosbuvir plasma concentration, reducing its therapeutic effect.
Most common (≥20 percent, all grades) adverse reactions for:
- Sovaldi + peginterferon alfa + ribavirin combination therapy were fatigue, headache, nausea, insomnia, and anemia
- Sovaldi + ribavirin combination therapy were fatigue, and headache
In addition to rifampin and St. John's wort, coadministration of Sovaldi is not recommended with carbamazepine, oxcarbazepine, phenobarbital, phenytoin, rifabutin and rifapentine. Such coadministration is expected to decrease the concentration of sofosbuvir, reducing its therapeutic effect.