Sofosbuvir, a drug developed
by Gilead Sciences, has been proven to be very effective in treating various
subtypes of chronic Hepatitis C Virus Infection; the drug is currently in
its phase III clinical trials.
Researchers conducted two open label trials to compare the efficacy of the new drug with the current treatment regimen of ribavirin and peginterferon alfa-2a. Patients enrolled in the study were not treated previously for HCV infection and 20% of them had liver cirrhosis.
The first study involved 327 patients infected with HCV genotype 1, 4, 5, or 6. All patients in this trial received sofosbuvir, ribavirin, and peginterferon alfa-2a for 12 weeks.
Serum HCV RNA levels were measured and IL28B genotyping was done to evaluate the response to HCV therapy. By the end of fourth week, 99% of patients who received sofosbuvir in both the trials recorded a drastic reduction in serum HCV RNA levels.
In the first single-group study, 89% of patients with HCV genotype 1 and 96% of patients with HCV genotype 4 had sustained virologic response i.e. undetectable levels of serum HCV RNA levels 12 weeks after the treatment.
In the randomized study, 67% of patients from each group had sustained virologic response. However, the response rate among patients with genotype 2 infection was higher than among those with genotype 3 infection and taking sofosbuvir-ribavirin combination of drugs.
Adverse effects like anemia and other Hematologic disorders were more common among patients on peginterferon-ribavirin regimen than those on sofosbuvir-ribavirin treatment. Researchers could not detect any viral resistant mutations in the blood samples of patients who had a relapse. This necessitates further research to identify the cause of relapse.
Authors thus conclude that the efficacy of Sofosbuvir is impressive and the drug regimen needs further analysis to improve the response rates in patients with genotype 3 infection.
Reference : Sofosbuvir for Previously Untreated Chronic Hepatitis C Infection; Eric Lawitz et al; NEJM April 2013.