Study: Twice Weekly Dose Better for Hep C
But Hepatitis Experts Remain Skeptical
Hepatitis C treatment expert Bruce Bacon, MD, says the study has little clinical relevance precisely because the researchers did not look at whether the different dosing frequencies effectively clear the virus from blood and led to a sustained undetectable level of virus, which means the patient has cleared the virus and no longer has the infection. Bacon is director of the division of hepatology at Saint Louis University School of Medicine.
"These authors did not look at the only endpoint that matters," he tells WebMD. "If they were telling us that they had achieved a better sustained response with these patients, then that would be huge. But the patients were only followed for four weeks."
Most hepatitis C patients in the U.S. are treated for 48 weeks with a combination of pegylated interferon and the drug ribavirin. Seven years ago, only about 10% of patients achieved sustained responses. More than half of patients are cured today with the combination regimen.
Bacon says it is not clear if the response that was seen in the study within the early weeks of treatment is predictive of eventual viral clearance.
"Early response is of clinical interest, but it is of practical use only when there is an absence of response," he says. "That is why we do not continue treating patients who have not responded after 12 weeks of therapy."
Infectious disease specialist Margaret Koziel, MD, agrees that even if twice-weekly dosing does result in a better initial response to treatment, that is not necessarily predictive of a higher cure rate. She also expressed concerns about the greater potential for severe side effects with twice-weekly dosing. Koziel is an assistant professor of medicine at Harvard Medical School and a staff physician at Beth Israel Deaconess Medical Center.
Common side effects of interferon treatment include flu-like symptoms, fatigue, depression, and immune system suppression. The two treatment groups in this study had similar rates of these side effects, but Koziel says that does not mean they would continue to do so throughout treatment.
"Even if the dosage were the same, twice-weekly dosing could certainly have an impact on toxicity," she says. "These patients were not followed long enough to know."