NEW YORK (Reuters Health) – In patients with chronic hepatitis C genotype 4, adding nitazoxanide to peginterferon alfa-2a and ribavirin improves the virologic response rates, new research shows.

In the study, patients treated with the three-drug combination achieved a sustained virologic response rate of 79%, compared with a rate of only 50% in those given the standard of care, peginterferon plus ribavirin (p = 0.023). The sustained virologic response rate using nitazoxanide instead of ribavirin, with peginterferon, was 61%, according to the report in Gastroenterology for March.

“These results show that nitazoxanide, a novel protein kinase inducer, has the potential not only to increase the sustained virologic response rate but potentially to shorten the duration of therapy,” lead author Dr. Jean-Francois Rossignol, from Stanford University Medical Center, California, and colleagues state.

The study, conducted at two centers in Egypt, included 96 previously untreated patients who were randomized to receive peginterferon plus ribavirin for 48 weeks; nitazoxanide alone for 12 weeks and then combined with peginterferon for 36 weeks; or nitazoxanide alone for 12 weeks and then combined with peginterferon and ribavirin for 36 weeks.

Nitazoxanide was given twice daily at a dose of 500 mg, peginterferon once weekly at 180 micrograms, and ribavirin daily at 1000 to 1200 mg based on weight, the report indicates.

In additional to the higher sustained virologic response rate, the triple drug regimen also had a higher rapid virologic response rate, defined as the percentage of subjects with undetectable hepatitis C virus RNA at week 4. The rapid virologic response rates in the triple drug, peginterferon/ribavirin, and nitazoxanide/peginterferon groups were 64%, 38%, and 54%, respectively.

Aside from a higher rate of anemia in the groups receiving ribavirin, adverse events were similar in frequency and nature across the groups.

“The current study revealed provocative data in genotype 4 hepatitis C virus infection that will need additional confirmation in larger studies,” Drs. Jama M. Darling and Michael W. Fried, from the University of North Carolina, Chapel Hill, comment in a related editorial.

“The biggest unanswered question remains as to whether nitazoxanide is sufficiently potent to enhance therapeutic response in patients with difficult-to-treat characteristics, such as genotype 1, high viral levels, African Americans, and previous nonresponders to peginterferon and ribavirin, namely, those frequently found in the US population.”

Reference:
Gastroenterology 2009;136:760-763,856-862.