A multicenter study called WIN-R on hepatitis C patients, showed that the treatment with weight-based drugs resulted in improved efficacy and lower relapse rates, mainly in African-Americans with most difficult-to-treat form of the disease.
The study of over 5,000 patients with hepatitis C virus (HCV) showed that the treatment with weight-based REBETOL (ribavirin, USP) (RBV) in combination with pegylated interferon (PEG-IFN) alfa-2b, resulted in higher rates of sustained virologic response (SVR) and lower relapse rates, as compared to combination therapy using a flat dose of RBV 800 mg/day.
The response of such dose was a lot better in patients suffering from the most difficult-to-treat form of the disease, genotype 1 HCV.
However, the efficacy was consistent across all weight groups.
The study was led by Dr. Ira M. Jacobson, the Vincent Astor Professor of Clinical Medicine at Weill Cornell Medical College and chief of the Division of Gastroenterology and Hepatology at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.
For patients infected with genotype 2 or 3, a 24-week course of treatment with flat dose of RBV + PEG-IFN was equally effective as the standard 48-week course, with better tolerability.
In the overall study population, flat dosing of ribavirin was equally effective as weight-based ribavirin.
However, within the flat-dose group of patients with genotypes 2 and 3, sustained response rates showed a slight decline in the higher weight patients who were given flat-dosed ribavirin.
"These findings help define optimal therapy for U.S. hepatitis C patients," said Dr. Jacobson.
She added: "Our findings underscore that weight-based-dosed combination therapy is significantly more effective than the flat-dosed RBV regimen, especially in more difficult-to-treat patient groups, such as patients with genotype 1 and African-American patients. Patients being treated for hepatitis C should talk to their doctors to be sure they are receiving the most effective therapy."
According to a subanalysis of the WIN-R data evaluating the efficacy of weight-based dosing among African-American participants with genotype 1 infection, about twice the number of patients cleared the virus when treated with the weight-based RBV regimen as against the flat dose. Also, a lower rate was shown in the general study population with genotype 1 HCV.
"These results are particularly significant for African-Americans, a group with known lower rates of response to HCV therapy than reported in other ethnic groups. Weight-based dosing vs. flat dosing clearly showed the greatest therapeutic impact in this group," said Dr. Jacobson.
She added: "The study data strongly suggest adopting a 1400 mg/dose for patients who weigh more than 105 kg. In my opinion, the larger dose provides an opportunity for very heavy patients to have the same chance of cure as lighter patients without compromising safety."
The study is reported recently in the journal Hepatology.