AASLD: Weight-Based Dosing of Rebetol Improves Outlook for HCV

November 18, 2005

By , MedPage Today Staff Writer

Reviewed by Rubeen K. Israni, M.D., Fellow, Renal-Electrolyte and

Hypertension Division, University of Pennsylvania School of Medicine

November 17, 2005

MedPage Today Action Points

Note that the combination of daily Rebetol at 800 mg and PEG-Intron (1.5

mcg/kg/week) is regarded as the standard of care for HCV infection

Advise interested patients that this study is intended to refine the way the

treatment is delivered.

This study was published as an abstract and presented orally at a

conference. These data and conclusions should be considered to be

preliminary as they have not yet been reviewed and published in a

peer-reviewed publication.

Review

SAN FRANSICO, Nov. 17 - Giving Rebetol (ribavirin) based on the weight of a

chronic hepatitis C (HCV) patient, rather than a flat dose, resulted in

better viral control and fewer relapses, researchers reported here.

In what researchers said was the largest therapeutic trial in hepatitis C

(HCV), 4.913 patients were randomized to PEG-Intron (peginterferon alfa-2b)

once a week and either a flat daily dose of 800 mg of Rebetol or one of four

daily doses based on weight:

800 mg for patients weighing less than 65 kg

1,000 mg for patients between 65 and 85 kg

1,200 mg for patients between 85 and 105 kg

And 1,400 mg for patients between 105 and 125 kg

The PEG-Intron dose was 1.5 mcg/kg/week.

The combination of Rebetol and PEG-Intron has been established as the

standard of care for chronic HCV, Ira son, M.D., of Weill Cornell

Medical College in New York reported at the American Association for the

Study of Liver Diseases meeting.

" These findings help further define optimal therapy, " he said.

Dr. son presented the final results of the Weight-Based Dosing of

PEG-Intron and Rebetol (WIN-R) study, which involved 225 centers across the

U.S.

All HCV genotype 1 patients were given 48 weeks of therapy while genotype 2

and 3 patients were randomized to either 24 or 48 weeks of therapy. Patient

HCV RNA was checked at 24, 48, and 72 weeks. A sustained virologic response

(SVR) is defined as undetectable virus at 24 weeks after completing therapy.

In an intention-to-treat analysis, the study found:

Overall, a sustained virologic response of 44.3% in the weight-based arm,

versus 40.6% in the flat-dose arm. The result was statistically significant

(p=0.01).

For patients with genotype 1, an SVR of 34% versus 29%, statistically

significant (p=0.004). For patients with genotype 2, the rates were 32% and

27% (p=0.047). There was no difference in SVR for patients with genotype 3.

For patients with HCV genotypes 2 or 3, a 24-week course of the combination

therapy was as effective as 48 weeks, with better tolerability.

Overall, 15% of patients on the weight-based regimen relapsed, compared with

19% in the flat-dose arm, where relapse was defined as having undetectable

virus levels at the end of treatment, but detectable virus 24 weeks later.

Serious adverse events were 11% in both arms, Dr. son reported. There

was a higher rate of anemia (defined as hemoglobin less than 10 g/dL) in the

weight-based arm -- 46% versus 32%.

All told 1,808 patients stopped treatment -- 15% for adverse events, 7% for

lack of efficacy, and 15% for non-medical reasons.

If those who discontinued for adverse events or non-medical reasons are

excluded, the SVR for the weight-based arm is 56% compared with 51% for the

flat-dose arm, Dr. son reported. The difference is statistically

significant (p=0.005).

Primary source: 2005 AASLD Meeting

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November 18, 2005