December 16, 2001
This global study by the Pegasys Group has never been presented before. It is based upon data provided to the FDA when Roche requested approval for Pegasys, which is now pending. Although the study only deals with monotherapy and the data on combination therapy was already presented at DDW last year, it has some interesting information.
It is important to mention that all the studies done by Roche have been reported and the data is available for comparison with the other pegylated drugs already on the market (e.g., PEG-Intron; we are still receiving new information about PEG-Intron which was approved early this past year).
Dr. Pockros presented the data on 639 patients. The patients received: interferon (IFN) alfa-2a TIW versus Pegasys 135 mg and Pegasys 180 mg. The study was done in 52 centers worldwide for 48 weeks. The majority of the patients were caucasian and non-cirrhotic. Sixty-five percent were diagnosed with genotype 1 and 35 percent with genotype 2.
The end of therapy response, defined as the response at the end of the scheduled 48 weeks of therapy, was 22 percent for the IFN arm, 53 percent for the Pegasys 135 mg arm and 55 percent for the Pegasys 180 mg arm. The sustained response was: 11 percent, 28 percent and 28 percent, respectively.
When the groups were divided according to genotype, genotype 1 was: 7 percent, 19 percent and 22 percent, respectively; as compared to genotype 2: 19 percent, 45 percent and 41 percent, respectively. The histological improvement was of the order of 45 percent, 48 percent and 58 percent, respectively.
This study also showed the predictability of a sustained response in early responders; hepatitis C response or a 2 log decrease at week 12 predicts sustained response even in the genotype 1 patients.
Dr. Pockros clearly noted that only the patients receiving the full dose of Pegasys had a benefit in histology superior to standard IFN. This is very important because although 135 mg is effective, the ideal dose is 180 mg. Patients taking a reduced dose of Pegasys are receiving less than optimal treatment. This also may explain the differences in the sustained responses between the study trials. Patients and physicians may be less tolerant of adverse events or patients more sensitive to the drug, resulting in more drug dose reductions. The differences in the sustained responses with Pegasys range between 36 percent to 28 percent in this study. The analysis of the studies show that they differ in the percentage of minorities, especially African Americans, percentage of cirrhotics, and the amount of dose modifications. It seems that the "American trials" have more dose decreases. This may indicate that we need to evaluate the amount of information and support that we give to our patients before and during therapy.
It will be of no benefit to use the best pegylated IFN -- which has been shown to be Pegasys -- if the patient is not motivated and compromised to follow the treatment properly, and worse, if the physician thinks that his or her work is finished when the patient starts therapy.
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