Response to treatment was defined as undetectable HCV RNA and normalization of ALT at 24 weeks post-treatment. The response rates to the 1.0 and 1.5 mg/kg PEG-Intron doses were similar (approximately 24%) to each other and were both higher than the response rate to INTRON A (12%). (See Table 1.)

TABLE 1. Rates of Response to Treatment-Study 1

^a Serum HCV is measured by a research-based quantitative polymerase chain reaction assay by a central laboratory.

Patients with both viral genotype 1 and high serum levels of HCV RNA at baseline were less likely to respond to treatment with PEG-Intron. Among patients with the two unfavorable prognostic variables, 8% (12/157) responded to PEG-Intron treatment and 2% (4/169) responded to INTRON A. Doses of PEG-Intron higher than the recommended dose did not result in higher response rates in these patients.

Patients receiving PEG-Intron with viral genotype 1 had a response rate of 14% (28/199) while patients with other viral genotypes had a 45% (43/96) response rate. Ninety-six percent of the responders in the PEG-Intron groups and 100% of responders in the INTRON A group first cleared their viral RNA by week-24 of treatment. (See DOSAGE AND ADMINISTRATION.)

The treatment response rates were similar in men and women. Response rates were lower in African American and Hispanic patients and higher in Asians compares to Caucasians. Although African Americans had a higher proportion of poor prognostic factors compared to Caucasians the number of non-Caucasians studied (9 percent of the total) was insufficient to allow meaningful conclusions about differences in response rates after adjusting for prognostic factors.

Liver biopsies were obtained before and after treatment in 60% of patients. A modest reduction in inflammation compared to baseline that was similar in all four treatment groups was observed.

A randomized study compared treatment with two PEG-Intron/REBETOL regimens [PEG-Intron 1.5 mg/kg SC once weekly (QW)/REBETOL 800 mg PO daily (in divided doses); PEG-Intron 1.5 mg/kg SC QW for 4 weeks then 0.5 mg/kg SC QW for 44 weeks/REBETOL 1000/1200 mg PO daily (in divided doses)] with INTRON A [3 MIU SC thrice weekly (TIW)/REBETOL 1000/1200 mg PO daily (in divided doses)] in 1530 adults with chronic hepatitis C. Interferon naive patients were treated for 48 weeks and followed for 24 weeks post-treatment. Eligible patients had compensated liver disease, detectable HCV RNA, elevated ALT, and liver histopathology consistent with chronic hepatitis.

Response to treatment was defined as undetectable HCV RNA at 24 weeks post-treatment. The response rate to the PEG-Intron 1.5 mg/kg plus ribavirin 800 mg dose was higher than the response rate to INTRON A/REBETOL (see Table 2). The response rate to PEG-Intron 1.5® 0.5mg/kg/REBETOL was essentially the same as the response to INTRON A/REBETOL (data not shown).

Bookmark this page: