By Liz Highleyman

Numerous studies have shown that people of African descent do not respond as well as Caucasians to interferon-based therapy for chronic hepatitis C virus (HCV) infection, but less is known about response rates in people of other racial/ethnic groups.

A recent multicenter study, described in the November 15, 2008 issue of Clinical Infectious Diseases, looked at combination therapy with pegylated interferon plus ribavirin in Asian patients.

A previous study found comparable sustained virological response (SVR) rates in Asian patients with HCV genotype 1 treated with pegylated interferon plus ribavirin for 24 weeks and white patients treated for 48 weeks, the study authors noted as background. But whether a 48-week course of combination therapy might produce at higher SVR rate than 24-week therapy in Asian patients has not been confirmed in large randomized studies.

In this multicenter trial, 308 previously untreated Asian patients with genotype 1 were randomly assigned to receive 180 mcg/week pegylated interferon alpha-2a (Pegasys) plus 1000-1200 mg/day ribavirin therapy for either 24 or 48 weeks.

The primary end point was SVR, defined as undetectable serum HCV RNA 24 weeks after completion of therapy. The investigators also assessed rapid virological response (RVR), defined as undetectable HCV RNA at week 4 of therapy, and complete early virological response (EVR), defined as undetectable HCV viral load at week 12 of therapy in the absence of RVR.

Results

• In an intent-to-treat analysis, patients who received 48 weeks of therapy had a significantly higher SVR rate than those treated for 24 weeks (76% vs 56%, respectively; P < 0.001).

• Among patients with a baseline HCV RNA level < 800,000 IU/mL and RVR, SVR rates were comparable in the 24-week and 48-week groups (94% vs 100%, respectively; P = 0.13, not a significant difference).

• In contrast, among patients who did not achieve RVR, 48 weeks of therapy was associated with a significantly higher SVR rate than 24 weeks of therapy (39% vs16%, respectively; P = 0.01).

• 48-week therapy was also significantly more effective among patients who achieved complete EVR (44% vs 20%, respectively; P = 0.02).

In treatment-naive Asian patients with HCV genotype 1, the investigators concluded, "48 weeks of pegylated interferon alpha-2a plus ribavirin therapy is associated with a higher SVR rate, compared with 24 weeks of such therapy."

"Patients with a baseline serum HCV RNA level < 800,000 IU/mL and who have achieved an RVR can receive a 24-week course of therapy without compromising the SVR rates," they continued. However, "those who have not achieved an RVR but who have achieved a complete early virologic response should receive a 48-week course of therapy."

National Taiwan University Hospital, Taipei, Taiwan; Taipei Municipal Hospital, Ren-Ai Branch, Taipei, Taiwan; Far Eastern Memorial Hospital, Taipei, Taiwan; Buddhist Tzu Chi General Hospital, Taipei Branch, Taipei, Taiwan; National Taiwan University Hospital, Yun-Lin Branch, Douliou, Taiwan; Taichung Veterans General Hospital, Taichung, Taiwan.

10/21/08

Reference
CH Liu, CJ Liu, CL Lin, and others. Pegylated interferon-alpha-2a plus ribavirin for treatment-naive Asian patients with hepatitis C virus genotype 1 infection: a multicenter, randomized controlled trial. Clinical Infectious Diseases 47(10): 1260-1269. November 15, 2008.