By Liz Highleyman

Given the side effects and cost of interferon-based therapy for chronic hepatitis C virus (HCV) infection, researchers continue to explore shorter treatment durations, especially for individuals who respond rapidly after starting therapy.

The current standard of care is 24 weeks of pegylated interferon plus ribavirin for chronic hepatitis C patients with HCV genotypes 2 or 3, while those with hard-to-treat genotypes 1 or 4 are treated for 48 weeks. Many experts recommend longer therapy for individuals with HIV-HCV coinfection.

In a study described in the August 2008 issue of Gastroenterology, Peter Ferenci and colleagues from Austria aimed to determine whether 24 weeks might be adequate for patients with HCV genotype 1 or 4 who achieve rapid virological response (RVR), or undetectable after 4 weeks of therapy.

The study initially included 516 genotype 1 or 4 patients treated with 180 mcg/week pegylated interferon alfa-2a (Pegasys) plus 1000-1200 mg/day weight-based ribavirin. Participants who did not achieve RVR (HCV RNA < 50 copies/mL) at week 4 were randomly assigned to receive 48 or 72 weeks of treatment (this part of the study was ongoing at the time of the report).

Among those who did achieve RVR, the investigators analyzed rates of sustained virological response (SVR), or continued undetectable HCV viral load 24 weeks after completion of therapy.

Results

• 150 of the 516 patients (26%) achieved RVR.

• 143 of the 150 completed 24 weeks of treatment.

• The overall SVR rate in this subgroup was 80.4%:

• 78.8% for genotype 1;
• 86.7% for genotype 4.

• The following factors were predictive of RVR:

• younger age;
• lower body fat;
• low baseline HCV RNA (< 400,000 IU/mL);
• HCV genotype 4 rather than 1.

• However, once a person had achieved RVR, no baseline factors significantly predicted SVR.

• Treatment was well tolerated overall.

Based on these findings, the investigators concluded, "This prospective study confirms that a 24-week regimen of peginterferon alfa-2a plus ribavirin 1000-1200 mg/day is appropriate in genotype 1 and 4 patients with a low baseline HCV RNA level who achieve an RVR by week 4 of therapy."

Medical University, Vienna, Austria; Kaiser-Franz-Josef-Spital, Vienna, Austria; Wilhelminenspital, Vienna, Austria; Elisabethinen Hospital, Linz, Austria; Hospital Hietzing, Vienna, Austria; Medical University, Graz, Austria; Rudolfshospital, Vienna, Austria; LKH Hörgas-Enzenbach, Gratwein, Austria; Krankenhaus, Oberndorf, Austria; Roche Austria, Vienna, Austria.

10/14/08

Reference
P Ferenci, H Laferl, TM Scherzer, and others. Peginterferon alfa-2a and ribavirin for 24 weeks in hepatitis C type 1 and 4 patients with rapid virological response. Gastroenterology 135(2): 451-458. August 2008. (Abstract).