Early Anti-HCV Activity of Pegasys and PegIntron Are Similar in HIV-HCV Coinfected Patients

Current treatment for chronic hepatitis C for both HCV monoinfected and HIV-HCV coinfected patients is pegylated interferon plus ribavirin. There are 2 forms of pegylated interferon available -- peginterferon alfa-2a (Pegasys) and peginterferon alfa-2b (PegIntron) -- but little data about their relative efficacy.

As reported at the recent 58th Annual Meeting of the American Association for the Study of Liver Diseases in Boston (November 2-6, 2007), investigators at Hospital Carlos III in Madrid, Spain, conducted a comparative study of virological response to Pegasys and PegIntron in coinfected patients.

The analysis included all consecutive HIV-HCV coinfected patients at the hospital who initiated first-line treatment with either Pegasys or PegIntron, both with 1000-1200 mg/day weight-based ribavirin. A total of 207 patients were identified, of whom 138 received Pegasys and 69 received PegIntron.

Baseline characteristics in the 2 groups were similar: age about 45 years, about 75% male, mean body mass index about 23 kg/m2, mean CD4 count about 535 cells/mm3, 70%-80% with undetectable HIV RNA (<50 copies/mL), mean HCV RNA about 6.1 log IU/mL, about 70% with HCV genotype 1, and mean liver stiffness by transient elastometry (FibroScan) was about 10 Kpa.

Rapid virological response (RVR) at week 4, early virological response (EVR) at week 12, and undetectable HCV RNA (<10 IU/mL) at week 24 were assessed using an intent-to-treat analysis. Baseline liver fibrosis was estimated using transient elastometry. Plasma trough concentrations of ribavirin were measured at week 12, and were similar in the Pegasys and PegIntron groups.

Results

• At week 4, the mean HCV RNA decay was 2.7 log IU/mL in the Pegasys group and 2.2 log IU/mL in the PegIntron group (P=0.09).

• At week 12, the HCV RNA declines were 4.5 and 4.3 log IU/mL, respectively (P=0.5).

• At week 24, the corresponding declines were 3.7 and 3.2 log IU/mL, respectively (P=0.1).

• 43% of patients in the Pegasys group achieved RVR, compared with 30% in the PegIntron group (P=0.08).

• For EVR, the corresponding rates were 71% and 70%, respectively (P=0.8).

• 64% of patients taking Pegasys and 58% of those taking PegIntron had undetectable HCV RNA at week 24 (P=0.4).

• The RVR rate was higher with Pegasys compared with PegIntron among patients with a high baseline HCV viral load (> 500,000 IU/mL) (37% vs 15%; P=0.01) and in patients with HCV genotypes 2 or 3 (85% vs 56%: P=0.02).

• In a multivariate model, greater ribavirin plasma concentrations predicted RVR, EVR, and week 24 response, independent of the type of pegylated interferon used.

• The positive predictive value of ribavirin levels >2.1 mcg/mL for week 24 response was 82%.

Conclusion

"The intrinsic antiviral activity of pegylated interferon alfa-2a and -2b seems to be comparable, except for the very early phase of viral decay," the investigators concluded.

However, they added, "In this study higher ribavirin plasma concentrations rather than the pegylated interferon modality were the main determinant of virological response at any time point."

12/04/07

Reference
P Barreiro, E Vispo, S Rodriguez-Novoa, and others. Early Hepatitis C Virus Decay with Weight-Based Ribavirin Plus Either PegIFN?-2a or PegIFN?-2b in HIV/HCV Coinfected Patients. 58th Annual Meeting of the American Association for the Study of Liver Diseases. Boston, MA, November 2-6, 2007. Abstract 257.