Efficacy of Peginterferon Alfa-2b (PegIntron) vs. Peginterferon Alfa-2a (Pegasys) Plus Ribavirin Regimens in Treatment-naïve Chronic HCV Patients: A Meta-analysis

The objective of the current study was to elucidate differences in effectiveness of weight-based (alfa-2b) and fixed dose (alfa-2a) pegylated interferons + ribavirin (PEG-IFN+RIB) treatment regimens in treatment-naïve chronic HCV patients in settings outside of clinical trials.

European and US clinical investigators identified primarily through independent congress abstracts and collecting data under relevant institutional ethical guidelines were recruited to contribute de-identified data for meta-analysis.

Eligible patients were treatment-naïve adults with chronic HCV (G1, G2, or G3), receiving PEGIFN + RIB, consecutively treated since 1/2001. Patients in clinical trials, with HIV or HBV co-infection, or decompensated liver disease were excluded.

The primary efficacy measure was sustained viral response (SVR), i.e., absence of detectable HCV RNA 6 months after end of treatment response (EOTR).

Data were meta-analyzed using a hierarchical generalized linear model (HGLM) to control for patient- and site-level variation, and an adjusted odds ratio (OR) was calculated for the difference between PEG-IFNs.

Patient selection criteria and analytic methods were determined prospectively by an expert panel. Prognostic impact of treatment regimen, weight, site, baseline ALT quotient, age, gender, and race were assessed.

Results

• Six sites (2 US, 2 Germany, 2 Italy) contributed data, totaling 824 patients (61% male, 94% Caucasian, mean age 46, mean weight 76 kg).

• The two groups were comparable in terms of baseline characteristics and RIB dosing (mean 957 mg for PEGIFN alfa-2b, 987 mg PEG-IFN alfa-2a).
  
  
• SVR in G1 patients was significantly (p=0.017) higher for PEG-IFN alfa-2b (PegIntron) [plus ribavirin] vs. PEG-IFN alfa-2a (Pegasys) [plus ribavirin].

• Higher SVR rates were also achieved with PEG-IFN alfa-2b (PegIntron) for G2 and G3 patients, though this difference was not significant.
  
  
• Between-site heterogeneity was apparent in G2 and G3, but not G1, analyses.

In conclusion, the authors write, “Treatment with PEG-IFN alfa-2b has an advantage relative to PEG-IFN alfa-2a in the achievement of SVR in treatment-naïve adults with chronic HCV, G1.”

“Additional clinic sites are being identified through the literature to validate observations from this initial analysis.”

“Further analyses will evaluate secondary endpoints of early response, EOTR, and relapse, as well as incorporating additional patient covariates into the HGLM model.”

11/14/05

Reference
P L Almasio (for the HCV Meta-Analysis Working Group). Efficacy of PEG-IFN alfa-2b vs. PEG-IFN alfa-2a + ribavirin regimens in treatment-naïve chronic HCV patients: A cumulative meta-analysis of retrospective data from 6 clinic sites. Abstract 62599. 56^th annual meeting of the American Association for the Study of Liver Diseases (56^th AASLD). November 11-15, 2005. San Francisco, CA.