Comparison of biochemical safety between PEG-IFN alpha-2a and PEG-IFN alpha-2b.

Background/aims: Although the efficacy and safety of pegylated-interferon (PEG-IFN) alpha-2a and PEG-IFN alpha-2b have been comparatively studied, there are few study results available in which the two PEG-IFN products were strictly compared. To compare the effects of two PEG-IFN products on blood cell profile.
Methodology: The time-course change in blood cell counts was compared between chronic hepatitis C patients with genotype 1b receiving PEG-IFN alpha-2a/ribavirin and PEG-IFN alpha-2b/ribavirin combination therapy. The comparison was made after matching patients from the two groups based on ribavirin apparent clearance (CL/F), a surrogate marker of the steady state blood ribavirin level, in order to eliminate the effect of ribavirin. Fifteen pairs of matched patients were selected.
Results: The time-course change in hemoglobin did not differ significantly between the two groups. However, significantly greater reductions in both neutrophil and platelet counts were observed with PEG-IFN alpha-2a compared to PEG-IFN alpha-2b. A slightly longer period was required with PEG-IFN alpha-2a than with PEG-IFN alpha-2b for a reduction in neutrophil or platelet count large enough to necessitate dose reduction.
Conclusions: Two types of PEG-IFN products affected the blood cell profile in different manners. Long-term monitoring of laboratory test values is necessary with PEG-IFN alpha-2a.