Phase II, randomized, multicenter, comparative study of peginterferon-alpha-2a (40 kD) (Pegasys (R)) versus interferon alpha-2a (Roferon (R)-A) in patients with treatment-naive, chronic-phase chronic myelogenous leukemia

The efficacy and safety of peginterferon-alpha-2 alpha (40 kD) (PEG-IFN alpha-2a), 450 mu g once weekly, versus IFN alpha-2a, 9 MIU once daily, for 12 months, was evaluated in a Phase II study in IFN-naive patients with chronic-phase, Philadelphia-chromosome-positive CML. At the end of the treatment, complete hematological response was observed in 66.2% (47/71) and 45.2% (33/73) of the PEG-IFN alpha-2a group and IFN alpha-2a groups, respectively (p = 0.009), and major cytogenetic response occurred in 35.2% and 17.8%, respectively (p = 0.016). PEG-IFN alpha-2a was at least as effective as IFN alpha-2a overall, including progression-free survival at the end of treatment, and overall survival after 30 months of follow-up. Adverse events necessitated fewer withdrawals but more dose adjustments in the PEG-IFN alpha-2a group compared with the IFN alpha-2a group (11% versus 23%, and 84.5% versus 65.8%, respectively). In conclusion, PEG-IFN alpha-2a (40 kD), 450 mg once weekly, compared with IFN alpha-2a, 9 MIU once daily, resulted in higher rates of hematologic and cytogenetic response and greater overall survival.