Multicenter phase 3 trial of first-line nilotinib with or without pegylated interferon alfa-2a for CP-CML: final results from PETALs

The phase 3 PETALs trial, at 27 centers in France, randomized adult patients with newly diagnosed chronic phase chronic myeloid leukemia (CP-CML) to oral nilotinib 300 mg twice daily alone (n=99) or nilotinib 300 mg twice daily plus weekly subcutaenous pegylated interferon alfa-2a (Peg-IFN; n=101) for a maximum of 2 years. Eligible patients had major BCR::ABL1 transcripts and an EGOG performance status of 2 or better. The primary endpoint was the cumularive rate of molecular response 4.5 (MR4.5). Median duration of follow-up was 67 months (IQR 32.6-70.6). The primary objective was met, with higher rates of MR4.5 in the combination group (24% versus 15%; p=0.048) at month 12. There were 14 grade 3-4 hematological side effects in each group. Psychiatric grade 3-4 events occurred in six patients in the combination group (including three unsuccessful suicide attempts) compared with five in the nilotinib alone group (one unsuccessful suicide attempt). Grade 3-4 vascular events occurred in six patients in the combination group and five patients in the nilotinib alone group. The authors conclude that, in this, setting, Peg-IFN combined with nilotinib induced higher additional rates of MR4.5 compared with nilotinib alone.