The PINNACLE study: A multicentre phase II trial of nilotinib in combination with pegylated interferon-α2b in newly diagnosed chronic phase chronic myeloid leukaemia.

We evaluated the tolerability and efficacy of pegylated interferon alfa-2B (peg-IFNα; PegIntron, MSD) combined with nilotinib in the Australasian Leukaemia and Lymphoma Group CML11 (Pinnacle) study. This phase II study started patients on nilotinib 300 mg twice daily. Subcutaneous peg-IFNα was added at 30-50 50 μg/week from 3 months until 24 months as tolerated. Sixty patients were enrolled with a median age of 48.5 years (range 19-72); 45% were female. With a median follow-up of 60 months, 40 patients (67%) remain on study. The proportion of patients who received ≥50% and ≥85% of their assigned peg-IFNα doses were 58% and 35% respectively. Common reasons for peg-IFNα discontinuation were mood disturbance (5), thyroid disease (4) and myalgia (4). The cumulative incidence of Major Molecular Response (MMR, BCR::ABL1≤0.1%) was 87% by 12 months; Molecular Response 4.5 (MR4.5, BCR::ABL1≤0.0032%) incidence at 24 and 60 months was 55% and 82% respectively. Thirty-seven patients (62%) had MR4.5 for >24 months, 14 of whom attempted treatment-free remission (TFR); 13 remained in TFR at a median follow-up of 32 months. CML11 demonstrated that peg-IFNα with nilotinib leads to high rates of molecular response, with tolerability similar to prior studies. Trial registration ANZCTRN12612000851864.