CPX-351 versus 7+3 cytarabine and daunorubicin chemotherapy in older adults with newly diagnosed high-risk or secondary acute myeloid leukaemia: 5-year results of a randomised, open-label, multicentre, phase 3 trial

Background Daunorubicin and cytarabine are used as standard induction chemotherapy for patients with acute myeloid leukaemia. CPX-351 is a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio. Primary analysis of the phase 3 trial in adults aged 60-75 years with newly diagnosed high-risk or secondary acute myeloid leukaemia provided support for approval of CPX-351 by the US Food and Drug Administration and European Medicines Agency. We describe the prospectively planned final 5-year follow-up results. Methods This randomised, open-label, multicentre, phase 3 trial was done across 39 academic and regional cancer centres in the USA and Canada. Eligible patients were aged 60-75 years and had a pathological diagnosis of acute myeloid leukaemia according to WHO 2008 criteria, no previous induction therapy for acute myeloid leukaemia, and an Eastern Cooperative Oncology Group performance status of 0-2. Patients were randomly assigned 1:1 (stratified by age and acute myeloid leukaemia subtype) to receive up to two induction cycles of CPX-351 (100 units/m(2) administered as a 90-min intravenous infusion on days 1, 3, and 5; on days 1 and 3 for the second induction) or standard chemotherapy (cytarabine 100 mg/m(2) per day continuous intravenous infusion for 7 days plus intravenous daunorubicin 60 mg/m(2) on days 1, 2, and 3 [7+3]; cytarabine for 5 days and daunorubicin on days 1 and 2 for the second induction [5+2]). Patients with complete remission or complete remission with incomplete neutrophil or platelet recovery could receive up to tw cycles of consolidation therapy with CPX-351 (65 units/m(2) 90-min infusion on days 1 and 3) or chemotherapy (5+2, same dosage as in the second induction cycle). The primary outcome was overall survival analysed in all randomly assigned patients. No additional adverse events were collected with long-term follow-up, except data for deaths. This trial is registered with ClinicalTrials.gov, NCT01696084, and is complete. Findings Between Dec 20, 2012, and Nov 11, 2014, 309 patients with newly diagnosed high-risk or secondary acute myeloid leukaemia were enrolled and randomly assigned to receive CPX-351 (153 patients) or 7+3 (156 patients). At a median follow-up of 60.91 months (IQR 60.06-62.98) in the CPX-351 group and 59.93 months (59.73-60.50) in the 7+3 group, median overall survival was 9.33 months (95% CI 6.37-11.86) with CPX-351 and 5.95 months (4.99-7.75) with 7+3 (HR 0.70, 95% CI 0.55-0.91). 5-year overall survival was 18% (95% CI 12-25%) in the CPX-351 group and 8% (4-13%) in the 7+3 group. The most common cause of death in both groups was progressive leukaemia (70 [56%] of 124 deaths in the CPX-351 group and 74 [53%] of 140 deaths in the 7+3 group). Six (5%) of 124 deaths in the CPX-351 group and seven (5%) of 140 deaths in the 7+3 group were considered related to study treatment. Interpretation After 5 years of follow-up, the improved overall survival with CPX-351 versus 7+3 was maintained, which supports the previous evidence that CPX-351 can contribute to long-term remission and improved overall survival in patients aged 60-75 years with newly diagnosed high-risk or secondary acute myeloid leukaemia. Copyright (C) 2021 Elsevier Ltd. All rights reserved.