All-trans retinoic acid with daunorubicin or idarubicin for risk-adapted treatment of acute promyelocytic leukaemia: a matched-pair analysis of the PETHEMA LPA-2005 and IC-APL studies.

Front-line treatment of acute promyelocytic leukaemia (APL) consists of all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. In this setting, a comparison of idarubicin and daunorubicin has never been carried out. Two similar clinical trials using ATRA and chemotherapy for newly diagnosed APL were compared using matched-pair analysis. One was conducted by the PETHEMA/HOVON group with idarubicin and the other by the International Consortium on APL (IC-APL) using daunorubicin. Three hundred and fifty patients from the PETHEMA/HOVON cohort were matched with 175 patients in the IC-APL cohort, adjusting for the significantly unbalanced presenting features of the two entire cohorts. Complete remission (CR) rate was significantly higher in the PETHEMA/HOVON (94 %) than in the IC-APL cohort (85 %) (P = 0.002). The distribution of causes of induction failure and the time to achieve CR were similar in both cohorts. Patients who achieved CR had comparable cumulative incidence of relapse and disease-free survival rates, but lower overall and event-free survivals were observed in the IC-APL cohort, which was mainly due to a higher death rate during induction therapy. A higher death rate during consolidation therapy was also observed in the IC-APL. These results show that daunorubicin and idarubicin have similar antileukaemic efficacy in terms of primary resistance, molecular persistence, as well as molecular and haematological relapse rates when combined with ATRA in treatment of APL. However, a higher toxic death rate during induction and consolidation therapy was observed in the IC-APL cohort. This trial was registered at www.clinicaltrials.gov as #NCT00408278 [ClinicalTrials.gov].

Risk-adapted treatment of acute promyelocytic leukemia based on all-trans retinoic acid and anthracycline with addition of cytarabine in consolidation therapy for high-risk patients: further improvements in treatment outcome.

A risk-adapted strategy based on all-trans retinoic acid (ATRA) and anthracycline monochemotherapy (PETHEMA LPA99 trial) has demonstrated a high antileukemic efficacy in acute promyelocytic leukemia. We designed a new trial (LPA2005) with the objective of achieving stepwise improvements in outcome. Between July 2005 and April 2009, low- and intermediate-risk patients (leukocytes < 10 x 10(9)/L) received a reduced dose of mitoxantrone for the second consolidation course, whereas high- risk patients younger than 60 years of age received cytarabine combined with ATRA and idarubicin in the first and third consolidation courses. Of 372 patients attaining complete remission after ATRA plus idarubicin (92.5%), 368 proceeded to consolidation therapy. For low- and intermediate-risk patients, duration of neutropenia and thrombocytopenia and hospital stay were significantly reduced without sacrificing antileukemic efficacy, compared with the previous LPA99 trial. For high-risk patients, the 3-year relapse rate was significantly lower in the LPA2005 trial (11%) than in the LPA99 (26%; P = .03). Overall disease-free survival was also better in the LPA2005 trial (P = .04). In conclusion, the lower dose of mitoxantrone resulted in a significant reduction of toxicity and hospital stay while maintaining the antileukemic activity, and the combination of ATRA, idarubicin, and cytarabine for high-risk acute promyelocytic leukemia significantly reduced the relapse rate in this setting. Registered at http://www.clinicaltrials.gov as NCT00408278.