Clinical significance of CD56 expression in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline-based regimens.

The expression of CD56 antigen in acute promyelocytic leukemia (APL) blasts has been associated with short remission duration and extramedullary relapse. We investigated the clinical significance of CD56 expression in a large series of patients with APL treated with all-trans retinoic acid and anthracycline-based regimens. Between 1996 and 2009, 651 APL patients with available data on CD56 expression were included in 3 subsequent trials (PETHEMA LPA96 and LPA99 and PETHEMA/HOVON LPA2005). Seventy-two patients (11%) were CD56(+) (expression of CD56 in ≥ 20% leukemic promyelocytes). CD56(+) APL was significantly associated with high white blood cell counts; low albumin levels; BCR3 isoform; and the coexpression of CD2, CD34, CD7, HLA-DR, CD15, and CD117 antigens. For CD56(+) APL, the 5-year relapse rate was 22%, compared with a 10% relapse rate for CD56(-) APL (P = .006). In the multivariate analysis, CD56 expression retained the statistical significance together with the relapse-risk score. CD56(+) APL also showed a greater risk of extramedullary relapse (P < .001). In summary, CD56 expression is associated with the coexpression of immaturity-associated and T-cell antigens and is an independent adverse prognostic factor for relapse in patients with APL treated with all-trans-retinoic acid plus idarubicin-derived regimens. This marker may be considered for implementing risk-adapted therapeutic strategies in APL. The LPA2005 trial is registered at http://www.clinicaltrials.gov as NCT00408278.

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.

Does microgranular variant morphology of acute promyelocytic leukemia independently predict a less favorable outcome compared with classical M3 APL? A joint study of the North American Intergroup and the PETHEMA Group.

Few studies have examined the outcome of large numbers of patients with the microgranular variant (M3V) of acute promyelocytic leukemia (APL) in the all-trans retinoic acid era. Here, the outcome of 155 patients treated with all-trans retinoic acid-based therapy on 3 clinical trials, North American Intergroup protocol I0129 and Programa para el Estudio de la Terapéutica en Hemopatía Maligna protocols LPA96 and LPA99, are reported. The complete remission rate for all 155 patients was 82%, compared with 89% for 748 patients with classical M3 disease. The incidence of the APL differentiation syndrome was 26%, compared with 25% for classical M3 patients, and the early death rate was 13.6% compared with 8.4% for patients with classical M3 morphology. With a median follow-up time among survivors of 7.6 years (range 3.6-14.5), the 5-year overall survival, disease-free survival, and cumulative incidence of relapse for patients with M3V were 70%, 73%, and 24%, respectively. With a median follow-up time among survivors of 7.6 years (range 0.6-14.3), the 5-year overall survival, disease-free survival, and cumulative incidence of relapse among patients with classical M3 morphology were 80% (P = .006 compared with M3V), 81% (P = .07), and 15% (P = .005), respectively. When outcomes were adjusted for the white blood cell count or the relapse risk score, none of these outcomes were significantly different between patients with M3V and classical M3 APL.

Differentiation syndrome in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline chemotherapy: characteristics, outcome, and prognostic factors.

Differentiation syndrome (DS) can be a life-threatening complication in patients with acute promyelocytic leukemia (APL) undergoing induction therapy with all-trans retinoic acid (ATRA). Detailed knowledge about DS has remained limited. We present an analysis of the incidence, characteristics, prognostic factors, and outcome of 739 APL patients treated with ATRA plus idarubicin in 2 consecutive trials (Programa Español de Tratamientos en Hematología [PETHEMA] LPA96 and LPA99). Overall, 183 patients (24.8%) experienced DS, 93 with a severe form (12.6%) and 90 with a moderate form (12.2%). Severe but not moderate DS was associated with an increase in mortality. A bimodal incidence of DS was observed, with peaks occurring in the first and third weeks after the start of ATRA therapy. A multivariate analysis indicated that a WBC count greater than 5 x 10(9)/L and an abnormal serum creatinine level correlated with an increased risk of developing severe DS. Patients receiving systematic prednisone prophylaxis (LPA99 trial) in contrast to those receiving selective prophylaxis with dexamethasone (LPA96 trial) had a lower incidence of severe DS. Patients developing severe DS showed a reduced 7-year relapse-free survival in the LPA96 trial (60% vs 85%, P = .003), but this difference was not apparent in the LPA99 trial (86% vs 88%).

Risk-adapted treatment of acute promyelocytic leukemia with all-trans retinoic acid and anthracycline monochemotherapy: long-term outcome of the LPA 99 multicenter study by the PETHEMA Group.

A previous report of the Programa de Estudio y Tratamiento de las Hemopatías Malignas (PETHEMA) Group showed that a risk-adapted strategy combining all-trans retinoic acid (ATRA) and anthracycline monochemotherapy for induction and consolidation in newly diagnosed acute promyelocytic leukemia results in an improved outcome. Here we analyze treatment outcome of an enlarged series of patients who have been followed up for a median of 65 months. From November 1999 through July 2005 (LPA99 trial), 560 patients received induction therapy with ATRA plus idarubicin. Patients achieving complete remission received 3 courses of consolidation followed by maintenance with ATRA and low-dose chemotherapy. The 5-year cumulative incidence of relapse and disease-free survival were 11% and 84%, respectively. These results compare favorably with those obtained in the previous LPA96 study (P = .019 and P = .04, respectively). This updated analysis confirms the high antileukemic efficacy, low toxicity, and high degree of compliance of a risk-adapted strategy combining ATRA and anthracycline monochemotherapy for consolidation therapy.

Additional chromosome abnormalities in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy.

BACKGROUND: Acute promyelocytic leukemia is a subtype of acute myeloid leukemia characterized by the t(15;17). The incidence and prognostic significance of additional chromosomal abnormalities in acute promyelocytic leukemia is still a controversial matter. DESIGN AND METHODS: Based on cytogenetic data available for 495 patients with acute promyelocytic leukemia enrolled in two consecutive PETHEMA trials (LPA96 and LPA99), we analyzed the incidence, characteristics, and outcome of patients with acute promyelocytic leukemia with and without additional chromosomal abnormalities who had been treated with all-trans retinoic acid plus anthracycline monochemotherapy for induction and consolidation. RESULTS: Additional chromosomal abnormalities were observed in 140 patients (28%). Trisomy 8 was the most frequent abnormality (36%), followed by abn(7q) (5%). Patients with additional chromosomal abnormalities more frequently had coagulopathy (P=0.03), lower platelet counts (P=0.02), and higher relapse-risk scores (P=0.02) than their counterparts without additional abnormalities. No significant association with FLT3/ITD or other clinicopathological characteristics was demonstrated. Patients with and without additional chromosomal abnormalities had similar complete remission rates (90% and 91%, respectively). Univariate analysis showed that additional chromosomal abnormalities were associated with a lower relapse-free survival in the LPA99 trial (P=0.04), but not in the LPA96 trial. However, neither additional chromosomal abnormalities overall nor any specific abnormality was identified as an independent risk factor for relapse in multivariate analysis. CONCLUSIONS: The lack of independent prognostic value of additional chromosomal abnormalities in acute promyelocytic leukemia does not support the use of alternative therapeutic strategies when such abnormalities are found.

Central nervous system involvement at first relapse in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy without intrathecal prophylaxis.

BACKGROUND: The prevalence of and risk factors for central nervous system recurrence in patients with acute promyelocytic leukemia are not well established and remain a controversial matter. DESIGN AND METHODS: Between 1996 and 2005, 739 patients with newly diagnosed acute promyelocytic leukemia enrolled in two consecutive trials (PETHEMA LPA96 and LPA99) received induction therapy with all-trans retinoic acid and idarubicin. Consolidation therapy comprised three courses of anthracycline monochemotherapy (LPA96), with all-trans retinoic acid and reinforced doses of idarubicin in patients with an intermediate or high risk of relapse (LPA99). Central nervous system prophylaxis was not given. RESULTS: Central nervous system relapse was documented in 11 patients. The 5-year cumulative incidence of central nervous system relapse was 1.7% (LPA96 3.2% and LPA99 1.2%; p=0.09). The cumulative incidence was 0%, 0.8%, and 5.5% in low-, intermediate-, and high-risk patients, respectively. Relapse risk score (p=0.0001) and the occurrence of central nervous system hemorrhage during induction (5-year cumulative incidence 18.7%, p=0.006) were independent risk factors for central nervous system relapse. CONCLUSIONS: This study shows a low incidence of central nervous system relapse in patients with acute promyelocytic leukemia following therapy with all-trans retinoic acid and anthracycline without specific central nervous system prophylaxis. Central nervous system relapse was significantly associated with high white blood cell counts and prior central nervous system hemorrhage, which emerged as independent prognostic factors.

Therapy-related myeloid neoplasms in patients with acute promyelocytic leukemia treated with all-trans-retinoic Acid and anthracycline-based chemotherapy.

PURPOSE: We analyzed the incidence, risk factors, and outcome of therapy-related myeloid neoplasms (t-MNs) in patients with acute promyelocytic leukemia (APL) in first complete remission (CR). PATIENTS AND METHODS: From 1996 to 2008, 1,025 patients with APL were enrolled onto three sequential trials (LPA96, LPA99, and LPA2005) of the Programa Español para el Tratamiento de Enfermedades Hematológicas and received induction and consolidation therapy with all-trans-retinoic acid (ATRA) and anthracycline-based chemotherapy. RESULTS: Seventeen of 918 patients who achieved CR developed t-MN (10 with < 20% and seven with > or = 20% of bone marrow blasts) after a median of 43 months from CR. Partial and complete deletions of chromosomes 5 and 7 (nine patients) and 11q23 rearrangements (three patients) were the most common cytogenetic abnormalities. Overall, the 6-year cumulative incidence of t-MN was 2.2%, whereas in low-, intermediate-, and high-risk patients, the 6-year incidence was 5.2%, 2.1%, and 0%, respectively. Multivariate analysis identified age more than 35 years and lower relapse risk score as independent prognostic factors for t-MN. The median overall survival time after t-MN was 10 months. CONCLUSION: t-MN is a relatively infrequent, long-term, and severe complication after first-line treatment for APL with ATRA and anthracycline-based regimens. Therapeutic strategies to reduce the incidence of t-MN are warranted.

Causes and prognostic factors of remission induction failure in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and idarubicin.

An understanding of the prognostic factors associated with the various forms of induction mortality in patients with acute promyelocytic leukemia (APL) has remained remarkably limited. This study reports the incidence, time of occurrence, and prognostic factors of the major categories of induction failure in a series of 732 patients of all ages (range, 2-83 years) with newly diagnosed APL who received all-trans retinoic acid (ATRA) plus idarubicin as induction therapy in 2 consecutive studies of the Programa de Estudio y Tratamiento de las Hemopatias Malignas (PETHEMA) Group. Complete remission was attained in 666 patients (91%). All the 66 induction failures were due to induction death. Hemorrhage was the most common cause of induction death (5%), followed by infection (2.3%) and differentiation syndrome (1.4%). Multivariate analysis identified specific and distinct pretreatment characteristics to correlate with an increased risk of death caused by hemorrhage (abnormal creatinine level, increased peripheral blast counts, and presence of coagulopathy), infection (age>60 years, male sex, and fever at presentation), and differentiation syndrome (Eastern Cooperative Oncology Group [ECOG] score>1 and low albumin levels), respectively. These data furnish clinically relevant information that might be useful for designing more appropriately risk-adapted treatment protocols aimed at reducing the considerable problem of induction mortality in APL.

Risk-adapted treatment of acute promyelocytic leukemia with all-trans-retinoic acid and anthracycline monochemotherapy: a multicenter study by the PETHEMA group.

All-trans-retinoic acid (ATRA) increases the efficacy of chemotherapy when used for induction and maintenance treatment of acute promyelocytic leukemia (APL), but its role in consolidation is unknown. Since November 1996, 426 patients with newly diagnosed APL have received induction therapy with ATRA and idarubicin. Before November 1999 (LPA96 study), consolidation therapy consisted of 3 courses of anthracycline monochemotherapy. After November 1999 (LPA99 study), patients with intermediate and high risks of relapse received consolidation therapy with ATRA and increased doses of anthracyclines. Of the 384 patients who achieved complete remission (90%), 382 proceeded to consolidation therapy. Seven patients died in remission (1.8%). The 3-year cumulative incidence of relapse for patients in the LPA96 and LPA99 studies was 17.2% and 7.5%, respectively (P =.008). Patients treated with ATRA in consolidation therapy showed an overall reduction in the relapse rate from 20.1% to 8.7% (P =.004). In intermediate-risk patients the rate decreased from 14.0% to 2.5% (P =.006). This improved antileukemic efficacy also translated into significantly better disease-free and overall survival. A risk-adapted strategy combining anthracycline monochemotherapy and ATRA for induction and consolidation therapy of newly diagnosed APL results in improved antileukemic efficacy and a high degree of compliance.

All-trans retinoic acid and anthracycline monochemotherapy for the treatment of elderly patients with acute promyelocytic leukemia.

Therapeutic results in elderly patients with acute promyelocytic leukemia (APL) have been generally reported as less effective than for younger patients. Patients 60 years or older with APL who were enrolled in 2 successive multicenter PETHEMA studies received induction therapy with all-trans retinoic acid (ATRA) and idarubicin, consolidation with 3 anthracycline monochemotherapy courses with or without ATRA, and maintenance with ATRA and low-dose chemotherapy. Eighty-seven of 104 patients achieved complete remission (84%). Eighty-six proceeded to consolidation therapy (2 withdrew after the first and second courses). Deaths in remission occurred during consolidation and maintenance therapy in 3 and 4 patients, respectively. One patient showed molecular persistence after consolidation and 5 had a relapse. The 6-year cumulative incidence of relapse, leukemia-free survival, and disease-free survival were 8.5%, 91%, and 79%, respectively. A significantly higher incidence of low-risk patients found among the elderly, as compared to younger patients, may partially account for the low relapse rate observed. This study confirms the high antileukemic efficacy, low toxicity, and high degree of compliance of protocols using ATRA and anthracycline monochemotherapy for induction and consolidation therapy in elderly patients.