Analysis of prognostic factors in newly diagnosed patients with acute promyelocytic leukemia: the APL92 study of the Japan Adult Leukemia Study Group (JALSG)

All-trans-retinoic acid (ATRA) has been incorporated in front-line therapy for newly diagnosed acute promyelocytic leukemia (APL). We conducted a multicenter study of differentiation therapy with ATRA alone or in combination with chemotherapy followed by intensive postremission chemotherapy in patients with APL (the JALSG APL92 study), and analyzed prognostic factors to increase the cure rate in our subsequent trial. From 1992 to 1997, adult patients with newly diagnosed APL received oral ATRA 45 mg/m2 daily alone until complete remission (CR) if initial leukocyte counts were < 3.0x10(9)/l, and ATRA daily plus daunorubicin (DNR) 40 mg/m2x3 days plus enocitabine (BHAC) 200 mg/m2x5 days if leukocyte counts were > or =3.0 x 10(9)/l. If peripheral blasts exceeded 1.0x10(9)/l during therapy, DNRx3 days plus BHACx5 days was added. After CR was achieved, three courses of consolidation and six courses of maintenance/intensification chemotherapy were administered. Of 376 patients enrolled, 369 were evaluable (median age 46 years, range 15-86 years; median leukocyte counts 2.0x10(9)/l), and 333 (90%) achieved CR (94% of patients treated with ATRA alone, 88% with ATRA plus later chemotherapy, 89% with ATRA plus initial chemotherapy, and 86% with ATRA plus initial and later chemotherapy). At a median follow-up of 45 months, the predicted 6-year overall and event-free survival (EFS) rates for all patients were 65% and 52%, respectively. Favorable prognostic factors for CR were younger age, no or mild purpura, high serum total protein level, low lactate dehydrogenase level, and no or mild disseminated intravascular coagulation (DIC). Favorable prognostic factors for EFS were leukocyte counts < 10.0x10(9)/l, mild DIC, and no sepsis during induction therapy. In the JALSG APL97 study, we intensified chemotherapy for patients with leukocyte counts > or =3.0x10(9)/l, and are randomly testing whether further chemotherapy is required for APL patients with negative PCR for PML/retinoic acid receptor alpha in the maintenance phase.     

All trans retinoic acid in acute promyelocytic leukemia.

All trans retinoic acid (ATRA) is able to induce complete remission (CR) in almost all patients with acute promyelocytic leukemia (APL) through in vivo differentiation of APL blasts. However, it cannot eliminate the leukemic clone and to be effective must be used in combination with anthracycline-based chemotherapy. Experience accumulated over the last 10 years has clearly shown that the combination of ATRA and chemotherapy gives better survival in newly diagnosed APL than chemotherapy alone because of fewer relapses and a higher CR rate experienced by these patients. It is also strongly suggested that maintenance treatment with ATRA, and possibly in combination with low-dose chemotherapy, can further reduce the incidence of relapse. Overall, more than 90% of patients with newly diagnosed APL can achieve CR and about 75% can be cured by the combination of ATRA and chemotherapy.     

Long-term follow-up confirms the benefit of all-trans retinoic acid in acute promyelocytic leukemia. European APL group.

First results of a randomized trial (APL91 trial) and other randomized or non-randomized studies have shown that ATRA followed by chemotherapy significantly increased event-free survival (EFS) and survival, and decreased the incidence of relapse by comparison to chemotherapy alone in newly diagnosed APL. We present here long-term follow-up of the APL91 trial. In this trial, 101 patients had been randomized between ATRA followed by three courses of daunorubicin-AraC chemotherapy (ATRA group) and the same chemotherapy alone (chemotherapy group). Results were reanalyzed 73 months after closing of patient entry. Updated results of APL 91 trial found a Kaplan-Meier estimate of EFS and relapse rate at 4 years of 63% and 31% in the ATRA group, as compared to 17% and 78% in the chemotherapy group (P= 10(-4) and relative risk 2.95, P= 10(-4) and relative risk 3.68, respectively). Kaplan-Meier survival at 4 years was 76% in the ATRA group and 49% in the chemotherapy group (P= 0.026, relative risk 2.7). In the chemotherapy group, seven of the 27 relapses occurred after 18 months, but no relapse was seen after 43 months. In the ATRA group, four of the 17 relapses occurred after 18 months, including two late relapses (at 58 and 74 months). In the chemotherapy group, 23 of the 25 patients who relapsed achieved a second CR with ATRA, and the Kaplan-Meier estimate of second relapse was 40% at 30 months. In the ATRA group, the 10 patients who relapsed and were retreated with ATRA achieved a second CR. In conclusion, long-term results of APL91 trial confirm the superiority of the combination of ATRA and chemotherapy over chemotherapy alone in newly diagnosed APL, and that ATRA should be incorporated in the front-line treatment of APL.     

Early onset of chemotherapy can reduce the incidence of ATRA syndrome in newly diagnosed acute promyelocytic leukemia (APL) with low white blood cell counts: results from APL 93 trial.

Treatment combining ATRA and chemotherapy (CT) has improved the outcome of APL patients, by comparison with CT alone. ATRA syndrome is a life-threatening complication of ATRA treatment whose prophylaxis remains somewhat controversial. In APL93 trial, newly diagnosed APL patients CT) and ATRA with early addition of CT, on day 3 of ATRA treatment (ATRA + CT). The incidence of ATRA syndrome in the ATRA --> CT arm was 18% (22/122) as compared to 9.2% (17/184) in the ATRA + CT arm (P = 0.035). In the ATRA --> CT arm, three (2.5%) patients died from ATRA syndrome, as compared to one (0.5%) in the ATRA + CT group. Early addition of chemotherapy to ATRA in newly diagnosed APL with low WBC counts significantly reduced the incidence of ATRA syndrome.     

Treatment of Newly Diagnosed Acute Promyelocytic Leukemia (APL) by All Transretinoic Acid (ATRA) Combined with Chemotherapy: The European Experience

All transretinoic acid (ATRA) gives complete remission (CR) rates of 80 to 90% in newly diagnosed acute promyelocytic leukemia (APL). However, it has two major drawbracks (1) a rapid rise in WBC in some patients, with potentially fatal ATRA syndrome (2) rapid relapse with maintenance therapy using ATRA alone or low dose chemotherapy. The French APL group therefore designed a treatment approach with ATRA followed by intensive chemotherapy. The latter was administered after CR achievement with ATRA, or was rapidly added to ATRA in case of rapid rise in leukocyte counts. This combined approach, in a pilot study and in a randomized trial, proved superior to intensive chemotherapy alone, by slightly increasing the CR rate but more importantly by reducing the relapse rate. These results were confirmed by the Chinese, Japanese and New York groups. Our group (and other European groups) are now testing in a new randomized trial the better timing of ATRA and chemotherapy administration (ATRA followed by chemotherapy or ATRA plus chemotherapy) and the role (after an intensive consolidation) of maintenance treatment with intermittent ATRA, continuous low dose chemotherapy or both.     

Role of all-trans-retinoic acid (ATRA) in the consolidation therapy of acute promyelocytic leukaemia (APL)

The role of all-trans-retinoic acid (ATRA) in the consolidation therapy of acute promyelocytic leukaemia (APL) is undefined at present. Between 1994 and 1999, we treated 38 newly diagnosed APL patients with ATRA and chemotherapy during the induction and consolidation. ATRA was given for 28 days each during the induction and 2 cycles of consolidation therapy. Chemotherapy consisted of daunorubicin and cytarabine. No maintenance therapy was given. ATRA was well-tolerated during consolidation therapy with no cases of retinoic acid syndrome. The 5-year overall and leukaemia-free survival of study patients was 82% (95% C.I. 70-95%) and 78% (95% C.I. 65-93%), respectively. These data are comparable to the studies that used prolonged maintenance with ATRA +/- chemotherapy. The role of ATRA during consolidation therapy of APL merits further investigation as this may allow shortening the overall duration of APL treatment.     

All-transretinoic acid and chemotherapy in the treatment of acute promyelocytic leukemia

BACKGROUND: All-transretinoic acid (ATRA) and chemotherapy has improved complete remission rates and disease free survival in acute promyelocytic leukemia (APL). There is scanty data from Middle East. AIM: To determine the efficacy of ATRA and multi-agent combination chemotherapy in treatment of APL in a single Centre in Kuwait. SET-UPS AND DESIGN: Tertiary cancer centre, retrospective study. METHODS AND MATERIAL: All newly diagnosed APL patients were treated with oral ATRA 45 mg/m2 daily until complete remission (CR), intravenous daunorubicin 50 mg/m2 on days 1,3 and 5, cytosine arabinoside 100 mg/m2 12 hrly on days 1 through 10 and etoposide 100 mg/m2 on days 1 through 5. Post remission three courses of intensive consolidation chemotherapy were administered. Since October 1999, maintenance chemotherapy consisting of oral 6 mercaptopurine 9 mg/m2 daily, methotrexate 15 mg/m2 weekly and ATRA 45 mg/m2 for 2 weeks every three months was added. Complete remission rates and duration, relapse rate and toxicity were studied. RESULTS: 22 of 24 evaluable patients (91.6%) achieved CR. The median duration of remission was 13 months (range 2-55 months). Three patients (12.5%) relapsed. Two patients (8.3%) developed retinoic acid syndrome and responded to dexamethasone. Five patients (20.8%) died one each of refractory disease, during remission induction and of relapse. Two patients died while in remission. CONCLUSION: ATRA and combination chemotherapy results in high complete remission rates and low relapse rate in newly diagnosed APL. Maintenance therapy may be useful in preventing relapses.     

In vivo use of all-trans retinoic acid prior to induction chemotherapy improves complete remission rate and increases rhodamine 123 uptake in patients with de novo acute myeloid leukemia

All-trans retinoic acid (ATRA) is used in the treatment of acute promyelocytic leukemia. Because ATRA has effects (increase in apoptosis, suppression of bcl-2), it has also been used for the treatment of other French-American-British (FAB) subtypes of acute myelogenous leukemia (AML). To find out the in vivo and in vitro effects of ATRA in AML, we analyzed 37 patients with de novo AML. Twenty-seven patients received ATRA before remission-induction (RI) treatment (ATRA group). Results were compared to a control group (10 patients) that received induction without ATRA during the same time period. Bone marrow or peripheral blood samples were collected from all patients on d 0 and 4. The immunphenotype, myeloperoxidase (MPO), reaction and the efflux uptake of rhodamine 123 (Rh123) were analyzed on myeloblasts in these samples. In the myeloblasts from patients treated with ATRA, the uptake of Rh123 was increased significantly (p=0.026) from d 0 to d 4, and all other parameters remained unaltered. ATRA administration increased the complete remission (CR) rate (88%, 22/25 vs 55%, 5/9) significantly (p=0.042). Logistic regression analysis revealed that ATRA administration was the important factor in CR, among other potential factors including age, white blood count, bcl-2 expression, and the uptake and efflux of Rh123 (p=0.05). Estimated disease-free survival and overall survival were similar between these two groups (43% vs 37.5% and 51.2% vs 37.5%, respectively). In conclusion, ATRA treatment prior to RI treatment may improve the CR rate in patients with de novo AML, which seems to be related to its beneficial effect on multidrug resistance.     

全反式维甲酸联合三氧化二砷治疗初诊急性早幼粒细胞白血病的疗效及对复发率的影响分析

目的：探讨应用三氧化二砷（AS2O3）联合全反式维甲酸（ATRA）与单用ATRA对初发急性早幼粒细胞白血病（APL）诱导治疗的临床疗效及对复发率的影响。方法回顾性分析接受规律治疗的初治120例APL患者的临床资料,所有患者按治疗方法不同分为观察组和对照组,每组60例。观察组予ATRA口服联合AS2O3静脉滴注治疗,对照组仅予ATRA口服治疗,根据外周血白细胞数、肝功能以及临床症状调整药物用量,均治疗直至完全缓解（CR）。观察诱导治疗阶段CR率和早幼粒白血病基因和维甲酸受体基因融合基因（PML-RARα）转阴所需时间和不良反应,巩固化疗后3年总生存率（OS）和复发率,同时分析白细胞水平对预后的影响。结果观察组早期病死率、CR率与对照组比较差异无统计学意义（P﹥0.05）,达到CR时间少于对照组（P﹤0.05）;观察组PML-RARα转阴率和总生存率高于对照组,复发率低于对照组（P﹤0.05）;选取观察组57例患者分析白细胞水平对预后的影响,WBC≥10×109/L患者复发率、病死率、未缓解（NR）率与WBC﹤10×109/L患者比较,差异无统计学意义（P﹥0.05）,CR率与总生存率则低于WBC﹤10×109/L患者。结论 AS2O3联合ATRA治疗初发APL的疗效较好,达到CR时间缩短,预后提高,白细胞水平对APL的预后有一定影响,导致CR率与总生存率降低。     

Treatment of acute promyelocytic leukemia with all-trans retinoic acid and chemotherapy--multicenter trial of the Japan Adult Leukemia Study Group (JALSG)

We report herein the clinical results of a multicenter trial of the Japan Adult Leukemia Study Group for cases of newly diagnosed acute promyelocytic leukemia (APL) treated with all-trans retinoic acid and chemotherapy (JALSG AML-92 study). Of 196 evaluable patients, 173 (88%) achieved complete remission (CR). Multivariate analysis showed that no or minor purpura at diagnosis and age less than 30 years were favorable factors for achievement of CR. There was a significant difference in the 4-year event-free survival between the AML-92 study (54%) and both the AML-87 (32%) and AML-89 (32%) studies which consisted of intensive chemotherapy. Since prognosis in patients with APL largely depends on chemotherapy, it is important to consider more effective chemotherapy during induction and consolidation therapy.     

Cytogenetics and their prognostic value in childhood and adult acute lymphoblastic leukemia (ALL) excluding L3

Cytogenetic analysis was made at diagnosis in 174 cases of ALL (101 children less than 20 years and 73 adults), excluding Burkitt's ALL (L3). In 11 children (11 per cent) insufficient material was obtained. In the remaining 90, 50 (56 per cent) had a normal karyotype, 20 (22 per cent) a hyperdiploid karyotype, five (6 per cent) a hypodiploid karyotype, 12 (13 per cent) had a translocation (including seven cases of t(1;19)) and three had a pseudodiploid karyotype without translocation. Ninety-eight per cent of patients reached complete remission (CR). Median actuarial CR duration was not attained, was 50 months, 13 months and 11 months respectively in patients with hyperdiploid, normal, hypodiploid karyotype and in patients with a translocation, the difference between subgroups being significant. In a Cox model, cytogenetics were the strongest factor predicting CR duration (p = 0.03) followed by leukocytes (p = 0.04), whereas the presence of ‘bulky disease’ had a borderline value (p = 0.077). Of note was that 9/17 (53 per cent) patients with a hypodiploid karyotype or a translocation had no ‘risk factors’ before cytogenetic analysis. In adults, cytogenetic analysis was unsuccessful in 15 (20 per cent) of patients. In the remaining 58 cases, 19 (33 per cent) had a normal karyotype, 15 (26 per cent) had a hyperdiploid, one (2 per cent) had a hypodiploid karyotype, 19 (33 per cent) had a translocation (including 12 t(9;22)), and four (7 per cent) had a pseudodiploid without translocation. 73 per cent patients reached CR. Median actuarial DFS was 12.5 months. No significant differences in CR rate and CR duration were seen between cytogenetic groups, but median CR duration was slightly longer in patients with a normal karyotype (17 months) and shorter in patients with t(9; 22) (8.5 months). Only 3/12 of the latter had major risk factors before cytogenetic analysis. Cytogenetic analysis is important in ALL, especially in patients with otherwise standard risk factors, as it may reveal unexpected translocations or hypodiploidy, which may require a therapeutic reinforcement.     

Outcome of childhood acute promyelocytic leukemia with all-trans-retinoic acid and chemotherapy.

PURPOSE: To determine the results of treatment combining all-trans-retinoic acid (ATRA) and chemotherapy (CT) in childhood acute promyelocytic leukemia (APL). PATIENTS AND METHODS: Children (< 18 years) with newly diagnosed APL were included in the APL93 trial, treated by ATRA followed or combined with daunorubicin-cytarabine, and then randomly assigned between no maintenance, intermittent ATRA, continuous CT, or both. RESULTS: Of the 576 patients included in APL93 trial, 31 (5%) were children, including 22 girls (71%) and nine boys (29%). Thirty of the children (97%) obtained complete remission (CR). ATRA syndrome occurred in four children (13%), who all achieved CR, and headaches occurred in 12 children (39%), with signs of pseudotumor cerebri in five children (16%). Seven patients (23%) relapsed. None of the eight patients who received both ATRA and CT for maintenance relapsed. All relapsing patients achieved a second CR. Twenty-two patients remained in first CR after 43+ to 96+ months, six remained in second CR after 17+ to 66+ months, and three patients had died. The 5-year event-free survival (EFS), relapse, and overall survival rates were 71%, 27%, and 90%, respectively. No difference between adults and children included in the APL93 trial was seen for CR rate, 5-year relapse rate, EFS, and overall survival, but significantly better survival was seen in children after adjustment on WBC counts (P =.02) and incidence of microgranular M3 variant (P =.04). CONCLUSION: ATRA combined with CT for induction and also probably for maintenance provides as favorable results in children with APL as in adults and currently constitutes the reference first-line treatment in both age groups.     

PML-RARα inhibitors (ATRA, tamibaroten, arsenic troxide) for acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is characterized by generation of the PML-RARα fusion gene. PML-RARα can homodimerize with another PML-RARα, and the hybrid binds the histone-deacetylase recruiting co-repressor complex with higher affinity than the wild-type RARα. However, the co-repressor complex is releasable by pharmacological doses of all-trans retinoic acid (ATRA). More than 90% of patients with APL achieve a complete remission (CR) with differentiation therapy consisting of ATRA combined with chemotherapy. A new synthetic retinoid, tamibaroten, showed therapeutic effectiveness in patients with ATRA-resistant APL with increased expression of cellular retinoic acid binding protein (CRABP), and about 60% of patients with relapsed APL achieved a CR. Arsenic trioxide triggers the rapid degradation of PML-RARα through the targeting of the PML moieties of the fusion protein and showed a high CR rate in relapsed APL. The combination of ATRA, chemotherapy, and/or new agents improved the long-term survival in patients with APL.     

Clinical presentation,hematologic features and treatment outcome of childhood acute lymphoblastic leukemia: a review of 73 cases in Hong Kong

Seventy-three consecutive cases of childhood acute lymphoblastic leukemia (ALL) diagnosed and managed in Queen Mary Hospital over a 10-year period from 1985 to 1994 were retrospectively analysed for their presenting features and treatment outcome. The 48 boys and 25 girls ranged in age from 0·4 to 14·2 years (median: 4·3 years). Bone and joint pain was a relatively common presenting feature besides fever, hepatosplenomegaly and lymphadenopathy. Immunophenotyping of blast cells showed: 51 B-cell precursor ALL, one B-ALL, 10 T-ALL and three myeloid-antigen positive ALL. Eight cases were unclassified since immunophenotyping had not been performed. Out of the 73 patients, treatment outcome was analysed in 20 cases treated with UKALL-VIII regimen and 28 cases treated with either the UKALL-XI regimen or the Hong Kong Children Cancer Study Group (HKCCSG) protocol which was modelled upon UKALL-XI. Although complete remission rates were similar between the two groups, patients treated with the former regimen that was less intensified suffered more relapses than the latter (56 per cent versus 21 per cent, P=0·04). There were, however, no significant differences both in event-free survival (38·2±11·2 per cent versus 71·3±9·3 per cent, P=0·12) and overall survival (70·0±10·2 per cent versus 79·6±8·3 per cent, P=0·41) between the two groups at 3 years by log-rank test. With the use of risk-directed therapy and improved supportive care, two-thirds of our patients are able to enjoy long-term event-free survival. © 1997 John Wiley & Sons, Ltd.     

Clinical experience with a new synthetic retinoid, tamibarotene (Am-80) for relapsed or refractory acute promyelocytic leukemia

A new synthetic retinoid, Am-80 is expected to overcome all-trans retinoic acid (ATRA) resistance, because of several times more potent differentiation activity than ATRA and sustained plasma level during continuous administration due to a lower affinity for cellular retinoic acid binding protein. In a preliminary study in Japan, 14 (58%) of 24 acute promyelocytic leukemia (APL) patients who had relapsed from ATRA induced complete remission (CR) achieved a second CR. Of these 14 CR patients, 4 of 6 who underwent allogeneic stem cell transplantation (SCT) are alive, and 4 of 8 patients who received only chemotherapy are alive without relapse for >4 years. Adverse events include xerosis, cheilitis, hyperlipidemia and so on, but these were generally milder than ATRA. In a phase 2 clinical trial, 25 (61%) of 41 patients entered CR. Among 23 first relapsed patients, 18 (78.3%) patients entered CR, indicating excellent salvage effects for ATRA-relapsed patients. Am-80 may improve disease free survival when used as remission induction and/or maintenance therapy, and it may be effective for relapse from ATRA-induced remission and be curative for patients who receive SCT or intensive post remission chemotherapy.     

Hematological features and treatment outcome in acute myeloid leukemia with t(8;21)

We analyzed the hematological features and treatment outcome in 18 patients with t(8;21) acute myeloid leukemia (AML) diagnosed in Queen Mary Hospital, Hong Kong. They comprised 15 cases of M2, two cases of M4 and one case of M1 according to FAB criteria. Auer rods (17 cases) and dysgranulopoietic features (15 cases) were very frequently observed. Two cases showed marrow eosinophilia while blast cells in one patient demonstrated erythrophagocytic activity. Chromosome changes in addition to t(8;21) were seen in 14 patients, the most common of which was loss of a sex chromosome (10 cases). Of the 14 patients treated with intensive chemotherapy, 13 (93 per cent) entered complete remission with a median event-free survival (EFS) and overall survival (OS) of 11 and 24 months respectively. The probability of EFS and OS at 3 years were 33±14·3 per cent and 55·1±15·6 per cent respectively with a median duration of follow-up of 22 months. When compared with AML having no t(8;21) treated similarly in the same period, we could not demonstrate a better clinical outcome for t(8;21) AML. © 1997 John Wiley & Sons, Ltd.     

Treatment of acute promyelocytic leukemia: strategy toward further increase of cure rate.

Acute promyelocytic leukemia (APL) has become a curable disease by all-trans retinoic acid (ATRA)-based induction therapy followed by two or three courses of consolidation chemotherapy. Currently around 90% of newly diagnosed patients with APL achieve complete remission (CR) and over 70% of patients are curable. To further increase the CR and cure rates, detection and diagnosis of this disease at its early stage is very important, hopefully before the appearance of APL-associated coagulopathy. In induction therapy, concomitant chemotherapy is indispensable, except for patients with low initial leukocyte counts. Prophylactic use of intrathecal methotrexate and cytarabine should be done, particularly for patients with hyperleukocytosis. If patients relapse hematologically or even molecularly, arsenic trioxide will be the treatment of choice under careful electrocardiogram monitoring. Am80, liposomal ATRA, gemtuzumab ozogamicin or ATRA in combination with cytotoxic drugs may be used at this stage or later. Allogeneic SCT will be the treatment of choice after patients of age <50 years have relapsed, provided that they have HLA-identical family donors or DNA-identical unrelated donors.     

全反式维甲酸联合三氧化二砷治疗儿童急性早幼粒细胞白血病疗效观察

 目的　观察全反式维甲酸（ ATRA ）联合三氧化二砷（ As2O3）治疗儿童初发急性早幼粒细胞白血病（ APL）的疗效和不良反应。方法　ATRA 联合As2O3治疗初发 APL患儿16例。治疗方案：ATRA 25 mg·m-2·d-1，分2～3次口服，As2O3 0.16 mg·kg-1·d-1，加入生理盐水或50 g／L葡萄糖溶液静脉滴注，持续 4～6 h，1次／d。结果　14 例患者获得完全缓解（CR），CR率87.5 ％，CR时间短，没有明显不良反应。结论　ATRA联合As2O3治疗儿童APL能获得很好疗效。     

三氧化二砷治疗初治急性早幼粒细胞白血病疗效分析

 目的　分析以三氧化二砷（ATO）为基础的诱导和维持治疗方案治疗初发急性早幼粒细胞白血病（APL）的长期疗效。方法　回顾性分析62例初诊成年APL患者诱导缓解治疗和缓解后巩固维持治疗经过,并作5、7年随访分析。结果　诱导治疗阶段,ATO+全反式维甲酸（ATRA）双药联合化疗组与ATRA联合化疗组完全缓解（CR）率差异无统计学意义,但前者达到CR时间明显缩短。诱导治疗后PML-RARα融合基因转阴率两组分别为86.2 %、56.3 %,差异有统计学意义（P＜0.05）。巩固维持治疗阶段,ATO序贯维持组和化疗序贯维持组5年总生存（OS）率分别为（94.4±5.4）%和（45.5±10.2）%,7年OS率分别为（52.5±23.7）%和（27.3±9.3）%;两组5年无病生存（DFS）率分别为（94.7±5.5）%和（41.3±10.1）%,7年DFS率分别为（52.6±23.7）%和（27.5±9.4）%,两组差异有统计学意义（P＜0.05）。并且,ATO序贯维持组复发率（14.7 %）低于化疗序贯维持组（37.0 %）,差异有统计学意义（P＜0.05）。结论　以ATO联合ATRA、化疗的诱导化疗方案可缩短诱导化疗时间,提高PML-RARα融合基因转阴率,而且,包含ATO的序贯维持治疗明显改善APL患者的长期生存,减少复发,安全性高,患者耐受性好。