LPA99 Trial Research Articles

High Post-Remission WT1 Expression Is a Predictive Marker for Subsequent Molecular Relapse and Poor Survival Outcome in Adult Patients with Acute Promyelocytic Leukemia (APL)

Background: Acute promyelocytic leukemia (APL) is classified into favorable-risk group and long-term overall survival (OS) is estimated at around 80%. Relapse rate of APL is relatively lower than another acute myeloid leukemia (AML) subtypes, but we still confront relapse in 10-20% and some relapsed cases are hardly cured even after hematopoietic cell transplantation (HCT). Therefore, it is important to find out patients with high-risk of relapse and early intervention should be considered. In APL, PML-RARa RQ PCR is used as a marker for residual disease, but the marker is not useful for pre-emptive management for relapse prevention because its positivity directly indicates relapse of disease. WT1 expression is a well-known marker in AML, and the expression is higher in APL than the other AML subtypes (Cilloni et al., leukemia, 2002). We monitored WT1 decrement along the treatment courses to identify its significant role as a marker for relapse prediction.Methods: In this study, 117 APL patients with a median follow-up duration of 38.5 months (range, 9.7-81.3) from 2008 to 2014 were analyzed. APL was diagnosed by RT-PCR method for detection of PML-RARa and all patients were available with cytogenetic results. All except 5 with normal karyotype was identified with t(15;17)(q22;q21) and 33 (28.2%) showed combination of additional chromosomal abnormalities. Our treatment protocol was based on LPA99 trial using ATRA and idarubicin monotherapy (Sanz et al., Blood, 2004). In relapsed patients, we applied ATO and some high-risk patients were treated with HCT (n=3). PML-RARa and WT1 expression in the BM samples were quantified by RQ-PCR method, and we used WT1 ProfileQuant¢â kit (Ipsogen) for WT1 monitoring. We measured RQ-PCR levels at diagnosis, post-induction and each of the 3 post-consolidation chemotherapies, and 3 months interval after starting maintenance therapy. FLT3- ITD/TKD mutation was evaluated by multiplex allele-specific PCR and concomitantly analyzed. Significant cut-off level of PML-RARa and WT1 expression was calculated by ROC curve analysis. According to the level, we calculated OS, disease free survival (DFS), and cumulative incidence of relapse (CIR).Results: Hematological complete remission (CR) was identified in 117 (100.0%) patients but complete molecular remission (CMR) was identified in 68 (42.7%) after induction. Among 49 patients who failed to achieve CMR, 44 patients achieved CMR after 1st consolidation and 5 patients after 2nd consolidation. Three-year OS and EFS was 92.5% and 82.0%, and CIR rate was 14.7% (n=13). Three patients showed clonal evolution to therapy-related AML and 1 patient died in CR due to lung cancer. FLT3 -TKD and FLT3 -ITD mutation was identified in 6 (5.1%) and 25 (21.4%) patients, and PML-RARa BCR3 and BCR1 subtype was identified in 32 (27.4%) and 85 (72.6%) patients, respectively. For relapse prediction, we analyzed WT1 expression at several time points in association with CMR after induction, FLT3 -ITD/TKD mutation, BCR subtype, and hyperleukocytosis at diagnosis and during first chemotherapy. High WT1 expression (>120 copies/104ABL1) in early period (3 months) after maintenance therapy significantly predicted subsequent relapse. All paired PML-RARa RQ-PCR was not detected except one sample with early relapse after 3rd consolidation. Patients with high post-maintenance WT1 expression (n=40) showed significantly higher CIR rate (30.7% vs. 4.2%, p=0.0003) and inferior 3-year OS (86.1% vs. 97.9%, p =.0103) and DFS (62.8% vs. 94.1%, p<.0001). Multivariate analysis revealed high leukocyte counts [HR=9.2, 95%CI=2.2-38.5, p =.002], WT1 at 3 months post-maintenance [HR=8.7, 95%CI=1.9-38.9, p =.0051], and FLT3 mutation [HR=5.4, 95%CI=1.5-19.4, p =.0092] were significant factors for relapse prediction. However, even in the BCR3 or FLT3 -positive subgroup (n=48), low WT1 at post-maintenance 3 months was associated with lower CIR rate (13.4% vs. 50.8%, p<.0001) and better DFS (95.2% vs. 49.2%, p<.0001).Conclusion: High post-remission WT1 expression was a reliable marker for the prediction of subsequent relapse in APL, even when PML-RARa was not detected at 3 months post-maintenance. In this high-risk group, early intervention with ATRA±ATO, WT1 vaccination or WT1 -specific cytotoxic cell therapy may be used for relapse prevention. The role of WT1 expression needs to be validated by prospective studies in a large cohort. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Results with ATRA and Anthracycline Based Chemotherapy (CT) in Acute Promyelocytic Leukemia (APL) in a Developing Country. Should Dose Intensity Be Reduced to Obtain Acceptable Results?

Abstract 4271 Background:In Tunisia, before 1998, ATRA was not available in APL, and we reported CR rates of 37.5% (unpublished results). The ATRA era began in 1998 with the consecutive use of two regimens combining ATRA and an anthracycline with AraC (APL93 trial), and without AraC (LPA99 trial). We report outcome of those clinical trials in our country, whose yearly GDP is about 8000 USD/inhabitant (ranking n°55 in the world). Methods:Between 1998 and 2010, consecutive patients with genetically confirmed APL were treated, until 2004 (n= 27 patients, median age, 27 years) with the European APL93 trial induction treatment with ATRA 45 mg/m2 from day (D)1 and DNR (60mg/m2/d x3)+ AraC (200mg/m2/d x7) started from D1 if WBC ≥ 5G/L and D3 if WBC < 5G/L.Patients achieving CR received a first consolidation course with the same CT and a second with DNR at 45 mg/m2/dx3 and AraC 1g/m2/12h x8. Maintenance treatment consisted of a combination of ATRA 45 mg/m2 for 15 days every 3 months,6MP at 50 mg/m2/d and MTX 15mg/m2/week (Adès L.Blood 2010;115:1690). Between 2004 and 2010, 51 patients (median age,30 years) received the Spanish PETHEMA LPA 99 protocol (Induction with ATRA 45 mg/m2/day and idarubicin 12 mg/m2 on days 2, 4, 6, 8); 2 risk-adapted consolidation courses with IDA, with ATRA (only for Int- and high-risk patients) and for all patients one consolidation course with mitoxantrone 10mg/m2 for 5 days, followed by the same maintenance therapy as in the European APL trial. (Sanz MA, Blood 2008;112:3130). During induction therapy coagulopathy was treated with fresh-frozen plasma(FFP) and apheresis platelets with the objective of maintaining platelet counts above 30G/L, prothrombin time >50% and, fibrinogen >1 g/L. Heparin was not used. During maintenance treatment, all patients were monitored clinically every month and molecularly for PML-RARA every 3–4 months. Results:The two patient cohorts were comparable except for the incidence of M3v (1/27 in APL93 vs. 12/51 in LPA 99,P=0.023).34.6% (27/78) of patients were HR Sanz' score.With the European trial (26 patients treated, one patient died before treatment), the CR rate was 77%, while 23 % patients (6/26) had early death: 4 from hemorrhage and 2 from DS (overall incidence of DS: 15%).4 year event free survival (EFS), cumulative incidence of relapse (CIR) and overall survival (OS) was 61.5%, 14.2%, 65% respectively. In high risk patients (n=9), 5 achieved CR,2 relapsed, and 3 were long term survivors. With LPA 99 trial, 43 (86%) pts achieved CR. The remaining 7 (14%) pts had early death (one died before treatment onset): 4 from DS (overall incidence of DS: 32%) and 3 from CNS hemorrhage. 2 pts relapsed at 35 and 36 months of CR. 2 pts developed secondary MDS and 2 died in CR,from sepsis during the third consolidation course and one from cardiac failure after 15 months of CR, respectively. With a median follow-up of 50 months, 5 year CIR, EFS and OS were 4.7%, 74% and 78%, respectively. In high risk patients (n=18), the CR rate,5 year CIR, EFS and OS were 70.5 %,0%,64.7 %,64.7%, respectively.The only prognostic factor of death during induction for the whole study population was high baseline WBC > 10G/L (P=0.003). Male gender (P=0.77), M3v (P=0.23),CD56 positivity (P=0.49), and WBC > 10G/L (P=0.71) were not predictive of relapse.Median transfusion requirement during induction treatment was: 8 PRBC in APL93 trial (range, 3–18) and 4 in LPA 99 trial (range, 3–11); 6 apheresis platelet concentrates in APL 93 trial (range, 3–11) and 4 in LPA 99 trial (range, 1–16); 11 FFP concentrates (range, 0–53) and 7 (range, 0–36), respectively. Conclusion:Despite more limited resources than in industrialized countries, and non availability of arsenic derivatives, our results are quite acceptable. The CR rate we observed is still inferior to what is reported in international trials but, our results improved over time especially with the less myelosuppressive Spanish trial, including in patients with WBC > 10 G/l. Our results suggest that there is probably no need to adapt protocols by reducing dose-intensity in APL trials in developing countries, at least if an adequate transfusion program and adequate management of DS can be implemented during induction treatment. Disclosures:Fenaux:Celgene: Honoraria, Research Funding.

Risk-Adapted Treatment for Low- and Intermediate-Risk Acute Promyelocytic Leukemia

The clinical integration of risk-tailored therapies for patients with acute promyelocytic leukemia (APL) has become a standard treatment approach in recent years. In this article, we will review the risk-adapted strategies designed to treat patients with white blood cell counts ≤ 10 × 109/L, with platelet counts > 40 × 109/L (low risk), or platelet counts ≤ 40 × 109/L (intermediate risk), with particular reference to the risk-adapted strategy followed in the LPA99 and LPA2005 trials conducted by the Programa para el Tratamiento de Hemopatías Malignas group. In these studies, the combination of all-trans-retinoic acid (ATRA) and chemotherapy in consolidation therapy resulted in an improved antileukemic efficacy without significantly increasing toxicity in low-risk (LPA2005 trial vs. LPA99 trial) and intermediate-risk (LPA99 trial vs. LPA96 trial) categories. In addition, a decrease in dose intensity of mitoxantrone in low- and intermediate-risk patients (LPA2005 trial vs. LPA99) resulted in a significant reduction of hematologic toxicities and hospital stay without compromising antileukemic activity. We will also discuss whether the use of arsenic trioxide to reinforce consolidation therapy in standard ATRA/chemotherapy regimens can permit a reduction of chemotherapy intensity while maintaining cure rates or confirm the improvement on outcomes currently achieved with optimal ATRA/anthracycline-based protocols.

Impact of additional chromosomal abnormalities in patients with acute promyelocytic leukemia: 10-year results of the Japan Adult Leukemia Study Group APL97 study

Impact of additional chromosomal abnormalities in patients with acute promyelocytic leukemia: 10-year results of the Japan Adult Leukemia Study Group APL97 study

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

AbstractA 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 × 109/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.

Treatment of Newly Diagnosed Acute Promyelocytic Leukemia (APL) in the Elderly: A Joint Analysis of the French -Belgian-Swiss and PETHEMA Groups.

Abstract 845 Background:ATRA combined to anthracycline-based chemotherapy (CT) for induction and consolidation followed by prolonged maintenance is a standard treatment of newly diagnosed APL, but the outcome and prognostic factors in the elderly are less well established than in younger patients (pts). Methods:We performed a joint analysis of elderly pts included in two subsequent trials of the PETHEMA group (LPA96 and LPA99) and and on the French -Belgian-Swiss APL group (APL93 and APL2000). In the PETHEMA trials, pts received induction therapy with ATRA and idarubicin (Ida 12 mg/m2/d, d2,4,6,8), consolidation with 3 anthracycline monochemotherapy courses (2 with Ida and 1 with mitoxantrone, with ATRA and higher idarubicin dose for Sanz's int and high risk pts in LPA99 trial), and 2-year maintenance with intermittent ATRA and continuous low-dose CT (6MP + MTX). In APL 93 and 2000 trials: pts received induction therapy with ATRA and DNR (60mg/m2/d ×3d)+AraC, (200 mg/m2/d×7) followed by consolidation with a similar course and a final DNR (45 mg/m2/d × 3) + AraC (1-2 g/m2/12h × 8) course (omitted in pts >65y) and the same maintenance as in PETHEMA trials. Median follow up was 75 and 42 months in PETHEMA and APL trials, respectively. Results:1575 consecutive newly diagnosed APL pts were enrolled in the 4 trials, including 1288 (81%), 105 (6.6%), 91 (5.7%) and 91 (5.7%) aged <60, 60-65, 65-70, and >70, respectively (ie 287 pts (18%) older than 60). CR rates in these age groups were 94.6%, 84.8%, 81.8% and 78.4% (p=0.0002). All failures were due to early death, except one due to resistant leukemia, in a younger adult. The 5-year cumulative incidence of relapse was 16.5%, 19.1% ,11.9% and 13.5% in pts <60, 60-65, 65-70 and >70, respectively (p= 0.63). The 5-year OS in these age groups was 85.8%, 68.7%, 63.8% and 56.4% (p<0.0001). The 5-year rate of death in CR , mainly resulting from myelosuppression during post induction treatment, increased with age, from 3.1%, 11.8%, 14.6% up to 17.9% in patients <60, 60-65, 65-70 and >70 years, respectively (p<0.0001). By multivariate analysis stratified on the trial (APL and LPA), better OS was associated with age <60 (HR 2.645, p<0.0001), female gender (HR 0.77, p=0.05), lower WBC (HR 1.007, p<0.0001) and higher platelets (HR 0.996, p=0.03).In pts >60 yrs, by multivariate analysis, early death was associated with increased WBC (p=0.046), and increased creatinine level (p=0.002). Higher CIR was associated with increased WBC (p=0.002) . In patients older than 60 years, age had no significant impact on CR rate and survival. Finally, no significant differences in outcome were seen between French Belgian Swiss and PETHEMA trials. Conclusion:In pts older than 60, classical APL treatment with ATRA combined to anthracycline based CT followed by prolonged maintenance gives no initial leukemic resistance and similar relapse rate as in younger pts, but significantly lower OS due to a higher incidence of early deaths and of deaths in CR compared with younger pts. Higher WBC counts are associated with an increased incidence of both early deaths and deaths in CR. Improvement in prognosis, therefore, requires better supportive care during induction treatment, while reduction of the amount of myelosuppressive drugs during post induction treatment may be required to reduce deaths in CR. Disclosures:Fenaux:CELGENE: Research Funding; AMGEN: Research Funding.

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

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. 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. 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. 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.

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

AbstractDifferentiation 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 × 109/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: Results of the PETHEMA LPA2005 Trial Using All-Trans Retinoic Acid and Anthracycline with Cytarabine for High-Risk Patients

Background: A previous report of the PETHEMA Group (Sanz et al, Blood 2004) showed that a risk-adapted strategy combining ATRA and anthracycline monochemotherapy for induction and consolidation (LPA99 trial), followed by ATRA and low dose methotrexate and mercaptopurine for maintenance therapy, resulted in high antileukemic efficacy, moderate toxicity, and a high degree of compliance. A critical analysis of this study led us to consider the following opportunities for improvement in a new trial:the observation of a lack of relapses in non high-risk patients (WBC counts <10 × 109/L) who had received incomplete consolidation therapy due to the occurrence of severe complications, led us to consider that there was room for a reduction of chemotherapy in this potentially overtreated setting;the outstanding results reported by the Italian GIMEMA Group in high-risk patients < 60 years combining ATRA, anthracycline and cytarabine in consolidation (Lo- Coco et al, ASH 2004) led us to investigate a similar strategy looking for a synergistic effect of this triple combination of drugs.Thus, a new risk-adapted PETHEMA trial (LPA 2005) was designed and initiated in July 2005.Methods: AIDA regimen (ATRA 45 mg/m2/d ATRA until CR and idarubicin 12 mg/m2/d on days 2, 4, 6 and 8) was given as induction therapy. Patients in CR received 3 monthly courses of risk-adapted consolidation therapy as follows: i.”low-risk” patients (WBC <10×109/l and platelets >40×109/l) received ATRA (45 mg/m2/d × 15) simultaneously with idarubicin 5 mg/m2/d × 4 (course #1), mitoxantrone 10 mg/m2/d × 3 (course #2), and idarubicin 12 mg/m2/d × 1 (course #3); ii.”intermediaterisk” patients (WBC <10×109/l and platelet <40×109/l) received ATRA (45 mg/m2/d × 15) in combination with reinforced chemotherapy (idarubicin 7 mg/m2/d in the course #1 and 2 days instead of 1 in the course #3). Both risk groups received mitoxantrone × 3 in course #2 instead of × 5 in the LPA99 trial; and iii.”high-risk” patients (WBC >10×109/l) < 60 years received ATRA (45 mg/m2/d × 15) and idarubicin in courses #1 and #3 at the same dose than for low-risk patients but with the addition of cytarabine (1000 mg/m2/d × 4 in course #1 and 150 mg/m2/8 h days 1 to 4 in course #3) and 2 more days of mitoxantrone in course #2 (5 days instead of 3). Maintenance therapy consisted of 50 mg/m2/d mercaptopurine orally, 15 mg/m2/week methotrexate intramuscularly, and 25 mg/m2/d ATRA for 15 days every three months during 2 years.Results: Of 319 patients enrolled in the LPA 2005 trial between July 2005 and July 2008, data on baseline characteristics and induction outcome was available from 290 patients. CR was achieved in 268 patients (92%). No resistant cases were observed. Toxicity was manageable during consolidation and there were 2 deaths in CR during consolidation. The median follow-up of the cohort was 21 months (range, 2–38). Six patients presented hematological relapse and 3 molecular relapse. Overall, the 2-year cumulative incidence of relapse (CIR), disease-free survival, and overall survival were 5%, 94%, and 92%, respectively. The 2-year CIR for low-, intermediate- and high-risk patients were 0%, 6% and 8%, respectively. A comparison of these results with those obtained with the LPA99 trial show a statistically significant lower CIR in high-risk patients (p=0.047).Conclusions: The significant improvement of the outcome observed in high-risk patients suggests a synergistic effect of the triple combination of ATRA, anthracycline and cytarabine.

Incidence, Outcome and Risk Factors of Pseudotumor Cerebri after All- Trans Retinoic Acid and Anthracycline-Based Chemotherapy in Patients with Acute Promyelocytic Leukemia

Background: Pseudotumor cerebri associated with all-trans-retinoic acid (ATRA) treatment in acute promyelocytic leukemia (APL) have been frequently described in pediatric patients. However, the incidence, outcome and risk factors of pseudotumor cerebri in APL are not well-known. We analyze the incidence and risk factors of this complication in a large series of patients with newly diagnosed APL enrolled in three consecutive trials of the PETHEMA Group (LPA96, LPA99 and LPA2005).Mehods: AIDA regimen (ATRA 45 mg/m2/d [25mg/m2/d in patients younger than 20] until CR and idarubicin 12 mg/m2/d on days 2, 4, 6 and 8) was given as induction therapy. Patients in CR received 3 monthly courses of risk-adapted consolidation therapy: idarubicin 5 mg/m2/d × 4 (course #1), mitoxantrone 10 mg/m2/d × 5 (course #2), and idarubicin 12 mg/m2/d × 1 (course #3). Since November 1999 (LPA99 trial), for patients with intermediate or high risk of relapse (Sanz et al, Blood 2000), consolidation was slightly intensified by increasing idarubicin doses in courses #1 and #3, and by simultaneously administering 25 mg/m2 ATRA together with chemotherapy in all three courses. Since July 2005, consolidation therapy in the ongoing LPA 2005 trial included the following modifications:the administration of ATRA for all patients;for low- and intermediate-risk patients, mitoxantrone has been reduced from five to three days in the second course; andfor high-risk patients, cytarabine has been added to idarubicin in the first and third course.Maintenance therapy consisted of 50 mg/m2/d mercaptopurine orally, 15 mg/m2/week methotrexate intramuscularly, and 25 mg/m2/d ATRA for 15 days every three months. Diagnosis of pseudotumor cerebri was made in the presence of signs and symptoms of intracranial hypertension without clinical or radiological evidence of infective or space occupying lesions.Results: Of 1034 patients enrolled between November 1996 and July 2008, 32 (3%) experienced pseudotumor cerebri. Headaches without pseudotumor were present in 252 patients (25%). Thirty cases of pseudotumor occurred during induction therapy and 2 cases manifested only during consolidation. In all, 9 of 32 patients (28%) had recurrent pseudotumor cerebri after reinitiating ATRA. All these side effects were transient, reversible, and never a cause of death. CR rates were 96% and 90% in patients with and without pseudotumor cerebri, respectively (p=0.32). The incidence of pseudotumor cerebri among patients younger than 18 years, 18–25 years, 25–50 years and older than 50 years was 13%, 7%, 2% and 0.3%, respectively (p<0.0001). There was a trend toward a correlation between fibrinogen <170 mg/dL and worse general state (ECOG>1) at presentation and development of pseudotumor cerebri (p=0.08 and p=0.06, respectively). We did not found any significant association between pseudotumor cerebri and WBC, platelets, relapse risk-score, hemoglobin, creatinine, PETHEMA trial, gender, morphological subtype, PML/RARA isoform, FLT3 mutations, and surface antigens (CD2, CD11b, CD13, CD15, CD34, CD56, and CD117).Conclusion: This study shows an overall incidence of pseudotumor cerebri of 3% among APL patients treated with ATRA and anthracycline-based regimens, with higher incidences in children and young adults (13% and 7%, respectively). No other prognostic factors could be demonstrated. The development of pseudotumor cerebri was not associated with a worse induction outcome. Side effects were reversible and transient, but roughly a third of patients had recurrent pseudotumor cerebri after reinitiating ATRA

Treatment with All-Trans Retinoic Acid and Anthracycline Monochemotherapy in Children with Acute Promyelocytic Leukemia: Analysis of Three Sequential Multicenter Trials of the PETHEMA Group

The combination of all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy has been adopted as the standard treatment for children and adults with acute promyelocytic leukemia (APL). However, information about therapy results in pediatric APL patients is scarce, particularly on long-term outcomes. A previous report of the PETHEMA Group (Ortega et al, JCO 2005) showed that a risk-adapted strategy combining a reduced dose of ATRA (25 mg/m2/d) and anthracycline monochemotherapy for induction and consolidation, followed by ATRA and low dose methotrexate and mercaptopurine for maintenance therapy, produced high antileukemic efficacy, moderate toxicity, and a high degree of compliance. We have now performed an updated analysis of a significantly enlarged cohort of 107 consecutive children (younger than 19 years) with APL who were enrolled in three sequential trials of the PETHEMA Group (LPA96, LPA99 and LPA2005) and followed up for a median of 71 months (range, 3–139). Induction consisted of 25 mg/m2 ATRA daily until CR and 12 mg/m2 idarubicin on days 2, 4, 6 and 8. In the LPA96 trial, patients in CR received three monthly chemotherapy courses: idarubicin 5 mg/m2/d × 4 (course #1), mitoxantrone 10 mg/m2/d × 5 (course #2), and idarubicin 12 mg/m2/d × 1 (course #3). Since November 1999 (LPA99 trial), for patients with intermediate or high risk of relapse (Sanz et al, Blood 2000), consolidation was slightly intensified by increasing idarubicin doses in courses #1 and #3, and by simultaneously administering 25 mg/m2 ATRA together with chemotherapy in all three courses. Since July 2005, consolidation therapy in the ongoing LPA 2005 trial included the following modifications:the administration of ATRA for all patients;for low- and intermediate-risk patients, mitoxantrone has been reduced from five to three days in the second course; andfor high-risk patients, cytarabine has been added to idarubicin in the first and third course.Maintenance therapy consisted of 50 mg/m2/d mercaptopurine orally, 15 mg/m2/week methotrexate intramuscularly, and 25 mg/m2/d ATRA for 15 days every three months. Of 1031 patients enrolled in three subsequent PETHEMA trials between November 1996 and July 2008, 107 (10%) from 43 Institutions were aged less than 19 years. WBC counts were >10×09/l and >50×109/l in 36 (34%) and 10 (9%), respectively; morphologically, 22 (22%) cases were hypergranular; PML/RARA isoform type was BCR1 or BCR2 in 47 (57%), and BCR3 in 35 (43%). One-hundred and one patients achieved CR (94%). In general, toxicity was manageable during consolidation and maintenance therapy. One patient died in CR during consolidation due to hepatic failure. At the end of consolidation, only 2 patients of 86 patients tested had molecular persistence (defined by positive RT-PCR of PML/RARA at 10−4 sensitivity). Ten additional relapses were observed, 5 molecular and 5 clinical relapses. Apart from 2 clinical relapses and 2 molecular relapses, all these events occurred among high risk patients. The 5-year Kaplan-Meier estimates of overall, disease-free and relapse-free survival were 89%, 86% and 86%, respectively. These results show a higher incidence of hyperleucocytosis in pediatric patients than in adults with genetically proven APL (p=0.05) and confirm the high antileukemic efficacy, low toxicity and high degree of compliance of three subsequent PETHEMA trials using a risk-adapted strategy with ATRA and anthracycline-based chemotherapy for induction and consolidation therapy.

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

AbstractA 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.

Predictive factors of all-trans-retinoic acid related complications during induction therapy for acute promyelocytic leukemia

Background: The combination of all-trans-retinoic acid (ATRA) and chemotherapy has made acute promyelocytic leukemia (APL) a highly curable leukemia. However, several complications are reported with this treatment the most serious and life threatening being Retinoic Acid Syndrome (RAS). We aimed at identifying factors that could predict complications caused by ATRA during induction treatment of APL.Patients: Forty-two patients with confirmed APL (by t(15;17) and/or PML/RARA) treated at our institution (University hospital of Tunis) between January 1998 and June 2006 using two consecutive protocols: European APL93 trial (24 patients) until February 2004 and Spanish PETHEMA LPA99 trial (18 patients) more recently. Induction regimen consisted of ATRA 45 mg/m2/d until CR combined to DNR 60 mg/m2/d×3+Cytarabine 200 mg/m2/d×7 (APL93) and Idarubicin 12 mg/m2 d2, 4, 6, 8 (LPA99). Prednisone (0·5 mg/kg d1–d15) was added if WBC >10×109/L to prevent RAS in LPA 99.Results: Median age was 36 yr (7–64 yr), M/F=16/26 (0·61), median WBC was 2·4×109/L (range 0·6–100×109/L). WBC >10×109/L was noted in 14 patients (33%). Additional cytogenetic abnormalities were seen in 12/42 (28%). Median body mass index (BMI=weight/height2:N 20–25) was 24 kg/m2 (range 16–40 kg/m2), BMI >30 was noted in nine patients (8F and 1M). Thirty-three patients achieved CR (78·57%):18/24 (75%) in APL93 versus 15/18 (83%) in LPA99. Nine patients (21·42%) had early death. Causes of early death were: RAS (6) and CNS hemorrhage (3). Complications due to ATRA were: RAS (10), Scrotal ulcerations (3), Sweet syndrome (2), Perineal ulcerations (1), and Pseudotumor cerebri (1). Prognostic factors for complications of ATRA (Fisher exact test) were: BMI >35 (p=0·055), induction treatment without cytarabine (LPA99 trial) (p=0·047), whereas age (p=0·74), gender (p=0·51), initial WBC (p=0·47), and additional cytogenetic abnormalities (p=0·83) were not predictive. Retinoic Acid Syndrome was more reported in patients with initial WBC >10×109/L (p=0·08).Conclusion: We found high BMI (>35) in female and treatment without Cytarabine to increase the risk of developing complications with ATRA.

Secondary Acute Myeloid Leukemia and Myelodysplastic Syndromes Following ATRA and Anthracycline Monochemotherapy Treatment for Acute Promyelocytic Leukemia.

Background: With the improved survival of patients with acute promyelocytic leukemia (APL) treated with all trans retinoic acid (ATRA) combined to anthracycline chemotherapy, acquired therapy-related myelodysplasia (tMDS), acute myelogenous leukaemia (tAML), or both, can be an emerging problem.Objectives: Analyze the incidence and characteristics of tMDS/tAML in 740 patients with newly diagnosed APL enrolled in the PETHEMA LPA96 and LPA99 trials.Methods: From 1996 to 2005, 740 patients (median age 40 years, range 2–83) were included in the LPA96 and LPA99 trials (176 and 564 patients, respectively). Induction therapy consisted of ATRA and idarubicin, followed by three consolidation courses of anthracycline monochemotherapy with or without ATRA. Maintenance therapy consisted of low-dose oral chemotherapy (mercaptopurine and methotrexate with ATRA). We measured the cumulative incidence (CI) of tMDS/tAML during the course of APL patients who achieved the complete remission (CR).Results: CR was achieved in 667 patients (90%). The median follow-up of the cohort was 66 months (range 20–127 months). Overall, 12 patients presented a tMDS/tAML, after a median of 43 months (range 23–55) from the achievement of CR. Six patients were diagnosed of tAML and 6 were diagnosed of tMDS. In all patients, RT-PCR monitoring and/or cytogenetic analysis indicated first complete remission of APL at the time of diagnosis of tMDS/tAML. Cytogenetic characterization revealed −5/del(5q) and/or −7/del(7q) abnormalities in 7 of 12 patients, whereas 11q23 rearrangements were observed in 2 patients. In spite of intensive chemotherapy (with allogeneic stem-cell transplantation in 3 patients), the course of tAML was aggressive (5 of 6 patients dead after a median of 7 months from diagnosis). Five patients with tMDS received only supportive treatment, and the remaining patient received chemotherapy and allogeneic stem-cell transplantation. Survival was also poor, with 4 patients dead after a median of 6 months, and 2 patients alive after 3 and 5 months from tMDS diagnosis. The median age at diagnosis of tMDS/tAML was 58 years (range 29–68). Four and 8 patients followed the LPA96 and the LPA99 trial, respectively. At the initial diagnosis, APL were classified, according to the Sanz score, as high-, intermediate- and low-risk, in 0, 7, and 5 patients, respectively. The overall 5 year CI of tMDS/tAML was 2.1%. The 5 year CI of tMDS/tAML in high-, intermediate- and low-risk patients was 0%, 2.2% and 4.2%, respectively (low- vs high-risk log-rank test; p=0.06). The 5 year CI of tMDS/tAML in patients <50 years and ≥50 years was 1% and 4.6%, respectively (p=0.009).Conclusion: In this large series of APL patients treated with ATRA and anthracycline monochemotherapy, the 5 year CI of tMDS/tAML was 2.1%. tMDS/tAML can be a long-term therapeutic complication, affecting more frequently patients aged ≥50 years and conferring a poor prognosis. Despite the lack of alkylating agents in the therapy of APL, cytogenetic abnormalities involving chromosomes 5 and 7 were frequently observed.

Central Nervous System Relapse in Patients with Acute Promyelocytic Leukemia Treated with All-Trans Retinoic Acid and Reinforced Anthracycline Monochemotherapy.

Background: Central nervous system (CNS) relapse can complicate the course of patients with acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) and chemotherapy, especially of those with high WBC at diagnosis (≥10 × 109/L). While ATRA and anthracyclines do not crosses the cerebrospinal fluid barrier, some trials for APL includes the use of intratechal prophylaxis or high-dose cytarabine, at least in high-risk patients, to avoid the CNS relapses. However, the convenience of CNS prophylaxis in APL patients is a matter of controversy.Objectives: Analyze the incidence and characteristics of CNS involvement at first relapse, in patients with newly diagnosed APL treated with ATRA and reinforced anthracycline monochemotherapy, without CNS prophylaxis.Methods: From 1999 to 2005, 564 patients (median age 40 years, range 2-83) were included in the PETHEMA LPA99 trial. Induction therapy consisted of ATRA and idarubicin. Patients in CR received 3 monthly courses of risk-adapted consolidation therapy as follows:i.“low-risk” patients (WBC <10×109/l and platelets >40×109/l), idarubicin 5 mg/m2/d × 4 (course #1), mitoxantrone 10 mg/m2/d × 5 (course #2), and idarubicin 12 mg/m2/d × 1 (course #3);ii.“intermediate-risk “ (WBC <10×109/l and platelet <40×109/l) and “high-risk” (WBC >10×109/l) patients received ATRA (45 mg/m2/d × 15) in combination with reinforced chemotherapy (Idarubicin 7 mg/m2/d in the course #1 and two days instead of one in the course #3).Maintenance therapy consisted of low-dose oral chemotherapy (mercaptopurine and methotrexate with ATRA). We measured the cumulative incidence (CI) of CNS involvement at first relapse during the course of APL patients who achieved the CR.Results: CR was achieved in 511 patients (91%). The median follow-up of the cohort was 57 months (range 20–94 months). Overall, 52 patients relapsed, of whom 5 presented a first relapse in CNS. In all cases, CNS relapses occurred without bone marrow or other extramedullary involvement. CNS relapses occurred after a median of 14 months (range 10–41 months) from the achievement of CR. At the initial diagnosis, APL were classified, according to the Sanz score, as low-, intermediate- and high-risk, in 0, 2, and 3 patients, respectively. The median WBC at diagnosis was 34.5 × 109/L (range 1.9–68.8 × 109/L), and 4 patients showed a Bcr3 PML-RARalpha isoform. Using a competitive-risk method, the overall 5 year CI of CNS relapse was 1.03%. The 5 year CI of CNS relapse in low-, intermediate- and high-risk patients was 0%, 0.77% and 2.71%, respectively (low- vs high-risk and intermediate vs high-risk; p=0.12 and p=0.11, respectively). The 5 year CI of CNS relapse in patients with Bcr3 and Bcr1 PML-RARalpha isoform was 0.45% and 2.44%, respectively (p=0.12).Conclusion: Despite the lack of intratechal prophylaxis or high-dose cytarabine in the therapeutic schedule of the LPA99 trial, the overall 5 year CI of CNS relapse was very low (1%). Our results does not hold up the systematic use of CNS prophylaxis in APL patients treated with ATRA and reinforced anthracycline monochemotherapy.

Risk-Adapted Treatment of Acute Promyelocytic Leukemia: Updated Results of the Spanish PETHEMA LPA99 Trial Using ATRA and Anthracycline Monochemotherapy.

Background: A first report of the PETHEMA LPA99 trial in acute promyelocytic leukemia (APL) showed that a risk-adapted treatment strategy combining ATRA and anthracycline alone for induction and consolidation results in high antileukemic efficacy and low toxicity. We report here an updated analysis of this trial including a significantly higher number of patients and longer follow-up.Methods: From November 1999 to July 2005, 564 patients (median age 40 years, range 2–83) with APL received induction with ATRA (45 mg/m2/d) until CR and idarubicin (12 mg/m2/d) on days 2, 4, 6 and 8. Patients in CR received 3 monthly courses of risk-adapted consolidation therapy as follows:i.“low-risk” patients (WBC <10×109/l and platelets >40×109/l), idarubicin 5 mg/m2/d × 4 (course #1), mitoxantrone 10 mg/m2/d × 5 (course #2), and idarubicin 12 mg/m2/d × 1 (course #3);ii.“intermediate-risk “ (WBC <10×109/l and platelet <40×109/l) and “high-risk” (WBC >10×109/l) patients received ATRA (45 mg/m2/d × 15) in combination with reinforced chemotherapy (Idarubicin 7 mg/m2/d in the course #1 and two days instead of one in the course #3).Maintenance therapy consisted of 50 mg/m2/d mercaptopurine orally, 15 mg/m2/week methotrexate intramuscularly, and 45 mg/m2/d ATRA for 15 days every 3 months.Results: CR was achieved in 511 patients (91%). Except for three cases labelled as resistant, of the remaining 50 patients 56%, 24%, 16% and 4% died due to hemorrhage, infection, retinoic acid syndrome, and acute myocardial infarction, respectively. Multivariate analysis showed that WBC >10×109/l, age >60 years, male gender, and serum creatinine >1.4 mg/dl at presentation had independent predictive value of death during induction. The median follow-up of the cohort was 57 months (range 20–94 months). Thirteen patients (median age 72 years, range 4–81) died in remission and 99% of patients completed the entire assigned therapy. Thirty-six patients presented haematological relapse, 16 molecular relapse, and 8 secondary myelodysplastic syndrome or acute myeloid leukemia. Overall, the 5-year cumulative incidence of relapse (CIR), disease-free survival, and overall survival were 11%, 85%, and 84%, respectively. The 5-year CIR for low-, intermediate- and high-risk patients were 4%, 7% and 28%, respectively.Conclusions: A risk-adapted strategy combining ATRA and anthracycline monochemotherapy for induction and consolidation therapy results in high antileukemic efficacy, low toxicity and a high degree of compliance in newly diagnosed APL.

Incidence and Risk Factors for Thrombosis in Patients with Acute Promyelocytic Leukemia. Experience of the PETHEMA LPA96 and LPA99 Protocols.

Background: Thrombo-ischemic events can be a severe complication in patients with active acute promyelocytic leukemia (APL). In a recently published study, the incidence of thrombosis among 90 patients with APL was 9%, and it was related to CD2 surface antigen expression, FLT3 mutations and leukocytes >10×109/L. The introduction of coagulopathy prophylaxis with tranexamic acid has not shown a benefit on hemorrhagic mortality, but its impact on the incidence of thrombotic events is unclear.Objectives:Analyze the incidence and risk factors for the development of thrombosis in patients with APL undergoing induction chemotherapy.Analyze the impact of prophylaxis with tranexamic acid on development of thrombosis.Material and methods: Between 1996 and 2005 759 patients with newly diagnosed APL were registered in the multicenter PETHEMA LPA96 and LPA99 trials. Twenty-six patients (3.5%) died due to complications before start of chemotherapy (CT). Induction consisted of ATRA plus idarubicin. In the LPA99 trial prophylactic tranexamic acid 100 mg/kg/day was introduced in case of platelets <50×109/L. At the end of the LPA99 trial its use was not recommended, and overall, initiation of tranexamic acid was reported in 257 patients (35%) We performed a univariate analysis to assess clinico-biological factors associated with thrombosis. Significant variables (p<0.05) were included in a multivariate analysis.Results: 39/759 patients (5.1%) developed thrombosis. Among 26 patients who died before initiation of CT, 6 (23%) presented with thrombotic complications: 3 cerebral stroke (CNS), 2 pulmonary embolism (PE) and 1 acute myocardial infarction (AMI). Thirty-three (4.5%) of the 733 patients in whom CT was initiated experienced thrombosis: 3 at diagnosis (1 AMI, 1 CNS and 1 deep venous thrombosis (DVT)) and 30 after the start of CT (16 DVT, 6 CNS, 3 PE, 2 AMI and 2 others). Four thrombotic events were related with initiation of tranexamic acid: 2 DVT, 1 skin necrosis and 1 renal necrosis. The following factors were related to a higher incidence of thrombosis: leukocytes >10×109/L (9% vs 4%, p<0.01), M3-variant subtype (11% vs 4%, p=0.02), fibrinogen <170 mg/dl (7% vs 3%, p=0.02) and hemoglobin >10 g/dl (8% vs 4%, p=0.03). No significant relation was observed with CD2 or other surface antigens, as well as FLT3 mutations. Use of tranexamic acid showed a trend towards a higher incidence of thrombosis (6% vs 3%, p=0.08). In multivariate analysis hypofibrinogenemia and M3-v subtype remained as independent prognostic factors. Thrombosis was related with a higher induction mortality (including deaths before start of CT), 28% vs 11%, p<0.01.Conclusion: Thrombo-ischemic events are relatively frequent in active APL patients implying an elevated early mortality. Hypofibrinogenemia and M3-v are associated with a higher incidence of thrombosis. Treatment with tranexamic acid has not decreased hemorrhagic mortality and it could be related to increased thrombotic events. Therefore its prophylactic use should not be recommended.

Predictive Factors of All Trans-Retinoic Acid (ATRA) Related Complications during Induction Course of Acute Promyelocytic Leukemia (APL).

Background: The combination of ATRA and chemotherapy has made APL a highly curable leukemia. However several complications are reported with this treatement the most serious and life threatening being ATRA syndrome. We aimed at identifying factors that could predict complications caused by ATRA during induction treatement of APL.Patients: 42 patients with comfirmed APL(by t(15,17) and/or PML/RARA) treated at our institution (University hospital of Tunis) between January 1998 and June 2006 using two consecutive protocols: European APL93 trial (24 patients) until February 2004 and Spanish PETHEMA LPA99 trial (18 patients) more recently. Induction regimen consisted of ATRA 45 mg/m2/d until CR combined to DNR 60 mg/m2/d×3 + Cytarabine 200 mg/m2/d×7 (APL93) and Idarubicin 12 mg/m2 d2,4,6,8 (LPA99). Prednisone (0,5 mg/kg d1–d15) was added if WBC > 10 000/mm3 to prevent ATRA syndrome in LPA 99.Results: Median age was 36 yr (7–64yr), M/F=16/26(0,61), median WBC was 2400/mm3(range 600–100 000/mm3). WBC>10 000/mm3 was noted in 14 patients (33%). Additional cytogenetic abnormalities were seen in 12/42(28%). Median Body Mass Index(BMI= weight/length2:N 20–25) was 24kg/m2(range 16–40kg/m2), BMI>30 was noted in 9 patients(8F and 1M).33 patients achieved CR (78,57%):18/24 (75%) in APL93 vs 15/18(83%) in LPA99.9 patients(21,42%) had early death. Causes of early death were:ATRA syndrome(6) and CNS haemorrhage (3). Complications due to ATRA were:ATRA syndrome(10), Scrotal ulcerations(3), Sweet syndrome(2), Perineal ulcerations(1), Pseudotumor cerebri (1). Prognostic factors for complications of ATRA(Fisher exact test) were:BMI>35 (p=0,055), induction treatment without cytarabine(LPA99 trial) (p=0,047), whereas age(p=0,74), gender (p=0,51), initial WBC (p=0,47), and additional cytogenetic abnormalities were not predictive. ATRA syndrome was more reported in patients with initial WBC>10 000 (p=0,08).Conclusion: We found high BMI (>35) in female and treatement without Cytarabine to increase the risk of developping complications with ATRA.

Retinoic Acid Syndrome in Patients with Acute Promyelocytic Leukemia Treated with All-Trans Retinoic Acid and Anthracycline Monochemotherapy.

Retinoic acid syndrome (RAS) can be a life-threatening complication in patients with acute promyelocytic leukemia (APL) undergoing induction therapy with all-trans retinoic acid (ATRA). Incidence of RAS has been reported ranging from 2% to 30%. It has been suggested that patients with leukocytes >5 x109/L at presentation are at high risk for the development of RAS. The impact of RAS on long term outcome is still a matter of controversy. We analyze the incidence, prognostic factors and outcome of RAS in 733 patients with newly diagnosed APL enrolled in the PETHEMA LPA96 and LPA99 trials (175 and 558 patients, respectively). Induction therapy consisted of ATRA and idarubicin, followed by three consolidation courses of anthracycline monochemotherapy. In the LPA99 trial, ATRA was added in each cycle of consolidation, except for low-risk patients. In the LPA99 trial, all patients received RAS prophylaxis with oral prednisone (0.5 mg/kg). Temporary discontinuation of ATRA and treatment with intravenous dexamethasone were recommended at the first signs of suspected RAS, in both trials. Definite RAS was defined as the presence of at least four of the following criteria: unexplained fever, respiratory distress, radiological pulmonary infiltrates, pericardial/pleural effusion, hypotension, renal failure, and weight gain over 5 kg. Overall, 87 patients (12%) experienced RAS, after a median of 6 days of ATRA (range, 0 to 46). Forty-seven cases (54%) occurred from days 0 to 7, 4 (5%) from days 8 to 14, 32 (36%) from days 15 to 30, and 4 (5%) from days 31 to 46. The main clinical signs were pulmonary infiltrates (83%), fever (80%), weight gain (74%), pleural effusion (63%) and renal failure (49%). ATRA was discontinued in 63% of patients. RAS was associated with age >50 years (41% vs 29%, p=0.02), serum level of creatinine >1.4 mg/dl (9% vs 3%, p<0.01) and leukocytes at presentation >5x109/L (46% vs 32%, p=0.01). Leukocytes >5x109/L and creatinine >1.4 mg/dl remained as independent prognostic factors in multivariate analysis. The incidence of RAS was not statistically different between the LPA96 (without prednisone prophylaxis) and LPA99 trials (15% vs 11%, p=0.16). RAS was associated with induction death (26% vs 7%, p<0.01) and was the main cause of death in 10 patients (1.4%). Age >60 years, leukocytes >10x109/L, RAS, male gender and serum creatinine level >1.4 mg/dl at presentation were independent prognostic factors for induction death. Patients developing RAS had a higher cumulative incidence of relapse (CIR) in the LPA96 trial (40% vs 15%, p<0.01), but there were no significant differences in the LPA99 trial (12% vs 13%). In conclusion, we have observed a bimodal peak incidence of RAS during the induction phase, with the first peak from days 0 to 7 and the second peak from days 15 to 30. Patients with leukocytes >5x109/L and serum creatinine level >1.4 mg/dl are at high risk for development of RAS, which is an adverse prognostic factor for induction death. The negative impact of RAS on CIR among patients treated with the LPA96 trial was not observed in the LPA99, in which patients received additional doses of ATRA for consolidation therapy.

FLT3 Mutations in a Large Series of Patients with Acute Promyelocytic Leukemia Treated with All-Trans Retinoic Acid and Anthracycline Monochemotherapy.

Background: The prognostic significance of FLT3 internal tandem duplication (ITD) and D835 mutations in acute promyelocytic leukemia (APL) remains unclear. Recent studies have revealed an association between FLT3 mutations and leukocytes > 10x109/L, M3-variant subtype and BCR3 isoform. It has been also suggested that patients with FLT3 mutations have a higher induction death rate and a shorter survival. Objectives: To analyze in patients with newly diagnosed APL treated with an ATRA plus anthracycline-based protocol if the presence of FLT3 ITD and D835 mutations influences the clinical and biological presenting features, and the disease outcome.Material and methods: Between 1997 and 2005, 733 consecutive patients were enrolled in the PETHEMA LPA96 and LPA99 trials. Treatment consisted of Induction therapy with oral ATRA (45 mg/m2/d) and intravenous idarubicin (12 mg/m2/d x 4 days) followed by three courses of consolidation with anthracycline monochemotherapy. In the LPA99 trial, ATRA was added in each cycle of consolidation for intermediate and high risk patients (according to Sanz score). In both trials, maintenance therapy consisted of intermittent ATRA and low dose chemotherapy with methotrexate and 6-mercaptopurine. Using RT-PCR, analysis of the FLT3 ITD and D835 mutations was available in 251 and 191 patients respectively.Results: Overall, 61 patients (24%) had a FLT3 ITD mutation and 20 patients (10%) had a FLT3 D835 mutation. Only one patient had both mutations. FLT3 ITD was associated with BCR3 isoform (78% vs 32%, p < 0.01), leukocytes > 10x109/L (64% vs 17%, p < 0.01), M3v subtype (46% vs 13%, p < 0.01), bone marrow blasts > 70% (95% vs 80%, p < 0.01) and expression of CD2 and CD34 surface antigens (41% vs 14% and 38% vs 9%, respectively, p < 0.01). FLT3 D835 was not associated with leukocytes > 10x109/L (35% vs 25%, p=0.31) or any other biological characteristic. There was a trend towards a higher induction death rate in patients with FLT3 ITD or D835 mutations, when compared to patients with wild-type FLT3 (15% vs 16% vs 6%, respectively, p=0.08). There was no significant difference on relapse-free survival (RFS) and overall survival (OS) at 7 years in patients with FLT3 ITD, when compared to those with FLT3 D835 or wild-type FLT3 (81% vs 100% vs 87% for RFS, p=0.17; and 76% vs 84% vs 81% for OS, p=0.37).Conclusion: In a large cohort of patients with newly diagnosed APL, the incidence of FLT3 ITD and FLT3 D835 mutations was 24% and 10%. This study was only able to demonstrate an association of FLT3 ITD with leukocytes > 10x109/L, M3v subtype, BCR3 isoform, and expression of CD2 and CD34 surface antigens, but this mutation had no independent prognostic value in patients with APL receiving state-of-the-art treatment.