High-dose cytarabine and mitoxantrone in consolidation therapy for acute promyelocytic leukemia

Additional cytogenetic abnormalities in patients with newly diagnosed acute promyelocytic leukemia predict inferior event-free survival

BACKGROUND

The innovative combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has established a new chapter of curative approach in acute promyelocytic leukemia (APL). The disease characteristics and prognostic influence of additional cytogenetic abnormalities (ACA) in APL with modern therapeutic strategy need to be elucidated.

METHODS

In the present study, we retrospectively investigated disease features and prognostic power of ACA in 171 APL patients treated with ATRA-ATO-containing regimens.

RESULTS

Patients with ACA had markedly decreased hemoglobin levels than that without ACA (p = 0.021). Risk stratification in the ACA group was significantly worse than that in the non-ACA group (p = 0.032). With a median follow-up period of 62.0 months, worse event-free survival (EFS) was demonstrated in patients harboring ACA. Multivariate analysis showed that ACA was an independent adverse factor for EFS (p = 0.033). By further subgroup analysis, in CD34 and CD56 negative APL, patients harboring ACA had inferior EFS (p = 0.017; p = 0.037).

CONCLUSIONS

To sum up, ACA remains the independent prognostic value for EFS, we should build risk-adapted therapeutic strategies in the long-term management of APL when such abnormalities are detected.

Case Report: Co-existence of a novel EXOC4-TRHDE gene fusion with PML-RARA in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a type of myeloid leukemia with a specific chromosomal translocation t(15;17)(q22; q12) forming the PML-RARA fusion gene. However, approximately one third of newly diagnosed patients with APL have additional chromosomal abnormalities. Here, we report a case of APL with co-existence of a novel translocation t(7;12)(q32;q13) involving an out-of-frame fusion between EXOC4 and TRHDE, together with PML-RARA. The patient achieved complete remission after treatment with conventional therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Although the causative link between EXOC4-TRHDE and PML-RARA has yet to be established, the patient had a good response to therapy, suggesting that the EXOC4-TRHDE fusion does not affect the efficacy of combined treatment with ATRA and ATO.

Cytogenetic Influence on Prognosis in Acute Promyelocytic Leukaemia: A Cohort Study in Vietnam

OBJECTIVE/BACKGROUND

To analyse the influence of chromosomal aberrations in addition to t(15;17)(q22;q21) in acute promyelocytic leukaemia (APL) on clinical characteristics and treatment outcomes.

METHODS

Fifty-seven patients with new APL diagnoses underwent conventional cytogenetic analysis; fluorescence in situ hybridization for t(15;17)(q22;q21) and reverse transcriptase-polymerase chain reaction detected PML/RARα in two forms: L (length) and S (short) and accepted treatment with all-trans retinoic acid and chemotherapy. Patients with additional chromosome aberrations were designated as the complex karyotype group and were compared with patients with only t(15;17), who were designated as the simple karyotype group.

RESULTS

Additional chromosome aberrations was observed in 18/57 patients (31.6%) at initial diagnosis. Outcome was significantly different between the simple karyotype group and the complex karyotype group for complete remission (92.3% vs. 66.7% respectively, p = .025), overall survival at 3 years (92.3% vs. 65.0%, respectively, p = .017), and progression-free survival at 3 years (81.4% vs. 44.4%, respectively, p = .024).

CONCLUSIONS

Additional chromosome aberrations had adverse effects on the prognosis in APL.

Outcome of older (≥70 years) APL patients frontline treated with or without arsenic trioxide-an International Collaborative Study

Data on outcome in older (≥70 years) patients with acute promyelocytic leukemia after treatment with arsenic trioxide (ATO) compared with standard chemotherapy (CTX) is scarce. We evaluated 433 patients (median age, 73.4 years) treated either with ATO+ all-trans retinoic acid (ATO/ATRA; n = 26), CTX/ATRA + ATO during consolidation (CTX/ATRA/ATO; n = 148), or with CTX/ATRA (n = 259). Median follow-up for overall survival (OS) was 4.8 years. Complete remissions (CR) were achieved in 92% with ATO/ATRA and 82% with CTX/ATRA; induction death rates were 8% and 18%, respectively. For analysis of postremission outcomes we combined the ATO/ATRA and CTX/ATRA/ATO groups (ATO/ATRA ± CTX). Cumulative incidence of relapse (CIR) was significantly lower after ATO/ATRA ± CTX compared with CTX/ATRA (P < 0.001). The same held true when restricting the analysis according to the treatment period after the year 2000. OS of patients in CR1 was not different between ATO/ATRA ± CTX compared with CTX/ATRA (P = 0.20). High (>10 × 10⁹/l) white blood cell (WBC) counts at diagnosis were associated with higher CIR (P < 0.001) compared with lower WBC in the CTX/ATRA group, but not in the ATO/ATRA ± CTX group (P = 0.48). ATO, when added to ATRA or CTX/ATRA is feasible and effective in elderly patients for remission induction and consolidation, particularly in patients with high WBC at diagnosis.

Clinical significance of complex karyotype at diagnosis in pediatric and adult patients with de novo acute promyelocytic leukemia treated with ATRA and chemotherapy

Although additional cytogenetic abnormalities (ACA) do not affect the prognosis of patients with t(15;17) acute promyelocytic leukemia (APL), the role of a complex karyotype (CK) is yet to be clarified. We aimed to investigate the relationship of CK with relapse incidence in 1559 consecutive APL patients enrolled in three consecutive trials. Treatment consisted of AIDA induction followed by risk-adapted consolidation. A CK (CK) was defined as the presence of ≥2 ACA, and a very CK (CK+) as ≥3 ACA. Eighty-nine patients (8%) had a CK, of whom 41 (4%) had CK+. The 5-year cumulative incidence of relapse (CIR) in patients with CK was 18%, and 12% in those with <2 ACA (p=.09). Among patients with CK+, the 5-year CIR was 27% vs 12% (p=.003), retaining the statistical significance in multivariate analysis. This study shows an increased risk of relapse among APL patients with CK + treated with ATRA plus chemotherapy front-line regimens.

Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

RaRF confers RA resistance by sequestering RAR to the nucleolus and regulating MCL1 in leukemia cells

Retinoic acid (RA) has broad clinical applications for the treatment of various cancers, particularly acute promyelocytic leukemia. However, RA-based therapy is limited by relapse in patients associated with RA resistance, the mechanism of which is poorly understood. Here, we suggest a new molecular mechanism of RA resistance by a repressor, named RA resistance factor (RaRF). RaRF suppressed transcriptional activity of the RA receptor (RAR) by directly interacting with and sequestering RAR to the nucleolus in response to RA. RaRF was highly expressed in RA-resistant leukemia cells and its expression was strongly correlated with RA sensitivity. MCL1 was upregulated by RA treatment upon RaRF depletion, accompanying leukemic myeloblast differentiation, which is negatively regulated by ectopic RaRF expression. Collectively, we propose that RaRF may be a factor in the resistance mechanism and thus a potential target for leukemia therapy using RA.

Arsenic Trioxide Consolidation Allows Anthracycline Dose Reduction for Pediatric Patients With Acute Promyelocytic Leukemia: Report From the Children's Oncology Group Phase III Historically Controlled Trial AAML0631

Purpose The Children's Oncology Group AAML0631 trial for newly diagnosed pediatric acute promyelocytic leukemia (APL) was a phase III historically controlled trial to determine the survival of patients receiving arsenic trioxide (ATO) consolidation and reduced doses of anthracyclines. Patients and Methods Patients age 2 to 21 years with de novo APL confirmed by PML-RARα polymerase chain reaction were stratified as standard risk (SR) or high risk (HR) on the basis of diagnostic WBC count. All patients received all-trans retinoic acid (ATRA) during induction, each consolidation course, and maintenance. All patients received two cycles of ATO therapy during consolidation 1, an additional two (SR) or three (HR) consolidation courses that included high-dose cytarabine and anthracycline, and maintenance therapy comprising ATRA, oral methotrexate, and mercaptopurine. Results One hundred one patients (66 SR and 35 HR) were evaluable for outcome. The 3-year overall survival was 94%, and event-free survival (EFS) was 91%. For SR and HR patients with APL, the overall survival was 98% versus 86% ( P = .003), and EFS was 95% versus 83% ( P = .03), respectively. The EFS for SR patients in AAML0631 was noninferior to that of patients in the AIDA 0493 historical control, which used a significantly higher anthracycline dose and did not include ATO consolidation. Relapse risk for patients in AAML0631 from end consolidation 1 (after ATO treatment) was only 4% at 3 years and did not differ significantly between SR and HR patients. Conclusion ATO consolidation cycles were well tolerated in pediatric patients with APL and allowed significant reduction in cumulative anthracycline doses while maintaining excellent survival and a low relapse risk for both SR and HR patients with APL.

Recurrent bowel-blood translocations of Escherichia coli with the unique virulence characteristics over three-year period in the patient with acute myeloid leukaemia - case report

In patients with haematological malignancies, the bowel remains the main source of Escherichia coli bloodstream infections. We present the clinical example of recurrent bowel-blood translocations of E. coli with the unique virulence characteristics in a 55-year-old male with the diagnosis of acute myeloid leukaemia. The virulent factors profile of examined strains confirmed that the co-existence of genes papC, sfa, usp and cnf1, encoding virulence factors, predisposes E. coli to translocation from the gastrointestinal tract to the vascular bed. The close cooperation between haematologists and microbiologists is essential to improve the outcome of patients colonised with highly pathogenic strains.

ASXL1 mutations in younger adult patients with acute myeloid leukemia: a study by the German-Austrian Acute Myeloid Leukemia Study Group

We studied 1696 patients (18 to 61 years) with acute myeloid leukemia for ASXL1 mutations and identified these mutations in 103 (6.1%) patients. ASXL1 mutations were associated with older age (P<0.0001), male sex (P=0.041), secondary acute myeloid leukemia (P<0.0001), and lower values for bone marrow (P<0.0001) and circulating (P<0.0001) blasts. ASXL1 mutations occurred in all cytogenetic risk-groups; normal karyotype (40%), other intermediate-risk cytogenetics (26%), high-risk (24%) and low-risk (10%) cytogenetics. ASXL1 mutations were associated with RUNX1 (P<0.0001) and IDH2(R140) mutations (P=0.007), whereas there was an inverse correlation with NPM1 (P<0.0001), FLT3-ITD (P=0.0002), and DNMT3A (P=0.02) mutations. Patients with ASXL1 mutations had a lower complete remission rate (56% versus 74%; P=0.0002), and both inferior event-free survival (at 5 years: 15.9% versus 29.0%; P=0.02) and overall survival (at 5 years: 30.3% versus 45.7%; P=0.0004) compared to patients with wildtype ASXL1. In multivariable analyses, ASXL1 and RUNX1 mutation as a single variable did not have a significant impact on prognosis. However, we observed a significant interaction (P=0.04) for these mutations, in that patients with the genotype ASXL1(mutated)/RUNX1(mutated) had a higher risk of death (hazard ratio 1.8) compared to patients without this genotype. ASXL1 mutation, particularly in the context of a coexisting RUNX1 mutation, constitutes a strong adverse prognostic factor in acute myeloid leukemia.

Acute promyelocytic leukaemia with a PML-RARA insertional translocation and a chromosome 21 abnormality in XYY syndrome: case report

The concomitant presence of the XYY syndrome with haematological malignancies is rare. This report presents a case of acute promyelocytic leukaemia (APL) with the promyelocytic leukaemia-retinoic acid receptor alpha (PML-RARA) gene insertional translocation and a chromosome 21 abnormality in a 29-year-old XYY male patient. Karyotype analysis revealed an abnormal karyotype of 47,XYY [14]/46,XYY,-21[16]. Fluorescence in situ hybridization and reverse transcription-polymerase chain reaction analysis showed the existence of a PML-RARA fusion gene. The patient was treated by all-trans retinoic acid (ATRA) and chemotherapy. Laboratory results revealed that the coagulopathy improved and the patient achieved complete remission, based on bone-marrow morphology. The patient then received sequential monthly therapy using arsenic trioxide, followed by ATRA, followed by chemotherapy; he has survived disease-free for 36 months. Our findings suggest that the additional chromosomal abnormalities involving the sex chromosomes and chromosome 21 did not affect the prognosis of APL, and that the sequential treatment strategy had a good clinical effect without being associated with severe side-effects.

Arsenic trioxide in front-line therapy of acute promyelocytic leukemia (C9710): prognostic significance of FLT3 mutations and complex karyotype

The addition of arsenic trioxide (ATO) to frontline therapy of acute promyelocytic leukemia (APL) has been shown to result in significant improvements in disease-free survival (DFS). FLT3 mutations are frequently observed in APL, but its prognostic significance remains unclear. We analyzed 245 newly diagnosed adult patients with APL treated on intergroup trial C9710 and evaluated previously defined biological and prognostic factors and their relationship to FLT3 mutations and to additional karyotypic abnormalities. FLT3 mutations were found in 48% of patients, including 31% with an internal tandem duplication (FLT3-ITD), 14% with a point mutation (FLT3-D835) and 2% with both mutations. The FLT3-ITD mutant level was uniformly low, < 0.5. Neither FLT3 mutation had an impact on remission rate, induction death rate, DFS or overall survival (OS). The addition of ATO consolidation improved outcomes regardless of FLT3 mutation type or level, initial white blood cell count, PML-RARA isoform type or transcript level. The presence of a complex karyotype was strongly associated with an inferior OS independently of post-remission treatment. In conclusion, the addition of ATO to frontline therapy overcomes the impact of previously described adverse prognostic factors including FLT3 mutations. However, complex karyotype is strongly associated with an inferior OS despite ATO therapy.

Long-term prognosis of childhood acute promyelocytic leukaemia with arsenic trioxide administration in induction and consolidation chemotherapy phases: a single-centre experience

OBJECTIVES

The efficacy of all-trans retinoic acid (ATRA) and arsenic trioxide (As2 O3 ) as induction therapy for adult acute promyelocytic leukaemia (APL) has been documented in several clinical trials. However, the role of ATRA/As2 O3 combination in induction and consolidation therapy in children remains unclear. Here, we report the efficacy of combined treatment with As2 O3 and ATRA as induction and consolidation chemotherapy to treat newly diagnosed childhood APL.

METHODS

From 1998 to 2011, 43 children with newly diagnosed APL received induction and consolidation chemotherapy with ATRA and As2 O3 (Protocol B). Rates of complete remission (CR), event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) and drug toxicity were compared between children treated with Protocol B and 25 others treated previously with ATRA alone as induction chemotherapy (Protocol A).

RESULTS

Of 43 patients treated with Protocol B, 41 (95.4%) achieved CR (two died of intracranial haemorrhage on day 10 and 14). In contrast, only 20 (80%) of 25 patients treated with Protocol A achieved CR. Thus, the CR rate was significantly lower in patients receiving induction chemotherapy with Protocol A than in those treated with Protocol B (P = 0.045, χ(2) = 6.508). Of the 41 patients who achieved CR on induction therapy with Protocol B, 40 also received consolidation therapy. Molecular relapse, but no overt morphological relapse, occurred in one patient at 25 months after diagnosis; this patient regained CR status with As2 O3 treatment. With a median follow-up period of 75 months, estimated EFS, DFS and OS rates were 92.5 ± 4.2%, 97.1 ± 2.9% and 95.3 ± 3.2%, respectively, for Protocol B. In contrast, with a median follow-up of 127 months, the EFS, DFS and OS rates at 75 months were 70.4 ± 9.4%, 76.4 ± 9.2% and 70.4 ± 9.4%, respectively, for Protocol A. Thus, patients treated with Protocol A showed significantly lower EFS (P = 0.021) and OS (P = 0.007) rates than those treated with Protocol B.

CONCLUSIONS

Application of As2 O3 and ATRA as induction and consolidation chemotherapy resulted in excellent outcomes and improved long-term prognosis in children with newly diagnosed APL.

Monosomal karyotype in adult acute myeloid leukemia: prognostic impact and outcome after different treatment strategies

We aimed to determine the prognostic impact of monosomal karyotype (MK) in acute myeloid leukemia (AML) in the context of the current World Health Organization (WHO) classification and to evaluate the outcome of MK+ patients after allogeneic HSCT. Of 1058 patients with abnormal cytogenetics, 319 (30%) were MK MK+. MK+ patients were significantly older (P = .0001), had lower white blood counts (P = .0006), and lower percentages of BM blasts (P = .0004); MK was associated with the presence of −5/5q−, −7, 7q−, abnl(12p), abnl(17p), −18/18q−, −20/20q−, inv(3)/t(3;3), complex karyotype (CK), and myelodysplasia (MDS)–related cytogenetic abnormalities (P < .0001, each); and NPM1 mutations (P < .0001), FLT3 internal tandem duplications (P < .0001), and tyrosine kinase domain mutations (P = .02) were less frequent in MK+. Response to induction therapy and overall survival in MK+ patients were dismal with a complete remission rate of 32.5% and a 4-year survival of 9%. MK retained its prognostic impact in AML with CK, AML with MDS-related cytogenetic abnormalities, and in a revised definition (MK-R) excluding cases with recurrent genetic abnormalities according to WHO classification and those with derivative chromosomes not leading to true monosomies. In younger patients, allogeneic HSCT from matched related and unrelated donors resulted in a limited improvement of overall survival.

FLT3 inhibitors in acute myeloid leukemia

The fms-like tyrosine kinase 3 (FLT3) plays an important role in both normal and malignant hematopoiesis. Activating mutations in the FLT3 receptor can be detected in approximately 30% of acute myeloid leukemias (AMLs) and are associated with a distinctly poor clinical outcome for patients. There are now several classes of FLT3 inhibitors in development with varying degrees of potency and selectivity for the target, including several in late-phase clinical trials in combination with chemotherapy. Major clinical responses in AML patients receiving single-agent FLT3 inhibitors have been rare, although transient peripheral blood blast reduction is common. Given such biological suggestion and preclinical activity, FLT3 inhibitors hold promise in improving the outcome of patients with mutant FLT3 AML. This review summarizes the current attempts to target this molecule, with emphasis on the validity of the target, the results of the clinical trials evaluating the FLT3 inhibitors in AML, the optimal use of these compounds and the mechanisms of resistance.

RUNX1 mutations in acute myeloid leukemia: results from a comprehensive genetic and clinical analysis from the AML study group

PURPOSE

To evaluate frequency, biologic features, and clinical relevance of RUNX1 mutations in acute myeloid leukemia (AML).

PATIENTS AND METHODS

Diagnostic samples from 945 patients (age 18 to 60 years) were analyzed for RUNX1 mutations. In a subset of cases (n = 269), microarray gene expression analysis was performed.

RESULTS

Fifty-nine RUNX1 mutations were identified in 53 (5.6%) of 945 cases, predominantly in exons 3 (n = 11), 4 (n = 10), and 8 (n = 23). RUNX1 mutations clustered in the intermediate-risk cytogenetic group (46 of 640, 7.2%; cytogenetically normal, 34 of 538, 6.3%), whereas they were less frequent in adverse-risk cytogenetics (five of 109, 4.6%) and absent in core-binding-factor AML (0 of 77) and acute promyelocytic leukemia (0 of 61). RUNX1 mutations were associated with MLL-partial tandem duplications (P = .0007) and IDH1/IDH2 mutations (P = .03), inversely correlated with NPM1 (P < .0001), and in trend with CEBPA (P = .10) mutations. RUNX1 mutations were characterized by a distinct gene expression pattern; this RUNX1 mutation-derived signature was not exclusive for the mutation, but also included mostly adverse-risk AML [eg, 7q-, -7, inv(3), or t(3;3)]. RUNX1 mutations predicted for resistance to chemotherapy (rates of refractory disease 30% and 19%, P = .047, for RUNX1-mutated and wild-type patients, respectively), as well as inferior event-free survival (EFS; P < .0001), relapse-free survival (RFS, P = .022), and overall survival (P = .051). In multivariable analysis, RUNX1 mutations were an independent prognostic marker for shorter EFS (P = .007). Explorative subgroup analysis revealed that allogeneic hematopoietic stem-cell transplantation had a favorable impact on RFS in RUNX1-mutated patients (P < .0001).

CONCLUSION

AML with RUNX1 mutations are characterized by distinct genetic properties and are associated with resistance to therapy and inferior outcome.

The impact of therapy-related acute myeloid leukemia (AML) on outcome in 2853 adult patients with newly diagnosed AML

To study the characteristics and clinical impact of therapy-related acute myeloid leukemia (t-AML). 200 patients (7.0%) had t-AML and 2653 de novo AML (93%). Patients with t-AML were older (P < .0001) and they had lower white blood counts (P = .003) compared with de novo AML patients; t-AML patients had abnormal cytogenetics more frequently, with overrepresentation of 11q23 translocations as well as adverse cytogenetics, including complex and monosomal karyotypes, and with underrepresentation of intermediate-risk karyotypes (P < .0001); t-AML patients had NPM1 mutations (P < .0001) and FLT3 internal tandem duplications (P = .0005) less frequently. Younger age at diagnosis of primary malignancy and treatment with intercalating agents as well as topoisomerase II inhibitors were associated with shorter latency periods to the occurrence of t-AML. In multivariable analyses, t-AML was an adverse prognostic factor for death in complete remission but not relapse in younger intensively treated patients (P < .0001 and P = .39, respectively), relapse but not death in complete remission in older, less intensively treated patients (P = .02 and P = .22, respectively) and overall survival in younger intensively treated patients (P = .01). In more intensively treated younger adults, treatment-related toxicity had a major negative impact on outcome, possibly reflecting cumulative toxicity of cancer treatment.

Prospective Evaluation of Allogeneic Hematopoietic Stem-Cell Transplantation From Matched Related and Matched Unrelated Donors in Younger Adults With High-Risk Acute Myeloid Leukemia: German-Austrian Trial AMLHD98A

Purpose

To assess the impact of allogeneic hematopoietic stem-cell transplantation (HSCT) from matched related donors (MRDs) and matched unrelated donors (MUDs) on outcome in high-risk patients with acute myeloid leukemia (AML) within a prospective multicenter treatment trial.

Patients and Methods

Between 1998 and 2004, 844 patients (median age, 48 years; range, 16 to 62 years) with AML were enrolled onto protocol AMLHD98A that included a risk-adapted treatment strategy. High risk was defined by the presence of unfavorable cytogenetics and/or by no response to induction therapy.

Results

Two hundred sixty-seven (32%) of 844 patients were assigned to the high-risk group. Of these 267 patients, 51 patients (19%) achieved complete remission but had adverse cytogenetics, and 216 patients (81%) had no response to induction therapy. Allogeneic HSCT was actually performed in 162 (61%) of 267 high-risk patients, after a median time of 147 days after diagnosis. Graft sources were as follows: MRD (n = 62), MUD (n = 89), haploidentical donor (n = 10), and cord blood (n = 1). The 5-year overall survival rates were 6.5% (95% CI, 3.1% to 13.6%) for patients (n = 105) not proceeding to HSCT and 25.1% (95% CI, 19.1% to 33.0%; from date of transplantation) for patients (n = 162) receiving HSCT. Multivariable analysis including allogeneic HSCT as a time-dependent covariable revealed that allogeneic HSCT significantly improved outcome; there was no difference in outcome between allogeneic HSCT from MRD and MUD.

Conclusion

Allogeneic HSCT in younger adults with high-risk AML has a significant beneficial impact on outcome, and allogeneic HSCT from MRD and MUD yields similar results.

IDH1 and IDH2 mutations are frequent genetic alterations in acute myeloid leukemia and confer adverse prognosis in cytogenetically normal acute myeloid leukemia with NPM1 mutation without FLT3 internal tandem duplication

PURPOSE

To analyze the frequency and prognostic impact of isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2) mutations in acute myeloid leukemia (AML).

PATIENTS AND METHODS

We studied 805 adults (age range, 16 to 60 years) with AML enrolled on German-Austrian AML Study Group (AMLSG) treatment trials AML HD98A and APL HD95 for mutations in exon 4 of IDH1 and IDH2. Patients were also studied for NPM1, FLT3, MLL, and CEBPA mutations. The median follow-up for survival was 6.3 years.

RESULTS

IDH mutations were found in 129 patients (16.0%) -IDH1 in 61 patients (7.6%), and IDH2 in 70 patients (8.7%). Two patients had both IDH1 and IDH2 mutations. All but one IDH1 mutation caused substitutions of residue R132; IDH2 mutations caused changes of R140 (n = 48) or R172 (n = 22). IDH mutations were associated with older age (P < .001; effect conferred by IDH2 only); lower WBC (P = .04); higher platelets (P < .001); cytogenetically normal (CN) -AML (P< .001); and NPM1 mutations, in particular with the genotype of mutated NPM1 without FLT3 internal tandem duplication (ITD; P < .001). In patients with CN-AML with the latter genotype, IDH mutations adversely impacted relapse-free survival (RFS; P = .02) and overall survival (P = .03), whereas outcome was not affected in patients with CN-AML who lacked this genotype. In CN-AML, multivariable analyses revealed a significant interaction between IDH mutation and the genotype of mutated NPM1 without FLT3-ITD (ie, the adverse impact of IDH mutation [RFS]; P = .046 was restricted to this patient subset).

CONCLUSION

IDH1 and IDH2 mutations are recurring genetic changes in AML. They constitute a poor prognostic factor in CN-AML with mutated NPM1 without FLT3-ITD, which allows refined risk stratification of this AML subset.

Prognostic significance of FLT3 internal tandem duplication and tyrosine kinase domain mutations in acute promyelocytic leukemia: a systematic review

The fms-like tyrosine kinase 3 (FLT3) gene aberrations, internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutations, are frequent in acute promyelocytic leukemia (APL). To evaluate their prognostic significance, we performed a systematic review and meta-analysis. Eleven studies covering a total of 1063 subjects were included in this review. Incidence of ITD and TKD mutations was 12-38% and 2-20%, respectively. In 9 of 11 studies, ITD was associated with high WBC count at the time of diagnosis, which is a known prognostic indicator in APL. Patients with ITD had inferior 3-year overall survival compared to patients without ITD (risk ratio 1.42, 95% CI: 1.04-1.95). Similarly, ITD was also associated with adverse 3-year disease-free survival (risk ratio 1.48, 95% CI: 1.02-2.15). There were only two studies that evaluated the association of TKD mutation in APL; both showed a trend towards worse survival in patients with mutated TKD. In conclusion, FLT3 ITD is associated with high WBC at diagnosis in patients with APL. Although the available literature is limited to observational studies, our systematic review suggests that FLT3 mutations, especially ITD, can adversely affect overall survival and disease-free survival in APL.

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.

Improved outcome for Chinese children with acute promyelocytic leukemia: a comparison of two protocols

OBJECTIVE

Acute promyelocytic leukemia (APL) is now highly curable, except in many developing countries. Introduction of current treatment strategies may improve the outcome for children with APL in these countries.

METHODS

The diagnosis was based on the FAB classification and detection of PML-RAR alpha rearrangement. From December 1999 to September 2004, 16 eligible children were treated with an intensive in-house protocol including high-dose AraC and anthracycline. Subsequently, 14 cases were treated with a less intensive protocol modified from the PETHEMA LPA99.

RESULTS

The 3.5 years event-free survival (EFS) was 37.5% (95% CI, 13.8-61.2%) for patients treated on initial protocol. The treatment failures were: six patients abandoned treatment (37.5%), two who died of intracranial hemorrhage at diagnosis (6.3%) and sepsis in remission (6.3%) respectively, and two who relapsed (12.5%). Those treated on modified PETHEMA had a 3.5 years EFS of 79.6% (95% CI, 52.9-106.3%). Treatment failures included: one who died of intracranial hemorrhage at diagnosis (7.1%) and one who relapsed (7.1%). The patients on modified PETHEMA had a significantly higher EFS (P = 0.012), lower frequency of sepsis during treatment (7.7% vs. 77.8%; P = 0.0015), and lower hospitalization cost (median US$ 4,700 vs. US$ 20,000; P < 0.0001) than those on in-house protocol.

CONCLUSION

Treatment with the less intensive protocol based on the PETHEMA LPA99 study of childhood APL successfully reduced chemotherapy toxicity and lowered hospitalization costs without increasing relapses. This led to decreases in treatment-related morbidity and the treatment abandonment rate, thus improving overall outcome.

Improved Outcome of Acute Promyelocytic Leukemia With High WBC Counts Over the Last 15 Years: The European APL Group Experience

Purpose

Acute promyelocytic leukemia (APL) with pretreatment WBC counts greater than 10,000/μL is still considered to carry a poorer prognosis than APL with WBC lower than 10,000/mL. We evaluated outcome improvement in such patients in recent years.

Patients and Methods

Nine hundred two patients with APL, including 204 patients and 68 patients with WBC counts more than 10,000/μL and more than 50,000/μL, respectively, were enrolled between 1993 and 2005 in two successive randomized trials of the European APL group (APL 93 and APL 2000) that tested, in particular, the modalities of combination of all-trans retinoic acid (ATRA) and chemotherapy, maintenance treatment, escalating doses of cytarabine, early administration of dexamethasone, and CNS prophylaxis.

Results

Between the APL 93 and 2000 trials, the complete response (CR) rate increased from 89.6% to 93%, and the 5-year cumulative incidence of relapse (CIR) decreased from 40% to 9.5% in patients with WBC counts of 10,000 to 50,000/μL. In patients with WBC counts more than 50,000/μL, the CR rate increased from 82% to 91%, and 5-year CIR decreased from 59% to 24%. Whereas in the APL 93 trial, increased WBC counts were significantly associated with higher CIR and shorter survival, this was not the case in the APL 2000 trial. In patients with increased WBC counts, enrollment onto the APL 2000 trial (v APL 93) and combined maintenance with ATRA and chemotherapy were associated with significantly lower CIR and better survival.

Conclusion

Outcome of APL with high WBC count has markedly improved over the years as a result of fewer early deaths and fewer relapses. Better initial supportive care and combined maintenance treatment have contributed to this improvement.

The race and dose of chemotherapy should be considered for optimizing maintenance therapy for acute promyelocytic leukemia

Although European conventional maintenance therapy for acute promyelocytic leukemia consisting of all-trans retinoic acid, 6-mercaptopurine, and methotrexate has been adopted in some trials, the adverse events of this therapy have not been described well. We describe adverse events of this therapy in detail and we find that the tolerance of maintenance therapy may depend on the race. Our results indicate that the race and dose intensity should be considered in addition to the number of consolidation courses and PML/RARA mRNA status in configuring the optimal regimen of maintenance therapy, because tolerability may depend much on the races and dose intensity.

Acute promyelocytic leukemia: from highly fatal to highly curable

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia. Morphologically, it is identified as the M3 subtype of acute myeloid leukemia by the French-American-British classification and cytogenetically is characterized by a balanced reciprocal translocation between chromosomes 15 and 17, which results in the fusion between promyelocytic leukemia (PML) gene and retinoic acid receptor alpha (RARalpha). It seems that the disease is the most malignant form of acute leukemia with a severe bleeding tendency and a fatal course of only weeks. Chemotherapy (CT; daunorubicin, idarubicin and cytosine arabinoside) was the front-line treatment of APL with a complete remission (CR) rate of 75% to 80% in newly diagnosed patients. Despite all these progresses, the median duration of remission ranged from 11 to 25 months and only 35% to 45% of the patients could be cured by CT. Since the introduction of all-trans retinoic acid (ATRA) in the treatment and optimization of the ATRA-based regimens, the CR rate was raised up to 90% to 95% and 5-year disease free survival (DFS) to 74%. The use of arsenic trioxide (ATO) since early 1990s further improved the clinical outcome of refractory or relapsed as well as newly diagnosed APL. In this article, we review the history of introduction of ATRA and ATO into clinical use and the mechanistic studies in understanding this model of cancer targeted therapy.

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.

Severe hemorrhagic complications during remission induction therapy for acute promyelocytic leukemia: incidence, risk factors, and influence on outcome

BACKGROUND

Even after the introduction of all-trans retinoic acid (ATRA), early hemorrhagic death remains a major cause of remission induction failure for acute promyelocytic leukemia (APL).

METHODS

To investigate severe hemorrhagic complications during remission induction therapy with respect to incidence, risk factors, and influence on outcome. Results were analyzed for 279 patients enrolled in the APL97 study conducted by the Japan Adult Leukemia Study Group (JALSG).

RESULTS

Severe hemorrhage occurred in 18 patients (6.5%). Although most of them were receiving frequent transfusions, the targeted levels of platelet counts (30 x 10(9)/L) and plasma fibrinogen (1.5 g/L) for this study were reached at the day of bleeding in only 71% and 40%, respectively. Nine of them succumbed to an early death, while the remaining nine patients eventually achieved complete remission (CR). The 5-yr event-free survival rate was 68.1% for those who did not suffer severe hemorrhage, and 31.1% for those who did (P < 0.0001). For patients who achieved CR, on the other hand, there was no difference in disease-free survival between patients with and without severe hemorrhage (P = 0.6043). Risk factor analysis identified three pretreatment variables associated with severe hemorrhage: initial fibrinogen level, white blood cell count, and performance status. Additionally, patients with severe hemorrhage were more easily prone to develop retinoic acid syndrome or pneumonia than patients without hemorrhage.

CONCLUSIONS

These results indicate that fatal hemorrhage represents a major obstacle in curing APL, and that patients with such high-risk features may benefit from more aggressive supportive care.

Current therapeutic strategies for acute myeloid leukaemia

Improvements in survival in adult acute myeloid leukaemia (AML) have yet to be gleaned from either refinements in the understanding of the pathophysiology of the disease or from the expanding pool of targeted therapies. Outcomes have remained particularly dismal in older patients. Ongoing and planned trials will assess the effects of drugs targeting biological pathways whose clinical importance may vary as a function of the unique genotype and phenotype of each case of AML. The success of these ventures will ultimately require well-designed clinical trials in subsets of patients with risk being dependent not only on age and cytogenetics, but on additional, increasingly quantifiable biological variables. Inhibitors of fms-like tyrosine kinase-3, farnesyl transferase, apoptotic and angiogenic pathways are being studied alone and in combination with chemotherapy. Biological therapies, including monoclonal antibodies, peptide vaccines and interleukin-2, are undergoing evaluation. The role of autologous as well as allogeneic myeloablative and reduced-intensity transplantation continues to be defined. Several potentially useful new cytotoxic agents are being introduced. Critically important to advancing the field in light of such an increasing number of choices is a reassessment of traditional phase II trial designs so that more efficient evaluation of new therapies may take place, even as well-designed phase III trials continue to be performed.