Complete Hematological Remission Rate Research Articles

Asciminib plus dasatinib and prednisone for Philadelphia chromosome–positive acute leukemia

AbstractDasatinib is an effective treatment for Philadelphia chromosome–positive (Ph+) acute leukemia, but some patients develop resistance. Combination treatment with dasatinib and asciminib, an allosteric inhibitor of BCR::ABL1, may deepen responses and prevent the emergence of dasatinib-resistant clones. In this phase 1 study (NCT03595017), 24 adults with Ph+ acute lymphoblastic leukemia (ALL; ALL, n = 22; p190, n = 16; p210, n = 6) and chronic myeloid leukemia in lymphoid blast crisis (n = 2) were treated with escalating daily doses of asciminib in combination with dasatinib 140 mg daily plus prednisone 60 mg/m2 daily to determine the maximum tolerated dose. After a 28-day induction, dasatinib and asciminib were continued indefinitely or until hematopoietic stem cell transplant. The median age was 64.5 years (range, 33-85; 50% aged ≥65 years). The recommended phase 2 dose of asciminib was 80 mg daily in combination with dasatinib and prednisone. The dose limiting toxicity at 160 mg daily was asymptomatic grade 3 pancreatic enzyme elevation without symptomatic pancreatitis. There were no vaso-occlusive events. Among patients with de novo ALL, the complete hematologic remission rates at days 28 and 84 were 84% and 100%, respectively. At day 84, 100% of patients achieved complete cytogenetic remission, 89% achieved measurable residual disease negativity (<0.01%) by multicolor flow cytometry, and 74% and 26% achieved BCR::ABL1 reverse transcription polymerase chain reaction <0.1% and <0.01%, respectively. Dual BCR::ABL1 inhibition with dasatinib and asciminib is safe with encouraging activity in patients with de novo Ph+ ALL. This trial was registered at www.clinicaltrials.gov as #NCT02081378.

Dose Reduced Chemotherapy in Sequence with Blinatumomab for Newly Diagnosed Older Patients with Ph/BCR::ABL Negative B-Precursor Adult Lymphoblastic Leukemia (ALL): Preliminary Results of the GMALL Bold Trial

Older patients (pts) with newly diagnosed ALL are ineligible for unmodified pediatric-based therapies. Although results are improved with age-adapted, dose-reduced regimens including MRD-based treatment modification, there is much space for further improvement.Therefore, the GMALL study group developed a trial to evaluate Blinatumomab, a CD19 directed bi-specific T-cell engager, in sequence with chemotherapy in this patient population with high medical need (NCT 03480438). Importantly, Blinatumomab replaced three cycles of standard consolidation chemotherapy.Pts aged 56 - 76 years (yrs) with CD19-positive, Ph-neg B-precursor ALL wereeligible. The primary endpoint was complete hematologic remission (CR) afterinduction (1 cycle chemo, 1 cycle Blinatumomab) and the key secondary endpoint was molecular response (table 1). The efficacy population included pts treated with dose reduced and shortened induction I (IP1) and Blinatumomab 1 or early death (ED). Induction was followed by 3 further Blinatumomab cycles alternating with age adapted consolidation cycles (HDMTX/ASP, HDAC, reinduction and maintenance) according to GMALL protocols for older pts (Gökbuget et al, ASH 2021). The median age was 66 (56-76) yrs. 21% had pro-B-ALL and 79% c/preB subtype. 40% had comorbidities according to the Charlson Score; most frequent were diabetes (13%) myocardial infarction (10%) or vascular diseases (10%). 50 pts were evaluable for IP1: 76% achieved CR/CRu and 2 pts (4%) died due to infections. 33% (N=11) had a molecular response and 18% MolCR (table 1). 47 pts were evaluable for the primary endpoint after Blinatumomab 1: CR/CRu was observed in 85%; 2 experienced ED (4%; those mentioned above; no additional ED). 88% of the CR pts had a molecular response (82% MolCR). The median follow-up is 757 (61-1584) days. Overall Survival (OS) after 1 and 3 yrs was 80% and 67% for the efficacy population (figure 1). The resp results for the total population were 82% and 65%. The 3y OS was 69% for c/pre-B-ALL and 58% for pro-B-ALL (p&amp;gt;.05). 3y OS was 81% for pts aged 55-65 yrs and 53% for those older than 65 yrs (p=.025). Only three pts received an allogeneic stem cell transplantation in CR1. 6 pts relapsed, 2 pt developed a secondary malignancy (Colon Ca, MDS) and 3 pts died in CR (1 HLH, 1 arterial disease, 1 Covid19). EFS was 60% at 3 yrs. We compared the results with those of the current GMALL standard therapy for older pts with B-precursor ALL (N=186) (Gökbuget et al, ASH 2022). Patient characteristics were similar. CR rates after induction were 85% vs 78% for BOLD vs standard (p&amp;gt;.05). Molecular CR rates in pts with hematologic CR were 82% vs 55% (p=.006). OS at 3 yrs was 67% and 49% (p=0.08) and Remission Duration (RD) was 83% vs 58% (p=0.055). Overall tolerability and efficacy of the regimen was very promising with a high hematologic and molecular response rate; mortality in induction and consolidation was low. In comparison with the current standard therapy the MRD response rates were significantly better. OS and RD was superior despite the omission of several chemotherapy cycles in contrast to other trials with unmodified chemotherapy but additional cycles of Blinatumomab. An ongoing randomized trial (NCT04994717) compares an even more dose reduced combination of Blina and chemotherapy with standard of care. This is an independent academic trial initiated by the GMALL Study Group which received free supply of Blinatumomab and financial support by Amgen.

Efficacy of a Second Allogeneic Hematopoietic Cell Transplant in Relapsed Acute Myeloid Leukemia: Results of a Systematic Review and Meta-Analysis

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only known treatment modality that can offer the possibility of cure for acute myeloid leukemia (AML). Unfortunately, relapse and disease progression still occur in more than one third of cases even when patients are allografted in complete hematologic remission (CR). Treatment of AML relapsing after a first allo-HCT is particularly challenging. A second allo-HCT is offered to patients considered fit for the procedure, but reported outcomes have been conflicting. To perform a systematic review and meta-analysis to assess the totality of evidence on the role of a second allo-HCT in patients with AML, we performed a comprehensive literature search using PUBMED/MEDLINE and EMBASE on August 25, 2021, and extracted clinical outcome data relating to benefits (CR, overall survival [OS], and progression-free/disease-free survival [PFS/DFS]) and harms (acute and chronic graft-versus-host disease, non-relapse mortality [NRM], and relapse). The search identified 821 studies. Only 20 studies (n = 2772 patients) met our inclusion criteria. A second allo-HCT resulted in pooled CR, OS, PFS/DFS, NRM and relapse rates of 67%, 34%, 30%, 27%, and 51%, respectively. OS was 2-fold higher when the second allo-HCT was performed in CR (38% versus 17%) and 3-fold higher in patients who had a later relapse from the first allo-HCT (34% versus 10%). There was no apparent difference in pooled OS (hazard ratio = 1.01; 95% confidence interval, 0.78-1.31; P = .94) whether the same original donor or a different one was used. Notwithstanding several limitations apart from the high heterogeneity among included studies, this analysis shows that a second allo-HCT is a reasonable treatment option for relapsed AML. The procedure appears to be more effective when performed in CR and in patients who had a later relapse from the first allo-HCT. The high pooled relapse rates exceeding 50%, even when receiving the second allo-HCT in CR is worrisome and emphasizes the need to incorporate new therapies whether as post-transplantation maintenance or consolidation to mitigate relapse risk. This analysis was limited to patients receiving a second allo-HCT for the sole purpose of treating AML relapse. Accordingly, we caution against extrapolating these findings to other indications such as treatment of graft failure, poor graft function, or mixed donor chimerism.

Clinical Effect of Imatinib, Nilotinib, and Dasatinib on Chronic Myeloid Leukemia in Chronic Phase

The study was conducted to explore the effect of imatinib, nilotinib, and dasatinib in the treatment of chronic myeloid leukemia (CML) patients. Around 66 patients with CML in chronic phase were selected, subsequently the patients were subdivided into 3 groups with 22 patients in each group: Group A were treated with imatinib; Group B were treated with nilotinib; and Group C were treated with dasatinib. The study showed that, at 18 months of treatment, compared with group A, the molecular biology remission rates of group B and group C were significantly higher, p&lt;0.05; at 6 months and 18 months of treatment, compared with group A, the complete cytogenetic remission rates of group B and group C were significantly higher, p&lt;0.05; and compared with group A, the incidences of vomiting, headache and edema in groups B and C were significantly lower, p&lt;0.05. However, no significant different p&gt;0.05 were observed in the complete hematologic remission rates, and the incidences of neutropenia and thrombocytopenia among the three groups. In summary, nilotinib and dasatinib are effective in the treatment of patients with CML in the chronic phase, which is significantly better than imatinib treatment.

Interferon-Alpha (IFN) Therapy Discontinuation Is Feasible in Myeloproliferative Neoplasm (MPN) Patients with Complete Hematological Remission

Background: Although patients with MPN may achieve complete hematological remission (CHR) with cytoreductive therapy (CRT), lifelong treatment represents a major burden for these chronically ill patients. IFN has emerged as a major MPN therapy thought to positively alter the natural history of MPN and appears to be the only drug that can provide long-term CHR after discontinuation in some patients (Hasselbalch HC et al., Seminars in Immunopathology, 2019). In this study, we aimed to identify clinical and molecular factors associated with long-term CHR after IFN treatment discontinuation and to compare clinical outcome of patients who discontinued therapy, to patients who continued IFN treatment despite achieving a CHR. Methods: All MPN patients followed between January 2000 and May 2020 in our institution who received at least 3 months of IFN were included. Logistic regression analysis was performed to identify variables associated with long-term CHR after discontinuation. Cumulative incidence of relapse was calculated from time of IFN discontinuation, considering death without relapse as a competitive event. Overall survival (OS) and thrombotic/hemorrhagic events free survival (EFS) curves were estimated using the Kaplan-Meier method and compared by cause-specific hazard Cox models. Results: 381 patients treated with IFN were included in the study. Median age at MPN diagnosis was 44 years [interquartile range: 33-54]. 171 had polycythemia vera (PV), 169 essential thrombocythemia (ET) and 34 primary myelofibrosis (PMF). JAK2V617F was the most frequent driver mutation (78.8% of patients), while CALR and MPL were mutated in 15.5%, and 2.9% of patients respectively. Median driver variant allele frequency (VAF) at time of IFN therapy initiation was 34% [12; 51]. Reasons to start IFN included age younger than 50 years in 44.9%, intolerance/resistance to previous therapies in 17.8% or pregnancy in 1.8% patients. CHR was achieved with IFN in 77.2% of patients. After a median follow-up of 72.4 months [28.4; 119.7] from IFN initiation, 131 patients were still on IFN treatment, while 250 patients had discontinued therapy. No significant difference was observed between continued and discontinued IFN patients in terms of MPN subtype, initial clinical, biological or molecular characteristics. Reasons for discontinuation were toxicity in 128 (50.4%), prolonged hematological CHR in 76 (29.9%), failure in 16 (6.3%) and other in 30 (11.8%) patients. At time of IFN discontinuation, 170 (66.9%) patients were in CHR and the median driver mutation VAF was 12% [3; 35]. Of note, IFN was re-introduced in 61 patients who lost CHR with a second CHR rate of 83.6%, arguing for the absence of development of IFN resistance in post-discontinuation relapses. In multivariate logistic regression analysis, stopping for prolonged CHR (OR 3.52, 95%CI [1.18; 10.56], p=0.024) was associated with a higher CHR without CRT rate, while VAF ≥ 10% at time of IFN discontinuation (OR 0.26, 95%CI [0.1; 0.65], p=0.004) was associated with lower long-term CHR without CRT. Accordingly, VAF ≥ 10% at time of IFN discontinuation (HR 3.06 [1.59; 5.90], p=0.001) was independently associated with a higher cumulative incidence of relapse after IFN discontinuation (Figure A). Driver VAF at IFN discontinuation time was available for 117 patients. 53 patients (45.3%) had a driver VAF &amp;lt; 10% at IFN discontinuation. Finally, we compared discontinued IFN patients who stopped IFN for CHR (n=76) to patients who obtained CHR and are still on IFN therapy (n=116). Hematological transformation could not be evaluated due to very low incidence of events: 2 patients from each group progressed to myelofibrosis while leukemic progression was only observed in 1 patient. Importantly, OS (HR 0.23, 95%CI [0.5; 1.14], p=0.07) and EFS (HR 0.53, 95%CI [0.19; 1.45], p=0.217) were not significantly different between patients who discontinued and those who continued IFN. Conclusion: Overall, our study demonstrates that IFN discontinuation represents a safe strategy in MPN patients who achieved CHR, and particularly in patients with a driver VAF lower than 10% at time of discontinuation. Importantly, relapsed patients did not develop IFN resistance. Our data contributes to set the frame for future clinical trials evaluating the possibility of IFN treatment holidays in good responding MPN patients. Disclosures Benajiba: Gilead Foundation: Research Funding. Kiladjian:Abbvie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; AOP Orphan: Membership on an entity's Board of Directors or advisory committees.

Analysis of clinical characteristics, treatment response rate and survival of 77 myelodysplastic syndrome patients with del (5q) syndrome

目的探讨符合WHO（2016）诊断分型标准的骨髓增生异常综合征（MDS）5q−综合征患者的临床特征、来那度胺（LEN）疗效和生存情况。方法回顾性分析2008年1月至2018年4月于中国医学科学院血液病医院就诊的77例符合WHO（2016）诊断分型标准的MDS 5q−综合征患者临床资料，比较单纯5q−与5q−伴1个非−7/7q−的其他染色体异常（ACA）患者临床特征、疗效及生存情况，并比较LEN与非LEN药物治疗的疗效与生存情况。结果77例患者中，单纯5q−者64例，5q−伴ACA者13例，确诊时5q−伴ACA患者的中位年龄显著低于单纯5q−患者[58（29~64）岁对63（31~82）岁，z=2.164，P=0.030]。5q−伴ACA患者CD41免疫组化染色小巨核细胞（直径≤40 µm）检出率（91.7%，11/12）显著高于单纯5q−患者（60.0%，33/55）（P=0.046）。可评估LEN疗效的29例患者中，单纯5q−患者（19例）与5q−伴ACA患者（10例）血液学总反应率（78.9%对80.0%）、血液学完全缓解（CR）率（57.9%对60.0%）、细胞遗传学反应（CyR）率[69.2%（9/13）对66.7%（4/6）]、完全细胞遗传学反应（CCyR）率[61.5%（8/13）对33.3%（2/6）]相当。单纯5q−与5q−伴ACA患者中位总生存（OS）时间差异无统计学意义（62个月对78个月，P=0.313）。29例LEN组患者的血液学总反应率（79.3%对36.0%）、CR率（58.6%对8.0%）、CyR率[68.4%（13/19）对11.1%（1/9）]、CCyR率[52.6%（10/19）对0（0/9）]均高于非LEN组患者（25例），但两组患者中位OS时间差异无统计学意义（78个月对62个月，P=0.297）。结论单纯5q−与5q−伴ACA患者临床特征大体相似，两组患者LEN疗效、中位OS时间无明显差异。LEN治疗5q−综合征患者的疗效肯定，优于非LEN药物。

Slit-Robo Pathway Is Clinically Relevant and May Represent a Potential Target in Acute Promyelocytic Leukemia

Slit-Robo Pathway Is Clinically Relevant and May Represent a Potential Target in Acute Promyelocytic Leukemia

NSD1 and NSD2 Transcriptional Levels Might Predict Clinical Outcome in AML Patients

Aims: The active methylation of histones plays an important role in regulation of gene expression. Nuclear SET Domain (NSD) Histone Lysine Methyltransferases family (KMT) is composed of three members: NSD1, 2 and 3 which regulates gene expression through methylation of H3K36. NSD2 overexpression, initially reported in multiple myeloma, was recently associate with EZH2 mRNA levels through interaction with H3K27me3 which suppresses the expression of miR-203, miR-26a and miR-31 leading to the up regulation of NSD2 mRNA levels. This correlation has been observed in various types of cancer, although there is no data in myeloid malignancies. Aim: To evaluate the gene expression profile of the NSD family in three de novo AML cohorts: one Brazilian cohort and two public databases addressing its applicability in prediction of treatment outcomes, retrospectively. Methods: As a learning set, samples from 146 subjects (age, 18-87y) were analyzed. Seventy (48%) patients were treated in a University Hospital that serves as reference for northeast of Brazil, while 76 patients were treated in a center of similar characteristics in the southeast of the country. The baseline features distribution was similar between centers. The treatment protocol was described elsewhere (Lima AS et al., Blood, 2015), but was based on anthracycline and cytarabine for induction and intermediate to high doses of cytarabine as consolidation. As controls, sixteen samples of CD34+ cells isolated from total bone marrow (BM) of healthy volunteers (age, 18-60y) were analyzed. The external validation cohort composed by 173 patients (age, 18-88y) were obtained from TCGA AML study available online on CBioPortal for Cancer Genomics (Gao et al. 2013). Patients were dichotomized into “low” and “high” NSD1, 2 and 3 expression groups based on survival receiver operating characteristic (ROC) curve and the C index analyses. To validate our data, NSD transcript levels from an independent cohort was used (525 patients from Amazonia! - NSD1 Probe #219084_at; NSD2 Probe #209052_s_at; NSD3 Probe #218173_s_at - and five normal CD34+ samples included in the same databank). The following parameters were used to evaluate treatment outcome: complete hematological remission (CHR); 5-year Disease-Free Survival (DFS) and 5-year Overall Survival (OS) rates. Results: The median age of the learning set was 46y with 70 males (48%). NSD1, 2 and 3 expression levels are lower in de novo AML samples compared to CD34+ cells (P<.001). These results were not validated in an Amazonia! cohort, which patients with AML had a higher-than-normal expression of NSD1 and 3 (P=.01). Expression of all NSD was closely correlated in the learning set cohort (r>0.96) albeit only NSD2 and 3 had a correlation in the validation cohort (r=0.6). Baseline characteristics (sex, age, leukocyte count, cytogenetic risk, FLT3 and NPM1 mutations)were similar between the cohort of patients with NSDs low and high expression, except for higher blast count in BM, but not in peripheral blood, in high expression group for NSD1 and 2 (P=.021 and P=.033, respectively). Overall, 78/146 (57%) patients achieved CHR. Patients with a high NSD1 expression had a lower CHR rate (44%) compared with those a low expression (56%) (OR: 0.5; 95%CI: 0.2-0.9; P=.04). With a median follow up of 21 months (1-61 months) the estimated 5y DFS rate was 49% (95%CI: 30-65%). The group with high NSD1 expression presented a lower 5y DFS rate (13%; 95%CI: 1-42%) than those with low NSD1 expression (72%; 95%CI: 47-87%) (P=.003). This result was consistent with the multivariable proportional hazards analysis (HR: 7.3; 95%CI: 1.3-38; P=.02). The estimated 5y OS rate was 24% (95%CI: 14-35%) which patients with high NSD1 expression exhibiting lower 5y OS rate (13%; 95%CI: 4-29%). The median age of the external validation cohort was 58y with 107 males (62%). Only NSD2 levels had a association with higher diagnosis age (P=.008). With a median follow up of 40 months (1-118 months) the NSD expression may predict only a higher 5y OS rate in patients with high NSD2 expression (30%; 95%CI: 26-49%) retained the result in a multivariable model (HR: 0.53; 95%CI: 0.3-0.9; P=.02). Conclusions: In summary, NSD1 and 2 transcript levels were independent factors associated with treatment outcomes in two AML cohorts treated with standard protocols based on anthracyclines and cytarabine. DisclosuresNo relevant conflicts of interest to declare.

The Use of Cyclosporine in Association with Chemotherapy As Induction Treatment in Patients with Acute Myeloid Leukemia (AML) and High Rhodamine Efflux at Diagnosis Results in Higher Complete Hematological Remission Rates, but Does Not Prolong Overall Survival

The overexpression of P-glycoprotein (Pgp) in leukemic blasts of Acute Myeloid Leukemia (AML) is associated with lower complete remission (CR) rates and shorter disease-free (DFS) and overall survival (OS). Cyclosporine A (CSA) is a competitive inhibitor of Pgp capable of reduce the P-gp mediated drug efflux. List et al. reported that CSA addition to treatment with cytarabine and daunorubicine reduced the resistance to induction treatment (IT) and prolonged DFS and OS. The effect was greater in AML patients with higher Pgp expression (Blood 2001; vol 98, n 12: 3212-20). Based on this study, we tested the effect of the association of CSA to IT in cases with high Pgp expression, which was established using the Rhodamine effux test as previously described (Pétriz, J. and García-López, J. Leukemia 1997; vol 11: 1124-30). The cut off value of the mean fluorescence intensity adopted to define high P-gp expression was ≥ 1.10. A total of 21 high P-gp AML patients were randomized in two groups: 1. Daunorubicin (DNR) 60mg/m² in continuous infusion -CI- 3x+Cytarabine 100 mg/m² CI 7x + CSA 16mg/m² CI 3x; (CSA group) and 2. DNR 60mg/m² CI 3x + Cytarabine 100 mg/m² CI 7x (Conventional IT group). Patients who did not achieve Complete Hematological Remission (CHR) in the first cycle of chemotherapy received a second course. The 2 groups did not differ regarding age (mean ± S.D.: 44.5 ± 11.9 vs. 48.5 ± 15.2 years in CSA and conventional IT group, respectively), leukocyte counts at diagnosis (44,200 ± 56,100 vs. 21,540 ± 20,200/µl), frequency of de Novo AML (81.8 vs. 80%) and of Core Binding Factor Leukemia cases (18.2 vs. 10%). The median follow up among survivors was of 6.2 years. The mean serum levels of CSA at 24 hours after infusion was of 1,157 ng/mL (range: 4 - 1,600ng/mL), which was similar to that reported by List et al. The CHR rate after the first cycle of induction was higher in the group using CSA (63.6% vs. 30%; p = 0.09) but the DFS (2.05 years vs. not reached; p= 0.27) and OS (4.08 vs. 21.12 months; p = 0.19) were higher in conventional IT group. These results may reflect the effect of the second course of induction in patients who failed to achieve CHR (CHR after second IT: 0% vs. 33.3%, p=0.34, in CSA and conventional IT group, respectively) and higher relapse rate in CSA group (42.8% vs. 33.3%, p=0.78). Furthermore, there was a lower frequency of induction deaths (18.2% vs. 9%; p = 0.59) and of hyperbilirubinemia (bilirubin > 1,5x the upper limit of normality) in the Conventional IT group (6 vs. 0 patients; p = 0.02). There were no cases of acute cardiac toxicity. The study was interrupted due to the cost of CSA and the lack of significant improvement in the outcomes. In conclusion, despite the higher rate of CR after one cycle of chemotherapy, there was not improvement in long term survival of AML patients with high Pgp expression treated with CSA in combination with anthracyclines and cytarabine. DisclosuresNo relevant conflicts of interest to declare.

Prognostic Impact Of MLL5 transcript Levels On Outcome Of Patients With Acute Promyelocytic Leukemia Treated With All-Trans Retinoic Acid and Anthracycline-Based Chemotherapy: An International Consortium On Acute Promyelocytic Leukemia Study

BackgroundThe MLL5 gene encodes a histone methyltransferase implicated in positive control of several genes related to hematopoiesis. Its close relationship with retinoic acid–induced granulopoiesis suggests that the deregulated expression of MLL5 might lead acute promyelocytic leukemia (APL) blasts to become less susceptible to differentiation-inducing ATRA effects. Here, we retrospectively determined the MLL5 transcript levels in samples from APL patients enrolled in the International Consortium on Acute Promyelocytic Leukemia (IC-APL) trial and analyzed its relationship with clinical and laboratory features, hematologic recovery, relapse, and survival. The results of the IC-APL have been previously reported (Blood 2013, 121(11) pp: 1935). In brief, complete hematological remission (CR) was achieved by 153/180 patients enrolled in Brazil, Mexico, Chile and Uruguay and after a median follow up of 28 months, the 2-year cumulative incidence of relapse (CIR), overall survival (OS) and disease-free survival (DFS) were 4.5%, 80% and 91%, respectively.Design and MethodsOne hundred and twenty-one APL patients (age, 15-73y) from seven different Brazilian institutions and treated according to the IC-APL protocol were included. The treatment schedule was identical to that adopted in the PETHEMA/HOVON LPA2005 trial, except for the replacement of idarubicin by daunorubicin. ATRA treatment was initiated immediately in all cases in which the diagnosis of APL was suspected based on morphology. As normal controls, total bone marrow (BM, n=8) and peripheral blood (PB, n=101) cells from healthy donors (age, 18-60y) were collected and mononuclear cells were isolated by Ficoll-Hypaque density gradient centrifugation. Additionally, 28 CBF-leukemia samples were included. Gene expression profile was analyzed by real-time quantitative PCR using the ABL FusionQuant Standard Kit as an endogenous control. Based on the continuous distribution of MLL5/ABL expression on APL samples (Figure 1), we adopted the median value of MLL5/ABL expression as cut-off to dichotomize APL patients in “low” and “high” MLL5 transcript levels.ResultsMLL5 expression was not different between APL, CBF-leukemia and healthy donors samples (Figure 1; P=0.19). There was no relevant difference between APL patients with low (n=62) and high (n=59) MLL5 transcript levels with respect to clinical and laboratory features, although high MLL5 transcript levels were more likely to be present in female gender (P=0.029). Overall, 102 (84%) achieved CR. Patients with low MLL5 transcript levels had significantly lower CR rate than patients with high MLL5 transcript levels (74% vs 95%; P=0.002). Twelve patients (10%) experienced early mortality (i.e., death during induction therapy) due to hemorrhage (n=6; 50%), disease progression (n=1; 8.3%), thrombosis (n=1; 8.3%), therapy-related infection (n=3; 25%) and differentiation syndrome (n=1; 8.3%); MLL5 transcript levels had no impact on early mortality (P=0.155). With a follow-up of 33 months among survivors (range, 1-72 months), patients with low MLL5 transcript levels had significantly lower 2-year OS (P=0.005) and 2-year DFS rate (P=0.037) than patients with high MLL5 transcript levels. Up to January 2013, a total of six relapses (5%) had been recorded. The 2-year CIR among patients with low and high MLL5 transcript levels was 14% (95%CI: 5% to 27%) and 2% (95%CI: 0.1% to 11%), respectively (P=0.04). We have further evaluated the prognostic impact of MLL5 transcript levels in those patients who remain alive after induction therapy (107 patients). Low MLL5 transcript levels were predictive of lower CR rate (P=0.042) and 2-year OS rate (P=0.009), but had no impact on DFS (P=0.106).ConclusionOur results show that MLL5 transcript levels may predict lower remission rate, short survival and higher risk of relapse in APL patients treated with ATRA and anthracycline-based chemotherapy. This is the first report describing the MLL5 expression as a prognostic factor in APL; nevertheless, our results should be confirmed in an independent cohort. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Minimal residual disease in acute myeloid leukemia: coming of age

Abstract The achievement of complete hematologic remission (CR) is a prerequisite for cure in acute myeloid leukemia (AML). The conventional definition of CR, based on the morphologic recognition of ≤ 5% of leukemic blasts in the BM, does not provide sufficient insight into the quality of the response. Despite CR rates of 50%-80% (depending on age), the majority of patients with AML relapse within 3-5 years from diagnosis. Therefore, there is great need of more sensitive prognostic factors that can predict relapse. Minimal residual disease (MRD), defined as any measurable disease or leukemia detectable above a certain threshold (defined by the methodology applied), predicts failure to maintain a morphologic CR and affects survival negatively. AML is lagging behind acute lymphoblastic leukemia with respect to the implementation of MRD criteria for guidance during therapy. AML is particularly disadvantaged compared with acute lymphoblastic leukemia in that approximately half of AML patients lack a molecular target suitable for MRD monitoring. The detection of altered antigen (Ag) expression by leukemic myeloblasts is a valid alternative to DNA- or RNA-based MRD assays. Although associated with presenting prognostic factors (eg, cytogenetics and genotype), MRD represents the collective end result of all of the cellular mechanisms that determine a patient's response to a given therapy. Therefore, MRD has 2 potential roles in AML treatment: (1) as a posttherapy prognosticator used to assign patients to optimal postinduction/consolidation therapy, and (2) as an early surrogate end point for the evaluation of therapy efficacy.

Treating Ph+ Acute Lymphoblastic Leukemia (ALL) in the Elderly: The Sequence of Two Tyrosine Kinase Inhibitors (TKI) (Nilotinib and Imatinib) Does Not Prevent Mutations and Relapse.

AbstractAbstract 2601▪▪This icon denotes a clinically relevant abstract Background:Tyrosine Kinase Inhibitors (TKI) have been shown to be very effective for the treatment of Acute Lymphoblastic Leukemia (ALL), with a Complete Hematologic Remission (CHR) rate close to 100%, and a high rate of Complete Cytogenetic and Molecular responses (CCgR and CMR). However, when they are used alone, as single agents, most patients relapse, so that they are currently used in combination with chemotherapy and as a preparation to allogeneic stem cell transplantation (SCT). Since Ph+ ALL is more frequent in the elderly, many patients cannot tolerate intensive chemotherapy and are not eligible for SCT. We have explored if the administration of two TKIs, Nilotinib (NIL) and Imatinib (IM) can improve the results without increasing the toxicity. Aims:To evaluate the response and the outcome of Ph+ ALL patients treated with the sequential administration of NIL and IM, to investigate the type and number of BCR-ABL kinase domain mutations developing during and after the study. Methods:We have designed a study (ClinicalTrials.gov. NCT01025505) in which patients more than 60 years old or unfit for intensive chemotherapy and SCT where treated with two TKIs, NIL 400 mg twice daily, and IM 300 mg twice daily, alternating for 6 weeks for a minimum of 24 weeks (study core) and indefinitely in case of response. The 6-weeks rotation schedule was respected, irrespectively of temporary discontinuations. The primary end-point was the rate of Disease Free Survival (DFS) at 24 weeks (4 courses of treatment); the secondary end points included the evaluation of CHR, CCgR and CMR rates. Mutation analysis was performed by nested RT-PCR amplification of the ABL kinase domain of the BCR-ABL transcript (codons 206 through 421). Amplified products were screened by denaturing-high performance liquid chromatography (D-HPLC). Samples scored positive for the presence of sequence variations were then subjected to direct automatic sequencing to characterize the mutation. Results:39 patients have been enrolled in 15 Italian hematologic Centers (median age 66 years, range 28–84). Among these, 8 patients were unfit for standard chemotherapy or SCT (median age 50 years, range 28–59). 27 patients were p190, 5 were p210 and 7 were p190/p210. After 6 weeks of treatment, 36 patients were evaluable for response: 34 were in CHR (94%) and 2 in PHR (6%). 23 patients have already completed the study core (24 weeks), 87% were in CHR and 17 are currently continuing therapy in the protocol extension phase.Thus, the OS at 1 year is 79%, and 64% at 2 years. Overall, 1 patient was primarily resistant and 13 patients have relapsed, with a median time to relapse of 7.6 months (range 0.8–16.1 months), for a DFS of 51.3% at 12 months (Figure 1). Mutations detected were T315I in 2 cases, Y253H in 3 cases, T315I and Y253H in 1 case, E255K in 1 case, T315I and E255K in 1 case, E255V and Y253H in 1 case. Two patients were WT.A detailed kinetics of Molecular responses is shown in Table 1. Data on mutational analysis are reported in Table 2. Further details about Cytogenetic and Molecular responses, and about Adverse Events will be provided on site. Conclusions:In this small cohort of Ph+ ALL elderly/unfit patients, the rates of relapse and progression were not likely to be different from the rates observed with Imatinib alone (Vignetti et al, Blood 2007, May 1;109(9):3676-8) and Dasatinib alone (Foà, Blood 2011, Dec 15;118(25):6521-8).It's important to notice that the mutations that occurred at the time of relapse were sensitive to other TKIs (Dasatinib and Ponatinib). Acknowledgments:COFIN, Bologna University, BolognAIL, PRIN, Fondazione del Monte di Bologna e Ravenna, INPDAP.Table 1Kinetics of Molecular responsenUndetectable (<0.0001)Total DetectableBCR-ABL <0.001BCR-ABL >0.1baseline3600036week 63137813week 123029127week 18222884week 24182772Table 2Mutational analysis was performed in 11/14 patients who failedPtsMutationTime to relapse (months)006001y253h, e255v5.5006012t315i, y253h20.1006018e255k, t315i3006020y253h8.8006026e255k7.3008007t315i2.5008015y253h14.5012035wt3.8042004wt10.1043009y253h17.4043030t315i7.3 [Display omitted] Disclosures:Pizzolo:Hoffmann-La Roche: Consultancy, Honoraria. Luppi:CELGENE CORPORATION: Research Funding. Vallisa:CELGENE CORPORATION: Research Funding. Martinelli:NOVARTIS: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; PFIZER: Consultancy; ARIAD: Consultancy. Baccarani:ARIAD, Novartis, Bristol Myers-Squibb, and Pfizer: Consultancy, Honoraria, Speakers Bureau.

1105 - Management of Pediatric Chronic Myeloid Leukemia: Experience from Eastern India

ABSTRACT Imatinib inhibits constitutively active BCR-ABL tyrosine kinase of chronic myeloid leukemia (CML). It is a novel molecule, which inhibits the protein product of this fusion gene and hence has been used in the treatment of CML. In a long term -term study it was found superior to interferon alfa plus cytarabine for newly diagnosed CML in the chronic phase. However, till date there is no major study to evaluate Eastern Indian patients with CML treated with imatinib mesylate. The present study evaluates 138 patients with CML treated with imatinib mesylate. Of these, 33 patients had to be excluded due to various reasons of noncompliance, death and not being fit to receive the drug. Among rest 105 patients, 95 was in chronic phase, 7 in accelerated phase and 3 patients had blast crisis at the time of presentation. Among 105 patients, 45 patients received either interferon alpha or hydroxyurea and other 60 patients were previously untreated. Complete hematological remission rate and major cytogenetic response (CGR) rates were 90% and 50%, respectively after 1 year of treatment. Complete molecular remission rate was 35% after 1 year of treatment. The number of imatinib resistant patients is 8, about 7.6 % of total included patients. The disease free and overall survival at 51 months are 75.5 and 81.5% respectively. Oedema, diarrhoea, abdominal pain, dermatitis, mucositis, neutropenia and thrombocytopenia were some of the major toxicities. After 51 months of follow-up, continuous treatment of chronic-phase CML with imatinib as initial therapy was found to be safe and able to induce durable responses in a high proportion of patients. Thus it can be concluded that imatinib therapy in pediatric patients can replace bone marrow transplantation. Disclosure All authors have declared no conflicts of interest.

Response to Imatinib mesylate in chronic myeloid leukemia patients with variant BCR-ABL fusion transcripts

Chronic myeloid leukemia patients with different BCR-ABL transcripts might respond differently to Imatinib mesylate. This prompted us to study BCR-ABL transcripts in chronic myeloid leukemia (CML) patients and their correlation with response to Imatinib. Eighty-seven chronic phase CML patients (median age, 35 years; range, 13-62 years; M/F, 59:28) were included in this study; 57 patients had received interferon-alpha and/or hydroxyurea, and 30 were previously untreated. All patients received Imatinib mesylate (Gleevec) 400 mg daily. Complete hematological remission rate and major cytogenetic response (CGR) rates were 99% and 72%, respectively. B3a2 transcript was present in 53% of patients, b2a2 in 39%, and both transcripts in 8% of patients. Twenty of 34(59%) patients with b2a2 type achieved complete CGR compared to 15 of 53 (28%) patients with b3a2, p = 0.04. Among 24 patients with minor or no CGR, six (25%) had b2a2 compared to 18 (75%) b3a2 type, p = 0.04. Expression of BCR-ABL/ABL% was higher in b3a2 patients compared to b2a2, p = 0.120. Pre-treatment characteristics-mean spleen size (6.6 vs. 6.4 cm, p = 0.868), mean hemoglobin (G/dl; 12.0 vs. 11.8, p = 0.690), mean WBC count (83 x 10(9) vs. 77 x 10(9)/L, p = 0.923), and mean platelets counts (360x10(9) vs. 340 x 10(9)/L, p = 0.712)-were not significantly different in the b3a2 vs. b2a2 transcripts groups. Our preliminary findings suggest that CML patients with b2a2 BCR-ABL transcript might have higher CGRs to Imatinib mesylate (Gleevec).

Sequential Homoharringtonine and Interferon-α in the Treatment of Early Chronic Phase Chronic Myelogenous Leukemia

AbstractHomoharringtonine (HHT) is a novel plant alkaloid that produced a complete hematologic remission (CHR) in 72% of patients with late chronic phase chronic myelogenous leukemia (CML). Cytogenetic (CG) remissions were noted in 31%. In this study, six courses of HHT were administered to 90 patients with early chronic phase CML (< 1 year from diagnosis). Patients then received interferon-α (IFN-α) with a target dose of 5 MU/m2 daily. Results were compared with those in a prior group of patients treated with IFN-α–based therapy between 1982 and 1990. Ninety-two percent of patients achieved CHR with HHT; CG responses were observed in 60% and were major in 27%. Both CHR and CG response rates were significantly higher than those seen in historical control patients after 6 months of IFN-α therapy. After receiving HHT, patients required lower doses of IFN-α to maintain a CHR. The median dose delivered was 2.4 MU/m2. This reduction in IFN-α dose was associated with a lower incidence of myalgia and gastrointestinal (GI) disturbances than that seen in patients treated at the 5 MU/m2 dose. Overall, CG responses were seen in 66% of the patients who received HHT and IFN-α compared with 61% of the historical control patients. HHT is a very effective treatment of early chronic phase CML, and ongoing trials are investigating the simultaneous administration of HHT and IFN-α, as well as that of HHT and low-dose cytosine arabinoside in patients failing IFN-α therapy.

Sequential Homoharringtonine and Interferon- in the Treatment of Early Chronic Phase Chronic Myelogenous Leukemia

Homoharringtonine (HHT) is a novel plant alkaloid that produced a complete hematologic remission (CHR) in 72% of patients with late chronic phase chronic myelogenous leukemia (CML). Cytogenetic (CG) remissions were noted in 31%. In this study, six courses of HHT were administered to 90 patients with early chronic phase CML (&lt; 1 year from diagnosis). Patients then received interferon- (IFN-) with a target dose of 5 MU/m2 daily. Results were compared with those in a prior group of patients treated with IFN-–based therapy between 1982 and 1990. Ninety-two percent of patients achieved CHR with HHT; CG responses were observed in 60% and were major in 27%. Both CHR and CG response rates were significantly higher than those seen in historical control patients after 6 months of IFN- therapy. After receiving HHT, patients required lower doses of IFN- to maintain a CHR. The median dose delivered was 2.4 MU/m2. This reduction in IFN- dose was associated with a lower incidence of myalgia and gastrointestinal (GI) disturbances than that seen in patients treated at the 5 MU/m2 dose. Overall, CG responses were seen in 66% of the patients who received HHT and IFN- compared with 61% of the historical control patients. HHT is a very effective treatment of early chronic phase CML, and ongoing trials are investigating the simultaneous administration of HHT and IFN-, as well as that of HHT and low-dose cytosine arabinoside in patients failing IFN- therapy.