Morphologic Complete Remission Research Articles

Vincristine Sulfate Liposome Injection (VSLI, Marqibo®) in Combination with UK ALL-R3 Induction Chemotherapy for Children, Adolescents and Young Adults with Relapsed Acute Lymphoblastic Leukemia (ALL): A Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) Consortium Trial

Introduction: Vincristine intensification has the potential to improve outcomes in ALL, but severe neurotoxicity has prohibited escalation beyond standard capped doses. Vincristine sulfate liposome injection, VSLI (Marqibo®) is a liposomal formulation of aqueous vincristine that optimizes pharmacokinetics, prolongs circulating half-life, increases tissue penetration, and may be better tolerated than standard vincristine. VSLI received accelerated FDA approval for adults with relapsed/refractory (r/r) ALL, at a dose of 2.25 mg/m 2/dose without a dose cap. A phase I trial of VSLI in children and young adults with r/r ALL demonstrated safety, tolerability, and evidence for single-agent activity (Shah NN, et al. Pediatric Blood Cancer, 2016). Studies of VSLI with combination chemotherapy in children have not been conducted. With emerging data supporting improved outcomes for patients (pts) with r/r ALL who proceed to immunotherapy with low-burden disease, identifying safe and effective reinduction regimens to reduce disease burden remains a priority.Methods: This multicenter pilot study conducted through the TACL consortium was designed to assess safety and feasibility of VSLI as replacement for standard vincristine with combination chemotherapy for individuals between the ages of 2-21 years with r/r ALL. Two dose levels of VSLI were utilized without a dose cap: Dose level 1 (DL1) 1.5 mg/m 2/dose; and Dose level 2 (DL2) 2.0 mg/m 2/dose. Treatment success was determined by both 1) the absence of a dose-limiting toxicity (DLT) (as defined by any > Grade 3 regimen related non-hematologic toxicity which precluded completion of the pre-specified treatment course or from proceeding to subsequent therapy within 7 weeks) and 2) completion of the prescribed treatment regimen. Adverse event grading was based on CTCAE v4.03. Bone marrow aspirate was used for standard morphologic assessment of response with central flow cytometric analysis for minimal residual disease (MRD) determination with a cut-off of <0.01% of mononuclear cells considered as MRD negative. This analysis reports the toxicities and feasibilities for Cohort A which constituted the 4-drug UK ALL-R3 induction regimen consisting of VSLI, dexamethasone, mitoxantrone, and asparaginase (pegaspargase or Erwinia).Results: A total of 10 pts with r/r B-ALL, median age 13.4 (range 5.0-17.3 years) were treated on Cohort A. Pts were heavily pre-treated, with 3 having relapsed after prior allogeneic stem cell transplantation; 8 of 10 had an M3 marrow (>/= 25% blasts). The first 4 pts were treated at DL1. All 4 were evaluable for toxicity and response and met the criteria for treatment success, facilitating dose escalation to DL2. At DL2, 4 pts were treated, with 2 experiencing DLT, including one grade (Gr) 5 event (Table 1). Two additional pts were subsequently treated at DL1 and achieved treatment success, confirming safety and feasibility of DL1 with a VSLI dose of 1.5 mg/m 2 in combination with UK ALL-R3 4-drug induction. Nine of 10 (90%) pts achieved a morphologic complete remission (CR), 5 of which were MRD negative. The median VSLI dose administered at DL1 was 2.3 mg (range, 1.8-3.2 mg) and at DL2 was 2.2 mg (range, 1.5-3.3 mg) demonstrating the feasibility of dosing beyond the standard vincristine dose-cap of 2 mg. Transient aspartate aminotransferase (AST) and alanine aminotransferase (ALT) elevations were seen in 8 pts, 6 of whom had a grade 1-2 toxicity. Gr 3 hepatic toxicities were seen in 3 pts: 1 each with ALT elevation and hyperbilirubinemia; ALT and AST elevation; gamma-glutamyl transferase elevation. Toxicities were generally consistent with the UK ALL-R3 regimen.Conclusions: In children with r/r ALL, the combination of UK ALL-R3 with VSLI was highly effective with an acceptable safety profile. DL1 (1.5 mg/m 2/dose) was found to be the maximum tolerated dose in combination with this intensive re-induction regimen. The trial continues to enroll at DL1 in the expansion phase to obtain additional safety and response data with this 4-drug regimen. Additionally, 2 cohorts have been added to gain further experience with VSLI in combination with 3-drug induction (Cohort B: UK ALL-R3 without mitoxantrone) and with ALL maintenance chemotherapy (Cohort C: dexamethasone, methotrexate, mercaptopurine). VSLI has potential as a vincristine dose-intensification strategy in combination with reinduction chemotherapy for r/r ALL in pediatric patients. [Display omitted] DisclosuresHermiston: Novartis: Consultancy; Sobi: Consultancy. Whitlock: Amgen; Jazz Pharmaceuticals: Honoraria; Novartis: Research Funding; Sobi Pharmaceuticals: Consultancy. Silverman: Takeda, Servier, Syndax, Jazz Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Wayne: Spectrum/Acrotech: Research Funding; KITE/Gilead: Research Funding.

Peripheral Blood Complete Remission Provides Added Value to the Classical Definition of Morphologic Complete Remission - a Prospective Cohort Study of 1441 Patients with MDS, CMML and AML Treated within the Austrian Azacitidine Registry

Peripheral Blood Complete Remission Provides Added Value to the Classical Definition of Morphologic Complete Remission - a Prospective Cohort Study of 1441 Patients with MDS, CMML and AML Treated within the Austrian Azacitidine Registry

Acute Myeloid Leukemia Patients in Complete Remission with Positive Measurable Residual Disease Prior to Allogeneic Transplant Have Worse Outcomes, Similar to Active Disease Regardless of Conditioning Regimen Intensity and Post-Transplant Cyclophosphamide Administration

IntroductionAllogenic hematopoietic cell transplant (HCT) for acute myeloid leukemia (AML) is a curative option in patients with intermediate/high risk disease who achieve morphologic complete remission (CR) after induction chemotherapy. Patients in CR but with positive measurable residual disease (pMRD) prior to HCT had high relapse risk(RR) (67% vs 65%) and low 3 year overall survival (OS) (26% vs 23%),similar to those with active disease in a single institution study (Araki et.al; Volume 34, Feb 1,2016, JCO). However, this study included only patients who received myeloablative conditioning (MAC) and included both peripheral blood and marrow grafts. A single institution retrospective study showed that use of MAC compared to reduced intensity conditioning (RIC) improved 3 year RR(19% v 67%; P < .001) and OS( 61% v 43%; P = .02) in patients with pMRD/CR(determined by molecular analysis of limited gene mutational panel)(Hourigan et.al. Volume 38, April 20,2020, JCO). We analyzed a cohort of AML patients that underwent either MAC or RIC followed by peripheral blood stem cell grafts and post-transplant cyclophosphamide (PTCy) based GVHD prevention regimen at our institution to determine the effect of pMRD on transplant outcomes.Methods:To evaluate the impact of pMRD on transplant outcomes, we analyzed AML patients who underwent HCT at Levine Cancer Institute between June 2014 and April 2020 with MRD testing performed within 1 month prior to HCT. MRD testing was performed at University of Washington by using multiparametric flow cytometry (MPC). The overall sensitivity of the assay is conservatively estimated as 0.1%. In our institution, all patients received MAC (Bu/Flu) or RIC (Bu/Flu or Flu/Cy/TBI) regimens followed by peripheral blood stem cell grafts and identical PTCy-based GVHD prophylaxis regimens that included tacrolimus and mycophenolate. Patient and transplant related characteristics were presented via descriptive statistics. Corresponding P-values were determined using Fisher's exact test for categorical variables and nonparametric Mann-Whitney U test for continuous variables. Relapse-free survival (RFS) and OS were estimated using the Kaplan Meier method. All statistical tests were two sided, and a P-value < 0.05 was considered statistically significant.ResultsFrom June 2014 to April 2020, 105 patients with AML underwent HCT. Eighty-three patients with MRD results were included in the final analysis - 52 (63%) with negative MRD (nMRD)/CR, 16 (19%) with pMRD/ CR and 15 (18%) with active disease (no CR). Baseline characteristics were similar except for presence of significantly greater number of high risk patients, based on ASTCT disease classification in the active disease group compared to pMRD/CR and nMRD/CR cohorts( 87% vs 19% vs 0%, P =< 0.001). Median follow up for the entire cohort was 32.7 months. RFS was superior in patients with nMRD/ CR compared to pMRD/ CR or active disease (56.4% vs 19.4% vs 35%, P= 0.005). In addition, OS was superior in nMRD/ CR compared to pMRD/CR or active disease (56.7% vs 35.2% vs 40%, P= 0.014). The use of MAC compared to RIC did not improve RFS (0% vs 32%, P= 0.018) and OS (0% vs 44%, P= 0.071) in pMRD/CR cohort. The use of MAC or RIC did not significantly impact RFS (69% vs 52%, P=0.729) or OS (61% vs 53%, P=0.739) in nMRD/CR patients.Conclusion:Our study validates the previous data that prognosis of patients with pMRD/CR (determined by MPC) prior to HCT is not significantly better than those having active disease. The outcomes were poor regardless of conditioning regimen intensity and PTCy based GVHD prophylaxis used at our institution. These patients might benefit from additional chemotherapy or targeted treatments to achieve nMRD prior to HCT and/or maintenance therapy post HCT. Patients with nMRD/CR disease had similar outcomes with MAC or RIC. This finding suggests that less aggressive conditioning regimens incorporating PTCy could be considered in a subset of patients with nMRD/CR, thereby sparing them from complications associated with MAC. Prospective trials are needed to further study these findings. [Display omitted] DisclosuresCopelan: Amgen: Consultancy. Grunwald: Astellas: Consultancy; Karius: Consultancy; PER: Other; Gilead: Consultancy; Incyte: Consultancy, Research Funding; Amgen: Consultancy; PRIME: Other; Daiichi Sankyo: Consultancy; Bristol Myers Squibb: Consultancy; AbbVie: Consultancy; Trovagene: Consultancy; Stemline: Consultancy; Pfizer: Consultancy; Janssen: Research Funding; Blueprint Medicines: Consultancy; Sierra Oncology: Consultancy; Med Learning Group: Other; Cardinal Health: Consultancy; MDEdge: Other; Agios: Consultancy.

Real-World Outcomes for Pediatric and Young Adult Patients with Relapsed or Refractory (R/R) B-Cell Acute Lymphoblastic Leukemia (ALL) Treated with Tisagenlecleucel: Update from the Center for International Blood and Marrow Transplant Research (CIBMTR) Registry

Real-World Outcomes for Pediatric and Young Adult Patients with Relapsed or Refractory (R/R) B-Cell Acute Lymphoblastic Leukemia (ALL) Treated with Tisagenlecleucel: Update from the Center for International Blood and Marrow Transplant Research (CIBMTR) Registry

CPX-351 induces remission in newly diagnosed pediatric secondary myeloid malignancies

AbstractSecondary myelodysplastic syndromes and acute myeloid leukemia (sMDS/AML) are rare in children and adolescents and have a dismal prognosis. The mainstay therapy is hematopoietic cell transplantation (HCT), but there has been no innovation in cytoreductive regimens. CP X-351, a fixed 5:1 molar ratio of liposomal cytarabine to daunorubicin, has shown favorable safety and efficacy in elderly individuals with secondary AML and children with relapsed de novo AML. We report the outcomes of 7 young patients (6 with newly diagnosed sMDS/AML and 1 with primary MDS/AML) uniformly treated with CP X-351. Five patients had previously received chemotherapy for osteosarcoma, Ewing sarcoma, neuroblastoma, or T-cell acute lymphoblastic leukemia; 1 had predisposing genomic instability disorder (Cornelia de Lange syndrome) and 1 had MDS-related AML and multiorgan failure. The median age at diagnosis of myeloid malignancy was 17 years (range, 13-23 years). Patients received 1 to 3 cycles of CP X-351 (cytarabine 100 mg/m2 plus daunorubicin 44 mg/m2) on days 1, 3, and 5, resulting in complete morphologic remission without overt toxicity or treatment-related mortality. This approach allowed for adding an FLT3 inhibitor as individualized therapy in 1 patient. Six patients were alive and leukemia-free at 0.5 to 3.3 years after HCT. One patient died as a result of disease progression before HCT. To summarize, CP X-351 is an effective and well-tolerated regimen for cytoreduction in pediatric sMDS/AML that warrants prospective studies.

Molecular Minimal Residual Disease Detection in Acute Myeloid Leukemia.

Simple SummaryAlthough the majority of patients with acute myeloid leukemia (AML) reach a morphologic complete remission after high-dose chemotherapy, the majority of them face a relapse within a few years. Detection of residual cells, persisting in a considerably small amount, has shown to be predictive of impending relapse in multiple studies. Whereas the gold standard in minimal residual disease (MRD) detection in AML is currently based on immunophenotypic approaches, the use of molecular MRD testing to predict AML relapse has been explored extensively in recent years. This review aims to provide an overview of the different studies that improve molecular MRD detection in AML, and to describe the limitations and challenges it faces.Initial induction chemotherapy to eradicate the bulk of acute myeloid leukemia (AML) cells results in complete remission (CR) in the majority of patients. However, leukemic cells persisting in the bone marrow below the morphologic threshold remain unaffected and have the potential to proliferate and re-emerge as AML relapse. Detection of minimal/measurable residual disease (MRD) is a promising prognostic marker for AML relapse as it can assess an individual patients’ risk profile and evaluate their response to treatment. With the emergence of molecular techniques, such as next generation sequencing (NGS), a more sensitive assessment of molecular MRD markers is available. In recent years, the detection of MRD by molecular assays and its association with AML relapse and survival has been explored and verified in multiple studies. Although most studies show that the presence of MRD leads to a worse clinical outcome, molecular-based methods face several challenges including limited sensitivity/specificity, and a difficult distinction between mutations that are representative of AML rather than clonal hematopoiesis. This review describes the studies that have been performed using molecular-based assays for MRD detection in the context of other MRD detection approaches in AML, and discusses limitations, challenges and opportunities.

Acute Promyelocytic Leukemia: Simplifying Treatment in a Resource Poor Setting

Introduction: Acute promyelocytic leukemia (APL) is a distinct leukemia which can be treated with differentiating agents alone.Treatment without chemotherapy decreases the cost of treatment and the need for supportive care. Here we present analysis of APL patients treated with arsenic trioxide (ATO)-all trans retinoic acid (ATRA) without chemotherapy in our hospital.Patients and Methods: Forty three patients with newly diagnosed APL were treated with arsenic trioxide(ATO ) and All trans retinoic acid (ATRA) during induction treatment. For consolidation ATRA 45 mg /m2 for two weeks every four weeks was administered for twenty eight weeks. ATO was administered for four cycles, with a cycle length of eight weeks. The drug was administered at 0.15 mg/kg/d for five days per week for four weeks during each cycle.Patients were followed up with once in three month hemogram and once in six month reverse-transcriptase polymerase chain reaction (RT-PCR) for two years and yearly thereafter. Results: The morphologic complete remission (CR) rate was 86.04%.The most common cause of remission failure was early death due to bleeding. None of the low risk patients died during induction therapy. The most important prognostic factor for early mortality was a high white blood cell (WBC) count at presentation. The median overall survival (OS) has not been reached.The two year OS was 83.4% and the three year OS was 74.8%.The estimated five year survival was 74.8%. At a median follow up of 42.6 months the estimated five year survival in the low-intermediate risk group was 93.3% and 59.1% in the high risk group Conclusion: ATO –ATRA can be considered as a treatment option for frontline treatment of all risk APL patients in resource poor settings.The results can be better with better supportive care to prevent early mortality and by salvaging patients who relapse.

Multivariate Analysis of Immune Reconstitution and Relapse Risk Scoring in Children Receiving Allogeneic Stem Cell Transplantation for Acute Leukemias.

Background.A timely and effective immune reconstitution after hematopoietic stem cell transplantation (HSCT) is of crucial importance to enhance graft-versus-leukemia reaction in hematological malignancies. Several factors can influence the yield of this process, and new mathematical models are needed to describe this complex phenomenon.Methods.We retrospectively analyzed immune reconstitution in the early post-HSCT period in a multicenter cohort of 206 pediatric patients affected by acute lymphoblastic leukemia, acute myeloblastic leukemia, and myelodysplastic syndrome who received their first allo-HSCT. All patients were in complete morphological remission at transplantation and were followed-up at least 26 mo post-HSCT. Blood samples for analysis of lymphocyte subset numbers were collected at day 100 (±20 d).Results.The 2-y cumulative incidence of relapse was 22.2% (95% confidence interval [CI], 17.3-27). Using principal component analysis, we identified based on 16 input variables a new multivariate model that enables patients’ description in a low-dimensional model, consisting of the first 2 principal components. We found that the numbers of CD3+/CD4+/CD8+ lymphocyte subsets at day 100 post-HSCT and acute graft-versus-host disease had the greatest impact in preventing relapse. We ultimately derived a risk score defining high- or medium-low–risk groups with 2-y cumulative incidence of relapse: 35.3% (95% CI, 25.6-45) and 15.6% (95% CI, 10.1-20.7), respectively (P = 0.001*).Conclusions.Our model describes immune reconstitution and its main influencing factors in the early posttransplantation period, presenting as a reliable model for relapse risk prediction. If validated, this model could definitely serve as a predictive tool and could be used for clinical trials or for individualized patient counseling.

ALL-318: Real-World Outcomes of Adults with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Who Did Not Receive Allogeneic Stem Cell Transplant at the University of Michigan

<h3>Context:</h3> The current standard of care for Ph+ ALL is concurrent chemotherapy or corticosteroids with a TKI, followed by an allogeneic transplant for those who are eligible and have attained complete morphologic remission. However, recent studies have suggested that transplant may not be necessary for all patients with Ph+ ALL, especially those who achieve CMR after induction. <h3>Objective:</h3> Our objective is to analyze the outcomes and characteristics of patients with Ph+ ALL treated within our institution who did not undergo allogeneic stem cell transplant. <h3>Design:</h3> We conducted a retrospective cohort study of patients with Ph+ ALL who did not undergo allogeneic stem cell transplant treated at the University of Michigan between 2007 and 2019. <h3>Main Outcome Measures:</h3> The primary outcome measurements of our study were overall survival (OS) and event-free survival (EFS). <h3>Results:</h3> 31 patients were identified in our database and met eligibility criteria. 30/31 patients received an upfront TKI (20 received dasatinib, 9 received imatinib, and 1 received ponatinib). 11 patients had molecular testing, and 4 had an IKZF1 mutation. The median OS was 388 days, with a median EFS of 247 days. 7 patients were deemed medically eligible for transplant but did not undergo transplant for reasons including patient preference and lack of an adequately matched donor. The median OS was 372 days for these 7 patients. 10/31 patients achieved CMR, with a median time to CMR of 148.5 days. The median OS in patients who achieved CMR was 551 days. The median OS for those who survived at least 50 days after diagnosis was 494 days. Cox regression analysis found an HR of.129 [0.020–0.841] for initial induction with hyperCVAD + TKI and an HR of 10.177 [1.209–85.677] with dexamethasone, vincristine, and TKI. No significant difference in OS was observed based on the choice of TKI. All patients who achieved CR experienced relapse or death during follow-up. <h3>Conclusions:</h3> Our results reveal poor outcomes in non-transplanted patients with Ph+ ALL and support the current standard of care utilizing concomitant chemotherapy and TKI with allogeneic transplant in those who are medically eligible.

Measurable Residual Disease in AML

Introduction Acute myeloid leukemia (AML) is a notoriously heterogeneous hematological malignancy with a relatively poor outcome depending on the risk classification, which is determined by white blood cell count (WBC), age, cytogenetics, and specific mutations.1 Although the majority of patients achieve a morphological complete remission (CR, defined as

Acute promyelocytic leukemia (APL) in very old patients: real-life behind protocols

Background Acute promyelocytic leukemia (APL) is uncommon among subjects aged ≥ 70 years and the better therapeutic strategy represents an unmet clinical need. Materials and methods This prompted us to explore our real-life data on a retrospective cohort of 45 older APL patients (≥ 70 years) consecutively diagnosed at eight different hematologic institutions in Latium, Italy, from July 1991 to May 2019. Results Two patients (4.4%) died from early hemorrhagic complications before treatment could begin. Twenty-two patients (51.1%) (Group A) were enrolled or treated according to standard clinical protocols, while 21 (48.8%) (Group B) received an ATRA-based personalized approach due to poor performance status. Morphologic complete remission (CR) after induction therapy was achieved in 33 patients (76.7%) with 100% of patients in Group A and 52.3% in Group B (p < 0.001). Molecular CR was documented in 30 patients (69.7%) [20/22 (90.9%) in Group A and 10/21 (47.6%) in Group B (p = 0.002)]. Ten patients (23.2%) died during induction therapy, all in Group B. Five-year overall survival (OS) of the entire cohort was 46.1% (95% CI 28.2–64.0), with 72.6% (95% CI 42.9–100) in Group A vs. 27.2% (95% CI 7.5–46.9) in the Group B (p = 0.001). Conclusions The present analysis highlights that almost half of the patients received sub-optimal induction treatments and registered dismal outcomes demonstrating the importance of adopting standard therapies instead of modified or reduced personalized approaches also in the setting of frail older patients.

MRD abnormal expression predict poor outcomes for refractory or relapsed acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation.

We retrospectively analyzed data from 197 patients with refractory or relapsed acute myeloid leukemia (r/rAML) who underwent allo‐HCT between January 2013 and February 2020 in our center (patients with promyelocytic leukemia were excluded). Of all patients, 86 achieved a complete morphological remission (CR) before transplant, while 111 failed to do so (NR). In the CR group, 32 patients displayed minimal residual disease (MRD‐positive). According to their immunophenotype pre‐HCT, we divided the MRD‐positive group and NR group into three subgroups: MRD 0+ group (without any antigen abnormal expression of CD7+, CD56+, CD38−, or HLA‐DR−) 28 patients, MRD 1+ group (with one abnormal antigen expression of CD7+, CD56+, CD38−, or HLA‐DR−) 63 patients, MRD 2+ group (with two or more abnormal antigens expression of CD7+, CD56+, CD38‐, or HLA‐DR‐) 52 patients. 3‐year estimates of disease‐free survival (DFS) for MRD 0+, MRD 1+ and MRD 2+ patients were 59.5 ± 9.5%, 29.9 ± 6.1%, and 9.4 ± 5.1%, and 3‐year estimates of overall survival (OS) were 59.5 ± 9.5%, 34.5 ± 6.3%, and 14.5 ± 10.8%, respectively. Multivariate analysis adjusted for genetic risk, blast cell level, secondary disease, age, sex, and donor relationship pre‐HCT, the hazard ratios of abnormal expression of CD7+, CD56+, HLA‐DR−, and CD38‐ were 6.69 (range 2.08–21.52; p = 0.001) for DFS, 2.24 (range 1.21–4.14; p = 0.010) for OS, and 7.18 (range 2.23–23.10; p = 0.001) for relapse compared with CD7−, CD56−, HLA‐DR+, and CD38+ patients. Our finding suggested that abnormal expression of CD7+, CD56+, HLA‐DR−, and CD38− is associated with poor outcomes, and the more number of abnormal antigens expression predict worse outcomes.

How to Improve Prognostication in Acute Myeloid Leukemia with CBFB-MYH11 Fusion Transcript: Focus on the Role of Molecular Measurable Residual Disease (MRD) Monitoring.

Acute myeloid leukemia (AML) carrying inv(16)/t(16;16), resulting in fusion transcript CBFB-MYH11, belongs to the favorable-risk category. However, even if most patients obtain morphological complete remission after induction, approximately 30% of cases eventually relapse. While well-established clinical features and concomitant cytogenetic/molecular lesions have been recognized to be relevant to predict prognosis at disease onset, the independent prognostic impact of measurable residual disease (MRD) monitoring by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), mainly in predicting relapse, actually supersedes other prognostic factors. Although the ELN Working Party recently indicated that patients affected with CBFB-MYH11 AML should have MRD assessment at informative clinical timepoints, at least after two cycles of intensive chemotherapy and after the end of treatment, several controversies could be raised, especially on the frequency of subsequent serial monitoring, the most significant MRD thresholds (most commonly 0.1%) and on the best source to be analyzed, namely, bone marrow or peripheral blood samples. Moreover, persisting low-level MRD positivity at the end of treatment is relatively common and not predictive of relapse, provided that transcript levels remain stably below specific thresholds. Rising MRD levels suggestive of molecular relapse/progression should thus be confirmed in subsequent samples. Further prospective studies would be required to optimize post-remission monitoring and to define effective MRD-based therapeutic strategies.

Prognostic value of lymphoid marker CD7 expression in acute myeloid leukemia patients undergoing allogeneic hematopoietic cell transplantation in first morphological complete remission.

Although defined as a lymphoid surface marker, CD7 is aberrantly expressed on a subtype of acute myeloid leukemia cells and appears to be associated with an inferior response to chemotherapy. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative modality but no data has been reported in CD7-positive AML patients. We performed a retrospective analysis involving 141 AML patients who underwent allo-HCT in first morphological complete remission (CR1). The results showed that CD7-positive AML patients had a poor 2-year overall survival (64.5% vs 82.0%, P = 0.040), relapse-free survival (RFS) (56.5% vs 79.4%, P = 0.005), and higher cumulative incidence of relapse (27.0% vs 9.7%, P = 0.003) post-HCT. In addition, expression of CD7 was related to RAS and RUNX1 mutation, and high residual disease level pre-HCT. Multivariate analyses showed CD7 expression at diagnosis was an independent risk factor for RFS (P = 0.016, HR = 0.418) and relapse (P = 0.014, HR = 0.307). We concluded that for AML patients in CR1, CD7 is a negative predictor for allo-transplant outcomes.

Clinical Characteristics and Treatment Outcome of Acute Myeloid Leukemia with APL-like Morphology and Uncommon RARA Fusion Variants

Background. Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) characterized by the translocation t(15;17) (q22;q21) generating the PML-RARA fusion gene. In rare cases of AML with APL like-morphology, RARA can be fused to an alternative partner other than PML (e.g. PLZF, NPM1 , NUMA1 , STAT5B, PRKAR1A and others) and this genetic heterogeneity accounts for the different sensitivity to targeted agents, such as all- trans retinoic acid (ATRA) and arsenic trioxide (ATO).Patients and methods. We collected data on 17 patients with AML characterized by variant RARA fusions, diagnosed between 2005-2017 from 13 institutions in US, Europe, Brazil, India and Australia. Of the 17 patients, 14 harboured PLZF-RARA, 1 PRKAR1A-RARA , 1 STAT5b-RARA rearrangements and 1 t(11;17)(q23;q21) with rearranged RARA.Results. Morphological data were compatible with classical M3 AML in all cases, and 38% presented with laboratory signs of coagulopathy. Flow cytometry was available in 12/17 cases and was compatible with classical APL, with 5/12 patients (42%) expressing CD56. Three cases were therapy-related AML due to previous exposure to radio-chemotherapy for solid tumors. Complete clinical-biological data are shown in Table 1. Most patients were adults (age range, 28-83 years), only two being younger than 18 years. Median WBC and platelet counts were 15.7 x 109/L (range, 2.18-248) and 69 x 109/L (range, 26-170), respectively, with 53% of patients presenting with WBC >10 x 109/L. Fourteen out of 17 patients received induction with ATRA + chemotherapy (CHT), either intensive or low-dose based on age and performance status. In addition, one patient received ATO combined with CHT and ATRA, 1 CHT alone and 1 ATRA alone. After induction, 11 patients achieved complete morphologic remission (CR) (of whom 2 after a second induction cycle); 2 are currently in partial remission (PR), 1 died early due to acute renal failure and 3 had resistant disease and received re-induction therapy that resulted in progressive disease in 2 and stable disease (SD) in one patient. Overall, the CR rate after induction therapy was 65%. Of the 13 patients who underwent consolidation therapy, 8 received ATRA+CHT, 2 CHT alone, 2 gemtuzumab ozogamicin (GO), and 1 azacytidine. Five of these patients underwent subsequent allogeneic hematopoietic stem cell transplant (HSCT) in first CR (3 from an HLA-matched sibling and 2 from matched unrelated donors). Four patients relapsed during follow-up (3 PLZF-RARA and 1 STAT5b-RARA ). Of these, 1 died of disease progression, 2 are alive in CR2 and CR4, respectively, and 1 is currently undergoing salvage therapy. With a median follow-up of 11 months (range: 1 - 86), 12/17 patients are alive (70.5%); of these, 9 are alive in CR, 2 are alive in PR and 1 alive with SD. Overall, five patients (29.5%) died, 3 from disease progression, 1 from transplant-related complications and 1 from acute renal failure during induction therapy.Conclusions. Despite the reported poor sensitivity of these RARA variants to standard APL therapy, this series suggests a relatively favorable outcome after treatment with ATRA combined with AML-like regimens including, in younger patients, allogeneic HSCT.The relative contribution of ATRA to achievement of CR and consolidation of remission remains to be further investigated.Table legend.*CR, complete remission; **mCR, molecular complete remission;+Res, resistant disease; °ED, early death;§PR, partial remissionATRA, All-trnas retinoic acid; IDA, idarubicin; DNR, daunorubicin; GO, gemtuzumab ozogamycin; ARA-C, cytaranine; L-DAC, low-dose cytarabine; HiDAC, high-dose cytarabine; MTZ, mitoxantrone; ETO, etoposide; ATO, arsenic trioxide;HSCT, hematopoietic stem cell transplantation;MUD, matched unrelated donor [Display omitted] DisclosuresCicconi:TEVA: Speakers Bureau. Montesinos:Celgene Corporation: Honoraria, Research Funding. Schwarer:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Specialised Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Lo Coco:TEVA: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Lundbeck: Honoraria, Speakers Bureau.

Longitudinal Detection of DNMT3AR882H Transcripts in Patients with Acute Myeloid Leukemia

Introduction The DNMT3A gene is recurrently mutated in normal karyotype acute myeloid leukemia (NK-AML) and the most common alteration (65% of cases) is located at residue R882 of methyltransferase domain. DNMT3A mutations often occur in association with other mutations such as FLT3 and NPM1 and while it is now generally accepted that AML patients with NPM1 or FLT3 -ITD mutations have favourable and poor outcome respectively, the impact of DNMT3A mutations on survival remains controversial. Recent studies reported that DNMT3A -mutated cells are detectable in patients with AML in long-lasting complete remission, questioning whether quantification of DNMT3A levels could be used to minimal residual disease (MRD). To address this issue, we carried out sequential monitoring studies of DNMT3AR882H levels in AML patients and compared our results with those obtained with multiparametric flow-cytometry (MPFC) and NPM1 molecular status and expression levels.Methods The mutational analysis of DNMT3AR882, NPM1 and FLT3 (ITD/TKD) was assessed at diagnosis in 556 patients with de novo AML (median age: 49 years, range 16-89 years) enrolled in clinical trials conducted by the Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA) during the period 2012-2015. DNMT3AR882H molecular status was also studied in 100 patients with chronic myeloid leukemia (CML) and in 56 elderly healthy individuals. The expression levels of DNMT3AR882H and NPM1 Type_A mutation (NPM1mutA) were longitudinally analysed by qRT-PCR in 21 AML patients. For patients achieving complete morphologic remission (CR), DNMT3AR882Hlevels were compared with those of NPM1mutA and with MRD assessed by multiparametric flow cytometry (MPFC). W e then compared the levels of DNMT3AR882H and of MPFC-MRD in follow-up BM-samples from AML patients in CR , classified as MRDneg or MRDpos, according to threshold established based on previous work from our group (Buccisano et. al. Blood 2010). Finally, we evaluated the kinetics of DNMT3AR882H, NPM1mutA and FLT3 -ITD in 9 FLT3 -ITD+ve patients, using a FLT3 -ITD patient-specific qRT-PCR, and in 6 FLT3 -wt patients.Results Expression levels of DNMT3AR882H was also studied in sorted cell subpopulations from AML and CML patients and in healthy individuals. Distinct from NPM1mutA, DNMT3AR882H expression levels did not correlate with leukemic blast proportion assessed by MPFC (Figure 1) and decreased in AML samples only after induction treatment (Figure 2), while it was constantly detectable during remission and at relapse (Figure 3). Within FLT3 -ITD+ve AML, the kinetics of DNMT3AR882H paralleled that of NPM1mutA in 3 of 9 patients only. DNMT3AR882H expression levels were constant, independent from NPM1mutA in all 6 FLT3 -wt patients. Figure 4 shows 4 exemplary cases, with stable DNMT3AR882H levels during disease course in three of them. In CML patients, the DNMT3AR882H transcript was found only during follow-up in 4/100 patients, while it was undetectable at the time of CML diagnosis. DNMT3AR882H transcript levels were constantly low in all available CML samples. As previously reported, clonal hematopoiesis of indetermined potential (CHIP) was identified in 3/56 elderly healthy individuals. Similarly low expression levels of DNMT3AR882H were detected in blast and T-lymphocyte samples obtained from AML cases at CR and relapse phases, in CML patients and healthy individuals (Figure 5 and 6). There were no differences in DNMT3AR882H expression between MRDpos and MRDneg follow-up samples. DNMT3AR882H transcripts levels in MRDpos follow-up samples were significantly lower than those of samples harvested at diagnosis (Figure 6). These data show that DNMT3AR882H mutations probably arise in very early hematopoietic precursors in the context of CHIP. Interestingly, as reported in figure 6, DNMT3AR882H expression levels were similar in samples from CML patients, healthy individuals and AML follow-up samples.Conclusions In summary, the results of our study indicate that DNMT3AR882H quantification is unreliable as a tool for AML monitoring. In fact, together with its detection in CML and healthy subjects, the presence of DNMT3AR882H at constant levels detected in AML during active disease or CR clearly point to a lack of specificity of this abnormality for the leukemic AML blast population. [Display omitted] DisclosuresCicconi:TEVA: Speakers Bureau. Lo Coco:Lundbeck: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; TEVA: Honoraria, Speakers Bureau.

Outcome of Children with Acute Leukemia Given Allogeneic HSCT Either from an Unrelated Donor or from an HLA-Partially Matched Relative after αβ-T Cell/B-Cell Depletion: A Multicenter, Retrospective, Comparative Analysis of the AIEOP Network

IntroductionFor patients in need of an allograft and lacking an HLA-identical sibling, hematopoietic stem cell transplantation (HSCT) from an unrelated donor (UD) is the standard of care. In the recent few years, αβ T-cell and B-cell depleted HLA-haploidentical HSCT (αβhaplo-HSCT) is becoming a widely employed alternative to UD-HSCT in patients with acute leukemia. We, thus, decided to conduct a retrospective analysis on the outcome of patients given either αβhaplo-HSCT or UD HSCT in the same time period, namely October 2010-December 2015, in one of the 13 centers affiliated with the Italian-HSCT pediatric network.Methods: Included in the study were 97 αβhaplo-HSCT recipients and 244 patients receiving UD-HSCT in the same period. Six centers performed both αβhaplo-HSCT and UD-HSCT, while only this latter procedure was performed in the remaining 7 centers. All children were transplanted in morphological complete remission (CR) after a fully myeloablative conditioning regimen. The UD was selected using high-resolution typing for the HLA-loci A, B, C, DRB1. The UD was 8/8 HLA-matched with the recipient in 52% of cases, while the remaining 48% of patients were transplanted from a donor with either 1 or 2 HLA-disparities. Details on patient characteristics of the 2 groups are shown in the Table; recipients of αβhaplo-HSCT were transplanted in more advanced phase and received more frequently a TBI-based regimen than UD-HSCT patients. Patients given αβhaplo-HSCT did not receive any post-transplantation pharmacological prophylaxis of graft-versus-host disease (GvHD), while the combination of anti-T lymphocyte globulin (ATLG), cyclosporine-A and short-term methotrexate was employed for preventing GvHD occurrence in all UD-HSCT recipients. ATLG was also infused before transplantation in all children treated with αβhaplo-HSCT to prevent both graft rejection and GvHD.Results: Two (2%) and 4 (2%) patients experienced graft failure in the αβhaplo-HSCT and UD-HSCT groups, respectively. Median time to neutrophil and platelet recovery was shorter in children given αβhaplo-HSCT (13 and 11 days vs. 19 and 23 days, respectively, P < 0.001 in both cases). The cumulative incidence (CI) of grade II-IV and grade III-IV acute GvHD in patients given αβhaplo-HSCT was 16% and 0%, as compared to 39% and 12% in UD-HSCT recipients (P < 0.001 and < 0.0005, respectively). Children treated with αβhaplo-HSCT benefited also from a lower incidence of both overall and extensive chronic GvHD (6% and 1%, respectively, vs 20% and 7% in UD-HSCT recipients, P < 0.01 and < 0.05, respectively), especially when compared with 7/8 and 6/8 UD-HSCT recipients. Forty-eight patients died for transplant-related complications: 9 (9%) and 40 (16%) in the αβhaplo-HSCT and UD-HSCT group, respectively, the CI of non-relapse- mortality (NRM) being 9% and 17% (P = N.S.). While the probability of NRM is superimposable in αβhaplo-HSCT and 8/8 UD-HSCT, 7/8 and 6/8 UD-HSCT had a higher risk of mortality (25% and 37%, respectively). Seventy-three children relapsed at a median time of 190 days (range 40-1603) after the allograft; no statistically significant difference for the CI of disease recurrence was observed between the 2 groups (25% vs 20%, respectively). With a median follow-up of 3.3 years (range 0.5-5 years for surviving patients) the 3-year probability of overall survival for patients given either αβhaplo-HSCT or UD-HSCT is 68% and 64%, respectively (P = N.S.), while that of event-free survival is 63% and 62%, respectively (P = N.S.). The 3-year chronic GvHD-free/relapse-free survival (GRFS) in the 2 groups is 59% and 48%, respectively (P = 0.03). GRFS of αβhaplo-HSCT or 8/8 UD-HSCT recipients was superimposable.Conclusions: Patients givenαβhaplo-HSCT had a faster ANC/PLT recovery and a lower probability of acute GvHD in comparison to children transplanted from an UD donor. Moreover, they also had a lower risk of NRM and better probability of GRFS in comparison to patients transplanted from an UD with 1 or 2 HLA-disparities. αβhaplo-HSCT is associated with a CI of disease recurrence comparable to that of children transplanted from an UD. Altogether, these data indicate that αβhaplo-HSCT is a competitive alternative to UD-HSCT, especially in the absence of a fully-matched donor. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Next-Generation Sequencing-Based Measurable Residual Disease (MRD) Monitoring Is Highly Predictive for Outcome after Allogeneic Stem Cell Transplantation

Background: Molecular predictors for relapse following allogeneic haematopoietic stem cell transplantation (alloHSCT) are urgently needed as 30-40% of AML patients experience recurrence of disease after HSCT. Measurable residual disease monitoring (MRD) for nucleophosmin 1 (NPM1 ) mutations has proven to be highly predictive for relapse in AML patients treated with or without alloHSCT. However, the majority of AML patients undergoing alloHSCT do not have the favorable NPM1 marker so that alternative markers and techniques are required. We studied a next-generation sequencing (NGS)-based error-corrected sequencing approach that is applicable to all mutations for its ability to prognosticate relapse and survival following alloHSCT.Aim: To evaluate the prognostic impact of MRD before alloHSCT in AML patients in morphologic complete remission (CR) using a novel approach of error-corrected sequencing applicable to the majority of AML patients.Patients and Methods: We studied 75 patients who underwent myeloablative (MA) (n=36) or reduced-intensity conditioned (RIC) (n=39) alloHSCT for AML in morphologic CR for the presence of MRD shortly before alloHSCT. All patients had at least one mutation in genes other than NPM1 or DNMT3A at the time of diagnosis that was identified by NGS with a myeloid panel on the Illumina platform. Amplicon-based error-corrected sequencing and bioinformatics was developed and applied to CR samples before alloHSCT analyzing 1-3 diagnostic mutations. Genomic DNA from peripheral blood (n=46) or bone marrow (n=29) was used for MRD assessment. Mutations in the following genes were used for MRD analysis in the indicated number of patients: IDH2 (n=12), FLT3 (n=10), RUNX1 (n=7), SF3B1 (n=6), NRAS (n=5), IDH1 and TP53 (n=4 each), KRAS and WT1 (n=3 each), CBL, ETV6, EZH2, STAG2 (n=2 each), BCOR, BCORL1, DDX41, PHF6, PTPN11, RAD21 , and SMC3 (n=1 each). 55 mutations were single nucleotide variants and 14 mutations were indels. The sensitivity of the assay was determined for each analysis and ranged from 10-4 to 10-5. Six patients (8%) had molecular persistence at high copy number in CR (variant allele frequency, VAF 31-51%) and were excluded from further analysis.Results: 31 of 69 patients (45%) were found MRD positive before alloHSCT with a median VAF of 0.19% (range 0.012% to 14.5%). Clinical and transplantation-associated characteristics were similarly distributed between MRD positive and negative patients. Cytogenetic risk according to MRC, ELN risk groups and molecular aberrations showed no significant differences between MRD positive and negative patients apart from more MRD positive patients being SF3B1 mutated. The median follow up was 6.1 years. 19 of 31 MRD positive patients (61%) and 7 of 38 MRD negative patients (18%) relapsed after alloHSCT. In MRD positive patients the MRD marker was also found in the majority of available relapse samples (9 of 11 patients, 82%). MRD negative patients who relapsed had lost the MRD marker in 4 of 5 available relapse samples (80%), suggesting high accuracy of our MRD assay. By competing risk analysis for cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) patients with positive MRD had a significantly higher CIR than MRD negative patients (P<.001; HR 4.85, 95% CI 1.95-12.1; 5 year CIR 67.7 vs 19%, Figure 1A), while NRM was not significantly different (P=.31; HR 0.44, 95% CI 0.09-2.14). Overall survival (OS) was significantly shorter in MRD positive compared to MRD negative patients (P=.029; HR 2.26, 95% CI 1.07-4.79; 5 year OS 38 vs 70%, Figure 1B). In multivariate analysis MRD status was an independent predictor of CIR (P<.001, HR 5.80, 95% CI 2.18-15.48) besides cytogenetic risk, and of OS (P=.013, HR 2.57, 95%CI 1.22-5.38) besides cytogenetic risk and WBC count.Conclusion: We provide evidence that NGS-based MRD monitoring can be applied to a large proportion of AML patients using almost any available molecular aberration. This approach requires morphologic confirmation of CR status in order to exclude patients with molecular persistence at high copy number, likely originating from preleukemic clones or germline mutations. NGS-based MRD is highly predictive of relapse and survival and may help refining transplant and posttransplant management in AML patients. [Display omitted] DisclosuresChaturvedi:Bayer Pharma AG, Berlin, Germany: Research Funding. Fiedler:Amgen, ARIAD/Incyte: Membership on an entity's Board of Directors or advisory committees; Amgen: Patents & Royalties; Amgen, Pfizer: Research Funding; Amgen, Gilead, GSO, Teva, Jazz Pharmaceuticals: Other: Support for meeting attendance.

Identification of Relapse Risk Using a Multiparameter Flow Cytometry-Based Detection of Minimal Residual Disease in Adult Patients with Acute Myeloid Leukemia at ELN Intermediate-Risk

Background: Minimal Residual Disease (MRD) measurement is a useful tool to refine prognosis in adult Acute Myeloid Leukemia (AML) patients in morphological complete remission (CR). Multiparametric flow cytometry (MFC) may provide independent prognostic information particularly in intermediate (Int)-I and Int-II ELN 2010 risk groups.Patients and methods: Analysis was performed on bone marrow (BM) aspirates of 120 ELN Int-I/II patients (pts) from 2 independent institutions, separately analyzed in two MFC labs. Treatment consisted of one-two idarubicin-based induction courses followed by High-dose-Ara-C consolidation and by allogeneic transplantation (NILG, n: 18/51; GIMEMA, n: 20/69). The median age was 49yr (18-73yr), F/M ratio was 49/71; de-novo and secondary AML cases were 94.2% and 5.8%, respectively. FLT3 gene was mutated in 41.7% of the patients (50/120), being wild type in 56.6% of the cases (68/120). FLT3-ITD was detected in 35.0% of the patients (42/120) and FLT3-D835 was detected in 7.5% of the patients (9/120). NPM1 gene was mutated in 31.6% of the patients (38/120) being wild type in 65.8% of the cases (79/120). ELN 2010 int risk groups were distributed as follows: 79.2% Int-I (n: 95) and 20.8% Int-II (n: 25). At diagnosis, a panel of 22 monoclonal antibodies, combined in four 8-color tubes, was employed to detect leukemia-associated immunophenotypes (LAIPs). MRD was measured after the first cycle (TP1) and after the second cycle (TP2). MRD was considered positive if residual leukemic cells were equal or higher than 0.1% and 0.035% at TP1, and than 0.035% at TP2, respectively. Relapse-free survival (RFS) and overall survival (OS) were analyzed using Kaplan-Meier curves and the log-rank test.Results: One-hundred-eighteen and 116 patients were tested at TP1 and TP2, respectively. At TP1, MRD-positivity was detected in 72.9% (86/118) at a threshold of 0.1% and 83.9% pts (99/118) at a threshold of 0.035%. Both thresholds were significant in predicting relapse (P=0.0002 and P=0.0158 for the 0.1% and the 0.035% threshold, respectively). We observed a shorter RFS in MRD-positive versus MRD-negative patients: median RFS was 10.8 months (0.1% threshold) and 11.3 months (0.035% threshold) in MRD-positive pts as compared to 28.5 months (0.1% threshold) and 19.5 months (0.035% threshold) in MRD-negative patients. Furthermore, MRD-positive pts presented with a significantly shorter OS as compared to MRD-negative patients (0.1% threshold, P=0.0185), with a median OS of 18.2 months as compared to 33.7 months for MRD-negative pts. When the 0.035% threshold was used, OS was not different between the two groups of pts. At TP2, MRD-positivity was detected in 75.8% of the pts (88/116) and significantly predicted relapse (P=0.0023, 0.035% threshold): the median RFS was 10.8 months in MRD-positive pts vs 26.3 months in MRD-negative. Moreover, we observed a significant improvement in terms of OS in MRD-negative vs MRD-positive pts (P=0.0411), the median OS being 37.0 and 18.2 months, respectively. Notably, the proportion of MRD-positive and MRD-negative patients did not differ in terms of age, sex, ELN risk classification, FLT3 mutational status, and number of allogeneic transplanted patients.Conclusions: Overall, our findings demonstrate a correlation between MRD levels by MFC and relapse risk in ELN-intermediate risk patients. The use of an allogeneic transplantation approach rather than other consolidation strategies in ELN-intermediate risk AML patients is often debated. MFC-based MRD potentially allows for a more appropriate and tailored post-remission therapeutic strategy in these AML patients. Furthermore, harmonization of MRD analysis between different labs and different protocols sharing a common technical approach seems to be feasible. Future prospective studies are warranted for prospective evaluation of MRD in ELN-intermediate AML patients. DisclosuresRossi:AbbVie: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees.

Final Analysis of the Phase I/II Study of CC-486 (Oral Azacitidine) Maintenance Therapy after Allogeneic Stem Cell Transplantation (Allo-SCT) in Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS)

Final Analysis of the Phase I/II Study of CC-486 (Oral Azacitidine) Maintenance Therapy after Allogeneic Stem Cell Transplantation (Allo-SCT) in Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS)