Hematopoietic Cell Transplantation In First Complete Remission Research Articles

Clinical features of immature leukemias in children.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), mixed phenotypic acute leukemia (MPAL), and acute myeloid leukemia with minimal differentiation (AML-M0) all originate from immature hematopoietic progenitor cells and have a poor prognosis. We investigated the clinical characteristics of these immature leukemias in 17 children (ETP-ALL: 8, MPAL: 5, AML-M0: 4) at seven institutions. Clinical and laboratory findings were comparable across disease types. Eleven and six patients received ALL- and AML-oriented induction chemotherapy, with six and four achieving complete remission (CR), respectively. Five additional patients achieved CR after salvage with the other type of chemotherapy. Eight patients received hematopoietic cell transplantation (HCT) in first CR, and six survived without relapse. However, six of seven patients who did not receive HCT during first CR relapsed; all underwent HCT later, and only three survived. The 5-year event-free survival (EFS) and overall survival (OS) rate were 37% and 69%, respectively. Patients who achieved CR after induction chemotherapy and received HCT in first CR had favorable EFS and OS. Notably, all patients who received HCT in first CR survived 5years after diagnosis. Appropriate induction chemotherapy and HCT in first CR could improve the outcome of immature leukemias.

A Multicenter Analysis of Allogeneic Transplant Outcomes in Patients with Philadelphia-like (Ph-like) Acute Lymphoblastic Leukemia (ALL)

Background: Ph-like ALL is a high-risk subset of B-lineage ALL that responds poorly to standard chemotherapy regimens. While allogeneic hematopoietic cell transplantation (HCT) is routinely recommended for patients with Ph-like ALL, large multicenter data addressing its role is limited. Here, we conducted a multicenter study to evaluate the role of HCT in adolescent and young adult (AYA) and adult patients (pts) with Ph-like ALL and compare their outcomes to pts with Ph-pos and Ph-neg (non-Ph-like) ALL. Methods: The study included pts (age ≥18) with B-lineage ALL who received HCT in first complete remission (CR1) at 3 academic centers (MD Anderson Cancer Center, City of Hope and Mayo Clinic) between 2006 and 2021. Pts were divided into 3 main subgroups: Ph-like, Ph-pos and Ph-neg ALL. Ph-like ALL cases were identified using cumulative data obtained by targeted RNA sequencing, conventional cytogenetics, FISH studies, whole genome chromosomal microarray and flow cytometry. Measurable residual disease (MRD) prior to HCT was measured using flow cytometry with a sensitivity of 0.01% for Ph-neg and Ph-like ALL, and with a PCR assay for BCR::ABL1 for Ph-pos ALL. MRD-negativity was defined as <0.01%. Predictors of relapse were evaluated in univariate and multivariate analysis using Fine-Gray sub-distribution hazard models considering non-relapse mortality (NRM) as a competing risk. Results: 673 patients were identified, 83 (12.3%) had Ph-like ALL, of which 73% had CRLF2-alterations. The remaining patients were classified either as Ph-pos (N=271, 40.3%) or Ph-neg ALL (N=319, 47.4%). Patients with Ph-like ALL were younger (median age 40 years vs 48 and 46 years for Ph-pos and Ph-neg ALL, respectively, p=0.01), more likely to be of Hispanic ethnicity (69% vs 32% and 48% for Ph-pos and Ph-neg ALL respectively, p<0.001). Patients with Ph-like ALL were also more likely to have induction failure (24% vs 2% and 11% for Ph-pos and Ph-neg ALL, respectively, p=0.001). A summary of pts characteristics for each subgroup can be found in Table 1. The median follow-up was 30, 52 and 48 months for patients with Ph-like, Ph-pos and Ph-neg ALL, respectively. In univariate analysis, 3-yr OS and PFS did not differ significantly (66% and 59% vs 59% and 54%, p=0.1) between patients with Ph-like and Ph-neg ALL, respectively. Similarly, the cumulative incidence of relapse was comparable between patients with Ph-like and Ph-neg ALL (22% vs 20%, respectively, p=0.7). In contrast, the 3-yr OS (75%, p<0.001) and PFS (70%, p=0.001) were significantly higher and relapse rate significantly lower (12%, p=0.003) in pts with Ph-pos ALL compared with Ph-like or Ph-neg ALL (Figure 1). The inferior survival in patients with Ph-like and Ph-neg ALL was likely attributable to higher relapse rates (22% and 20% vs 12%, respectively, p=0.003) compared to Ph-pos ALL. Finally, the 3-yr NRM rate in patients with Ph-like ALL was comparable (20% vs 18% and 23%, respectively, p>0.1) to Ph-pos and Ph-neg ALL. We confirmed that the relapse rate in patients with Ph-like ALL was comparable to the rate in pts with Ph-neg ALL (HR=1.02, 95% CI 0.6-1.8, p=0.9) on multivariate analysis (MVA). Ph-pos ALL was associated with a significantly lower relapse rate compared with Ph-neg ALL (HR=0.4, 95% CI 0.3-0.7, p<0.001). MRD positivity prior to allo-HCT was the only additional significant predictor for relapse on MVA (HR=2.9, 95% CI 1.8-4.7, p<0.001). Conclusions: HCT appears to overcome the poor prognosis of patients with Ph-like ALL. Despite higher induction failure rates, patients with Ph-like ALL undergoing HCT in CR1 had similar outcomes to other Ph-neg ALL subsets. The impact of effective salvage therapy leading to MRD-negativity in CR1 in this group is under investigation and will be reported. Further studies are needed to assess the impact of different Ph-like alterations on HCT outcomes. Outcomes for patients with Ph-pos ALL are significantly better than other groups, likely due to the use of TKIs pre- and post-HCT.

Molecular Relapse after First-Line Intensive Therapy in Patients with Core-Binding Factor and NPM1-Mutated Acute Myeloid Leukemia - a Filo Study

Background: Patients with Core-Binding Factor (CBF) and NPM1-mutated acute myeloid leukemia (AML) are considered as favorable or intermediate-risk according to the European LeukemiaNet (ELN) 2022 classification and allogeneic hematopoietic cell transplantation (HCT) is usually not considered in those achieving first complete remission (CR) with good molecular response. Close molecular monitoring by quantitative PCR has been widely implemented over time and approximately 30% of patients will experience molecular relapse. However, there is no recommendation on how to manage these patients due to the lack of data from large patient series or clinical trials. In this study, we retrospectively analyzed the outcome of CBF or NPM1-mutated AML patients who had MRD monitoring after having achieved first CR. Methods: All CBF and NPM1-mutated AML patients, aged 18-60 years, who had MRD molecular monitoring (RT-qPCR of RUNX1-RUNXT1 or CBFB-MYH1 transcripts or classical NPM1 mutations) after first-line therapy including induction therapy with daunorubicin/idarubicin and cytarabine followed by intermediate or high-dose cytarabine consolidation, without allogeneic HCT in first CR, were included. MRD measurements were generally performed every three months during follow-up for 24 months in either bone marrow (BM) or peripheral blood (PB). Molecular relapse was defined according to ELN recommendations (Heuser M, Blood 2021) as a conversion from MRD negativity to positivity or an increase in MRD copy numbers >1 log between two positive samples. Results: Between 2010 and 2019, 303 patients from 9 centers with newly diagnosed CBF or NPM1-mutated AML ( RUNX1-RUNX1T1, 19%; CBFB-MYH11, 27%; NPM1, 53%) and available MRD monitoring after first-line therapy were included. Among these patients, 153 (51%) never relapsed, 95 (31%) had molecular relapse, with a median of 326 days (interquartile range [IQR]: 276-438) from initial diagnosis, and 55 (18%) had upfront morphologic relapse (i.e., without prior molecular relapse detected), with a median of 388 days (IQR: 280-559). Patients with molecular and upfront morphologic relapse had higher white blood cell (WBC) count at diagnosis (12 vs. 22 vs. 30 G/l in those without relapse, molecular relapse, and morphological relapse, respectively, P=0.003) and were more likely to have a FLT3-ITD mutation (7% vs. 25% vs. 19%, respectively, P=0.001). In addition, patients with upfront morphologic relapse had a lower log-reduction of MRD during first-line treatment (4.90 vs. 4.93 vs. 3.77, respectively, P=0.009) and were more likely to have CR with positive MRD at the end of treatment in peripheral blood (2% vs. 16% vs. 32%, respectively, P<0.001). Overall survival (OS) was significantly different according to whether patients never relapsed, had molecular relapse, or had upfront morphological relapse (three-year OS of 100% vs. 75% vs. 60%, P<0.001; Figure A). Among the 95 patients with molecular relapse, 53 (56%) received preemptive therapy (median of 48 days [IQR:24-68] from molecular relapse to treatment initiation) and 42 (44%) progressed to morphologic relapse before treatment was initiated (median of 58 days [IQR:36-134] from molecular to morphologic relapse). Patients who received preemptive therapy had a better OS than those who received salvage therapy after having progressed from molecular to morphologic relapse, and those who had upfront morphologic relapse (78% vs. 51% vs. 51% at three years, respectively, P=0.01; Figure B). Preemptive therapy included upfront allogeneic HCT (n=19), intensive chemotherapy (n=21), and non-intensive therapy (n=13) with different OS rates that did not reach statistical significance (92% vs. 79% vs. 58% at three years for upfront allogeneic HCT, intensive chemotherapy, and less intensive therapy, respectively, P=0.09). Conclusion: Up to 30% of patients with CBF or NPM1-mutated AML experienced molecular relapse in our cohort and more than 50% of them received preemptive therapy. Patients treated preemptively at molecular relapse had a better OS than those treated with active disease. Although these results need to be confirmed in larger studies, it supports molecular monitoring during follow-up to start preemptive therapy before overt morphologic relapse. Other techniques for MRD monitoring are urgently needed for AML patients who cannot be monitored by qPCR.

Challenges of Maintenance Tyrosine Kinase Inhibitor Therapy after Allogeneic Hematopoietic Cell Transplantation in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

Background: Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) relapse after allogeneic hematopoietic cell transplantation (HCT) is difficult to manage. One strategy to prevent this is tyrosine kinase inhibitor (TKI) maintenance post-HCT, but the vast majority of data discusses the use of imatinib in this setting, with few reports on newer generation TKIs (NG-TKI). Here, we present our institutional experience with TKI maintenance post-HCT. Methods: Ph+ ALL patients who underwent HCT and received TKI maintenance anytime post-HCT from 2003-2019 were included through retrospective chart review. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS), and cumulative incidence of non-relapse mortality (NRM), cumulative incidence of relapse (CIR), and graft-vs-host disease (GVHD). OS and PFS were calculated via the Kaplan Meier method, NRM, CIR, and GVHD were calculated through a competing risk analysis, where CIR was used as a competing risk for NRM and GVHD, and NRM for CIR and GVHD. Results: 110 patients were included, and their baseline characteristics are described in Table 1. 45 (40.9%) patients received imatinib initially, and 65 (59.1%) received NG-TKI initially, of whom, 59 (90.8%) received dasatinib, 4 (6.2%) received nilotinib, and 2 (3.1%) received ponatinib. The median age (range) of the initial imatinib and NG-TKI groups were 42 years (19-64) and 47 (21-73), respectively. 25 (55.6%) vs 43 (66.2%) in the initial imatinib vs NG-TKI groups were >40 years, respectively. 18 (40.0%) vs 39 (60.0%) of the patients receiving initial imatinib vs NG-TKI were female (P=0.052). 20 (44.4%) vs 54 (83.1%) patients in the imatinib vs NG-TKI group underwent HCT ≥2010, respectively (P<0.001). 41 (91.1%) vs 57 (87.7%) in the imatinib vs NG-TKI groups underwent HCT in first complete remission (CR1) (P=0.76), and 21 (46.7%) vs 31 (47.7%) had no measurable residual disease (MRD) detected by PCR at the time of HCT, although 10 (22.2%) vs 10 (15.4%) did not have a PCR report at the time of HCT available (P=0.66). 42 patients (38.2%) required a dose reduction due to toxicity, and 67 patients (60.9%) experienced TKI interruption due to toxicity. Initial imatinib vs NG-TKI maintenance was discontinued in 20 (46.5%) vs 29 (44.6%) due to toxicity, respectively. The median cumulative initial TKI exposure in patients initially receiving imatinib and NG-TKI was 354 days (range, 6-4,473) and 301 days (range, 5-2,740), respectively. Reasons for TKI discontinuation are listed in Table 2. There was no difference in 5-year OS and PFS in patients receiving imatinib vs NG-TKI, 84.1% vs 69.8% (P=0.47) and 75.1% vs 62.5% (P=0.48), respectively. Likewise, 5-year NRM, 5-year relapse, and 4-year GVHD were similar between imatinib vs NG-TKI, 9.0% vs 18.3% (P=0.48), 15.9% vs 19.2% (P=0.92), and 40.7% vs 47.7% (P=0.47), respectively. Univariate analyses showed an improvement in OS and PFS in those who received ≥12 months of TKI maintenance vs those who received <12 months, hazard ratio (HR) 0.26 (95% confidence interval (CI), 0.12-0.55), P<0.001 and HR 0.33 (95% CI, 0.17-0.64), P<0.001. There was no difference in OS and PFS for those who completed ≥12 months of TKI maintenance based on initial TKI of choice, HR 0.85 (95% CI, 0.21-3.51), P=0.8 and HR 0.91 (95% CI, 0.28-2.94), P=0.9. Conclusions: Our findings demonstrate the challenges of delivering post-HCT TKI maintenance. Toxicity leading to TKI interruptions, discontinuation, and dose reduction was common. Post-transplant outcomes were comparable with imatinib and NG-TKI. Therefore, TKI selection for post-HCT maintenance should be based on patient tolerability to maximize TKI maintenance exposure. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Measurable residual disease (MRD) status before allogeneic hematopoietic cell transplantation impact on secondary acute myeloid leukemia outcome. A Study from the Acute Leukemia Working Party (ALWP) of the European society for Blood and Marrow Transplantation (EBMT).

Measurable residual disease (MRD) assessment before allogeneic hematopoietic cell transplantation (HCT) may help physicians to identify a subgroup of patients at high risk of relapse for de novo acute myeloid leukemia (AML) but its relevance among patients affected by secondary AML (sAML) is still unknown. We assessed the impact of MRD among 318 adult patients with sAML who received an allogeneic HCT in first complete remission. At the time of HCT, a total of 208 (65%) patients achieved MRD negativity, while 110 (35%) had positive MRD. 2-year overall survival (OS) was 58.8 % (95% CI 52.2-64.9) with leukemia-free survival (LFS) of 50.0 % (95% CI 43.7-56.1), relapse incidence of 34.2% (95% CI 28.4-40.1) and non-relapse mortality (NRM) of 23.3 % (95% CI 19-27.7) for the entire cohort. In multivariate analysis, HCT recipients with KPS ≥ 90 experienced less disease recurrence (HR 0.61, 95% CI 0.4-0.94) with better LFS (HR 0.63, 95% CI 0.44-0.89) and OS (HR 0.58, 95% CI 0.39-0.86). There were no differences in major clinical endpoints between patients with MRD-positive and MRD-negative status at the time of HCT. Pre-transplantation assessment of MRD was not informative on post-HCT outcomes in this retrospective registry-based analysis among patients affected by sAML.

Impact of diagnostic genetics on remission MRD and transplantation outcomes in older patients with AML

AbstractOlder patients with acute myeloid leukemia (AML) have high relapse risk and poor survival after allogeneic hematopoietic cell transplantation (HCT). Younger patients may receive myeloablative conditioning to mitigate relapse risk associated with high-risk genetics or measurable residual disease (MRD), but older adults typically receive reduced-intensity conditioning (RIC) to limit toxicity. To identify factors that drive HCT outcomes in older patients, we performed targeted mutational analysis (variant allele fraction ≥2%) on diagnostic samples from 295 patients with AML aged ≥60 years who underwent HCT in first complete remission, 91% of whom received RIC, and targeted duplex sequencing at remission in a subset comprising 192 patients. In a multivariable model for leukemia-free survival (LFS) including baseline genetic and clinical variables, we defined patients with low (3-year LFS, 85%), intermediate (55%), high (35%), and very high (7%) risk. Before HCT, 79.7% of patients had persistent baseline mutations, including 18.3% with only DNMT3A or TET2 (DT) mutations and 61.4% with other mutations (MRD positive). In univariable analysis, MRD positivity was associated with increased relapse and inferior LFS, compared with DT and MRD-negative mutations. However, in a multivariable model accounting for baseline risk, MRD positivity had no independent impact on LFS, most likely because of its significant association with diagnostic genetic characteristics, including MDS-associated gene mutations, TP53 mutations, and high-risk karyotype. In summary, molecular associations with MRD positivity and transplant outcomes in older patients with AML are driven primarily by baseline genetics, not by mutations present in remission. In this group of patients, where high-intensity conditioning carries substantial risk of toxicity, alternative approaches to mitigating MRD-associated relapse risk are needed.

Characteristics and outcome of patients with core-binding factor acute myeloid leukemia and FLT3-ITD: results from an international collaborative study.

The aim of this study was to evaluate the prognostic impact of FLT3-ITD in core-binding factor acute myeloid leukemia (CBFAML) in an international, multicenter survey of 97 patients of whom 52% had t(8;21)(q22;q22) and 48% had inv(16)(p13q22)/t(16;16)(p13;q22). The median age of the patients was 53 years (range, 19-81). Complete remission after anthracycline-based induction (n=86) and non-intensive therapy (n=11) was achieved in 97% and 36% of the patients, respectively. The median follow-up was 4.43 years (95% confidence interval [95% CI]: 3.35-7.39 years). The median survival after intensive and non-intensive treatment was not reached and 0.96 years, respectively. Among intensively treated patients, inv(16) with trisomy 22 (n=11) was associated with a favorable 4-year relapse-free survival rate of 80% (95% CI: 59-100%) as compared to 38% (95% CI: 27-54%; P=0.02) in all other patients with CBFAML/ FLT3-ITD (n=75). Overall, 24 patients underwent allogeneic hematopoietic cell transplantation (HCT), 12 in first complete remission and 12 after relapse. Allogeneic HCT in first complete remission was not beneficial (P=0.60); however, allogeneic HCT seemed to improve median survival in relapsed patients compared to that of patients treated with chemotherapy (not reached vs. 0.6 years, respectively; P=0.002). Excluding patients with inv(16) with trisomy 22, our data indicate that the outcome of CBF-AML patients with FLT3-ITD may be inferior to that of patients without FLT3-ITD (based on previously published data), suggesting that prognostically CBF-AML patients with FLT3-ITD should not be classified as favorable-risk. FLT3-inhibitors may improve the outcome of these patients.

Newly proposed threshold and validation of white blood cell count at diagnosis for Philadelphia chromosome-positive acute lymphoblastic leukemia: risk assessment of relapse in patients with negative minimal residual disease at transplantation-a report from the Adult Acute Lymphoblastic Leukemia Working Group of the JSTCT.

White blood cell count (WBC) at diagnosis is the conventional prognostic factor in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Nevertheless, little is known about the impact of WBC at diagnosis considering the minimal residual disease (MRD) status at allogeneic hematopoietic cell transplantation (HCT). We evaluated adult patients with Ph+ ALL who achieved negative-MRD and received HCT in first complete remission between 2006 and 2018. The entire cohort was temporally divided into derivation (n = 258) and validation cohorts (n = 366). Using a threshold of 15,000/μL, which was determined by a receiver operating characteristic curve analysis in the derivation cohort, high WBC was associated with an increased risk of hematological relapse in both the derivation cohort (25.3% vs. 11.6% at 7 years, P = 0.004) and the validation cohort (16.2% vs. 8.5% at 3 years, P = 0.025). In multivariate analyses, high WBC was a strong predictor of hematological relapse in the derivation cohort (HR, 2.52, 95%CI 1.32-4.80, P = 0.005) and in the validation cohort (HR, 2.32, 95%CI, 1.18-4.55; P = 0.015). In conclusion, WBC at diagnosis with a new threshold of 15,000/μL should contribute to better risk stratification in patients with negative-MRD at HCT.

Outcome of Acute Myeloid Leukemia Patients with Abnormal 12p after Allogeneic Hematopoietic Cell Transplantation at Fred Hutchinson Cancer Research Center

BackgroundClonal abnormalities of the short arm of chromosome 12 (Abn12p) are seen in 3~5% of patients with acute myeloid leukemia (AML). Anecdotal reports associate these aberrations with adverse disease prognosis; however, no large studies have been published to formally document its clinical impact on prognosis, especially in patients undergoing allogeneic hematopoietic cell transplantation (HCT). This study aimed to test the hypothesis that AML patients with Abn12p have an inferior survival outcome after HCT. Here we present data from 110 patients with Abn12p, to contrast with 442 comparable AML patients but without Abn12p, all who have received HCT at Fred Hutch.Patients and MethodsWe performed a retrospective comparative cohort analysis based on available data from the Gateway database at Fred Hutch. Inclusion criteria for the testing cohort was AML patients diagnosed according to the current WHO criteria with any chromosome 12p abnormality by karyotype analysis who underwent a HSCT at Fred Hutch. A comparison cohort of AML patients without 12p abnormality was identified based on the following matching criteria: patient age difference within 5 years, transplant time difference within 2 years, conditioning intensity, and donor type. Four matching patients were identified for each Abn12p patient. Overall survival (OS), cumulative incidence of relapse (CIR) and non-relapse-mortality (NRM) after HCT were analysed for the whole cohort and for patients receiving HCT in first complete remission (CR1).ResultsData from 552 patients with full karyotype information were analysed. The median age was 50 years with a range from 2 years to 80 years. Twenty-seven patients were younger than 18 years. Patients transplanted in CR1 accounted for 32% (=177/552), slightly lower among Abn12p patients than among the non-Abn12p patients (24% vs. 34%, P=0.045). 450 patients (82%) were treated with standard myeloablative conditioning (MAC) regimens while the remaining patients received reduced intensity conditioning (RIC). Donors were matched related in 38% (including 4% haploidentical), matched unrelated donors in 36%, and partially matched or mismatched unrelated donors in 14% of the patients. Thirty-nine patients received unrelated cord blood. With a median follow-up of 12 months (range from 0 to 370 months), the 5-year OS probabilities were 12% for the Abn12p patients and 41% for the non-Abn12p patients (Figure 1. Hazard ratio 2.33, P<0.0001, and 2.28 after adjustment for pre-transplant disease status). Patients transplanted in CR1 showed better outcome even among those with Abn12p. The 5-year survival probabilities were 25% for the Abn12p patients among those transplanted in CR1 and 6% for the other Abn12p patients (Figure 2, P=0.005). The primary cause of treatment failure was relapse. Cumulative incidence of relapse at three years was 29% and 56% for patients with and without Abn12p, respectively (P<0.0001). NRM was not significantly different between the two groups. Different types of 12p abnormalities - translocation, deletion, additional material of undefined origin, monosomy, and inversion - showed similar clinical associations with mortality and relapse. Co-variation analysis of cytogenetic abnormalities showed that complex and monosomal karyotypes were present in 82% and 60% of Abn12p patients, respectively, compared with 19% and 7% of non-Abn12p patients, respectively (both P-values < 0.0001). Abnormal chromosome 17p abnormalities were seen in 37% of Abn12p patients compared with 5% of non-Abn12p patients (P<0.0001). ELN classification of the Abn12p patients showed 85% unfavorable cytogenetics, 14% intermediate, and 2% favorable compared with 24%, 72%, and 4%, respectively, among non-Abn12p patients (P<0.0001).ConclusionIn conclusion, AML patients with Abn12p have a poor outcome after HCT. Abn12p tends to be present as part of a complex karyotype and hence considered unfavorable per ELN classification. Abn12p also overlaps with monosomal karyotype, but less so with 17p abnormalities. HCT in first complete remission still remains the treatment of choice for these patients. Clinical trial protocols should be considered for patients with Abn12p whenever possible. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Minimal residual disease (MRD) positivity at allogeneic hematopoietic cell transplantation, not the quantity of MRD, is a risk factor for relapse of Philadelphia chromosome-positive acute lymphoblastic leukemia

Minimal residual disease (MRD) monitoring by quantitative real-time reverse transcription PCR (qRT-PCR) is the standard of care in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). We evaluated the impact of MRD status at hematopoietic cell transplantation (HCT) on relapse, as measured by a unified protocol at a central laboratory. Only patients with Ph-positive ALL who had minor transcripts (e1a2) and who underwent allogeneic HCT in first complete remission between 2008 and 2017 were included. First, patients with negative-MRD (n = 196) and positive-MRD (n = 61) at HCT were analyzed. As expected, MRD positivity at HCT was significantly associated with an increased risk of hematological relapse (hazard ratio [HR], 2.91; 95% CI 1.67-5.08; P < 0.001) in the multivariate analysis. Next, patients with positive-MRD were divided into low-MRD (n = 39) and high-MRD (n = 22) groups. In the multivariate analysis, high-MRD at HCT was not significantly associated with an increased risk of hematological relapse compared to the low-MRD group (HR 1.10; 95% CI 0.54-2.83; P = 0.620). These results indicate that the therapeutic decisions should be made based on MRD positivity, rather than on the MRD level, at HCT.

Midostaurin in patients with acute myeloid leukemia and FLT3-TKD mutations: a subanalysis from the RATIFY trial

AbstractThe results from the RATIFY trial (ClinicalTrials.gov: NCT00651261; CALGB 10603) showed that midostaurin combined with standard chemotherapy significantly improved outcomes in patients with FMS-like tyrosine kinase 3 (FLT3)–mutated acute myeloid leukemia (AML), compared with placebo. In this post hoc subgroup analysis from the trial, we evaluated the impact of midostaurin in 163 patients with FLT3-tyrosine kinase domain (TKD) mutations. At a median follow-up of 60.7 months (95% CI, 55.0-70.8), the 5-year event-free survival (EFS) rate was significantly higher in patients treated with midostaurin than in those treated with placebo (45.2% vs 30.1%; P = .044). A trend toward improved disease-free survival was also observed with midostaurin (67.3% vs 53.4%; P = .089), whereas overall survival (OS) was similar in the 2 groups. Patients with AML and NPM1mut/FLT3-TKDmut or core binding factor (CBF)–rearranged/FLT3-TKDmut genotypes had significantly prolonged OS with or without censoring at hematopoietic cell transplantation (HCT), compared with NPM1WT/CBF-negative AMLs. The multivariable model for OS and EFS adjusted for allogeneic HCT in first complete remission as a time-dependent covariable, revealed NPM1 mutations and CBF rearrangements as significant favorable factors. These data show that NPM1 mutations or CBF rearrangements identify favorable prognostic groups in patients with FLT3-TKD AMLs, independent of other factors, also in the context of midostaurin treatment.

Redefining and measuring transplant conditioning intensity in current era: a study in acute myeloid leukemia patients.

To address limitations of the currently used reduced-intensity/myeloablative conditioning (RIC/MAC) classification scheme we aimed to develop a tool that can capture more standardized the conditioning intensity of allogeneic hematopoietic cell transplantation (HCT). We assigned intensity weight scores for frequently used conditioning regimen components and used their sum to generate the transplant conditioning intensity (TCI) score. We retrospectively tested the impact of TCI on 8255 adult (45-65 years) acute myeloid leukemia patients who underwent HCT in first complete remission. A Cox model for early nonrelapse mortality (NRM) yielded a 3-group TCI risk scheme (low, intermediate, high) with respective TCI scores of [1-2], [2.5-3.5] and [4-6]. On multivariate modeling, TCI grouping was highly and better predictive for early (day 100 and 180) NRM, 2-year NRM and relapse (REL) as compared with the RIC/MAC classification. Validation was done on 200 bootstrap samples. Moreover, TCI scoring enabled the identification of a distinct subgroup of RIC and MAC conditioning regimens with an intermediate TCI [2.5-3.5] score that had identical outcomes and which are frequently referred as "reduced toxicity conditioning". TCI scheme provides an improvement of the RIC/MAC classification. We propose TCI as a new tool to define and measure the conditioning regimen intensity.

Final Results of the AML12 Trial of the Spanish Cetlam Group in Adults with Acute Myeloid Leukemia (AML) up to the Age of 70 Years: Risk Adapted Post-Remission Allocation Based on Genetic Data and Minimal Residual Disease

BACKGROUND: AML risk classification is based on genetics (cytogenetics and molecular features) and more recently also on minimal residual disease (MRD) after chemotherapy. These two aspects allow predicting relapse and supporting or not the most anti-leukemia treatment that remains allogeneic hematopoietic cell transplantation (HCT). We prospectively investigated the combined use of the two predictive markers to allocate post-remission therapy with or without HCT. Objectives of the study were testing: a) if this approach was feasible in a multicenter setting; b) the proportion of patients who were allocated to an allogeneic HCT and finally received the procedure; c) the final distribution into the risk categories and their outcome; d) to analyze the outcome of patients with favorable or intermediate genetics moved to the high risk category because of positive MRD. METHODS: Adult patients with primary AML treated at 15 academic hospitals were included between February 2012 and December 2018. Induction chemotherapy consisted of idarubicin 12 mg/m2 days 1-2-3 and cytarabine 200 mg/m2 days 1 to 7. Consolidation courses were high-dose cytarabine (3 g/m2 or 1.5 g/m2 if ≥60 y/o). The number of consolidation courses was based on genetic risk: 3 in favorable genetics category (FGC) (CBF, NPM1mut/FLT3-ITDwild or ratio&amp;lt;0.5, and CEBPA biallelic mutation); and one in the intermediate genetics category (IGC), including intermediate cytogenetics without favorable or unfavorable (FLT3-ITD, MLL, EVI1) molecular features, as well as in adverse genetics category (AGC). Following, the mandatory option was allogeneic HCT in the AGC and in the other genetic categories when MRD was positive. In the IGC without MRD autologous or HLA preferentially matched allogeneic HCT was a center decision. MRD was assessed by flow (positive &amp;gt;0.1%) and/or quantitative PCR of the specific transcripts (RUNX1/RUNX1T1, CBFβ/MYH11 and NPM1). RESULTS: Seven hundred forty-five patients (median age: 55, range18-70 y/o, 51% male) were enrolled. Cytogenetics according the revised MRC classification in 707 informative cases was: CBF AML 12%, intermediate 65% (75% of them normal karyotype), and adverse 23%. FLT3-ITD was detected in 28% of patients with intermediate risk cytogenetics and NPM1 mutation in the same group was present in the 48%. Complete remission (CR) was achieved in 81% (n=603) of patients, 82% and 80% in patients up to and above 60 yrs, respectively. Induction death occurred in 9% of patients, 7% and 11% the two age groups, and 10% of patients had refractory leukemia; 542 (90%) of the 603 CR patients completed the consolidation phase and were risk allocated taking into account genetics and MRD. The remaining CR patients were not allocated because of early relapse (n=22), death in CR (n=5), severe toxicity (n=22) or others (n=12). After risk allocation, 208 (38%) patients were in the genetics-MRD combined favorable group (CFG), 103 (19%) in combined intermediate group (CIG) and 231 (43%) in the combined adverse group (CAG). In the latter, 185 (80%) of patients received an allogeneic HCT in first CR. Fifty-seven patients (11%) moved from the genetically FGC or IGC to the CAG because of high MRD at the end of consolidations. Median follow-up in survivors was 25 months. Overall 4-years survival (OS) of the whole series is 48±2%; event-free survival (EFS) is 77+3% in the CFG group, 45+6% in the CIG and 34+4% in the CAG (p&amp;lt;0.001) due to difference in the cumulative relapse incidence (19%, 38% and 45%, respectively, p&amp;lt;0.001 ). In the 57 patients who were MRD positive at the end of consolidation (FGC and IGC) had an OS of 53±8% and EFS of 45±7% at 4 years. CONCLUSION Risk adapted therapy for primary AML based on genetics and MRD is feasible in a cooperative group setting. The proportion of CR was high (&amp;gt;80%) even in patients older than 60 y/o. MRD assessment at the end of consolidation moved 57 patients with favorable or intermediate genetics to the CAG. Avoiding HCT in first CR in the FGC patients associated to EFS above 75% at 4 years. Allogeneic transplantation feasibility was 80% when this was the intended treatment because of adverse genetics and/or MRD positivity. Risk assessment based on genetics and MRD continues separating three groups of patients with different outcomes. Since relapses remain frequent when adverse AML features are present, further approaches after transplantation, such as targeted agents and immune therapies deserve investigation. Disclosures Sierra: Astellas: Honoraria; Pfizer: Honoraria; Daiichi-Sankyo: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Roche: Honoraria; Jazz Pharmaceuticals: Honoraria; Novartis: Honoraria, Research Funding, Speakers Bureau. Salamero:Daichii Sankyo: Honoraria; Pfizer: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Esteve:Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy; Daiichi Sankyo: Consultancy; Roche: Consultancy; Astellas: Consultancy, Speakers Bureau; Pfizer: Consultancy.

Hematopoietic Cell Transplantation in First Remission Amongst Adolescent and Young Adult Acute Lymphoblastic Leukemia: A Population-Level Analysis across the United States

Background:The optimal role of allogeneic hematopoietic cell transplantation (HCT) for adolescents and young adults (AYA) with acute lymphoblastic leukemia (ALL) is an area of clinical debate. In this population-based evaluation of AYA ALL patients across the United States (US), we sought to describe recent patterns of care and outcomes regarding HCT in first complete remission (CR1) amongst AYAs with ALL.Methods:Data were abstracted from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Patterns of Care (POC) study focused on AYA cancers. AYAs (15-39 years) with ALL newly diagnosed between January 1, 2012 through December 31, 2013 and registered in the SEER program were included. Allogeneic HCT in CR1 was defined as occurrence of HCT without relapse/progression prior to the HCT date; HCT was considered a time-dependent variable in survival models. Multivariable logistic regression was used to evaluate associations with HCT in CR1; cox proportional hazards regression was used to evaluate associations with survival.Results:Three-hundred and ninety-nine AYAs (15-39 years) with newly diagnosed ALL between 2012-2013 were included; median follow-up for survival was 19 months (range, 0-35 months). The median age was 24 years; 85% had B-cell ALL, 27% had high risk ALL cytogenetics. One-third of AYA ALL patients received care from pediatric oncologists while two-thirds were treated by adult hematologist/oncologists; a majority (86%) received care at a teaching hospital. Fifty-eight percent received an asparaginase-containing ALL front-line regimen, 32% received hyperCVAD; 5.9% and 4.5% received another/unknown regimens, respectively. One-hundred and two (29%) AYAs underwent allogeneic HCT in CR1. Excluding patients with relapse/progression or death within three months of diagnosis (n=32), older age, high-risk ALL cytogenetics, treatment by an adult hematologist/oncologist, and front-line therapy with hyperCVAD were variables significantly associated (all P< 0.05) with increased odds of HCT in CR1 in univariate analysis, while Hispanic ethnicity and public or no/other insurance were associated with significantly lower odds of HCT in CR1. In multivariate adjusted analysis, only high-risk cytogenetics (odds ratio (OR) 4.84, 95% confidence interval (CI) 2.99-7.83) and receipt of hyperCVAD (OR 1.84, 95% CI 1.07-3.16) retained significant associations with HCT in CR1. The two-year cumulative incidence of relapse, relapse-free survival (RFS), and overall survival (OS) of the entire cohort were 28.3% (95% CI 23.4%-33.4%), 69.3% (95% CI, 63.6%-74.3%), and 84.1% (95% CI 79.7%-87.5%), respectively. Two-year cumulative incidence of relapse was significantly lower in patients receiving HCT in CR1 as opposed to those not receiving HCT in CR1 (15.1%, 95% CI 8.1%-24.1% vs 32.8%, 95% CI 26.9%-38.9%). This translated into a significant improvement in 2-year RFS (83.6%, 95% CI 72.6%-90.5% vs 64.3%, 95% CI 57.5%-70.3%), but no statistically significant differences in 2-year OS (88.9%, 95% CI 80.8%-93.7% vs 82.5%, 95% CI 77.2%-86.7%). Among all patients, receipt of care at a non-teaching hospital (hazard ratio (HR) 2.14, 95% CI 1.22-3.75) and use of another/unknown regimen (HR 9.08, 95% CI, 4.83-17.06) were significantly associated with inferior OS.Conclusions:In the US, allogeneic HCT in CR1 is most commonly administered to AYA ALL with high risk cytogenetics and as consolidation therapy for those who receive front-line hyperCVAD, as opposed to asparaginase-containing ALL regimens. Consistent with prior studies, AYA ALL patients treated at non-teaching hospitals have inferior survival. Although the landscape of ALL therapy is changing, these data provide an important snapshot of the modern state of HCT in CR1 for AYA ALL. DisclosuresMuffly:Shire Pharmaceuticals: Research Funding; Adaptive Biotechnologies: Research Funding.

Autologous and Allogeneic Transplantation for Burkitt Lymphoma Outcomes and Changes in Utilization: A Report from the Center for International Blood and Marrow Transplant Research

Trends in utilization and outcomes after autologous or allogeneic hematopoietic cell transplantation (HCT) for Burkitt lymphoma were analyzed in 241 recipients reported to the Center for International Blood and Marrow Transplant Research between 1985 and 2007. The autologous HCT cohort had a higher proportion of chemotherapy-sensitive disease, peripheral blood grafts, and HCT in first complete remission (CR1). The use of autologous HCT has declined over time, with only 19% done after 2001. Overall survival at 5 years for the autologous cohort was 83% for those in CR1 and 31% for those not in CR1. Corresponding progression-free survival (PFS) was 78% and 27%, respectively. After allogeneic HCT, overall survival at 5 years was 53% and 20% for the CR1 and non-CR1 cohorts, whereas PFS was 50% and 19%, respectively. The most common cause of death was progressive lymphoma. Allogeneic HCT performed in a higher-risk subset (per National Comprehensive Cancer Network guidelines) resulted in a 5-year PFS of 27%. Autologous HCT resulted in a 5-year PFS of 44% in those undergoing transplantation in the second CR.

The Role of Hematopoietic Cell Transplantation (HCT) for Burkitt Lymphoma: a Report From the Center for International Blood and Marrow Transplant Research (CIBMTR)

AbstractAbstract 2390Burkitt lymphoma (BL) is an aggressive B cell lymphoma primarily affecting children and young adults and is characterized by the highest doubling time of any tumor. Cyclical intensive chemotherapy and rituximab confer high complete remission (CR) rates and 80% long term disease free survival in chemotherapy sensitive disease. The role of autologous (autoHCT) or allogeneic (alloHCT) transplant is not well described in BL. We report the outcomes of 241 recipients of HCT for BL between 1985 and 2007 reported to the CIBMTR. Five patients (pts) received syngeneic twin grafts in addition to autoHCT in 113 pts, HLA identical sibling alloHCT (SIB) in 80 pts and mismatched related or unrelated donor (UNR/MM) alloHCT in 48 pts. Baseline patient and disease related risk factors varied significantly between cohorts (table1). The autoHCT cohort had a higher proportion of pts with chemotherapy sensitive disease (86%), peripheral blood grafts (73%) and HCT in first CR (42%). In the UNR/MM cohort, 25% pts were chemotherapy resistant and only 6% were in CR1. The use of autoHCT has declined in recent years with the majority (81%) performed before 2001. Conditioning regimen for alloHCT was myeloablative in 88% (86% and 92% in SIB and UNR/MM respectively). Treatment related mortality (TRM) was higher in alloHCT recipients (table1). Cumulative incidence of relapse/progression at 5 yrs (95% CI) was 44 (35-53)% for autoHCT, 42(31-53)% for SIB and 48 (34-62)% for UNR/MM. For autoHCT, 5-yr progression free survival (PFS) was 48(39-58)%, 78% for those in first CR versus 27% for disease beyond CR1 (p<0.001). For alloHCT, 5-yr PFS was 50% for those in first CR versus 19% for disease beyond CR1 (p=0.001) (figure 1). 5-yr PFS was 30 (20-41)% for SIB and 22 (12-35)% for UNR/MM. Progressive BL was the commonest cause of death. Conclusion:While autoHCT and alloHCT are both feasible in patients with BL, the use of autoHCT appears to be declining in recent years concomitant with the advent of modern chemotherapy. AlloHCT was performed in those with considerably higher risk disease. Approximately one fifth of advanced BL pts receiving alloHCT beyond CR1 had long term disease free survival.VariableAUTOSIBUNR/MMN1138048Karnofsky score ≥9067%61%50%Median age31 (5–76)24 (3–55)22 (2–54)Median time diagnosis prior to HCT, mo7 (2–74)6 (1–29)9 (1–113)Bone marrow involvement @ diagnosis22%21%27%CR1 disease status prior to HCT42%34%6%Chemosensitive disease prior to HCT86%77%71%TRM @ 1 yr (95% CI)5 (2–10)26 (17–37)28 (16–41)PFS @ 5 yr (95% CI)48 (39–58)30 (20–41)22 (12–35)OS @ 5 yr (95%CI)54 (44–63)32 (22–43)23 (12–36) [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Myeloablative Hematopoietic Cell Transplantation for Acute Lymphoblastic Leukemia: Analysis of Graft Sources and Long-Term Outcome

Analysis of hematopoietic cell transplantation (HCT) for high-risk or recurrent acute lymphoblastic leukemia (ALL) using different donor sources is confounded by variable conditioning and supportive care. We studied 623 consecutive ALL myeloablative HCT (1980 to 2005). Donors were autologous (n = 209), related (RD; n = 245), unrelated (URD; n = 100), and umbilical cord blood (UCB; n = 69). After median of 8.3 years of follow-up, 5-year overall survival (OS), leukemia-free survival (LFS), and relapse were 29% (95% CI, 26% to 32%), 26% (95% CI, 23% to 29%), and 43% (95% CI, 39% to 47%), respectively. Treatment-related mortality (TRM) at 2 years was 28% (95% CI, 25% to 31%). Mismatched URD sources yielded higher TRM (relative risk [RR], 2.2; P < .01) and lower OS (RR, 1.5; P = .05) than RD or UCB HCT. Autografting yielded significantly more relapse (68%; 95% CI, 59% to 77%; P < .01) and poorer LFS (14%; 95% CI, 10% to 18%; P = .01). HCT in first complete remission (CR1) yielded significantly better outcomes than later HCT. In a 1990 to 2005 allogeneic CR1/second complete response cohort, 5-year OS, LFS, and relapse rates were 41% (95% CI, 35% to 47%), 38% (95% CI, 32% to 44%), and 25% (95% CI, 19% to 31%), respectively; 2-year TRM was 34% (95% CI, 28% to 40%). With RD, well-matched URD and UCB sources, 5-year LFS was 40% (95% CI, 31% to 49%), 42% (95% CI, 14% to 70%), and 49% (95% CI, 34% to 64%), respectively, while relapse was 31% (95% CI, 22% to 40%), 17% (95% CI, 0% to 37%), and 27% (95% CI, 13% to 41%). Acute graft-versus-host disease was associated with fewer relapses. Since 1995, we noted progressive improvements in OS, LFS, and TRM. Allogeneic, but not autologous, HCT for ALL results in durable LFS. Importantly, HCT using UCB led to similar outcomes as either RD or well-matched URD. HCT in early remission can best exploit the potent antileukemic efficacy of allografting from UCB, RD, or URD sources.

A retrospective comparison of autologous and unrelated donor hematopoietic cell transplantation in myelodysplastic syndrome and secondary acute myeloid leukemia: a report on behalf of the Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Hematopoietic cell transplantation (HCT) is an effective treatment for myelodysplasia (MDS) and secondary acute myeloid leukemia (sAML). In this study, outcome of 593 patients with MDS/sAML after autologous and allogeneic HCT from a matched unrelated donor (MUD) were compared. A total of 167 (28%) patients received HCT from MUD without prior chemotherapy (MUD-U). The rest received HCT in first complete remission (CR1) (Autologous (Auto-CR1), n=290 (49%), HCT from MUD (MUD-CR1), n=136 (23%)). Survival at 3 years was best in MUD-CR1 (50%) compared to Auto-CR1 (41%) and MUD-U (40%) (P=0.01). Similarly, disease-free survival was 44% for MUD-CR1 compared to Auto-CR1 (28%) and MUD-U (34%) (P=0.03). Treatment-related mortality was 17% in Auto-CR1 compared to MUD-CR1 (38%) and MUD-U (49%) (P<0.001). Relapse for Auto-CR1 was 62% compared to 24 and 30% for MUD-CR1 and MUD-U, respectively (P<0.001). Outcome was best for patients with low tumor burden transplanted 6-12 months after diagnosis. Factors influencing outcome at 3 years were mainly significant in the first 6 months. Only, relapse after autologous HCT remained constant over time. Outcomes after allogeneic HCT in patients of 20-40 and >40 years were similar. Autologous and Allogeneic HCT from MUD offer the possibility of long-term survival to patients with MDS/sAML.