alloHSCT In First Complete Remission Research Articles

Prognostic factors impacting post-transplant outcomes in adult T-cell acute lymphoblastic leukemia: a registry-based study by the EBMT acute leukemia working party.

T-cell acute lymphoblastic leukemia (T-ALL) predominantly affects individuals in late childhood and young adulthood. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative modality particularly in the setting of poor risk genetics and/or persistent minimal residual disease. Limited studies have directly explored the impact of patient- and transplant-related factors on post-transplant outcomes in T-ALL. Using a large dataset from the European Society for Blood and Marrow Transplantation registry, we identified 1907 adult T-ALL patients (70% male) who underwent their first allo-HSCT in first complete remission (CR1) from matched sibling donors (MSD; 45%), unrelated donors (UD; 43%) or haploidentical donors (12%) between 2010 and 2021. The median age at transplant was 33.4 years (18.1-75). The median follow up was 2.9 years. Most patients underwent total body irradiation (TBI)-based myeloablative conditioning (69%). The 2-year overall survival (OS) was 69.4%, and leukemia -free survival (LFS) was 62.1%. In multivariate analysis, advanced age at transplant negatively affected LFS (for each 10-year increment, HR = 1.11, p = 0.004), GVHD-free, relapse-free survival (GRFS) (HR = 1.06, p = 0.04), OS (HR = 1.12, p = 0.002), and non-relapse mortality (NRM) (HR = 1.23, p < 0.001). More recent years of allo-HSCT were associated with improved GFRS (For each 3-year increment, HR = 0.89, p < 0.001), OS (HR = 0.9, p = 0.02), and decreased NRM (HR = 0.82, p = 0.008). TBI improved LFS. (HR = 0.79, p = 0.02), GRFS (HR = 0.83, p = 0.04), and relapse incidence (RI) (HR = 0.65, p < 0.001). Female-to-male transplant negatively affected GRFS (HR = 1.21, p = 0.02) and OS (HR = 1.23, p = 0.048). In vivo T-cell depletion significantly improved GFRS (HR = 0.74, p < 0.001). This large study identified prognostic factors, such as age at transplant conditioning regimen, in influencing post-transplant in adult T-ALL patients undergoing allo-HSCT. Importantly, a significant improvement over time was noted. These findings hold great promise for new adapted treatment strategies and can serve as a benchmark for future studies in that setting.

Effect of sustained measurable residue disease negativity and post-remission treatment selection on the prognosis of acute lymphoblastic leukemia in adults.

To explore the effects of monitoring measurable residual disease and post-remission treatment selection on the clinical outcomes of B-cell acute lymphoblastic leukemia (B-ALL) in adults. Between September 2010 and January 2022, adult patients with B-ALL who received combination chemotherapy, with or without allogeneic hematopoietic stem cell transplantation (allo-HSCT), were included in the retrospective study, which was approved by the Ethics Committee and the observation of Declaration of Helsinki conditions. One hundred and forty-three B-ALL patients achieved complete remission (CR) were included in the study, of whom 94 patients (65.7%) received allo-HSCT in first complete remission (CR1). Multivariate analysis showed that the most powerful factors affecting OS were transplantation (hazard ratio [HR] = 0.540, p = 0.037) and sustained measurable residue disease (MRD) negativity (HR = 0.508, p = 0.037). The subgroup analysis showed that the prognosis of the allo-HSCT group was better than that of the chemotherapy group, regardless of whether MRD was negative or positive after two courses of consolidation therapy. After consolidation therapy, the prognosis of patients with positive MRD remained significantly better in the allo-HSCT group than in the chemotherapy group. However, no significant difference was observed in the prognosis between the allo-HSCT and chemotherapy groups with negative MRD after consolidation therapy. B-ALL patients who achieve sustained MRD negativity during consolidation therapy have excellent long-term outcomes even without allo-HSCT. Allo-HSCT is associated with a significant benefit in terms of OS and DFS for patients who were with positive MRD during consolidation therapy.

Mixed Phenotypic Acute Leukemia -Clinical Presentation, Prognosis and Outcomes of Patients Treated with Acute Lymphoblastic Leukemia like Protocols a Multi-Institutional Study from India

Mixed phenotypic acute leukemia (MPAL) is a rare and difficult to treat type of acute leukemia. Broad consensus favour use of acute lymphoblastic leukemia (ALL) like treatment protocols in the management of MPAL. Data regarding this rare diagnosis is limited mainly to retrospective studies and limited data available from low middle income countries (LMIC). We report epidemiology and real-world outcome data of MPAL patients treated with ALL like protocols among the multi-institutional data base set up by hematology cancer consortium (HCC) in India. In this retrospective multicentric study of a prospectively maintained data set, we collected data from eleven member centers of HCC using an electronic database. Patients who fulfilled the WHO 2016 classification criteria for MPAL were included. Patients diagnosed between January 2018 and March 2022 were included in the study. The data included demographic details, performance status (ECOG), comorbidities, CNS involvement, testicular involvement, presence of mediastinal mass, phenotype of MPAL (B+M, T+M, T+B), karyotype, FISH, PCR and NGS abnormalities. If treatment was not received by patients the reasons were also captured. We also evaluated the treatment protocol used and use of tyrosine kinase inhibitors. The primary objective was to evaluate event-free survival (EFS) and overall survival (OS) at 1year. The impact of the treatment protocol used, age, baseline WBC count, LDH, performance status, CNS involvement on EFS and OS were studied. A total of 114 patients were diagnosed to have MPAL during the study period. The baseline epidemiological features are tabulated in table-1. Sixty-six (58%) patients were treated with ALL like treatment protocols and 48(42%) patients did not receive any treatment due to various reasons at HCC centers. 49(74%) patients received paediatric inspired protocols and 17(26%) patients received adult-type of protocols. Forty three (65%) patients achieved a complete remission after induction. Ten(15%) patients died during induction. Six(9%) patients died after achieving CR of which 3 died due to infection,3 died due to progressive disease and rest were lost to follow up. Minimal residual disease (MRD) done using either flowcytometry or PCR was available in 37 patients. MRD negative status was achieved in 17(46%) patients post phase II of induction. After a median follow up of 12 months, EFS was 61% and OS was 67%(figure1). Estimated EFS and OS at 24 months were 42% and 55% respectively. There were no significant differences in EFS and OS between different MPAL phenotypes. Allogeneic stem cell transplant (ASCT) was performed only in 3 patients. Negative MRD status at the end of second phase of induction was significantly associated with improved EFS with a Hazard ratio of 0.349(CI-0.117-1.036). Age, cytogenetic profile, LDH, baseline WBC count and CNS involvement were analyzed by univariate analysis for effect on treatment outcomes. There was no significant effect of these variables on both EFS and OS. Our study is one of the largest studies conducted on MPAL patients in a resource limited setting. If patients received treatment, the outcomes were encouraging despite poor access to allogeneic stem cell transplant in first complete remission, when compared with similar real world multi-institutional analysis. Induction mortality of 10% was comparable to other similar studies. However, the worse 2-year EFS and OS may be explained by poor rates of allogeneic stem cell transplant (Allo-HSCT). The abandonment of treatment and limited use of Allo-HSCT in first complete remission were major limitations in improving overall outcomes in our patients.

Prognostic Factors Impacting Post-Transplant Outcomes in Adult T-Cell Acute Lymphoblastic Leukemia: A Registry-Based Study By the EBMT Acute Leukemia Working Party

Background: T-cell acute lymphoblastic leukemia (T-ALL) predominantly affects individuals in late childhood and young adulthood and historically had high mortality rates. The outcome of Pediatric inspired chemo protocols in the T-ALL have improved in the past years due to the advancement in treatment and supportive care but the data is less mature, although adult patients still face challenges. Limited studies have directly explored the impact of patient- and transplant-related factors on post-transplant outcomes in adult T-ALL patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: A retrospective registry-based analysis was conducted across multiple centers using data from the European Society for Blood and Marrow Transplantation (EBMT) registry. Inclusion criteria were adult T-ALL patients (&amp;gt;18 years old) who underwent their first allo-HSCT in first complete remission from matched sibling donors (MSD), unrelated donors (UD) (10/10 or 9/10) or haploidentical donors between 2010 and 2021. Cord bloods were excluded. Multivariable Cox regression analysis was performed to examine the associations between patient/transplant characteristics and outcomes. Results: A total of 1907 patients were included in the study. The median age at transplant was 33.4 years (18.1-75). The median follow up was 2.9 years (2.6-3.1), and the median year of HSCT was 2016 (2010-2021). Patients were 70 % male with 67% being CMV-positive, at the time of transplant. Donors were predominantly male (64%), and (23%) of transplants involved female donors to male patients. The median period between diagnosis and HSCT was 5.9 months (0 -23.8). Most transplants were from matched sibling donors (MSD) (45%) followed by UD (43%) and 12% were from Haploidentical transplants. Most patients underwent myeloablative conditioning with total body irradiation (TBI)-based regimens (69%) and most patients received peripheral blood stem cells (84%). Cyclosporine with methotrexate was the most common graft-versus-host-disease (GVHD) prophylaxis (54 %). In vivo T cell depletion was used in 44%. The 2-year overall survival (OS) was 69.4%, and leukemia -free survival (LFS) was 62.1%. The cumulative incidence of acute GVHD (aGVHD) grades II-IV at 100 days was 32.6%, and grades III-IV was 10%. The cumulative incidence of chronic GVHD (cGVHD) at 2 years was 37.3%, and extensive cGVHD was 16.8%. Multivariate analysis yielded significant associations between patient/transplant characteristics and outcomes. Advanced age at transplant was associated with poorer outcomes, including LFS (HR=1.11, p=0.004), GVHD-free, relapse-free survival (GRFS) (HR=1.06, p=0.04), OS (HR=1.12, p=0.002), and higher non-relapse mortality (NRM) (HR=1.23, p=0.001); HR for 10y increment. A later year of HSCT was associated with improved GFRS (HR=0.89, p=0.001), OS (HR=0.9, p=0.02), and decreased NRM (HR=0.82, p=0.008), aGVHD II-IV (HR=0.83, p=0.001), and cGVHD (HR=0.8, p=0.001); HR for 3y increment. TBI was specifically superior with improved LFS (HR=0.79, p=0.02), GRFS (HR=0.83, p=0.04), and lower relapse incidence (RI) (HR=0.65, p=0.001). Female-to-male transplant combination had a negative impact on GFRS (HR=1.21, p=0.02), OS (HR=1.23, p=0.048), and on the risk of cGVHD in general (HR=1.39, p=0.002) and specifically extensive cGVHD (HR=1.47, p=0.01). The use of in vivo T-cell depletion had significant benefits in terms of GFRS, aGVHD grade III-IV, cGVHD, and extensive cGVHD. Conclusion: This large study identified prognostic factors, such as age at transplant, donor type, and conditioning regimen, in influencing key outcomes including OS, LFS, GVHD incidence, and NRM in adult T-ALL patients undergoing allo-HSCT. Importantly, a significant improvement over time in post-transplant outcomes was noted. These findings hold great promise for new adapted treatment strategies and can serve as a benchmark for future studies in that setting.

Chemotherapy with the use of next-generation TKIs based on MRD has the potential to avoid hematopoietic stem cell transplantation in treatment for adults with Philadelphia chromosome-positive acute lymphoblastic leukemia.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) as postremission treatment is recommended for Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL) in current guidelines. However, comparisons of later generation tyrosine kinase inhibitors (TKIs) plus chemotherapy with allo-HSCT have yielded similar outcomes. This meta-analysis was performed to evaluate allo-HSCT in first complete remission (CR1) versus chemotherapy for adult Ph+ALL in the TKI era. Pooled assessment of the hematologic and molecular complete response rates was performed after 3-month TKI treatment. Hazard ratios (HRs) were determined for disease-free survival (DFS) and overall survival (OS) benefit with allo-HSCT. The effect of measurable residual disease status on survival benefit was also analyzed. Thirty-nine retrospective and prospective single-arm cohort studies involving 5054 patients were included. Combined HRs indicated that in the general population, allo-HSCT favorably influenced DFS and OS. Achieving complete molecular remission (CMR) within 3months after starting induction was a favorable survival prognostic factor regardless of whether the patient had undergone allo-HSCT. Among the patients with CMR, survival rates in the nontransplant subgroup were comparable with those in the transplant subgroup, with the estimated 5-year OS of 64% versus 58% and 5-year DFS of 58% versus 51%, respectively. The use of next-generation TKIs results in a higher proportion of patients achieving CMR (ponatinib 82% vs. imatinib 53%), while improving survival in nontransplant patients. Our novel findings suggest that combination chemotherapy plus TKIs leads to a comparable survival benefit as with allo-HSCT for MRD-negative (CMR) patients. This study provides novel evidence for allo-HSCT indications for Ph+ALL in CR1 in the TKI era.

AML-396 Venetoclax-Containing Regimens Improve Outcomes of Intensive Treatment and Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Extramedullary Acute Myeloid Leukemia

The optimal treatment strategy for patients with extramedullary acute myeloid leukemia (eAML) is questionable, especially as applied to extramedullary tumor persistence while bone marrow response is achieved. To determine whether venetoclax-containing regimens, intensive treatment, and allogeneic hematopoietic stem cell transplantation (alloHSCT) can improve outcomes in patients with eAML. Overall, 27 patients with verified eAML were included: 14 were male and 13 were female with a median age of 40 years (13-84). Standard ("7+3"), high-intensity ("HiDAC", "FLAG±Ida"), and low-intensity chemotherapy regimens were administered to all patients. Ten patients (37%) received venetoclax with 5-azacytidine (VEN-AZA) because of comorbidities or refractory disease. AlloHSCT was performed in 17 patients (63%). According to the 2017 ELN risk stratification system, 18.5% (5/27) were favorable risk, 25.9% (7/27) were intermediate risk, and 55.6% (15/27) were adverse risk. Patients with favorable genetic alterations achieved bone marrow remission more frequently (100% vs. 44%, P=0.044) but did not have advantages in the rate of complete extramedullary response (75% vs. 68%, P>0.05). Using HiDAC enabled eradication of extramedullary lesions in case of failure of standard and low-intensity regimens (85% vs. 0%, P=0.044) and decreased the rate of early (during the first 12 months) relapse (38% vs. 100%, P=0.019). The overall response rate to VEN-AZA was 70% (7/10). Five patients (50%) achieved complete eradication of extramedullary tumor after venetoclax; among them, 3 still had persistent extramedullary disease after HiDAC. Performing alloHSCT in first complete remission decreased the risk of early relapse (12% vs. 80%, P=0.015) and demonstrated better median overall survival (38.85 vs. 7.57 months, P=0.013) and relapse-free survival (38.85 vs. 3.78 months, P=0.0021) compared to alloHSCT performed in second and subsequent complete remissions. Favorable genetic aberrations do not increase the frequency of extramedullary response. Intensive treatment helps to achieve complete eradication of extramedullary tumor and reduces early relapse rate. Using VEN-AZA is effective among patients with eAML, including patients who were refractory to intensive treatment, and allows complete response achievement before alloHSCT. The best time to perform the alloHSCT among patients with eAML is the first complete remission.

Characteristics and Outcome of Patients with Acute Myeloid Leukemia and t(6;9)(p22;q34)

Background: Acute myeloid leukemia (AML) with t(6;9)(p22;q34) is a distinct entity in the 2016 World Health Organization classification of myeloid neoplasms and accounts for a small subgroup (1-2%) of AML patients. A substantial proportion of AML patients with t(6;9) have a concomitant FLT3 -ITD. While outcomes are dismal with intensive chemotherapy, limited evidence suggests allogeneic hematopoietic stem cell transplantation (allo-HSCT) may improve survival if applied early during first complete remission (CR). However, neither prospective nor larger retrospective cohort studies are available to support these results which are derived from small series.Aims: To characterize AML patients with t(6;9)(p22;q34) and compare outcomes with different treatment strategies.Methods: We retrospectively studied 123 AML patients with t(6;9)(p22;q34) (median age at diagnosis, 46 years; range, 16-76 years) treated between 1989 and 2016 within fourteen study groups/institutions of the US and Europe. Standard statistical methods were applied.Results: Median white blood cell count at diagnosis was 20/nl (range, 0.5-274/nl) and platelets 52.5/nl (range, 9-332/nl). The type of AML was de novo in 111 (90%), secondary after myelodysplastic syndrome/myeloproliferative neoplasm in 9 (8%), and therapy-related in 3 (2%) of the patients.Fifty-four patients (44%) were female. Cytogenetic analysis revealed additional abnormalities in 25 (20%) patients, most frequently ≥3 (n=15) abnormalities including +8 (n=2), +13 (n=1) or combined +8/+13 (n=4). A total of 76 patients (62%) had FLT3 -ITD mutation testing, and 48 (63%) of those patients harbored FLT3 -ITD mutations.Data on response to intensive anthracycline-based induction therapy were available in 121 patients. CR was achieved in 79% (n=95) with 16/95 (17%) requiring an intensive salvage treatment cycle with HiDAC. The CR rate in FLT3 -ITD positive patients was 88% (n=42/48) as compared to 68% (n=19/28) in FLT3 -ITD negative patients (p=0.07). An allo-HSCT was performed in 75 (61%) patients, of whom 51 patients were transplanted in first CR after induction therapy. Additionally 6 patients achieved first CR after salvage chemotherapy and went on to allo-HSCT. Overall, the majority of patients underwent allo-HSCT in first (n=57) or second (n=9) CR; another 9 patients received allo-HSCT with active disease. Type of donor was matched-related in 31, matched-unrelated in 31, haplo-identical in 8, cord blood in 4, and unknown in 1 of the 75 patients, respectively. The majority of patients (72%) received myeloablative conditioning, including TBI in half of them. The proportion of patients receiving an allo-HSCT increased over the time.Median follow-up for the entire cohort was 61 months (95%-CI, 47-83%). Five-year overall survival (OS) was 36% (95%-CI, 28-47%). Five-year relapse-free survival (RFS) and OS were 50% (95%-CI, 36-68%) and 55% (95%-CI, 41-74%) in patients proceeding to allo-HSCT in first CR after induction therapy (n=51), as compared to 8% (95%-CI, 3-24%; p<0.001) and 18% (95-CI, 9-36%; p<0.001), respectively, in those who received consolidation chemotherapy (n=44). Of note, OS rates after allo-HSCT were comparable if performed in CR1 (56%; 95%-CI, 43-73%; n=57), CR2 (58%; 95%-CI, 30-100%; n=9) or active disease (53%; 95%-CI, 28-100%; n=9; p=0.91). In subgroup analysis FLT3 -ITD positivity had no prognostic impact on OS, either in the total analyzed cohort (p=0.11), or in those patients proceeding to allo-HSCT (p=0.37). Similarly, additional chromosomal abnormalities had no prognostic impact on OS in the afore mentioned cohorts (p=0.92; p=0.83; respectively).Conclusions: Our cohort of AML patients with t(6;9)(p22;q34) showed a high CR rate after intensive induction therapy; however, treatment with chemotherapy alone resulted in dismal survival outcomes. Those patients who proceeded to allo-HSCT achieved very encouraging OS rates, regardless of FLT3- ITD status, additional cytogenetic abnormalities or timing of transplant, suggesting that transplant should be standard of care when possible for these patients. DisclosuresKayser:Novartis: Honoraria, Speakers Bureau; TEVA: Honoraria. Perl:Pfizer: Other: Advisory Board; Novartis: Other: Advisory Board; Actinium Pharmaceuticals: Other: Scientific Advisory Board; Arog Pharmaceuticals: Consultancy; Seattle Genetics: Other: Advisory board; Daiichi Sankyo: Consultancy; Asana Biosciences: Other: Scientific advisory board; Astellas: Consultancy. Mayer:Eisai: Research Funding; Novartis: Research Funding. Walter:ADC Therapeutics: Research Funding; Aptevo Therapeutics: Research Funding. Stone:Ono: Consultancy; Celgene: Consultancy; Fuji Film: Consultancy; Arog: Consultancy; Pfizer: Consultancy; Novartis: Consultancy; Abbvie: Consultancy; Amgen: Consultancy; Agios: Consultancy; Astellas: Consultancy; Jazz: Consultancy; Sumitomo: Consultancy. Levis:Daiichi Sankyo, Inc.: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Research Funding; FujiFilm: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Astellas Pharma Us: Consultancy, Research Funding.

Midostaurin after allogeneic stem cell transplant in patients with FLT3-internal tandem duplication-positive acute myeloid leukemia

We evaluated standard-of-care (SOC) treatment with or without midostaurin to prevent relapse following allogeneic hematopoietic stem cell transplant (alloHSCT) in patients with acute myeloid leukemia (AML) harboring internal tandem duplication (ITD) in FLT3. Adults (aged 18–70 years) who received alloHSCT in first complete remission, had achieved hematologic recovery, and were transfusion independent were randomized to receive SOC with or without midostaurin (50 mg twice daily) continuously in twelve 4-week cycles. The primary endpoint was relapse-free survival (RFS) 18 months post-alloHSCT. Sixty patients were randomized (30/arm); 30 completed all 12 cycles (midostaurin + SOC, n = 16; SOC, n = 14). The estimated 18-month RFS (95% CI) was 89% (69–96%) in the midostaurin arm and 76% (54–88%) in the SOC arm (hazard ratio, 0.46 [95% CI, 0.12–1.86]; P = 0.27); estimated relapse rates were 11% and 24%, respectively. Inhibition of FLT3 phosphorylation to <70% of baseline (achieved by 50% of midostaurin-treated patients) was associated with improved RFS. The most common serious adverse events were diarrhea, nausea, and vomiting. Rates of graft-vs-host disease were similar between both arms (midostaurin + SOC, 70%; SOC, 73%). The addition of midostaurin maintenance therapy following alloHSCT may provide clinical benefit in some patients with FLT3-ITD AML. (ClinicalTrials.gov identifier: NCT01883362).

Reduced Risk of Relapse for Total Body Irradiation + Fludarabine Compared to Busulphan + Fludarabine As “Reduced-Toxicity” Conditioning for Patients with Acute Myeloid Leukemia Treated with Allohsct in First Complete Remission. a Study By the Acute Leukemia Working Party of the EBMT

Background: Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with acute myeloid leukemia (AML) being at high risk of relapse. However, the procedure using conventional myeloablative conditioning regimens based on either busulphan (Bu) or total body irradiation (TBI) in combination with cyclophosphamide is associated with significant risk of non-relapse mortality (NRM). The use of reduced-intensity or non-myeloablative conditioning regimens results in improved tolerance but increased incidence of disease recurrence. In order to reduce toxicity while maintaining the efficacy, alternative approaches have been proposed including the use of moderately reduced doses of Bu or TBI in combination with fludarabine (Flu). The goal of this retrospective study to compare BuFlu and TBI/Flu reduced-toxicity regimens. Patients and methods: Adult patients with AML treated in CR1 with alloHSCT from either HLA-matched sibling or unrelated donor between January 2006 and June 2018 were included in the analysis. The following conditioning regimens have been selected for the comparison: intravenous Bu at a total dose 9.6 mg/kg (3 days) + Flu (Bu3Flu, N=350) or TBI at a total dose of 8 Gy + Flu (TBI8Flu, N=168). In both groups the proportion of patients with intermediate risk karyotype was 74% while high risk - 24%. The proportion of patients with secondary AML was also the same (14%). Patients in the Bu3Flu group were significantly older, were treated more frequently with alloHSCT from unrelated donors and were treated in more recent period. Results: The engraftment rate was 99% for both regimens. In a univariate analysis the use of TBI8Flu was associated with reduced incidence of relapse (20% vs. 30% at 2 years, p=0.01) and tendency to increased leukemia-free survival (LFS; 66% vs. 60%, p=0.15) and overall survival (OS; 74% vs. 58%, p=0.051) as well as reduced incidence of grade III-IV acute graft-versus-host disease (GVHD, 4% vs. 9%, p=0.03). The effects on non-relapse mortality (NRM), grade II-IV acute GVHD and chronic GVHD were not significant. In a multivariate analysis a chance of LFS was reduced for patients with high risk karyotype and secondary AML, with no effect of donor type. Due to significant interaction between type of conditioning and age, further analyses were performed stratifying patients above or below 50 years. For patients ≤50 y.o. the use of TBI8Gy was associated with reduced incidence of relapse (21% vs. 35%; Cox model: HR=0.49, p=0.049), tendency to improved NRM (4% vs. 7%,; HR=0.17; p=0.1), significantly improved LFS (75% vs. 58%, p=0.02; HR=0.45, p=0.02), improved OS (84% vs. 60%; HR=0.29, p=0.002) improved survival free from both GVHD and relapse (GRFS; 56% vs. 46%; HR=0.53, p=0.02) and reduced incidence of grade II-IV acute GVHD (15% vs. 26%; HR=0.53, p=0.02). For patients &amp;gt;50 y.o. the effect of TBI8Flu on relapse was not statistically significant (19% vs. 29%; HR=0.64, p=0.21) while this regimen was associated with increased risk of NRM (26% vs. 11%; HR=3.98, p=0.0006) leading to a tendency to decreased OS (59% vs. 63%; HR=1.53, p=0.1). Conclusion: Reduced-toxicity regimens using either TBI8Flu or Bu3Flu for patients with AML in CR1 are associated with relatively low risk of relapse and NRM leading to enhancing survival rates after alloHSCT. The use of TBI8Flu appears more effective compared to Bu3Flu and may be advised in younger patients where reduced risk of relapse translates into improved survival. In older individuals it should be used with caution due to increased risk of NRM. Prospective studies are needed to verify our findings. Disclosures Labopin: Jazz Pharmaceuticals: Honoraria. Byrne:Ariad/Incyte: Honoraria, Speakers Bureau. Beelen:Medac GmbH Wedel Germany: Consultancy, Honoraria. Blaise:Jazz Pharmaceuticals: Honoraria; Molmed: Consultancy, Honoraria; Sanofi: Honoraria; Pierre Fabre medicaments: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding.

Hyperleukocytosis is associated with distinct genetic alterations and is an independent poor-risk factor in de novo acute myeloid leukemia patients.

Acute myeloid leukemia (AML) with hyperleukocytosis (HL) is intuitively thought as a unique group with dismal prognosis. However, comprehensive studies regarding the genetic landscape and clinical outcome in this group of patients are limited. A total of 693 newly diagnosed de novo non-M3 AML patients were consecutively enrolled. We compared relevant mutations in 20 genes between AML patients with or without HL and exposed their prognostic implications. Hyperleukocytosis, defined as initial white blood cell counts above 50000/μL, occurred in 28.9% of AML patients. HL patients had higher incidences of FLT3-ITD, NPM1, DNMT3A, CEBPA, and TET2 mutations. Multivariate analysis demonstrated that HL was an independent poor prognostic factor for overall survival and disease-free survival in total patients, those with intermediate-risk cytogenetics and normal karyotype irrespective of genetic alterations. Intriguingly, HL predicted poor survival in CEBPA double mutated, NPM1+/FLT3-ITD- and NPM1-/FLT3-ITD- patients. Further, HL patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR) had a significantly longer overall survival and disease-free survival than those without allo-HSCT. Hyperleukocytosis is an independent poor prognostic factor irrespective of cytogenetics and mutation status. Allo-HSCT in first CR seems to ameliorate the poor prognostic impact of HL.

Impact of Induction Regimen and of Allogeneic Hematopoietic Cell Transplantation on the Outcome in Younger Adults Patients with Acute Myeloid Leukemia with a Monosomal Karyotype: Results from the EORTC/Gimema AML-10 and AML-12 Trials

Background. Previous studies have demonstrated that monosomal karyotype (MK) confers a particularly poor prognosis in patients with acute myeloid leukemia (AML) (Breems et al., J Clin Oncol 2008, 26:4791-7).Purpose of the study. To determine the impact of the type of remission-induction chemotherapy and the impact of having a donor on overall survival (OS) in younger (</=60 years of age) AML patients with a MK.Methods. In the EORTC/GIMEMA AML-10 trial (Mandelli et al., J Clin Oncol 2009, 27:5397-403), patients were randomized to receive either daunorubicin (DNR), mitoxantrone (MTX), or idarubicin (IDA) in addition to standard-dose cytarabine (SDAC: 10 days of 100 mg/m2 per day as continuous IV infusion) and etoposide for induction chemotherapy. In the EORTC/GIMEMA AML-12 trial, (Willemze et al., J Clin Oncol 2014, 32:219-28) patients were randomized between either SDAC or high dose cytarabine (HiDAC) (3 g/m2 every 12 hours as a 3-hour IV infusion on days 1, 3, 5, and 7) induction, both with DNR, and etoposide. In both trials, a second cycle of the same remission induction chemotherapy was administered in patients who achieved a partial remission. Patients who achieved a complete remission (CR) or a CR with incomplete counts recovery (CRi) after 1 or 2 courses of induction chemotherapy received a consolidation chemotherapy with the same anthacycline as in the induction course plus intermediate dose cytarabine. Patients in both studies were then scheduled to receive an allogeneic hematopoietic stem cell transplantation (allo-HSCT) if they had a donor or an autologous HSCT (auto-HSCT) otherwise, in first CR. For the current analyses, cytogenetics were centrally reviewed and re-classified using the European Leukemia Net (ELN) definition. MK was defined as the presence of 2 or more monosomies, or a single monosomy in the presence of structural abnormalities.Results. In the AML-10 trial, 2157 patients were randomized to receive DNR, MTX or IDA. The current analyses were performed in a subgroup of 910 patients for whom cytogenetic data were available and who did not have t(8;21), inv(16) nor t(15;17). 709 of them were classified in the ELN intermediate cytogenetic risk group and 201 in the adverse group. Out of the 910 patients, 93 had a MK. In comparison to the 817 remaining (MK-) patients, MK+ patients were less likely to achieve a CR, were more likely to have resistant disease (RD), and had worse OS and disease-free survival (DFS) (Table 1). There was no impact of the type of anthracycline on outcomes. Among the MK+ patients who achieved a CR, 5-yr OS from CR was 26% (95% CI, 10-46%) in patients with a donor (n=21, of whom, 13 received an allo-HSCT in first CR), versus 4% (95% CI, 0-18%) in those without a donor (n=24, of whom, 1 received an allo-HSCT in first CR) (P=0.07). Further, among the 10 MK+ who survived more than 1 year, 7 received an allo-HSCT in first CR (n=4) or beyond (n=3). In the AML-12 trial, 1942 patients were randomized between HiDAC or SDAC. The current analyses were performed in a subgroup of 1079 patients for whom cytogenetic data were available and who did not have t(8;21), inv(16) nor t(15;17). 893 of them were classified in the ELN intermediate cytogenetic risk group and 186 in the adverse group. Out of the 1079 patients, 98 had a MK. In comparison to the 1027 MK- patients, MK+ patients were less likely to achieve a CR, were more likely to have RD, and had worse OS and DFS (Table 1). There was a higher probability of achieving a CR and a trend for better OS in MK- patients randomized in the HiDAC arm (Table 2). In contrast, in MK+ patients, HiDAC did not increase either the CR rate as compared to SDAC, nor the 5-yr OS rate: 7% (HiDAC) vs 2% (SDAC) (Table 2). Finally, among the MK+ patients who achieved a CR, 5-yr OS from CR was 14 % (95% CI, 4-32%) in patients with a donor (n=21, of whom, 12 received an allo-HSCT in first CR), versus 4% (95% CI, 0.3-18%) in those without a donor (n=24) (P=0.60). Further, among the 4 MK+ patients who survived more than 1 year, 3 received an allo-HSCT in first CR (n=2) or beyond (n=1).Conclusions. This analysis confirms the poor prognosis of MK in younger AML patients. Shifting DNR to IDA or MTX or administration of HiDAC in the induction course failed to improve outcome of MK+ patients. Finally, there was a suggestion for a longer OS from CR in MK+ patients who had a donor, suggesting that allo-HSCT should be offered in all fit MK+ patients.FB & MSK contributed equally to this work [Display omitted] [Display omitted] DisclosuresThomas:Pfizer: Consultancy.

Pharmacodynamic Monitoring of the Efficacy of a Targeted Therapy with Midostaurin By Plasma Inhibitor Activity (PIA) Analysis in FLT3 -ITD Positive AML Patients within the AMLSG 16-10 Trial: A Study of the AML Study Group (AMLSG)

Background: Activating mutations in receptor tyrosine kinases like FLT3 (FLT3mut) lead to an aberrant signal transduction thereby causing an increased proliferation of hematopoietic cells. Internal tandem duplications (FLT3-ITD) or mutations in the tyrosine kinase domain (FLT3-TKD) occur in about 25% of younger adult patients (pts) with acute myeloid leukemia (AML), with FLT3 -ITD being associated with an unfavourable outcome. FLT3mut present an excellent target for small molecule tyrosine kinase inhibitors (TKI). The multi-targeted kinase inhibitor midostaurin (PKC412) is currently under investigation as a FLT3-inhibitor in combination with intensive chemotherapy. Monitoring of the efficacy of such a targeted therapy and correlation of the results with clinical outcome will be of major importance. The plasma inhibitor activity (PIA) assay allows the visualization of the level of dephosphorylation of the target under TKI therapy. Preliminary data suggest a correlation between the grade of dephosphorylation, as a marker for the activity of the TKI, and clinical outcome.Aims: To individually measure the level of FLT3 dephosphorylation by PIA analysis in a large cohort of FLT3-ITD AML pts treated within our AMLSG16-10 trial (NCT: NCT01477606) which combines midostaurin with intensive chemotherapy, and to correlate the results with clinical outcome.Methods: Plasma samples from pts (age 18-70 years) with newly diagnosed FLT3-ITD AML were obtained at different time points for PIA analysis. All pts were enrolled on the ongoing AMLSG 16-10 trial applying intensive therapy in combination with midostaurin (50mg twice a day). For consolidation therapy, pts proceeded to allogeneic hematopoietic stem cell transplantation (alloHSCT) as first priority; pts not eligible for alloHSCT were intended to receive 3 cycles of age-adapted high-dose cytarabine (HiDAC) in combination with midostaurin from day 6 onwards. In all pts one year of maintenance therapy with midostaurin was intended. PIA analyses were performed at defined time points (day 15 of induction, each consolidation cycle, at the end of each treatment cycle, every 3 months during maintenance therapy) as previously described (Levis MJ, et al. Blood 2006; 108:3477-83).Results: So far, PIA analyses were performed in 63 pts (median age, 51.6 years; range, 20-70 years) during (n=63) and after (n=73) first and second induction cycle, during (n=40) and after (n=53) consolidation therapy with HiDAC as well as during maintenance therapy (n=82). During and after induction therapy median levels of phosphorylated FLT3 (p-FLT3) were 46.6% (4.5-100%, <20% in 7.9%) and 39.4% (0.3-100%, <20% in 20.5%), respectively. Co-medication with azoles had no impact on p-FLT3 levels. In pts with a FLT3-ITD mutant to wildtype ratio above our recently defined cut-off value of 0.5, levels of p-FLT3 <20% were associated with a complete remission (CR)-rate of 100%, whereas in those pts with p-FLT3 levels ≥20%, 4 out of 22 pts (18%) had resistant disease. In contrast, response in pts with a mutant to wildtype ratio below 0.5 was independent of the p-FLT3 level. During and at the end of consolidation cycles as well as during maintenance therapy p-FLT3 levels in pts treated with midostaurin were 52% (14.8-100%, <20% in 5%), 63% (7.6-100%, <20% in 7.4%) and 60.2% (11.5-100%, <20% in 3.7%), respectively. In pts concomitantly treated with azoles levels of p-FLT3 were lower without reaching significance. 39 of 63 pts received alloHSCT in first CR; those pts with p-FLT3 levels <20% after induction therapy had an in trend better survival, whereas no impact of phosphorylation levels was evident in pts receiving chemotherapy alone.Conclusion: In our study of FLT3-ITD AML pts treated with midostaurin in combination with intensive chemotherapy we could show that the lowest levels of p-FLT3 were reached during and after induction therapy. In pts with a FLT3-ITD mutant to wildtype ratio >0.5, levels of p-FLT3 <20% during and after induction therapy were associated with a high CR-rate. When receiving alloHSCT these pts had an in trend better survival compared to those with p-FLT3 levels >20%. An update of the data will be presented at the meeting. DisclosuresSalwender:Celgene: Honoraria; Janssen Cilag: Honoraria; Bristol Meyer Sqibb: Honoraria; Amgen: Honoraria; Novartis: Honoraria. Horst:Amgen: Honoraria, Research Funding; Pfizer: Research Funding; Ingleheim: Research Funding; Boehringer: Research Funding; MSD: Research Funding; Gilead: Honoraria, Research Funding. Schlenk:Novartis: Honoraria, Research Funding; Boehringer-Ingelheim: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Research Funding; Teva: Honoraria, Research Funding; Arog: Honoraria, Research Funding.

Pediatric Acute Megakaryoblastic Leukemia without Down Syndrome: A Retrospective Study by the International Berlin-Frankfurt-Munster Study Group (I-BFMSG)

Acute megakaryoblastic leukemia (AMKL) comprises up to 10% of childhood acute myeloid leukemia (AML) cases. However, no large-scale studies have comprehensively evaluated the clinical characteristics and outcomes of patients with AMKL. We performed a large-scale international retrospective study of pediatric patients (diagnosed at age ≤18 years) with de novoAMKL without Down syndrome treated from 1989 to 2009.The study included 490 patients with AMKL, which comprises 7.9% of the pediatric AML patients treated by 19 members of the I-BFMSG. At diagnosis, the median age of patients was 1.5 years (range, 0.0–16.5 years), median white blood cell count was 12.0×109/L (range, 0.6–188.0×109/L), 23 (4.7%) patients showed central nervous system involvement, and both sexes were equally represented. Complete remission (CR) was achieved in 417 (85.1%) patients, and 5-year event-free (EFS) and overall survival (OS) rates were 43.7%±2.7% and 49.0%±2.7%, respectively. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed in 206 (42.0%) patients. The 5-year disease-free survival and OS rates for patients who received allo-HSCT in first CR (n=112, 56.3%±5.2%, and 57.7%±5.2%, respectively) and for those who did not receive transplantation in first CR (n=298, 50.2%±3.6% and 55.2%±3.5%) were not significantly different (P=0.12 and P=0.57).Complete cytogenetic data were available for 372 (75.9%) patients: diploid (n=49, 13.2%), hypodiploid (n=18, 4.8%), pseudodiploid (n=119, 32.0%), 47–50 chromosomes (n=142, 38.2%), and >50 chromosomes (n=44, 11.8%). Chromosome gain occurred in 195 (52.4%) patients: +21 was the most common (n=106, 28.5%), followed by +19 (n=93, 25.0%), and +8 (n=77, 20.7%). Losses occurred in 65 cases (17.5%), in the decreasing order of –7 (n=13, 3.5%), –9 (n=9, 2.4%), –13, and –15 (n=7 each, 1.9%). Structural chromosomal aberrations were observed in 278 (74.7%) patients, most commonly t(1;22) (n=51, 13.7%) and 11q23 rearrangements (n=38, 10.2%) with t(9;11) in 21 patients. Other abnormalities included 7p (n=43, 11.6%) and 13q (n=31, 8.3%; 16 with deletions) breakpoints. Patients with t(1;22) were significantly younger at diagnosis (P<0.001; median 0.6 years, range 0.0–6.3 years) and more often female (P=0.05; 64.7%) while those with –7 were significantly older (P=0.006; median 4.2 years, range 0.4–15.0 years) than those with other cytogenetic subgroups.Multiple regression analysis for EFS and OS with clinical and cytogenetic features showed that treatment period (1989–1999 vs. 2000–2009), normal cytogenetics, –7, t(9;11), 13q-, and –15 were associated with significantly worse outcomes than those for other subgroups, whereas abnormalities in 7p were associated with better outcomes (Table). Patients with –13 and 9p abnormalities other than t(9;11) had a poorer EFS and OS, respectively. Patients with +21 or t(1;22) did not show a significant difference in survival rates.This international study on the largest cohort of AMKL patients analyzed to date shows heterogeneity in cytogenetic findings and identifies some subgroups with a particularly dismal outcome. The advent of newer methods to evaluate genetic lesions can help identify therapeutic targets for improving the outcome in this subgroup of patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Can Allo-HSCT Improve the Poor Clinical Outcome of the “Internal Tandem Duplication” of the FLT3 Gene?

AML patients (pts) with a normal chromosome pattern and the “Internal Tandem Duplication” (ITD) of the FLT3 gene have an overall and event-free survival (OS, EFS) inferior than those of pts with a FLT3 “wild-type” gene because of a higher relapse risk, are placed in the intermediate-1 prognostic category, and when in complete remission (CR) are candidates to allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the role of allo-HSCT in ITD+ pts is still debated and a recent retrospective analysis has stated that FLT3/ITD adversely affected allo-HSCT outcome in the same direction as it does after chemotherapy.Thus, the present study was aimed to compare the OS, EFS and relapse risk of pts submitted to allo-HSCT in first CR or in initial relapse, defined by a 5-10% bone marrow blast cell percentage, with those of pts submitted to chemotherapy alone.The study cohort consisted of 54 chromosomally normal, ITD+ consecutive non-M3 AML pts who were included in 168 AML pts aged 18-66 years who came to our observation in the period January 2007-December 2013. At diagnosis median age was 48.6 years (range 18-66), 25 pts were males and 29 females. Median follow-up was 16.2 months (0.4-68.8): median follow-up for responsive pts was 7.15 months (range 0.26-27.6), for relapsed pts was 18.1 (range 1.9-68.8) and for transplanted pts was 9.1 months (range 2.9-26.8). All pts received the same induction treatment that consisted of standard Idarubicine+Ara-c “3+7” followed by two consolidation courses with high-dose Ara-c. Those who failed induction received other treatment schedules among which Fludarabine+Ara-c+Idarubicine was the most common. At the end of consolidation 38 pts were in first CR, achieved after 3+7 in 27 pts and after a second different course in 11. Sixteen pts had a resistant disease. After a median time of five months (range 1-21) 21/38 pts (55.2%) relapsed. All received a re-induction and 8/21 (38.1%) attained a second CR. Allo-HSCT was performed in a total of 23 pts: 12 first CRs, 6 second CRs and 5 initial relapses. The donor was a sibling in 7 pts, an unrelated donor in 13 and an haplo-identical donor in 3; the HSC source was the marrow in 6 pts, the peripheral blood in 16 and the cord blood (CB) in one. The Conditioning regimen was myeloblative (mainly Busulfan+Fludarabine) in 21 and non-myeloblative in 2; GvHD prophylaxis consisted of Cyclosporine A, steroids and methotrexate “short course”. The median number of CD34+ cells infused was 5.14x106/kg (1.3-12.7). All pts except that who received CB engrafted after a median time of 15 days (12-28); 21 were complete chimeras, two partial chimeras. Thirteen pts developed acute GvHD (grade I in 3 pts, grade II in 5, grade III in 2 and grade IV in 3) which totally/partially recovered after high dose steroids along with different immunosuppressive drugs in 4 and 9 pts respectively. Eleven pts developed a chronic GvHD which was the evolution of an aGvHD in 9, targeted different organs, was stable in 3 pts and completely/partially recovered in 4 and 2 pts respectively. Post-transplant relapse occurred in 3/12 first CRs, in none second CRs and in 3/5 initial relapse. The estimated response rate for CR pts submitted to allo-HSCT was 422.1 (95% CI: 262.4-679.1) versus 64.6 (95% CI: 40.7-102.6) for those submitted to chemotherapy alone with a median survival time of 7.2 months (range 5.3-8.8) versus not reached (1.9-not available); on univariable Cox model the HR of allo-HSCT pts was 37.9 (95% CI: 9.4-152.0) with p=0.0000. The estimated relapse rate for CR pts submitted to allo-HSCT was 8.6 (95% CI: 2.1-34.4) versus 44.3 (95% CI: 25.7-76.3) for those submitted to chemotherapy alone with a median survival time not reached (range not available) versus 13.2 (7.2-not available); on univariable Cox model the HR of allo-HSCT pts was 0.5 (95% CI: 0.2-1.1) with p=0.06. The estimated death rate for CR pts submitted to allo-HSCT was 28.7 (95% CI: 13.7-60.4) versus 49.7 (95% CI: 32.1-77.1) for those submitted to chemotherapy alone with a median survival time of 18.3 months (range 14.2-not available) versus 12.2 (8.8-18.9); on univariable Cox model the HR for allo-HSCT pts was 0.48 (95% CI: 0.2-1.1) with p=0.09.In conclusion, our series suggests that in ITD+ pts allo-HSCT significantly strengthens CR in pts who had already responded to conventional chemotherapy, but it presents only a trend towards significance when its superiority to prevent relapse was considered. DisclosuresCastagnola:Gilead Sciences: Research Funding.

T Cell–Depleted Stem Cell Transplantation for Adults with High-Risk Acute Lymphoblastic Leukemia: Long-Term Survival for Patients in First Complete Remission with a Decreased Risk of Graft-versus-Host Disease

Consolidation with allogeneic hematopoietic stem cell transplantation (allo-HSCT) provides a survival benefit to patients with acute lymphoblastic leukemia (ALL). We have previously reported comparable survival and relapse rates after T cell–depleted (TCD) allo-HSCT compared with unmodified transplantations for acute myelogenous leukemia, myelodysplastic syndrome, and non-Hodgkin lymphoma with significantly decreased graft-versus-host disease (GVHD). We performed a 56-patient retrospective study to evaluate TCD allo-HSCT for the treatment of ALL after myeloablative total body irradiation–based therapy. The 2-year and 5-year overall survival rates for patients with ALL after TCD allo-HSCT were 0.39 (95% confidence interval [CI], 0.26-0.52) and 0.32 (95% CI, 0.19-0.44), respectively, and the 2-year and 5-year disease-free survival rates were 0.38 (95% CI, 0.25-0.50) and 0.32 (95% CI, 0.20-0.44). There was a trend toward improved survival of patients who underwent TCD allo-HSCT in first complete remission compared with those who did so in other remission states. The cumulative incidence of grade II-IV acute GVHD at 1 year was 0.20 (95% CI, 0.10-0.31), and no patients developed grade IV acute GVHD. The cumulative incidence of chronic GVHD in 41 evaluable patients at 2 and 5 years was 0.15 (95% CI, 0.04-0.26), and that of extensive chronic GVHD at 2 and 5 years was 0.05 (95% CI, 0-11.6). We demonstrate OS and DFS rates that compare favorably to unmodified allo-HSCT with lower rates of GVHD.

Impact of Allogeneic Transplantation From Matched Related and Unrelated Donors on Clinical Outcome In Younger Adult AML Patients with FLT3 Internal Tandem Duplications

AbstractAbstract 909 Background:Internal tandem duplications of FLT3 (FLT3-ITD) occur in approximately one third of acute myeloid leukemia (AML) patients and are associated with poor outcome. It has been suggested that allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a matched related donor (MRD) can overcome the negative impact of FLT3-ITD. However, for those patients without MRD it is unclear, whether the adverse impact can be abrogated by allo-HSCT from a matched unrelated donor (MUD). Aims:To assess clinical outcome in AML with FLT3-ITD after allo-HSCT from MRD and MUD. Methods:The study included 437 adult patients (median age, 47 years; range, 16–60 years) with newly diagnosed, FLT3-ITD positive AML enrolled on five prospective treatment trials of the German-Austrian AML Study Group (AMLSG) between 1993 and 2008. Patients with acute promyelocytic and core binding factor leukemia were excluded. FLT3-ITD was diagnosed by genomic DNA PCR and Genescan analysis. Mutant to wild-type FLT3-ITD ratio (allelic ratio) was available in 78%, and FLT3-ITD insertion site was determined by direct sequencing in 59% of the patients.The strategy of allo-HSCT changed in November 2006. Before the amendment, only patients with MRD were intended to receive allo-HSCT in first complete remission (CR), whereas thereafter, the spectrum of donors was extended to MUD. To account for the time dependency of allo-HSCT, landmark analyses for univariable analyses and Andersen Gill models for multivariable analyses were used. Results:CR rates before and after the amendment were 72% and 68%, respectively (p=0.63). Before amendment, 71 of 234 (30%) patients received allo-HSCT (48 MRD, 23 MUD), after amendment, 58 of 77 (74%) patients (16 MRD, 42 MUD). After amendment, the cohort was characterized by a significantly higher white blood count (WBC) (p=0.002), higher allelic ratio (p=0.04) and a higher frequency of FLT3-ITD insertion site in the beta-1-sheet (p=0.05). Comparing the two cohorts before and after amendment, there was no significant difference in relapse-free survival (RFS) (p=0.51) and overall survival (OS) (p=0.45). To account for the differences in the frequencies of unfavorable prognostic markers, we performed multivariable analyses in the whole population including the following variables: age, log(WBC), allo-HSCT from MRD or MUD, NPM1 mutation and median dichotomized allelic ratio. This model revealed allo-HSCT from MRD (HR 0.64, p=0.03) and age (difference of ten years) (HR 1.19, p=0.02) as significant prognostic parameters, whereas allo-HSCT from MUD was not significant (HR 0.82, p=0.31). In subset analysis, based on the availability of FLT3-ITD insertion site, the beneficial impact of allo-HSCT from MRD (HR 0.48, p=0.02) was even more pronounced, and FLT3-ITD insertion site in the beta-1-sheet appeared as a significant variable (HR 1.67, p=0.01). Landmark analyses for RFS at five months revealed a beneficial impact of allo-HSCT from both MRD and MUD, whereas at later time points the beneficial impact of allo-HSCT from MUD disappeared. There was no significant difference in cumulative incidence of relapse (p=0.25) and death (p=0.50) between allo-HSCT from MRD and MUD. Of 167 patients who relapsed, four received allo-HSCT from a haplo-identical family donor (HID), 54 from MUD and 12 from MRD. Overall survival for relapsed patients without transplantation and those with allo-HSCT from MRD was below 10% after one year and was significantly inferior compared to patients receiving allo-HSCT from MUD or HID with 49% after one year (p<0.0001). Conclusions:Allo-HSCT from MRD and also from MUD, if performed early during first CR, improves survival of younger adult patients with FLT3-ITD positive AML. Outcome after relapse was generally very poor, with allo-HSCT from MUD or HID having a beneficial effect. Disclosures:No relevant conflicts of interest to declare.

Prospective outcome data on 267 unselected adult patients with Philadelphia chromosome–positive acute lymphoblastic leukemia confirms superiority of allogeneic transplantation over chemotherapy in the pre-imatinib era: results from the International ALL Trial MRC UKALLXII/ECOG2993

AbstractProspective data on the value of allogeneic hematopoietic stem cell transplantation (alloHSCT) in Philadelphia chromosome–positive (Ph+) acute lymphoblastic leukemia (ALL) are limited. The UKALLXII/ECOG 2993 study evaluated the outcome of assigning alloHSCT with a sibling (sib) or matched unrelated donor (MUD) to patients younger than 55 years of age achieving complete remission (CR). The CR rate of 267 patients, median age 40, was 82%. Twenty-eight percent of patients proceeded to alloHSCT in first CR. Age older than 55 years or a pre-HSCT event were the most common reasons for failure to progress to alloHSCT. At 5 years, overall survival (OS) was 44% after sib alloHSCT, 36% after MUD alloHSCT, and 19% after chemotherapy. After adjustment for sex, age, and white blood count and excluding chemotherapy-treated patients who relapsed or died before the median time to alloHSCT, only relapse-free survival remained significantly superior in the alloHSCT group (odds ratio 0.31, 95% confidence interval 0.16-0.61). An intention-to-treat analysis, using the availability or not of a matched sibling donor, showed 5-year OS to be nonsignificantly better at 34% with a donor versus 25% with no donor. This prospective trial in adult Ph+ ALL indicates a modest but significant benefit to alloHSCT. This trial has been registered with clinicaltrials.gov under identifier NCT00002514 and as ISRCTN77346223.

Philadelphia chromosome-positive acute lymphoblastic leukemia in Taiwan.

From January 1986 to December 1998, 26 (23%) of 114 acute lymphoblastic leukemia (ALL) patients older than 15 years were found to have Philadelphia (Ph) chromosome. They accounted for 28% (26 of 94) of the patients with B-lineage ALL. Compared with the other 88 ALL patients, the leukemic cells from all but one Ph-positive ALL patients were early pre-B cells with a higher rate of CD34 expression (92% vs 50%, P<0.05). At presentation, the Ph-positive adult ALL patients had higher circulating blasts (mean 21.4 vs 3.66x10(4)/microl, P<0.05) and lower initial platelet counts (mean 4.47 vs 7.34x10(4)/microl, P<0.01) and showed a trend toward higher frequency of initial central nerve system (CNS) involvement (25% vs 11%, P=0.098) than the others. Among patients with adequate chemotherapy, 16 (64%) of the 25 Ph-positive ALL patients achieved complete remission (CR), an incidence marginally lower than that of Ph-negative ALL (62 of 76, 82%, P=0.06) and significantly lower than that of Ph-negative B-lineage ALL (50 of 58, 86%, P=0.0037). However, all patients relapsed except for those who received allogeneic hemopoietic stem cell transplantation (allo-HSCT). The probabilities of 5-year continuous CR and 5-year survival for Ph-positive adult ALL patients were significantly inferior to those for Ph-negative adult ALL patients (0% vs 12%, P=0.0001, and 7% vs 19%, P=0.047, respectively), and those for Ph-negative B-lineage ALL (0% vs 14%, P<0.0001, and 7% vs 23%, P=0.002, respectively). Prognostic factors were analyzed among the Ph-positive ALL patients including the 26 adults mentioned above and an additional 11 children. No clinical or biological characteristics such as age, sex, initial circulating blast count, extramedullary involvement, or CD34 expression had an impact on the disease outcome. Allo-HSCT in first CR may improve the probability of 5-year continuous CR (100% vs. 0% for those without allo-HSCT, P=0.0091) although only three patients received it in this study. In conclusion, Ph-positive ALL patients tended to have a poor prognosis, regardless of whether other possible risk factors were present or not. Aggressive treatment, such as high-dose chemotherapy with allo-HSCT, should be considered for these patients to improve survival.