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Highlights • Major mechanisms of relapse include HLA loss, HLA down-regulation, and expression of coinhibitory ligands. • Combination of donor lymphocyte infusion with immunomodulating agents and tyrosine kinase inhibitors may enhance the graft-versus-leukemia (GVL) effect. • Immune checkpoint inhibitors can induce a significant GVL effect, but toxicity is high. ABSTRACT The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) relies mainly on the graft-versus-leukemia effect. Relapse after allo-HCT occurs in a considerable proportion of patients and has a dismal prognosis, with still very limited curative potential. This review provides an overview of the established and evolving approaches to preventing or treating relapse of AML and MDS after allo-HCT, in the context of novel insight into the biology of relapse. Established prophylactic measures to prevent relapse include optimized conditioning and graft-versus-host disease (GVHD) prophylaxis, as well as donor lymphocyte infusion (DLI) for high-risk patients; novel immunomodulatory interventions and maintenance approaches are still experimental. Improved diagnostics can detect persistent or recurring disease at a molecular level, enabling early preemptive interventions. Established options include hypomethylating agents and DLI. Standard treatments for hematologic relapse include chemotherapy, cessation of immunosuppressive treatment, and DLI. Experimental approaches include molecular targeted therapies, novel immunomodulatory treatments, and second allo-HCT. For all interventions, the potential risks, including occurrence of GVHD, must be weighed against the benefits individually in each patient. Concurrently, prevention and treatment of relapse after allo-HCT remain challenging and unmet medical needs. [ABSTRACT FROM AUTHOR]

Highlights • The impact of donor age and sex but not CMV matching is comparable with that of single HLA disparity on survival after HSCT. • Similar survival after matched unrelated and related donor HSCT for AML or MDS reflects lower NRM but higher relapse risks in the latter. Abstract Increasing donor–recipient HLA disparity is associated with negative outcomes of allogeneic hematopoietic stem cell transplantation (HSCT), but its comparative relevance amid non-HLA donor characteristics is not well established. We addressed this question in 3215 HSCTs performed between 2005 and 2013 in Germany for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Donors were HLA-matched related (MRD; n = 872) or unrelated (10/10 MUD, n = 1553) or HLA-mismatched unrelated (<10/10 MMUD, n = 790). Overall survival (OS) was similar after MRD compared with 10/10 MUD HSCT, reflecting opposing hazards of relapse (hazard ratio [HR], 1.32; P <.002) and nonrelapse mortality (HR,.63; P <.001). After UD HSCT, increasing HLA disparity was associated with inferior OS (HR, 1.21 [ P <.02] and HR, 1.57 [ P <.001] for 9/10 and ≤8/10 MMUD, respectively, compared with 10/10 MUD). Among non-HLA donor characteristics, age, sex mismatching (male recipient–female donor), and cytomegalovirus (CMV) mismatching (positive recipient–negative donor) impacted OS. Multivariate subgroup analysis showed that OS was similar after HSCT from the youngest 9/10 MMUD (<30 years) compared with the oldest 10/10 MUD (>40 years) (HR, 1.18; P =.25) and also in male patients transplanted from female 10/10 MUD compared with male 9/10 MMUD (HR,.89; P =.46). In contrast, OS of CMV-positive patients tended to be better with CMV-negative 10/10 MUDs compared with CMV-positive 9/10 MMUDs (HR, 1.31; P =.04). Because of low patient numbers in subgroups, definite conclusions and establishment of a hierarchy among HLA matching and non-HLA donor characteristics could not be made. Our data suggest that the impact of donor age and sex mismatch but not CMV mismatch on outcome of allogeneic HSCT may be comparable with that of single HLA disparity. [ABSTRACT FROM AUTHOR]

Background Allogeneic hematopoietic stem cell transplantation (HCT) remains a challenge in elderly and comorbid AML and MDS patients. This patient population is at increased risk for non-relapse mortality (NRM) when treated with standard myeloablative conditioning and was selected to compare a newly developed treosulfan-based with a well-established reduced intensity busulfan-based preparative regimen in a prospective randomized clinical phase III trial. Methods Adult patients with AML in remission or MDS scheduled for HCT from matched related or unrelated donors, aged ≥50 years or with a comorbidity index (HCT-CI) of >2 were enrolled by a central stratified randomization procedure. Treatment arms consisted of intravenous (IV) treosulfan (10 g/m²/day [d-4 to d-2]) or IV busulfan (3.2 mg/kg/day [d-4 to d-3]), both combined with IV fludarabine (30 mg/m²/day [d-6 to d-2]). The primary objective was to compare event-free survival (EFS) at two years with relapse/progression of disease, graft failure, or death reported as events. Secondary endpoints were safety evaluation (according to CTCAE v4.03), engraftment, chimerism, overall survival (OS), relapse/progression incidence (RI), NRM and acute or chronic GvHD. After a previously conducted confirmatory interim analysis (based on 476 patients), which resulted in early termination of patient accrual due to significant non-inferiority of treosulfan treatment with improved EFS, NRM and OS (Beelen et al., ASH 2017), results of the final analysis of all 570 randomized patients including post surveillance data are provided here. Results Median age of the 551 patients (352 AML; 199 MDS) included in the full analysis set (268 treosulfan; 283 busulfan) was 60 years (range: 31, 70). Frequencies of early adverse events (d-6 to d+28) and incidences of acute and chronic GvHD were largely comparable between the two regimens, while extensive chronic GvHD was numerically in favor of treosulfan (19.7% vs. 26.7%; p=0.0750). Primary neutrophil recovery at day +28 was comparable, while the rate of complete donor-type chimerism (day +28) was higher after treosulfan (93.2% vs. 83.3%; p<0.0001). After a median follow-up of 29 months (range: 3.0, 54.3) the 2-year EFS was significantly higher in the treosulfan arm (65.7% vs. 51.2%; hazard ratio [HR] 0.64; p=0.0012) as was OS (72.7% vs. 60.2%; HR 0.64; p=0.0037) and NRM (12.0% vs. 20.4%; HR 0.63; p=0.0343). RI was comparable between both regimens (22.0% vs. 25.2%; HR 0.82; p=0.2631). Results were consistent within all pre-defined major prognostic subgroups of patients. Conclusions Final evaluation of this phase III trial substantiates the previous confirmatory analysis resulting in significantly improved survival after treosulfan-based conditioning. Due to the reduction of NRM a major clinical benefit of the new treosulfan conditioning regimen was demonstrated in the selected AML/MDS patient population. [ABSTRACT FROM AUTHOR]

• Allotransplant for myelodysplastic syndrome is limited by high nonrelapse mortality. • Comorbidities assessed by the original Sorror score impact mortality negatively. • Chronological age also continues to play an independent prognostic role on mortality. • Both age and comorbidities should be integrated in the allotransplant decision process. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only potentially curative option for myelodysplastic syndromes (MDSs) but is severely limited by nonrelapse mortality (NRM), especially in this mostly older population. Comorbidity assessment is crucial to predict NRM and often assessed with the Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI). Moreover, the impact of age on NRM still remains a matter of debate. In recent years, the age at which transplants are made has been progressively increasing, and patients with comorbidities have become more common. Extricating the respective roles of age and comorbidities in toxic mortality is all the more important. This study by the European Group for Blood and Marrow Transplantation registry included 1245 adult patients who underwent a first allogeneic stem cell transplantation for MDSs between 2003 and 2014. Overall, 4-year NRM and overall survival were 32% and 47%, respectively. When considered as continuous predictors, HCT-CI score and age were associated with an increased hazard ratio (HR) for NRM. In multivariate analysis, age band (HR, 1.13; 95% CI, 1.02 to 1.25; P =.016), HCT-CI ≥3 (HR, 1.34; 95% CI, 1.04 to 1.73; P =.022), and Karnofsky Performance Status ≤80 (HR, 2.03; 95% CI, 1.52 to 2.73; P <.0001) were significantly predictive of a worse NRM. In our large cohort, both comorbidities, evaluated by the original HCT-CI score, and chronological age significantly affected NRM. Thus, age should be part of the transplant decision-making process and should be integrated in future scoring systems predicting outcomes of HSCT in MDSs. [ABSTRACT FROM AUTHOR]

• In this largest cohort of myelofibrosis transplants analyzed to date, no significant difference in 5-year probabilities of overall survival (OS) was noted between those undergoing myeloablative conditioning (MAC) (53.0%; 95% confidence interval [CI], 49.1% to 56.9%) and reduced-intensity conditioning (RIC) (51.0%; 95% CI, 48.3% to 53.7%); P =.78. • Graft failure rates appeared higher in those undergoing RIC protocols compared with MAC protocols. • MAC platforms demonstrated a trend toward less relapse and significantly improved graft-versus-host disease-free/relapse-free survival, although this requires validation. This retrospective study by the European Society for Blood and Marrow Transplantation analyzed the outcome of 2224 patients with myelofibrosis (MF) who underwent allogeneic stem cell transplantation (allo-SCT) between 2000 and 2014; 781 (35%) underwent myeloablative conditioning (MAC) and 1443 (65%) reduced-intensity conditioning (RIC). Median patient age was 52.9 years (range, 18 to 74 years) and 57.5 years (range, 21 to 76 years) in the MAC and RIC cohorts, respectively. Donor type was similar: matched sibling donors (MAC, 317 [41%]; RIC, 552 [38%]) and unrelated donors (MAC, 464 [59%]; RIC, 891 [62%]). Median time to both neutrophil and platelet (>20 × 109/L) engraftment did not differ between cohorts. Rates of grade II to IV acute GVHD were 28% (MAC) and 31% (RIC; P = NS). Cumulative chronic GVHD rates (limited/extensive) were 22%/27% (MAC) and 19%/31% (RIC; P =.10). Cumulative incidences of nonrelapse mortality (NRM) at 1, 3, and 5 years were 25.5%, 32.2%, and 34.6% (MAC) and 26.3%, 32.8%, and 34.4% (RIC), respectively. There was a trend toward a higher relapse rate with RIC regimens compared with MAC (P =.08); rates at 1, 3, and 5 years were 10.9%, 17.2%, and 20.1% (MAC) and 14%, 19.7%, and 23.2% (RIC), respectively. No significant difference in 5-year probabilities of overall survival (OS) was noted: MAC (53.0%; 95% confidence interval [CI], 49.1% to 56.9%) and RIC (51.0%; 95% CI, 48.3% to 53.7%); P =.78. Regarding the composite end point of GVHD-free/relapse-free survival (GRFS), the unadjusted Kaplan-Meier estimate of 5-year GRFS was 32.4% (95% CI, 29.0% to 36.1%) in the MAC group and 26.1% (95% CI, 23.9% to 28.2%) in the RIC group (P =.001). In the MAC cohort, multivariable analysis confirmed worse OS and NRM with older age (>50 years), using an unrelated donor and a Karnofsky Performance Status of 80 or less. For the RIC cohort, worse OS and NRM were associated with age 60 to 70 years compared with younger recipients, use of a mismatched donor, and poor performance status. In conclusion, although similar OS rates existed for both cohorts overall, this study suggests that MAC should still be used for younger individuals suitable for such an approach due to a trend toward less relapse and an overall suggested advantage of improved GRFS, albeit this should be examined in a more homogeneous cohort. RIC allo-SCT still offers significant survival advantage in the older, fitter MF allograft patient, and optimization to reduce significant relapse and NRM rates is required. [ABSTRACT FROM AUTHOR]

• Marked improvement has been achieved in recent years in stem cell transplantation (SCT) from unrelated donors. • Long-term outcome is equivalent after SCT from unrelated and sibling donors. • Patients who are leukemia-free 2 years after SCT can expect a favorable outcome. Allogeneic stem cell transplantation (SCT) is potentially curative therapy in acute myeloid leukemia (AML). Marked improvement has been achieved with SCT from matched unrelated donors (MUDs) in recent years. However, there are limited data comparing the long-term outcomes (beyond 10 years) after SCT from sibling donors and MUDs in older patients with AML. We analyzed these outcomes in a large cohort of patients with AML (n = 1134), age ≥50 years, who were alive and leukemia-free 2 years after SCT from matched siblings (n = 848) or MUDs (n = 286), with a median follow-up of 8.9 years. The median age was 56 and 58 years after SCT from siblings and MUDs, respectively (P =.005). In the sibling group, 77%, 12%, and 11% were in first complete remission (CR1), second complete remission (CR2), and active leukemia at SCT compared with 50%, 25%, and 25% in the MUD group, respectively (P <.001). Sixty-one percent of siblings and 62% of MUDs had reduced-intensity conditioning (P =.78). The 10-year leukemia-free survival (LFS) of patients surviving leukemia-free 2 years after SCT was 72% and 62%, respectively (P =.30). Multivariate analysis identified active leukemia at SCT (hazard ratio [HR], 1.86; P =.0001) or CR2 (HR, 1.51; P =.02) compared with CR1, female recipients (HR, 0.71; P =.006), adverse cytogenetics (HR, 2.52; P =.01), and prior graft-versus-host disease (HR, 1.31; P =.04) as independent factors predicting LFS. Donor and conditioning type were not significant. The cumulative incidence was 15% and 17% (P =.97) for late relapse mortality and 13% and 21% for late nonrelapse mortality, respectively (P =.15). In conclusion, long-term LFS is similar, and patients who are leukemia-free 2 years after SCT can expect favorable outcomes with both donor types. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (HSCT) recipients frequently develop acute respiratory failure (ARF) with pulmonary infiltrates. Molecular- and biomarker-based assays enhance pathogen detection, but data on their yield in this population are scarce. This was a retrospective single-center study of 156 consecutive HSCT recipients admitted to the intensive care unit (ICU) between May 2013 and July 2017. Findings from a microbiologic diagnostic workup using currently available methods on bronchoalveolar lavage (BAL) and blood samples from 66 patients (age, 58 years [range, 45 to 64]; HSCT to ICU, 176 days [range, 85 to 407]) with ARF and pulmonary infiltrates were analyzed. In 47 patients (71%) a causative pathogen was identified (fungal, n = 28; viral, n = 26; bacterial, n = 18). Polymicrobial findings involving several pathogen groups occurred in 20 patients (30%). Culture (12/16, 75%), galactomannan (13/15, 87%), and Aspergillus -PCR (8/9, 89%) from BAL but not serum galactomannan (6/14, 43%) helped to diagnose invasive aspergillosis (n = 16, 24%). Aspergillus -PCR detected azole resistance in 2 cases. Mucorales was found in 7 patients (11%; BAL culture, n = 6; Mucorales-PCR, n = 1). Patients with identified pathogens had higher Simplified Acute Physiology Score II scores ( P  = .049) and inferior ICU survival (6% versus 37%, P  < .01), which largely related to the presence of an invasive fungal infection. Eight patients (12%) had 1 or more viruses with uncertain lung pathogenicity as the sole microbiologic finding. A diagnostic microbiologic workup incorporating molecular- and biomarker-based assays identified pathogens in most HSCT recipients with ARF and pulmonary infiltrates admitted to the ICU. Implications of polymicrobial infection and pathogen patterns in these patients warrant further investigation. [ABSTRACT FROM AUTHOR]

Dose intensity of the conditioning regimen has significant impact on the outcomes after stem cell transplantation (SCT) for acute myeloid leukemia. Most studies have shown more relapse, less nonrelapse mortality (NRM), and similar overall survival after reduced-intensity and myeloablative conditioning. There are limited data on the dose equivalence and expected outcomes of treosulfan-based compared with busulfan-based conditioning. We compared SCT outcomes after fludarabine with either intravenous busulfan at a myeloablative dose (FB4, 12.8 mg/kg, n = 1265) or a reduced dose (FB2, 6.4 mg/kg, n = 1456) or treosulfan at 42 g/m 2 (FT14, n = 403) or 36 g/m 2 (FT12, n = 168). Median patient age was 48, 60, 57, and 60 years in the FB4, FB2, FT14, and FT12 groups, respectively ( P  < .0001). Two-year overall survival was 58%, 53%, 53%, and 51%, respectively ( P  = .25). Multivariate analysis identified advanced age, advanced disease status, and secondary leukemia to be associated with worse survival. Relapse rate was 30%, 35%, 34%, and 40%, respectively. Relapse was more common after FB2, advanced age and disease status, secondary leukemia, and sibling donors. NRM was 17%, 18%, 21%, and 16%, respectively. NRM was least common after FT12 and more common with advanced age and disease status and unrelated donors. Treosulfan-based regimens were associated with lower rates of graft-versus-host disease. There was no difference in any outcome among patients in first complete remission at transplantation. However, there was better survival with treosulfan-based conditioning in advanced leukemia. In conclusion, survival is determined mostly by disease biology and is similar after various regimens. Treosulfan-based conditioning is more similar to myeloablative than to reduced-intensity conditioning but can be administered safely in older patients, with lower rates of graft-versus-host disease and possibly better outcomes in patients with active leukemia. [ABSTRACT FROM AUTHOR]

The deletion (5q) karyotype (del [5q]) in patients with myelodysplastic syndrome (MDS) is the most common karyotypic abnormality in de novo MDS. An increased number of blasts and additional karyotypic abnormalities (del [5q]+) are associated with a poor outcome. We analyzed the outcome of allogeneic hematopoietic cell transplants (HCT) in patients suffering from MDS with only del (5q) or del (5q)+ . A total of 162 patients, of median age 54 years (range, 9 to 73), having MDS and del (5q) abnormalities received HCT from identical siblings (n = 87) or unrelated donors (n = 75). The cumulative incidence of nonrelapse mortality and relapse incidence at 4 years was 29% (95% CI, 22 to 36) and 46% (95% CI, 38 to 54), whereas the estimated 4 year survival, relapse-free and overall, was 25% (95% CI, 18 to 33) and 30% (95% CI, 23 to 38), respectively. In a multivariate analysis patients with del (5q) and a blast excess displayed poorer survival (hazard ratio, 2.38; 95% CI, 1.44 to 3.93; P  < .001), whereas female recipient sex resulted in improved survival (hazard ratio, .61; 95% CI, .41 to .90; P  = .01). We conclude that allogeneic HCT can cure a subset of patients with MDS and a del (5q) abnormality. [ABSTRACT FROM AUTHOR]

Although quantitative PCR (qPCR) has been explored for chimerism monitoring after allogeneic stem cell transplantation (SCT), evidence regarding its clinical utility compared with standard short tandem repeat (STR) is still limited. We retrospectively studied commercial qPCR and STR chimerism with respective positivity thresholds of .1% and 1% in 359 peripheral blood (PB) and 95 bone marrow (BM) samples from 30 adult patients after first HLA-matched SCT for myeloid malignancies or acute lymphatic leukemia. Concordance between the 2 methods was 79.5%, with all discordant samples positive in qPCR but negative in STR. Of the latter, sporadic qPCR positivity without clinical correlates was seen mostly in BM samples early post-transplant. In 7 of 21 patients with available follow-up samples in the first months after transplantation, qPCR but not STR revealed low levels (<1%) of sustained host chimerism in PB, reflecting delayed engraftment or persistent mixed chimerism (PMC). These conditions were associated with donor–recipient cytomegalovirus (CMV) serostatus and early CMV reactivation but not with immunosuppressive regimens or clinical outcome. qPCR predicted all 8/8 relapses with samples in the 6 months before onset by sustained positivity in both PB and BM compared with 1/8 relapses predicted by STR mainly in BM. The response kinetics to donor lymphocyte infusions for the treatment of PMC or relapse was shown by qPCR but not STR to be protracted over several months in 3 patients. Our results demonstrate the superior clinical utility of qPCR compared with STR for monitoring subtle changes of host chimerism associated with different clinical conditions, making a case for its use in the clinical follow-up of transplant patients. [ABSTRACT FROM AUTHOR]

In this retrospective analysis we evaluated the outcome of 313 patients aged ≥ 70 years in the registry of the European Group for Blood and Marrow Transplantation with myelodysplastic syndrome (MDS; n = 221) and secondary acute myeloid leukemia (n = 92) who underwent allogeneic hematopoietic stem cell transplantation (HSCT) from related (n = 79) or unrelated (n = 234) donors. Median age at HSCT was 72 years (range, 70 to 78). Conditioning regimen was nonmyeloablative (n = 54), reduced intensity (n = 207), or standard intensity (n = 52). Allogeneic HSCT for MDS patients ≥ 70 years was increasingly performed over time. Although during 2000 to 2004 only 16 patients received HSCT, during 2011 to 2013 the number of transplantations increased to 181. The cumulative incidence of nonrelapse mortality at 1 year and relapse at 3 years was 32% and 28%, respectively, with a 3-year overall survival rate of 34%. Good performance, determined by Karnofsky performance status, and recipients' seronegativity for cytomegalovirus was associated with 3-year estimated overall survival rates of 43% ( P  = .01) and 46% ( P  = .002), respectively. Conditioning intensity did not impact survival. After careful patient selection, allogeneic HSCT can be offered to patients older than 70 years with MDS. [ABSTRACT FROM AUTHOR]

Standard first-line therapy for older patients with high-risk myelodysplastic syndrome (MDS) includes hypomethylating agents, such as azacitidine (AZA). However, the only approach with curative potential remains allogeneic hematopoietic cell transplantation (HCT). To date, no direct comparison of both strategies has been reported. The outcomes of 2 well-balanced cohorts of patients with high-risk MDS defined by age (60-70 years), performance status (Eastern Cooperative Oncology Group score ≤2), and donor availability (yes/no) were compared, including 103 patients undergoing HCT and 75 patients without this option who received AZA. The estimated 2-year overall survival after the start of treatment was 39% (95% confidence interval, 30%-50%) for the patients undergoing HCT and 23% (95% confidence interval, 14%-40%) for the patients receiving AZA therapy. In a multivariate Cox regression analysis of all patients (n = 178), Eastern Cooperative Oncology Group score (0 versus 1 versus 2; hazard ratio [HR], 2.9/3.9; P <  .001), cytogenetics (good versus intermediate versus poor; HR, 1.2/1.7; P = .026), and treatment (HCT versus AZA; HR, 0.3; P = .007) were associated with overall survival. This retrospective cohort analysis suggests a survival advantage for allogeneic HCT compared with AZA therapy in medically fit patients with high-risk MDS age 60-70 years. Prospective controlled studies are warranted. [ABSTRACT FROM AUTHOR]

Relapse of acute myelogenous leukemia has been associated with clonal cytogenetic evolution, but no study focused specifically on relapse after allogeneic hematopoietic stem cell transplantation (HSCT). We compared karyotypes in 160 patients at both diagnosis and relapse either after allo-HSCT (n = 26) or standard chemotherapy (n = 134) using chromosome banding analysis combined with fluorescein in situ hybridization. There were 71 females and 89 males (19.7-80.6 years). At diagnosis, aberrant karyotypes were more frequent in the HSCT than in the chemotherapy cohort (16 of 26; 61.5% versus 63 of 134; 47.0%). This was most obvious in patients with unfavorable cytogenetics (8 of 26; 30.8% versus 19 of 134; 14.2%; P = .032). Differences in the karyotypes between diagnosis and relapse were more frequent in the allo-cohort (14 of 26; 53.8% versus 49 of 134; 36.6%) than in the conventional cohort (n.s.), mainly because of newly emerging cytogenetic alterations. Appearance of ≥3 new clonal alterations was more frequent in the allo-cohort (6 of 12; 50.0% with clonal evolution versus 5 of 41; 12.2%, P = .005). The mean number of cytogenetic alterations per patient was increasing from 2.0 at diagnosis to 4.0 at relapse in the allo-cohort, in the conventionally treated patients from 0.9 to 1.3 (both P < .001). Thus, higher frequencies of clonal evolution and increasing cytogenetic complexity were observed in the stem cell recipients probably related to the more unfavorable cytogenetic profiles already depicted at diagnosis. [Copyright &y& Elsevier]

Acute myeloid leukemia bearing a RUNX1 gene mutation (RUNX1 + AML) has been proposed as a provisional entity in the 2016 WHO classification. Clinically, it has been associated with inferior response rates and outcome after conventional chemotherapy. Accordingly, RUNX1 + AML is allocated in the unfavorable prognostic category of the 2017 European Leukemia Net classification. Following allogeneic stem cell transplantation (alloSCT), RUNX1 was an unfavorable factor in one study in MDS/secondary AML, while data in de novo AML are scarce. Here, we present a retrospective study by the EBMT Acute Leukemia Working Party, aiming to elucidate the prognostic value of RUNX1 mutation in patients undergoing alloSCT for AML in first complete remission (CR1). Adults undergoing alloSCT for AML in CR1 from matched related or unrelated donors between 2013 and 2018 with complete information on conventional cytogenetics and RUNX1 mutational status were selected from the EBMT registry. Variables of interest were overall and leukemia-free survival (OS/LFS), GvHD/relapse free survival (GRFS), cumulative relapse incidence (RI), non-relapse mortality (NRM) and GvHD. Log rank test, Gray test and Cox regression models were used. 128 RUNX+ and 388 RUNX- patients were identified, >80% of both subgroups presenting as de novo AML. As expected, RUNX1+ patients rarely had co-mutations in NPM1 (6% vs. 26%, p=10−3), and showed a positive correlation with ASXL1 mutations (50% vs. 16%, p=10−4). Cytogenetic categories and other mutations (FLT3 -ITD, CEBPA) were equally distributed between the two groups, as were age, donor and graft type, CMV, conditioning and T cell depletion (TCD). Median follow-up was 16.4 (RUNX+) and 19.8 (RUNX-) months. 2y OS/LFS of the entire cohort were 64% [59-69]/57% [52-62], with no difference between RUNX1 + and RUNX1 - patients either in univariate or multivariate analysis (2y OS: 67.9% [57.3-78.5] vs. 63.1%v[57.4-68.7]p=0.15; 2y LFS: 57.6% [46.4-68.7] vs. 57% [51.4-62.6], p=0.38], figure 1). RUNX1 mutation neither had any impact among patients with normal karyotype (figure 2). Similarly, no other outcome parameter was influenced by RUNX1 mutational status. Instead, multivariate analysis revealed age and donor type as risk factors for OS, LFS and NRM. Poor cytogenetic was associated with higher RI and inferior LFS/GRFS, in vivo TCD with a lower rate of aGvHD II-IV, cGvHD, and better GRFS. Among patients with available information, FLT3 -ITD was an independent risk factor for relapse, LFS and GRFS. RUNX1 did not modify the role of FLT3 -ITD. Within the limits of a retrospective registry analysis, we could not find a negative influence of RUNX1 mutation on outcome after allogeneic SCT in CR1. Hence, transplantation in CR1 might overcome the unfavorable prognostic value of RUNX1 mutation and can be recommended as consolidation treatment in this entity. [ABSTRACT FROM AUTHOR]

Abstract: Transformed acute myeloid leukemia in myelofibrosis results in a median survival of less than 5 months. We identified 46 of 1048 myelofibrosis patients in the European Group for Blood and Marrow Transplantation registry who received allogeneic stem cell transplantation for acute leukemia evolving from myelofibrosis. The cumulative incidence of treatment-related mortality at 1 year was 28% (95% confidence interval, 14 to 42) and of relapse at 3 years was 47% (95% confidence interval, 31 to 63). The 3-year progression-free (PFS) and overall survival (OS) rates were 26% and 33%, respectively. The only significant factor for survival was complete remission versus no complete remission before transplantation (69% versus 22%, P = .008); however, complete remission was achieved only in 8 patients. Allogeneic stem cell transplantation can cure myelofibrosis patients transformed to leukemia. [Copyright &y& Elsevier]

Background The Dynamic International Prognostic Scoring System (DIPSS) is commonly applied to predict survival among patients with primary myelofibrosis (PMF) but has been shown to perform less precisely in secondary myelofibrosis (SMF) and after transplantation. Furthermore, the prognostic relevance of mutation profile resulted in the mutation-enhanced IPSS (MIPSS70) in PMF, as well as in a model specific to SMF (MYSEC-PM). We aimed to develop a comprehensive clinical-molecular prognostic scoring system to determine outcome for myelofibrosis undergoing allogeneic stem cell transplantation. Patients and Methods We examined 361 myelofibrosis patients, of whom 260 had PMF and 101 SMF at time of transplantation. A training cohort of 205 patients was used to create a clinical-molecular transplant scoring system (MTSS) predicting survival from Cox models, internally validated by use of bootstrap and cross-validation. Model discrimination was measured by the concordance index (C). The final MTSS was externally validated in a cohort of 156 patients and was furthermore applied to posttransplant non-relapse mortality as a secondary objective. Results Multivariable analysis on 5-year survival identified age ≥57 years, Karnofsky performance status <90%, platelet count <150 × 109/L and leukocyte count >25 × 109/L at time of transplantation, HLA-mismatched unrelated donor, ASXL1 mutated and CALR -/ MPL -unmutated genotype being independent prognostic factors for outcome. The uncorrected concordance index for the final survival model was 0.723 (95% CI, 0.713-0.733), and bias-corrected indices were similar. A weighted score of 2 was assigned to transplantation from an HLA-mismatched unrelated donor and an CALR -/ MPL -unmutated genotype, whereas a score of 1 was assigned to older age, leukocytosis, thrombocytopenia, ASXL1 mutation, and poor performance status. The MTSS consisted of four distinct risk groups showing 5-year survival in the validation cohort of 83% (95% CI, 71-95%) for low (score 0-2), 64% (95% CI, 53-75%) for intermediate (score 3-4), 37% (95% CI, 17-57%) for high (score 5), and 22% (95% CI, 4-39%) for very high risk (score >5), respectively (P<0.001). Increasing score was predictive of non-relapse mortality (P<0.001) and remained applicable to PMF (C=0.718) and SMF (C=0.701) improving prognostic ability in comparison to current systems such as DIPSS (C=0.573), DIPSS-plus (C=0.557), MIPSS70 (C=0.587), MIPSS70-plus (C=0.547), as well as MYSEC-PM (C=0.605). Conclusion The MTSS integrates clinical, molecular as well as transplant-specific risk factors that independently affected survival. We show here that this internally and externally validated system accurately discriminated different risk for death and may improve counseling compared with currently existing systems, as well as facilitate design of clinical trials in the transplant setting. [ABSTRACT FROM AUTHOR]

Allogeneic stem cell transplantation (SCT) is potentially curative therapy for patients with MDS. Prior studies have shown no overall-survival (OS) advantage of any conditioning regimen over the others. Reduced-intensity conditioning (RIC) is usually associated with lower non-relapse mortality (NRM) compared to myeloablative conditioning (MAC), however, relapse rates are higher, resulting in similar OS. Fludarabine and treosulfan (FT) is a reduced-toxicity regimen with intense anti leukemia activity in patients with myeloid malignancies. We explored outcomes following FT conditioning in comparison with other regimens. We retrospectively analyzed SCT outcomes of MDS patients reported to the chronic malignancies working party of EBMT (n=1722). The conditioning regimens were defined according to standard EBMT criteria and included FT (n=367), RIC (n=687) or MAC (n=668). FT and RIC recipients were older than MAC recipients, median age 59, 59 and 51 years, respectively (P < 0.001). More FT recipients had untreated MDS at SCT, 45%, 26% and 36%, respectively (P < 0.001). Disease status at diagnosis, cytogenetics, secondary origin and prior transformation to AML, were not different between the regimens. With a median follow-up of 20 months (1-171), 807 patients are alive, 328 died of relapse and 587 had NRM. The 5-year rates of relapse, NRM and OS for the entire group were 21% (95%CI, 19-23), 35% (95%CI, 33-38) and 44% (95%CI, 42-437), respectively. Relapse rates were similar after FT and MAC, 16% (13-21) and 19% (16-22), respectively, significantly lower than after RIC, 25% (21-28) (P = 0.003). Multivariate analysis (MVA) identified age >55 years (HR 1.42), advanced histology (RAEB 1/2, HR 2.01/ 1.73), prior transformation to AML (HR 1.87), refractory disease to prior therapies (HR 1.75) secondary origin (HR 1.33) and poor cytogenetics (HR 2.83) as associated with higher relapse risk. FT conditioning was associated with a lower risk (HR 0.63, P = 0.006). NRM was lower after FT and RIC than after MAC, 34% (29-39), 33% (30-37) and 38% (35-40), respectively (P = 0.05). MVA identified age >55 years (HR 1.39) and MAC (HR 1.34) as associated with higher NRM, while SCT from sibling donor (HR 0.81) and in CR (HR 0.80) were associated with a lower risk. In all, 5-year OS was 50% (44-55), 43% (38-47), and 43% (39-47), after FT, RIC and MAC, respectively (Figure 1, P = 0.03). MVA identified age >55 years (HR 1.39), advanced histology (RAEB 1/2, HR 1.35/ 1.10), prior transformation to AML (HR 1.37), and poor cytogenetics (HR 1.58) as associated with lower OS. FT conditioning was associated with better OS (HR 0.79, P = 0.01). FT is associated with similar low relapse rates as MAC and similar low NRM as RIC, resulting in improved outcome over both RIC and MAC. FT might be the preferred regimen for SCT in MDS. These observations merit further study in randomized prospective trials. [ABSTRACT FROM AUTHOR]

Background Acute myeloid leukemia (AML) secondary to another haematological neoplasia or malignant disease (sAML) is thought to have an inferior prognosis than de novo AML. However, the role of this difference for allogeneic stem cell transplantation (SCT) is unclear. A registry-based analysis was performed to compare results after SCT for sAML versus AML. Methods Inclusion criteria were age ≥18y and SCT for de novo or sAML from a matched related, unrelated or T-cell replete haploidentical donor between 2000 and 2016. A multivariate Cox model was performed for risk factors for outcome. It was stratified for different stages at SCT. Further, a matched pair analysis of de novo versus sAML was done, using age (+/-3 years), stage at SCT, Karnofsky performance score (KPS), conditioning, in vivo/ex vivo T cell depletion, donor, donor/recipient sex and CMV-status combination, cytogenetics, and graft source as matching criteria. Results 11439 patients (pts) with de novo and 1325 with sAML were identified. Median follow-up was 36 and 33 months. After SCT in first complete remission (CR1), 3Y cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 28.5%/16.4% for de novo (n=7691), and 35%/23.4% for sAML (n=909). 3Y overall survival (OS), leukemia-free survival (LFS) and GvHD/relapse free survival (GRFS) were 60.8%, 55.1% and 38.6% for de novo and 46.7%, 41.6% and 28.4% for sAML. In a multivariate Cox model focusing on SCT in CR1, sAML was associated with higher NRM (HR=1.32; p<10−5) and CIR (HR=1.28; p=0.0002), and lower LFS (HR=1.30; p<10−5), OS (HR=1.32; p<10−5) and GRFS (HR=1.20; p<10−5). Other factors for OS were age (p=<10-5), cytogenetics (intermediate, p=0.002, poor, p=<10-5), patient/donor sex combination (female/male, p=<10-5), KPS (<>80, p=0.003) and donor (UD 10/10 match, p=0.007; UD 9/10 match, p=10-5; haplo, p=0.002). When focusing on pts transplanted for primary refractory (de novo, n=607, sAML, n=199) or relapsed AML (de novo, n=1009, sAML, n=124), results were generally inferior. However, Cox models did not identify sAML as a relevant factor. Instead, outcome was determined by age, cytogenetics and KPS. The matched pair analysis was performed on 877 pairs and confirmed the above findings: Over all, sAML was associated with higher NRM (p=0.004), and lower LFS (p=0.004), OS (p=0.008) and GRFS (p=0.04). However, when the analysis was stratified by stage at SCT, again differences were only seen among pts transplanted in CR1, but not after SCT in advanced disease. Conclusion Our large-scale, registry-based analysis identified sAML as independent risk factor for outcome after SCT in first CR1. In primary refractory and relapsed AML, other factors such as age, cytogenetics and performance status were of higher relevance. This data may help to improve risk stratification and prognostic estimates after SCT for sAML. [ABSTRACT FROM AUTHOR]

Assessment of measurable residual disease (MRD) is rapidly transforming the therapeutic and prognostic landscape of a wide range of hematological malignancies. Its prognostic value in acute lymphoblastic leukemia (ALL) has been established and MRD measured at the end of induction is increasingly used to guide further therapy. Although MRD detectable immediately before allogeneic hematopoietic cell transplantation (HCT) is known to be associated with poor outcomes, it is unclear if or to what extent this differs with different types of conditioning. Therefore, in this retrospective multicenter study we explored if MRD detectable before allogeneic HCT for ALL is associated with different outcomes in recipients of myeloablative TBI-based versus chemotherapy-based conditioning. We analyzed outcomes of 2780 patients (median age 38 years, range 18-72) who underwent first HCT in complete remission between 2000 and 2017 using sibling or unrelated 9/10 or 10/10 matched donors. In 1816 of these patients no disease was detectable before transplantation and in 964 patients MRD was detectable (MRD positivity). Conditioning was TBI-based in 2122 (76%) transplants. In the whole cohort MRD positivity was a significant independent factor for lower overall survival (OS) and leukemia-free survival (LFS), and for higher relapse incidence (RI), with respective hazard ratios (HR, 95% confidence intervals) of 1.19 (1.02-1.39), 1.26 (1.1-1.44), 1.51 (1.26-1.8). TBI was associated with a better OS, LFS and RI with HR of 0.75 (0.62-0.90), 0.70 (0.60-0.82) and 0.60 (0.49-0.74), respectively. No significant interaction was found between MRD status and conditioning. When investigating the impact of MRD separately in the TBI and chemotherapy-based conditioning cohorts by multivariate analysis, we found MRD positivity to be associated with lower OS (HR 1.26, 1.05-1.51) and LFS (HR 1.3,1.1-1.53), and higher RI (HR 1.53, 1.23-1.9) in the TBI group, and with higher RI (HR 1.58, 1.13-2.21) in the chemotherapy group. There was no significant association between MRD and other outcomes in this last cohort. TBI based conditioning was associated with improved OS, LFS, and RI in both MRD negative and MRD positive patients (figure). In this large study we confirmed that patients who are MRD negative prior to HCT achieve superior outcomes. This is particularly apparent if TBI conditioning is used. All patients with ALL irrespective of MRD status benefit from TBI based conditioning in myeloablative setting. [ABSTRACT FROM AUTHOR]