Allogeneic hematopoietic cell transplantation is equally effective in secondary acute lymphoblastic leukemia (ALL) compared to de-novo ALL-a report from the EBMT registry.

Secondary acute lymphoblastic leukemia (s-ALL) comprises up to 10% of ALL patients. However, data regarding s-ALL outcomes is limited. To answer what is the role of allogeneic hematopoietic cell transplantation (HCT) in s-ALL, a matched-pair analysis in a 1:2 ratio was conducted to compare outcomes between s-ALL and de novo ALL (dn-ALL) patients reported between 2000-2021 to the European Society for Blood and Marrow Transplantation registry. Among 9720 ALL patients, 351 (3.6%) were s-ALL, of which 80 were in first complete remission (CR1) with a known precedent primary diagnosis 58.8% solid tumor (ST), 41.2% hematological diseases (HD). The estimated 2-year relapse incidence (RI) was 19.1% (95%CI: 11-28.9), leukemia-free survival (LFS) 52.1% (95%CI: 39.6-63.2), non-relapse mortality (NRM) 28.8% (95%CI: 18.4-40), GvHD-free, relapse-free survival (GRFS) 39.4% (95%CI: 27.8-50.7), and overall survival (OS) 60.8% (95%CI: 47.9-71.4), and did not differ between ST and HD patients. In a matched-pair analysis, there was no difference in RI, GRFS, NRM, LFS, or OS between s-ALL and dn-ALL except for a higher incidence of chronic GvHD (51.9% vs. 31.4%) in s-ALL. To conclude, patients with s-ALL who received HCT in CR1 have comparable outcomes to patients with dn-ALL.

Artificial intelligence methods to estimate overall mortality and non-relapse mortality following allogeneic HCT in the modern era: an EBMT-TCWP study.

Allogeneic haematopoietic cell transplantation (alloHCT) has curative potential counterbalanced by its toxicity. Prognostic scores fail to include current era patients and alternative donors. We examined adult patients from the EBMT registry who underwent alloHCT between 2010 and 2019 for oncohaematological disease. Our primary objective was to develop a new prognostic score for overall mortality (OM), with a secondary objective of predicting non-relapse mortality (NRM) using the OM score. AI techniques were employed. The model for OM was trained, optimized, and validated using 70%, 15%, and 15% of the data set, respectively. The top models, "gradient boosting" for OM (AUC = 0.64) and "elasticnet" for NRM (AUC = 0.62), were selected. The analysis included 33,927 patients. In the final prognostic model, patients with the lowest score had a 2-year OM and NRM of 18 and 13%, respectively, while those with the highest score had a 2-year OM and NRM of 82 and 93%, respectively. The results were consistent in the subset of the haploidentical cohort (n = 4386). Our score effectively stratifies the risk of OM and NRM in the current era but do not significantly improve mortality prediction. Future prognostic scores can benefit from identifying biological or dynamic markers post alloHCT.

Impact of patient: donor HLA disparity on reduced-intensity-conditioned allogeneic stem cell transplants from HLA mismatched unrelated donors for AML: from the ALWP of the EBMT.

Patients with acute myeloid leukaemia (AML) who lack a matched sibling or unrelated donor commonly undergo transplantation from a donor matched at 9/10 HLA-A, -B, -C, -DRB1, -DQB1 alleles, and it is unclear if a specific locus mismatch is preferable to any other. We therefore studied 937 patients with AML in complete remission transplanted using a reduced intensity conditioning regimen from an unrelated donor mismatched at a single allele. In a multivariate analysis, patient age, adverse karyotype and patient cytomegalovirus (CMV) seropositivity were correlated with decreased leukaemia free survival (LFS) and overall survival (OS). There was no significant difference in LFS or OS between patients transplanted from donors mismatched at HLA-A, -B, -C or -DRB1 in comparison to a HLA-DQB1 mismatched transplant. In a multivariate analysis, patients transplanted with a HLA-A mismatched donor had higher rates of acute graft-versus-host disease (GVHD) and non-relapse mortality (NRM) than patients transplanted with a HLA-DQB1 mismatched donor. Patient CMV seropositivity was associated with an increase in NRM and acute GVHD and reduced LFS and OS, regardless of donor CMV status. For CMV seropositive patients lacking a fully matched donor, alternative GVHD and CMV prophylaxis strategies should be considered.

Post-remission therapy of adults aged 60 and older with acute myeloid leukemia in first complete remission: role of treatment intensity on the outcome.

Although complete remission (CR) is achieved in 50 to 70% of older fit patients with acute myeloid leukemia (AML), consolidation therapy in this age group remains challenging. In this retrospective study, we aimed to compare outcome in elderly patients treated with different post-remission modalities, including allogenic and autologous hematopoietic stem cell transplantation (HSCT), intensive chemotherapy, and standard-dose chemotherapy (repeated 1 + 5 regimen). We collected data of 441 patients ≥ 60 years in first CR from a single institution. Median age was 67 years. Sixty-one (14%) patients received allo-HSCT, 51 (12%) auto-HSCT, 70 (16%) intensive chemotherapy with intermediate- or high-dose cytarabine (I/HDAC), and 190 (43%) 1 + 5 regimen. Median follow-up was 6.5 years. In multivariate analysis, allo-HSCT, cytogenetics, and PS had a significant impact on OS and LFS. In spite of a more favorable-risk profile, the patients who received I/HDAC had no significantly better LFS as compared with patients treated with 1 + 5 (median LFS 8.8 months vs 10.6 months, p = 0.96). In transplanted patients, median LFS was 13.3 months for auto-HSCT and 25.8 months for allo-HSCT. Pre-transplant chemotherapy with I/HDAC had no effect on the outcome. Toxicity was significantly increased for both transplanted and non-transplanted patients treated with I/HDAC, with more units of blood and platelet transfusion and more time spent in hospitalization, but no higher non-relapse mortality. This study shows that post-remission chemotherapy intensification is not associated with significantly better outcome as compared with standard-dose chemotherapy in elderly patients for whom, overall results remain disappointing.

Outcome in patients with diffuse large B-cell lymphoma who relapse after autologous stem cell transplantation and receive active therapy. A retrospective analysis of the Lymphoma Working Party of the European Society for Blood and Marrow Transplantation (EBMT).

Autologous hematopoietic stem cell transplantation (auto-HSCT) is the standard of care for patients with diffuse large B-cell lymphoma (DLBCL) who relapse/progress after first line chemoimmunotherapy. Long-term outcome of those who relapse after transplant is poor. We present the results of a retrospective study of 256 adult patients reported to the EBMT registry with DLBCL who relapsed after auto-HSCT performed between 2003 and 2013, and who received active salvage strategies. One hundred and fifty-four (60%) were male; median age was 53 years. Median time to relapse was 7 months, 65% relapsed during the first year. Overall response rate after salvage therapy was 46%. Median follow-up after first salvage therapy was 40 months (IQR 23-63 months). Overall survival (OS) at 3 years was 27% (95% CI 22-33). OS at 3 years of patients relapsing longer than 1 year after auto-HSCT was 41% (95% CI 31-53) compared with 20% (95% CI 14-24) in those who relapsed in less than 1 year. Eighty-two patients (32%) had a second HSCT, an allogeneic HSCT (allo-HSCT) in 69 cases, at a median time of 6.5 months after relapse. OS at 3 years after allo-HSCT was 36% (95% CI 25-51). In conclusion, the prognosis of patients with DLBCL that relapse after auto-HSCT is dismal. Patients who relapse in less than 1 year remain an unmet need, and should be considered for CAR T cell therapy or clinical trials. Patients who relapse after 1 year can be rescued with salvage therapies and a second HSCT. These results provide a benchmark to compare data of new prospective studies.

Postremission Consolidation by Autologous Hematopoietic Cell Transplantation (HCT) for Acute Myeloid Leukemia in First Complete Remission (CR) and Negative Implications for Subsequent Allogeneic HCT in Second CR: A Study by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT).

After autologous hematopoietic cell transplantation (HCT) in the first complete remission (CR1), patients with acute myeloid leukemia (AML) may relapse and undergo allogeneic HCT in the second complete remission (CR2). The aim of this study was to analyze the outcome of allogeneic HCT performed in CR2 comparing patients with prior consolidation by autologous HCT versus patients with chemotherapy consolidation. Included were 2619 adults with allogeneic HCT in CR2 from 2000 to 2017 with (n = 417) or without (n = 2202) prior autologous HCT. Patient groups were not entirely comparable; patients with prior autologous HCT were younger, had less often a favorable cytogenetic profile, had more commonly donors other than matched siblings, and more often received reduced-intensity conditioning. In multivariate analysis, nonrelapse mortality risks in patients with prior autologous HCT were 1.34 (1.07 to 1.67; P = .01) after adjustment for age, cytogenetic risk, transplant year, donor, conditioning intensity, sex matching, interval diagnosis-relapse, and relapse-allogeneic HCT as compared with chemotherapy consolidation. Similarly, risks of events in leukemia-free survival and graft-versus-host disease, relapse-free survival were higher with prior autologous HCT, 1.17 (1.01 to 1.35), P = .03 and 1.18 (1.03 to 1.35), P = .02, respectively. Risk of death was also higher, 1.13 (0.97 to 1.32), P = .1, but this was not significant. Postremission consolidation with autologous HCT for AML in CR1 increases toxicity of subsequent allogeneic HCT in CR2.

[CAR-T cells: Lymphocytes that express a chimeric antigen receptor]. / CAR-T cells : lymphocytes exprimant un récepteur chimérique à l'antigène.

CAR-T cells are genetically modified human lymphocytes and gene therapy medicinal products. They are developed to treat cancers that express a membrane antigen targeted by the CAR. The FDA approved the two first-in-class medicinal products in 2017 and EMA in August 2018; both are autologous CAR-T cells targeting CD19 that is expressed at the surface of normal B-cells throughout their differentiation, and on B-cell lymphoid malignancies. Clinical efficacy was demonstrated for B-cell acute lymphoblastic leukemias, non-Hodgkin's lymphoma and chronic lymphocytic leukemia, although the marketing authorizations are less liberal in terms of indications. Manufacturing of these personalized treatments necessitates that a novel organization and supply chain be set in place, to ensure product preservation, patient safety and compliance with complex regulatory requirements. Side effects are commensurate with clinical efficacy and can be life-threatening: proper management imposes tight coordination between various specialists, particularly between hematologists and intensive care practitioners. High pricing for these treatments is part of a long-term trend for increasing costs of innovations in hematology and oncology; it questions the ability of healthcare systems to sustain their reimbursement.

Cord blood transplantation is associated with good outcomes in secondary Acute Myeloid Leukaemia in first remission.

BACKGROUND: We conducted a retrospective survey within the European Society for Blood and Marrow Transplantation (EBMT) registry to assess the outcomes of cord blood transplantation (CBT) in secondary acute myeloid leukaemia (sAML). METHODS: Inclusion criteria consisted of ≥18 years of age, sAML, first CBT between 2002 and 2016, and either first complete remission (CR) or active disease at CBT. RESULTS: One hundred forty-six patients met the study inclusion criteria. Status at transplantation was first CR (n = 97), primary refractory sAML (n = 30) or relapsed (n = 19) sAML. Neutrophil engraftment was achieved in 118 patients while the remaining 25 patients (17%) failed to engraft. This includes 13% of patients transplanted in first CR versus 30% of those transplanted with active disease (P = 0.008). Two-year incidences of relapse were 25% in first CR patients versus 36% in those with advanced disease (P = 0.06) while 2-year incidences of nonrelapse mortality were 35% and 49% (P = 0.03), respectively. At 2-year overall survival, leukaemia-free survival and graft-versus-host disease (GVHD)-free relapse-free survival were 42% vs. 19% (P < 0.001), 40% vs. 16% (P < 0.001), and 26% vs. 12% (P = 0.002) in first CR patients versus those with advanced disease, respectively. CONCLUSIONS: We report here the first study of CBT in a large cohort of sAML patients. Main observation was that CBT rescued approximately 40% of patients with sAML in first CR.

Sarcopenic obesity derived from PET/CT predicts mortality in lymphoma patients undergoing hematopoietic stem cell transplantation.

BACKGROUND: Sarcopenic Obesity (SO) is associated with worse survival among chemotherapy recipients. Research on SO is scarce among lymphoma patients receiving Hematopoietic Stem Cell Transplantation (HSCT). AIM: assess prevalence of SO pre-HSCT (T0) and 3 months post-HSCT (T1) in lymphoma patients and determine the power of SO at T0 and T1 in predicting survival. METHODS: Consecutive patients (age ≥16 years) having B and T cell lymphoma who underwent SCT and who had PET/CT scan pre-SCT and 3 months post SCT were included in the study. A cross sectional image was analyzed at the level of the 3rd Lumber Vertebrae to assess body composition parameters. RESULTS: 93 patients [mean age: 38 (range: 17-70 years), 52 (55.9%) males, 45 (48%) Hodgkin and 48 (52%) Non-Hodgkin lymphoma, 81 (87%) autologous and 12 (13%) allogeneic SCT)] met the inclusion criteria. From T0 to T1, Sarcopenia rates increased (27% at T0 to 38% at T1, p = 0.013), Visceral adiposity decreased (46% at T0 to 30% at T1, p = 0.03) and SO decreased (42% at T0 to 20% at T1, p < 0.01). Length of stay, overall survival and progression free survival were significantly better in patients without sarcopenic obesity at T1. Cox-regression revealed SO at T1 was a risk factor for mortality [Adjusted Hazards Ratio = 8.2 (95% Confidence Interval: 1.9-36.2)]. CONCLUSION: Sarcopenic obesity, prevalent in 42% of patients pre-HSCT, decreased 3 months post HSCT as lymphoma patients lost skeletal muscle and visceral adipose tissues. SO at T1 was the most impactful risk factor for mortality.

Corrigendum: Disease status is a more reliable predictive factor than histology in lymphoma patients after reduced-intensity conditioning regimen and allo-SCT.

This corrects the article DOI: 10.1038/bmt.2012.225.

Impact of HLA-G polymorphism on the outcome of allogeneic hematopoietic stem cell transplantation for metastatic renal cell carcinoma.

Renal cell carcinoma (RCC) is particularly sensitive to immune intervention. HLA-G, a non-classical HLA class I molecule with immunomodulatory properties, has been studied with regard to outcome after hematopoietic stem cell transplantation (HSCT), in particular the 14 bp insertion/deletion polymorphism in the 3' untranslated region. Here we analyzed n=56 patients affected by metastatic RCC who received an allogeneic HSCT between 1998 and 2006 in Milano, Marseille, Clermont-Ferrand and Stockholm. The 14 bp polymorphism was analyzed in correlation with overall survival (OS), PFS, acute and chronic GvHD. With a median follow-up of 13 years, a trend towards better outcome was observed when homozygosity for the 14bp-del allele was present: multivariate hazard ratio was 0.50 (95% confidence interval (CI): 0.23-1.13; P=0.10) and 0.57 (95% CI: 0.26-1.26; P=0.17) for OS and PFS, respectively, when 14bp-del/del was compared with 14bp-ins/X. Further exploratory analysis revealed a significant association between T/C at p3003 and improved OS (P=0.05) and PFS (P=0.006) compared with T/T. To our knowledge this is the first study on HLA-G and outcome after HSCT for a solid malignancy. After a coordinated multicenter study, we found that the more tolerogenic polymorphisms (14bp-del/del) is associated with better PFS and OS. The finding on p3003 deserves further investigation.

Distinct factors determine the kinetics of disease relapse in adults transplanted for acute myeloid leukaemia.

BACKGROUND: Disease recurrence remains the major cause of death in adults with acute myeloid leukaemia (AML) treated using either intensive chemotherapy (IC) or allogenic stem cell transplantation (allo-SCT). AIMS: The timely delivery of maintenance drug or cellular therapies represent emerging strategies with the potential to reduce relapse after both treatment modalities, but whilst the determinants of overall relapse risk have been extensively characterized the factors determining the timing of disease recurrence have not been characterized. MATERIALS AND METHODS: We have therefore examined, using a series of sequential landmark analyses, relapse kinetics in a cohort of 2028 patients who received an allo-SCT for AML in CR1 and separately 570 patients treated with IC alone. RESULTS: In the first 3 months after allo-SCT, the factors associated with an increased risk of relapse included the presence of the FLT3-ITD (P < 0.001), patient age (P = 0.012), time interval from CR1 to transplant (P < 0.001) and donor type (P = 0.03). Relapse from 3 to 6 months was associated with a higher white cell count at diagnosis (P = 0.001), adverse-risk cytogenetics (P < 0.001), presence of FLT3-ITD mutation (P < 0.001) and time interval to achieve first complete remission (P = 0.013). Later relapse was associated with adverse cytogenetics, mutated NPM1, absence of chronic graft-versus-host disease (GVHD) and the use of in vivo T-cell depletion. In patients treated with IC alone, the factors associated with relapse in the first 3 months were adverse-risk cytogenetics (P < 0.001) and FLT3-ITD status (P = 0.001). The factors predicting later relapse were the time interval from diagnosis to CR1 (P = 0.22) and time interval from CR1 to IC (P = 0.012). DISCUSSION AND CONCLUSION: Taken together, these data provide novel insights into the biology of disease recurrence after both allo-SCT and IC and have the potential to inform the design of novel maintenance strategies in both clinical settings.

Reduced-intensity versus reduced-toxicity myeloablative fludarabine/busulfan-based conditioning regimens for allografted non-Hodgkin lymphoma adult patients: a retrospective study on behalf of the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire.

BACKGROUND: Fludarabine/busulfan-based conditioning regimens are widely used to perform allogeneic stem-cell transplantation (allo-SCT) in high-risk non-Hodgkin lymphoma (NHL) patients. The impact of the dose intensity of busulfan on outcomes has not been reported yet. PATIENTS AND METHODS: This was a retrospective with the aim to compare the outcomes of NHL patients who received before allo-SCT a fludarabine/busulfan conditioning regimen, either of reduced intensity (FB2, 2 days of busulfan at 4 mg/kg/day oral or 3.2 mg/kg/day i.v.) (n = 277) or at a myeloablative reduced-toxicity dose (FB3/FB4, 3 or 4 days of busulfan at 4 mg/kg/day oral or 3.2 mg/kg/day i.v.) (n = 101). RESULTS: In univariate analysis, the 2-year overall survival (FB2 66.5% versus 60.3%, P = 0.33), lymphoma-free survival (FB2 57.9% versus 49.8%, P = 0.26), and non-relapse mortality (FB2 19% versus 21.1%, P = 0.91) were similar between both groups. Cumulative incidence of grade III-IV acute graft versus host disease (GVHD) (FB2 11.2% versus 18%, P = 0.08), extensive chronic GVHD (FB2: 17.3% versus 10.7%, P = 0.18) and 2-year GVHD free-relapse free survival (FB2: 44.4% versus 42.8%, P = 0.38) were also comparable. In multivariate analysis there was a trend for a worse outcome using FB3/FB4 regimens (overall survival: HR 1.47, 95% CI: 0.96-2.24, P = 0.08; lymphoma-free survival: HR: 1.43, 95% CI: 0.99-2.06, P = 0.05; relapse incidence: HR 1.54; 95% CI: 0.96-2.48, P = 0.07). These results were confirmed using a propensity score-matching strategy. CONCLUSION: We conclude that reduced toxicity myeloablative conditioning with fludarabine/busulfan does not improve the outcomes compared with reduced-intensity conditioning in adults receiving allo-SCT for NHL.

Allogeneic haematopoietic stem cell transplant in patients with lower risk myelodysplastic syndrome: a retrospective analysis on behalf of the Chronic Malignancy Working Party of the EBMT.

This corrects the article DOI: 10.1038/bmt.2016.266.

Haploidentical transplantation with post-infusion cyclophosphamide in advanced Hodgkin lymphoma.

We investigated the use of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in the treatment of advanced Hodgkin lymphoma (HL). Sixty-two consecutive HL patients underwent haplo-HSCT. Unmanipulated stem cells and post-transplant cyclophosphamide were given to all patients as GVHD prophylaxis. At 100 days, the cumulative incidence of grades 2-3 and grades 3-4 acute GVHD was 23% and 4%, respectively. The chronic GVHD (cGVHD) cumulative incidence was 16%, with one patient experiencing severe cGVHD. The 3-year OS, PFS, relapse rates and 1-year non-relapse mortality (NRM) were 63%, 59%, 21% and 20%, respectively. Uncontrolled disease status and high hematopoietic cell transplantation comorbidity index (HCT-CI) were associated with lower OS, whereas PBSC was an independent protective factor. Uncontrolled disease and HCT-CI >2 was predictive for NRM. Finally, disease status other than CR was predictive of relapse. In conclusion, haplo-HSCT is a valid treatment in advanced HL, offering excellent rates of survival and acceptable toxicities.

Risk of sinusoidal obstruction syndrome in allogeneic stem cell transplantation after prior gemtuzumab ozogamicin treatment: a retrospective study from the Acute Leukemia Working Party of the EBMT.

Gemtuzumab ozogamicin (GO) may increase the risk of sinusoidal obstruction syndrome (SOS) when used prior to allogeneic stem cell transplantation (HSCT). We assessed SOS incidence and outcomes after HSCT of 146 adults, with a median age of 50 years, previously receiving GO. SOS prophylaxis was used in 69 patients (heparin n=57, ursodeoxycholic acid n=8, defibrotide n=4). Cumulative incidence (CI) of SOS was 8% (n=11), with death in 3 patients. Median interval between last GO dose and HSCT was 130 days. Overall survival (OS) and SOS incidence did not differ for patients receiving GO ⩽3.5 months before HSCT and the others. CI of acute and chronic GVHD was 31% and 25%, respectively. Probability of OS and leukemia-free survival (LFS) at 5 years was 40% and 37%, respectively. Relapse incidence and non-relapse mortality were 42% and 21%, respectively. In multivariate analysis, active disease at HSCT was associated with relapse and worse LFS and OS (P<0.03). Liver abnormalities before HSCT correlated with worse OS (P<0.03). Use of low-dose GO prior to HSCT is associated with an acceptable SOS incidence. Prospective studies investigating the role and the utility of SOS prophylaxis are warranted.

Reduced-intensity and non-myeloablative allogeneic stem cell transplantation from alternative HLA-mismatched donors for Hodgkin lymphoma: a study by the French Society of Bone Marrow Transplantation and Cellular Therapy.

Allogeneic stem cell transplantation (allo-SCT) following a non-myeloablative (NMA) or reduced-intensity conditioning (RIC) is considered a valid approach to treat patients with refractory/relapsed Hodgkin lymphoma (HL). When an HLA-matched donor is lacking a graft from a familial haploidentical (HAPLO) donor, a mismatched unrelated donor (MMUD) or cord blood (CB) might be considered. In this retrospective study, we compared the outcome of patients with HL undergoing a RIC or NMA allo-SCT from HAPLO, MMUD or CB. Ninety-eight patients were included. Median follow-up was 31 months for the whole cohort. All patients in the HAPLO group (N=34) received a T-cell replete allo-SCT after a NMA (FLU-CY-TBI, N=31, 91%) or a RIC (N=3, 9%) followed by post-transplant cyclophosphamide. After adjustment for significant covariates, MMUD and CB were associated with significantly lower GvHD-free relapse-free survival (GRFS; hazard ratio (HR)=2.02, P=0.03 and HR=2.43, P=0.009, respectively) compared with HAPLO donors. In conclusion, higher GRFS was observed in Hodgkin lymphoma patients receiving a RIC or NMA allo-SCT with post-transplant cyclophosphamide from HAPLO donors. Our findings suggest they should be favoured over MMUD and CB in this setting.

Long-term survival of patients with CLL after allogeneic transplantation: a report from the European Society for Blood and Marrow Transplantation.

Even with the availability of targeted drugs, allogeneic hematopoietic cell transplantation (allo-HCT) is the only therapy with curative potential for patients with CLL. Cure can be assessed by comparing long-term survival of patients to the matched general population. Using data from 2589 patients who received allo-HCT between 2000 and 2010, we used landmark analyses and methods from relative survival analysis to calculate excess mortality compared with an age-, sex- and calendar year-matched general population. Estimated event-free survival, overall survival and non-relapse mortality (NRM) 10 years after allo-HCT were 28% (95% confidence interval (CI), 25-31), 35% (95% CI, 32-38) and 40% (95% CI, 37-42), respectively. Patients who passed the 5-year landmark event-free survival (N=394) had a 79% probability (95% CI, 73-85) of surviving the subsequent 5 years without an event. Relapse and NRM contributed equally to treatment failure. Five-year mortality for 45- and 65-year-old reference patients who were event-free at the 5-year landmark was 8% and 47% compared with 3% and 14% in the matched general population, respectively. The prospect of long-term disease-free survival remains an argument to consider allo-HCT for young patients with high-risk CLL, and programs to understand and prevent late causes of failure for long-term survivors are warranted, especially for older patients.