Measurable residual disease status and outcome of transplant in acute myeloid leukemia in second complete remission: a study by the acute leukemia working party of the EBMT.

Measurable residual disease (MRD) prior to hematopoietic cell transplant (HCT) for acute myeloid leukemia (AML) in first complete morphological remission (CR1) is an independent predictor of outcome, but few studies address CR2. This analysis by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation registry assessed HCT outcomes by declared MRD status in a cohort of 1042 adult patients with AML CR2 at HCT. Patients were transplanted 2006-2016 from human leukocyte antigen (HLA) matched siblings (n = 719) or HLA 10/10 matched unrelated donors (n = 293). Conditioning was myeloablative (n = 610) or reduced-intensity (n = 432) and 566 patients (54%) had in-vivo T cell depletion. At HCT, 749 patients (72%) were MRD negative (MRD NEG) and 293 (28%) were MRD positive (MRD POS). Time from diagnosis to HCT was longer in MRD NEG than MRD POS patients (18 vs. 16 months (P < 0.001). Two-year relapse rates were 24% (95% CI, 21-28) and 40% (95% CI, 34-46) in MRD NEG and MRD POS groups (P < 0.001), respectively. Leukemia-free survival (LFS) was 57% (53-61) and 46% (40-52%), respectively (P = 0.001), but there was no difference in terms of overall survival. Prognostic factors for relapse and LFS were MRD NEG status, good risk cytogenetics, and longer time from diagnosis to HCT. In-vivo T cell depletion predicted relapse.

Development and validation of a disease risk stratification system for patients with haematological malignancies: a retrospective cohort study of the European Society for Blood and Marrow Transplantation registry.

BACKGROUND: Diagnosis and remission status at the time of allogeneic haematopoietic stem-cell transplantation (HSCT) are the principal determinants of overall survival following transplantation. We sought to develop a contemporary disease-risk stratification system (DRSS) that accounts for heterogeneous transplantation indications. METHODS: In this retrospective cohort study we included 55 histology and remission status combinations across haematological malignancies, including acute leukaemia, lymphoma, multiple myeloma, and myeloproliferative and myelodysplastic disorders. A total of 47 265 adult patients (aged ≥18 years) who received an allogeneic HSCT between Jan 1, 2012, and Dec 31, 2016, and were reported to the European Society for Blood and Marrow Transplantation registry were included. We divided EBMT patients into derivation (n=25 534), tuning (n=18 365), and geographical validation (n=3366) cohorts. Disease combinations were ranked in a multivariable Cox regression for overall survival in the derivation cohort, cutoff for risk groups were evaluated for the tuning cohort, and the selected system was tested on the geographical validation cohort. An independent single-centre US cohort of 660 patients transplanted between Jan 1, 2010, and Dec 31, 2015 was used to externally validate the results. FINDINGS: The DRSS model stratified patients in the derivation cohort (median follow-up was 2·1 years [IQR 1·0-3·2]) into five risk groups with increasing mortality risk: low risk (reference group), intermediate-1 (hazard ratio for overall survival 1·26 [95% CI 1·17-1·36], p<0·0001), intermediate-2 (1·53 [1·42-1·66], p<0·0001), high (2·03 [1·86-2·22], p<0·0001), and very high (2·87 [2·63-3·13], p<0·0001). DRSS levels were also associated with a stepwise increase in risk across the tuning and geographical validation cohort. In the external validation cohort (median follow-up was 5·7 years [IQR 4·5-7·1]), the DRSS scheme separated patients into 4 risk groups associated with increasing risk of mortality: intermediate-2 risk (hazard ratio [HR] 1·34 [95% CI 1·04-1·74], p=0·025), high risk (HR 2·03 [95% CI 1·39-2·95], p=0·00023) and very-high risk (HR 2·26 [95% CI 1·62-3·15], p<0·0001) patients compared with the low risk and intermediate-1 risk group (reference group). Across all cohorts, between 64% and 65% of patients were categorised as having intermediate-risk disease by a previous prognostic system (ie, the disease-risk index [DRI]). The DRSS reclassified these intermediate-risk DRI patients, with 855 (6%) low risk, 7111 (51%) intermediate-1 risk, 5700 (41%) intermediate-2 risk, and 375 (3%) high risk or very high risk of 14 041 patients in a subanalysis combining the tuning and internal geographic validation cohorts. The DRI projected 2-year overall survival was 62·1% (95% CI 61·2-62·9) for these 14 041 patients, while the DRSS reclassified them into finer prognostic groups with overall survival ranging from 45·7% (37·4-54·0; very high risk patients) to 73·1% (70·1-76·2; low risk patients). INTERPRETATION: The DRSS is a novel risk stratification tool including disease features related to histology, genetic profile, and treatment response. The model should serve as a benchmark for future studies. This system facilitates the interpretation and analysis of studies with heterogeneous cohorts, promoting trial-design with more inclusive populations. FUNDING: The Varda and Boaz Dotan Research Center for Hemato-Oncology Research, Tel Aviv University.

Measurable residual disease (MRD) testing for acute leukemia in EBMT transplant centers: a survey on behalf of the ALWP of the EBMT.

Detectable measurable residual disease (MRD) is a key prognostic factor in both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) patients. Thus, we conducted a survey in EBMT transplant centers focusing on pre- and post-allo-HCT MRD. One hundred and six centers from 29 countries responded. One hundred had a formal strategy for routine MRD assessment, 91 for both ALL and AML. For ALL (n = 95), assessing MRD has been routine practice starting from 2010 (range, 1990-2019). Techniques used for MRD assessment consisted of PCR techniques alone (n = 27), multiparameter flow cytometry (MFC, n = 16), both techniques (n = 43), next-generation sequencing (NGS) + PCR (n = 2), or PCR + MFC + NGS (n = 7). The majority of centers assessed MRD every 2-3 months for 2 (range, 1-until relapse) years. For AML, assessing MRD was routine in 92 centers starting in 2010 (range 1990-2019). Assessment of MRD was by PCR (n = 23), MFC (n = 13), both PCR and MFC (n = 39), both PCR and NGS (n = 3), and by all three techniques (n = 14). The majority assesses MRD for AML every 2-3 months for 2 (range, 1-until relapse) years. This survey is the first step in the aim to include MRD status as a routine registry capture parameter in acute leukemia.

Production, safety and efficacy of iPSC-derived mesenchymal stromal cells in acute steroid-resistant graft versus host disease: a phase I, multicenter, open-label, dose-escalation study.

The therapeutic potential of donor-derived mesenchymal stromal cells (MSCs) has been investigated in diverse diseases1, including steroid-resistant acute graft versus host disease (SR-aGvHD)2. However, conventional manufacturing approaches are hampered by challenges with scalability and interdonor variability, and clinical trials have shown inconsistent outcomes3,4. Induced pluripotent stem cells (iPSCs) have the potential to overcome these challenges, due to their capacity for multilineage differentiation and indefinite proliferation5,6. Nonetheless, human clinical trials of iPSC-derived cells have not previously been completed. CYP-001 (iPSC-derived MSCs) is produced using an optimized, good manufacturing practice (GMP)-compliant manufacturing process. We conducted a phase 1, open-label clinical trial (no. NCT02923375) in subjects with SR-aGvHD. Sixteen subjects were screened and sequentially assigned to cohort A or cohort B (n = 8 per group). One subject in cohort B withdrew before receiving CYP-001 and was excluded from analysis. All other subjects received intravenous infusions of CYP-001 on days 0 and 7, at a dose level of either 1 × 106 cells per kg body weight, to a maximum of 1 × 108 cells per infusion (cohort A), or 2 × 106 cells per kg body weight, to a maximum dose of 2 × 108 cells per infusion (cohort B). The primary objective was to assess the safety and tolerability of CYP-001, while the secondary objectives were to evaluate efficacy based on the proportion of participants who showed a complete response (CR), overall response (OR) and overall survival (OS) by days 28/100. CYP-001 was safe and well tolerated. No serious adverse events were assessed as related to CYP-001. OR, CR and OS rates by day 100 were 86.7, 53.3 and 86.7%, respectively. The therapeutic application of iPSC-derived MSCs may now be explored in diverse inflammatory and immune-mediated diseases.

Allogeneic haemopoietic transplantation for acute myeloid leukaemia in second complete remission: a registry report by the Acute Leukaemia Working Party of the EBMT.

Allogeneic haemopoietic cell transplant (allo-HCT) may be curative in acute myeloid leukaemia (AML) in second complete remission (CR2) but the impact of reduced intensity (RIC) versus myeloablative conditioning (MAC) is uncertain. The Acute Leukaemia Working Party of the European Society for Blood and Bone Marrow Transplantation Registry studied an AML CR2 cohort characterised by age ≥ 18 years, first allo-HCT 2007-2016, available cytogenetic profile at diagnosis, donors who were matched family, volunteer unrelated with HLA antigen match 10/10 or 9/10 or haplo-identical. The 1879 eligible patients included 1010 (54%) MAC allo-HCT recipients. In patients <50 years (y), two year outcomes for MAC vs RIC allo-HCT were equivalent with leukaemia-free survival (LFS) 54% for each, overall survival (OS), 61% vs 62%, non-relapse mortality (NRM) 18% vs 15% and graft versus host disease relapse-free survival (GRFS) 38% vs 42%. In patients ≥50 y, 2 y outcomes for MAC vs RIC allo-HCT were equivalent for LFS 52% vs 49%, OS 58% vs 55% and GRFS 42.4% vs 36%. However, NRM was significantly inferior after MAC allo-HCT, 27% vs 19% (P = 0.01) despite worse cGVHD after RIC-allo (32% vs 39%). These data support the need for ongoing prospective study of conditioning intensity and GVHD mitigation in AML.

Conditioning intensity in secondary AML with prior myelodysplastic syndrome/myeloproliferative disorders: an EBMT ALWP study.

Patients with secondary AML (sAML) with antecedent myelodysplastic syndrome (MDS) or myeloproliferative neoplasms (MPNs) tend to have high-risk disease based on the older age of patients, high-risk cytogenetics, and higher number of prior treatments. Allogeneic hematopoietic cell transplant (HCT) is the only potentially curative therapy available. Eight hundred and two adults with sAML and prior MDS/MPN who received a first HCT between 2000 and 2016 were included in the European Society for Blood and Marrow Transplant (EBMT) Acute Leukemia Working Party (ALWP) study. Median age of the cohort was 59.6 years (range, 18.6-78.6 years). Myeloablative conditioning (MAC) was given to 40% of patients, and 60% received reduced-intensity conditioning (RIC). Overall, the 2-year cumulative incidence of relapse (RI) was 37%, leukemia-free survival (LFS) was 40%, overall survival (OS) was 46%, nonrelapse mortality (NRM) was 23%, and chronic graft-versus-host disease (cGVHD) was 39%. In univariate analysis, a statistical difference between conditioning regimens 6 months after HCT in favor of the MAC group was noted with regard to RI (hazard ratio [HR], 1.47; P = .03), LFS (HR, 1.43; P = .01), and OS (HR, 1.55; P < .05). There was no difference in the cumulative incidence of NRM (HR, 1.38; P = .15). This effect was similarly seen in multivariate analysis (MVA): cumulative incidence of relapse (HR, 1.79; P < .05), LFS (HR, 1.43; P = .02), and OS (HR, 1.53; P = .005) with no difference in NRM (HR, 1; P = .98). This EBMT ALWP analysis suggests that long-term survival can be achieved in patients with sAML with antecedent MDS/MPN and that MAC is a suitable conditioning regimen in patients with sAML.

Measurable residual disease, conditioning regimen intensity, and age predict outcome of allogeneic hematopoietic cell transplantation for acute myeloid leukemia in first remission: A registry analysis of 2292 patients by the Acute Leukemia Working Party European Society of Blood and Marrow Transplantation.

Patients with acute myeloid leukemia (AML) in morphological first complete remission (CR1) pre-allogeneic hematopoietic cell transplantation (HCT) may have measurable residual disease (MRD) by molecular and immunophenotyping criteria. We assessed interactions of MRD status with HCT conditioning regimen intensity in patients aged <50 years (y) or ≥50y. This was a retrospective study by the European Society for Blood and Marrow Transplantation registry. Patients were >18y with AML CR1 MRD NEG/POS and recipients of HCT in 2000-2015. Conditioning regimens were myeloablative (MAC), reduced intensity (RIC) or non-myeloablative (NMA). Outcomes included leukemia free survival (LFS), overall survival (OS), relapse incidence (RI), non-relapse mortality (NRM), chronic graft-vs-host (cGVHD), and GVHD-free and relapse-free survival (GRFS). The 2292 eligible patients were categorized into four paired groups: <50y MRD POS MAC (N = 240) vs RIC/NMA (N = 58); <50y MRD NEG MAC (N = 665) vs RIC/NMA (N = 195); ≥50y MRD POS MAC (N = 126) vs RIC/NMA (N = 230), and ≥50y MRD NEG MAC (N = 223) vs RIC/NMA (N = 555). In multivariate analysis RIC/NMA was only inferior to MAC for patients in the <50y MRD POS group, with worse RI (HR 1.71) and LFS (HR 1.554). Patients <50Y MRD NEG had less cGVHD after RIC/NMA HCT (HR 0.714). GRFS was not significantly affected by conditioning intensity in any group. Patients aged <50y with AML CR1 MRD POS status should preferentially be offered MAC allo-HCT. Prospective studies are needed to address whether patients with AML CR1 MRD NEG may be spared the toxicity of MAC regimens. New approaches are needed for ≥50y AML CR1 MRD POS.

The outcome of haemopoietic stem cell transplantation in the treatment of lymphoplasmacytic lymphoma in the UK: a British Society Bone Marrow Transplantation study.

Lymphoplasmacytic lymphoma (LL) is incurable by standard therapy (median survival: 60 months). UK transplant registry data 1984-2003 identified 18 cases of histologically verified LL (median age: 50 years, range: 38-58 years). Nine patients received high dose chemotherapy [plus total body irradiation (TBI) in 1/9] and autologous peripheral blood stem cells (PBSC). Disease status at transplant was complete remission (2), partial remission (5), primary refractory (1) or relapse (1). Transplant related mortality (TRM) at 12 months was 0%. Median follow-up is 44 months with 4 year disease free survival 43% and overall survival 73%. Karnofsky performance status (KPS) is 80-100%. The nine allografted patients (median age: 49 years, range: 39-56 years) were conditioned with standard TBI (2), BEAM (2) or FLU-MEL (5) and received PBSC from HLA-matched sibling (8) or unrelated (1) donors. Disease status at transplant was partial remission (7) or primary refractory (2). TRM at 12 months was 44%. Complications included graft failure (2), grades I-II acute graft versus host disease (aGVHD) (2), grades III-IV aGVHD (3) and chronic GVHD (4). Median follow-up is 32 months with 4 year disease free survival 44% and overall survival 56%. KPS is 70-100%.

Donor lymphocyte infusions for patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukaemia.

The understanding of the use of donor lymphocyte infusions (DLI) for graft-versus-leukaemia (GVL) in the treatment of chronic myeloid leukaemia (CML) post haemopoietic stem cell transplant (HSCT) has advanced during the last years. In relapsed leukaemia post-stem cell transplant, DLI can achieve durable remissions in 60-73% patients. Technical improvements in molecular methods of detection of the BCR-ABL transcripts permit the prediction of relapse with increased sensitivity and reproducibility. Use of DLI early at relapse is important since responses to DLI are less likely in the face of bulky or blast-phase disease. Exogenous interleukin-2 may enhance the response to DLI but total cell dose is also relevant to the efficacy of DLI with the effective cell dose (ECD) required being lower in HLA matched unrelated DLI donors compared to siblings. Donor T-lymphocytes target minor histocompatibility (H) antigens and the relative tissue distribution of these may influence the toxicity of DLI, which includes graft-versus-host-disease (GVHD). Modified methods of delivery such as selective deletion of CD8+ cells or escalating cell dosage regimens have reduced the incidence of serious morbidity due to GVHD without compromising the GVL effect mediated by DLI. These approaches have not removed the risk of GVHD entirely and conditional suicide protocols utilising the HSV-tk or fas receptor derived genes are being developed in the clinic. Since significant morbidity and mortality is attributable to the conditioning regimen used prior to HSCT, awareness of the potency of DLI has driven the development of reduced intensity conditioning (RIC) regimens. The purpose of RIC is to enhance tolerisation of the host to the graft while permitting the establishment of donor haemopoiesis. DLI may then be used subsequently to enhance the GVL effect.