Phase II trial of hypomethylating agent combined with nivolumab for acute myeloid leukaemia relapse after allogeneic haematopoietic cell transplantation-Immune signature correlates with response.

Acute myeloid leukaemia (AML) relapse after allogeneic haematopoietic cell transplantation (allo-HCT) is often driven by immune-related mechanisms and associated with poor prognosis. Immune checkpoint inhibitors combined with hypomethylating agents (HMA) may restore or enhance the graft-versus-leukaemia effect. Still, data about using this combination regimen after allo-HCT are limited. We conducted a prospective, phase II, open-label, single-arm study in which we treated patients with haematological AML relapse after allo-HCT with HMA plus the anti-PD-1 antibody nivolumab. The response was correlated with DNA-, RNA- and protein-based single-cell technology assessments to identify biomarkers associated with therapeutic efficacy. Sixteen patients received a median number of 2 (range 1-7) nivolumab applications. The overall response rate (CR/PR) at day 42 was 25%, and another 25% of the patients achieved stable disease. The median overall survival was 15.6 months. High-parametric cytometry documented a higher frequency of activated (ICOS+ , HLA-DR+ ), low senescence (KLRG1- , CD57- ) CD8+ effector T cells in responders. We confirmed these findings in a preclinical model. Single-cell transcriptomics revealed a pro-inflammatory rewiring of the expression profile of T and myeloid cells in responders. In summary, the study indicates that the post-allo-HCT HMA/nivolumab combination induces anti-AML immune responses in selected patients and could be considered as a bridging approach to a second allo-HCT. Trial-registration: EudraCT-No. 2017-002194-18.

Automated production of specific T cells for treatment of refractory viral infections after allogeneic stem cell transplantation.

Therapy-resistant viral reactivations contribute significantly to mortality after hematopoietic stem cell transplantation. Adoptive cellular therapy with virus-specific T cells (VST) has shown efficacy in various single-center trials. However, the scalability of this therapy is hampered by laborious production methods. In this study we describe the in-house production of VST in a closed system (CliniMACS Prodigy® system, Miltenyi Biotec). In addition, we report the efficacy in 26 patients with viral disease following hematopoietic stem cell transplantation in a retrospective analysis (adenovirus, n=7; cytomegalovirus, n=8; Epstein-Barr virus, n=4; multi-viral, n=7). The production of VST was successful in 100% of cases. The safety profile of VST therapy was favorable (n=2 grade 3 and n=1 grade 4 adverse events; all three were reversible). A response was seen in 20 of 26 patients (77%). Responding patients had a significantly better overall survival than patients who did not respond (P<0.001). Virus-specific symptoms were reduced or resolved in 47% of patients. The overall survival of the whole cohort was 28% after 6 months. This study shows the feasibility of automated VST production and safety of application. The scalability of the CliniMACS Prodigy® device increases the accessibility of VST treatment.

Prophylactic donor lymphocyte infusion after allogeneic stem cell transplantation in acute leukaemia - a matched pair analysis by the Acute Leukaemia Working Party of EBMT.

Strategies for relapse prevention after allogeneic transplantation in acute leukaemia are warranted. A registry-based matched-pair analysis evaluated the efficacy of prophylactic donor lymphocyte infusion (proDLI). Adults receiving proDLI in complete remission (CR) and controls were pair-matched for age, diagnosis, cytogenetics, stage, donor, gender, conditioning and T-cell depletion. Eighty-nine pairs were identified (median follow-up: 6.9 years). Within the entire cohort, no difference was observed. However, among patients with high-risk acute myeloid leukaemia (AML) (unfavourable cytogenetics and/or transplanted beyond first CR), proDLI recipients had improved overall survival (69.8% vs. 40.2% in controls, P = 0.027). ProDLI has moderate efficacy, but can contribute to improved outcome in high-risk AML.

Age-adjusted high-dose chemotherapy and autologous stem cell transplant in elderly and fit primary CNS lymphoma patients.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a diffuse large B-cell lymphoma (DLBCL) confined to the central nervous system (CNS) with rising incidence among patients > 65 years. Although elderly patients are able to tolerate aggressive systemic chemotherapy, previous studies have demonstrated inferior outcomes for patients who present with a poor performance status (PS) and older age. Usually, intensive treatment approaches including high-dose chemotherapy followed by autologous stem cell transplantation (HDT-ASCT) are only offered to patients younger than 65-70 years of age. METHODS: This is an open-label, multicentric, non-randomized, single arm phase II trial. We will recruit 51 immuno-competent patients with newly diagnosed PCNSL from 12 German centers. The objective is to investigate the efficacy of age-adapted induction treatment followed by HDT-ASCT. All enrolled patients will undergo induction chemotherapy consisting of 2 cycles of rituximab 375 mg/m2/d (days 0 & 4), methotrexate 3.5 g/m2 (d1), and cytarabine 2 × 2 g/m2/d (d2-3) every 21 days. After 2 cycles of induction chemotherapy, patients achieving at least stable disease will undergo HDT-ASCT with busulfan 3.2 mg/kg/d (days - 7-(- 6)) and thiotepa 5 mg/kg/d (days - 5-(- 4)) followed by autologous stem cell transplantation. The primary endpoint of this study is 1-year progression-free survival (PFS). Secondary endpoints include PFS, overall survival, treatment response and treatment-related morbidities. Minimal follow-up after treatment completion is 12 months. DISCUSSION: Current treatment options for PCNSL have improved over the last years, resulting in the potential to achieve durable remission or cure in patients < 70 years. Age alone may not be the only criterion to select patients for this effective treatment approach and probably many elderly patients are undertreated just because of advanced age. There have been no multicentre trials investigating this curative treatment concept in elderly and fit PCNSL patients so far. We aim to answer whether HDT-ASCT is feasible and effective in fit patients > 65 years with newly-diagnosed PCNSL. TRIAL REGISTRATION: German clinical trials registry DRKS00011932 registered 18 August 2017.

A wild bootstrap approach for the Aalen-Johansen estimator.

We suggest a wild bootstrap resampling technique for nonparametric inference on transition probabilities in a general time-inhomogeneous Markov multistate model. We first approximate the limiting distribution of the Nelson-Aalen estimator by repeatedly generating standard normal wild bootstrap variates, while the data is kept fixed. Next, a transformation using a functional delta method argument is applied. The approach is conceptually easier than direct resampling for the transition probabilities. It is used to investigate a non-standard time-to-event outcome, currently being alive without immunosuppressive treatment, with data from a recent study of prophylactic treatment in allogeneic transplanted leukemia patients. Due to non-monotonic outcome probabilities in time, neither standard survival nor competing risks techniques apply, which highlights the need for the present methodology. Finite sample performance of time-simultaneous confidence bands for the outcome probabilities is assessed in an extensive simulation study motivated by the clinical trial data. Example code is provided in the web-based Supplementary Materials.

Thiotepa-based conditioning versus total body irradiation as myeloablative conditioning prior to allogeneic stem cell transplantation for acute lymphoblastic leukemia: A matched-pair analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

The optimal conditioning regimen to employ before hematopoietic stem cell transplantation in acute lymphoblastic leukemia (ALL) is still undecided, and while cyclophosphamide/total body irradiation (Cy/TBI) is the most commonly used myeloablative regimen, there are concerns regarding long-term toxicity for patients conditioned with this regimen. Thiotepa-based conditioning is an emerging radiation-free regimen with recent publications indicative of comparable clinical outcomes to TBI-based conditioning. In this analysis of the acute leukemia working party of the EBMT, we performed a retrospective matched-pair analysis, evaluating the outcome of adult patients with ALL who received thiotepa-based conditioning (n = 180) with those receiving Cy/TBI conditioning (n = 540). The 2-year leukemia-free survival and overall survival (OS) rates of both conditioning regimens were comparable, 33% for thiotepa [95% confidence interval (CI): 26.4-42.8] versus 39% for Cy/TBI (95% CI: 34.8-44.5] (P = .33) and 46.5% [95% CI: 38.6-56.1] versus 48.8% [95% CI: 44.2-54] (P = .9), respectively. There was no significant difference between the two regimens in the incidence of either acute graft versus host disease (GVHD) or chronic GVHD. Multivariate analysis demonstrated increased relapse incidence for thiotepa conditioning compared to Cy/TBI (HR = 1.78, 95% CI, 1.07-2.95; P = .03) which did not affect OS. Our results indicate that thiotepa-based conditioning may not be inferior to Cy/TBI for adult patients with ALL.

Clinical activity of azacitidine in patients who relapse after allogeneic stem cell transplantation for acute myeloid leukemia.

Disease relapse is the most common cause of treatment failure after allogeneic stem cell transplantation for acute myeloid leukemia and myelodysplastic syndromes, yet treatment options for such patients remain extremely limited. Azacitidine is an important new therapy in high-risk myelodysplastic syndromes and acute myeloid leukemia but its role in patients who relapse post allograft has not been defined. We studied the tolerability and activity of azacitidine in 181 patients who relapsed after an allograft for acute myeloid leukemia (n=116) or myelodysplastic syndromes (n=65). Sixty-nine patients received additional donor lymphocyte infusions. Forty-six of 157 (25%) assessable patients responded to azacitidine therapy: 24 (15%) achieved a complete remission and 22 a partial remission. Response rates were higher in patients transplanted in complete remission (P=0.04) and those transplanted for myelodysplastic syndromes (P=0.023). In patients who achieved a complete remission, the 2-year overall survival was 48% versus 12% for the whole population. Overall survival was determined by time to relapse post transplant more than six months (P=0.001) and percentage of blasts in the bone marrow at time of relapse (P=0.01). The concurrent administration of donor lymphocyte infusion did not improve either response rates or overall survival in patients treated with azacitidine. An azacitidine relapse prognostic score was developed which predicted 2-year overall survival ranging from 3%-37% (P=0.00001). We conclude that azacitidine represents an important new therapy in selected patients with acute myeloid leukemia/myelodysplastic syndromes who relapse after allogeneic stem cell transplantation. Prospective studies to confirm optimal treatment options in this challenging patient population are required.

High-dose chemotherapy and autologous stem cell transplant compared with conventional chemotherapy for consolidation in newly diagnosed primary CNS lymphoma--a randomized phase III trial (MATRix).

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a highly aggressive Non-Hodgkin lymphoma (NHL) with rising incidence over the past 30 years in immunocompetent patients. Although outcomes have improved, PCNSL is still associated with inferior prognosis compared to systemic NHL. Many questions regarding the optimal therapeutic approach remain unanswered. METHODS/DESIGN: This is a randomized, open-label, international phase III trial with two parallel arms. We will recruit 250 patients with newly diagnosed PCNSL from approximately 35 centers within the networks of the German Cooperative PCNSL study group and the International Extranodal Lymphoma Study Group. All enrolled patients will undergo induction chemotherapy consisting of 4 cycles of rituximab 375 mg/m(2)/d (days 0 & 5), methotrexate 3.5 g/m(2) (d1), cytarabine 2 × 2 g/m(2)/d (d2-3), and thiotepa 30 mg/m(2) (d4) every 21 days. All patients will undergo stem-cell harvest after the second cycle. After 4 cycles of induction chemotherapy, patients achieving partial or complete response will be centrally randomized to 2 different consolidation treatments: (A) conventional-dose immuno chemotherapy with rituximab 375 mg/m(2) (d0), dexamethasone 40 mg/d (d1-3), etoposide 100 mg/m(2)/d (d1-3), ifosfamide 1500 mg/m(2)/d (d1-3) and carboplatin 300 mg/m(2) (d1) (R-DeVIC) or (B) high-dose chemotherapy with BCNU (or busulfan) and thiotepa followed by autologous stem cell transplantation (HCT-ASCT). The objective is to demonstrate superiority of HCT-ASCT compared to R-DeVIC with respect to progression-free survival (PFS, primary endpoint). Secondary endpoints include overall survival (OS), treatment response and treatment-related morbidities. Minimal follow-up after treatment completion is 24 months. DISCUSSION: The rationale for consolidation treatment in PCNSL is to eliminate residual lymphoma cells and to decrease the risk for relapse. This can be achieved by agents crossing the blood brain barrier either applied at conventional doses or at high doses requiring autologous stem cell support. HCT-ASCT has been shown to be feasible and highly effective in patients with newly-diagnosed PCNSL. However, it is unclear whether HCT-ASCT is really superior compared to conventional-dose chemotherapy after an intensified antimetabolites-based immunochemotherapy in patients with newly-diagnosed PCNSL. To answer this question, we designed this investigator initiated randomized phase III trial. TRIAL REGISTRATION: German clinical trials registry DRKS00005503 registered 22 April 2014 and ClinicalTrials.gov NCT02531841 registered 24 August 2015.

Multicenter experience in hematopoietic stem cell transplantation for serious complications of common variable immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is usually well controlled with immunoglobulin substitution and immunomodulatory drugs. A subgroup of patients has a complicated disease course with high mortality. For these patients, investigation of more invasive, potentially curative treatments, such as allogeneic hematopoietic stem cell transplantation (HSCT), is warranted. OBJECTIVE: We sought to define the outcomes of HSCT for patients with CVID. METHODS: Retrospective data were collected from 14 centers worldwide on patients with CVID receiving HSCT between 1993 and 2012. RESULTS: Twenty-five patients with CVID, which was defined according to international criteria, aged 8 to 50 years at the time of transplantation were included in the study. The indication for HSCT was immunologic dysregulation in the majority of patients. The overall survival rate was 48%, and the survival rate for patients undergoing transplantation for lymphoma was 83%. The major causes of death were treatment-refractory graft-versus-host disease accompanied by poor immune reconstitution and infectious complications. Immunoglobulin substitution was stopped in 50% of surviving patients. In 92% of surviving patients, the condition constituting the indication for HSCT resolved. CONCLUSION: This multicenter study demonstrated that HSCT in patients with CVID was beneficial in most surviving patients; however, there was a high mortality associated with the procedure. Therefore this therapeutic approach should only be considered in carefully selected patients in whom there has been extensive characterization of the immunologic and/or genetic defect underlying the CVID diagnosis. Criteria for patient selection, refinement of the transplantation protocol, and timing are needed for an improved outcome.

Achievement of complete remission predicts outcome of allogeneic haematopoietic stem cell transplantation in patients with chronic myelomonocytic leukaemia. A study of the Chronic Malignancies Working Party of the European Group for Blood and Marrow Transplantation.

The results of allogeneic stem cell transplantation (allo-SCT) in chronic myelomonocytic leukaemia (CMML) are usually reported together with other categories of myelodysplastic syndrome. We analysed transplantation outcome in 513 patients with CMML, with a median age of 53 years reported to the European Group for Blood and Marrow Transplantation. Conditioning was standard (n = 249) or reduced-intensity (n = 226). Donors were human leucocyte antigen-related (n = 285) or unrelated (n = 228). Disease status at transplantation was complete remission (CR) in 122 patients, no CR in 344, and unknown in 47. Engraftment was successful in 95%. Grades 2-4 acute graft-versus-host disease (GvHD) occurred in 33% of the patients and chronic GvHD was reported in 24%. The 4-year cumulative incidence of non-relapse mortality was 41% and 32% for relapse, resulting in a 4-year estimated relapse-free and overall survival (OS) of 27% and 33%, respectively. Patients transplanted in CR had lower probability for non-relapse death (P = 0·002) and longer relapse-free and OS (P = 0·001 and P = 0·005, respectively). In multivariate analysis the only significant prognostic factor for survival was the presence of CR at transplantation (P = 0·005). Allo-SCT remains a curative treatment option for patients with CMML and should preferably be performed early after diagnosis or after establishing the best possible remission status.

A fast and simple approach for the simultaneous detection of hematopoietic chimerism, NPM1, and FLT3-ITD mutations after allogeneic stem cell transplantation.

Hematopoietic chimerism can be used as a tool for patient management after allogeneic hematopoietic stem cell transplantation (HSCT). An increase in the proportion of recipient cells after transplantation is strongly associated with relapse in chronic myeloid leukemia. However, in acute myeloid leukemia (AML) the significance of increasing mixed chimerism (MC) as a predictive marker for relapse is less clear. Several mutations frequently found in AML have been employed for minimal residual disease detection and relapse prediction. Therefore, a combined analysis of hematopoietic chimerism and of the molecular aberrations found in AML could be used to improve MC characterization. We developed a multiplex PCR for use in the simultaneous detection of hematopoietic chimerism and mutations in nucleophosmin (NPM1) and fms-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD). A total of 303 samples from 20 AML patients were analyzed after HSCT. The microsatellite markers used for hematopoietic chimerism detection were D1S80, D7S1517, D4S2366, THO1, and SE33. A total of 149 samples from 18 patients showed MC with a mean detection time of 9.7 months. From the 18 patients with MC, in 6 of the patients, no FLT3-ITD or NPM1 mutation was found at any time point tested, and these patients remained in complete hematological remission. In 12 patients with MC, FLT3-ITD and NPM1 mutations were found, and these patients showed signs of hematological relapse. Our combined analysis of NPM1/FLT3-ITD mutations and hematopoietic chimerism improved the characterization of patients with MC after HSCT. The present approach may be further expanded by combining additional mutations found in AML with hematopoietic chimerism detection.

High-dose chemotherapy and autologous haematopoietic stem-cell transplantation in older, fit patients with primary diffuse large B-cell CNS lymphoma (MARTA): a single-arm, phase 2 trial.

BACKGROUND: Available treatments for older patients with primary diffuse large B-cell CNS lymphoma (PCNSL) offer progression-free survival of up to 16 months. We aimed to investigate an intensified treatment of high-dose chemotherapy and autologous haematopoietic stem-cell transplantation (HSCT) in older patients with PCNSL. METHODS: MARTA was a prospective, single-arm, phase 2 study done at 15 research hospitals in Germany. Patients aged 65 years or older with newly diagnosed, untreated PCNSL were enrolled if they had an Eastern Cooperative Oncology Group performance status of 0-2 and were fit for high-dose chemotherapy and autologous HSCT. Induction treatment consisted of two 21-day cycles of high-dose intravenous methotrexate 3·5 g/m2 (day 1), intravenous cytarabine 2 g/m2 twice daily (days 2 and 3), and intravenous rituximab 375 mg/m2 (days 0 and 4) followed by high-dose chemotherapy with intravenous rituximab 375 mg/m2 (day -8), intravenous busulfan 3·2 mg/kg (days -7 and -6), and intravenous thiotepa 5 mg/kg (days -5 and -4) plus autologous HSCT. The primary endpoint was progression-free survival at 12 months in all patients who met eligibility criteria and started treatment. The study was registered with the German clinical trial registry, DRKS00011932, and recruitment is complete. FINDINGS: Between Nov 28, 2017, and Sept 16, 2020, 54 patients started induction treatment and 51 were included in the full analysis set. Median age was 71 years (IQR 68-75); 27 (53%) patients were female and 24 (47%) were male. At a median follow-up of 23·0 months (IQR 16·8-37·4), 23 (45%) of 51 patients progressed, relapsed, or died. 12-month progression-free survival was 58·8% (80% CI 48·9-68·2; 95% CI 44·1-70·9). During induction treatment, the most common grade 3-5 toxicities were thrombocytopenia and leukopenia (each in 52 [96%] of 54 patients). During high-dose chemotherapy and autologous HSCT, the most common grade 3-5 toxicity was leukopenia (37 [100%] of 37 patients). Treatment-related deaths were reported in three (6%) of 54 patients, all due to infectious complications. INTERPRETATION: Although the primary efficacy threshold was not met, short induction followed by high-dose chemotherapy and autologous HSCT is active in selected older patients with PCNSL and could serve as a benchmark for comparative trials. FUNDING: Else Kröner-Fresenius Foundation, Riemser Pharma, and Medical Center-University of Freiburg.

Validation of the transplant conditioning intensity (TCI) index for allogeneic hematopoietic cell transplantation.

The intensity of the conditioning regimen given before allogeneic hematopoietic cell transplantation (allo-HCT) can vary substantially. To confirm the ability of the recently developed transplant conditioning intensity (TCI) score to stratify the preparative regimens of allo-HCT, we used an independent and contemporary patient cohort of 4060 transplant recipients with acute myeloid leukemia meeting inclusion criteria from the discovery study (allo-HCT in first complete remission, matched donor), but who were allografted in a more recent period (2018-2021) and were one decade older (55-75 years, median 63.4 years), we assigned them to a TCI category (low n = 1934, 48%; intermediate n = 1948, 48%, high n = 178, 4%) according to the calculated TCI score ([1-2], [2.5-3.5], [4-6], respectively), and examined the validity of the TCI category in predicting early non-relapse mortality (NRM), 2-year NRM and relapse (REL). In the unadjusted comparison, the TCI index provided a significant risk stratification for d100 and d180 NRM, NRM and REL risk. In the multivariate analysis adjusted for significant variables, there was an independent association of TCI with early NRM, NRM and REL. In summary, we confirm in contemporary treated patients that TCI reflects the conditioning regimen related morbidity and anti-leukemic efficacy satisfactorily and across other established prognostic factors.

Conjunctival HLA-DR and CD8 expression detected by impression cytology in ocular graft versus host disease.

PURPOSE: To assess the expression of human leucocyte antigen (HLA)-DR in epithelial cells and cluster of differentiation (CD8)-positive lymphocytes as possible markers of chronic ocular graft versus host disease (cGvHD) after hematological stem cell transplantation (HSCT). METHODS: Twenty-seven consecutive patients with dry-eye symptoms following HSCT (24 [89%] with peripheral blood stem cell transplantation and 3 [11%] with bone marrow transplants; 17 [63%] familiar allogenic grafts) and 19 age-matched controls were included. Conjunctival impression cytology specimens were stained for HLA-DR, cytokeratin 19, and CD8. Oxford grading scale, blinking frequency, Schirmer test, tear film break-up time (TBUT), and Ocular Surface Disease Index (OSDI) were also recorded. Wilcoxon nonparametric testing was used to compare controls and HSCT recipients and to assess HSCT recipient subgroups with and without clinical cGVHD. RESULTS: Eighteen patients showed clinical signs of ocular cGVHD. TBUT and Schirmer test scores were significantly lower in patients, while Oxford grades and OSDI were significantly higher than in controls. Epithelial HLA-DR expression was generally higher in HSCT recipients than in controls, but it did not correlate with ocular cGVHD status. CD8-positive lymphocytes were identified in five patients with ocular cGvHD and one control. CONCLUSIONS: A strong HLA-DR expression as detected by impression cytology appears to indicate a general HSCT response and fails to predict ocular cGVHD. However, the detection of CD8-positive lymphocytes using impression cytology was frequently associated with ocular cGvHD. Our data warrant further evaluation of CD8 expression in impression cytology, along with comparison to conjunctival biopsies and brush cytology, as impression cytology may offer a less invasive strategy for assessing cGVHD status.

Body mass index and bioelectrical impedance phase angle as potentially modifiable nutritional markers are independent risk factors for outcome in allogeneic hematopoietic cell transplantation.

Beside many risk factors in patients considered for alloHCT, only body mass index (BMI) as a broad marker of nutritional status has prognostic value in these patients. This is the first prospective study to investigate the validity of further nutritional markers: adjusted BMI, normalized for gender and age; Subjective Global Assessment questionnaire and standardized phase angle, normalized for gender, age and BMI in 105 patients as independent risk factors for outcomes [overall survival (OS), non-relapse mortality (NRM), relapse mortality (RM), progression-free survival (PFS)] until 2 years after alloHCT. In Cox proportional-hazards regression models, we included a variety of accepted risk factors. The two most influential pre-transplant risk factors identified and associated with similarly increased hazard ratios (HR) for OS, RM, and PFS were a low-standardized phase angle (HR = 1.97, P = 0.043; HR = 3.18, P = 0.017, and HR = 1.91, P = 0.039) and advanced disease. Under- and overweight according BMI percentiles (≤10th; ≥90th) revealed associations with increased risk of NRM (HR = 2.90, P = 0.018; HR = 3.02, P = 0.062), although only low BMI was weakly associated with OS (HR = 1.82, P = 0.09). In conclusion, our results demonstrate that pre-transplant phase angle is an independent predictor for 2-year outcomes in these patients. Further investigation is necessary to demonstrate whether the theoretically modifiable phase angle can be increased by physical training combined with nutritional support, and if this improves outcome after alloHCT.

An internal validation approach and quality control on hematopoietic chimerism testing after allogeneic hematopoietic cell transplantation.

BACKGROUND: Hematopoietic chimerism analysis is important in the follow-up of patients undergoing allogeneic stem cell transplantation. PCR of short tandem repeats is mainly used for monitoring chimerism after transplantation. Validation studies and precision of assay's performance with respect to different mixed chimerism stages is not fully addressed. The aim of the present study was to assess the impact of several microsatellite analytical parameters in the quantification of hematopoietic chimerism after allogeneic hematopoietic stem cell transplantation and to analyze the overall analytical process through the application of internal quality control procedures. METHODS: Artificial DNA mixtures prepared in known proportions and patients samples were analyzed using three microsatellites, together with amplification of amelogenin gene and fluorescence in situ hybridization (FISH) for X and Y chromosomes. Limit of detection, analytical and clinical sensitivity, stochastic threshold and precision profiling was established. Levey-Jennings charts and Westgard rules were applied for quality control evaluation. RESULTS: Analytical and clinical sensitivity of the microsatellite markers was between 0.5% and 1.6%. Amelogenin detection and FISH for X and Y chromosomes showed a similar sensitivity. Severe allelic imbalance resulted in up to 50% difference between the calculated and corrected mixed chimerism. Systematic errors were identified using Levey-Jennings charts and Westgard rules. CONCLUSIONS: Analysis of hematopoietic chimerism performance is a critical step to better understand potential intrinsic errors that may impact the final hematopoietic chimerism results. Implementing quality control tools, such as Levey-Jennings charts together with Westgard rules can identify systematic and random errors so corrective actions can be performed.

Clofarabine-containing conditioning regimen for allo-SCT in AML/ALL patients: a survey from the Acute Leukemia Working Party of EBMT.

Clofarabine (CLO), a second-generation purine analogue, has demonstrated an efficient anti-leukemia activity while showing a favorable toxicity profile. This retrospective multicenter report assessed the outcome of 90 patients who received a CLO-containing conditioning regimen before allo-SCT for AML (n = 69) or ALL (n = 21). Median age was 42 yr at transplant. The majority of cases (n = 66) presented with an active disease at transplant while 38 patients had received previous transplantation(s). A total of 88 and two patients received a reduced-intensity conditioning or a myeloablative regimen, respectively. Engraftment was achieved in 97% of evaluable patients. With a median follow-up of 14 months (range, 1-45), the 2-year OS, LFS, relapse, and NRM rates were 28 ± 5%, 23 ± 5%, 41 ± 6%, and 35 ± 5%, respectively. When comparing AML and ALL patients, OS and LFS were significantly higher for AML (OS, 35 ± 6% vs. 0%, P < 0.0001); LFS: 30 ± 6% vs. 0%, P < 0.0001). In a Cox multivariate analysis, an AML diagnosis was the only factor associated with a better LFS (HR = 0.37; 95%CI, 0.21-0.66; P = 0.001). We conclude that a CLO-containing conditioning regimen prior to allo-SCT might be an effective treatment. Prospective studies are needed to evaluate the potential role of CLO as part of conditioning regimens in acute leukemias.

Long-term results and GvHD after prophylactic and preemptive donor lymphocyte infusion after allogeneic stem cell transplantation for acute leukemia.

We report on 318 patients with acute leukemia, receiving donor lymphocyte infusion (DLI) in complete hematologic remission (CHR) after allogeneic stem cell transplantation (alloSCT). DLI were applied preemptively (preDLI) for minimal residual disease (MRD, n = 23) or mixed chimerism (MC, n = 169), or as prophylaxis in high-risk patients with complete chimerism and molecular remission (proDLI, n = 126). Median interval from alloSCT to DLI1 was 176 days, median follow-up was 7.0 years. Five-year cumulative relapse incidence (CRI), non-relapse mortality (NRM), leukemia-free and overall survival (LFS/OS) of the entire cohort were 29.1%, 12.7%, 58.2%, and 64.3%. Cumulative incidences of acute graft-versus-host disease (aGvHD) grade II-IV°/chronic GvHD were 11.9%/31%. Nineteen patients (6%) died from DLI-induced GvHD. Age ≥60 years (p = 0.046), advanced stage at transplantation (p = 0.003), shorter interval from transplantation (p = 0.018), and prior aGvHD ≥II° (p = 0.036) were risk factors for DLI-induced GvHD. GvHD did not influence CRI, but was associated with NRM and lower LFS/OS. Efficacy of preDLI was demonstrated by decreasing MRD/increasing blood counts in 71%, and increasing chimerism in 70%. Five-year OS after preDLI for MRD/MC was 51%/68% among responders, and 37% among non-responders. The study describes response and outcome of DLI in CHR and helps to identify candidates without increased risk of severe GvHD.

Reduced-toxicity conditioning with treosulfan and fludarabine in allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes: final results of an international prospective phase II trial.

BACKGROUND: An alternative reduced-toxicity conditioning regimen for allogeneic transplantation, based on treosulfan and fludarabine, has recently been identified. The rationale for this study was to investigate the efficacy and safety of this regimen prospectively in patients with a primary myelodysplastic syndrome. DESIGN AND METHODS: A total of 45 patients with primary myelodysplastic syndromes were conditioned with 3×14 g/m(2) treosulfan and 5×30 mg/m(2) fludarabine followed by allogeneic hematopoietic stem cell transplantation. Subtypes of myelodysplastic syndromes were refractory anemia with excess blasts-2 (44%), refractory cytopenia with multilineage dysplasia (27%), refractory anemia (9%), refractory anemia with ringed sideroblasts (4%), refractory cytopenia with multilineage dysplasia and ringed sideroblasts (4%), refractory anemia with excess blasts-1 (2%), and myelodysplastic syndrome with isolated del (5q) (2%). The myelodysplastic syndrome was unclassified in 7% of the patients. Forty-seven percent of the patients had a favorable karyotype, 29% an unfavorable one, and 18% an intermediate karyotype. Patients were evaluated for engraftment, adverse events, graft-versus-host disease, non-relapse mortality, relapse incidence, overall survival and disease-free survival. RESULTS: All but one patient showed primary engraftment of neutrophils after a median of 17 days. Non-hematologic adverse events of grade III-IV in severity included mainly infections and gastrointestinal symptoms (80% and 22% of the patients, respectively). Acute graft-versus-host disease grade II-IV developed in 24%, and extensive chronic graft-versus-host disease in 28% of the patients. After a median follow-up of 780 days, the 2-year overall and disease-free survival estimates were 71% and 67%, respectively. The 2-year cumulative incidences of non-relapse mortality and relapse were 17% and 16%, respectively. CONCLUSIONS: Our safety and efficacy data suggest that treosulfan-based conditioning therapy is a promising treatment option for patients with myelodysplastic syndromes. clinicaltrials.gov identifier: NCT01062490.

Treosulfan or busulfan plus fludarabine as conditioning treatment before allogeneic haemopoietic stem cell transplantation for older patients with acute myeloid leukaemia or myelodysplastic syndrome (MC-FludT.14/L): a randomised, non-inferiority, phase 3 trial.

BACKGROUND: Further improvement of preparative regimens before allogeneic haemopoietic stem cell transplantation (HSCT) is an unmet medical need for the growing number of older or comorbid patients with acute myeloid leukaemia or myelodysplastic syndrome. We aimed to evaluate the efficacy and safety of conditioning with treosulfan plus fludarabine compared with reduced-intensity busulfan plus fludarabine in this population. METHODS: We did an open-label, randomised, non-inferiority, phase 3 trial in 31 transplantation centres in France, Germany, Hungary, Italy, and Poland. Eligible patients were 18-70 years, had acute myeloid leukaemia in first or consecutive complete haematological remission (blast counts <5% in bone marrow) or myelodysplastic syndrome (blast counts <20% in bone marrow), Karnofsky index of 60% or higher, and were indicated for allogeneic HSCT but considered at an increased risk for standard myeloablative preparative regimens based on age (≥50 years), an HSCT-specific comorbidity index of more than 2, or both. Patients were randomly assigned (1:1) to receive either intravenous 10 g/m2 treosulfan daily applied as a 2-h infusion for 3 days (days -4 to -2) or 0·8 mg/kg busulfan applied as a 2-h infusion at 6-h intervals on days -4 and -3. Both groups received 30 mg/m2 intravenous fludarabine daily for 5 days (days -6 to -2). The primary outcome was event-free survival 2 years after HSCT. The non-inferiority margin was a hazard ratio (HR) of 1·3. Efficacy was assessed in all patients who received treatment and completed transplantation, and safety in all patients who received treatment. The study is registered with EudraCT (2008-002356-18) and ClinicalTrials.gov (NCT00822393). FINDINGS: Between June 13, 2013, and May 3, 2016, 476 patients were enrolled (240 in the busulfan group received treatment and transplantation, and in the treosulfan group 221 received treatment and 220 transplanation). At the second preplanned interim analysis (Nov 9, 2016), the primary endpoint was met and trial was stopped. Here we present the final confirmatory analysis (data cutoff May 31, 2017). Median follow-up was 15·4 months (IQR 8·8-23·6) for patients treated with treosulfan and 17·4 months (6·3-23·4) for those treated with busulfan. 2-year event-free survival was 64·0% (95% CI 56·0-70·9) in the treosulfan group and 50·4% (42·8-57·5) in the busulfan group (HR 0·65 [95% CI 0·47-0·90]; p<0·0001 for non-inferiority, p=0·0051 for superiority). The most frequently reported grade 3 or higher adverse events were abnormal blood chemistry results (33 [15%] of 221 patients in the treosulfan group vs 35 [15%] of 240 patients in the busulfan group) and gastrointestinal disorders (24 [11%] patients vs 39 [16%] patients). Serious adverse events were reported for 18 (8%) patients in the treosulfan group and 17 (7%) patients in the busulfan group. Causes of deaths were generally transplantation-related. INTERPRETATION: Treosulfan was non-inferior to busulfan when used in combination with fludarabine as a conditioning regimen for allogeneic HSCT for older or comorbid patients with acute myeloid leukaemia or myelodysplastic syndrome. The improved outcomes in patients treated with the treosulfan-fludarabine regimen suggest its potential to become a standard preparative regimen in this population. FUNDING: medac GmbH.