Combination romidepsin and azacitidine therapy is well tolerated and clinically active in adults with high-risk acute myeloid leukaemia ineligible for intensive chemotherapy.

Azacitidine (AZA) is important in the management of patients with acute myeloid leukaemia (AML) who are ineligible for intensive chemotherapy. Romidepsin (ROM) is a histone deacetylase inhibitor which synergises with AZA in vitro. The ROMAZA trial established the maximum tolerated dose (MTD) of combined ROM/AZA therapy in patients with AML, as ROM 12 mg/m2 on Days 8 and 15, with AZA 75 mg/m2 administered for 7/28 day cycle. Nine of the 38 (23·7%) patients treated at the MTD were classified as responders by Cycle 6 (best response: complete remission [CR]/incomplete CR n = 7, partial response n = 2). Correlative next-generation sequencing studies demonstrated important insights into therapy resistance.

Disease Prevention Not Decolonization: A Model for Fecal Microbiota Transplantation in Patients Colonized With Multidrug-resistant Organisms.

Fecal microbiota transplantation (FMT) yields variable intestinal decolonization results for multidrug-resistant organisms (MDROs). This study showed significant reductions in antibiotic duration, bacteremia, and length of stay in 20 patients colonized/infected with MDRO receiving FMT (compared with pre-FMT history, and a matched group not receiving FMT), despite modest decolonization rates.

A Multispecies Cluster of GES-5 Carbapenemase-Producing Enterobacterales Linked by a Geographically Disseminated Plasmid.

BACKGROUND: Early and accurate treatment of infections due to carbapenem-resistant organisms is facilitated by rapid diagnostics, but rare resistance mechanisms can compromise detection. One year after a Guiana Extended-Spectrum (GES)-5 carbapenemase-positive Klebsiella oxytoca infection was identified by whole-genome sequencing (WGS; later found to be part of a cluster of 3 cases), a cluster of 11 patients with GES-5-positive K. oxytoca was identified over 18 weeks in the same hospital. METHODS: Bacteria were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, antimicrobial susceptibility testing followed European Committee on Antimicrobial Susceptibility Testing guidelines. Ertapenem-resistant isolates were referred to Public Health England for characterization using polymerase chain reaction (PCR) detection of GES, pulsed-field gel electrophoresis (PFGE), and WGS for the second cluster. RESULTS: The identification of the first GES-5 K. oxytoca isolate was delayed, being identified by WGS. Implementation of a GES-gene PCR informed the occurrence of the second cluster in real time. In contrast to PFGE, WGS phylogenetic analysis refuted an epidemiological link between the 2 clusters; it also suggested a cascade of patient-to-patient transmission in the later cluster. A novel GES-5-encoding plasmid was present in K. oxytoca, Escherichia coli, and Enterobacter cloacae isolates from unlinked patients within the same hospital group and in human and wastewater isolates from 3 hospitals elsewhere in the United Kingdom. CONCLUSIONS: Genomic sequencing revolutionized the epidemiological understanding of the clusters; it also underlined the risk of covert plasmid propagation in healthcare settings and revealed the national distribution of the resistance-encoding plasmid. Sequencing results also informed and led to the ongoing use of enhanced diagnostic tests for detecting carbapenemases locally and nationally.

Association of uric acid levels before start of conditioning with mortality after allogeneic hematopoietic stem cell transplantation - a prospective, non-interventional study of the EBMT Transplant Complication Working Party.

Uric acid is a danger signal contributing to inflammation. Its relevance to allogeneic stem cell transplantation (alloSCT) derives from preclinical models where the depletion of uric acid led to improved survival and reduced graft-versus-host disease (GvHD). In a clinical pilot trial, peri-transplant uric acid depletion reduced acute GvHD incidence. This prospective international multicenter study aimed to investigate the association of uric acid serum levels before start of conditioning with alloSCT outcome. We included patients with acute leukemia, lymphoma or myelodysplastic syndrome receiving a first matched sibling alloSCT from peripheral blood, regardless of conditioning. We compared outcomes between patients with high and low uric acid levels with univariate- and multivariate analysis using a cause-specific Cox model. Twenty centers from 10 countries reported data on 366 alloSCT recipients. There were no significant differences in terms of baseline comorbidity and disease stage between the high- and low uric acid group. Patients with uric acid levels above median measured before start of conditioning did not significantly differ from the remaining in terms of acute GvHD grades II-IV incidence (Hazard ratio [HR] 1.5, 95% Confidence interval [CI]: 1.0-2.4, P=0.08). However, they had significantly shorter overall survival (HR 2.8, 95% CI: 1.7-4.7, P<0.0001) and progression free survival (HR 1.6, 95% CI: 1.1-2.4, P=0.025). Non-relapse mortality was significantly increased in alloSCT recipients with high uric acid levels (HR 2.7, 95% CI: 1.4-5.0, P=0.003). Finally, the incidence of relapse after alloSCT was increased in patients with higher uric acid levels (HR 1.6, 95% CI: 1.0-2.5, P=0.04). We conclude that high uric acid levels before the start of conditioning correlate with increased mortality after alloSCT.

Allogeneic hematopoietic cell transplantation for primary refractory acute lymphoblastic leukemia: A report from the Acute Leukemia Working Party of the EBMT.

BACKGROUND: Patients with primary refractory acute lymphoblastic leukemia (PREF ALL) who fail to achieve a complete remission (CR) after ≥2 courses of chemotherapy have a dismal prognosis without undergoing allogeneic hematopoietic cell transplantation (HCT). To the authors' knowledge, there currently are no data regarding factors influencing transplantation outcomes. METHODS: The authors retrospectively studied outcomes of transplantation for cases of PREF ALL reported to European Society for Blood and Marrow Transplantation registry. Eligibility criteria for the current analysis included adult patients who underwent their first HCT for PREF ALL between 2000 and 2012. PREF disease was defined as the failure to achieve a morphological CR after ≥2 courses of induction chemotherapy. RESULTS: Data regarding 86 adult patients were analyzed. With a median follow-up of 106 months, the probability of survival was 36% at 2 years and 23% at 5 years. The probability of leukemia-free survival was 28% and 17%, respectively, and the probability of nonrecurrence mortality was 20% and 29%, respectively, at 2 years and 5 years. For 66 patients who achieved a CR (77%), the survival at 2 years and 5 years was 36% and 29%, respectively. In multivariate analysis, use of total body irradiation was found to be associated with improved survival. Total body irradiation and infusion of female hematopoietic cells into male recipients was associated with improved leukemia-free survival. These findings were incorporated into a scoring system that identified 3 groups (those with 2, 1, or no prognostic factors) with survival rates of 57%, 22%, and 8%, respectively. CONCLUSIONS: Although overall these patients would clearly benefit from the introduction of novel antileukemic therapies, the data from the current study support the use of allogeneic HCT in selected patients with PREF ALL. Cancer 2017;123:1965-1970. © 2017 American Cancer Society.

BKV-specific T cells in the treatment of severe refractory haemorrhagic cystitis after HLA-haploidentical haematopoietic cell transplantation.

BACKGROUND: Haemorrhagic cystitis caused by BK virus (BKV) is a known complication of allogeneic haematopoietic cell transplantation (HCT) and is relatively common following HLA-haploidentical transplantation. Adoptive immunotransfer of virus-specific T cells from the donor is a promising therapeutic approach, although production of these cells is challenging, particularly when dealing with low-frequency T cells such as BKV-specific T cells. CASE REPORT: Here, we present a patient who, following haploidentical HCT, developed severe BKV haemorrhagic cystitis, resistant to standard therapy. He responded well to adoptive transfer of donor cells enriched in BKV-specific T cells using the new second-generation CliniMACS Prodigy and the Cytokine Capture System from Miltenyi Biotec. Treatment led to full resolution of both the symptoms and viraemia without unwanted complications. CONCLUSION: Our observations suggest that use of products enriched with BKV-specific T cells generated using this system is safe and efficient in HLA-haploidentical HCT where BKV cystitis can be a serious complication.

Graft invariant natural killer T-cell dose predicts risk of acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation.

Invariant natural killer T (iNKT) cells are powerful immunomodulatory cells that in mice regulate a variety of immune responses, including acute GVHD (aGVHD). However, their clinical relevance and in particular their role in clinical aGVHD are not known. We studied whether peripheral blood stem cell (PBSC) graft iNKT-cell dose affects on the occurrence of clinically significant grade II-IV aGVHD in patients (n = 57) undergoing sibling, HLA-identical allogeneic HSCT. In multivariate analysis, CD4(-) iNKT-cell dose was the only graft parameter to predict clinically significant aGVHD. The cumulative incidence of grade II-IV aGVHD in patients receiving CD4(-) iNKT-cell doses above and below the median were 24.2% and 71.4%, respectively (P = .0008); low CD4(-) iNKT-cell dose was associated with a relative risk of grade II-IV aGVHD of 4.27 (P = .0023; 95% CI, 1.68-10.85). Consistent with a role of iNKT cells in regulating aGVHD, in mixed lymphocyte reaction assays, CD4(-) iNKT cells effectively suppressed T-cell proliferation and IFN-γ secretion in a contact-dependent manner. In conclusion, higher doses of CD4(-) iNKT cells in PBSC grafts are associated with protection from aGVHD. This effect could be harnessed for prevention of aGVHD.

Leukemia-induced phenotypic and functional defects in natural killer cells predict failure to achieve remission in acute myeloid leukemia.

The majority of patients with acute myeloid leukemia will relapse, and older patients often fail to achieve remission with induction chemotherapy. We explored the possibility that leukemic suppression of innate immunity might contribute to treatment failure. Natural killer cell phenotype and function was measured in 32 consecutive acute myeloid leukemia patients at presentation, including 12 achieving complete remission. Compared to 15 healthy age-matched controls, natural killer cells from acute myeloid leukemia patients were abnormal at presentation, with downregulation of the activating receptor NKp46 (P=0.007) and upregulation of the inhibitory receptor NKG2A (P=0.04). Natural killer cells from acute myeloid leukemia patients had impaired effector function against autologous blasts and K562 targets, with significantly reduced CD107a degranulation, TNF-α and IFN-γ production. Failure to achieve remission was associated with NKG2A overexpression and reduced TNF-α production. These phenotypic and functional abnormalities were partially restored in the 12 patients achieving remission. In vitro co-incubation of acute myeloid leukemia blasts with natural killer cells from healthy donors induced significant impairment in natural killer cell TNF-α and IFN-γ production (P=0.02 and P=0.01, respectively) against K562 targets and a trend to reduced CD107a degranulation (P=0.07). Under transwell conditions, the inhibitory effect of AML blasts on NK cytotoxicity and effector function was still present, and this inhibitory effect was primarily mediated by IL-10. These results suggest that acute myeloid leukemia blasts induce long-lasting changes in natural killer cells, impairing their effector function and reducing the competence of the innate immune system, favoring leukemia survival.

Ciprofloxacin prophylaxis during haematopoietic cell transplantation: a role for use in patients with germ cell tumours?

Introduction. Fluoroquinolone prophylaxis during haematopoietic cell transplantation (HCT) can lead to antimicrobial resistance (AMR). Identifying the groups of patients that have the highest likelihood of benefiting from prophylactic antimicrobials is important for antimicrobial stewardship (AMS).Hypothesis. We aimed to identify groups of HCT recipients that have the highest likelihood of benefiting from prophylactic fluroquinolones.Methods. All admissions for HCT in a tertiary centre between January 2020 and December 2022 (N = 400) were retrospectively studied. Allogeneic HCT (allo-HCT) recipients had prophylaxis with ciprofloxacin during the chemotherapy-induced neutropenia, while autologous HCT (auto-HCT) recipients did not. Bacteraemias were recorded when non-contaminant bacterial pathogens were isolated in blood cultures.Results. Allo-HCT was performed for 43.3 % (173/400) of patients and auto-HCT was performed for 56.7 % (227/400). A bacteraemia was documented in 28.3 % (113/400) of cases. Allo-HCT recipients were more likely to have a Gram-positive bacteraemia (20.8%, 36/173, vs 10.1%, 23/227, P = 0.03), while a difference was not observed for Gram-negative bacteraemias (18.5%, 32/173 vs 18.1%, 41/227, P = 0.91). Among auto-HCT recipients not receiving ciprofloxacin prophylaxis, patients with germ cell tumours had the highest probability (P for trend 0.09) of recording any bacteraemia (43.5%, 10/23) followed by patients with lymphomas (32.5%, 13/40), other auto-HCT indications (22.2%, 2/9), multiple myeloma (22.1%, 29/131) and multiple sclerosis (12.5%, 3/24). The higher number of bacteraemias in patients with germ cell tumours was primarily driven by Gram-negative pathogens.Conclusions. Ciprofloxacin prophylaxis was associated with a reduced incidence of Gram-negative bacteraemias in allo-HCT recipients. Auto-HCT recipients due to germ cell tumours, not receiving ciprofloxacin prophylaxis, recorded the highest incidence of bacteraemias and represent a possible target group for this intervention.

The effect of ciprofloxacin prophylaxis during haematopoietic cell transplantation on infection episodes, exposure to treatment antimicrobials and antimicrobial resistance: a single-centre retrospective cohort study.

Objectives: Fluroquinolone prophylaxis during haematopoietic cell transplantation (HCT) remains contentious. We aimed to determine its effectiveness and association with exposure to treatment antimicrobials and antimicrobial resistance. Methods: All admission episodes for HCT (N = 400 , 372 unique patients) in a tertiary centre between January 2020 and December 2022 were studied. Allogeneic HCT (allo-HCT) recipients received prophylaxis with ciprofloxacin during chemotherapy-induced neutropenia, while autologous HCT (auto-HCT) recipients did not. Results: Allo-HCT was performed for 43.3% (173/400) of patients, auto-HCT for 56.7% (227/400). Allo-HCT was associated with an average of 1.01 fewer infection episodes per 100 admission days (95% CI 0.62-1.40, P < 0.001) compared with auto-HCT. In allo-HCT, the total exposure to all antimicrobials was higher [+24.8 days of therapy (DOT)/100 admission days, P < 0.001], as was exposure to ciprofloxacin (+40.5 DOT/100 admission days, P < 0.001). By contrast, exposure to meropenem (-4.5 DOT/100 admission days, P = 0.02), piperacillin/tazobactam (-5.2 DOT/100 admission days, P < 0.001), aminoglycosides (-4.5 DOT/100 admission days, P < 0.001) and glycopeptides (-6.4 DOT/100 admission days, P < 0.001) was reduced. Enterobacteriaceae isolated during allo-HCT were more resistant to ciprofloxacin (65.5%, 19/29 versus 6.1%, 2/33, P < 0001), ceftriaxone (65.5%, 19/29 versus 9.1%, 3/33, P < 0.001), other antimicrobial classes. Vancomycin-resistant enterococci were more common in allo-HCT recipients (11%, 19/173 versus 0.9%, 2/227, P < 0.001). Inpatient mortality during allo- and auto-HCT was 9.8% (17/173) and 0.4% (1/227). respectively (P < 0.001). Conclusions: Ciprofloxacin prophylaxis in allo-HCT was associated with fewer infection episodes and reduced exposure to treatment antimicrobials. Mortality in auto-HCT remained low. A significant burden of antimicrobial resistance was detected in allo-HCT recipients.

Three decades of transplantation for chronic myeloid leukemia: what have we learned?

Last year marked 30 years of hematopoietic stem cell transplantation as a curative treatment of chronic myeloid leukemia (CML). Initially studies used stem cells from identical twins but techniques rapidly developed to use cells first from HLA-identical siblings and later unrelated donors. During the 1990s CML became the most frequent indication for allogeneic transplantation worldwide. This, together with the relative biologic homogeneity of CML in chronic phase, its responsiveness to graft-versus-leukemia effect and the ability to monitor low level residual disease placed CML at the forefront of research into different strategies of stem cell transplantation. The introduction of BCR-ABL1 tyrosine kinase inhibitors during the last decade resulted in long-term disease control in the majority of patients with CML. In those who fail to respond and/or develop intolerance to these agents, transplantation remains an effective therapeutic solution. The combination of tyrosine kinase inhibitors with transplantation is an exciting new strategy and it provides inspiration for similar approaches in other malignancies.

Lymphodepletion chemotherapy followed by donor leukocytes for post-transplantation relapse of myelofibrosis after previous donor leukocyte infusion failure.

Treatment of relapse after allogenic stem cell transplantation (allo-SCT) is challenging. The efficacy of donor leukocyte infusions (DLI) is excellent in chronic phase chronic myeloid leukaemia but limited in other disorders. We present a patient who relapsed 10 months after reduced intensity conditioning allo-SCT for a myelodysplastic/ myeloproliferative neoplasm with myelofibrosis despite receiving escalating doses of DLI for incomplete chimerism. He finally achieved complete remission with full whole blood and T-cell donor chimerism after DLI preceded by lymphodepletion chemotherapy. This case demonstrates that chemotherapy prior to DLI is a useful approach for treating relapses of relatively slowly progressive diseases, such as myeloproliferative diseases or myelodysplastic syndromes.

Constructing training set using distance between learnt graphical models of time series data on patient physiology, to predict disease scores.

Interventional endeavours in medicine include prediction of a score that parametrises a new subject's susceptibility to a given disease, at the pre-onset stage. Here, for the first time, we provide reliable learning of such a score in the context of the potentially-terminal disease VOD, that often arises after bone marrow transplants. Indeed, the probability of surviving VOD, is correlated with early intervention. In our work, the VOD-score of each patient in a retrospective cohort, is defined as the distance between the (posterior) probability of a random graph variable-given the inter-variable partial correlation matrix of the time series data on variables that represent different aspects of patient physiology-and that given such time series data of an arbitrarily-selected reference patient. Such time series data is recorded from a pre-transplant to a post-transplant time, for each patient in this cohort, though the data available for distinct patients bear differential temporal coverage, owing to differential patient longevities. Each graph is a Soft Random Geometric Graph drawn in a probabilistic metric space, and the computed inter-graph distance is oblivious to the length of the time series data. The VOD-score learnt in this way, and the corresponding pre-transplant parameter vector of each patient in this retrospective cohort, then results in the training data, using which we learn the function that takes VOD-score as its input, and outputs the vector of pre-transplant parameters. We model this function with a vector-variate Gaussian Process, the covariance structure of which is kernel parametrised. Such modelling is easier than if the score variable were the output. Then for any prospective patient, whose pre-transplant variables are known, we learn the VOD-score (and the hyperparameters of the covariance kernel), using Markov Chain Monte Carlo based inference.

Non-T-depleted haploidentical transplantation with post-transplant cyclophosphamide in patients with secondary versus de novo AML in first complete remission: a study from the ALWP/EBMT.

We compared outcomes of adult patients with secondary acute myeloid leukemia (sAML) versus de novo AML after non-T-depleted haploidentical stem cell transplant (HaploSCT) with post-transplant cyclophosphamide (PTCy). Seventeen hundred and eleven AML patients (sAML-231, de novo-1480) in first complete remission transplanted from 2010 to 2021, were included. Patients with de novo AML were younger, median age 55.8 versus 60.8 years, p < 0.0001, had better transplantation comorbidity index (HCT-CI) ≥ 3 21.3% versus 40.8%, p < 0.0001 and Karnofsky performance status (KPS) with KPS ≥ 90 in 78% versus 68.5%, respectively, p = 0.002. The two patient groups did not differ with respect to gender, cytomegalovirus serostatus, and cell source. Median time from diagnosis to HaploSCT was 5.2 versus 4.9 months, respectively, p = 0.005. Fewer sAML patients received myeloablative conditioning 35.1% versus 50.1%, p < 0.0001. Two hundred and eleven sAML and 410 de novo AML patients were included in the matched-pair analysis matching two de novo AML with each sAML. No significant difference was observed in any transplantation outcome parameter between the sAML versus de novo AML groups. Two-year non-relapse mortality and relapse incidence did not differ with HaploSCT for de novo versus sAML; 21.4% versus 21%, hazard ratio (HR) = 0.98, p = 0.9 and 23.4% versus 20.6%, HR = 0.92, p = 0.67, respectively. Two-year leukemia-free survival, overall survival, and graft-versus-host disease (GVHD)-free, relapse-free survival were also not different between the de novo AML and sAML groups 55.2% versus 58.4%, HR = 0.95, p = 0.67; 61.4% versus 66.4%, HR = 0.91, p = 0.51 and 46.3% versus 48.2%, HR = 0.92, p = 0.48, respectively. Similarly, the incidence of engraftment as well as acute and chronic GVHD was similar between the 2 cohorts. In conclusion, HaploSCT with PTCy may be able to overcome the bad prognosis of sAML as results are not significantly different to those of HaploSCT in de novo AML.

Thiotepa-busulfan-fludarabine Compared to Treosulfan-based Conditioning for Haploidentical Transplant With Posttransplant Cyclophosphamide in Patients With Acute Myeloid Leukemia in Remission: A Study From the Acute Leukemia Working Party of the EBMT.

We conducted a registry analysis including adult acute myeloid leukemia (AML) patients in remission who had received thiotepa, busulfan, and fludarabine (TBF) or treosulfan-based (Treo) conditioning for haplo-hematopoietic stem cell transplant (HSCT) with posttransplant cyclophosphamide (PTCy) between 2010 and 2020. A total of 1123 patients met the inclusion criteria (968 received TBF and 155 received Treo). A 1:1 matched-pair analysis was performed on 142 TBF and 142 Treo patients. In the Treo group, 68% of patients received treosulfan at a dose ≥36 g/m2 and 54% of patients received a second alkylator (thiotepa or melphalan). We observed a trend toward increased incidence of grade II-IV acute (a) graft-versus-host disease (GVHD) at 180 days in the TBF group compared with Treo (29% versus 20%; P = 0.08), while incidence of grade III-IV aGVHD was not statistically different. Similarly, the incidence of chronic (c) GVHD was not statistically different in the 2 groups. Incidence of nonrelapse mortality at 2 years was 19% in TBF and 14% in Treo (P = 0.4). Relapse incidence at 2 years was not statistically different in the 2 groups (16% and 18% in TBF and Treo, respectively; P = 0.9). Leukemia-free survival, overall survival, and GVHD-free, relapse-free survival was 65% versus 68% (P = 0.6), 73% versus 76% (P = 0.5), and 54% versus 53% (P = 0.8) in TBF versus Treo, respectively. In conclusion, we did not find a significant difference between the 2 conditioning in the present study; Treo and TBF represent 2 valid alternative regimens for haplo-HSCT with PTCy for AML in remission.

EBMT risk score predicts outcome of allogeneic hematopoietic stem cell transplantation in patients who have failed a previous transplantation procedure.

Increasing numbers of allogeneic hematopoietic stem cell transplantation (allo-SCT) are being performed for patients who have failed a previous allogeneic or autologous SCT. We investigated whether the EBMT risk score could predict outcome after a subsequent allo-SCT. We analyzed prognostic factors in 124 consecutive patients who underwent a second transplantation using an allogeneic donor at our institution. Patients with either a first autologous (N = 64) or first allogeneic (N = 60) SCT were included. Age, disease stage, time interval from diagnosis to transplantation, donor type, and donor-recipient sex combination were used to establish a score from 0 to 7 points, from which 3 groups were identified. The 5-year survival probability decreased from 51.7% for risk scores 0-3 (low, n = 25), to 29.3% for risk score 4 (intermediate, n = 42), and only 10.4% for risk scores 5-7 (high, n = 57), P = .001. We propose that the EBMT risk score can identify patients most likely to benefit from a second transplantation.

Optimizing patient selection for myeloablative allogeneic hematopoietic cell transplantation in chronic myeloid leukemia in chronic phase.

Outstanding results have been obtained in the treatment of chronic myeloid leukemia (CML) with first-line imatinib therapy. However, approximately 35% of patients will not obtain long-term benefit with this approach. Allogeneic hematopoietic stem cell transplantation (HCT) is a valuable second- and third-line therapy for appropriately selected patients. To identify useful prognostic indicators of transplantation outcome in postimatinib therapeutic interventions, we investigated the role of the HCT comorbidity index (HCT-CI) together with levels of C-reactive protein (CRP) before HCT in 271 patients who underwent myeloablative HCT for CML in first chronic phase. Multivariate analysis showed both an HCT-CI score higher than 0 and CRP levels higher than 9 mg/L independently predict inferior survival and increased nonrelapse mortality at 100 days after HCT. CML patients without comorbidities (HCT-CI score 0) with normal CRP levels (0-9 mg/L) may therefore be candidates for early allogeneic HCT after failing imatinib.

Third primary SARS-CoV-2 mRNA vaccines enhance antibody responses in most patients with haematological malignancies.

SARS-CoV-2 infection, and resulting disease, COVID-19, has a high mortality amongst patients with haematological malignancies. Global vaccine rollouts have reduced hospitalisations and deaths, but vaccine efficacy in patients with haematological malignancies is known to be reduced. The UK-strategy offered a third, mRNA-based, vaccine as an extension to the primary course in these patients. The MARCH database is a retrospective observational study of serological responses in patients with blood disorders. Here we present data on 381 patients with haematological malignancies. By comparison with healthy controls, we report suboptimal responses following two primary vaccines, with significantly enhanced responses following the third primary dose. These responses however are heterogeneous and determined by haematological malignancy sub-type and therapy. We identify a group of patients with continued suboptimal vaccine responses who may benefit from additional doses, prophylactic extended half-life neutralising monoclonal therapies (nMAB) or prompt nMAB treatment in the event of SARS-CoV-2 infection.

Reduced intensity versus non-myeloablative conditioning regimen for haploidentical transplantation and post-transplantation cyclophosphamide in complete remission acute myeloid leukemia: a study from the ALWP of the EBMT.

The optimal conditioning regimen prior haploidentical stem cell transplantation (Haplo-SCT) with post transplantation cyclophosphamide (PT-Cy) for acute myeloid leukemia (AML) remains unknown. A non-myeloablative conditioning (NMAC) regimen (cyclophosphamide + fludarabine + TBI 2 Gy [CyFluTBI]) is a safe approach, but relapse incidence remains high in this setting. Alternatively, a reduced intensity conditioning (RIC) regimen combining thiotepa and reduced-dose busulfan with fludarabine (TBF) may decrease AML relapse. However, an excess of toxicity may counterbalance this potential benefit. We retrospectively compared CyFluTBI vs. TBF in CR AML patients who underwent Haplo-SCT with PT-Cy, in two different populations based on age. We analyzed 490 patients. In patients aged <60 years (n = 203), we observed a higher RI (HR = 3.59, 95% CI = 1.75-7.37, p < 0.01), lower LFS (HR = 1.98, 95% CI = 1.22-3.22, p < 0.01) and lower OS (HR = 1.73, 95% CI = 1.04-2.88, p = 0.04) in the CyFluTBI group, without significant difference in NRM. In older patients (n = 287), we observed that conditioning regimen did not significantly influence LFS (HR = 0.90, 95% CI = 0.56-1.44, p = 0.65), OS (HR = 0.81, 95% CI = 0.49-1.32, p = 0.39) and RI (HR = 1.78, 95% CI = 0.90-3.50, p = 0.10), but showed that CyFluTBI was associated with a significantly lower risk of NRM (HR = 0.48, 95% CI = 0.25-0.92, p = 0.03). Thus, younger patients seem to benefit from conditioning intensification from CyFluTBI to TBF regimens prior PT-Cy Haplo-SCT for CR AML, while older ones do not.