Molecular MRD is strongly prognostic in patients with NPM1-mutated AML receiving venetoclax-based nonintensive therapy.

ABSTRACT: Assessment of measurable residual disease (MRD) by quantitative reverse transcription polymerase chain reaction is strongly prognostic in patients with NPM1-mutated acute myeloid leukemia (AML) treated with intensive chemotherapy; however, there are no data regarding its utility in venetoclax-based nonintensive therapy, despite high efficacy in this genotype. We analyzed the prognostic impact of NPM1 MRD in an international real-world cohort of 76 previously untreated patients with NPM1-mutated AML who achieved complete remission (CR)/CR with incomplete hematological recovery following treatment with venetoclax and hypomethylating agents (HMAs) or low-dose cytarabine (LDAC). A total of 44 patients (58%) achieved bone marrow (BM) MRD negativity, and a further 14 (18%) achieved a reduction of ≥4 log10 from baseline as their best response, with no difference between HMAs and LDAC. The cumulative rates of BM MRD negativity by the end of cycles 2, 4, and 6 were 25%, 47%, and 50%, respectively. Patients achieving BM MRD negativity by the end of cycle 4 had 2-year overall of 84% compared with 46% if MRD was positive. On multivariable analyses, MRD negativity was the strongest prognostic factor. A total of 22 patients electively stopped therapy in BM MRD-negative remission after a median of 8 cycles, with 2-year treatment-free remission of 88%. In patients with NPM1-mutated AML attaining remission with venetoclax combination therapies, NPM1 MRD provides valuable prognostic information.

Myeloablative Dose of Busulfan and Fludarabine Combined with In Vivo T Cell Depletion Is Safe and Effective Conditioning for Acute Myeloid Leukemia and Myelodysplastic Syndrome Patients.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative strategy for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). The prediction of transplantation-related mortality (TRM) using the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) score and an arbitrary upper age limit of 55 years for administering myeloablative conditioning (MAC) are common strategies to ensure a safe procedure. The use of reduced-toxicity conditioning regimens is an additional approach to providing safe and effective myeloablation. Herein we report the outcome of AML and MDS patients conditioned with fludarabine and a myeloablative dose of busulfan (FB4) stratified by age and HCT-CI score. The primary objective was overall survival (OS) for patients age ≥55 years. Secondary objectives were total OS, TRM, graft-versus-host disease (GVHD), and GVHD, relapse-free survival (GRFS). The 2 year OS was 72% in patients age <55 and 51% in patients age ≥55. In patients age ≥55 with an HCT-CI <2, the estimated 2 year OS was 64%, with median OS not reached. In those with HCT-CI ≥2, the 2-year OS was 43%, with a median OS of 14 months. The total cumulative incidence of relapse was 30% regardless of age or HCT-CI score. FB4 conditioning regimen offers a high rate of prolonged remission with a relapse rate similar to that reported in previous studies. These positive outcomes suggest that this conditioning platform can be offered to patients age ≥55 years in the absence of comorbidities, and that age should not be the sole determinant of conditioning intensity.

FLT3 inhibitors as MRD-guided salvage treatment for molecular failure in FLT3 mutated AML.

Patients with FLT3-mutated AML have a high relapse rate and suboptimal outcomes. Many have co-mutations suitable for measurable residual disease (MRD) monitoring by RT-qPCR and those destined to relapse can be identified by high or rising levels of MRD, called molecular failure.  This provides a window for pre-emptive intervention, but there is little evidence to guide treatment. The use of FLT3 inhibitors (FLT3i) appears attractive but their use has not yet been evaluated.  We identified 56 patients treated with FLT3i at molecular failure.  The FLT3 mutation was an ITD in 52, TKD in 7 and both in 3. Over half of patients had previously received midostaurin. Molecular failure occurred at a median 9.2 months from diagnosis and was treated with gilteritinib (n = 38), quizartinib (n = 7) or sorafenib (n = 11). 60% achieved a molecular response, with 45% reaching MRD negativity. Haematological toxicity was low, and 22 patients were bridged directly to allogeneic transplant with another 6 to donor lymphocyte infusion. 2-year overall survival was 80% (95%CI 69-93) and molecular event-free survival 56% (95%CI 44-72). High-sensitivity next-generation sequencing for FLT3-ITD at molecular failure identified patients more likely to benefit. FLT3i monotherapy for molecular failure is a promising strategy which merits evaluation in prospective studies.

Fludarabine-Melphalan-Campath, Followed by Unmanipulated Peripheral-Blood Haematopoietic Stem Cells, Can Still Cure Lymphoma.

Background: The second decade of this millennium was characterized by a widespread availability of chimeric antigen receptor T-cell (CAR-T) therapies to treat relapsed and refractory lymphomas. As expected, the role and indication of allogeneic haematopoietic stem cell transplant (allo-HSCT) in the management of lymphoma changed. Currently, a non-neglectable proportion of patients will be considered candidate for an allo-HSCT, and the debate of which transplant platform should be offered is still active. Objectives: to report the outcome of patients affected with relapsed/refractory lymphoma and transplanted following reduced intensity conditioning at King's College Hospital, London, between January 2009 and April 2021. Methods: Conditioning was with 150mg/m2 of fludarabine and melphalan of 140mg/m2. The graft was unmanipulated G-CSF mobilized peripheral blood haematopoietic stem cells (PBSC). Graft-versus-host disease (GVHD) prophylaxis consisted of pre-transplant Campath at the total dose of 60 mg in unrelated donors and 30 mg in fully matched sibling donors and ciclosporin. Results: One-year and five years OS were 87% and 79.9%, respectively, and median OS was not reached. The cumulative incidence of relapse was 16%. The incidence of acute GVHD was 48% (only grade I/II); no cases of grade III/IV were diagnosed. Chronic GVHD occurred in 39% of patients. TRM was 12%, with no cases developed within day 100 and 18 months after the procedure. Conclusions: The outcomes of heavily pretreated lymphoma patients are favorable, with median OS and survival not reached after a median of 49 months. In conclusion, even if some lymphoma subgroups cannot be treated (yet) with advanced cellular therapies, this study confirms the role of allo-HSCT as a safe and curative strategy.

Defective T-cell response to COVID-19 vaccination in acute myeloid leukaemia and myelodysplastic syndromes.

Limited data exist on COVID-19 vaccination efficacy in patients with acute myeloid leukemia and myelodysplasia with excess blasts (AML/MDS-EB2). We report results from a prospective study, PACE (Patients with AML and COVID-19 Epidemiology). 93 patients provided samples post-vaccine 2 or 3 (PV2, PV3). Antibodies against SARS-COV-2 spike antigen were detectable in all samples. Neutralization of the omicron variant was poorer than ancestral variants but improved PV3. In contrast, adequate T-cell reactivity to SARS-COV-2 spike protein was seen in only 16/47 (34%) patients PV2 and 23/52 (44%) PV3. Using regression models, disease response (not in CR/Cri), and increasing age predicted poor T cell response.

Posttransplant MRD and T-cell chimerism status predict outcomes in patients who received allografts for AML/MDS.

Allogeneic stem-cell transplant allows for the delivery of curative graft-versus-leukemia (GVL) in patients with acute myeloid leukemia/myelodysplasia (AML/MDS). Surveillance of T-cell chimerism, measurable residual disease (MRD) and blast HLA-DR expression may inform whether GVL effectiveness is reduced. We report here the prognostic impact of these biomarkers in patients allografted for AML/MDS. One hundred eighty-seven patients from FIGARO, a randomized trial of reduced-intensity conditioning regimens in AML/MDS, were alive and relapse-free at the first MRD time-point and provided monitoring samples for flow cytometric MRD and T-cell chimerism, requested to month+12. Twenty-nine (15.5%) patients had at least 1 MRD-positive result posttransplant. MRD-positivity was associated with reduced overall survival (OS) (hazard ratio [HR], 2.18; P = .0028) as a time-varying Cox variable and remained significant irrespective of pretransplant MRD status in multivariate analyses (P < .001). Ninety-four patients had sequential MRD with T-cell chimerism results at months+3/+6. Patients with full donor T-cell chimerism (FDTC) had an improved OS as compared with patients with mixed donor T-cell chimerism (MDTC) (adjusted HR=0.4; P = .0019). In patients with MDTC (month+3 or +6), MRD-positivity was associated with a decreased 2-year OS (34.3%) vs MRD-negativity (71.4%) (P = .001). In contrast, in the group with FDTC, MRD was infrequent and did not affect the outcome. Among patients with posttransplant MRD-positivity, decreased HLA-DR expression on blasts significantly reduced OS, supporting this as a mechanism for GVL escape. In conclusion, posttransplant MRD is an important predictor of the outcome in patients allografted for AML/MDS and is most informative when combined with T-cell chimerism results, underlining the importance of a GVL effect in AML/MDS.

Germ line DDX41 mutations define a unique subtype of myeloid neoplasms.

Germ line DDX41 variants have been implicated in late-onset myeloid neoplasms (MNs). Despite an increasing number of publications, many important features of DDX41-mutated MNs remain to be elucidated. Here we performed a comprehensive characterization of DDX41-mutated MNs, enrolling a total of 346 patients with DDX41 pathogenic/likely-pathogenic (P/LP) germ line variants and/or somatic mutations from 9082 MN patients, together with 525 first-degree relatives of DDX41-mutated and wild-type (WT) patients. P/LP DDX41 germ line variants explained ∼80% of known germ line predisposition to MNs in adults. These risk variants were 10-fold more enriched in Japanese MN cases (n = 4461) compared with the general population of Japan (n = 20 238). This enrichment of DDX41 risk alleles was much more prominent in male than female (20.7 vs 5.0). P/LP DDX41 variants conferred a large risk of developing MNs, which was negligible until 40 years of age but rapidly increased to 49% by 90 years of age. Patients with myelodysplastic syndromes (MDS) along with a DDX41-mutation rapidly progressed to acute myeloid leukemia (AML), which was however, confined to those having truncating variants. Comutation patterns at diagnosis and at progression to AML were substantially different between DDX41-mutated and WT cases, in which none of the comutations affected clinical outcomes. Even TP53 mutations made no exceptions and their dismal effect, including multihit allelic status, on survival was almost completely mitigated by the presence of DDX41 mutations. Finally, outcomes were not affected by the conventional risk stratifications including the revised/molecular International Prognostic Scoring System. Our findings establish that MDS with DDX41-mutation defines a unique subtype of MNs that is distinct from other MNs.

Introducing biomarkers for invasive fungal disease in haemato-oncology patients: a single-centre experience.

Hypothesis/Gap Statement. The impacts of increased biomarker testing on antifungal prescribing have not yet been fully examined in a real-life setting.Objectives. Biomarkers for invasive fungal disease (IFD) have been shown to reduce antifungal prescriptions in neutropaenic haemato-oncology patients. Our study aimed to assess the real-life impacts of introducing a novel biomarker-based pathway, incorporating serum galactomannan and Aspergillus PCR, for pyrexial haemato-oncology admissions.Methods. Patients with neutropaenic fever were identified prospectively after introduction of the new pathway from 2013-2015. A historical group of neutropaenic patients who had blood cultures taken from 2009-2012 was generated for comparison. Clinical details, including demographics, underlying diagnosis, investigations, radiology and antimicrobial treatment were obtained.Results. Prospective data from 308 patients were compared to retrospective data from 302 patients. The proportion of patients prescribed an antifungal medication was unchanged by the pathway (P=0.79), but the pattern was different, with more patients receiving targeted antifungals (P=0.04). A negative serum galactomannan test was not sufficient evidence to withhold therapy, with 17.2% of these episodes felt to have possible or probable IFD using the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) criteria. There was no difference in 30-day mortality (P=0.21) or 1-year mortality (P=0.57) following introduction of the pathway.Conclusions. Biomarkers can be used safely as part of a multidisciplinary approach to the diagnosis of IFD in neutropaenic haemato-oncology patients. Whilst they do not necessarily result in antifungal therapy being withheld, they can allow more confident diagnosis of IFD and more specific antifungal therapy in selected cases.

Mixed T cell lineage chimerism in acute leukemia/MDS using pre-emptive donor lymphocyte infusion strategy-Is it prognostic?-a single-center retrospective study.

Pre-emptive DLI (pDLI) is an effective strategy in lowering the risk of relapse without significantly increasing the risk of graft-versus-host disease (GVHD) in the case of T cell lineage mixed chimerism (MC) post allogeneic transplant in hematological malignancies. Many patients, however, fail to receive timely pDLI and have dismal outcomes, which are not taken into consideration. We compared long-term outcomes of 106 patients having T cell MC after day 60 and undergoing allogeneic stem cell allograft for acute leukemia from an unrelated donor (UD), with 111 patients having complete chimerism (CC). Fifty-three (56%) patients received prophylactic pDLI. Thirty-six patients (67%) had a response (RR), 17 (33%) had no response (NR), and fifty-two (54%) did not receive any pDLI (ND). OS was better in MC group as compared to CC (54% vs 43%, p = 0.04), mainly due to reduction in NRM (14% vs 25%, p = 0.05), and all grade acute and chronic GVHD. Within the MC group, response to pDLI was the only significant factor predicting OS, DFS, and relapses with NR and ND having unfavorable outcomes as compared to RR (p = 0.001). T cell MC in patients undergoing UD allografts with alemtuzumab is no longer an adverse prognostic factor, as compared to patients having CC, after timely implementation of pDLI.

Unusual CD34 positivity in acute myeloid leukaemia with myelodysplasia-related changes with megakaryoblastic differentiation.

Acute megakaryoblastic leukaemia is a rare entity with distinct immunophenotype profile and cytogenetic lesions. Herein, we report a case of acute myeloid leukaemia with myelodysplastic-related changes with megakaryoblastic differentiation in absence of recurrent genomic lesions such as t(1;22), inv(3) and t(3;3). One of the peculiarities of this case is the positivity of CD34+ within the abnormal megakaryoblasts; CD61 immunohistochemistry highlights the heavily infiltration of bone marrow from abnormal megakaryoblasts.

Early and late-onset veno-occlusive disease/sinusoidal syndrome post allogeneic stem cell transplantation - a real-world UK experience.

Classical veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a serious complication post allogeneic hematopoietic stem cell transplantation (HSCT). Before the recently revised EBMT criteria, the Baltimore and modified Seattle criteria failed to recognize the syndrome of late-onset VOD. We present real-world experience from a large UK transplant center reporting on VOD/SOS in consecutive HSCT adult patients (n = 530), transplanted for hematological cancers. We identified 27 patients treated with Defibrotide for VOD/SOS diagnosis, where detailed data were available for final analysis. Using standard definitions including EBMT criteria, around 30% (n = 8/27) of cases classified as late-onset VOD presenting at median of 46 (22-93) days but with D100 survival (63% vs 58%, Log-rank; P = 0.81) comparable to classical VOD. Hazard ratio for D100 mortality was 2.82 (95% CI: 1.74-4.56, P < .001, Gray test) with all VOD/SOS events. Twenty percent (n = 2/8) of late-onset VOD patients were anicteric and 42% (n = 8) classical VOD patients presented with refractory thrombocytopenia, while less than half met EBMT criteria for classical VOD in adults, highlighting gaps in real-world diagnostic limitations using EBMT criteria. However, challenges remain about underrecognition and difficulties related to early defibrotide access for treatment of late-onset VOD in current treatment guidelines. Our report strongly supports early Defibrotide for the treatment of severe VOD/SOS in adults regardless of time of onset.

Molecular MRD status and outcome after transplantation in NPM1-mutated AML.

Relapse remains the most common cause of treatment failure for patients with acute myeloid leukemia (AML) who undergo allogeneic stem cell transplantation (alloSCT), and carries a grave prognosis. Multiple studies have identified the presence of measurable residual disease (MRD) assessed by flow cytometry before alloSCT as a strong predictor of relapse, but it is not clear how these findings apply to patients who test positive in molecular MRD assays, which have far greater sensitivity. We analyzed pretransplant blood and bone marrow samples by reverse-transcription polymerase chain reaction in 107 patients with NPM1-mutant AML enrolled in the UK National Cancer Research Institute AML17 study. After a median follow-up of 4.9 years, patients with negative, low (<200 copies per 105ABL in the peripheral blood and <1000 copies in the bone marrow aspirate), and high levels of MRD had an estimated 2-year overall survival (2y-OS) of 83%, 63%, and 13%, respectively (P < .0001). Focusing on patients with low-level MRD before alloSCT, those with FLT3 internal tandem duplications(ITDs) had significantly poorer outcome (hazard ratio [HR], 6.14; P = .01). Combining these variables was highly prognostic, dividing patients into 2 groups with 2y-OS of 17% and 82% (HR, 13.2; P < .0001). T-depletion was associated with significantly reduced survival both in the entire cohort (2y-OS, 56% vs 96%; HR, 3.24; P = .0005) and in MRD-positive patients (2y-OS, 34% vs 100%; HR, 3.78; P = .003), but there was no significant effect of either conditioning regimen or donor source on outcome. Registered at ISRCTN (http://www.isrctn.com/ISRCTN55675535).

Full donor chimerism without graft-versus-host disease: the key factor for maximum benefit of pre-emptive donor lymphocyte infusions (pDLI).

Compared to standard-conditioned regimens, reduced-intensity conditioning and T-cell depletion deliver lower transplant-related mortality and decreased graft-vs-host disease after allogeneic hematopoietic stem-cell transplantation. These advantages may however be mitigated by increased relapse rates and delays in achievement of full donor chimerism (FDC). Pre-emptive donor lymphocyte infusions (pDLI) facilitate the conversion of mixed (MDC) to FDC. However, there is a lack of published data on the risk/benefit analysis of this intervention. We performed a retrospective analysis of 119 patients who received 276 pDLI doses for falling CD3 chimerism, CD3 < 50% or mixed XX/XY karyotype. 71/119(60%) Patients achieved FDC, with only one reverting to MDC. Cumulative incidence (CI) of relapse at 5 years was significantly lower in the FDC group (16.0 vs 41.4%, p < 0.001). Those patients who achieved FDC had improved EFS (p < 0.001) and OS (p < 0.001). Interestingly, patients with FDC who developed DLI-induced graft-vs-host disease (GvHD) showed a similar outcome to those with MDC. The majority of patients who receive pDLI convert to FDC and retain that status. Achievement of FDC after pDLI impacts on survival, and those patients who achieve FDC without GvHD, experience maximum clinical benefit. Strategies to minimise DLI-induced GvHD should be considered to maximise the therapeutic potential of this intervention.

Characterization of innate immune viral sensors in patients following allogeneic hematopoietic stem cell transplantation.

Viral infection is a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplant (HSCT), with up to one in four deaths directly linked to viral disease. Whilst awaiting lymphocyte reconstitution post-HSCT, the innate antiviral immune response is the first line of defense against invading viruses. Several novel innate viral-sensing pathways have recently been characterized, but their physiological importance in humans is poorly understood. We analyzed a panel of innate viral-sensor genes in HSCT patients, and assessed whether differences in innate antiviral responses could account for variation in susceptibility to viral infections. Expression levels of innate viral sensors in HSCT patients with active viral infections, HSCT patients without active infections and healthy volunteers were highly homogenous. Although IFN-α expression was up-regulated in actively infected patients relative to controls, a corresponding up-regulation of innate viral sensor expression was not observed. IFN-α stimulation of patient PBMCs in vitro showed intact IFN-α signaling, but actively infected patients' PBMCs had reduced up-regulation of innate viral sensors. We show that the aberrant IFN-α responses in HSCT patients were not due to calcineurin inhibition. Our data therefore raises the possibility of an intrinsic defect in innate viral sensor up-regulation in HSCT patients following viral infection.

BCSH/BSBMT/UK clinical virology network guideline: diagnosis and management of common respiratory viral infections in patients undergoing treatment for haematological malignancies or stem cell transplantation.

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology, the British Society for Bone Marrow Transplantation and the UK Clinical Virology Network has reviewed the available literature and made recommendations for the diagnosis and management of respiratory viral infections in patients with haematological malignancies or those undergoing haematopoietic stem cell transplantation. This guideline includes recommendations for the diagnosis, prevention and treatment of respiratory viral infections in adults and children. The suggestions and recommendations are primarily intended for physicians practising in the United Kingdom.