Faculty Bibliography

PURPOSE/OBJECTIVE:The genetic basis of myelodysplastic syndromes (MDS) is heterogeneous, and various combinations of somatic mutations are associated with different clinical phenotypes and outcomes. Whether the genetic basis of MDS influences the outcome of allogeneic hematopoietic stem-cell transplantation (HSCT) is unclear. PATIENTS AND METHODS/METHODS:We studied 401 patients with MDS or acute myeloid leukemia (AML) evolving from MDS (MDS/AML). We used massively parallel sequencing to examine tumor samples collected before HSCT for somatic mutations in 34 recurrently mutated genes in myeloid neoplasms. We then analyzed the impact of mutations on the outcome of HSCT. RESULTS:Overall, 87% of patients carried one or more oncogenic mutations. Somatic mutations of ASXL1, RUNX1, and TP53 were independent predictors of relapse and overall survival after HSCT in both patients with MDS and patients with MDS/AML (P values ranging from .003 to .035). In patients with MDS/AML, gene ontology (ie, secondary-type AML carrying mutations in genes of RNA splicing machinery, TP53-mutated AML, or de novo AML) was an independent predictor of posttransplantation outcome (P = .013). The impact of ASXL1, RUNX1, and TP53 mutations on posttransplantation survival was independent of the revised International Prognostic Scoring System (IPSS-R). Combining somatic mutations and IPSS-R risk improved the ability to stratify patients by capturing more prognostic information at an individual level. Accounting for various combinations of IPSS-R risk and somatic mutations, the 5-year probability of survival after HSCT ranged from 0% to 73%. CONCLUSION/CONCLUSIONS:Somatic mutation in ASXL1, RUNX1, or TP53 is independently associated with unfavorable outcomes and shorter survival after allogeneic HSCT for patients with MDS and MDS/AML. Accounting for these genetic lesions may improve the prognostication precision in clinical practice and in designing clinical trials.

Patients with acute myeloid leukemia (AML) during induction chemotherapy and those who receive allogeneic hematopoietic stem cell transplantation (HSCT) are at higher risk of invasive fungal infections (IFI). In the present study, we investigated whether the risk of IFI in AML patients receiving HSCT might be affected by the antifungal prophylaxis with posaconazole administered during the induction/salvage chemotherapy treatment. Between August 2001 and April 2015, 130 patients with AML received itraconazole/fluconazole (group A) and 99 received posaconazole (group B) as antifungal prophylaxis after induction/salvage chemotherapy at 7 Italian centers and all patients received fluconazole as antifungal prophylaxis after HSCT. The median duration of antifungal prophylaxis after induction/salvage chemotherapy was significantly longer for patients in group A than for those in group B (24 days versus 20 days, P = .019). The 1-year cumulative incidence of proven/probable IFI after HSCT was 14% and 4% in group A and group B, respectively (P = .012). Fungal-free survival and overall survival at 1 year after HSCT were 66% and 70% in group A, and 75% and 77% in group B (P = .139 and P = .302), respectively. Multivariate logistic analysis identified the use of alternative donors (matched unrelated donor: odds ratio [OR], 3.25; haploidentical/partially matched related donor: OR, 3.19), antifungal prophylaxis with itraconazole/fluconazole (OR, 3.82), and reduced-intensity conditioning (OR, 4.92) as independent risk factors for the development of IFI after HSCT. In summary, the present study suggests that the protective effects of posaconazole during induction/salvage chemotherapy for AML patients may have long-lasting benefits and eventually contribute to reduce the risk of IFI when patients undergo allogeneic HSCT.

BACKGROUND:Allogeneic hematopoietic stem cell transplantation (HSCT) is potentially curative in a variety of hematological malignancies. Graft-vs.-host disease (GvHD) remains a life-threatening complication. Standard treatment is high-dose (HD) corticosteroids. Steroid-refractory (SR) GvHD is associated with poor prognosis. At present, second-line treatment is ill-defined and includes a number of agents. Novel insights into the pathophysiology of acute GvHD (aGvHD) highlight the relevant role of the host inflammatory response governed by several kinase families, including Janus kinases (JAK)1/2. Ruxolitinib, a JAK1/2 inhibitor approved for intermediate-2/high-risk myelofibrosis, was recently employed in SR-GvHD with encouraging overall response rates. Clinical experience however remains limited. CASE PRESENTATION:A 51-year-old male with refractory anemia with excess blast type-2 underwent a myeloablative allogeneic HSCT from a 9/10 HLA-matched unrelated donor after conditioning with busulfan and cyclophosphamide. GvHD prophylaxis consisted of cyclosporine, methotrexate, and thymoglobulin. CD34(+) cells/kg infused were 8.69 × 10(6) kg. On day 29, the patient developed overall grade IV aGvHD with biopsy proven stage IV gastrointestinal (GI) GvHD refractory to HD corticosteroids. Patient conditions rapidly deteriorated and became critical despite the addition of mycophenolate mofetil and budesonide. On day 33, Ruxolitinib was started, and on day 39 the patient clinical conditions gradually improved. Complete resolution of aGvHD was also confirmed by histology on day 54. CONCLUSIONS:At 5 months from HSCT, the patient is well and in continuous hematological complete remission without flare of GvHD. Ruxolitinib was discontinued on day 156. Ruxolitinib is feasible and effective in SR-aGvHD though large prospective clinical trials are warranted.

Immunophenotypic remission (IR) is a strong prognostic factor in myeloma patients. The combination of IR and conventional CR was retrospectively evaluated in 66 patients after allografting. IR was defined as the absence of monoclonal plasma cells in BM aspirates by multiparameter flow cytometry. Conditioning was non-myeloablative in 55 patients; reduced-intensity in 10 and myeloablative in 1 patient. The allograft was given upfront in 35/66 (53%) patients. After a median follow-up of 7.1 years, 24 patients achieved both CR and IR (CR/IR group), 21 achieved IR but not CR with persistence of a urine/serum M-component (no CR/IR group) and 21 did not achieve either CR or IR (no CR/no IR group). Median OS and EFS were 'not reached' and 59 months in the CR/IR group; 64 and 16 months in the no CR/IR; and 36 and 6 months in the no CR/no IR, respectively (P<0.001). Cumulative incidence of extramedullary disease was 4.4% in the CR/IR, 38.1% in the no CR/IR and 14.3% in the no CR/no IR groups, respectively, at 4 years (P<0.001). IR was a valid tool to monitor residual disease after allografting, and allowed definition of a cohort of patients at higher incidence of extramedullary relapse.

Several studies provided evidence of a consistent antileukemic effect induced by cytomegalovirus (CMV) replication in acute myeloid leukemia (AML) patients receiving allogeneic hematopoietic stem cell transplantation (HSCT), however the use of antithymocyte globulin (ATG) as graft-versus-host disease prophylaxis, may potentially abrogate the protective effect of CMV infection. To address this issue, we retrospectively analyzed the risk of relapse in a cohort of 101 patients with AML who received grafts from an unrelated donor after a conditioning regimen including ATG. The cumulative incidence of CMV reactivation, evaluated by RT qPCR, was 59% at 12 months, and 93% of CMV reactivations occurred within the first 100 days post HSCT. The 5-year cumulative incidence of relapse in patients with CMV reactivation was 29% compared with 37% for patients without CMV reactivation, and the only factor associated with a reduced 5-year cumulative incidence of relapse was the disease status at HSCT (P < 0.001). In the multivariable model adverse cytogenetics (HR 2.42, 95% CI 1.02-5.72; P = 0.044) and acute GVHD (HR 3.36, 95% CI 1.32-8.54; P =  0.011) were independent risk factors for reducing overall survival (OS), while the presence of chronic GVHD was associated with a better OS (HR 0.37, 95% CI 0.15-0.89; P = 0.027). CMV replication was not an independent risk factor for OS (HR 1.06, 95% CI 0.07-15.75; P = 0.965). In Conclusion, the results of present study suggest that relapse prevention in patients with AML receiving T-cell depleted HSCT using ATG do not benefit from CMV reactivation.

BACKGROUND:The standard busulfan-cyclophosphamide myeloablative conditioning regimen is associated with substantial non-relapse mortality in patients older than 40 years with acute myeloid leukaemia who are undergoing allogeneic stem-cell transplantation. Because the combination of busulfan plus fludarabine has been proposed to reduce non-relapse mortality, we aimed to compare this treatment with busulfan plus cyclophosphamide as a preparative regimen in these patients. METHODS:We did an open-label, multicentre, randomised, phase 3 trial for patients with acute myeloid leukaemia at 25 hospital transplant centres in Italy and one in Israel. Eligible patients were aged 40-65 years, had an Eastern Cooperative Oncology Group performance status less than 3, and were in complete remission. Patients were randomly assigned 1:1 to receive intravenous busulfan plus cyclophosphamide or busulfan plus fludarabine. Treatment allocations were not masked to investigators or patients. Randomisation was done centrally via a dedicated web-based system using remote data entry, with patients stratified by donor type and complete remission status. Patients allocated to busulfan plus cyclophosphamide received intravenous busulfan 0·8 mg/kg four times per day during 2 h infusions for four consecutive days (16 doses from days -9 through -6; total dose 12·8 mg/kg) and cyclophosphamide at 60 mg/kg per day for two consecutive days (on days -4 and -3; total dose 120 mg/kg). Patients allocated to busulfan plus fludarabine received the same dose of intravenous busulfan (from days -6 through -3) and fludarabine at 40 mg/m(2) per day for four consecutive days (from days -6 through -3; total dose 160 mg/m(2)). The primary endpoint was 1-year non-relapse mortality, which was assessed on an intention-to-treat basis; safety outcomes were assessed in the per-protocol population. This trial has been completed and is registered with ClinicalTrials.gov, number NCT01191957. FINDINGS/RESULTS:Between Jan 3, 2008, and Dec 20, 2012, we enrolled and randomly assigned 252 patients to receive busulfan plus cyclophosphamide (n=125) or busulfan plus fludarabine (n=127). Median follow-up was 27·5 months (IQR 9·8-44·3). 1-year non-relapse mortality was 17·2% (95% CI 11·6-25·4) in the busulfan plus cyclophosphamide group and 7·9% (4·3-14·3) in the busulfan plus fludarabine group (Gray's test p=0·026). The most frequently reported grade 3 or higher adverse events were gastrointestinal events (28 [23%] of 121 patients in the busulfan plus cyclophosphamide group and 26 [21%] of 124 patients in the busulfan plus fludarabine group) and infections (21 [17%] patients in the busulfan plus cyclophosphamide group and 13 [10%] patients in the busulfan plus fludarabine group had at least one such event). INTERPRETATION/CONCLUSIONS:In older patients with acute myeloid leukaemia, the myeloablative busulfan plus fludarabine conditioning regimen is associated with lower transplant-related mortality than busulfan plus cyclophosphamide, but retains potent antileukaemic activity. Accordingly, this regimen should be regarded as standard of care during the planning of allogeneic transplants for such patients. FUNDING/BACKGROUND:Agenzia Italiana del Farmaco.

Early T-cell reconstitution following allogeneic transplantation depends on the persistence and function of T cells that are adoptively transferred with the graft. Posttransplant cyclophosphamide (pt-Cy) effectively prevents alloreactive responses from unmanipulated grafts, but its effect on subsequent immune reconstitution remains undetermined. Here, we show that T memory stem cells (TSCM), which demonstrated superior reconstitution capacity in preclinical models, are the most abundant circulating T-cell population in the early days following haploidentical transplantation combined with pt-Cy and precede the expansion of effector cells. Transferred naive, but not TSCM or conventional memory cells preferentially survive cyclophosphamide, thus suggesting that posttransplant TSCM originate from naive precursors. Moreover, donor naive T cells specific for exogenous and self/tumor antigens persist in the host and contribute to peripheral reconstitution by differentiating into effectors. Similarly, pathogen-specific memory T cells generate detectable recall responses, but only in the presence of the cognate antigen. We thus define the cellular basis of T-cell reconstitution following pt-Cy at the antigen-specific level and propose to explore naive-derived TSCM in the clinical setting to overcome immunodeficiency. These trials were registered at www.clinicaltrials.gov as #NCT02049424 and #NCT02049580.

Robust T cell function recovery has been shown to be crucial in determining allogeneic hematopoietic stem cell transplantation (HSCT) outcome, and there is growing evidence that the thymus plays a central role in regulating this process. We performed a long-term analysis of the role of thymic activity recovery in a population of pediatric patients undergoing allogeneic HSCT by signal joint T cell receptor excision circle (sjTREC) quantification. In this study, characterized by a long-term follow-up (median, 72 months), we found patients with higher levels of sjTRECs before transplantation had a statistically significant reduced risk of death compared with patients with lower values (relative risk, .31; 95% confidence interval, .30 to .32; P = .02), showing this different outcome was mainly related to a reduction of relapse incidence (14% versus 43%, P = .02). Unlike previous reports, we observed no correlation between sjTREC levels and lymphocyte recovery. Moreover, we confirmed that only graft-versus-host disease influenced thymic activity after transplantation. In conclusion, our results suggest an association between pretransplantation thymic activity and the long-term outcome of pediatric patients undergoing HSCT, mainly through a reduction of relapse opportunities.