Nicoletta Colombo

Leukaemia relapse after allogeneic transplants for acute myeloid leukaemia: predictive role of WT1 expression

We assessed WT1 expression (expressed as messenger copies/104 ABL1) from marrow cells of 122 patients with acute myeloid leukaemia (AML), before and after an unmanipulated allogeneic haemopoietic stem cell transplant (HSCT). The median age was 44 years (15–69), 59% were in first remission, 74% received a myeloablative conditioning regimen and the median follow up was 865 d (34–2833). Relapse was higher in 67 patients with WT1 expression, at any time post‐HSCT, exceeding 100 copies (54%), as compared to 16%, for 55 patients with post‐HSCT WT1 expression <100 copies (P < 0·0001). Similarly, actuarial 5‐year survival (OS) was 40% vs. 63%, respectively (P = 0·03). In multivariate Cox analysis, WT1 expression post‐HSCT was the strongest predictor of relapse (Hazard Ratio [HR] 4·5, P = 0·0001), independent of disease phase (HR 2·3, P = 0·002). Donor lymphocyte infusions (DLI) were given to 17 patients because of increasing WT1 levels: their OS was 44%, vs. 14% for 21 patients with increasing WT1 expression who did not receive DLI (P = 0·004). In conclusion, WT1 expression post‐HSCT is a strong predictor of leukaemia relapse and survival in AML; WT1 may be used as a marker for early interventional therapy.

DLI after haploidentical BMT with post-transplant CY

Forty-two patients relapsing after an unmanipulated haploidentical BM transplant and post-transplant CY (PT-CY), were given 108 DLI, with median interval from transplant of 266 days (range, 67–1372). DLI were given at escalating doses, expressed as CD3+ cells/kg, without GVHD prophylaxis, and ranged from 1 × 103 to 1 × 107 cells/kg (median 5 × 105 cells/kg). The average number of DLI per patient was 2.6 (range, 1–6). The diagnosis was leukemias (n=32) grafted with a myeloablative regimen and Hodgkin’s disease (n=10), grafted with a nonmyeloablative regimen. Leukemic patients with molecular relapse (n=20), received DLI alone (n=17) or in association with azacytidine (n=3); leukemic patients with hematologic relapse (n=12) received chemotherapy followed by DLI (n=11) or DLI alone (n=1); Hodgkin patients received DLI following 1–3 courses of chemotherapy. In these three groups the incidence of acute GVHD II–III was 15%, 17% and 10%; response rate was 45%, 33% and 70%; 2-year actuarial survival was 43%, 19% and 80% respectively. This study confirms that escalating doses of DLI can be given in the haploidentical setting with PT-CY, with a relatively low risk of acute GVHD. Response rates and survival are dependent on the underlying disease.

WT1 overexpression at diagnosis may predict favorable outcome in patients with de novo non-M3 acute myeloid leukemia

Abstract We reviewed the frequency and prognostic significance of FLT3 (fms-like tyrosine kinase receptor-3) and NPM (nucleophosmin) gene mutations and WT1 (Wilms’ tumor) and BAALC (brain and acute leukemia, cytoplasmic) gene expression in 100 consecutive patients with intermediate and poor cytogenetic risk de novo acute myeloid leukemia (AML) receiving conventional anthracycline–AraC based therapy. We observed a strict relationship between unfavorable karyotype and BAALC >1000 (p = 0.0001). Multivariate analysis of 81 patients with intermediate karyotype revealed that younger age (p = 0.00009), NPM gene mutation (p = 0.002), and WT1 >75th percentile (>2365) (p = 0.003) were independent, positive factors for complete remission (CR). WT1 expression above 2365 was correlated also to longer event-free survival (EFS) and overall survival (OS) in the same subset of patients (p = 0.003 and p = 0.02, respectively); the same finding occurred in younger patients with AML with intermediate karyotype (p = 0.008 and p = 0.01, respectively). In patients with intermediate karyotype, FLT3 internal tandem duplication (ITD) negatively affected EFS (EFS at 30 months: 30% vs. 6% in FLT3-ITD negative and FLT3 positive patients, respectively; p = 0.01) and OS (OS at 30 months: 38% vs. 20%, p = 0.03). The positive prognostic value of high WT1 expression does not have a clear explanation; it may be implicated either with WT1 anti-oncogenic function, or with the stimulating effect of WT1 oncogene on the leukemic cellular cycle, possibly associated with an enhanced response to chemotherapy.

Integrating post induction WT1 quantification and flow-cytometry results improves minimal residual disease stratification in acute myeloid leukemia

Fifty uniformly treated adult AML patients were analyzed with respect to pre-treatment and post-induction risk factors. Forty-two patients achieving complete hematological remission were assessed for minimal residual disease (MRD) by WT1 gene expression; 34 by flow-cytometry (flow-MRD). Patients who were flow-MRD negative had a better 3-year disease-free (DFS; 79.5% vs. 27.3%; p=.032) compared with patients who were still positive after induction. Interestingly, DFS of flow-MRD positive patients was not related to the amount of flow-detected clone population (≥ or <1%, p=.41) but to WT1 reduction (ΔWT1, 3-year DFS; 46.2% vs. 0% if ΔWT1 was ≥ or < of 1.5 log, p=.001). In AML, combining MRD results provided by WT1 quantification and flow-cytometry improves the reliability of MRD-based prognostic stratification. Similar analyses by further larger studies should be advocated.

High feasibility and antileukemic efficacy of fludarabine, cytarabine, and idarubicin (FLAI) induction followed by risk-oriented consolidation: A critical review of a 10-year, single-center experience in younger, non M3 AML patients.

About 105 consecutive acute myeloid leukemia (AML) patients treated with the same induction‐consolidation program between 2004 and 2013 were retrospectively analyzed. Median age was 47 years. The first induction course included fludarabine (Flu) and high‐dose cytarabine (Ara‐C) plus idarubicin (Ida), with or without gemtuzumab‐ozogamicin (GO) 3 mg/m2 (FLAI‐5). Patients achieving complete remission (CR) received a second course without fludarabine but with higher dose of idarubicin. Patients not achieving CR received an intensified second course. Patients not scheduled for early allogeneic bone marrow transplantation (HSCT) where planned to receive at least two courses of consolidation therapy with Ara‐C. Our double induction strategy significantly differs from described fludarabine‐containing regimens, as patients achieving CR receive a second course without fludarabine, to avoid excess toxicity, and Ara‐C consolidation is administrated at the reduced cumulative dose of 8 g/m2 per cycle. Toxicity is a major concern in fludarabine containing induction, including the recent Medical Research Council AML15 fludarabine, cytarabine, idaraubicin and G‐CSF (FLAG‐Ida) arm, and, despite higher anti‐leukemic efficacy, only a minority of patients is able to complete the full planned program. In this article, we show that our therapeutic program is generally well tolerated, as most patients were able to receive subsequent therapy at full dose and in a timely manner, with a 30‐day mortality of 4.8%. The omission of fludarabine in the second course did not reduce efficacy, as a CR rate of 83% was achieved and 3‐year disease‐free survival and overall survival (OS) were 49.6% and 50.9%, respectively. Our experience shows that FLAI‐5/Ara‐C + Ida double induction followed by risk‐oriented consolidation therapy can result in good overall outcome with acceptable toxicity. Am. J. Hematol. 91:755–762, 2016.

Combining flow cytometry and WT1 assessment improves the prognostic value of pre-transplant minimal residual disease in acute myeloid leukemia

There is increasing evidence that evaluating minimal residual disease (MRD) at various time points during acute myeloid leukemia (AML) therapy retains a strong prognostic value.[1][1]–[3][2] In particular, the persistence of MRD positivity before hematopoietic stem cell transplantation (HSCT) has

Evaluating Treatment Response of Chronic Myeloid Leukemia: Emerging Science and Technology

Chronic myeloid leukemia (CML) is a hematological disease accounting for about 15-20% of all adult leukemias. The clinical and biologic advances achieved in such a malignancy, represent one of the best successes obtained by translational medicine. Indeed, identification of the fusion oncogene BCR-ABL has allowed using of small molecule inhibitors of its tyrosine kinase activity which, in turn, have literally revolutionized the treatment of CML. Importantly the successfully clinical management was also realized on appropriate diagnosis, disease monitoring as well as early identification of such mutations causing drug resistance. Notably the recent availability of refined laboratory equipments represented by the Next Generation Sequencing (NGS) and genomic analyses has further contributed to gain ground towards the cure of this tumor. These issues are discussed here together with an overview on how patients treated with tyrosine kinase inhibitors should be monitored.

Nucleophosmin gene-based monitoring in de novo cytogenetically normal acute myeloid leukemia with nucleophosmin gene mutations: comparison with cytofluorimetric analysis and study of Wilms tumor gene 1 expression

Abstract We compared the clinical value of minimal residual disease (MRD) monitoring by cytofluorimetric methods, Wilms tumor gene 1 (WT1) expression and the study of nucleophosmin gene (NPM) mutations in a series of 26 patients with NPM-mutated de novo acute myeloid leukemia (NPM-AML) who achieved complete hematological remission after conventional chemotherapy. The relapse risk was significantly lower only in patients achieving a NPM molecular complete response (NPM mol-CR) and confirmed NPM mol-CR (non-detectable NPM mutations in two consecutive marrow samples). The disease-free survival (DFS) of patients achieving a < 4-log or ≥ 4-log reduction in NPM value after induction therapy was 12.6 % and 50%, respectively, at 36 months (p = 0.009). The attainment of a confirmed NPM-CR had a significant influence on overall survival (OS at 36 months was 64.3% and 11.9% in patients obtaining or not obtaining confirmed NPM-CR, respectively, p < 0.03). We confirm that NPM-molecular relapse (NPM-rel) is always followed by hematological relapse (H-rel), but longitudinal studies of NPM mutations may predict an impending H-rel earlier than flow cytometric- or WT1-based methods.

Depletion of SIRT6 enzymatic activity increases acute myeloid leukemia cells vulnerability to DNA-damaging agents

Genomic instability plays a pathological role in various malignancies, including acute myeloid leukemia (AML), and thus represents a potential therapeutic target. Recent studies demonstrate that SIRT6, a NAD+-dependent nuclear deacetylase, functions as genome-guardian by preserving DNA integrity in different tumor cells. Here, we demonstrate that also CD34+ blasts from AML patients show ongoing DNA damage and SIRT6 overexpression. Indeed, we identified a poor-prognostic subset of patients, with widespread instability, which relies on SIRT6 to compensate for DNA-replication stress. As a result, SIRT6 depletion compromises the ability of leukemia cells to repair DNA double-strand breaks that, in turn, increases their sensitivity to daunorubicin and Ara-C, both in vitro and in vivo. In contrast, low SIRT6 levels observed in normal CD34+ hematopoietic progenitors explain their weaker sensitivity to genotoxic stress. Intriguingly, we have identified DNA-PKcs and CtIP deacetylation as crucial for SIRT6-mediated DNA repair. Together, our data suggest that inactivation of SIRT6 in leukemia cells leads to disruption of DNA-repair mechanisms, genomic instability and aggressive AML. This synthetic lethal approach, enhancing DNA damage while concomitantly blocking repair responses, provides the rationale for the clinical evaluation of SIRT6 modulators in the treatment of leukemia.

Combined assessment of WT1 and BAALC gene expression at diagnosis may improve leukemia-free survival prediction in patients with myelodysplastic syndromes

Several genes with relevant pathogenetic and prognostic value have been identified in patients with myelodysplastic syndromes. Overexpression of WT1 at diagnosis has been associated with increased progression to acute myeloid leukemia and reduced leukemia free survival. Conversely, few data are available on the prognostic value of BAALC gene overexpression in AML and MDS patients. We evaluated the prognostic value of the combined expression of WT1 and BAALC genes at diagnosis in 86 MDS patients who had been stratified according to IPSS and R-IPSS scoring systems. Our results suggest that in the whole group of patients, low levels of both WT1 and BAALC were associated with a favorable outcome (3-year LFS 74.5%, median not reached), whereas patients presenting high expression levels of both genes had the worst prognosis (3-year LFS 0%, median 12 months, p<0.001). More specifically, molecular profiling was especially useful for intermediate 1 and intermediate-2/high risk groups. This study suggests that evaluating WT1 and BAALC gene expression at diagnosis may improve standard risk stratification and possibly refine the therapeutic approach for MDS patients.