Giovanni Del Poeta

Integrated mutational and cytogenetic analysis identifies new prognostic subgroups in chronic lymphocytic leukemia.

The identification of new genetic lesions in chronic lymphocytic leukemia (CLL) prompts a comprehensive and dynamic prognostic algorithm including gene mutations and chromosomal abnormalities and their changes during clonal evolution. By integrating mutational and cytogenetic analysis in 1274 CLL samples and using both a training-validation and a time-dependent design, 4 CLL subgroups were hierarchically classified: (1) high-risk, harboring TP53 and/or BIRC3 abnormalities (10-year survival: 29%); (2) intermediate-risk, harboring NOTCH1 and/or SF3B1 mutations and/or del11q22-q23 (10-year survival: 37%); (3) low-risk, harboring +12 or a normal genetics (10-year survival: 57%); and (4) very low-risk, harboring del13q14 only, whose 10-year survival (69.3%) did not significantly differ from a matched general population. This integrated mutational and cytogenetic model independently predicted survival, improved CLL prognostication accuracy compared with FISH karyotype (P < .0001), and was externally validated in an independent CLL cohort. Clonal evolution from lower to higher risk implicated the emergence of NOTCH1, SF3B1, and BIRC3 abnormalities in addition to TP53 and 11q22-q23 lesions. By taking into account clonal evolution through time-dependent analysis, the genetic model maintained its prognostic relevance at any time from diagnosis. These findings may have relevant implications for the design of clinical trials aimed at assessing the use of mutational profiling to inform therapeutic decisions.

Analysis of regulatory T-cell changes in patients with idiopathic thrombocytopenic purpura receiving B cell–depleting therapy with rituximab

The effects of B-cell depletion with rituximab on regulatory T cells (Tregs) have not been determined. We investigated Tregs in patients receiving rituximab for chronic idiopathic thrombocytopenic purpura (ITP). The peripheral blood Tregs, identified as CD4+FOXP3+ T cells, were measured by flow cytometry prior to and after the immunotherapy. In addition, Tregs were analyzed for their usage of the T-cell receptor (TCR) beta-variable (VB) region gene as well as their regulatory function as assessed by cell proliferation assays. Pretreatment data revealed a reduced number and a defective suppressive capacity of Tregs in ITP patients compared with control individuals. In addition, Tregs showed a polyclonal spectratype. Patients, particularly responders, showed restored numbers of Tregs as well as a restored regulatory function upon treatment with rituximab. These results indicate that patients with active ITP have a defective T regulatory cell compartment that can be modulated by a B cell-targeted therapy.

CD38/CD31, the CCL3 and CCL4 Chemokines, and CD49d/Vascular Cell Adhesion Molecule-1 Are Interchained by Sequential Events Sustaining Chronic Lymphocytic Leukemia Cell Survival

CD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Despite evidence that both molecules are involved in interactions occurring between CLL and normal cells in the context of CLL-involved tissues, a functional link is still missing. Using gene expression profiles comparing CD38(+)CD49d(+) versus CD38(-)CD49d(-) CLL cells, we showed overexpression of the CCL3 and CCL4 chemokines in cells from the former group. These chemokines were also up-regulated by CD38 signals in CLL; moreover, CCL3 was expressed by CLL cells from bone marrow biopsies (BMB) of CD38(+)CD49d(+) but not CD38(-)CD49d(-) cases. High levels of CCR1 and, to a lesser extent, CCR5, the receptors for CCL3 and CCL4, were found in CLL-derived monocyte-macrophages. Consistently, CCL3 increased monocyte migration, and CD68(+) macrophage infiltration was particularly high in BMB from CD38(+)CD49d(+) CLL. Conditioned media from CCL3-stimulated macrophages induced endothelial cells to express vascular cell adhesion molecule-1 (VCAM-1), the CD49d ligand, likely through tumor necrosis factor alpha overproduction. These effects were apparent in BMB from CD38(+)CD49d(+) CLL, where lymphoid infiltrates were characterized by a prominent meshwork of VCAM-1(+) stromal/endothelial cells. Lastly, CD49d engagement by VCAM-1 transfectants increased viability of CD38(+)CD49d(+) CLL cells. Altogether, CD38 and CD49d can be thought of as parts of a consecutive chain of events ultimately leading to improved survival of CLL cells.

Toward Optimization of Postremission Therapy for Residual Disease–Positive Patients With Acute Myeloid Leukemia

PURPOSE Despite the identification of several baseline prognostic indicators, the outcome of patients with acute myeloid leukemia (AML) is generally heterogeneous. The effects of autologous (AuSCT) or allogeneic stem-cell transplantation (SCT) are still under evaluation. Minimal residual disease (MRD) states may be essential for assigning patients to therapy-dependent risk categories. PATIENTS AND METHODS By multiparametric flow cytometry, we assessed the levels of MRD in 142 patients with AML who achieved complete remission after intensive chemotherapy. RESULTS A level of 3.5 x 10(-4) residual leukemia cells (RLCs) after consolidation therapy was established to identify MRD-negative and MRD-positive cases, with 5-year relapse-free survival (RFS) rates of 60% and 16%, respectively (P < .0001) and overall survival (OS) rates of 62% and 23%, respectively (P = .0001). Of patients (n = 77) who underwent a transplantation procedure (56 AuSCT and 21 SCT procedures); 42 patients (55%) were MRD positive (28 patients who underwent AuSCT and 14 patients who underwent SCT) and 35 patients (45%) were MRD negative (28 patients who underwent AuSCT and seven who underwent SCT). MRD-negative patients had a favorable prognosis, with only eight (22%) of 35 patients experiencing relapse, whereas 29 (69%) of 42 MRD-positive patients experienced relapse (P < .0001). In this high-risk group of 42 patients, we observed that 23 (82%) of 28 of those who underwent AuSCT experienced relapse, whereas six (43%) of 14 who underwent SCT experienced relapse (P = .014). Patients who underwent SCT also had a higher likelihood of RFS (47% v 14%). CONCLUSION A threshold of 3.5 x 10(-4) RLCs postconsolidation is critical for predicting disease outcome. MRD-negative patients have a good outcome regardless of the type of transplant they receive. In the MRD-positive group, AuSCT does not improve prognosis and SCT represents the primary option.

Molecular and clinical features of chronic lymphocytic leukaemia with stereotyped B cell receptors: Results from an Italian multicentre study

A fraction of chronic lymphocytic leukaemia (CLL) cases carry highly homologous B‐cell receptors (BCR), i.e. characterized by non‐random combinations of immunoglobulin heavy‐chain variable (IGHV) genes and heavy‐chain complementarity determining region‐3 (HCDR3), often associated with a restricted selection of IGVK/L light chains. Such ‘stereotyped’ BCR occur more frequently in CLL with unmutated (UM) than mutated (M) IGHV genes. We analysed 1426 IG rearrangements (from 1398 CLL cases) by a clustering driven by HCDR3 similarities. Molecular findings were correlated to time‐to‐treatment (TTT) and presence of known prognosticators. Sixty‐nine clusters (319 IG‐rearrangements, 22·4%) with stereotyped BCR were identified. Among 30 confirmed clusters (≥3 IG‐rearrangements/cluster), we found 14 novel clusters, of which 11 had M IG rearrangements (M clusters) and predominantly (8/11) used IGHV3 subgroup genes. Recurrent cluster‐biased amino acid changes were found throughout IGHV sequences of these ‘M clusters’. Regarding clinical outcome: (i) UM CLL from the IGHV1‐2/1‐3/1‐18/1‐46/7‐4‐1/IGKV1‐39 cluster had poorer prognosis than UM/M cases, or UM cases using the same IGHV genes but not in clusters; (ii) M CLL from the IGHV3‐21/IGLV3‐21 cluster had TTT similar to UM CLL, and shorter than M CLL expressing IGHV3‐21 but not in cluster. Altogether, our analysis identified additional molecular and clinical features for CLL expressing stereotyped BCR.

Consolidation and maintenance immunotherapy with rituximab improve clinical outcome in patients with B-cell chronic lymphocytic leukemia†

Rituximab in sequential combination with fludarabine (Flu) allowed patients with B‐cell chronic lymphocytic leukemia (B‐CLL) to achieve higher remission rates and longer response duration. Based on their recent experience in indolent non‐Hodgkin lymphomas, in this study, the authors attempted to demonstrate whether consolidation/maintenance therapy with rituximab could prolong the response duration in this patient population.

Incidence of chromosome abnormalities and clinical significance of karyotype in de novo acute myeloid leukemia

Cytogenetic studies with high-resolution banding were performed on specimens from 132 consecutive patients with de novo acute myeloid leukemia (AML). All patients were treated according to therapeutic protocols in the same institution. Clonal abnormalities were detected in 97 of the 124 patients in whom an adequate number of mitoses was obtained (78.2%). Neither sex, FAB classification, WBC, or the extent of bone marrow infiltrate affected the rate of chromosomal aberrations, whereas patients younger than 40 years had a greater proportion of normal karyotypes (p = 0.047). Two different chromosomal classifications were evaluated: the presence of normal and abnormal metaphases (NN-AN-AA classification), and a classification in cytogenetic categories, the latter being based on the frequency of cytogenetic abnormalities. Both classifications were found to correlate significantly with the clinical outcome. They also showed independent prognostic significance when age, sex, and FAB morphology were considered in a multivariate analysis. Two abnormalities were closely associated with specific clinical-pathologic subsets of AML. All the 15 patients with t(15;17) had acute promyelocytic leukemia; this translocation was not found in any other subset of AML. Eight of the nine patients presenting rearrangements at 11q23 belonged to a FAB subset with monocytic differentiation (M4 and M5). Our data suggest that cytogenetic findings should influence the therapeutic approach to AML. In particular, young patients with karyotypes associated with poor responses may be considered for more eradicating treatments, including allogenic bone marrow transplantation.

Molecular prediction of durable remission after first-line fludarabinecyclophosphamide-rituximab in chronic lymphocytic leukemia

Fludarabine, cyclophosphamide, and rituximab (FCR) has represented a significant treatment advancement in chronic lymphocytic leukemia (CLL). In the new scenario of targeted agents, there is an increasing interest in identifying patients who gain the maximum benefit from FCR. In this observational multicenter retrospective analysis of 404 CLL patients receiving frontline FCR, the combination of three biomarkers that are widely tested before treatment (IGHV mutation status, 11q deletion and 17p deletion; available in 80% of the study cohort) allowed to identify a very low-risk category of patients carrying mutated IGHV genes but neither 11q or 17p deletion that accounted for 28% of all cases. The majority of very low-risk patients (71%) remained free of progression after treatment and their hazard of relapse decreased after 4 years from FCR. The life expectancy of very low-risk patients (91% at 5 years) was superimposable to that observed in the matched normal general population, indicating that neither the disease nor complications of its treatment affected survival in this favorable CLL group. These findings need a prospective validation and may be helpful for the design of clinical trials aimed at comparing FCR to new targeted treatments of CLL, and, possibly, for optimized disease management.

Cytogenetic and molecular diagnostic characterization combined to postconsolidation minimal residual disease assessment by flow cytometry improves risk stratification in adult acute myeloid leukemia

A total of 143 adult acute myeloid leukemia (AML) patients with available karyotype (K) and FLT3 gene mutational status were assessed for minimal residual disease (MRD) by flow cytometry. Twenty-two (16%) patients had favorable, 115 (80%) intermediate, and 6 (4%) poor risk K; 19 of 129 (15%) carried FLT3-ITD mutation. Considering postconsolidation MRD status, patients with good/intermediate-risk K who were MRD(-) had 4-year relapse-free survival (RFS) of 70% and 63%, and overall survival (OS) of 84% and 67%, respectively. Patients with good- and intermediate-risk K who were MRD(+) had 4-year RFS of 15% and 17%, and OS of 38% and 23%, respectively (P < .001 for all comparisons). FLT3 wild-type patients achieving an MRD(-) status, had a better outcome than those who remained MRD(+) (4-year RFS, 54% vs 17% P < .001; OS, 60% vs 23%, P = .002). Such an approach redefined cytogenetic/genetic categories in 2 groups: (1) low-risk, including good/intermediate K-MRD(-) with 4-year RFS and OS of 58% and 73%, respectively; and (2) high risk, including poor-risk K, FLT3-ITD mutated cases, good/intermediate K-MRD(+) categories, with RFS and OS of 22% and 17%, respectively (P < .001 for all comparisons). In AML, the integrated evaluation of baseline prognosticators and MRD improves risk-assessment and optimizes postremission therapy.

CD49d Is the Strongest Flow Cytometry–Based Predictor of Overall Survival in Chronic Lymphocytic Leukemia

PURPOSE Although CD49d is an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL), definitive validation evidence is lacking. A worldwide multicenter analysis was performed using published and unpublished CLL series to evaluate the impact of CD49d as an overall (OS) and treatment-free survival (TFS) predictor. PATIENTS AND METHODS A training/validation strategy was chosen to find the optimal CD49d cutoff. The hazard ratio (HR) for death and treatment imposed by CD49d was estimated by pooled analysis of 2,972 CLLs; Cox analysis stratified by center and stage was used to adjust for confounding variables. The importance of CD49d over other flow cytometry-based prognosticators (eg, CD38, ZAP-70) was ranked by recursive partitioning. RESULTS Patients with ≥ 30% of neoplastic cells expressing CD49d were considered CD49d+. Decrease in OS at 5 and 10 years among CD49d+ patients was 7% and 23% (decrease in TFS, 26% and 25%, respectively). Pooled HR of CD49d for OS was 2.5 (2.3 for TFS) in univariate analysis. This HR remained significant and of similar magnitude (HR, 2.0) in a Cox model adjusted for clinical and biologic prognosticators. Hierarchic trees including all patients or restricted to those with early-stage disease or those age ≤ 65 years always selected CD49d as the most important flow cytometry-based biomarker, with negligible additional prognostic information added by CD38 or ZAP-70. Consistently, by bivariate analysis, CD49d reliably identified patient subsets with poorer outcome independent of CD38 and ZAP-70. CONCLUSION In this analysis of approximately 3,000 patients, CD49d emerged as the strongest flow cytometry-based predictor of OS and TFS in CLL.