Real-world Outcomes of Relapsed/Refractory Diffuse Large B-cell Lymphoma Treated With Polatuzumab Vedotin-based Therapy

: After FDA and EMA approval of the regimen containing polatuzumab vedotin plus rituximab and bendamustine (PolaBR), eligible relapsed/refractory diffuse large B-cell lymphoma (DLBCL) patients in Italy were granted early access through a Named Patient Program. A multicentric observational retrospective study was conducted focusing on the effectiveness and safety of PolaBR in everyday clinical practice. Fifty-five patients were enrolled. There were 26 females (47.3%), 32 patients were primary refractory and 45 (81.8%) resulted refractory to their last therapy. The decision to add or not bendamustine was at physician's discretion. Thirty-six patients underwent PolaBR, and 19 PolaR. The 2 groups did not differ in most of baseline characteristics. The final overall response rate was 32.7% (18.2% complete response rate), with a best response rate of 49.1%. Median disease-free survival was reached at 12 months, median progression-free survival at 4.9 months and median overall survival at 9 months, respectively. Overall, 88 adverse events (AEs) were registered during treatment in 31 patients, 22 of grade ≥3. Eight cases of neuropathy occurred, all of grades 1-2 and all related to polatuzumab. The two groups of treatment did not differ for effectiveness endpoints but presented statistically significant difference in AEs occurrence, especially in hematological AEs, in AEs of grade equal or greater than 3 and in incidence of neuropathy. Our data add useful information on the effectiveness of Pola(B)R in the setting of heavily pretreated DLBCL and may also suggest a better tolerability in absence of bendamustine without compromise of efficacy

MYC Rearranged Aggressive B-Cell Lymphomas: A Report on 100 Patients of the Fondazione Italiana Linfomi (FIL)

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A Specific Monoclonal Antibody (PG-B6) Detects Expression of the BCL-6 Protein in Germinal Center B Cells

The BCL-6 gene is frequently involved in translocations occurring at the 3q27 locus and is rear-ranged in approximately 30% of diffuse large cell lymphomas and in a small fraction of follicular lymphomas. The BCL-6 gene encodes for a Kruppel-type zinc-finger protein, the cell/tissue expression and function of which is unknown. In this study, we describe a new monoclonal anti-body (PG-B6) that is specificaly directed against a fixative-sensitive epitope on the amino-terminal region of the BCL-6protein. By immunocytochemical analysis, BCL-6 localizes in the nucleus where PG-B6 staining gives a microgranular/diffuse pattern with exclusion of the nucleoli. The main reactivity of PG-B6in tonsil and spleen is with the nuclei of germinal center B cells, whereas B cells within the mantle and marginal zones do not express BCL-6. No other lymphoid cells in the tonsil express BCL-6 except for a subset of CD3+/CD4+ intrafollicular and interfollicular T cells. A few lymphoid cells of unknown phenotype express BCL-6 in the thymus. Extra-lymphoid BCL-6 expression includes a weak nuclear positivity of epithelia. In non-Hodgkin's lymphomas, BCL-6 expression parallels that observed in normal lymphoid compartments, eg, expression in germinal center-derived tumors (follicular and diffuse large cell lymphomas), but not in mantle cell and marginal zone lymphomas. In most diffuse large cell lymphomas, the BCL-6 protein is expressed at high levels in cases with or without BCL-6 gene rearrangements. These findings indicate that BCL-6 expression is specifically regulated during B lymphocyte development and suggest that BCL-6 may play a role during B cell differentiation in the germinal center

ALK Expression Defines a Distinct Group of T/Null Lymphomas (“ALK Lymphomas”) with a Wide Morphological Spectrum

The t(2;5)(p23;q35) translocation associated with CD30-positive anaplastic large cell lymphoma results in the production of a NPM-ALK chimeric protein, consisting of the N-terminal portion of the NPM protein joined to the entire cytoplasmic domain of the neural receptor tyrosine kinase ALK. The ALK gene products were identified in paraffin sections by using a new anti-ALK (cytoplasmic portion) monoclonal antibody (ALKc) that tends to react more strongly than a previously described ALK1 antibody with the nuclei of ALK-expressing tumor cells after microwave heating in 1 mmol/L ethylenediaminetetraacetic acid buffer, pH 8.0. The ALKc monoclonal antibody reacted selectively with 60% of anaplastic large cell lymphoma cases (60 of 100), which occurred mainly in the first three decades of life and consistently displayed a T/null phenotype. This group of ALK-positive tumors showed a wide morphological spectrum including cases with features of anaplastic large cell lymphoma “common” type (75%), “lymphohistiocytic” (10%), “small cell” (8.3%), “giant cell” (3.3%), and “Hodgkin’s like” (3.3%). CD30-positive large anaplastic cells expressing the ALK protein both in the cytoplasm and nucleus represented the dominant tumor population in the common, Hodgkin’s-like and giant cell types, but they were present at a smaller percentage (often with a perivascular distribution) also in cases with lymphohistiocytic and small cell features. In this study, the ALKc antibody also allowed us to identify small neoplastic cells (usually CD30 negative) with nucleus-restricted ALK positivity that were, by definition, more evident in the small cell variant but were also found in cases with lymphohistiocytic, common, and “Hodgkin’s-like” features. These findings, which have not been previously emphasized, strongly suggest that the neoplastic lesion (the NPM-ALK gene) must be present both in the large anaplastic and small tumor cells, and that ALK-positive lymphomas lie on a spectrum, their position being defined by the ratio of small to large neoplastic cells. Notably, about 15% of all ALK-positive lymphomas (usually of the common or giant cell variant) showed a cytoplasm-restricted ALK positivity, which suggests that the ALK gene may have fused with a partner(s) other than NPM. From a diagnostic point of view, detection of the ALK protein was useful in distinguishing anaplastic large cell lymphoma cases of lymphohistiocytic and small cell variants from reactive conditions and other peripheral T-cell lymphoma subtypes, as well as for detecting a small number of tumor cells in lymphohemopoietic tissues. In conclusion, ALK positivity appears to define a clinicopathological entity with a T/null phenotype (“ALK lymphomas”), but one that shows a wider spectrum of morphological patterns than has been appreciated in the past

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Salvage immunochemotherapy and transplant consolidation is the standard treatment for relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). We tested a combination of Obinutuzumab and DHAP for treating R/R DLBCL. The primary end point was the rate of complete metabolic response (CMR). Secondary end points were stem cell mobilization, stem cell engraftment, overall survival, and feasibility. In this prospective, phase-2, single-arm trial (EudraCT 2014-004014-17) patients received the standard three doses of Obinutuzumab for the first cycle, and then one dose. Patients with CMR were consolidated with an autologous stem cell transplantation (ASCT). An interim analysis was provided after the first 29 patients to confirm the initial null hypothesis that at least 10/29 patients would achieve CMR. Among the 29 patients evaluated for the first stage only six patients (6/29, 21%) achieved CMR, thus, study enrollment was stopped. Nine patients exhibited extra-hematologic toxicities >= grade 3. Among the 19 patients that started stem cell mobilization, one failed (5%) and 18 achieved mobilization (95%). Of these 18 patients, nine were reinfused. Mobilization was observed in 16 patients (89%) after one or two apheresis rounds. The mean number of CD34 + cells mobilized was 5.8 x 10(6)/Kg (median: 5.5, IQR: 5-6.75). The mean number of reinfused CD34 + cells in the nine patients was 4.1 x 10(6)/Kg (median: 4.1, IQR: 3.5-5). Obinutuzumab combined with DHAP did not compromise stem cell mobilization or engraftment after ASCT in patients with DLBCL. However, Obinutuzumab + DHAP provided a lower CMR rate than expected