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POSTER HAEMATHOLOGICA, (ABSTRACT) VOL 88 (SUPPL) N.RO 15

POSTER,HAEMATHOLOGICA, (ABSTRACT) VOL 88 (SUPPL) N.RO 15

Background Ruxolitinib (Ruxo), an orally bioavailable and selective inhibitor of JAK1 and JAK2, significantly reduces splenomegaly and disease-related symptoms in patients with myelofibrosis (MF). However, no clear survival benefit has been demonstrated, which may in part reflect suboptimal drug exposure related to lower dosages needed to minimize hematological toxicity, specifically cytopenias. Furthermore, the optimal management of specific conditions such as leukocytosis or thrombocytosis in patients under ruxolitinib therapy is still undefined. In these cases, combining ruxolitinib with a cytoreductive agent like hydroxyurea (HU) might improve hematological response. Aims: To evaluate the efficacy and safety of Ruxo and HU combination. Methods This observational multicenter study, conducted from April 2012 to April 2017, enrolled 20 adult patients with a confirmed diagnosis of primary myelofibrosis (PMF), post-polycythemia vera (PPV-MF), or post-essential thrombocythemia (PET-MF) with hyperproliferative manifestations of the disease not controlled by Ruxo therapy. All patients we enrolled into the study had received Ruxo at a starting dose based on baseline platelet count. Patients were included into the study when Ruxo proved to be unable to reduce WBC and/or platelet count to within normal range (WBC Results The addition of HU was started after a median time of ruxolitinib monotherapy of 6.5 months (range 1-49.6 months): 17 patients (85%) started HU treatment due to lack of WBC control, whereas the remaining 3 patients (15%) started for the lack of platelet control. While on Ruxo monotherapy, ten patients (50%) needed a dose reduction due to hematological toxicity and three patients temporarily discontinued Ruxo due to severe thrombocytopenia (15%). After 14.5 months (range 2-195) median time of combination therapy in 8 patients the Ruxo daily doses increased (mean increase = 5.1 mg BID), in 9 the dose was unchanged despite the addition of HU, and only in three cases the ruxolitinib dose had to be reduced (mean reduction = 3.4 mg BID). Overall, the mean daily dose of Ruxo administered to the whole cohort of patients increased by 1.8 mg BID (P=.013), and only one patient had to discontinue Ruxo, due to severe thrombocytopenia. Non-hematological adverse events were not observed. Among the 17 patients who started combination therapy to control WBC count, 14 (82.3%) obtained a WBC response, whereas, among the three patients who started HU in association with Ruxo in order to reduce platelets count, two (66.6%) achieved a platelet response. In addition, 12 patients of the whole study cohort had clinical improvement in MF-associated symptomatic burden, with 9 of them showing spleen and symptoms response and the remaining three only spleen response. Thus, a clinical response of any type was obtained in 8 patients (40%) during Ruxo monotherapy and in 17 patients (85%) during Ruxo-HU combination (P=.003). Of note, all 8 patients in which Ruxo dose was increased during combination had at least one type of drug-related clinical response. Conclusion In conclusion, the combination of HU with Ruxo yielded a high clinical response rate and increased Ruxo exposure in patients with hyperproliferative forms of MF. The association was very well tolerated, and the hematological toxicities mostly and were generally manageable with dose reductions and/or supportive treatment. Disclosures Pane: AMGEN: Speakers Bureau; Novartis: Research Funding, Speakers Bureau; BMS: Speakers Bureau.

Large granular lymphocytes derive from two major lineages: one expressing the CD3 surface antigen (T-lymphocytes), and the other lacking this marker (NK-cells). Although developmental overlaps between natural killer cells and T-cells have been described, malignancies derived from these two cell types are considered as distinct lymphoid disorders.We report the case of a 30-year old man affected by a lymphoma/leukemia syndrome presenting with hepatosplenic lymphoma which rapidly transformed into aggressive NK-leukemia. Extensive flow cytometry studies and molecular analysis were repeated during the course of the disease, and showed an unexpected changing pattern.At diagnosis, flow cytometry analysis showed the co-existence of two cell populations, one CD56(+), CD3(+), TcRgd(+), and the other CD56(+), CD3(-) and TcRgd(-). Molecular analysis showed that the TcR genes had the same clonally rearranged pattern involving b, g and d genes in both populations. At disease relapse and during the terminal refractory phase, only CD3(-) cells were present.This is an unusual case of CD56(+) aggressive lymphoma/leukemia characterized by the clonal expansion of two phenotypically different cell populations, variably balanced during the course of the disease. The presence of the same TcR genomic rearrangement suggests the origin from a common progenitor able to differentiate along both T- and NK-pathways.

BACKGROUND CA 125 is a tumor marker used for the diagnosis and monitoring of ovarian carcinoma. This marker also has been found to be increased in patients with serosal effusion derived from nonneoplastic inflammatory disease and in a few instances of advanced non-Hodgkin lymphoma with serosal involvement. METHODS CA 125 levels were tested in the serum of 15 patients with acute myeloblastic leukemia (AML) at the time of diagnosis and in 3 patients with advanced leukemia with serosal involvement. In two patients with elevated serum CA 125 levels, a CA 125 assay was performed on leukemic cells and on the supernatant fluid of short term liquid culture. RESULTS Increased serum CA 125 was found in the three patients with acute leukemia with extramedullary localization and serosal effusion, whereas it was normal in 15 AML patients tested at the time of diagnosis. CA 125 was not detectable in leukemic cell extracts nor in the supernatant fluid of primary cultures. CONCLUSIONS These results indicate that leukemic cells were unable to produce CA 125 and suggest that its elevation in the serum is likely due to a serosal inflammatory reaction caused by the leukemic infiltration. Cancer 2000;88:75–8. © 2000 American Cancer Society.

CD66c is a surface (and intracellular) molecule bound to the membrane by a glycosyl-phosphatidylinositol anchor. While its expression on peripheral granulocytes is well recognized, less is known about its distribution in early steps of normal and neoplastic hematopoiesis. We analyzed by flow cytometry cell surface expression of CD66c on bone marrow cells from 4 healthy subjects and on bone marrow or peripheral blood cells from 127 patients with newly diagnosed hematologic malignancies: 70 de novo acute myeloid leukemias (AML), 6 refractory anemias with excess of blasts in transformation, 3 myeloid and 3 lymphoid blastic phases of chronic mye-logenous leukemia, 33 B-lineage and 6 T-lineage acute lymphoblastic leukemias (B- and T-ALL), and 3 B-cell and 3 T-cell non-Hodgkin's lymphomas in the leukemic phase. We found that in normal bone marrow CD66c expression was myeloid restricted, reaching its highest level on promyelocytes. As for de novo AML, slight expression of CD66c was found on 6/25 (24%) AML-M4 and only occasionally in other subgroups. In 9 out of 10 cases of acute promyelocytic leukemia, CD66c was totally absent, but antigen expression was easily detectable following in vitro exposure to all-trans retinoic add. Among lymphoid malignancies, CD10+ early-B-ALL consistently expressed the molecule (20/23 cases, or 87%) whereas both CD10- early-B ALL and Smlg+ B-ALL completely lacked it. Finally, dual staining with CD66c and CD10 proved to be a suitable tool for distinguishing even low percentages of residual leukemic cells (CD10+/CD66c+) from normal regenerating early-B cells (CD10+/CD66c-) in CD10+ early-B-ALL induced into remission.