Patients with ≥ 20 × 10(9)/L Platelets at Baseline May Have a Prompt Response to Romiplostim During the Early Phase of Treatment: an Italian Single-Institution Experience.

Patients with chronic immune thrombocytopenia treated with romiplostim may benefit from a higher starting dose when a rapid increase in count is needed, but it could be avoided in those with a prompt response to the standard dosage. We hypothesized that a platelet count ≥ 20 x 109/l at baseline could distinguish subjects with such response from those with a delayed one during the early phase of treatment. Our work is a retrospective and single-institution analysis comparing the median platelet count, the median weekly dosage of romiplostim and the median number of weekly platelet counts < 50 x 109/l between patients with a baseline ≥ 20 x 109/l platelets (n=10, 2 splenectomized) and those with a lower one (n=8, 3 splenectomized) during the first month of treatment with romiplostim. The results show a higher median platelet count (79,5 vs 40,5 x 109/l, p=0,002) and a lower median dose of romiplostim (1 vs 2 mcg/kg/week, p=0,01) in subjects with a baseline ≥ 20 x 109/l  platelets, who also had a trend of less weekly counts < 50  x 109/l  platelets (1 vs 2, p=0,054). These data suggest that patients with ≥ 20 x 109/l platelets at baseline may achieve a prompt response with the standard dose of romiplostim, but further and larger data are needed in order to assess whether it can be considered in clinical practice

Impact of mutational status on outcomes in myelofibrosis patients treated with ruxolitinib in the COMFORT-II study

The JAK1/JAK2 inhibitor ruxolitinib produced significant reductions in splenomegaly and symptomatic burden and improved survival in patients with myelofibrosis (MF), irrespective of their JAK2 mutation status, in 2 phase III studies against placebo (COMFORT-I) and best available therapy (COMFORT-II). We performed a comprehensive mutation analysis to evaluate the impact of 14 MF-associated mutations on clinical outcomes in 166 patients included in COMFORT-II. We found that responses in splenomegaly and symptoms, as well as the risk of developing ruxolitinib-associated anemia and thrombocytopenia, occurred at similar frequencies across different mutation profiles. Ruxolitinib improved survival independent of mutation profile and reduced the risk of death in patients harboring a set of prognostically detrimental mutations (ASXL1, EZH2, SRSF2, IDH1/2) with an hazard ratio of 0.57 (95% confidence interval: 0.30-1.08) vs best available therapy. These data indicate that clinical efficacy and survival improvement may occur across different molecular subsets of patients with MF treated with ruxolitinib

Impact of JAK2(V617F) mutation status on treatment response to anagrelide in essential thrombocythemia: an observational, hypothesis-generating study

Nicola Cascavilla,1 Valerio De Stefano,2 Fabrizio Pane,3 Alessandro Pancrazzi,4 Alessandra Iurlo,5 Marco Gobbi,6 Francesca Palandri,7 Giorgina Specchia,8 A Marina Liberati,9 Mariella D&rsquo;Adda,10 Gianluca Gaidano,11 Rajmonda Fjerza,4 Heinrich Achenbach,12 Jonathan Smith,13 Paul Wilde,13 Alessandro M Vannucchi41Division of Hematology, Casa Sollievo della Sofferenza Hospital, IRCCS, San Giovanni Rotondo, Italy; 2Institute of Hematology, Catholic University, Rome, Italy; 3Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy; 4Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; 5Oncohematology Unit, Fondazione IRCCS Ca&rsquo; Granda, Ospedale Maggiore Policlinico, Milan, Italy; 6IRCCS AOU San Martino, Genova, Italy; 7Department of Specialistic, Diagnostic and Experimental Medicine, St Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy; 8Unit of Hematology with Transplantation, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy; 9Ospedale Santa Maria, Terni, Italy; 10Division of Hematology, Azienda Ospedaliera Spedali Civili di Brescia, Brescia, Italy; 11Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, Novara, Italy; 12Research and Development, Shire GmbH, Eysins, Switzerland; 13Shire Pharmaceutical Development Ltd, Basingstoke, United KingdomAbstract: A JAK2(V617F) mutation is found in approximately 55% of patients with essential thrombocythemia (ET), and represents a key World Health Organization diagnostic criterion. This hypothesis-generating study (NCT01352585) explored the impact of JAK2(V617F) mutation status on treatment response to anagrelide in patients with ET who were intolerant/refractory to their current cytoreductive therapy. The primary objective was to compare the proportion of JAK2-positive versus JAK2-negative patients who achieved at least a partial platelet response (&le;600&times;109/L) after anagrelide therapy. Of the 47 patients enrolled, 46 were included in the full analysis set (JAK2-positive, n=22; JAK2-negative, n=24). At 12&nbsp;months, 35 patients (n=14 and n=21, respectively) had a suitable platelet sample; of these, 74.3% (n=26) achieved at least a partial response. The response rate was higher in JAK2-positive (85.7%, n=12) versus JAK2-negative patients (66.7%, n=14) (odds ratio [OR] 3.00; 95% confidence interval [CI] 0.44, 33.97). By using the last observation carried forward approach in the sensitivity analysis, which considered the imbalance in patients with suitable samples between groups, the overall response rate was 71.7% (n=33/46), with 77.3% (n=17/22) of JAK2-positive and 66.7% (n=16/24) of JAK2-negative patients achieving at least a partial response (OR 1.70; 95% CI 0.39, 8.02). There was no significant change in median allele burden over 12&nbsp;months in the 12 patients who achieved a response. In conclusion, the overall platelet response rate was high in both JAK2-positive and JAK2-negative patients; however, a larger study would be required to confirm the differences observed according to JAK2(V617F) mutation status.Keywords: essential thrombocythemia, mutation, JAK2, anagrelide, treatment response, allele burde

Long-term survival and blast transformation in molecularly annotated essential thrombocythemia, polycythemia vera, and myelofibrosis

Janus kinase 2 (JAK2) mutations define polycythemia vera (PV). Calreticulin (CALR) and myeloproliferative leukemia virus oncogene (MPL) mutations are specific to JAK2-unmutated essential thrombocythemia (ET) and primarymyelofibrosis (PMF). We examined the effect of these mutations on long-term disease outcome. One thousand five hundred eighty-one patients from the Mayo Clinic (n = 826) and Italy (n = 755) were studied. Fifty-eight percent of Mayo patients were followed until death; median survivals were 19.8 years in ET (n = 292), 13.5 PV (n = 267; hazard ratio [HR], 1.8; 95% confidence interval [CI], 1.4-2.2), and 5.9 PMF(n = 267; HR, 4.5; 95% CI, 3.5-5.7). The survival advantage of ET over PV was not affected by JAK2/CALR/MPL mutational status. Survival in ET was inferior to the age-and sex-matched US population (P < .001). In PMF (n = 428), but not in ET (n = 576), survival and blast transformation (BT) were significantly affected by mutational status; outcome was best in CALR-mutated and worst in triple-negative patients: median survival, 16 vs 2.3 years (HR, 5.1; 95% CI, 3.2-8.0) and BT, 6.5% vs 25% (HR, 7.6; 95% CI, 2.8-20.2), respectively. We conclude that life expectancy in morphologically defined ET is significantly reduced but remains superior to that of PV, regardless of mutational status. In PMF, JAK2/CALR/MPL mutational status is prognostically informative

Tie2 expressing monocytes in the spleen of patients with primary myelofibrosis

Primary myelofibrosis (PMF) is a Philadelphia-negative (Ph-) myeloproliferative disorder, showing abnormal CD34 + progenitor cell trafficking, splenomegaly, marrow fibrosis leading to extensive extramedullary haematopoiesis, and abnormal neoangiogenesis in either the bone marrow or the spleen. Monocytes expressing the angiopoietin-2 receptor (Tie2) have been shown to support abnormal angiogenic processes in solid tumors through a paracrine action that takes place in proximity to the vessels. In this study we investigated the frequency of Tie2 expressing monocytes in the spleen tissue samples of patients with PMF, and healthy subjects (CTRLs), and evaluated their possible role in favouring spleen angiogenesis. We show by confocal microscopy that in the spleen tissue of patients with PMF, but not of CTRLs, the most of the CD14 + cells are Tie2 + and are close to vessels; by flow cytometry, we found that Tie2 expressing monocytes were Tie2 + CD14 low CD16 bright CDL62 - CCR2 - (TEMs) and their frequency was higher (p = 0.008) in spleen tissue-derived mononuclear cells (MNCs) of patients with PMF than in spleen tissue-derived MNCs from CTRLs undergoing splenectomy for abdominal trauma. By in vitro angiogenesis assay we evidenced that conditioned medium of immunomagnetically selected spleen tissue derived CD14 + cells of patients with PMF induced a denser tube like net than that of CTRLs; in addition, CD14 + Tie2 + cells sorted from spleen tissue derived single cell suspension of patients with PMF show a higher expression of genes involved in angiogenesis than that found in CTRLs. Our results document the enrichment of Tie2 + monocytes expressing angiogenic genes in the spleen of patients with PMF, suggesting a role for these cells in starting/maintaining the pathological angiogenesis in this organ