ALBERT

Description: Background: MPNs including Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF), are clonal hematopoietic diseases in which the discovery of molecular driver mutations (JAK2, CALR, MPL) has deeply modified diagnostic approach in recent years. To date available data on epidemiology of MPNs and perspective analysis are rare. Our aim is to study the incidence of MPN Ph negative in a specific region of Italy named Latium and its variability across five years. Moreover we prospectively report the general features of our population. Method: We present here the prospective epidemiologic analysis of 1116 adult patients affected by MPNs (PV=289, ET=550, PMF=209) diagnosed according to 2008 WHO criteria, from January 2011 to December 2015 in 15 hematological Centers (5 academic and 10 community-based Hospitals) in Latium. A total of 289 PV, 550 ET and 209PMF were identified. The overall incidence rate of 289PV was 1.0/105 in 2011 and 2012, 1.1/105 in 2013, 0.9/105 in 2014 and 2015. The overall incidence rate of 550ET was 2.0/105 in 2011, 2.4/105 in 2012, 2.2/105 in 2013, 1.8/105 in 2014 and 1,2/105 in 2015 and the overall incidence rate of 209PMF was 0.7/105 in 2011 and 2012, 1.0/105 in 2013, 0.7/105 in 2014 and 0.5/105 in 2015. We have observed also 63 cases of MPNu (36M/32F) and the incidence rate was 0.3/105 in 2011 and 2012, 0.14/105 in 2013, 0.24/105 in 2014 and 0.22/105 in 2015. Baseline features of PV, ET and PMF patients are summarized in table 1. We have also analyzed the presence of comorbidities including obesity, arhythmia and neoplasia observed at the diagnosis in 1.6, 6.2 and 4% of all population, respectively; thirty-five percent of 1116 pts presented other comorbidities such as diabetes, inflammatory bowel disease, renal and liver failure. As thrombotic risk factors we considered diabetes, dislipidemia, smoke, essential hypertension and thrombophilia observed in 11,8, 16,2, 13,2, 51,7 and 3% of total pts, respectively. Conclusions: We confirm in our prospective observational protocol the overall incidence of MPN Ph negative, previously reported in the literature and the major incidence of male gender in PV and PMF, female in of ET. The annual incidence from 2011-2015 in Latium is remained substantially the same during the observation period. The decreasing trend observed in 2015 is probably due to the different update of some Centers that was done in October 2015 not including patients diagnosed in the last two months. Disclosures Latagliata: Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria; Shire: Honoraria. Breccia:Pfizer: Honoraria; Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Ariad: Honoraria. Cimino:Celgene: Honoraria; Bristol-Mayer: Honoraria.

Description: Background Thrombotic episodes are the major complication in the follow-up of Philadelphia negative Myeloproliferative Neoplasms (MPN), with high morbidity and mortality, as reported in several retrospective studies. At present, however, few prospective data are available on the early incidence of these complications. Methods To address this issue, we report on 1087 patients [M/F 508/579, median age 67.6 years, interquartile range (IQR) 55.2 - 75.9] with newly diagnosed MPN enrolled in the prospective database of our regional cooperative group since January 2011. Of them, 571 (52.5%) had Essential Thrombocythemia (ET), 303 (27.9%) Polycythemia Vera (PV) and 213 (19.6%) Primary Myelofibrosis (PMF). The main clinical features at diagnosis of the whole cohort and according to the different MPNs are reported in the Table 1. Results On the whole, 22 episodes of thrombotic complications were reported in 1087 patients (2.0%) at a median interval from diagnosis of 18.2 months (IQR 7.4 - 29.7): in particular, 15 (68.1%) were arterial (8 cerebral, 2 coronaric, 4 in the lower limbs, 1 splancnic) and 7 (31.9%) venous (5 in the lower limbs and 2 in the upper limbs). As to the incidence of early thrombosis in the different MPNs, they were 13/571 (2.2%) in ET patients, 5/303 (1.6%) in PV patients and 4/213 (1.8%) in PMF patients (p=0.810): median time from diagnosis to thrombotic event was also similar in the 3 MPNs (p=0.311). The 4-year cumulative Thrombosis-Free Survival (TFS) of the whole cohort was 97.3% (95%CI 96.0 - 98.6): there was no difference among the 3 MPNs as to 4-year TFS [96.7% (95%CI 94.8 - 98.6) in ET, 97.8% (95%CI 95.9 - 99.7) in PV and 98.7% (95%CI 96.9 - 100) in PMF, respectively, p=0.668). Several clinical features at diagnosis (age, gender, Hb levels, WBC and PLT counts, spleen enlargement, JAK-2 V617F mutation and previous thrombotic events) were evaluated for a role in predicting thrombotic events: only age (p=0.009) and previous thrombotic events (p=0.009) were significant. Conclusions The incidence of early thrombosis seems low in the first 4 years after diagnosis of MPN based on our prospective database, without any difference among ET, PV and PMF: it is worth of note that only age and previous thrombotic events had a predictive role, thus confirming many retrospective reported data and reinforcing the prognostic value of old scoring system for thrombotic risk in MPN. Table 1 Table 1. Disclosures Breccia: Ariad: Honoraria; Pfizer: Honoraria; Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria. Latagliata:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria; Shire: Honoraria.

Description: INTRODUCTION: Bisphosphonates (Bsf) are a recognized and effective class of drugs used intravenously to treat cancer-related conditions, such as multiple myeloma (MM) and others solid tumours for the prevention of pathologic fractures, and in oral form to prevent osteoporosis and osteopenia. Some other activities are described as immunomodulating effects. Evolution of bisphosphonates related osteonecrosis of the jaw (BRONJ) is a rare complication with the risk increasing the longer the patient uses the drug. Pamidronate and Zolendronic acid can induce BRONJ in 0,8% – 12% of patients as described in different casistics. In this study we want describe the evolution and outcome of the BRONJ in a multicentric casistic. MATERIAL AND METHODS: In our group we observed 55 pts with Multiple Myeloma (MM) who developed BRONJ; immunoglobulin isotype was: 25 pts IgG-κ; 6 pts IgG-λ, 12 pts IgA-κ; 3 pt IgA-λ, 5 pts IgM-κ, 3 pts MM light chain κ and 1 pt MM light chain λ. Median age was 72 years (range 56–95), male 16/female 39. All patients were treated with Bsf: Pamidronate 1 pts (1,8 %), Zolendronate 36 pts (65,5 %), Pamidronate/zolendronate 18 pts (32,7 %). The average dose of Pamidronate was 2.022 mg (range 90–6.750 mg) and of zoledronate was 84 mg (range 4–256 mg). Anatomic localisation of the BRONJ was: mandible 29 pts (52,7%); maxilla 22 pts (40%); mandible/maxilla 4 cases (7,3 %). The most common trigger for BRONJ was dentoalveolar surgery, including extractions (43 cases-78, 4%), dental implant placement (3 patients-5, 4%), periodontal disease (5 cases-9 %), and in 3 patients with dental prothesis (5, 4%); 1 patient (1,8%) developed BRONJ spontaneously. All patients stopped bsf therapy after BRONJ diagnosis. RESULTS: All patients were treated with conservative treatment such as antibiotic therapy. In 18 patients (32,7%) antibiotic therapy was the only treatment used. Six patients (10,9%) received antibiotic associated with surgical debridement of necrotic bone. Sixteen patients (29%) were treated with antibiotic therapy in combination with hyperbaric oxygen therapy/ozonotherapy and curettage; twelve patients (21, 8%) required sequestrectomy in association with antibiotic and oxygen/hyperbaric therapy. Three patients (5,4%) refused any therapy. Resolution was observed in 19 cases (34,5%); 24 patients (43,6%) improved as pain and as control of infection of the soft and hard tissue. The osteonecrosis was invariated in 9 patients (16,3%); three patients (5, 4%) did not responde to treatment. CONCLUSIONS: Our retrospective study demonstrate that, in established BRONJ, clinical improvement can be obtained in a high percentage (78%), with a complete resolution of bone necrosis in one third of patients. Surgical treatment, associated with antibiotic therapy, is the most effective treatment to eradicate the necrotic bone. The effectiveness of hyperbaric oxygen therapy is not nowadays well determined, but in our experience it demonstrated its utility. Because the most common trigger for BRONJ was dental extractions, prior to treatment with bsf, all patients should have a thorough oral examination and should be completed all invasive dental procedures, achieving optimal periodontal health. With increased recognition and follow up of the BRONJ, it is likely that our knowledge will improve the risk of developing BRONJ and obtaining in more patients a complete remission.

Description: Abstract 5065 The Latium is a region of central Italy that counts approximatively 5.600.000 of residents. We reported herein a preliminary analysis of 1572 patients affected by MPN diagnosed in the last 20 years and treated in 9 of the Centers belonging to our group. Our centers are mainly located in Rome (7 centers) and neighboring districts (2 centers, Latina and Viterbo). The diagnosis was performed according to PVSG criteria until 2001 and then according to the WHO criteria: the majority of the patients underwent bone marrow biopsy. 218 patients were affected by primary myelofibrosis (PMF), 779 by Essential thrombocytemia (ET) and 575 by Policytemia Vera (PV). Epidemiological and clinical findings of all patients at diagnosis as well as thrombotic complications and evolution are reported in the table:ET (779 pts)PV (575 pts)PMF (218 pts)M/F288/491350/225134/84Age (yrs)59 (r: 20-93)60 (r: 19-91)67 (r: 30-86)WBC (x109/L)9192 (+/− 3483 SD)10423 (+/− SD 4307)13313 (+/−5220)Hb (g/dL)13, 9 (+/− 1,8)18,1 (+/− 2,3)11,7 (+/− 2,8)Plts (x 109/L)877 (+/− 353)445 (+/−247)457 (+/− 358)Splenomegaly (%)193579Bone marrow biopsy (performed/total))557/779 (71,5%)254/575 (44,2%)207/218 (95%)JAK-2 V617F mut (%)284/484 (59%)256/369 (69,4%)69/116 (59,5 %)Jak-2 allele burdenPerformed in 188/284 cases 26,49% (SD +/− 24)Performed in 199/256 cases: 59,4 % (SD +/−30,9)Performed in 51/69 cases 57,5% (SD +/− 29,4)Median Follow-up (years)7,157,863,89Thrombosis pre-diagnosis of MPNN. of patients (%)108/779 (13,8%)100/575 (17,4%)29/218 (13,3%)(arterial+venous)74+3476+2424+5Thrombosis post diagnosis of MPNN. of patients (%)71/779 (9,1%)66/575 (11,5%)20/218(9,17%)(arterial+venous)42+2942+2412+8EvolutionMyelofibrosis9/779 (1,1%)24/575 (4,1%)AML9/779 (1,1%)13/575 (2,3%)17/143 (11,8%) Comments: In our opinion, this casistic of patients with different types of MPNs reflects clinical presentation and evolution of three variants of the same disease. Many clinical findings in our unselected cohort of patients are similar to those reported in literature; in particular, thrombotic events were seen in about 13 – 17% of patients, without any correlation with Jak-2 status in both pre-diagnosis and follow-up. However, 2 main differences were noted: a lower incidence of JAK-2 V617F mutation among our PV patients and a lower rate of evolution in myelofibrosis and AML among our ET and PV patients. Both these features warrant further insights to be fully elucidated. Disclosures: No relevant conflicts of interest to declare.

Description: Thrombotic events are major complications in patients (pts) affected by Essential Thrombocytemia (ET) and Polycytemia Vera (PV). To compare thrombotic risk in these 2 groups, we evaluated retrospectively our database of 1249 ET and 623 PV pts diagnosed and followed in 11 hematological centers in the Latium region between 1/1980 and 12/2010: the diagnosis was done according to PVSG, WHO 2001 and 2008criteria based on the time of first observation. Baseline features of ET pts: 797F/452M,median age 62.9 yrs (range 19-96),median WBC count 8.8 x 109/L (range 1.2-57.7), median PLT count 812 x 109/L (range 457-3582), median Hb level 14.0 g/dl (range 6-20.5), JAK-2V617F positivity 59.7% with a median allele burden of 19,6% (range 0.2- 99.9), spleen enlargement in 18.7% of pts, previous thrombosis223/1239 evaluable pts (17.9%) [arterial 176/223 (14.1%), venous 47/223 (3.8%)]. Baseline features of PV pts: 289F/334M, median age 63.0yrs (range 21-91), median WBC count 10.1 x 109/L (range 3.5-37.6), median PLT count 457 x 109/L (range 169-1790), median Hb level 18.2 g/dl (range 10.5-24.8), JAK-2V617F positivity 94.3% with a median allele burden of 59.1% (range 0.3-99.9), spleen enlargement in 42% of patients, previous thrombosis 146/617 evaluable pts (23.7%)[arterial 114/617 (18.5%), venous 32/617 (5,2%)].in the ET cohort, after a median follow-up of 7.7 yrs, thrombotic complications were seen in 107/1141 evaluable pts (9.4%) [arterial60 (5.25%), venous 47 (4.11%)]; in the PV cohort, after a median follow-up of 8.5 yrs, thrombotic complications were seen in 107/623pts (17.2%) [arterial 67 (10.8%),venous 40 (6.4%)].All common risk factors for thrombosis were evaluated in multivariate analysis, searching the cut-off number for continuous variables with ROC curves. The significant variables at multivariate analysis for ET and PV pts are shown in the table; age, previous thromboses and spleen enlargement were risk factors in ET pts, while previous thromboses and JAK-2V617F allele burden were risk factors in PV pts. PLT count above ROC value seemed to be a protective factor in both cohorts. In conclusion, in contrast with the tendency to evaluate in a similar manner the thrombotic risk of PV and ET, data from our retrospective database showed that these 2 groups should be considered populations with different risk factors for thrombosis. Table 1.Putative prognostic factorsPolycythemia VeraEssential ThrombocythemiaHR95% C.I.pHR95% C.I .pPrevious thromboses2,311,13 - 4,740,021,871,08 -3,230,026Age ≥ 60 y1,540,79 - 2,990,211,901,18 - 3,060,009JAK2V617FPV: allelic burden ≥ 81% ET: pos1,951,03 - 3,710,040,760,48 - 1,210,25Plt countPV ≥ 452.109/L ET ≥ 944.109/L0,490,25 - 0,950,040,520,31 - 0,890,017Spleen enlargement0,670,34 -1,310,241,711,02 - 2,890,04CV risk factors (at least 1)0,920,41 - 2,030,830,870,51 - 1,490,62WBCPV ≥ 10,175.109/L ET ≥ 9,630.109/L1,090,57 - 2,080,801,410,89 -2,260,15 Disclosures No relevant conflicts of interest to declare.

Description: The protective effect of higher platelet count at diagnosis of Essential Thrombocythemia (ET) was reported in some papers (Carobbio A. 2011, Palandri F. 2012, Montanaro M., 2014). As at our knowledge, there is no study specifically addressing this point; in this retrospective analysis we have examined 1201 ET patients (pts) followed in 11 Hematological centers of our region from 1/1978 to 12/2010. The diagnosis of ET was made with PVSG, WHO 2001 and WHO 2008 criteria, respectively, according to the period of 1st observation. The main features of our cohort were as follows: median age 62,9 yrs (19-96), male/female 435/766 (36.2%/63.8%), median WBC count 8,8 x 106/L (1.2-57.7), median Hb level 14.0 g/dl (6.0-20.5), median platelet count 813 x 106/L (457-3582), JAK-2V617F mutation in 498/834 performed pts (59,7 %) with a median allele burden of 19.6% (0.2-99.9%), spleen enlargement in 226 pts (18.7%), previous thrombosis in 17.9% of pts (arterial 14.1%, venous 3.8%). The median follow-up of the entire cohort was 7.75 yrs. Thrombosis-free survival curves were plotted according to Kaplan-Meier method and independent risk factors were identified with the Cox proportional-hazards method. At the multivariate analysis, negative prognostic factors for TFS resulted: previous thrombotic events (p= 0.012), age ≥60 yrs (p= 0.008) and spleen enlargement (p= 0.039): on the contrary, platelet count ≥ 944.109/L resulted a protective factor for TFS [p= 0.031 with an HR 0,57 (C.I. 95% 0,35-0,95)]. Receiver operating characteristic (ROC) analyses based on thrombotic events during follow-up were used to identify the baseline platelet count of 944 x 109/L as the best threshold for predicting thrombotic events. Thrombotic events according to this cutoff were 40/384 (10.3%) in pts with platelet count ≥ 944 x 109/L and 109/817 (13.3%) in pts with platelet count 〈 944 x 109/L. The sites of thrombosis are reported in the table. A comparison of the main features in these two populations showed that pts with PLT count 〈 944 x 109/L were older (median age 60.4 yrs vs 57.1 yrs, p= 0.016), had a lower median WBC count (8.8 x 109/L vs 10.6 x 109/L, p〈 0.0001), an higher median Hb level (14.1 g/dL vs 13.6 g/dL, p〈 0.0001) and an higher rate of JAK-2V617F mutation (67.2% vs 41.6%, p〈 0.0001); no differences were observed between the two groups as to thrombotic events before diagnosis, spleen enlargement and cardiovascular risk factor (p=NS). As to the treatment, both groups resulted equally treated with anti-aggregant agents (84,6% vs 87,4%, p= 0,76) while in pts with platelet count

Description: Abstract 2818 Poster Board II-794 INTRODUCTION: Bisphosphonate (BSFs) are an effective drug which have been mainly used in oncology for the treatment of solid tumour with bone metastasis, as well as for haematologic disease such as multiple myeloma (MM) and Waldenstrom's Macroglobulinemia (WM), but also prescribed in non neoplastic disease such osteoporosis and Paget's disease. As rare complications related to prolonged treatment with BSFs, an osteonecrosis of the jaw (BRONJ) in neoplastic and non neoplastic diseases is reported with an incidence between 2 and 15% as described in different casitics. The aim of this retrospective multicentric study is to describe the clinical aspects and the evolution of the osteo-necrotic lesions in a long term group of MM patients treated with BSFs. MATERIAL AND METHODS: We studied retrospectively 55 patients (pts) with MM or WM who developed BRONJ followed from January 2003 to January 2009 in different haematological departments. Median age was 72 years (range 56-95), male 16/ 39 female. Immunoglobulin isotype was: 25 pts IgG-κ; 6 pts IgG-α, 12 pts IgA-κ; 3 pts IgA-γ, 5 pts IgM-κ (WM), 3 pts MM light chain κ and 1 pt MM light chain γ. All patients have been treated with BSFs for bone lesions and/or factures: Pamidronate was used in 1 pt (1,8 %), Zolendronic acid in 36 pts (65,5 %), Pamidronate followed by zolendronate in 18 pts (32,7 %). The average dose of Pamidronate was 2.022 mg (range 90-6.750 mg) and of zoledronate was 84 mg (range 4-256 mg). Anatomic localisation of the BRONJ was: mandible 29 pts (52,7%); maxilla 22 pts (40%); mandible/maxilla 4 cases (7,3 %). The most common trigger for BRONJ was dentoalveolar surgery, including extractions (43 cases-78,4%), dental implant placement (3 patients-5,4%), periodontal disease (5 cases-9 %), and in 3 patients with dental prothesis (5,4%); only 1 patient (1,8%) developed BRONJ spontaneously. All patients stopped bsf therapy after BRONJ diagnosis. RESULTS: After a median observation of 26 months (range 1-110 months) no death for BRONJ complication was reported. All patients were treated with conservative treatment such as antibiotic therapy. In 18 patients (32,7%) antibiotic therapy was the only treatment used. Six patients (10,9%) received antibiotic associated with surgical debridement of necrotic bone. Sixteen patients (29%) were treated with antibiotic therapy in combination with ozonotherapy and curettage; twelve patients (21, 8%) required sequestrectomy in association with antibiotic and oxygen/hyperbaric therapy. Three patients (5, 4%) refused any therapy. Among the evaluable patients (53) complete response (CR) was observed in 20 cases (37.75%); partial response (PR) in 21 patients (39.6%) with improving as secondary infection and pain; the clinical finding was unchanged (SD) in 9 patients (16,3%) and 3 patients (5,4%) developed a worsening of the osteonecrosis (PD). CONCLUSIONS: In the unvariate analysis association of surgical treatment with antibiotic therapy, is more effective to eradicate the necrotic bone than antibiotic treatment alone (p=

Description: Abstract 3077 Hydroxyurea (HU) is still the cornerstone in the cytoreductive treatment of Myeloproliferative Neoplasms (MPN); however, skin toxicity has been reported as a limiting toxicity during HU treatment in many case reports. To evaluate the real incidence and the clinical features of such complication, among 942 patients with MPN consecutively diagnosed at 3 Centers in Rome, we revised 587 patients (M/F 263/324, median age 64.2 years, IR 53.7 – 72.7) who received HU treatment during the course of disease. There were 304 patients with Essential Thrombocythemia (ET), 202 with Polycythemia Vera (PV), 68 with Primary Myelofibrosis (PMF) and 13 with unclassifiable Chronic Myeloproliferative Disorders (CMPD-u); 496 patients (84.5%) received HU as 1st line treatment while 91 (15.5%) as 2nd or 3rd line treatment. On the whole, 50 patients (8.5%) had a skin toxicity during HU treatment, after a median period from HU start of 32.1 months (IR 10.5 – 74.6) and a mean HU dosage of 1085 mg (+/&− 390 mg); as to the different types of toxicity, 31 patients (62%) had a painful ulcerative skin toxicity (UST) that in 25/31 was located in the perimalleolar area, 9 patients (18%) had oral aphthous ulcers and 10 patients (20%) a non ulcerative skin toxicity (NUST) with erythema and skin infiltration (diffuse in 2 patients, localized to the head or to the extremities in 5 and 3 patients, respectively). Among these different types of skin toxicity there was no difference as to mean HU dosage; however, oral aphthous ulcers were an early toxicity (median time from HU start 1.9 months, IR 1.6 – 2.7) while UST and NUST were late complications (median time from HU start 35.1 months, IR 22.9 – 81.7, and 36.1 months, IR 17.0 – 64.5, respectively). When the skin toxicity occurred, HU treatment was continued at the same dosage in 5 patients (10%), was reduced in 12 patients (24%) and temporarily interrupted in 7 patients (14%); the remaining 26 patients (52%) needed a permanent drug discontinuation. After a median period of 4.3 months (IR 2.4 – 9.0) from the onset of the skin toxicity, 38 patients (76%) had a complete resolution and 8 patients (24%) an improvement without complete resolution; oral aphthous ulcers and NUST had a shorter median time of resolution compared to UST (1.8 months, IR 0.7 – 6.6, and 3.1 months, IR 3.0 – 8.4, versus 6.0 months, IR 3.1 – 16.5, respectively). In conclusion, skin toxicity during HU treatment is more common than expected, with about 9% of incidence and can have different clinical features; moreover, it often need a permanent drug discontinuation and in about 25% of patients there is only a partial resolution. Thus, further studies are warranted to highlight pathogenesis, which could be different in the various types of toxicity, and individual predisposing factors. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 5062 Thrombotic events occurring before or at diagnosis of Essential Thrombocythemia (ET) are a worldwide recognized prognostic factor for the incidence of thrombosis during the follow-up of ET patients: however, these previous thrombotic events have been considered on the whole in the vast majority of studies, without further characterization. Among 1063 ET patients collected in the retrospective database of the “Gruppo Laziale SMPC Ph-”, we revised 186 cases with a previous thrombosis and a known data of occurrence, to evaluate the role of the interval from previous thrombotic episode and the diagnosis of ET. In 95 patients (51. 1%) previous thrombotic event occurred 〈 24 months before diagnosis of ET (group A) while in 91 patients (48. 9%) thrombosis occurred ≥ 24 months before diagnosis of ET (group B). Clinical features of patients at diagnosis are shown in the Table: GROUP A GROUP B p Gender (M/F) 40/55 42/49 0.636 Median age (yrs) (Interquartile range) (IR) 64.1 (52.7–71.8) 70.9 (61.0 – 78.0) 0.001 Hb median (g/dl) (IR) 13.9 (12.5 – 14.7) 14.2 (13.0 – 15.2) 0.136 PLT median (x 109/l) (IR) 800 (669 – 1066) 778 (652 – 926) 0.453 WBC median (x 109/l) (IR) 9.2 (7.8 – 11.3) 8.6 (7.1 – 10.8) 0.121 Median interval diagnosis – CHT (mos) (IR) 0.9 (0 – 7.0) 1.7 (0.4 – 5.6) 0.194 *CV risk factors (n°/%): 0.454     0 20 (21.0) 17 (18.6)     1 42 (44.2) 44 (48.3)     ≥ 2 33 (34.8) 30 (33.1) Type of previous thrombosis (n°/%): 0.873     Arterial 78 (82.1) 67 (73.6)     Venous 17 (17.9) 24 (26.4) * Cardiovascular (CV) risk factors at diagnosis were considered the presence of arterial hypertension, diabetes, smoking attitude, and hypercholesterolemia. In the group A, 9 out 95 patients (9. 4%) reported thrombotic episodes (5 arterial and 4 venous) during follow-up compared to 23 out 91 patients (25. 2%) (13 arterial and 10 venous) in the group B (p=0. 004). Consequently, patients of group B had a significantly higher cumulative risk of thrombosis compared to patients of group A (p=0. 0029, CI95% 1. 5 – 6. 1, RR 3. 04). In addition, it is worth of note that there was no difference in the cumulative risk of thrombosis between the patients of group A and the 877 patients without previous thrombotic events (p=0. 303, CI95% 0. 64 – 3. 21, RR 1. 24) In conclusion, the prognostic role of a previous thrombotic event in ET patients seems to be related not to the occurrence per se of the event but mainly to the interval between the event and the diagnosis of ET. Disclosures: Tafuri: Sigma Tau Pharmaceuticals: Research Funding.

Description: To evaluate the prognosis of patients with Essential Thrombocythemia (ET) in the first decade of the century we assessed retrospectively the thrombosis free survival (TFS) and the overall survival (OS) of the patients diagnosed from 01/01/2000 to 31/12/2009 and collected in the database of our group. The diagnosis of ET was performed with PVSG, WHO 2001 or WHO 2008 criteria, according to the period of the first observation. The whole population of 757 patients was then divided in two groups: the first (group I) with the diagnosis performed between 01/01/2000 to 31/12/2005 (334 patients) with a median follow-up of 111,9 months, the second (group II) diagnosed between 01/01/2006 to 31/12/2009 (385 patients) with a median follow-up of 58,2 months. The main clinical features of the two groups of patients are reported in the Table 1. No difference was observed between the two groups as to age, gender, platelet and WBC count, Hb level, Cardio-Vascular Risk Factors (CVRF), spleen enlargement and occurrence of previous thrombotic events. The frequency of the JAK-2 V617F mutation resulted significantly different (49.1% vs 68.4%) but in the group I the search of the mutation was never performed at the diagnosis. The TFS and OS were calculated from the date of diagnosis to the date of any appropriate event or to the date of last follow-up with Kaplan-Meier product limit method; the comparison of proportions and median values was computed with the Chi-squared and the Mann-Withney tests, as indicated. No significant difference emerged neither for TFS (p= 0,09, HR 1,42, 95% C.I. 0.89-2.30) nor for OS (p= 0,15, HR 1,34, 95% C.I. 0,87-2,06). We also considered the type of treatment used in the two groups to assess the potential link between the therapy and TFS or OS. No difference emerged between the two groups as to anti-aggregating treatment (mainly ASA), equally utilized in both groups [287/369, 77,8%, and 330/383, 78,3%, respectively (p = 0,95)]. As for the cyto-reductive therapy, Hydroxyurea was used in 74.8% vs 67.9% (p= 0.60) and alkylating agents in 1.9% vs 2.1% (p= 0.85), whereas Anagrelide was used in 10,6% vs 3,9% (p= 0,001) and Interferon in 9,5% vs 5,2% (p= 0,037), respectively. This more frequent use of Anagrelide and Interferon in the first group (2000-2005) did not modify TFS and OS of the patients. In conclusion, no improvement was observed in the prognosis of ET patients in the recent years: thus, new efforts to identify patients at risk and the introduction of new drugs as JAK-2 inhibitors are warranted to improve the prognosis of these patients. Table Table. Disclosures Breccia: Bristol Myers Squibb: Honoraria; Pfizer: Honoraria; Novartis: Consultancy, Honoraria; Celgene: Honoraria; Ariad: Honoraria. Cimino:Celgene: Honoraria; Bristol-Mayer: Honoraria. Lo Coco:Pfizer: Consultancy; Baxalta: Consultancy; Novartis: Consultancy; Lundbeck: Honoraria, Speakers Bureau; Teva: Consultancy, Honoraria, Speakers Bureau. Latagliata:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria; Shire: Honoraria.