Gangat, Naseema

Abstract Background: Acute myeloid leukemia (AML) is an aggressive blood cancer with a wide range of response and relapse rates using standard chemotherapy combining anthracycline plus cytarabine (7+3). The stem cell receptor tyrosine kinase KIT is expressed on more than 10% of blasts in 95% of relapsed AML cases and mediates leukemic proliferation and has anti-apoptotic effects (Domen and Weissman 2000). AML with high KIT expression is associated with poorer outcome (Del Poeta, Venditti et al 2003). Goals: To study the efficacy and safety of combination 7+3 and nilotinib in patients (pts) with AML and KIT expression. Primary goal is to determine the complete response (CR) rate; while secondary goals include 2-year overall survival (OS) and disease free survival (DFS) in addition to safety. Methods: A single arm, Phase II study, enrolled pts at Mayo Clinic (MN and AZ). Appropriate IRB was obtained and study was registered (NCT 01806571). Pts were enrolled if they were newly diagnosed with AML with KIT (CD117) expression of ≥ 20% on myeloblasts by flow cytometry. KIT mutations were allowed. Nilotinib 300 mg twice daily was given on days 4-14 of induction and consolidation; and continuous daily maintenance therapy for up to 2 years. Cytarabine 100 mg/m2/day continuous IV x7 days plus daunorubicin 60 mg/m2 IV daily x3 days were used for induction, while consolidation used standard cytarabine 3 gm/m2 twice daily days 1, 3, 5 for a total of 4 cycles. This is a Simon 1-stage design with a safety analysis after enrolling 12 pts, and an interim analysis after enrolling 18 out of 43 pts (Al-Kali, ASH 2015) recommended to continue study accrual. Results: i)- Demographics: Thirty four pts were enrolled from July 2013 to June 2017. Median age was 59 years (range 24-69) with 71% being male. Median laboratory findings include hemoglobin of 8.8 gm/dL, platelets of 56 x109/L, white blood count of 3.3 x109/L (0.4-125), and peripheral blood blasts 17 %(0-94%). Cytogenetics were normal in 43% of the pts and favorable cytogenetics were seen in 6%(inv 16). FLT3 gene testing was done on 26 pts and was positive in 13%. KIT gene sequencing (exon 8, 9, 10, 11, 17) revealed pathogenic mutation in 1/28 cases (4%). ii)- Clinical outcome Out of all 34 pts enrolled on the study, 18 (53%) achieved CR (or CR with incomplete platelet recovery) with a median CR duration of 21.8 months. Of 26 evaluable pts, the overall CR rate was 69%. 4 of the 18 pts (22%) who achieved remission needed a second induction. One pt died due to liver failure (had only one dose of nilotinib and toxicity was attributed to daunorubicin). 13 (38%) pts proceeded to allogeneic stem cell transplant (HSCT), 12 of whom are alive and none were able to initiate nilotinib maintenance. Only 6 (1 had HSCT) out of 34 (18%) pts relapsed after achieving CR. Median DFS was 45.8 months, while median OS was 42.4 months. 2-year DFS and OS were 58% and 72%, respectively. iii)- Safety Thirty four pts were evaluated for adverse events (AE). Fourteen pts had G4 non-hematological AEs, including fourteen G4 AEs related to infection, 2 with electrolyte imbalances, 1 heart failure, 1 elevated bilirubin, 1 elevated lipase, and 1 jejunal hemorrhage. One patient had G5 liver failure. Most common (>20%) G3 non-hematological AEs were febrile neutropenia (56%), hypophosphatemia (21%), elevated ALT (21%) and hypertension (21%). Conclusion: Combination daunorubicin and cytarabine with nilotinib (DATA) appears to be safe and effective. Final results show an acceptable safety profile with most common AE being infection. Thirty day mortality was low (3%). DATA regimen has comparable CR rates of 53% (intent to treat) and 69% in evaluable pts. Relapse rates were very low at 18% with durable responses and encouraging survival rates. Figure. Figure. Disclosures Al-Kali: Novartis: Research Funding. Tibes:Novartis: Research Funding. Palmer:Novartis: Research Funding.

Abstract Background Familial myeloid neoplasms are rare causes of myeloid malignancies. Over the last few years germline mutations involving RUNX1, JAK2, GATA1, GATA2 and CEBPA genes have been associated with myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN) and acute myeloid leukemia (AML). We carried out this study to describe the spectrum of familial myeloid neoplasms seen at our institution. Methods After due IRB approval, the myeloid neoplasms data base (1990-2012) at the Mayo Clinic in Minnesota was queried for patients presenting with, or having a strong family history of myeloid neoplasms. Selective sequencing of germline DNA was done in appropriate patients. Germline mutations that were screened for included; RUNX1, JAK2, GATA1, GATA2 and CEBPA. In one family with none of the aforementioned gene mutations, exome sequencing was performed. Families with chromosomal breakage and primary telomere disorders were excluded. All patients had bone marrow and cytogenetic studies at diagnosis. Results We identified six families with familial myeloid neoplasms (table one). There were two with germline GATA2 mutations (no.1 and 2); one with a novel c1339A>C, pS447R, non-zinc finger gene abnormality. In this family nine members have developed MDS/AML. All members had profound B/NK cell deficiency, viral warts and one member had primary lymphedema (Embergers syndrome). Three of the 6 seen at the clinic have successfully undergone allo- SCT. The second GATA2 mutated family had a less extensive history of myeloid neoplasms. There was one patient (no.5) who presented with long standing thrombocytopenia, clinically diagnosed as ITP. She eventually developed MDS with trisomy 8. She had three first degree relatives with myeloid neoplasms. Germline sequencing identified a RUNX1 mutation. Platelet electron microscopy identified characteristic ultrastructural changes. There was one family (no.4) with a germline JAK2V617F mutation. The propositus was diagnosed to have primary myelofibrosis and then demonstrated clonal evolution to a concomitant BCR-ABL1 p190 driven chronic myeloid leukemia. His sister and mother have essential thrombocytosis (ET) and his brother has a detectable JAK2 mutation (no evidence for disease). The patient has successfully undergone an allo-SCT. The patient with a GATA1 mutation (no.3) presented with congenital anemia and had craniofacial anomaly, atrial septal defect and developmental delays. Red cell and platelet ultrastructural abnormalities lead to the diagnosis with an additional family member having chronic anemia and suspected MDS. One family (no.6) presented with seven first degree relatives affected by MDS/AML. Germline sequencing for the aforementioned genes was negative. Exome sequencing has been performed and results should be available at the time of the meeting. The prepositus has successfully undergone allo-SCT. Conclusion Familial myeloid neoplasms are uncommon but warrant early recognition. Clues to diagnosis include strong family history, associated primary immunodeficiency states, morphological/skeletal abnormalities and platelet ultrastructural defects (RUNX1, GATA2, and GATA1). Exome and whole genome sequencing is an exciting prospect for further discoveries. Disclosures: No relevant conflicts of interest to declare.

Abstract Background : Pre-treatment determinants of survival in adult acute myeloid leukemia (AML) include performance status, age, karyotype, the distinction between primary and non-primary AML and FLT3-ITD/NPM1 mutational status. Current literature on AML natural history and risk factors is often based on information derived from stringent protocol studies. In the current series of 1,123 adult patients seen at the Mayo Clinic between 2004 and 2017, we examined long-term survival specified by a number of primarily established risk factors. Methods: Diagnosis of AML and its sub-classification was according to World Health Organization criteria. Study subjects were recruited from the Mayo Clinic AML database. Conventional response criteria were used for CR and CRi assignment; the latter met all criteria for CR with the exception of platelet count <100 x 109/l or absolute neutrophil cunt <1 x 109/l. Standard statistical methods were used for analysis of overall survival, calculated from the initial diagnosis of AML to date of death or last follow-up; analyses were performed both in the absence and in the presence of censoring of survival at time of allogenic stem cell transplant (ASCT). The JMP® Pro 13.0.0 software from SAS Institute, Cary, NC, USA, was used for all calculations. Results: 1,123 adult patients (median age 65 years, range 18-94; 61% males) with non-APL AML were considered; 61% were age >60 years. 351 (31%) patients were seen between 2004 and 2009 and 772 (69%) between 2010 and 2017. AML subcategories were primary (56%), post-myelodysplastic syndromes (post-MDS; 24%), therapy-related (10%), post-myeloproliferative neoplasm (post-MPN; 8%) and post-MDS/MPN (3%). Cytogenetic risk distribution, according to the European LeukemiaNet classification, was favorable in 47 (4%), intermediate in 650 (58%) and adverse risk in 426 (38%) patients. FLT3, NPM1 and CEBPA mutation information was available in 462 (24% mutated), 393 (27% mutated) and 228 (11% mutated) patients, respectively. Treatment included intensive chemotherapy (IC) in 766 (68%) patients, less aggressive chemotherapy, including the use of hypomethylating agents in 144 (13%) and supportive care alone in 213 (19%) patients. ASCT was utilized in 258 (23%) cases, almost all performed after achieving CR/CRi. Complete remission (CR) and CR with incomplete count recovery (CRi) were listed in 333 (30%) and 248 (22%) patients, respectively; the corresponding rates in IC-treated patients were 43% and 32%. Almost all cases of CR/CRi occurred in IC-treated patients; 2 (1.4%) CRs were listed for less aggressive chemotherapy. After a median follow-up of 11 months, 798 (71%) deaths were recorded. Median survival for all 1,123 patients was 14 months with 1-, 3- and 5-year survival rates of 54%, 29% and 23%, respectively; a slight but significant (p=0.01) improvement in survival was apparent in more recent years (Figure 1a). Figures 1b, 1c and 1d depict analysis stratified by AML subcategories, treatment received and response obtained, respectively. Similarly, figures 2a, 2b and 2c depict analysis stratified by karyotype, use of ASCT and age. Multivariable analysis of pre-treatment parameters evaluable in all 1,123 patients identified age >60 years (HR 2.2, 1.9-2.6), adverse karyotype (HR 2.9, 1.9-4.9), intermediate-risk karyotype (HR 1.6, 1.02-2.6), post-MPN AML (HR 1.9, 1.5-2.4) and other secondary AML (HR 1.3 (1.1-1.6), as risk factors for shortened survival; the inclusion in the model of FLT3/NPM1 mutational status in 392 informative cases confirmed the adverse prognostic effect of age >60 years (HR 1.8, 1.4-2.5), adverse karyotype (HR 3.7, 1.4-15.3), post-MPN AML (HR 2.8, 1.6-4.6), other secondary AML (HR 1.4, 1.0-1.9) and FLT3+NPM1- (HR 2.8, 1.6-4.9) and FLT3-NPM1- (HR 1.7, 1.2-2.7) profile. Results were unchanged when survival was censored at time of ASCT. Additional prognostic interaction with treatment strategy and ASCT is further elaborated in an accompanying abstract to be presented. Conclusions: The current study, the largest coming from a single institution, provides practically useful information that should assist with patient consultation on AML prognosis and treatment. The study confirms the primary prognostic importance of age, karyotype and FLT3/NPM1 mutational status, in real-life practice. Novel observations included comparable value of CRi vs CR and the particularly worse prognosis associated with post-MPN AML. Disclosures Al-Kali: Novartis: Research Funding.

Abstract Background : Thrombosis is a characteristic feature in essential thrombocythemia (ET) and polycythemia vera (PV). Previous studies had focused on thrombotic events occurring after diagnosis and did not always distinguish between arterial and venous thrombosis. Arterial thrombosis in ET has been associated with age >60 years, JAK2 mutations, leukocyte count >11 x 109/l, history of thrombosis and cardiovascular risk factors, and venous thrombosis with male sex (Blood 2011;117:5857). In the current two-enter study, we looked for associations between both driver and other mutations, with first incidences of arterial and venous thrombosis in ET and PV, analyzed together and separately. Methods : Study patients were recruited from the Mayo Clinic, Rochester, MN, USA and the University of Florence, Florence, Italy, based on availability of next-generation sequencing-derived mutation information. Diagnoses were according to the 2016 World Health Organization criteria (Blood. 2016;127:2391). Conventional statistics was employed to examine significance of associations, with separate analysis of arterial vs venous thrombosis, occurring at any time before or after formal diagnosis of ET or PV. For the purposes of the current study, only first events were considered. Results: 906 molecularly-annotated patients (416 from Mayo and 490 from Florence), including 502 ET and 404 PV cases, were included in the current study. The Mayo/Florence cohorts included 270/232 ET (median age 57/54 years, 60%/59% females) and 146/258 PV (median age 63/58 years, 52%/44% females) patients; median follow-up was 9.9/12.9 years for ET and 10.7/12.4 years for PV. Driver mutation distribution in ET was 55% JAK2, 27% CALR, 5% MPL and 13% triple-negative. Most frequent mutations, other than JAK2/CALR/MPL, were TET2 (14%; 11% in ET and 18% in PV) and ASXL1 (13%; 13% in ET and 13% in PV). 301 (33%) patients experienced first time thrombosis, before or after diagnosis, including 152 (30%) in ET and 149 (37%) in PV (p=0.03); arterial events occurred in 174 (19%) patients, including 96 (19%) in ET and 78 (19%) in PV (p=0.9); venous events occurred in 177 (20%) patients, including 82 (16%) in ET and 95 (24%) in PV (p=0.007). The number of vascular events after diagnosis was 174 (19%) for arterial and 154 (17%) for venous thrombosis, with no significant difference between ET and PV. Associations with arterial thrombosis: In multivariable logistic regression analysis that included both ET and PV (n=906), age >60 years (23% vs 16%; OR, 1.6, 95% CI 1.1-2.2) and absence of ASXL1 and RUNX1 mutations (21% vs 9%; OR 2.6, 95% CI 1.4-4.8) were associated with arterial thrombosis; these associations remained significant (or near significant) when ET and PV were analyzed separately; in addition, JAK2 mutations in ET displayed borderline significance (p=0.05). Overall incidence of arterial events in ET was estimated at 27% in the presence of all three risk factors (i.e. older age, presence of JAK2 mutations and absence of ASXL1/RUNX1 mutations), 21% with two risk factors, 13% with one risk factor and 9% in the absence of all three risk factors (p=0.01). Associations with venous thrombosis: In multivariable analysis, including both ET and PV (n=906), JAK2 mutations (p<0.001), higher leukocyte count (p=0.03) and younger age (p=0.04) were identified as being significant. Analysis of ET patients only (n=502) identified JAK2 mutations (p<0.001; OR 2.4, 95% CI 1.4-4.1), absence of SRSF2 mutations (p=0.03) and younger age (p=0.04) as independent risk factors and in PV patients (n=404), higher leukocyte count (p=0.06). Prognostic interaction between JAK2 mutations and age: In ET, the overall frequency of venous events was 27% for young patients with JAK2 mutations vs 13% for older JAK2 mutated cases vs 10% for JAK2 unmutated young patients vs 13% for JAK2 unmutated older patients (p<0.001). The corresponding percentages for arterial events were 20%, 24%, 14% and 19%, respectively (p=0.1). Conclusions: JAK2 mutations contribute to the risk of both venous (younger patients) and arterial (young and older patients) thrombosis, in an age-dependent manner; the association with venous thrombosis might explain the higher incidence of venous thrombosis in PV, compared to ET. Additional studies are required to confirm the observed lower risk of thrombosis in patients with ASXL1, RUNX1 and SRSF2 mutations and provide insight into the underlying biological explanation. Disclosures No relevant conflicts of interest to declare.

Abstract Background: While several population-based studies have reported on adverse outcomes and life expectancy in myeloproliferative neoplasms (MPN) (JCO. 2015;33:2288; AJH. 1999;61:10; Leukemia. 2013;27:1874; JCO. 2012;30:2995), large-scale studies reporting mature data have been rare and important questions remain unanswered. The current study documents the Mayo Clinic (MC) decades-long experience with over 3,000 consecutive MPN patients including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) with the majority of patients followed until death. Herein, we provide mature, and importantly, risk-stratified survival data and disease complication estimates. Methods: Study patients were recruited from MC, Rochester, MN, USA between 10/27/1967 and 12/29/2017. All MPN diagnoses and documentation of fibrotic/leukemic transformations were in accordance with the 2016 World Health Organization criteria (Blood. 2016;127:2391). Clinical and laboratory data were abstracted from medical records. Risk-stratification used conventional risk models considering age, leukocytes, and venous thrombosis for PV (Leukemia. 2013;27:1874), international prognostic score for ET (Blood. 2012;120:1197), and dynamic international prognostic scoring system for PMF (Blood. 2010;115:1703). Statistical analyses were based on parameters obtained at the time of referral to MC which, in the majority of cases, coincided with or was within 1 year of diagnosis. All patients were followed from diagnosis until death or date of last follow-up/contact. Recipients of allogeneic stem cell transplants were censored at the time of transplant. Standard statistical methods and time-to-event curves prepared using the Kaplan-Meier method were used to compare MPN subgroups. Survival data for low-risk ET/PV were compared with age- and sex-matched controls from Olmstead County, MN, USA. JMP® Pro 13.0.0 software (SAS Institute, Cary, NC, USA) was used for all analyses. Results: 3,023 consecutive patients (median age 62 years, range 18-96; 51% males) were considered, including 89% diagnosed within the year: 665 PV, 1076 ET and 1282 PMF. Conventional risk stratification in 2925 evaluable patients revealed low, intermediate, and high-risk status in 26%, 29%, and 45% of PV and 30%, 42%, and 28% of ET patients, respectively, while PMF cases were attributed low (14%), intermediate-1 (38%) -2 (40%) and high (8%) risk (Table 1). After a median follow-up of 8.2 years for PV (range 0-39), 9.9 for ET (range 0-47), and 3.2 for PMF (range 0-31), 1631 (54%) deaths, 183 (6%) leukemic transformations, 244 (14%) fibrotic progressions, and 516 (17%) thrombotic events were recorded (Table 1). Median overall survival (OS) was 18 years for ET, 15 for PV and 4.4 for PMF (p<0.05 for all inter-group comparisons) (Figure 1A). Leukemia-free survival was similar for ET and PV (p=0.22) and significantly worse for PMF (p<0.001) (Figure 1B). PV, compared to ET, was associated with higher risk of fibrotic progression (p<0.001) (Figure 1C). Thrombosis risk after diagnosis was highest in PV and lowest in PMF (p=0.002 for PV vs ET; 0.56 for ET vs PMF; and 0.001 for PV vs PMF) (Figure 1D). Following risk stratification, median OS in low-risk ET (28 years) and low-risk PV (27 years) were superimposed (p=0.89) (Figure 2). Similarly, intermediate or high-risk PV and ET patients had comparable OS within each risk strata (p=0.23 and 0.11, respectively). Low-risk PMF survival was analogous to that of intermediate-risk PV (p=0.06). All other risk-stratified categories disclosed significantly different inter- and intra-group survival patterns (p<0.001) (Figure 2). Despite their categorization as favorable-risk disease, both low-risk ET and low-risk PV displayed excess mortality relative to age- and sex-matched controls with median survival of 26.7 and 28.1 years respectively, compared to the expected 37.5 and 39.2 years (p<0.001) (Figure 3). Conclusions: The current study provides large-scale and uniquely mature survival and outcomes data in MPN and highlights MPN subgroup risk categorization as cardinal in appraising disease natural history. Interestingly, OS was only marginally better in ET, compared to PV, while the latter clearly displayed a higher risk of thrombosis and fibrotic progression. Moreover, data disclosed shortened life expectancy relative to matched controls even in MPN with favorable risk attribution. Disclosures Busque: BMS: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Paladin: Consultancy.

Abstract Abstract 2806 Background: A high degree of prognostic certainty is required to recommend or discourage high risk treatment procedures in primary myelofibrosis (PMF). The Dynamic International Prognostic Scoring System (DIPSS-plus) uses eight risk factors to predict overall survival (OS) in PMF: unfavorable karyotype, peripheral blood (PB) blast count ≥1%, platelet count <100 × 109/L, white blood cell count (WBC) >25 × 109/L, hemoglobin level <10 g/dL, red blood cell transfusion need, constitutional symptoms, and age >65 years (Gangat et al. JCO 2011;29 :392). The presence of four or more of these risk factors defines high-risk disease. purpose: The purpose of the current study was to enhance the prognostic weight of some of the DIPSS-plus risk factors with the intent to identify one or two parameters that can reliably predict death in the first two years of disease. Methods: An updated Mayo Clinic database of 884 karyotypically-annotated patients with PMF was used. Calculations of 2-year mortality rates and variables considered for prognostic value were from time of referral to the Mayo Clinic. Cytogenetic risk categorization per DIPSS-plus was further refined to capture additional prognostic information from monosomal karyotype (MK) (Vaidya et al. Blood 2011;117 :5612) and inv(3)/i(17q) abnormalities (Caramazza et al. Leukemia 2011;25 :82). Receiver operating characteristic (ROC) analysis was employed to define best discriminant levels. Results: To date, 564 (64%) deaths have been documented. Each one of the aforementioned DIPSS-plus risk factors was associated with a 2-year mortality rate that ranged from 42% (PB blast count ≥1%) to 60% (unfavorable karyotype). High-risk disease per DIPSS-plus was associated with 57% two-year mortality. The only risk factors that were associated with >80% two-year mortality were MK (n =19) and inv(3)/i(17q) abnormalities (n =8) and both were associated with significantly worse survival, compared to other unfavorable karyotype (n =102): HR (95% CI) of 5.1 (3.1−8.4) and 3.9 (1.7−8.8), respectively. ROC analysis identified PB blast counts of 2% and 9% (AUC 0.62) and WBC of 43 × 109/L (AUC 0.66) as best discriminant levels for predicting 2-year mortality; OS was significantly worse in the presence of PB blast >9% (HR 4.1, 95% CI 2.8–6.1) vs. 2% to 9% (HR 1.8, 95% CI 1.5–2.2) vs. <2%; the corresponding 2-year mortality rates were 73%, 46% and 25%. OS was also significantly worse in the presence of WBC ≥40 × 109/L (HR 2.8, 95% CI 2.2–3.6) vs. 26–39 × 109/L (HR 1.6, 95% CI, 1.2–2.1) vs. <26 × 109/L; the corresponding 2-year mortality rates were 63%, 42% and 28%. Two-year mortality rates exceeded 80% in the presence of any two of the following: PB blast count >9%, WBC ≥40 × 109/L or unfavorable karyotype other than MK or inv(3)/i(17q). Conclusions: A greater than 80% 2-year mortality in PMF is predicted by the presence of MK, inv(3)/i(17q) abnormalities, or any two of the following: PB blast >9%, WBC ≥40 × 109/L, other unfavorable karyotype. Such patients and those with high DIPSS-plus risk should be referred to allogenic stem cell transplantation earlier than later. Disclosures: No relevant conflicts of interest to declare.

Abstract Background The management of extramedullary relapse (EM) of acute myeloid leukemia (AML) after allogeneic stem cell transplant (allo-SCT) is not standardized. We present a single institution experience, describing the risk factors, outcomes and management of EM leukemia relapse in AML patients who underwent allo-SCT. Methods After due IRB approval, 351 patients with AML who underwent allo-SCT at Mayo Clinic, Rochester, from 1985 through 2012, were evaluated for EM relapse. All patients had BM biopsies and cytogenetic studies at diagnosis and at relapse. Extramedullary relapse was identified by clinical exams and radiological methods and confirmed where possible by biopsies and cerebrospinal analysis (CSF). Clinical, pathological and transplant related data was retrospectively abstracted. Results Of 351 patients, 26 (7%) had EM involvement at initial diagnosis (17 CNS, 9 non-CNS, 3 both). Forty-four (13%) patients had CNS disease detected prior to allo-SCT. Of these, 17 (39%) were detected at AML diagnosis due to clinical signs/symptoms, 11 (25%) were detected to have CNS involvement at the time of AML relapse and 16 (36%) were asymptomatic; diagnosed on routine pre transplant CSF studies. All patients with pretransplant EM disease received appropriate therapy prior to undergoing transplantation. After allo-SCT, 21 (6%; 12 male) of 351 patients sustained an EM relapse (11 CNS alone, 9 non-CNS, 1 both). The non-CNS EM relapse sites were cutaneous, skeletal, renal, breast, testicular, gastrointestinal tract and soft tissue. In 12 patients with CNS relapse, 8 (68%) presented with localizing signs and symptoms and 4 were asymptomatic. The median age at EM relapse was 42 years (range; 2 - 61 years) and the median time to EM relapse was 443 days (range; 90- 6069 days). Salvage therapy offered in 18 patients included, intrathecal chemotherapy (IT) alone in 2, IT + systemic chemotherapy (CTX) in 2, allo-SCT in 1, CTX alone in 6, IT + radiation therapy (XRT) in 1, CTX, IT and XRT in 1, and CTX + XRT in 5 patients, respectively. Three patients were ineligible for further therapy. Median survival after EM relapse was 136 days (18 – 819, days), with 4 patients alive at last followup. At the time of AML diagnosis; 6 (29%) of 21 patients had EM involvement (2 breast, 1 lymph node, 1 CNS and lymph node, 1 cutaneous), 8 (38%) patients had a monocytic differentiation (AML-M4/M5) and 6 of 9 tested, had CD56 expression. Three (14%), 8 (38%) and 10 (48%) patients were risk stratified based on cytogenetic and molecular status (FLT3/NPM1) into favorable, intermediate and high risk, respectively. Subsequently, all 21 patients underwent allo-SCT with 14 patients undergoing matched related donor (MRD) transplants. The transplant conditioning was myeloablative in 16 (76%) patients, of which 11 (69%) received total body irradiation (TBI). Grade II-IV acute graft versus host disease (GVHD) was noted in 11 (52%) patients, while chronic GVHD was noted in 8 (38). On univariate analysis, factors associated with shortened survival after EM relapse included; high risk karyotype at diagnosis (p=0.009), concurrent bone marrow involvement with EM relapse (p=0.01) and reduced intensity conditioning (RIC) (p=0.04). Importantly, CD56 expression (p=0.27), CNS involvement at diagnosis (p=0.76), and chronic GVHD (p=0.383) were not prognostic. On a multivariate analysis, high risk karyotype (p=0.04) and concurrent bone marrow involvement (p=0.04) retained their negative prognostic value. Conclusions Although uncommon, EM relapse after allo-SCT for AML is associated with poor outcomes. Pretransplant CSF screening identifies a significant number of asymptomatic patients with CNS disease. High risk karyotype at diagnosis and concurrent BM involvement with EM relapse are poor prognosticators. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 5148 INTRODUCTION. Patients presenting with a clinical picture of essential thrombocythemia (ET) can actually have an early/prefibrotic myelofibrosis (PMF), according to current WHO criteria, in about 18% of cases. Laboratory tests which are significantly different in early/prefibrotic PMF as compared with histologically confirmed ET (WHO-ET) include decreased gender-matched hemoglobin (Hb), increased white blood cell (WBC), platelet (PLT) counts and lactate dehydrogenase (LDH) values. AIM. To evaluate sensitivity (SE) and specificity (SP) of blood cell counts and LDH, at presentation, for the diagnosis of early/prefibrotic PMF vs. WHO-ET. METHODS. Five hundred thirty-six cases (50%) who had complete laboratory data measured at diagnosis constituted the exploratory set of our study and were derived from an international ET database. The discriminatory ability of Hb, WBC, PLT and LDH in correctly classifying patients in the early/prefibrotic PMF or WHO-ET groups was initially tested by plotting their Receiving Operating Characteristic (ROC) curves and comparing the relative Areas Under the Curve (AUC) with the value of 0.50 (which stands for the completely useless of the test). Three parameters with statistically significant discriminatory power were chosen (Hb, WBC and LDH) and thresholds searched in order to guarantee at least 90% of SE or SP. Finally, a diagnostic algorithm was designed. The validation set of this analysis was constituted by 321 patients with WHO-ET (n=62) or early/prefibrotic PMF (n=259) diagnosed by the same pathologist who confirmed the training set cohort and collected in the Institute for Pathology, University of Cologne, Germany. SE and SP for the same parameters and thresholds as well as the final diagnostic algorithm were applied to this set of patients to demonstrate the results' reproducibility. RESULTS. Sensitivity and specificity to recognize early/prefibrotic PFM have been evaluated by ROC curves. The best performance was found for LDH (AUC = 0.7059). WBC and Hb had super imposable curves, with AUC of 0.6279 and 0.6257, respectively. The worst performance was registered for PLT count: its AUC was only 0.5628, not significantly different from the reference value of 0.50 (p=0.154). Thresholds of Hb, WBC and LDH were searched to achieve at least 90% of SE or SP. HB < 12 g/dL for women or <13 g/dL for men, and WBC >= 13 x109/L had higher SP (92% and 91%, respectively). High SP is highly related to the presence of early/prefibrotic PMF (true positives). On the contrary, LDH < 200 mU/mL and WBC < 7 x109/L had good sensitivity (91% and 94%, respectively). High SE is highly related to the absence of early/prefibrotic PMF (true negatives). By applying these SE and SP values in a step-by-step algorithm, nearly half of patients (48%) could be classified as WHO-ET or early/prefibrotic PMF, assuming at each step a margin of error of less than 10%. For the remaining 50% of patients, laboratory results didn't allow to suspect or exclude the presence of early/prefibrotic PMF. In the validation set of 321 patients classified by WHO 2008 as true ET or early/prefibrotic PMF (Cologne cohort) SP of anemia was 84%, WBC < 7 x109/L or >= 13 x109/L had 91% and 81% of SE and SP, respectively. LDH values < 200 mU/mL had 85% of SE. By applying the same flow-chart, 46% of patients were classified as WHO-ET or early/prefibrotic PMF. CONCLUSIONS. The present study provides clinicians with laboratory parameters that should increase suspicion of early/prefibrotic PMF in a patient with a working clinical diagnosis of ET. In fact, while patients presenting clinically with ET can now be discriminated as true ET or early/prefibrotic PMF by adopting the WHO 2008 criteria that require bone marrow histology, an algorithm including baseline anemia, WBC count and LDH, allows this differentiation in about 50% of patients with a good approximation. However, for a definitive proof, bone marrow histology is still an integral part for final diagnosis. Disclosures: Vannucchi: Novartis: Honoraria.

Abstract Background: In both polycythemia vera (PV) and essential thrombocythemia (ET), aspirin and/or hydroxyurea therapy provide adequate protection from thrombosis but not from disease transformation into acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) or myelofibrosis (MF). In designing clinical trials with new drugs, including the use of small molecule JAK2 inhibitors, in either ET or PV, it is important to identify patients who are at a higher risk of early transformation into AML/MDS/MF as well as those in whom the long-term risk of these complications is too low to justify exposure to experimental drugs with unknown short-term and long-term toxicity profile. Methods: Information on an institutional database of 1061 patients with either PV (n=458) or ET (n=603) was updated in July of 2007. The World Health Organization criteria were used for diagnosis of PV, ET, AML, MDS, and MF. Two different approaches were used to assess both early and overall risk of AML/MDS/MF development in both ET and PV. In the first approach, three distinct groups were delineated and their presenting features compared; group A was comprised of patients who have remained AML/MDS/MF free after a minimum follow-up of 20 years whereas groups B and C included patients who developed either AML/MDS or MF, respectively, in the first decade of their disease. In the second approach, prognostic factors for AML/MDS/MF-free survival were examined among the entire cohort of 1061 patients. Results : In ET, the number of patients that fulfilled the above-mentioned criteria for inclusion in groups A, B, and C were 40, 12, and 8; the three groups displayed significant differences in the prevalence, at diagnosis, of lower than normal hemoglobin level (8% vs. 58% vs. 38%; p=0.0004), male sex (18% vs. 58% vs. 50%; p=0.01), and arterial thrombosis at diagnosis (p=0.03), respectively. However, only the former two remained significant during multivariable analysis that included age as a covariate. In PV, the number of patients in groups A, B, and C were 23, 18, and 12; the only difference between the three groups was the association between group B and leukocytosis (p=0.02). Cox regression analysis of the entire 1061 ET/PV patients cohort, including 65 AML/MDS/MF events in ET and 36 AML/MDS events in PV, confirmed the inferior AML/MDS/MF-free survival in ET associated with lower than normal hemoglobin and AML/MDS-free survival in PV associated with leukocytosis (Figure). Conclusion : The current study identifies PV patients with leukocytosis as being the most appropriate and ET patients without anemia as the least appropriate for consideration of participation in experimental drug treatment trials. Figure Figure Figure Figure

Abstract Background : Current prognostication in primary myelofibrosis (PMF) utilizes international prognostic scoring systems that rely on clinical parameters that are sensitive to day-to-day variations and subjective interpretation. Recent studies in PMF have disclosed important prognostic information attached to additional cytogenetic details (Blood. 2011;118:4595) and somatic mutations, including CALR and ASXL1 (NEJM. 2013;369:2379; Leukemia. 2013;27:1861). Methods : PMF diagnosis and definition of blast transformation (BT) were according to World Health Organization criteria (Blood. 2009;114:937). Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature (Cytogenetic and genome research. 2013. Prepublished on 2013/07/03 as DOI 10.1159/000353118). Previously published methods were used for analyses of CALR, JAK2, MPL and other prognostically-relevant mutations, including ASXL1, SRSF2, EZH2 and IDH(Leukemia. 2014;28:1472). Results : The training set included 964 Mayo Clinic patients (median age 65 years; 62% males) in whom informative karyotype or mutation information was available; cytogenetic information was available in 903 (94%) cases, JAK2/CALR/MPL mutational status in 532 (55%), ASXL1 in 425 (44%), SRSF2 in 434 (45%), IDH1/2 in 376 (39%) and EZH2 in 268 (28%). DIPSS-plus (JCO. 2011;29:392) risk distribution was high in 37% of patients, intermediate-2 in 37%, intermediate-1 in 15% and low in 11%. We used a revised risk stratification for cytogenetics (see accompanying ASH 2014 abstract) to distinguish four distinct cytogenetic risk categories: very high (monosomal karyotype, inv(3), i(17q), -7/7q-, 11q or 12p abnormalities; n=67), high (complex non-monosomal, two abnormalities not included in very high risk category, 5q-, +8, other autosomal trisomies except +9, and other sole abnormalities not included in other risk categories; n=164), intermediate (sole abnormalities of 20q-, 1q+ or any other sole translocation, and -Y or other sex chromosome abnormality; n=133) and low (normal or sole abnormalities of 13q- or +9; n=539). Mutational frequencies were 58% for JAK2, 25% CALR, 7% MPL, 36% ASXL1, 11% SRSF2, 5% IDH1/2 and 6% EZH2. The 131 cases with CALR mutations were further subclassified into two prognostically different groups: type 1/type 1-like (n=110) and type 2/type 2-like (n=21) (see accompanying ASH 2014 abstract). At a median follow-up time of 4.2 years for patients who are alive, 664 (69%) deaths and 70 BT (7%) were recorded. Age-adjusted multivariable analysis that included cytogenetic and mutational risk groups disclosed the following as independent predictors of shortened survival: very high risk karyotype (HR 4.2; 3 points), high risk karyotype (HR 1.9; 1 point), triple-negative (HR 2.8; 2 points), JAK2 (HR 3.1; 2 points), MPL (HR 3.1; 2 points), type 2/type 2-like CALR (HR 3.6; 2 points), ASXL1 (HR 1.9; 1 points) and SRSF2 (HR 1.9; 1 point); EZH2 (p=0.24) and IDH1/2 (p=0.68) and intermediate risk karyotype (p=0.87) were not significant. The above-mentioned significant variables and age demarcated at 60 years (2 points), were subsequently used to develop an HR-derived, genetics-based prognostic scoring system (GPSS) for 369 patients who were fully informative for both karyotype and all significant mutations: low risk (0 points; n=31), intermediate-1 (1 or 2 points; n=90), intermediate-2 (3 or 4 points; n=133) and high (5 or more points; n=115); the corresponding median survivals were >17, 9 (HR 4.7, 95% CI 1.7-13.0), 5 (HR 10.7, 95% CI 3.9-29.3) and 2.2 (HR 29.2, 95% CI 10.6-80.0) years (Figure 1). High risk GPSS was also associated with higher BT rate (HR 7.4, 95% CI 2.1-26.3). The prognostic distinction between high/intermediate-2 and low/intermediate-1 risk GPSS, in terms of both overall (median 5 vs 26.4 years; HR 7.1, 95% CI 3.3-14.9) and leukemia-free survival (median 11.6 years vs not reached; HR 9.4, 95% CI 2.2-41.0) was validated in an independent cohort of 183 patients from the University of Florence (Figure 2). Conclusions : The current study demonstrates the feasibility of genetics-based prognostic models in PMF that rely on objective parameters that are amenable to further refinement as new genetic information becomes available. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.