Citations

Abstract Comparative outcomes of allogeneic hematopoietic cell transplantation (HCT) for BCR-ABL1− myeloproliferative neoplasms (MPNs) in blast phase (MPN-BP) vs de novo acute myeloid leukemia (AML), and AML with prior myelodysplastic syndromes (MDSs; post-MDS AML), are unknown. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we compared HCT outcomes in 177 MPN-BP patients with 4749 patients with de novo AML, and 1104 patients with post-MDS AML, using multivariate regression analysis in 2 separate comparisons. In a multivariate Cox model, no difference in overall survival (OS) or relapse was observed in patients with MPN-BP vs de novo AML with active leukemia at HCT. Patients with MPN-BP in remission had inferior OS in comparison with de novo AML in remission (hazard ratio [HR], 1.40 [95% confidence interval [CI], 1.12-1.76]) due to higher relapse rate (HR, 2.18 [95% CI, 1.69-2.80]). MPN-BP patients had inferior OS (HR, 1.19 [95% CI, 1.00-1.43]) and increased relapse (HR, 1.60 [95% CI, 1.31-1.96]) compared with post-MDS AML. Poor-risk cytogenetics were associated with increased relapse in both comparisons. Peripheral blood grafts were associated with decreased relapse in MPN-BP and post-MDS AML (HR, 0.70 [95% CI, 0.57-0.86]). Nonrelapse mortality (NRM) was similar between MPN-BP vs de novo AML, and MPN-BP vs post-MDS AML. Total-body irradiation–based myeloablative conditioning was associated with higher NRM in both comparisons. Survival of MPN-BP after HCT is inferior to de novo AML in remission and post-MDS AML due to increased relapse. Relapse-prevention strategies are required to optimize HCT outcomes in MPN-BP.

Abstract We examined the risk of subsequent neoplasms (SNs) and late mortality in children and adolescents undergoing allogeneic hematopoietic cell transplantation (HCT) for nonmalignant diseases (NMDs). We included 6028 patients (median age, 6 years; interquartile range, 1-11; range, <1 to 20) from the Center for International Blood and Marrow Transplant Research (1995-2012) registry. Standardized mortality ratios (SMRs) in 2-year survivors and standardized incidence ratios (SIRs) were calculated to compare mortality and SN rates with expected rates in the general population. Median follow-up of survivors was 7.8 years. Diagnoses included severe aplastic anemia (SAA; 24%), Fanconi anemia (FA; 10%), other marrow failure (6%), hemoglobinopathy (15%), immunodeficiency (23%), and metabolic/leukodystrophy syndrome (22%). Ten-year survival was 93% (95% confidence interval [95% CI], 92% to 94%; SMR, 4.2; 95% CI, 3.7-4.8). Seventy-one patients developed SNs (1.2%). Incidence was highest in FA (5.5%), SAA (1.1%), and other marrow failure syndromes (1.7%); for other NMDs, incidence was <1%. Hematologic (27%), oropharyngeal (25%), and skin cancers (13%) were most common. Leukemia risk was highest in the first 5 years posttransplantation; oropharyngeal, skin, liver, and thyroid tumors primarily occurred after 5 years. Despite a low number of SNs, patients had an 11-fold increased SN risk (SIR, 11; 95% CI, 8.9-13.9) compared with the general population. We report excellent long-term survival and low SN incidence in an international cohort of children undergoing HCT for NMDs. The risk of SN development was highest in patients with FA and marrow failure syndromes, highlighting the need for long-term posttransplantation surveillance in this population.

PURPOSE There is no consensus on the best choice of an alternative donor (umbilical cord blood [UCB], haploidentical, one-antigen mismatched [7/8]–bone marrow [BM], or 7/8-peripheral blood [PB]) for hematopoietic cell transplantation (HCT) for patients lacking an HLA-matched related or unrelated donor. METHODS We report composite end points of graft-versus-host disease (GVHD)–free relapse-free survival (GRFS) and chronic GVHD (cGVHD)–free relapse-free survival (CRFS) in 2,198 patients who underwent UCB (n = 838), haploidentical (n = 159), 7/8-BM (n = 241), or 7/8-PB (n = 960) HCT. All groups were divided by myeloablative conditioning (MAC) intensity or reduced intensity conditioning (RIC), except haploidentical group in which most received RIC. To account for multiple testing, P < .0071 in multivariable analysis and P < .00025 in direct pairwise comparisons were considered statistically significant. RESULTS In multivariable analysis, haploidentical group had the best GRFS, CRFS, and overall survival (OS). In the direct pairwise comparison of other groups, among those who received MAC, there was no difference in GRFS or CRFS among UCB, 7/8-BM, and 7/8-PB with serotherapy (alemtuzumab or antithymocyte globulin) groups. In contrast, the 7/8-PB without serotherapy group had significantly inferior GRFS, higher cGVHD, and a trend toward worse CRFS (hazard ratio [HR], 1.38; 95% CI, 1.13 to 1.69; P = .002) than the 7/8-BM group and higher cGVHD and trend toward inferior CRFS (HR, 1.36; 95% CI, 1.14 to 1.63; P = .0006) than the UCB group. Among patients with RIC, all groups had significantly inferior GRFS and CRFS compared with the haploidentical group. CONCLUSION Recognizing the limitations of a registry retrospective analysis and the possibility of center selection bias in choosing donors, our data support the use of UCB, 7/8-BM, or 7/8-PB (with serotherapy) grafts for patients undergoing MAC HCT and haploidentical grafts for patients undergoing RIC HCT. The haploidentical group had the best GRFS, CRFS, and OS of all groups.

Introduction: Approximately two-thirds of patients with primary or post-essential thrombocythemia/polycythemia vera myelofibrosis (MF) have anemia, many of whom require red blood cell (RBC) transfusions. In this heavily transfused population there are severely limited treatment options; effective treatment for anemia in MF is a critically unmet medical need. Luspatercept is a first-in-class erythroid maturation agent which binds to select TGF-β superfamily ligands to reduce aberrant Smad2/3 signaling and enhance late-stage erythropoiesis. Here we report the interim results of the ongoing open-label, phase 2 trial evaluating luspatercept in patients with MF and anemia. Methods: Seventy-four patients with MF and anemia were enrolled, including 41 not receiving concomitant ruxolitinib at study entry who received either no RBC transfusions (n = 20; Cohort 1) or 2-4 RBC U/28 d in the 12 wks prior to treatment (n = 21; Cohort 2). Thirty-three enrolled patients were receiving a stable dose of ruxolitinib for at least 16 wks, of which 14 were not receiving RBC transfusions (Cohort 3A) and 19 were (Cohort 3B). Patients in Cohorts 3A and 3B received a median dose of ruxolitinib of 20 mg/d (range, 5-50 mg/d) for a median of 41 and 43 wks, respectively. Patients received luspatercept every 21 d at a starting dose of 1.0 mg/kg in doses escalating up to 1.75 mg/kg. The primary endpoint in patients not receiving transfusions was a hemoglobin (Hb) increase ≥ 1.5 g/L at every assessment from baseline for ≥ 12 consecutive wks, within the first 24 wks on study. In patients receiving RBC transfusions, the primary endpoint was RBC transfusion-independence (RBC-TI) for ≥ 12 consecutive wks, within the first 24 wks on study. Additional endpoints included proportion of patients achieving mean Hb increase ≥ 1.5 g/dL in Cohorts 1 and 3A, and ≥ 50% decrease in RBC transfusions (minimum 4 RBC U decrease from baseline) in Cohorts 2 and 3B, with both responses lasting ≥ 12 consecutive wks, within 24 wks of study entry. Intent-to-treat (ITT) data were analyzed as of May 10, 2019. Results: Median age was 71 y (range, 50-88 y) and 42 (57%) were male. Median interval from MF diagnosis to study entry was 3.3 y (range, 19 d-13.5 y). Seven patients were Dynamic International Prognostic Scoring System (DIPSS) intermediate-1, 58 were intermediate-2, and 8 were high risk. Median Hb concentration at study entry was 8.8 g/dL (range, 6.7-9.8 g/dL) for Cohort 1 and 8.6 g/dL (range, 6.7-9.1 g/dL) for Cohort 3A. Patients in Cohort 2 received a median of 2.7 RBC U/28 d (range, 1-5 U/28 d) and patients in Cohort 3B received a median of 2.3 RBC U/28 d (range, 2-4 U/28 d). Patients received a median of 8 cycles of luspatercept (range, 1-24 cycles). Efficacy data are displayed in the Table, per ITT data. Two of twenty (10%) and 3/14 (21%) patients in Cohorts 1 and 3A, respectively, achieved an absolute Hb increase ≥ 1.5 g/dL at every measurement from baseline over any consecutive 12 wks. Two of twenty-one (10%) and 6/19 (32%) patients in Cohorts 2 and 3B, respectively, achieved RBC-TI over any consecutive 12 wks. Median duration of Hb response was 20 wks (range, 12-27 wks) in Cohort 1 and 12 wks (range, 12-13 wks) in Cohort 3A. Median duration of RBC-TI was 23 wks (range, 16-31 wks) in Cohort 2 and 32 wks (range, 12-65 wks) in Cohort 3B. Three (15%) and 8 (57%) patients in Cohorts 1 and 3A, respectively, achieved a mean Hb increase of ≥ 1.5 g/dL. Eight (38%) and 10 (53%) patients in Cohorts 2 and 3B, respectively, achieved a ≥ 50% reduction in RBC transfusion burden from baseline. Ruxolitinib exposure remained stable throughout the 24-wk treatment period in both Cohorts 3A and 3B. There was no difference in spleen size between responders and non-responders. Four (5%) patients had grade 3-4 treatment-related adverse events (AEs). There were no treatment-related deaths. Treatment-related AEs occurring in ≥ 3% of patients were hypertension (11%), bone pain (8%), and diarrhea (4%). Seven (9%) patients had ≥ 1 AE resulting in treatment discontinuation; 23 (31%) remain on study. Conclusions: The initial results from this ongoing study suggest clinically significant activity of luspatercept in patients with MF-associated anemia, including those receiving concomitant ruxolitinib. A minority of AEs were grade 3-4 in severity, consistent with previous studies in MDS and beta-thalassemia. Disclosures Gerds: CTI Biopharma: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Pfizer: Consultancy; Imago Biosciences: Research Funding; Roche: Research Funding; Celgene Corporation: Consultancy, Research Funding; Sierra Oncology: Research Funding. Vannucchi:Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; CTI: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Passamonti:Roche: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene Corporation: Consultancy, Speakers Bureau. Kremyanskaya:La Jolla: Consultancy; Incyte, Celgene, Constellation, Protagonist.: Research Funding. Gotlib:Celgene Corporation: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Promedior: Consultancy, Research Funding; Kartos: Consultancy, Honoraria, Research Funding; CTI Biopharma: Research Funding. Ribrag:BMS: Membership on an entity's Board of Directors or advisory committees; AZ: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; argenX: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Infinity: Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy, Membership on an entity's Board of Directors or advisory committees; Epizyme: Honoraria, Research Funding; MSD: Membership on an entity's Board of Directors or advisory committees. Mead:Celgene: Consultancy, Research Funding; CTI: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Other: Travel/accommodation expenses, Research Funding, Speakers Bureau; Bristol Myers-Squibb: Consultancy; Pfizer: Consultancy. Harrison:Sierra Oncology: Honoraria; Gilead: Speakers Bureau; CTI: Speakers Bureau; Roche: Honoraria; Promedior: Honoraria; Janssen: Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Incyte: Speakers Bureau; Celgene: Honoraria, Speakers Bureau; AOP: Honoraria; Shire: Speakers Bureau. Mesa:Shire: Honoraria; Promedior: Research Funding; Genotech: Research Funding; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses; LaJolla: Consultancy; AbbVie: Research Funding; NS Pharma: Research Funding; CTI: Research Funding; Gilead Sciences: Research Funding; Samus: Research Funding; Baxalta: Consultancy; Galena Biopharma: Consultancy; Celgene Corporation: Research Funding; Sierra Oncology: Consultancy; PharmaEssentia: Research Funding; Genentech: Consultancy; Pfizer: Research Funding; AOP Orphan Pharmaceuticals: Honoraria, Other: travel, accommodations, expenses; Incyte: Other: travel, accommodations, expenses, Research Funding. Kiladjian:AOP Orphan: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene: Consultancy. Gale:Celgene Corporation: Employment. Laadem:Celgene Corporation: Employment, Equity Ownership. Pariseau:Celgene Corporation: Employment. Gerike:Celgene Corporation: Employment. Zhang:Celgene Corporation: Employment, Equity Ownership. Linde:Abbott Laboratories, Inc.: Equity Ownership; Acceleron Pharma: Employment, Equity Ownership; Fibrogen, Inc.: Equity Ownership. Reynolds:Acceleron Pharma: Employment, Equity Ownership. Verstovsek:Gilead: Research Funding; NS Pharma: Research Funding; Celgene: Consultancy, Research Funding; Promedior: Research Funding; CTI BioPharma Corp: Research Funding; Genetech: Research Funding; Blueprint Medicines Corp: Research Funding; Novartis: Consultancy, Research Funding; Sierra Oncology: Research Funding; Pharma Essentia: Research Funding; Astrazeneca: Research Funding; Ital Pharma: Research Funding; Protaganist Therapeutics: Research Funding; Constellation: Consultancy; Pragmatist: Consultancy; Roche: Research Funding; Incyte: Research Funding. OffLabel Disclosure: Luspatercept is an investigational therapy that is not approved for any use in any country. Luspatercept is currently being evaluated for potential use in patients with anemia due to myelodysplastic syndromes, beta-thalassemia, or myelofibrosis.

Background Although rituximab‐based high‐dose therapy is frequently used in diffuse large B cell lymphoma (DLBCL) patients undergoing autologous hematopoietic cell transplantation (auto‐HCT), data supporting the benefits are not available. Herein, we report the impact of rituximab‐based conditioning on auto‐HCT outcomes in patients who have DLBCL. Methods Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, 862 adult DLBCL patients undergoing auto‐HCT between 2003 and 2017 using BEAM (BCNU, etoposide, cytarabine, melphalan) conditioning regimen were included. All patients received frontline rituximab‐containing chemoimmunotherapy and had chemosensitive disease pre‐HCT. Early chemoimmunotherapy failure was defined as not achieving complete remission (CR) after frontline chemoimmunotherapy or relapse within 1 year of initial diagnosis. The primary outcome was overall survival (OS). Results The study cohort was divided into 2 groups: BEAM (n = 667) and R‐BEAM (n = 195). On multivariate analysis, no significant difference was seen in OS ( P = .83) or progression‐free survival (PFS) ( P = .61) across the 2 cohorts. No significant association between the use of rituximab and risk of relapse ( P = .15) or nonrelapse mortality ( P = .12) was observed. Variables independently associated with lower OS included older age at auto‐HCT ( P < .001), absence of CR at auto‐HCT ( P < .001) and early chemoimmunotherapy failure ( P < .001). Older age ( P < .0002) and non‐CR pre‐HCT ( P < .0001) were also associated with inferior PFS. There was no significant difference in early infectious complications between the 2 cohorts. Conclusion In this large registry analysis of DLBCL patients undergoing auto‐HCT, the addition of rituximab to the BEAM conditioning regimen had no impact on transplantation outcomes. Older age, absence of CR pre auto‐HCT, and early chemoimmunotherapy failure were associated with inferior survival.

Abstract Background: Thrombotic and hemorrhagic complications are commonly encountered in uncontrolled essential thrombocythemia (ET). Both anagrelide and hydroxyurea (HU) have proven efficacious in cytoreduction as well as reducing these events and remain first line therapy for most high-risk ET patients. Independent of their role in risk-reduction, little is known about how these therapies impact patient symptomatology or quality of life. In this study, we compared the clinical and symptomatic profiles of ET patients receiving HU or anagrelide against patients with no previous experience with these agents. Methods: Data was assessed from a prospectively collected international database of ET patients in which demographics, disease features, and ET symptoms utilizing the myeloproliferative neoplasm symptom assessment form (MPN-SAF; Scherber et al, 2011). The MPN-SAF includes the patient's perceptions of common MPN-related symptoms and overall quality of life (QOL) on a 0 (absent) to 10 (worst imaginable) scale. Total symptom score (TSS) was computed based on symptom items using the published scoring algorithm on a 0 (all reported symptoms absent) to 100 (all reported symptoms worst imaginable) scale. ET risk scores were calculated using the IPSET scoring algorithm (Passamonti 2012). Thrombocytopenia was defined as a platelet count <100 x 10(9)/L, anemia was defined as hemoglobin<10 g/dL and leukopenia was defined as a white blood cell count <4.0 x 10(9)/L. Associations between the MPN-SAF individual symptoms were investigated using chi-square test for categorical data and ANOVA F-test for continuous variables. Results Hydroxyurea vs. HU Naive A total of 402 ET patients with active HU use were compared to 392 ET patients with no history of HU use. Patients using HU were older (63.5 years vs. 52.3 years, p<0.001) and had a greater concentration of both high risk (24.9% vs. 11.4%, p=0.001) and intermediate risk (53.9% vs 38.4%, p<0.001) patients. They also had a higher rate of prior thrombosis (29.8% vs 11.3%, p<0.001) and leukopenia (10.1% vs. 3.0%, p<0.001). No differences were noted between gender, a history of prior hemorrhage, red blood cell transfusion requirements, or the presence of anemia/thrombocytopenia. In comparing symptom profiles, no significant differences were noted between TSS or individual symptoms with the exception of slightly more severe cough in HU patients (1.5 vs. 1.1, p=0.02, Figure 1). Anagrelide vs. Anagrelide Naive A total of 49 ET patients with active anagrelide use were compared to 794 ET patients with no history of anagrelide use. Patients using anagrelide had a longer mean disease duration (8.1 years vs. 5.8 years) and were more anemic (9.1% vs. 1.2%, p<0.001). No differences were noted between age, gender, risk scores, the presence of leukopenia/thrombocytopenia, a history of prior thrombosis or hemorrhage complications or red blood cell transfusion requirements. Additionally, there were no significant differences between TSS or individual symptom items (Figure 1). HU vs. Anagrelide A total of 402 patients currently using HU were compared to 39 patients currently using anagrelide. Overall, HU users were slightly older (63.5 years vs. 55.1 years, p<0.001) with a greater population of patients meeting high risk criteria (24.9% vs. 2.8%, p=0.002) and having a history of prior thrombosis (29.8% vs. 12.8%, p=0.02). Patients receiving anagrelide had a slightly longer disease duration (8.2 years vs. 6.0 years, p=0.0446). In comparing symptom profiles, no differences were noted in TSS or individual symptom items between cohorts. Discussion In this retrospective analysis, it does not appear cytoreduction with either HU and/or anagrelide has a significant impact on ET symptom burden despite reducing vascular events. Importantly, the higher risk scores in HU patients did not translate directly into greater patient symptomatology supporting previous studies demonstrating a poor association between these two items. Prospective trials measuring ET symptom change, in the setting of randomized trials will better quantify impact of cytoreduction on symptom burden as well as quantify impact of newer agents such as interferon or jak inhibition. Figure 1. Symptom Comparisons Between HU, Anagrelide and Other Therapy Figure 1. Symptom Comparisons Between HU, Anagrelide and Other Therapy Disclosures Kiladjian: Incyte Corporation: Consultancy; Novartis: Other: Travel grant; Research Funding paid to institution (Hôpital Saint-Louis et Université Paris Diderot); Novartis: Consultancy. Zweegman:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Harrison:Sanofi: Honoraria, Speakers Bureau; Shire: Speakers Bureau; Gilead: Honoraria; CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Cervantes:Sanofi-Aventis: Consultancy; Novartis: Consultancy, Speakers Bureau; CTI-Baxter: Consultancy, Speakers Bureau. Barbui:Novartis: Speakers Bureau. Etienne:ARIAD: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: Congress Travel/Accomodations, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau. Roy:Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding. te Boekhorst:Novartis: Consultancy; CTI Biopharma: Consultancy. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Speakers Bureau; Novartis: Other: Research Funding paid to institution (University of Florence), Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.

Abstract Background Myelofibrosis (MF) is a myeloproliferative neoplasm (MPN) characterised by the frequent presence of driver mutations in genes causing activation of JAK2 signalling pathways (JAK2, CALR and MPL). Additional mutations affecting epigenetic regulators and splicing machinery are common. Anaemia with RBC-transfusion-dependence is common in patients with advanced myelofibrosis and represents a major unmet need. The RESUME study assessed the rates of RBC-transfusion independence (TI) after therapy with Pomalidomide (POM) vs placebo in persons with MPN-associated myelofibrosis and RBC-transfusion dependence. 16% of patients in both the POM and placebo arms became TI. Aims The genetic landscape of strictly confirmed transfusion dependent MF is not fully characterised. Our aim was to analyse the genetics of transfusion-dependent myelofibrosis patients in the RESUME trial and correlate with clinical characteristics, outcome and therapy response. Methods DNA samples were available from 207 of 252 patients and analysed by targeted re-sequencing using a Fluidigm Access Array gene panel followed by next generation sequencing. The panel included JAK2, CALR, MPL, TET2, ASXL1, EZH2, DNMT3A, IDH1/2, CBL, IKZF1, U2AF1, CHEK2, TP53, SF3B1, SRSF2, SH2B3, BARD1, DAP3, HRAS, IRF4, KRAS, KIT, Mir662, NFE2, POLG, SCRIB, SETBP1, TCF12 and VPS45. Results 97% (95-99%) of subjects had a mutation in ≥1 targeted gene. 2 mutations were detected in 41% (34-48%) and ≥3 in 27% (21-33%). 7 had no detectable mutation. Mutations in JAK2V617F, CALR and MPL were identified in 66% (59-72%), 14% (8-19%) and 7% (4-11%) of subjects (Figure 1), with no driver mutation in 27 patients (13%; 9-18%) (triple-negative). 68% (61-74%) had additional non-driver mutations. 42% (35-48%) (N=86) had spliceosome mutations (U2AF1 [21%]; SF3B1 [11%]; SRSF2 [8%]; ZRSR2; [6%]). More spliceosome mutations were detected in men than women (47% [39-55%] vs 27% [15-40%]; p=0.009). Spliceosome mutations were mutually exclusive in 83 subjects and were less common in subjects with prior polycythaemia vera (17% [5-37%]) compared with prior essential thrombocythaemia (39% [22-58%]) and primary MF (46% [38-54%]; p=0.024). Mutations in epigenetic regulators (ASXL1, 28%; TET2, 8%; DNMT3A 5%; EZH2 4%) were detected at similar rates to those previously reported. High molecular risk (HMR) mutations (ASXL1, EZH2, IDH1/2, SRSF2) were detected in 36% [29-43%] of subjects. Only 10 of 105 subjects with an epigenetic regulator gene mutation had ≥1 related mutation. Subjects with JAK2V617F were significantly more likely than subjects with a CALR mutation to have: (1) ≥1 additional mutation (72% [64-79%] vs. 35% [18-54%], p=0.0001); (2) a spliceosome mutation (44% [36-53%] vs. 17% [6-36%], p=0.07), in particular a U2AF1 mutation (24% [17-32%] vs. 0%; p=0.004) and (3) a HMR mutation (38% [30-47%] vs. 21% [8-40%]; p=0.07). Survival at 1.5 years was 62% (55-67%) and was not significantly associated with the presence or number of mutations in this uniformly high-risk cohort. Survival in subjects without an SF3B1 mutation was better than those SF3B1-mutated (80% [56-91%]) vs. 59% [52-65%]; p=0.07). Driver mutation status did not influence the probability of achieving red blood cell (RBC) TI, regardless of therapy. Additional non-driver mutations were more often detected in those failing to achieve RBC-TI than those achieving RBC-TI (70% [63-77%] vs 56% [40-71%], p=0.07). Furthermore, those with additional non-driver mutations were less likely to achieve ≥50% reduction in RBC transfusions (24% [17-32%] vs. 39% [27-51%]; p=0.03). A significant correlation persisted in subjects receiving POM but not in those receiving placebo. There was also a significant correlation between U2AF1 mutations and RBC-TI in POM treated subjects compared with controls; U2AF1-mutated subjects were less likely to achieve RBC-TI (3% [1, 17%]) than U2AF1-unmutated subjects (25% [17, 34%], p=0.008). No other mutations were significantly correlated with response. Conclusion We found a high incidence of spliceosome mutations in persons with MPN-associated MF and RBC-transfusion-dependence. Mutation of U2AF1 correlated with response in subjects receiving POM but not in those receiving placebo. Incorporation of mutation profiling into clinical trial design may help to inform subgroups of patients that may benefit from the intervention. Disclosures Devos: Novartis: Consultancy; Celgene: Consultancy; Takeda: Consultancy. Gisslinger:Shire: Consultancy, Honoraria; Novartis: Honoraria, Research Funding; AOP Orphan Pharmaceuticals AG: Consultancy, Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria. Kiladjian:Celgene: Membership on an entity's Board of Directors or advisory committees; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Mesa:Celgene: Research Funding; UT Health San Antonio - Mays Cancer Center: Employment; Pfizer: Research Funding; Gilead: Research Funding; NS Pharma: Research Funding; CTI Biopharma: Research Funding; Incyte Corporation: Research Funding; Novartis: Consultancy; Promedior: Research Funding; Genentech: Research Funding. Ribrag:argenX: Research Funding; BMS: Consultancy, Honoraria, Other: travel; NanoString Technologies: Consultancy, Honoraria; pharmamar: Other: travel; Infinity: Consultancy, Honoraria; MSD: Honoraria; Amgen: Research Funding; Gilead: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Roche: Honoraria, Other: travel; epizyme: Consultancy, Honoraria; Incyte Corporation: Consultancy. Schiller:Celator/Jazz Pharmaceuticals: Research Funding; Pharmacyclics: Research Funding. Vannucchi:Celgene: Membership on an entity's Board of Directors or advisory committees; ITALFARMACO: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Reiser:Celgene: Employment. Zhong:Celgene: Employment. Mead:Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; ARIAD: Consultancy; Bristol-Myers Squibb: Consultancy; Cell Therapeutics: Consultancy; Celgene: Research Funding; Elstar: Research Funding; Evotek: Research Funding.

Abstract BACKGROUND: Both thalidomide (Br J Haematol2002;117:288) and lenalidomide (Blood2006;108:1158) are effective for alleviating anemia in approximately 20% of patients with myelofibrosis (MF). However, the value of these drugs is undermined by their respective potential for peripheral neuropathy and severe myelosuppression. In the current study, we evaluated the safety and efficacy of the new immunomodulatory drug, pomalidomide (POM) in MF. METHODS: This is a phase-2 randomized, multicenter, double-blind, active-control, parallel-group study to determine safety and select a “Best” dose of POM alone or combined with prednisone (PRED). Patients were equally randomized to 4 treatment groups: POM (2 mg/day) + placebo, PRED (30 mg/day) + placebo, POM (2 mg/day) + PRED (30 mg/day), and POM (0.5 mg/day) + PRED (30 mg/day). POM therapy was given for up to twelve 28-day treatment cycles. PRED therapy was given in a tapering dose schedule during the first three of these 12 treatment cycles. Protocol eligibility criteria included absolute neutrophil count of ≥ 1 × 109/L, platelet count of ≥ 50 × 109/L and hemoglobin level of < 10 g/dL including red blood cell (RBC) transfusion requirement. Patients with prior thalidomide or lenalidomide therapy and/or venous thrombosis were excluded from study participation. Response was assessed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) criteria (Blood.2006;108:1497) and by independent analysis of the component variables. RESULTS: A total of 104 patients with MF were assessed for eligibility; 85 were randomized and 84 received the assigned therapy. Blinded data for the first 82 patients are presented here; median age was 67 years and MF subtype was PMF in 70% of the patients and post-PV/ET MF in 30%. All patients belonged to either intermediate or high risk disease category (Blood1996;88:1013); 42 (51%) were RBC transfusion-dependent. Median duration of disease before randomization was 3 years (range 2–14). The number of patients assigned to each arm was relatively balanced: 21, 20, 19 and 22, respectively. After a median treatment duration of 3 months, 42 (51%) patients have discontinued protocol therapy because of lack of therapeutic effect (n=19), withdrawal of consent (n=11), adverse event (n=11) or death (n=2). Grade 3/4 adverse events (regardless of attribution) included anemia (10%), thrombocytopenia (9%), leukopenia (9%), fatigue (7%), dyspnea (5%), thrombosis (4%), diarrhea (4%) and hyperglycemia (4%). Combined response rate using IWG-MRT criteria was 25% (95% CI, 16–34%) and ranged between 11% and 42% among the four treatment arms. CONCLUSION: Pomalidomide, with or without concomitant prednisone therapy, is well tolerated in patients with MF, especially from the standpoint of myelosuppression. Response rates are high. Additional, unblinded, information regarding response details, remission duration and laboratory correlative studies will be presented at the meeting.

Abstract Abstract 897 Recent changes in allogeneic hematopoietic cell transplantation (HCT) including increased use of reduced-intensity conditioning, peripheral blood cells as the graft source (PB) and unrelated donors (URD) warrant re-evaluation of risk factors for acute graft-versus-host disease (aGVHD) and its impact on overall survival (OS). Risk factors for these outcomes were analyzed using more recent data from CIBMTR observational database. Methods: The cohort included adult patients ≥ 20 y transplanted from an HLA-identical sibling (SD) (n=3191) or URD (N=2370) for acute myelogenous leukemia (AML), acute lymphoid leukemia (ALL), chronic myeloid leukemia (CML), or myelodsyplastic syndrome (MDS) using a T-cell replete graft from 1999–2005. Six groups were created to evaluate the impact of conditioning [(myeloablative (MA) and reduced-intensity or non-myeloablative (RIC)], total-body irradiation (TBI) and graft source [(bone marrow (BM) or PB] as follows: MA+TBI+PB (group 1), MA+TBI+BM (group 2) MA+ no TBI+PB (group 3), MA+ no-TBI+BM (group 4), RIC+PB (group 5) and RIC+BM (group 6). Separate analyses were performed for SD and URD. IBMTR grade was used to classify aGVHD. A p-value of ≤ 0.01 was considered significant. Results: Among the SD cohort, the probability of aGVHD grade B-D and grade C-D at 100 days was 39% (95% CI, 37–41%) and 16% (95% CI, 14–17%). In multivariate analyses, non-TBI based MA regimens with a BM graft (group 4), RIC conditioning with PB (group 5) and tacrolimus plus methotrexate aGVHD prophylaxis were associated with lower odds ratio of grade B-D aGVHD (Table 1). The probability of OS was 51% (95% CI: 49–53%) at 3 y and 46% (95% CI: 44–49%) at 5 y. In multivariate analyses, grade B-D aGVHD was associated with a higher risk of death. Other independent risk factors for OS are shown in Table 2. Among the URD cohort, the probability of aGVHD grade B-D and C-D at 100 days was 59% (95%, CI 57–61%) and 32% (30-34%). In multivariate analysis, BM with MA (TBI and no TBI) or RIC conditioning (groups 2, 4 and 6) were significantly associated with lower odds ratio of grade B-D aGVHD (Table 1). Other independent risk factors included a diagnosis of CML. HCT from a 7/8 HLA-mismatched URD showed a trend for higher incidence of aGVHD (p=0.02). The probability of OS was 38% (95% CI: 35–40%) at 3 y and 33% (95% CI: 31–35%) at 5 y. In multivariate analysis, grade B-D aGVHD was associated with a higher mortality. Table 2 shows other independent risk factors for OS. Conclusion: Intensity of the conditioning regimen, TBI and the graft source has a combined effect on the risk of aGVHD. In both SD and URD cohorts, BM with MA, non-TBI regimens were associated with lower risk of aGVHD. In URD cohort, BM after a RIC also was associated with a reduced risk of aGVHD. Modulation of these risk factors is needed to reduce acute GVHD incidence and death after allogeneic transplantation. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Myelofibrosis (MF) is a clonal myeloproliferative neoplasm (MPN) associated with a high degree of symptomatology, progressive cytopenias and potential to transform into acute myelogenous leukemia (AML). Thrombocytopenia amongst MF patients is a proven negative prognostic indicator and predictor of transformation to AML. Ruxolitinib is an effective JAK inhibitor for MF symptoms and splenomegaly, but is not indicated in patients with severe thrombocytopenia. Phase III trials of pacritinib have shown alleviation of the MF symptom burden amongst patients with thrombocytopenia (ASCO 2015 Mesa et. al.). In this study, we assessed the symptom burden of MF patients with significant thrombocytopenia who were naïve to pacritinib. Methods Data was assessed from a prospectively collected international database of MF patients in which demographics, disease features, and MF symptoms utilizing the myeloproliferative neoplasm symptom assessment form (MPN-SAF; Scherber et al, 2011). The MPN-SAF includes the patient's perceptions of common MPN-related symptoms and overall quality of life (QOL) on a 0 (absent) to 10 (worst imaginable) scale. Total symptom score (TSS) was computed based on symptom items using the published scoring algorithm on a 0 (all reported symptoms absent) to 100 (all reported symptoms worst imaginable) scale. MF risk scores were calculated using the DIPSS criteria (Gangat, 2011). Thrombocytopenia was defined as a platelet count <100 x 10(9)/L, anemia was defined as hemoglobin<10 g/dL and leukopenia was defined as a white blood cell count <4.0 x 10(9)/L. Associations between the MPN-SAF individual symptoms were investigated using Pearson correlations. Results Demographic and Disease Features: A total of 418 patients with (n=89) and without (n=329) thrombocytopenia completed the MPN-SAF. Patients with thrombocytopenia were slightly younger (57.4 vs. 61.0, p=0.01) with longer disease durations (11.9 years vs. 8.8 years, p=0.0489) and had a higher prevalence of primary myelofibrosis (PMF; 82% vs. 66%, p=0.01). The presence of thrombocytopenia was associated with other laboratory abnormalities including anemia (60.7% vs. 25.3%, p<0.001) and leukopenia (34.8% vs. 52.3%, p<0.001), along with the need for red blood cell transfusions (34.8% vs. 14.6%, p<0.001). Patient cohorts did not differ by gender, DIPSS risk score, history of prior thrombosis or hemorrhage. In comparing patients with severe thrombocytopenia (<50 x 10(9)/L, n=43) to those with moderate thrombocytopenia (51-100 x 10(9)/L, n=46), severe thrombocytopenia patients were more likely to have anemia (74.4% vs. 47.8%, p=0.01) and require red blood cell transfusions (51.2% vs. 19.6%, p=0.002). Symptoms Scores for individual MPN-SAF items were assessed for each subgroup. Patients with thrombocytopenia had markedly higher total symptom scores than patients without thrombocytopenia (32.8 vs. 24.1, p<0.001). Individual scores were also higher for most items (fatigue, early satiety, inactivity, dizziness, sad mood, sexuality, cough, night sweats, itching, fever, weight loss, overall QOL)[Figure 1]. No significant differences in MPN SAF TSS or individual symptom scores were observed in comparing severe vs. moderate thrombocytopenia patients. Discussion MF patients with thrombocytopenia have distinctive clinical characteristics and face a significantly more severe symptom burden. Importantly, despite thrombocytopenia being a recognized risk factor for disease advancement, no correlations are noted between patient symptomatology and risk category. In addition, patients with severe thrombocytopenia do not differ symptomatically from patients with moderate thrombocytopenia despite having more severe anemia, leukopenia and transfusion requirements. This implies that the degree of symptomatology expressed by thrombocytopenic MF patients occurs independent from the exact platelet value. Conclusion The results of this study suggest that patients with thrombocytopenia will benefit from aggressive symptomatic control, potentially from targeted agents. Figure 1. MF Symptoms in Patients With and Without Thrombocytopenia Figure 1. MF Symptoms in Patients With and Without Thrombocytopenia Disclosures Kiladjian: Novartis: Consultancy; Novartis: Other: Travel grant; Research Funding paid to institution (Hôpital Saint-Louis et Université Paris Diderot); Incyte Corporation: Consultancy. Zweegman:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Harrison:Shire: Speakers Bureau; CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau; Gilead: Honoraria; Novartis: Honoraria, Research Funding, Speakers Bureau. Cervantes:Novartis: Consultancy, Speakers Bureau; Sanofi-Aventis: Consultancy; CTI-Baxter: Consultancy, Speakers Bureau. Barbui:Novartis: Speakers Bureau. Etienne:ARIAD: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: Congress Travel/Accomodations, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau. Roy:BMS: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Vannucchi:Shire: Speakers Bureau; Novartis Pharmaceuticals Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.