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Abstract Background Despite over a decade of evidence, uptake of GLS into guidelines and practice has been slow. Age, BP, and software have been reported to influence GLS, and have led to uncertainty about defining the normal range (NR). As there have been software changes since the last meta-analysis, we sought to define NR in the current era. Methods Pubmed, Cochrane, and EMBASE were searched using the keywords “Left Ventricle”, “Normal global longitudinal strain”, and “Speckle tracking Echocardiography” and relevant synonyms from 2011. Studies were included if they reported GLS based on speckle tracking techniques, included at least 20 healthy individuals, and had up to date contact details available. Healthy was defined as lack of known disease. Platforms used included General Electric, Philips, Canon and Tomtec. The authors of 8 of the 12 studies (67% response) provided individual patient data. Linear regression was used to determine predictors of GLS. Results There were 2396 pts, mean age 42 years (range 18–92), weight 66±12kg, height 169±9cm, BSA 1.7±0.2m2, and SBP 120±13 mmHg. Normal range for GLS was 21.0±2.6%. In multivariable analysis age (β=-0.02, p<0.01), weight (β=-0.03, p<0.01), SBP (β=-0.01, p<0.01) and platform were associated with GLS. GLS tends to vary with extremes of age and BP (see Figure 1 and Figure 2). GLS vs Age group Conclusion Extremes of age and BP may lead to low GLS, but generally, GLS is <16% is abnormal. Acknowledgement/Funding None

Abstract Abstract 288 BACKGROUND. Chronic lymphocytic leukemia (CLL) patients with mutated IGHV genes (M-CLL) have better outcomes than patients with unmutated IGHV genes (U-CLL). It has been proposed that this difference reflects the fact that IGHV mutations alter the structure of the B-cell antigen receptor (BCR) such that it no longer binds stimulatory (auto) antigens and therefore cannot deliver trophic signals to the leukemic cells. For this theory to be correct, only replacement (R) mutations and in particular non-conservative R mutations that would more likely alter amino structure of the IGHV/D/J rearrangements would have relevance. Silent (S) mutations by definition do not change amino acid structure and could not alter antigen binding. We sought to investigate this hypothesis by analyzing the types (S, conservative R, non-conservative R) and distribution of mutations that occur in IGHVs of M-CLL clones and then comparing the time to first therapy (TTFT) in patients with different IGHV features. This analysis expanded an initial study of 1569 CLL cases in the US to include 1858 patients from Europe for a total of 3427 cases. METHODS. Using IGMT software and tools, we analyzed the rearranged IGHV sequences of 3427 cases and characterized their mutations in several respects: first, if IGHV mutations altered amino acid structure (S vs. R); second, if mutations occurred in CDRs (antigen binding domains) or FRs (scaffolds of the BCR); third, if R mutations were conservative or non-conservative as determined by charge, hydropathy, and size. TTFT for patients was examined with various combinations of the above parameters. Differences in TTFT were estimated by the method of Kaplan and Meier and assessed using the log rank test. RESULTS. First, TTFT was compared for 4 groups of patients with the following mutation profiles: no mutations; only S mutations (median 1 per sample); only R mutations (median 1 per sample); and mixed S and R mutations (median 16 per sample). These 4 categories were significantly different (P<0.0001), with the median TTFT being 2.0 yrs for no mutations; 2.6 yrs for R only; 2.8 yrs for S only; and 7.3 yrs for mixed. All comparisons used patients with no mutations (n=1234) as the reference group. We identified statistically longer TTFT (2.8 vs 2.0 yrs; P=0.04) in patients with only S mutations (n=62). Patients with only R mutations (n=218) also had superior outcomes (2.6 yrs vs. 2.0 yrs; P=0.008). There was no statistical significance in TTFT between patients with all S vs. all R mutations (2.8 yrs vs. 2.6 yrs; P=0.71). Because exploring the relevance of BCR structural change on TTFT required us to focus on a small subset of patients with only silent IGHV mutations, our sample size was small. Therefore, we expanded the group to include IGHVs with R mutations limited to the FR region (S + R in FR only; n=241) since these mutations would be unlikely to have a major impact on BCR structure, particularly sparing the binding site. When compared to patients with no mutations, this group demonstrated a significantly longer TTFT (2.8 yrs vs. 2.0 yrs, P=0.0002). This finding was upheld when not permitting any non-conservative R mutations in this group, leaving only patients with S plus conservative R mutations in FRs only (n=124); TTFT in this case was 2.8 yrs vs. 2.0 yrs, respectively (P=0.0006). CONCLUSIONS. Our findings show that patients with only S mutations have better outcomes than patients with no mutations, suggesting that a change in BCR structure that could lead to a loss of antigen binding is an unlikely reason for improved clinical course. This is further supported by the finding that the combination of only S plus conservative R mutations located solely in FRs, which probably would not result in major BCR structural changes and therefore antigen binding, is associated with a lengthened TTFT. Therefore, we suggest that the currently accepted paradigm to explain the enhanced survival of M-CLL patients needs to be re-evaluated. Disclosures: Brown: Calistoga: Consultancy, Research Funding; Celgene: Honoraria, Research Funding; Genzyme: Research Funding; GSK: Research Funding. Kipps:Igenica: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding; Abbott Industries: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; GSK: Research Funding; Gilead Sciences: Consultancy, Research Funding; Amgen: Research Funding.

Abstract Background: Patients (Pts) with multiple myeloma (MM) who relapse within 12 months of autologous stem cell transplantation (SCT) have a poor prognosis. As reported by Mahmood et al. (ASCO 2007), of 432 pts who received SCT at the Mayo Clinic between 1994–2005, those with early relapse within 12 months (94/432– 22%) showed poorer median overall survival. Kaplan-Meier estimates of 12-month survival from the date of first relapse were 37% for pts relapsing within 12 months after SCT as compared to 85% for those relapsing after 12 months. In that study, pts had received regimens other than B. In a recent report of a large, phase III study (DOXIL-MMY3001), the combination of PLD+B improved time to progression (TTP) as compared to B alone (Orlowski et al. JCO 2007). The present analysis examined the 12-month post-randomization survival of patients who had early (<12 months) vs. late (≥12 months) relapse following SCT, as well as the effect of PLD+B vs. B alone in pts who had relapsed early. Methods: This was a retrospective analysis of 646 pts who received intravenous B, 1.3 mg/m2 on days 1,4,8 and 11 of every 21-day cycle ± PLD, 30 mg/m2 on day 4. Results: 359 pts had previously received transplant, 114 (32%) of whom relapsed within 12 months from SCT. The median age, gender distribution, time from diagnosis trial enrollment, measures of disease burden (M-Protein levels and B2M) and renal function were comparable between the early and late relapse groups. There was no difference in overall response rates [complete + partial response (CR+PR)] or very good PR (VGPR) rates between the two groups, or between treatment arms within each group. There was no significant difference in TTP between early vs. late relapse groups (HR=0.94). 12-month survival from randomization was significantly lower in the early relapse group as compared to late relapse (83% vs. 92% respectively, p=0.009). However, within the early relapse group 12-months post-randomization survival rate was significantly superior following treatment with PLD+B as compared to B alone [52/56 patients (93%) vs. 43/58 patients (74%) respectively, p=0.01]. Correspondingly, TTP was better in this group with PLD+B vs. B alone (276 days vs. 205 days respectively, p=0.13). Overall, the toxicity profiles of the combination and B alone were comparable regardless of early or late relapse following SCT. Conclusions: The present analysis of the MMY3001 study corroborates the prior Mayo observation of lower survival in MM pts relapsing within 12 months of SCT. Importantly, it demonstrates that PLD+B may provide a therapeutic advantage for high-risk MM pts with early relapse following SCT.

Abstract Introduction: Rearrangements of the MLL (mixed lineage leukemia) gene on chromosome 11q23 are present in 5-10% of either acute myeloid (AML) or acute lymphoblastic leukemia (ALL), and are associated with a poor prognosis. Fusion proteins involving the MLL histone methyltransferase (HMT) result in recruitment of another HMT, DOT1L, to a multi-protein complex leading to aberrant methylation of Histone H3 lysine 79 (H3K79) at MLL target genes and enhanced expression of leukemogenic genes such as HOXA9 and MEIS1. EPZ-5676 is a small molecule inhibitor of DOT1L with sub-nanomolar affinity and >37,000 fold selectivity against additional HMTs. EPZ-5676 treatment of cultured cells reduced histone H3K79 methylation, decreased MLL target gene expression and resulted in selective killing of MLL-rearranged (MLL-r) leukemia cells by inducing apoptosis and differentiation. EPZ-5676 administration led to tumor regression in an MLL-r leukemia xenograft model. We report preliminary results of an ongoing Phase 1 trial of EPZ-5676 in patients with advanced hematologic malignancies, including acute leukemia with MLL-r. Methods: This is a 2-part phase 1 open label dose escalation study investigating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and anti-leukemic activity of EPZ-5676 in adult patients (pts) with relapsed/refractory leukemia (CT.gov: NCT01684150). In the dose-escalation phase, patients with AML, ALL, acute mixed lineage leukemia, myelodysplastic syndrome, myeloproliferative neoplasia (MPN) or chronic myeloid leukemia were eligible. Eligibility in the expansion phase of the study was restricted to pts with MLL-r or partial tandem duplication of MLL (MLL-PTD). EPZ-5676 was administered via continuous intravenous infusion (CIV) for 21 days of a 28 day cycle in the dose escalation phase and CIV for all 28 days of a 28 day cycle in the expansion phase, until disease progression or unacceptable toxicity. Results: Between October 2012 and July 2014, 37 pts have enrolled; 36 are evaluable for safety (received at least 1 dose of EPZ-5676) and 28 pts (19 MLL-r, 4 MLL-PTD) are evaluable for anti-leukemia activity (completed at least one post baseline marrow evaluation). The median age at time of enrollment was 53 years (range: 20 to 81 years); the median number of prior systemic therapies was 2 (range: 1 to 6) and 14 pts had a prior allogeneic stem cell transplant. Of the treated pts, disease characteristics were: 31 pts with AML (21 MLL-r, 5 MLL-PTD), 4 pts with ALL (3 MLL-r) and 1 pt with MPN (MLL-r). Table 1: Number of evaluable pts per cohort Dose (mg/m2/day) 12 24 36 54 80 90 21 day CIV 1 5 4 6 3 - 28 day CIV - - - - - 17 The median time on study was 29 days (range: 5-196 days). Adverse events (AEs) reported in >15% of pts were: anemia, fever/neutropenia, thrombocytopenia, constipation, diarrhea, nausea, chills, fatigue, mucosal inflammation, peripheral edema, hypomagnesemia, dyspnea and sepsis; of which leukocytosis, nausea and hypomagnesemia were assessed by the investigator as drug related. Grade I PR interval prolongation, without associated QTc changes, was observed in 2 pts. There were no deaths attributed to study drug treatment, and there were 2 pts with treatment discontinuation for potentially drug-related AEs. Dose proportional PK was observed with rapid attainment of steady-state plasma concentrations on Day 1 of treatment. Preliminary PD data demonstrated inhibition of H3K79 methylation from baseline in marrow (median: 52%, range 0-81%) and peripheral blood mononuclear cells (median: 43%, range 25-67%) at doses above 36 mg/m2/day. PD effects were observed by day 8. The 21 day CIV pts recovered H3K79 methylation towards baseline by day 28, and the 28 day CIV pts maintained methyl-mark inhibition throughout cycle 1. To date, best responses for pts with MLL-r are morphologic CR (1 pt.), cytogenetic CR (1 pt), and resolution of leukemia cutis (2 pts). In addition, a treatment-related increase in neutrophils (PMN) and/or monocytes was observed in 6 pts with a median day of onset of 15 days (range 8-28 days). The identification of the MLL-r by split signal FISH in mature PMN suggests a differentiation effect on the leukemic clone. Conclusions: EPZ-5676 is well tolerated and exhibits anti-leukemic activity in MLL-rearranged acute leukemia. These data provide rationale for continued clinical investigation of potential utility of EPZ-5676 in patients with rearrangements of the MLL gene. Disclosures Stein: Janssen Pharmaceuticals: Consultancy. Garcia-Manero:Epizyme, Inc: Research Funding. Rizzieri:Novartis, Inc: Consultancy, Speakers Bureau; Ariad, Inc: Speakers Bureau. Savona:Karyopharm: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Altman:Astellas: Membership on an entity's Board of Directors or advisory committees; Ariad: Membership on an entity's Board of Directors or advisory committees; Spectrum: Membership on an entity's Board of Directors or advisory committees; Foundation Medicine: Membership on an entity's Board of Directors or advisory committees. Armstrong:Epizyme, Inc: Consultancy. Pollock:Epizyme: Employment, Equity Ownership. Waters:Epizyme, Inc: Employment, Equity Ownership. Legler:Epizyme, Inc: Employment. Thomson:Epizyme, Inc: Employment. Daigle:Epizyme, Inc: Employment, Equity Ownership. McDonald:Epizyme, Inc: Employment. Campbell:Epizyme, Inc: Employment, Equity Ownership. Olhava:Epizyme, Inc: Employment. Hedrick:Epizyme, Inc: Employment; Pharmacyclics, Inc: Equity Ownership. Copeland:New Enterprise Associates: Ad hoc consultant, Ad hoc consultant Other; Mersana: Membership on an entity's Board of Directors or advisory committees; Epizyme, Inc: Employment, Equity Ownership.

Abstract Abstract 3839 BACKGROUND: We have previously reported on the validation of the 18 item Myeloproliferative Neoplasm Assessment Form (MPN-SAF) (Blood 2011;118:401–408) given in conjunction with the 9 item Brief Fatigue Inventory (BFI) (Cancer 1999;85:1186–1196) to assess symptomatic burden in an international sample of MPN patients (pts), including validation in English, Italian, Swedish, German, French, Spanish, and Dutch. We desired to assess the utility of an average total symptom score (TSS) from the most pertinent and representative MPN symptoms for purposes of assessing the burden of symptoms in MPN pts, and subsequent tracking in response to therapy. METHODS: Data was collected among an international cohort of MPN pts and their physicians, including patient demographics and disease features and completion the BFI, MPN-SAF and the EORTC-QLQ-C30. Among pts who completed at least 5 of 10 specific items on the BFI and MPN-SAF, an average score was calculated as the TSS. TSS items included “worst” fatigue from the BFI and 9 items from the MPN-SAF including concentration, early satiety, inactivity, night sweats, itching, bone pain, abdominal discomfort, weight loss and fever. The TSS thus had a possible range of 0–10 with 10 representing the highest level of symptom severity. Data was then analyzed for internal consistency, and divergent, convergent validity, and construct validity. RESULTS: Patient Demographic and Disease Characteristics:1433 MPN pts were prospectively enrolled (Argentina 22, France 482, Germany 59, Italy 186, Netherlands 236, Puerto Rico 10, United Kingdom 57, United States 102, Spain 157, Sweden 114, Uruguay 8) including 594 ET, 538 PV and 293 MF pts (8 missing; MF: 61% Primary MF, 23% post-ET MF, 15% post-PV MF). 1408 pts completed at least 5 of the 10 items necessary to calculate a TSS. Pts were of characteristic age (mean 62, range 20–94) and gender (54% female) common to disease. TSS Burden of MPN Symptoms: Consistent with prior studies, the majority of pts (>50%) were symptomatic in each TSS item except for items associated with high disease severity, namely bone pain (48.6%), weight loss (30.6%) and fever (18.4%). Fatigue carried the highest symptom intensity (4.4, SD=2.8), followed by problems with concentration (2.5, SD=2.8) and early satiety (2.5, SD=2.7). Overall mean TSS was 2.1 (SD=1.6). Divergent Validity: TSS significantly differed among MPN disease subtypes (p<0.001) with means of 1.9 (SD=1.5), 2.2 (SD=1.6), and 2.5 (SD=1.7) for ET, PV, and MF pts, respectively. Statistically significant differences in TSS were also observed between pts with clinically deficient (>4, n=480) versus non-clinically deficient QOL (<4, n=894; mean 3.3 versus 1.5; p<0.001). When comparing to MD perceptions, TSS was significantly higher when MDs rated >2 of 6 common MPN-related symptoms as clinically significant (2.8, n=400) versus <2 symptoms (1.6, n=726; p<0.001). No significant trends were observed when comparing disease type by the presence of a current medical therapy. Convergent Validity: The TSS was strongly correlated with patient-reported QOL (r=0.59, p<0.001). Overall excellent correlations existed between the TSS and EORTC-QLQ-C30 functional subscales (all p<0.001 and r>0.50 except social functioning [r=0.48]). Additionally, excellent correlations were observed between the TSS and EORTC-QLQ-C30 fatigue and pain symptom scales (r>0.5, p<0.001). Internal Consistency and Construct Validity: The TSS had excellent internal consistency (Cronbach's alpha=0.83). Factor analysis identified a single underlying construct among the 10 TSS items (significant eigenvalues being >1). Factor loadings ranged from 0.43 for fever and weight loss to 0.71 for inactivity. The single factor suggests that the arithmetic mean of the 10 items is an appropriate global TSS score. CONCLUSION: The TSS demonstrated excellent psychometric properties. Overall, results of validity and internal consistency indicate that the TSS is a concise, valid, and accurate assessment of symptom burden among MPN pts. This new scoring will facilitate ease of implementation of the MPN-SAF into larger clinical trials and reduce ambiguity associated with interpreting response outcomes. Future analyses to investigate the impact of therapies on TSS are ongoing. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3989 Background: Treatment patterns of multiple myeloma (MM) vary across the globe, mostly dictated by the availability and patient access to different drug therapies. The outcomes of patients with MM, especially relapsed myeloma can be significantly affected by the availability of newer treatments, as well as potential biological differences related to ethnicity. We have previously shown that the outcome of patients relapsing after therapy with bortezomib (Bz) and one or more of the IMiDs remain poor with the currently available treatments and represent a difficult group of patients to treat. We undertook the current analysis on a set of patients from United States, several European countries and South Korea. Methods: We designed a multicenter, retrospective study that enrolled 294 patients with relapsed MM, from 14 sites (122 from Europe, 107 from US, and 65 from Korea). Patients were refractory to Bz, defined as no response to prior Bz-containing regimen or disease progression within 60 days of a Bz-containing regimen. Patients were also relapsed, refractory, intolerant, and/or ineligible, to treatment with an IMiD (thalidomide or lenalidomide). The date patients satisfied the above entry criteria was defined as time zero (T0). Clinical and laboratory data from diagnosis and individual relapses were collected along with details of all MM drug therapies before and after T0. Responses were assessed by IMWG or EBMT criteria. The goal of the study was to compare the characteristics of patients who satisfy the above inclusion criteria, the therapies employed prior to and after T0 and clinical outcome among these patients from different parts of the world. Results: The mean (median, range) time to reaching T0 from diagnosis was 4.5 (4.0, 12.8), 4.2 (3.2, 18.6), and 3.2 (2.8, 9.6) years from diagnosis for patients from US, Europe and Korea, respectively, P=0.021. The mean (median, range) number of therapies for the three groups were 8 (8, 13), 4 (4, 10), 5 (4, 7), respectively; P<0.001. The response rates (>=PR) to the initial therapy at diagnosis were 56%, 77% and 49% respectively for the US, European and Korean cohorts. Overall 220 patients had at least one therapy after T0, and 114 (52%) had a novel agent (Bz, len or thal) containing regimen as their first treatment after T0. Patients in US were more likely to receive additional therapies after the first post-T0 therapy; 62%, 32%, and 12% of patients from US, Europe and Korea, respectively, began a second post-T0 regimen within 2 years following time zero. The median number of therapies post T0 was 2, 1, and 1 for patients in US, Europe and Korea respectively. The response rates to the first regimen after T0 were 15%, 33% and 19% for the US, European and Korean cohorts, and were similar between those receiving a regimen with one of the novel drugs compared to rest. Patients younger than 60 years and those with prior transplants were more likely to respond to post T0 regimens. The median time to progression or death from T0was similar for the three patient cohorts, 5 months (Figure 1A). The median overall survival (95% CI) from T0 was 13 months (10, 16), 7 (5,9) and 8 (4,9) respectively for the US, European and Korean cohorts (Figure 1B). Conventional prognostic factors, especially the ISS stage was predictive of OS post T0. Additionally, presence of extramedullary disease was associated with a shorter overall survival. Conclusion: The results of the current study demonstrate significant differences between different parts of the world in terms of the treatment patterns both in the setting of initial therapy as well as treatment of relapsed disease. Patients in the US were more likely to receive multiple regimens both before and after T0. This is likely a reflection of increasing numbers of new drugs that have gone into clinical trials and thus enhancing options. The study further highlights the poor outcome of patients who have relapsed after the new drugs, irrespective of the geographical location. Disclosures: Kumar: Merck: Consultancy, Honoraria; Genzyme: Consultancy; Celgene: Consultancy. Richardson:Millennium: ; Celgene: ; Johnson & Johnson: ; Novartis: ; Bristol Myers Squibb:. Moreau:Millennium Pharmaceuticals, Inc.: Advisory board, Honoraria; Janssen: Advisory board, Honoraria. Sonneveld:Millennium Pharmaceuticals, Inc.: 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; Onyx: Membership on an entity's Board of Directors or advisory committees, Research Funding. Siegel:Merck: Honoraria; Millenium: Honoraria, Research Funding, Speakers Bureau. San Miguel:Janssen-Cilag: Honoraria; Celgene: Honoraria. Palumbo:celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Durie:Celgene: Membership on an entity's Board of Directors or advisory committees.

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.

Abstract Background: The Philadelphia chromosome negative myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF) all have a time dependent risk of progression to either an advanced myelofibrotic state (post ET/PV MF) and/or to acute myeloid leukemia. The impact of disease duration upon the MPN symptom burden is not well understood, nor are the precise mechanisms of disease progression. We sought to better understand the impact of disease duration on MPN symptom burden. Methods: Symptom burden data was collected utilizing the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) amongst MPN patients, collected at the time of an office visit in an international cohort of MPN patients as previously described (Scherber et. al.). Symptom burden assessment was a previously validated 27-item symptom burden questionnaire scored on a 0-10 scale (0= as good as it can be, 10 = as bad as it could be). The patient or provider was asked to report the time since MPN diagnosis. MPN duration was determined to be early if the diagnosis was established between 0 to 5 years ago, intermediate if the diagnosis was established between 6 to 10 years ago, and late if the diagnosis was established 11 years ago or more. Anemia was defined as a red blood cell count less than 10 g/dL, leukopenia was defined as a white blood cell count was below 4 x 109, and thrombocytopenia if the platelet count was below 150 x109. Statistical significance was calculated using ANOVA f-test and chi squared. Results: Patient demographics and disease burden: A total of 1443 patients responded to the survey, including 592 (41%) ET, 549 (38%) PV, and 302 (21%) MF patients, including 181 (60%) primary MF, 67 (22%) post-ET MF, and 54 (18%) post-PV MF. Among MF patients, mean duration of MPN diagnosis was 9 years, and mean duration MF diagnosis was 4.7 years. Among respondents, 757 fit criteria for early disease duration, 353 fit criteria for intermediate disease duration, and 333 fit criteria for late disease duration. Respondent mean age was 62 years and approximately half of respondents were female (55%). Patients with longer diagnosis duration tended to be older (p=0.009) and were most likely to have anemia (0.02), leukopenia (p=0.01), or thrombocytopenia (p=0.03). These individuals were also most likely to have a history of hemorrhage (p=0.007) or require red blood cell transfusions (p<0.001). Combined cohort symptom burden: On average among the combined cohort of ET, PV and MF patients, symptoms tended to worsen with time with this effect being significant for symptom items of fatigue (BFI, p<0.04), concentration (p=0.007), insomnia (p=0.02), sexual difficulties (p=0.002), cough (p=0.03), night sweats (p=0.002), and pruritus (p=0.02). Symptoms of early satiety (p=0.004), concentration difficulties (p=0.01), insomnia (p=0.03), sexual difficulties (p=0.02), cough (p=0.01), and night sweats (p=<0.001) had significantly higher prevalence in those with longer disease duration. Similarly, the total calculated MPN-10 score (p=0.008) and quality of life assessment (0.03) demonstrated worsened outcomes with time (Table 1). No significant differences in symptoms for the combined cohort were observed among individuals diagnosed 0 to 1 years ago compared to those with a diagnosis established between 2 and 5 years ago. Symptom burden in MPN subtypes. When evaluating specific MPN types, patients with essential thrombocythemia experienced significantly greater sexual difficulties over time (p=0.03). The severity (p=0.01) and incidence (p=0.03) of pruritus and incidence of night sweats (p<0.001) were significantly increased over time for individuals with PV. For those with MF, the severity (p= 0.01) and incidence (p=0.009) of cough also significantly increased with longer diagnosis duration. Discussion Overall, significant worsening in symptom burden can be recognized over time for individuals diagnosed with MPNs. Diagnosis may not necessarily correlate with disease duration as the timing of diagnosis may be delayed from onset of disease. Given the intent of this abstract to evaluate changes with disease duration, we did not investigate correlations between symptom burden and cytopenias. We do know that risk factors for survival in the MPNs include older age and thrombosis, however, disease duration should be investigated as an alternative marker of burden in future survival studies. Disclosures Harrison: CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Shire: Speakers Bureau; Gilead: Honoraria; Novartis: Honoraria, Research Funding, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau. Kiladjian:Incyte Corporation: Consultancy; Novartis: Other: Travel grant; Research Funding paid to institution (Hôpital Saint-Louis et Université Paris Diderot); Novartis: Consultancy. Zweegman:Celgene: Research Funding; Janssen: Research Funding; Takeda: Research Funding. Barbui:Novartis: Speakers Bureau. Etienne:Novartis: Consultancy, Honoraria, Other: Congress Travel/Accomodations, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; ARIAD: Consultancy, Honoraria, Speakers Bureau. te Boekhorst:CTI Biopharma: Consultancy; Novartis: Consultancy. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Other: Research Funding paid to institution (University of Florence), Research Funding; Shire: 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.

Abstract Introduction: Aberrant fusion proteins involving the MLL histone methyltransferase (HMT) result in recruitment of another HMT, DOT1L, to a multi-protein complex. This leads to abnormal methylation of Histone H3 lysine 79 (H3K79) at MLL target genes and enhanced expression of leukemogenic genes such as HOXA9 and MEIS1 ( Krivstov, 2007). Pinometostat is a small molecule inhibitor of DOT1L with sub-nanomolar affinity and >37,000 fold selectivity against non-MLL HMTs. Pinometostat treatment of MLL-rearranged cells and xenografts reduced histone H3K79 methylation, decreased MLL target gene expression, and induced selective leukemia cell kill (Daigle, 2013). We report the safety, activity, pharmacokinetics (PK) and pharmacodynamics (PD) in the phase 1 trial of pinometostat in adult patients (pts) with relapsed/refractory (R/R) leukemia. Methods: This open label dose escalation/expansion study of pinometostat enrolled pts >18 years (yrs) with R/R leukemia (NCT01684150). In the dose-escalation phase, pts with AML, ALL, mixed lineage leukemia (MLL), myelodysplastic syndrome, myeloproliferative neoplasm or chronic myeloid leukemia were eligible. Eligibility in the two expansion cohorts: 90 mg/m2 (n = 17) and 54 mg/m2 (n = 6), was restricted to pts with MLL-r or MLL-partial tandem duplication (MLL-PTD). Pinometostat was given via continuous intravenous infusion (CIV) for 21 of 28 day cycles in the dose escalation phase and CIV for 28 of 28 day cycles in the expansion phases, until disease progression or unacceptable toxicity. All pts underwent serial collection of PK and peripheral blood mononuclear cells (PBMC) for PD. Leukemic blasts were isolated from PBMCs using flow cytometry and quantified for dimethylation of H3K79 (H3K79-me2) by ChIP-Seq. Results: As of 28-June-2015, 49 pts have enrolled in the dose escalation and expansion phases. Pts receiving 21/28 day infusions: 12 (n=1), 24 (n=5), 36 (n=4), 54 (n=6) and 80 mg/m2/day (n=3). Pts receiving 28/28 day infusions: 54 (n=6) and 90 mg/m2/day (n=24). Table 1. Patient Characteristics n (%) Median age, yrs (range) 51 (19 - 81) Sex (M / F) 27/22 Diagnosis MLL-r* 29 (59) AML MLL-PTD** 5 (9) MLL-wt 7 (14) ALL MLL-r* 5 (10) MLL-wt 1 (2) MLL MLL-r 1 (2) CMML MLL-r 1 (2) # of prior therapeutic regimens 1 - 2 29 (59) 3 - 4 18 (36) >4 2 (4) Prior allogeneic hematopoietic cell transplant 20 (41) * centrally confirmed by karyotype/FISH ** centrally confirmed by NGS (next generation sequencing) Adverse events (AEs) reported in >15% of pts regardless of attribution were: nausea, constipation, vomiting, abdominal pain, diarrhea, hypocalcemia, hypokalemia, hypomagnesemia, fatigue, fever, peripheral edema, mucositis, febrile neutropenia, leukocytosis, anemia, cough, dyspnea, and pneumonia. Grade ≥3 non-hematologic related toxicities include: hypophosphatemia (n=1), decreased ejection fraction (n=3), or elevated transaminases (n=1). Nine patients had leukocytosis (absolute monocyte and neutrophil 50% above baseline and above upper limit of normal) or differentiation. The median days of pinometostat treatment was 35 days (range 3-189 days). To date, objective responses observed are morphologic CR (1 pt), cytogenetic CR (MLL negative by FISH) (1 pt), PR (1 pt) and resolution of leukemia cutis (3 pts). Dose proportional PK was observed with rapid attainment of steady-state plasma concentrations (Css) on Day 1 of treatment. Plasma Css correlated with inhibition of global H3K79-me2 in PBMCs. H3K79-me2 ChIP-Seq demonstrated pinometostat induced reductions in methylation at MLL -r target genes HOXA9 and MEIS1 (median inhibition = 61%: range = 13-91%) in all 9 pts analyzed to date from the 90 mg/m2 expansion cohort. Inhibition of H3K79-me2 in leukemic blasts is consistent with DOT1L suppression. PK-PD relationships in both expansion cohorts using both free and total plasma Css are being explored. Conclusions: Pinometostat administered as a CIV to adults with R/R leukemia has an acceptable safety profile. Clinical activity as demonstrated by both marrow responses and resolution of leukemia cutis were observed. In addition, analysis of H3K79-me2 by ChIP-Seq demonstrated PD reductions in the methylation of MLL-r target genes following pinometostat exposure, as expected from DOT1L inhibition. Relationships between PK exposure, reductions in pinometostat induced H3K79-me2 levels and clinical response are being interrogated. Disclosures Stein: Seattle Genetics: Consultancy; Agios Pharmaceuticals: Consultancy. Rizzieri:Teva: Other: ad board, Speakers Bureau; Celgene: Other: ad board, Speakers Bureau. Berdeja:Novartis: Research Funding; Takeda: Research Funding; BMS: Research Funding; Curis: Research Funding; MEI: Research Funding; Abbvie: Research Funding; Onyx: Research Funding; Array: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Acetylon: Research Funding. Altman:Novartis: Other: Advisory board; Spectrum: Other: Advisory board; Ariad: Other: Advisory board; Seattle Genetics: Other: Advisory board; BMS: Other: Advisory board; Astellas: Other: Participation in an advisory board December 2013. Thomson:Epizyme, Inc: Employment. Blakemore:Epizyme: Employment. Daigle:Epizyme, Inc: Employment. Fine:Epizyme: Employment. Waters:Epizyme, Inc: Employment. Armstrong:Epizyme, Inc: Consultancy. Ho:Epizyme, Inc: Employment.