Mesa, Ruben A.

Abstract The lysine deacetylase inhibitor suberoylanilide acid (SAHA) exhibits promising but limited activity in the treatment of acute myeloid leukemia (AML). To identify potential targets for rational combination therapies that increase the efficacy of SAHA in AML, we performed a functional RNA-interference (RNAi) drug modifier screen to identify genes that, when inhibited, potentiate or antagonize the in vitro anti-leukemic activity of SAHA. A total of 901 kinase, phosphatase and closely associated signaling genes were silenced in TF-1, HEL and THP-1 cells, with four different siRNA sequences per gene, both alone and in combination with SAHA treatment. Screen hit lists for each cell line were over-laid on an integrated functional relationship network. A community detection algorithm was then applied to this sub-network and siRNA sensitive modules were identified. Each module represents a highly connected set of genes in the integrated network. To identify pathways represented by each module, enrichment was evaluated using the National Cancer Institute (NCI) Protein Interaction Database (PID) pathways. Both cell line-specific and universal sensitizing targets, grouped into a small number of pathways, emerged from these screens. Seven pharmacologic inhibitors interfering with these pathways have been assessed in a panel of four or five AML cell lines, including SET-2, TF-1, HEL, THP-1, and OCI-AML3. Of the seven tested inhibitors targeting SAHA sensitizing networks, one combination exhibiting universal SAHA sensitization in all AML cell lines tested was further assessed in drug dose response assays using ex vivo cultures of bone marrow mononuclear cell populations derived from patients with various myeloid malignancies. The combination demonstrated “one-sided” SAHA EC50 fold-enhancement, as well as strong synergy by “two-sided” CalcuSyn combination index determination in all ex vivo specimens examined to date (N=6), including polycythemia vera (PV), chronic myelomonocytic leukemia (CMML), myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) overlap syndrome, MDS transformed to AML, and de novo AML samples. Thus, this first reported large-scale SAHA RNAi modifier screen in AML has identified a specific pathway/target whose inhibition broadly synergizes with HDAC inhibition in myeloid malignancies. A novel compound putatively targeting this respective pathway/target is currently in early clinical development and has shown limited single-agent activity. With the full dataset presented, we will propose a novel rational combination to enhance the activity of HDAC inhibition in AML and other myeloid malignancies that could be translated into design of a clinical trial. Disclosures: No relevant conflicts of interest to declare.

Abstract Introduction: Myelofibrosis (MF) is a life-threatening hematologic malignancy characterized by splenomegaly and debilitating symptoms including fatigue, abdominal pain, night sweats, bone pain, pruritus, and unintentional weight loss. The myeloproliferative neoplasm symptom assessment form (MPN-SAF) is a PRO tool designed to measure MF-related symptom burden and was developed and validated at Mayo Clinic. It was modified (MPN-SAF total symptom score [TSS] and TSS 2.0) for use in the PERSIST-1 and PERSIST-2 phase 3 trials. For PERSIST-1, when examining the 6 common symptoms in both TSS versions (tiredness, night sweats, early satiety, itchiness, bone pain, and abdominal pain), pacritinib-treated patients (pts) had significant improvements in TSS overall and in individual symptoms vs BAT; Pt Global Impression of Change (PGIC) was also significantly improved for pts receiving pacritinib. Improvements in EORTC-QLQ-C30 scales were noted in the pacritinib arm (Mesa, EHA 2015). The proportion of pts achieving spleen volume reduction (SVR) ≥35% at Week 24 was significantly greater with pacritinib vs BAT (ITT: 19.1% vs 4.7%, p=0.0003; evaluable at baseline and Week 24: 25.0% vs 5.9%; p=0.0001). This analysis examines relationships between TSS improvement and changes in splenomegaly and HRQoL outcomes. Methods: Pts who received no prior JAK inhibitor therapy were randomized 2:1 to oral pacritinib 400 mg once daily or BAT. Pts were stratified by DIPSS risk (Int-1/Int-2 vs High) and platelet count (<50,000/μL vs 50,000/μL to <100,000/μL vs ≥100,000/μL). Pts must have had a baseline total TSS ≥13 using MPN-SAF TSS 2.0. Each symptom is rated on a scale from 0 (absent) to 10 (worst imaginable) using MPN-SAF TSS and TSS 2.0. Results for the 6 symptoms common to both TSS versions are reported. Additional PROs used for assessment of HRQoL included EORTC QLQ-C30 and EQ-5D-5L. In multivariate logistic regressions, odds of TSS reduction ≥50% at Week 24 were modeled as a function of Week 24 SVR ≥35%, spleen length reduction (SLR) ≥ 50%, PGIC, improvement in each EORTC scale, and improvement in EQ-5D-5L Overall Health State (OHS) and in each dimension individually while adjusting for treatment (pacritinib vs BAT). Correlations were examined in all pts and by baseline platelet counts (<50,000/μL, <100,000/μL, and ≥100,000/μL). Results: A total of 327 pts were enrolled (PAC: 220, BAT: 107). 62% of pts had primary MF, 32% had baseline platelets <100,000/μL, and 16% had baseline platelets <50,000/μL. TSS reduction ≥50% was found to be associated with SVR ≥35% and improvement in splenomegaly (SLR ≥50%). In the total pt population, there was a significant association between TSS reduction and SVR (odds ratio [OR]=2.60, p=0.016). In all pts, there was a significant association between TSS reduction and improvements in OHS as measured by EQ-5D-5L (OR=2.30, p=0.013). TSS reductions were also marginally associated with improvements in the QLQ-C30 Global Health Scale (GHS)/QoL Scale (OR=1.92, p=0.050) and, though not statistically significant, there was a trend of improvement in perceived overall health as measured by PGIC (OR=2.16, p=0.118). TSS reductions were further examined in pts grouped by baseline platelet count. Improvement in EQ-5D-5L OHS was marginally associated with TSS reductions in pts with platelets <50,000/μL (OR=6.03, p=0.057). For pts with platelets <100,000/μL, reductions in TSS were significantly associated with reductions in splenomegaly (SLR ≥50%; OR=9.53, p=0.004), and improvements in the QLQ-C30 GHS/QoL domain (OR=4.03, p=0.022) as well as the EQ-5D-5L OHS (OR=5.49, p=0.008). A significant association between TSS reductions and SVR ≥35% was observed in pts with platelets ≥100,000/μL (OR=3.99, p=0.005). In all pts, improvements in Fatigue as measured by QLQ-C30 were significantly associated with TSS reductions (OR=2.20, p=0.019) as well as in pts with baseline platelets <50,000/μL (OR=17.88, p=0.008) and <100,000/μL (OR=10.18, p<0.001). Conclusions: In the total pt population, TSS reduction was associated with improvements in spleen response and perceived overall health. This trend was also observed in pts with low baseline platelet counts. Additionally, TSS reduction was significantly associated with improvements in fatigue, a major contributor to poor HRQoL in pts with MF. This reinforces the clinical relevance of measuring TSS using a validated instrument as an endpoint in MF trials. Disclosures Mesa: NS Pharma: Research Funding; Pfizer: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding; CTI Biopharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Genentech: Research Funding; Promedior: Research Funding. Off Label Use: This abstract discusses off-label use of pacritinib. Harrison:Shire: Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Gilead: Honoraria; CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau. Cervantes:Novartis: Consultancy, Speakers Bureau; Sanofi-Aventis: Consultancy; CTI-Baxter: Consultancy, Speakers Bureau. Dean:CTI Biopharma: Employment, Equity Ownership. Wang:CTI Biopharma: Employment, Equity Ownership. Yang:Baxalta: Employment, Other: Stock. 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.

Abstract Abstract 5053 Background: The Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) is a concise instrument of patient reported outcomes (PRO) designed to assess the unique spectrum of symptoms present in the majority of patients (Mesa et. al. Cancer 2007). We sought to validate the Swedish Translation of the MPN-SAF which addresses 19 separate symptoms reported by MPN patients. Methods: We utilized the standard practice of PRO translation in which 3 independent translations are created by 3 independent translators fluent in both languages. A fourth translator then discussed the translations with the other translators and a consensus translation was obtained. Patients self completed the MPN-SAF: Swedish at the time of a physician office visit and the Swedish EORTC-QLQ-C30 was co-administered for validation purposes. Results: Patients and Symptomatic Burden: 114 patients were prospectively enrolled (ET (N=53; 47%), PV (N=53; 47%) and MF (N=8; 6%)) a median of 6 years (range:0-42) from their diagnosis. Patients were of a median age (68; range 27–88 years) and gender (53% females) typical of the disease. 78% (N=88) had received some form of non-aspirin medical therapy for their disease, and 75% were on therapy at the time of completing the questionnaire. Patients frequently had a history of either thrombotic events (26%) and/or hemorrhagic events (10%). The MPN-SAF measured 19 items in the enrolled patients (data summarized in Table 1). Validation Analysis: EORTC-QLQ-C30 Consistent with our experience with the MPN-SAF:English Pearson correlations between MPN-SAF-Swedish individual symptom scores and the Swedish EORTC-QLQ C30 showed excellent correlations with co-validation questions including fatigue, pain, headache, insomnia, early satiety, and sad mood (all p<0.001). Correlations with EORTC-QLQ-C30 subscales demonstrated excellent correlations between MPN-SAF measurements and corresponding subscales. Comparison with Mpn-Saf:English: Comparison with 102 patients prospectively completing the MPN-SAF: English (ET=20, PV=N=23, MF=59) showed (when adjusting for MPN subtype) excellent correlation with all but 3 items in which the prevalence of the symptoms was similar but the severity less in the Swedish cohort (early satiety, headache and impaired quality of life). Additionally, the ranking of the prevalence of symptoms was very well correlated between both cohorts when controlling for disease type. Conclusions: The MPN-SAF: Swedish is an easy to administer, clear, 19 item inventory of patient reported outcomes that is specific to MPNs. Additionally, the instrument is validated by 1) comparison to previously validated Swedish Instruments and 2) the correlation with the MPN-SAF:English. Utilization of the instrument in Swedish MPN clinical trials will allow for useful comparison to patients completing the MPN-SAF in other countries. Disclosures: Samuelsson: Roche Sweden: Mesa: SBio: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Incyte: Research Funding; Roche: Research Funding; eisai: Research Funding; telik: Research Funding.

Abstract Introduction: Most myelofibrosis (MF) patients develop anemia during evolution of the disease process predicting decreased survival. Previous studies exploring the effect of danazol for the treatment of anemia in MF demonstrate responses in anemia. In prior randomized-controlled studies, ruxolitinib demonstrated improvements in splenomegaly, symptom burden, and even survival yet improvements in cytopenias were uncommon. We designed a phase II multicenter pilot study to evaluate the efficacy and tolerability of combination therapy with ruxolitinib and danazol in MF patients with anemia. Methods: This was a Simon optimum two-stage phase II trial. Eligible subjects received ruxolitinib, a JAK 1/JAK2 inhibitor, at 10mg (plat >75 x10x9) BID or 5mg (plat <75 x10 x9) BID) representing initial dose reduction for JAK inhibitor naïve patients to minimize cytopenias, in combination with tapered danazol up to 200mg orally TID. Dose escalation was allowed after completion of 28 days for lack of response or for disease progression. Pts without progression continued for 6 cycles at 56 days each. Treatment modifications were allowed for either medication based on emergent adverse events (AE). Treatment responses were evaluated every cycle by IWG-MRT criteria (Blood 2006). Patient reported outcome questionnaires (MPN-SAF, EORTC QLQ-C30) were administered at baseline, prior to treatment cycles, and at study discontinuation. Results: Patients: Fourteen pts enrolled (9 Mayo Arizona, 5 Mount Sinai). Median (Med) age 70.5 (range 43-78), M:F ratio 1.8:1. Ten primary MF, 2 post-essential thrombocythemia MF, and 2 post-polycythemia vera MF. JAK2 V617F positive in 42.9%. DIPSS Low in 1 pt, Int-1 in 1pt, Int-2 in 8 pts, High in 2 pts, and unknown in 2pts. Transfusion dependence in 35.7% at baseline. Med baseline hemoglobin (hgb) was 9.0 g/dL (R: 8.3 - 12.4), platelet (plt)157 x109/L (R:143 - 520). Thirteen pts received prior therapy, with 9 pts (64.2%) on a JAK inhibitor within 3 months of study entry. Tolerability: Nine pts (64.2%) ended active treatment, due to progression of disease in 2 pts (22.2%), adverse event (AE) in 2, pt preference in 2, stem cell transplant in 1, unrelated death in 1, and comorbidity in 1. Med duration of therapy: 91 days (range 24-287). AEs regardless of attrition included: hematologic grade 3 or >: anemia in 7 pts (50%), neutropenia in 2 (14.3%), leukopenia in 1 (7.1%), and thrombocytopenia in 2 (14.3%). Non-hematologic grade 3 or >: electrolyte abnormalities in 3 pts (21.4%), infection in 2 (14.3%), edema in 1(7.1%), hypertension in 1 (7.1%), and intracranial hemorrhage in 1 (7.1%). Efficacy: Of the 5 JAK inhibitor naïve pts, 4 had stable or increasing hgb levels with therapy despite new ruxolitinib therapy. Of the 9 pts on prior JAK inhibitor (5 ruxolitinib, 4 other), 5 (55.5%) and 7 (77.7%) patients had stable or increasing hgb or plt levels, respectively. See Table #1. Four pts (28.6%) had at least 50% improvement from baseline on MPN-SAF TSS (95% CI 8.4%-58.1%). Overall treatment response: (IWG-MRT) stable disease (SD) in 10 pts (71.4%), clinical improvement (CI) in 3 (21.4%) all of which were spleen responses, and progressive disease (PD) in 1 (7.1%). Trial was halted secondary to lack of anemia response. Table 1. Patient Specific Response Patient IWG-MRT Response: Study Cycles (N): Prior therapy (within 3 mo) Hemoglobin Response*: (initial, final g/dL) Platelet Response*: (initial, final 10(9)/L) Ruxolitinib 1 CI-Spleen 5 D (8.8, 7.6) S (221,212) 2 SD 4 D (10.3,7.9) S (54,46) 3 SD 2 S (8.8,8.9) S (82,101) 4 SD 3 I (8.9,9.8) S (441,458) 5 SD 3 S (9.6, 9.5) I (161, 231) JAK Inhibitor: 6 SD 5 Momelotinib S (9.0, 9.2) S (132,113) 7 SD 1 NS-018 D (8.3, 7.1) D (120,43) 8 SD 3 NS-018 D (10.1,9.0) D (138,111) 9 SD 2 LY2784544 S (8.7,9.1) S (56,21) Other: 10 CI-Spleen 9 Procrit I (10.5,11.9) S (153,198) 11 CI-Spleen 7 None I (8.9,10.2) D (338,133) 12 PD 1 Hydroxyurea S (12.4, 12.2) D (310, 82) 13 SD 1 Procrit D (10.1, 8.6) D (192, 71) 14 SD 1 Hydroxyurea S (9.1,8.9) D (346,119 *S=stable (Hgb +/- 0.5g/dL, Plt +/- 50x109, D=decreasing, I=increasing. Conclusions: Although overall well tolerated, the addition of danazol to ruxolitinib therapy has modest incremental efficacy by IWG-MRT criteria. Clinical improvement was observed in 21.4% of treated patients, however responses were limited to spleen reduction. The degree to which danazol may stabilize expected cytopenias is interesting and may require further investigation. Disclosures Hoffman: Promedior: Research Funding; Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees; All Cells, LLC: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mesa:Gilead: Research Funding; Genentech: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; CTI Biopharma: Research Funding; Pfizer: Research Funding; Promedior: Research Funding; NS Pharma: Research Funding; Incyte Corporation: Research Funding.

Abstract Background: Myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms (MPNs). Patients across all 3 MPNs experience marked disease burden in terms of symptoms and negative effects on quality of life (QoL), productivity, and activities of daily living (ADL). To improve the lives and health of patients with MPNs, it is also important to have a current understanding of these burdens from a financial standpoint. This analysis of MPN Landmark survey data examined the financial burden of patients who reported that their MPN affected their employment (ie, reduced work hours, discontinued employment, or went on medical disability) or experienced no such effects on their employment. Methods: Patients diagnosed with MF, PV, or ET were recruited to participate in a real-world retrospective study (MPN Landmark survey) in the US (fielded May - July 2014). Only respondents who were diagnosed before 2013 and were 16 to 65 years of age at the time of diagnosis were eligible for this analysis. Participants were asked if their MPN had an impact in terms of reduced work hours, discontinued employment, medical disability, or no impact; the first 3 categories were not mutually exclusive. Participants provided information on their annual household income in 2013 before taxes by selecting from the following categories: ≤$15,000, $15,001-$25,000, $25,001-$35,000, $35,001-$50,000, $50,001-$75,000, $75,001-$100,000, and >$100,000. The mid value of each range was used to calculate mean income levels within each subgroup evaluated. Results: A total of 813 patients completed the web-based Landmark survey and 369 eligible patients were included in this analysis (MF, 85; PV, 172; ET, 112). Median age among patients with ET was slightly lower than among patients with MF and PV at time of MPN diagnosis (ET, 48 years; MF, 56 years; PV, 53 years). The majority of respondents were women (MF, 62%; PV, 52%; ET, 75%). Almost all patients (99%) had health insurance, primarily group commercial insurance through an employer (MF, 46%; PV, 53%; ET, 57%) and Medicare (MF, 40%; PV, 34%; ET, 24%). Most patients had at least some college education (ie, some college, 4-year degree, or postgraduate degree): MF, 86%; PV, 90%; ET, 88%. The mean 2013 household income of patients with MF, PV, and ET were similar to each other ($79,800, $80,200, and $80,400, respectively) and slightly higher than the total 2013 US mean household income of $75,839. A notable proportion of patients in each MPN group reported that their disease led to reduced work hours, discontinued employment, and medical disability: MF, 38%, 35%, and 33%, respectively; PV, 33%, 28%, and 15%; ET, 28%, 21%, and 4%. Patient demographics, such as age and health insurance status, were similar among patients who reported MPN-associated effects on employment and patients who did not within each MPN. In each MPN group, the mean percentage household income loss in patients with reduced work hours, discontinued employment, and medical disability were: MF, 16%, 18%, and 28%, respectively; PV, 15%, 24%, and 17%; and ET, 0%, 24%, and 37%, compared with patients who did not experience any effects of their MPN on employment (Figure 1). Discontinued employment and medical disability tended to have a greater impact compared with reduced work hours across MPNs. Conclusion: Patients withMPNs may experience a considerable negative impact on their employment status, which in turn may be associated with reduced annual household income. Therefore, across all MPNs, forestalling or reversing discrete aspects of the diseases that negatively impact individual productivity is an important factor in the management of these chronic neoplasms. Disclosures Parasuraman: Incyte Corporation: Employment, Equity Ownership. Naim:Incyte Corporation: Employment, Equity Ownership. Paranagama:Incyte Corporation: Employment, Equity Ownership. Thyne:Incyte Corporation: Speakers Bureau. Mascarenhas:Incyte Corporation: Research Funding; Novartis Pharmaceuticals Corporation: Research Funding; Promedior: Research Funding; Roche: Research Funding; CTI Biopharma: Research Funding; Kalobios: Research Funding. Mangan:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees. Fazal:Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau; Ariad: Consultancy, Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau. Miller:Incyte Corporation: Honoraria, Research Funding. Mesa:Promedior: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding; NS Pharma: Research Funding; CTI Biopharma: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Genentech: Research Funding; Pfizer: Research Funding.

Abstract Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2). OBJECTIVE: The purpose of this study is to determine the safety, tolerability and efficacy of orally administered NS-018 in patients with PMF, post-PV MF, or post-ET MF. METHODS: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, post-PV MF, or post-ET MF. The study drug, NS-018, was given orally either daily (QD) or twice daily (BID) in 28-day cycles. In Phase 1, changes in spleen size were assessed by manual palpation, quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF), and responses were assessed according to the IWG-MRT/ELN consensus criteria. Bone marrow fibrosis (BMF) was evaluated by biopsy, according to WHO criteria. Changes in grade of BM fibrosis from baseline were categorized as improvement, stabilization, or worsening. The Phase 1 portion of the study has been completed and data are presented here. RESULTS: In this Phase 1 study, 48 patients were enrolled across 10 dosing cohorts (75-400 mg QD/100-400 mg BID). Characteristics: 37 PMF, 5 post-PV MF, 6 post-ET MF with a median age (range) 69.5 yrs (38-83); M/F:29/19; 35 JAK2V617F+, and 23 previously treated with a different JAK2 inhibitor. At 400 mg QD/BID, NS-018 dosing was associated with drug-related neurologic adverse events (AEs) including dizziness, peripheral neuropathy, headache, disturbance in attention, vertigo, dysesthesia, paresthesia, aphasia, and nervous system disorder (not otherwise specified). The 300 mg QD dose was better tolerated than 250 mg BID or 300 mg BID, with fewer neurologic AEs, and was selected as the recommended phase 2 dose (RP2D). For the 48 phase 1 patients, reductions in MF-SAF score were observed for all symptoms after 3 cycles, including for patients with prior JAK2 inhibitor treatment. In all dose cohorts, ≥ 50% patients achieved ≥ 50% score reduction from baseline in night sweats, pruritus and bone pain after 1 cycle. Moreover, ≥ 50% patients achieved ≥ 50% score reduction from baseline in abdominal pain and inactivity after 3 cycles. In patients who had received prior JAK2 inhibitor, ≥ 50% patients achieved ≥ 50% score reduction from baseline in filling up quickly, inactivity, night sweats and quality of life after 3 cycles. Among 36 patients with baseline splenomegaly ≥ 5 cm and treatment for ≥ 1 cycle, 20 (56%) showed ≥ 50% reduction in spleen size (confirmed for ≥ 8 weeks in 16 patients), including 9/19 (47%) patients with prior JAK2 treatment. According to IWG criteria, 14/36 (39%) patients showed splenic clinical improvement (CI) for ≥ 8 weeks, 4 had hemoglobin CI, and 1 had platelet CI. After 3 cycles of NS-018 treatment, 11/31 (37%) evaluable patients had a reduction in bone marrow fibrosis(BMF) by ≥ 1 grade. At any time during NS-018 treatment, 17/31 (55%) evaluable patients had a reduction in BMF by ≥ 1 grade. Overall, 23% (7/31) patients maintained improvement in BMF for ≥ 12 weeks. Reduction in BMF after 3 cycles was correlated with reduction in splenomegaly and hemoglobin responses. To date, 8 patients with prior JAK inhibitor treatment have been enrolled into the phase 2 portion of the trial. Updated Phase 2 data will presented at the meeting. CONCLUSIONS: The RP2D dose of NS-018 was 300 mg QD. This dose provided an acceptable safety and tolerability profile, and reduction in symptomatic splenomegaly. Phase 2 is ongoing and includes patients previously treated with other JAK2 inhibitors. Disclosures Talpaz: ARIAD: Research Funding; Bristol-Myers Squibb: Research Funding; Sanofi Aventis: Research Funding; Pfizer: Research Funding; Incyte: Research Funding. Ritchie:Incyte: Speakers Bureau; Celgene: Speakers Bureau. Odenike:Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Algeta Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Suneisis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; Geron: Research Funding. Jamieson:GlaxoSmithKline: Research Funding; Johnson & Johnson: Research Funding. Stein:Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis Pharmaceuticals Corporation: Consultancy; Pfizer: Research Funding; CTI Biopharma: Research Funding; NS Pharma: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding; Promedior: Research Funding; Genentech: Research Funding.

Abstract Background: Patients with polycythemia vera (PV) have an increased symptom burden (eg, fatigue, pruritus, and splenomegaly-related symptoms) and an increased risk of mortality compared with the general population, often resulting from thrombotic events, disease transformation to myelofibrosis, or secondary malignancies. There are limited data regarding PV burden and treatment patterns in a contemporary, real-world US setting. REVEAL is an ongoing observational study being conducted to describe contemporary demographics, burden of disease, clinical management, patient-reported outcomes, and healthcare resource utilization among patients with PV in the US. The objective of this assessment is to describe the clinical characteristics at enrollment among patients currently enrolled in REVEAL (enrollment from July 22, 2014 to June 9, 2015). Methods: REVEAL is a multicenter, noninterventional, nonrandomized, prospective, observational study. Eligible patients are ≥18 years of age with a PV diagnosis and currently under active management by a physician in the US. Data regarding disease and clinical characteristics, patient-reported outcomes, and health resource utilization are being collected at usual-care visits over a planned 36-month observation period. Analyses of these preliminary data were descriptive. Results: At data cutoff, 865 patients were enrolled (total planned enrollment, n=2000) from 174 sites (academic, n=27; community, n=147). Median (range) age at enrollment was 67 (22-95) years, 55.5% were male, 89.5% were white, and 45.4% had a history of smoking. Most patients (99.4%) had health insurance, including Medicare (56.0%), PPO (24.3%), or HMO (11.6%). Fifty-two percent were retired, 29.6% were employed, and 4.5% were unable to work or disabled. A total of 40.2% of patients completed a college/graduate degree, 19.9% had some college, and 32.5% completed high school or the equivalent. Documented major World Health Organization diagnostic criteria included JAK2V617F mutation in 50.9% of patients, elevated hemoglobin in 52.3%, and red cell mass in 5.5%. A bone marrow biopsy was conducted in 24.0% of patients, approximately half of whom (52.4% of the 24.0%) had trilineage myeloproliferation. Erythropoietin levels were abnormal in 19.7% of patients. Approximately half (46.6%) of patients had physician-reported PV-related symptoms at diagnosis, most frequently fatigue (25.2%) and pruritus (14.0%). At enrollment, median disease duration was 52.6 months; 42.3% of patients were diagnosed ≥5 years before enrollment. The most common comorbidities were hypertension (51.3%), obesity (14.2%), dyspnea (13.4%), myalgia (11.2%), and diabetes mellitus (11.1%). Mean hematocrit was 44.9%, hemoglobin was 14.5 g/dL, white blood cell count was 11.4×109/L, platelet count was 363.7×109/L, and absolute neutrophil count was 363.7×109/L. Twenty-one percent of patients had a history of thrombotic events, with 13.1% and 8.6% of patients experiencing ≥1 venous or arterial thromboembolic event, respectively. Of the 261 reported thrombotic events, 43.7% occurred after diagnosis of PV. The most common PV symptoms recorded at enrollment (using the Myeloproliferative Neoplasm Symptom Assessment Form) were fatigue (37.1%), pruritus (24.0%), headache (18.6%), insomnia (17.0%), dizziness (13.2%), bone pain (10.5%), and blurred vision (7.9%); 19.7% of 518 evaluable patients had palpable splenomegaly. Fewer than half of patients were receiving aspirin at enrollment (47.7%). The most common PV treatments ± aspirin were phlebotomy (PBT; 63.5%), hydroxyurea (HU; 42.2%), watchful waiting (5.3%), and ruxolitinib (3.1%); 23.0% of patients received PBT + HU. Conclusion: The REVEAL study is unique in that it captures data from both academic and community centers, and therefore includes a broader segment of the PV population typically not described in the literature. REVEAL can provide novel insights into questions related to the contemporary demographics of PV, practice patterns regarding diagnosis and therapy, and the real-world burden of PV and its impact on patients' quality of life and work productivity. Preliminary descriptive data from this early subset of patients suggest that a high proportion of patients report having PV-related symptoms at diagnosis, fewer patients are treated with aspirin than expected, and that thromboembolic event rates remain high after diagnosis. Disclosures Stein: Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees. Moliterno:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees. Boccia:Incyte Corporation: Honoraria. Naim:Incyte Corporation: Employment, Equity Ownership. Cordaro:Incyte Corporation: Employment, Equity Ownership. Peng:Incyte Corporation: Employment, Equity Ownership. Sun:Incyte Corporation: Employment, Equity Ownership. Parasuraman:Incyte Corporation: Employment, Equity Ownership. Mesa:Promedior: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; NS Pharma: Research Funding; CTI Biopharma: Research Funding; Gilead: Research Funding; Pfizer: Research Funding; Incyte Corporation: Research Funding; Genentech: Research Funding.

Abstract Introduction: The myeloproliferative neoplasms (MPNs) including polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF) are rare diseases which contribute to significant morbidity. Symptom management is a prime objective in MPN treatment but current symptom assessment tools have not been validated compared to the general population. Materials and Methods: The MPN Symptom Assessment Form (MPN-SAF) is a reliable and validated clinical tool used to assess MPN symptom burden. The MPN-SAF was administered to MPN patients (n=106) and, for the first time, General Practice and non-blood relative/family controls (n=124) as part of a UK pilot case-control study. Mean scores for individual MPN-SAF items and for the Total Symptom Score were previously compared between cases and controls adjusting for potential confounding variables (Anderson LA, et al. Am J Hematol. 2015). The current analysis employed linear discriminant analysis (a multivariate technique) to compare MPN-10 symptom profiles between controls and cases, and between controls and patient groups by MPN diagnosis (ET n=55, PV n=37, PMF n=14). Results: MPN patients as a single group had significantly different MPN-10 symptom profiles compared to controls (multivariate analysis of variance [MANOVA] p<0.001). Discriminant loadings which represent correlations between each individual MPN-10 item and the single significant canonical variable were >0.30 for all MPN-10 items, and >0.50 for weight loss, fatigue, night sweats, bone pain, abdominal discomfort, inactivity, concentration problems, and itching. This suggests that all MPN-10 items contribute to distinguishing between patients and controls. The linear discriminate function correctly categorized 72% of all subjects. When considering patients by diagnosis, MPN-10 symptom profiles significantly differed across patients with ET, PV, and PMF and controls (MANOVA p<0.001). Three canonical variables were significant, with discriminant loadings of the first canonical variable being >0.50 for the same MPN-10 items as the previous analysis; of the second canonical variable for fever; and of the third canonical variable for bone pain. This suggests that MPN-10 items are broadly useful in differentiating between patients and controls, with particular symptoms (e.g., fever and bone pain) contributing to differentiating between patients with different diagnoses. The linear discriminate function correctly categorized 58% of all subjects. Conclusions: MPN patients experience significant morbidity when compared to the general population highlighting the need to manage symptoms effectively. Symptom profiles can not only distinguish MPN patients from general population participants, but also distinguish among patients with ET, PV, and PMF. The results further validate the use of the MPN-SAF as a discriminatory tool to assess MPN symptomatic disease burden. The MOSAICC Study team acknowledges the support of the National Institute for Health Research, through the Northern Ireland Cancer Research Network (NICRN) and for Southampton the Central South Coast Cancer Network (CSCCN). Disclosures Mesa: Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.

Abstract Introduction: There are few effective treatment options available for patients (pts) with myelofibrosis (MF). Pts with thrombocytopenia, a risk factor for shorter overall survival, have poorer prognosis (Gangat, J Clin Oncol 2010). Pacritinib is a kinase inhibitor with specificity for JAK2, FLT3, IRAK1, and CFSR1 and has demonstrated minimal myelosuppression in clinical trials (Hart, Leukemia 2011; Komrokji, Blood 2015; Mesa, ASCO 2015). In the phase III open-label PERSIST-1 trial, a significantly greater proportion of pts treated with pacritinib achieved spleen volume reductions (SVR) ≥35% vs BAT (ITT: 19.1% vs 4.7%, p=0.0003; pts evaluable at baseline and Week 24: 25.0% vs 5.9%, p=0.0001; Mesa, ASCO 2015). This analysis examines pt responses across subgroups. Methods: Pts naive to treatment with JAK inhibitors were randomized 2:1 to receive oral pacritinib 400 mg once daily or BAT. Stratification factors included DIPSS risk status and baseline platelet count. Pts were eligible who had DIPSS Intermediate (Int)-1, Int-2, or High risk disease; absolute neutrophil count >500/µL; palpable splenomegaly ≥5 cm; and baseline Total Symptom Score (TSS) ≥13 using the Modified MPN Symptom Assessment Form Total Symptom Score (MPN-SAF TSS and TSS 2.0). There was no restriction on baseline platelets or hemoglobin (Hgb) levels. The primary endpoint was the proportion of pts achieving SVR ≥35% at Week 24 by centrally-reviewed MRI or CT and the secondary endpoint was the proportion of pts achieving ≥50% reduction in TSS from baseline at Week 24 using 6 symptoms from the MPN-SAF TSS. Pt responses were analyzed by baseline risk factors for MF including platelet counts (<50,000/µL vs ≥ 50,000/µL and <100,000/µL vs ≥100,000/µL), sex, age (≥65 y vs <65 y), JAK2V617F mutation status (positive vs negative), baseline MF diagnosis (primary MF [PMF] vs secondary MF), reticulin and collagen fibrosis staging (> 1 vs ≤1), TSS (≥20 vs <20), white blood cell count (>25×109/L vs ≤25×109/L), peripheral blasts (≥5% vs <5%), Hgb (<10 g/dL vs ≥10 g/dL), transfusion dependency by Gale criteria (Y vs N), time from diagnosis (<12 mos vs ≥12 mos), ECOG PS (2-3 vs 0-1), and bone pain (>3 vs ≤3). In multivariate logistic regressions, the odds of SVR ≥35% and TSS reduction ≥50% at Week 24 were modeled as a function of prognostic factors for MF and adjusted for treatment (pacritinib vs BAT). Results for the 6 symptoms common to both TSS versions are reported. Results: 327 pts were enrolled and randomized (pacritinib: 220, BAT: 107). Overall, 62% of pts had PMF; 32% had baseline platelets <100,000/µL and 16% had <50,000/µL; 75% were positive for JAK2V617F. After a median follow-up of 8.4 months, treatment with pacritinib resulted in consistent rates of SVR across subgroups (Figure 1). When comparing vs BAT, the greatest differences in SVR ≥35% rates between treatment arms were observed in pts with baseline platelets <50,000/μL (+22.9% vs BAT), JAK2V617F-negative pts (+23.0% vs BAT) and those aged <65 y (+21.2% vs BAT). Improvements in TSS (TSS and TSS 2.0 reduction ≥50%) were also consistent for pts receiving pacritinib (Figure 2). By multivariate analysis, SVR ≥35% was significantly correlated only with ECOG PS ≥2 (odds ratio [OR]=2.97, p=0.030) and TSS reduction ≥50% was significantly correlated only with bone pain >3 (OR=0.35, p=0.004). Conclusions: Treatment with pacritinib resulted in consistent rates of SVR ≥35% and TSS reduction ≥50% irrespective of baseline characteristics. Comparisons vs BAT were favorable for all patient subpopulations examined for both endpoints. These results support the use of pacritinib across all intermediate- or high risk MF pt subgroups analyzed. Figure 1. Proportion of Patients Receiving PAC who Achieved ≥35% SVR from baseline to Week 24 (95% CI) Figure 1. Proportion of Patients Receiving PAC who Achieved ≥35% SVR from baseline to Week 24 (95% CI) Figure 2. Proportion of Patients Receiving PAC who Achieved ≥50% TSS reduction (6 common symptoms in MPN-SAF TSS and MPN-SAF TSS 2.0) from baseline to Week 24 (95% CI) Figure 2. Proportion of Patients Receiving PAC who Achieved ≥50% TSS reduction (6 common symptoms in MPN-SAF TSS and MPN-SAF TSS 2.0) from baseline to Week 24 (95% CI) Disclosures 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. Off Label Use: This abstract discusses off-label use of pacritinib. Mesa:Gilead: Research Funding; NS Pharma: Research Funding; Incyte Corporation: Research Funding; Genentech: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Promedior: Research Funding; Pfizer: Research Funding; CTI Biopharma: Research Funding. Cervantes:Novartis: Consultancy, Speakers Bureau; Sanofi-Aventis: Consultancy; CTI-Baxter: Consultancy, Speakers Bureau. Prasad:BIOGEN IDEC: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Speakers Bureau. Elinder:Celgene: Consultancy. Recher:Sunesis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Chugai: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. te Boekhorst:CTI Biopharma: Consultancy; Novartis: Consultancy. Somervaille:Novartis Pharmaceuticals Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees. Dean:CTI Biopharma: Employment, Equity Ownership. Harrison:Shire: Speakers Bureau; Gilead: Honoraria; CTI Biopharma: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau.

Abstract Abstract 1280 Poster Board I-302 Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) including polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF) are defined as clonal hematopoietic stem cell disorders. These disorders show an inherent tendency for transformation into leukemia (MPN-blast phase) which is hypothesized to be accompanied by acquisition of additional genomic lesions. We, therefore, obtained a comprehensive profile of genomic alterations associated with leukemic transformation by using single-nucleotide polymorphism (SNP) array in 88 MPN patients, as well as 71 cases with MPN-blast phase, and correlated these findings with their clinical parameters. A relatively high number of genomic alterations was found in MPN after leukemic transformation with 4.6 ± 0.6 abnormalities per sample compared to only 1.4 ± 0.2 changes per patient in chronic phase (p<0.001). Compared to the cytogenetic data, SNP-chip analysis detected about 47% additional chromosomal changes in the MPN samples, and 31% more in the MPN-blast phase cases, whereas SNP-array allelokaryotyping practically captured all cytogenetic abnormalities in our study population. Several additionally altered regions were detected in patients with MPN-blast phase compared to chronic phase, including both deletion and copy-number neutral-loss of heterozygosity (CNN-LOH) on chromosome 12p (9%) and 21q (9%), involving ETV6 and RUNX1. Notably, deletion and CNN-LOH on 17p involving TP53 were diagnosed in 18% of MPN-blast phase samples, which was highly associated with preceding treatment with alkylating agents (p=0.016). Moreover, trisomy 8, as well as amplification of 8q24.21 involving the MYC gene, were detected in 13% of patients with MPN-blast phase who were almost exclusively negative for the JAK2V617F mutation. Genome-wide inspection of further critical regions with promising new candidate genes involved in the evolution to the MPN-leukemic phase included deletion and CNN-LOH on 7q22.1 (SH2B2) in 18%, duplication/amplification on 19p13.2 (PIN1, ICAM1, CDC37) in 13% and 21q22.2 (ERG) in 9% of MPN patients with blast crisis. In contrast, we detected a decreased frequency of JAK2V617F in MPN-blast phase samples (52%) compared to chronic phase (71%). Also, the percentage of patients with homozygous mutant JAK2 as a result of CNN-LOH was lower in the MPN-blast phase (43%) compared to the chronic phase (53%). Taken together, the data suggest that gain-of-function mutation of JAK2 is not a perquisite for leukemic transformation. Remarkably, CNN-LOH on either 7q or 9p was related to decreased survival after leukemic transformation (p=0.02 and p=0.012, respectively). Given the variety of allelic imbalances, our data suggest that MPN-blast phase appears to be a heterogeneous disease prone to have evolved multiple mechanisms to provide a proliferative advantage to the abnormal leukemic clone. Our analysis of MPN genomes in the chronic compared to the leukemic stage provided new prognostic insights, as well as novel causative genes which might be involved in the transformation to MPN-blast phase. Disclosures No relevant conflicts of interest to declare.