ALBERT

Description: BACKGROUND: Symptom burden in essential thrombocythemia (ET) and polycythemia vera (PV) is severe even among individuals with low risk disease (Blood 2012. 12;123(24):3803-10). New therapies exist which alleviate the severe symptom burden and reduce splenomegaly in ET and PV patients (N Engl J Med 2015; 372:426-435). This analysis is the first to date to evaluate thresholds at which symptom-based treatment can be considered for ET and PV patients who are intolerant or resistant to hydroxyurea (HU). METHODS: Patient demographics, symptom burden, and disease traits were collected from ET and PV patients at a single time point during therapy. The MPN-10 total symptom score (TSS, JCO 2012;30(33)4098-103) was utilized to assess symptom burden. Symptom criteria models were determined as previously described among a population of MF patients (Scherber et. al. EHA 2016: a2250). Cutoffs were then evaluated in a cohort of ET and PV patients to assess for utility as a symptom model among this population. RESULTS: Demographics and symptom burden: 838 PV and 867 ET patients with previous hydroxyurea therapy were included in this analysis. Patients were of mean age (54.9 years ET, 64.0 years PV) and gender (69.2% female ET, 55.7% female). Mean disease duration was 6.0 years for ET and 7.3 years for PV.Among ET and PV patients, 15.0% and 24.2% had prior thrombosis respectively. In evaluating prognostic risk, ET patients tended to be low (45.5%) or intermediate risk (42.9%) with only a minority of patient meeting criteria forhigh risk disease (11.6%). Laboratory findings: ET patients had a mean platelet value of 598.7x 109/L(SD=283.4). Among PV patients, mean hematocrit was 45.8% (SD=8.1) and 42.6% of patients had a hematocrit of greater than 45%. White blood cell count was normal between the two groups (ET mean 8.3 x 109/L, PV mean 9.0 x 109/L). Symptoms: Mean worst symptom severity was 6.4 out of 10 (SD=2.7). Among ET patients, worst symptom was most frequently fatigue (32.7%, mean 5.0/10, SD=3.1, overall prevalence 88%) followed by night sweats (13.6%, mean 2.0/10, SD=3.0, overall prevalence 53%) and concentration difficulties (8.6%, mean 3.1/10, SD=3.0, overall prevalence 68%). For PV, worst individual symptom items were most frequently fatigue (29.2%, mean 5.2/10, SD=3.0, overall prevalence 91%), pruritus (14.1%, mean 3.2/10, SD=3.2, overall prevalence 69%), and night sweats (12.8%, mean 2.5/10, SD=3.0, overall prevalence 57%). Cutoff Scoring: 47.0% of ET patients fit criteria for TSSgreater than to equal to 20; 59.0%% had a single itemgreater than 5; and 45.7% had both a TSS greater than or equal to 20 and a single item greater than 5. Among PV participants, 54.5% had aTSS greater than to equal to 20; 66.1% had a single itemgreater than 5; and 51.5% had both a TSS greater than or equal to 20 and a single item greater than 5. Each scoring method was significantly associated with individual item scores (Table 1). Prognostic scoring was not significantly associated with any of the symptom cutoffs evaluated. Correlations: Among ET patients, a prior history of thrombosis was significantly associated with having a worst symptom item greater than 5 (p=0.043). ET patients with lower hemoglobin were significantly more likely to meet criteria for a MPN-10 score greater than or equal to 20 or to meet combined criteria for a MPN-10 greater than or equal to 20 and single worst item greater than 5 (for both p=0.01 or less). For PV, lower hematocrit levels were significantly associated with having an individual worst symptom score of greater than 5 (44.9% versus 46.7%, p=0.0376). CONCLUSION: Assessment of ET and PV symptoms, now measurable through standardized and practical instruments such as the MPN-10, is an integral part of determining therapeutic impact of newer therapies in both clinical practice and trial settings. In our modeling, patients with severe symptom burden profiles are well represented by utilizing cutoff criteria including aworst individual symptom item of greater than 5 out of 10, an MPN-10 score of greater than or equal to 20, or combined criteria of both cutoffs. These cutoffs can be considered when determiningwhich HU intolerant or resistant patients would most benefit fromsymptom orientedtreatment. Disclosures Kiladjian: AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding. Schouten:Novartis: Consultancy; Sanofi: Consultancy. Etienne:BMS: Speakers Bureau; ARIAD: Speakers Bureau; Pfizer: Speakers Bureau; novartis: Consultancy, Speakers Bureau. Harrison:Incyte Corporation: Honoraria, Speakers Bureau; Shire: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Baxaltra: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses, Research Funding, Speakers Bureau. Radia:Pfizer: Honoraria; Novartis: Honoraria. Cervantes:AOP Orphan: Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mesa:Promedior: Research Funding; Celgene: Research Funding; CTI: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy.

Description: Background: The Philadelphia chromosome negative chronic myeloproliferativeneoplasms (MPNs) including essential thrombocythemia (ET), polycythemia vera(PV), and myelofibrosis (MF) are a group of diseases of myeloid clonal lineage with significant symptom burden. MPN patients have also been found to have a high likelihood of mood disturbance related to their MPN, including symptoms of depression and anxiety (BMC Cancer. 201616:167). To date, the relationship between disease factors and depressive symptoms among MPN patients has not been well characterized. Methods: We have previously published the results of a 70-item internet-based survey which evaluated fatigue-relieving strategies among MPN patients (Cancer. 2016 Feb 1;122(3):477-85). Surveyed data included mental health questionnaires including a measure of symptoms of depression, the PHQ-2, (Ann Fam Med. 2010. 8(4): 348-353), a measure of positive and negative moods the POMS-short form (J Nerv Ment Dis. 1979;167(10):612-4) and a measure of symptoms of depression and anxiety, the MHI-5 (J Consult Clin Psychol. 1983. 51;730-742). This abstract is a secondary analysis of data collected among this cohort. Data: Demographics A total of 1788 individuals diagnosed with an MPN participated in the survey. 1389 patients answered questions regarding mood and psychological comorbidities. Many MPN patients reportedthat they had been seen by a health provider for care or diagnosis of depression (32%), anxiety (29.5%), stress (26.2%), or grief(15.0%). Overall, 24.0% of ET, 22.2% of PV, and 22.9% of MF patients endorsed symptoms of depression based on their score of greater than or equal to 3 on the PHQ-2. Demographic and Psychosocial Correlates Younger patients were significantly more likely to have PHQ-2 score of equal to or greater than three (57.0 years vs 59.5 years, p=0.0006). Gender, race, and country of origin did not significantly correlate with screening positive for symptoms of depression. Higher BMI was associated with a higher likelihood of screening positive for symptoms of depression (BMI 26.2 vs 24.6, p=0.005). Not surprisingly, having received treatment for mood problems in the last 6 months (p

Description: Objectives: Primary central nervous system lymphoma (PCNSL) is a rare aggressive B-cell lymphoma, particularly in HIV-negative individuals, that represents a clinical challenge due to its location and lack of comprehensive molecular and biologic description. Histopathologic features are that of diffuse large B-cell lymphoma with expression of pan-B-cell markers as well as cell of origin (COO) germinal center B cell (GCB) and post-germinal center B cell (non-GCB) markers. Previous studies using immunohistochemistry (IHC) suggest that the majority of PCNSL cases are non-GCB. However, gene expression profiling has revealed non-GCB to be comprised of two distinct subtypes, namely activated B-cell (ABC) and unclassified (UNC) subtypes that are indistinguishable by IHC. To date COO testing using the highly accurate Lymph2Cx gene expression profiling assay has not been reported in PCNSL. Methods: IRB approval was obtained and HIV negative patients diagnosed with PCNSL, who had given informed consent and for whom archived tumor tissue was available for testing were identified. COO testing was performed using the Lymph2Cx NanoString assay on RNA extracted from formalin-fixed, paraffin embed tissues using our established laboratory protocols. Clinical data including patient demographics, lines of treatment and survival outcomes were collected and correlated with each other and Lymph2Cx COO results. Results: Thirty-two HIV-negative patients diagnosed between January 2005 and June 2015 were included. Median age was 61 years (30-82) and 53% were male. Radiographic information was available for 18/32 patients. Eleven (61%) had a single brain lesion at diagnosis, while 7 (39%) had 〉1 brain lesion. Lines of systemic therapy were 1 (91%) and 2 (9%). All patients received methotrexate-based induction therapy (44% received methotrexate, rituximab and temozolomide, 16% received single-agent methotrexate, 31% received methotrexate and rituximab, and 9% received the modified Bonn regimen; methotrexate and cytarabine-based induction). A total of 10 patients (31%) received high-dose chemotherapy and autologous stem cell transplant (ASCT) for consolidation. Of the 10 patients that underwent consolidation therapy, 9 underwent ASCT after first line induction, and 1 underwent ASCT after second line therapy. None of the patients received whole-brain radiation therapy. At a median follow-up of 29 months (range of 2-107) median event-free survival (EFS) was 16.3 months (95% CI, 8.8-45.7), and median overall survival (OS) was 41.2 months (95% CI, 28.5-NE). COO testing using the Lymph2Cx assay revealed that 91% (29/32) were ABC, 9% (3/32) were GCB, and none were UNC. Histopathology reports described COO using the Hans algorithm in 11 of the 32 cases. Of the 3 determined to be GCB on Lymph2Cx, 1 was denoted GCB by the Hans algorithm and 2 were not stained to determine COO. Of the 29 determined to be ABC by Lymph2Cx, 9 were denoted non-GCB and 1 was denoted GCB by the Hans algorithm, and 19 were not stained to determine COO. Conclusions: This series of HIV-negative patients with PCNSL showed median survival consistent with previous studies. In this first series using the Lymph2Cx assay, we confirmed that over 90% of PCNSLs are of ABC subtype, which concurs with previous reports that PCNSL tumors are predominately non-GCB by the Hans algorithm. These findings provide biological rationale forthat pharmacologic interventions targeting B-cell receptor signaling to be explored in clinical trials in the majority of patients with PCNSL. Figure. Figure. Disclosures Rimsza: NanoString: Other: Inventor on the patent for the Lymph2Cx assay.

Description: Background: Pegylated interferon alpha-2a (Peg INF2a) has been demonstrated to be active therapy for high-risk essential thrombocythemia (ET), polycythemia vera (PV), and early myelofibrosis (MF). We retrospectively analyzed the outcomes of Peg INF2a therapy in myeloproliferative (MPN) patients treated outside the constraints of a clinical trial. Methods: Charts were analyzed for demographic and clinical data. Toxicity to therapy was assessed per CTCAE 3.0 criteria. Therapeutic responses for ET and PV were calculated by the revised ELN/IWG-MRT criteria including complete remission (CR), partial resmission (PR), no response (NR), or progressive disease (PD). Responses in MF were calculated by EUNMET: complete response (CR), major response (MR), moderate response (MoR), minor response (MiR) and NRand the revised IWG-MRT/ELN criteria: CR, PR, clinical improvement (CI), stable disease (SD) or PD. Results: Patients: 75 patients were identified overall. There were 36 PV patients (48%), 20 ET patients (26.7%), and 19 MF patients (25.6%). Thirteen MF patients were post-PV/ET MF. The median age at diagnosis was 51.5 yrs (range 28.8-75.1). JAK2 V617 mutation was present in 53 patients (70.7%). Median baseline hemoglobin (g/dL), leukocyte (x10 9), and platelet count (x109) for PV was 13.6, 8.6, 369, for ET was 12.5, 6.8, 517, and for MF was 11.4, 8.0, and 420, respectively. DIPSS risk category for the 19 MF patients: Low in 6 (31.5%) patients, Intermediate-1 in 3 (15.7%), Intermediate-2 in 8 (42%), and High in 2 (10.5%) patients. The majority of patients (82.2%) had received at least one prior cytoreductive therapy for their disease. Therapy: Median starting dose of Peg INF2a was 45 micrograms/week (range 45-90). The median peak dose was 90 micrograms/week (range 45-270). The median tolerated dose was 60 micrograms/week (range 5.6-180). The median duration of treatment was 24 months (range 3.6-85). Toxicity: Overall the Peg INF2a was well tolerated. Hematological toxicity included: leukopenia at grade 1 in 13 patients (17.3%), grade 2 in 5 patients (6.7%), and grade 3 in 1 patient (1.3%), anemia at grade 1 in 10 patients (13.3%) and grade 2 in 1 patient (1.3%), thrombocytopenia at grade 1 in 13 patients (17.3%) and grade 2 in 1 patient (1.3%). The most common non-hematologic toxicity included: fatigue at grade 1 in 14 patients (18.7%) and grade 2 in 4 patients (5.3%), transaminitis at grade 1 in 6 patients (8%) and grade 2 in 3 patients (4%), myalgias at grade 1 in 4 patients (5.3%). Response: See Table #1 PV/ET: 56 patients were evaluated by ELN/IWG-MRT criteria overall: A complete remission (CR) was seen in 8 patients (14.3%), a partial remission (PR) in 18 patients (32.1%), either a CR or PR in 18 patients (32.1%) when histologic remissions were unable to be documented due to lack of restaging bone marrow examination, no response in 11 patients (19.6%), and progressive disease in 1 patient (1.8%). Of the 12 patients receiving at least1 phlebotomy per month, 10 patients (83.3%) became phlebotomy independent with therapy. Of the 20 ET patients, 12 patients (60%) had platelet normalization (

Description: Treatment of polycythemia vera (PV) with the Murine Double Minute 2 (MDM2) antagonist, idasanutlin, in a phase 1 trial was reported by our group to be well tolerated with a high overall response rate (Mascarenhas et al, Blood. 2019 Jun 5). A global, phase 2 trial is currently underway evaluating idasanutlin in hydroxyurea (HU) resistant/intolerant PV patients (NCT03287245). MDM2, a negative regulator of TP53 is upregulated in PV CD34+ cells and inhibition of MDM2 targets PV hematopoietic stem/progenitor cells (HSPC) (Lu et al, Blood. 2014;124(5):771-90). Additional trials of MDM2 antagonists have shown promise, however, there is concern that these agents have the potential to induce TP53 mutations or promote expansion of TP53 mutated clones. Resistance to MDM2 inhibitors has been evaluated in solid tumor cell lines and attributed to either the emergence of de novoTP53 mutations or the selection of TP53 mutated clones. (Michaelis et al, Cell Death Dis. 2011;2:e243; Skalniak et al, Cancers. 2018;10(11)). The effect of MDM2 inhibition on TP53 mutant clones is of particular interest in myeloproliferative neoplasms (MPNs). TP53 mutations have been reported with a low allele burden in ~15% of chronic MPN patients (Kubesova et al, Leukemia. 2018;32(2):450-61), however, TP53 loss of heterozygosity and rapid expansion of TP53 mutant clones is associated with transformation to blast phase (Lundberg et al, Blood 2014,123:2220-8). As reported, in the idasanutlin PV trial, 1/13 patients were identified to have a baseline pathogenic TP53 mutation in hematopoietic cells (VAF 5.5%), using a deep sequencing assay with a limit of detection (LOD) of VAF 0.5%. This patient was a non-responder to idasanutlin and upon treatment had an increasing JAK2V617F and TP53 mutant VAF. End of study hematopoietic cell specimens of all patients were deep sequenced (LOD 0.1%) and revealed that 4 additional patients harbored detectable TP53 mutations after idasanutlin treatment with VAF ranging from 1-12%. In each sample, 1-5 unique TP53 mutations were identified, all within the hotspot domain of the TP53 gene. Deeper sequencing of baseline and follow-up samples revealed these mutations were present at a subclonal level (VAF 0.1-5.5%) and increased over time, indicating that treatment with the MDM2 antagonist promoted expansion of already existing TP53 mutant clones (Table 1, Figure 1). None of the patients who lacked a TP53 mutation at baseline developed a TP53 mutant clone with idasanutlin treatment. There was no clear association of presence of TP53 mutations with prior HU, anagrelide or interferon exposure. There has been careful monitoring of patients to determine whether the expanding TP53 clone has clinical ramifications. Patients were on study for a median of 54 weeks (23-131). The only patient who exemplified resistance to idasanutlin was the single patient with a high burden TP53 mutation (37%). All other patients were taken off study due to patient choice/toxicity. Furthermore, all TP53 mutant and non-mutant patients have had stable disease with no evidence of progression to MF or AML. Sequencing of 2 patients post-discontinuation of idasanutlin revealed that the VAF of the TP53 mutant clones decreased since the agent was discontinued. Updated patient molecular data post-treatment discontinuation will be reported at the meeting. To investigate whether idasanutlin induces de novo TP53 mutations in PV myeloid cells we performed long term HSPC cultures. Mononuclear cells from 6 distinct PV patients were treated continuously with idasanutlin (500 nM) over ~6 weeks and DNA from both treated and untreated colonies were analyzed using next generation sequencing with a LOD of 2% VAF and no TP53 mutations were detected. The combined in vitro and clinical data reveals that treatment with an MDM2 antagonist is not associated with the emergence of de novoTP53 mutations but rather the expansion of prior existing TP53 clones. This does not appear to have clinical repercussions, however, close monitoring of these patients is essential. We recommend that patients be screened for TP53 mutations prior to treatment with an MDM2 antagonist and that if present the TP53 mutant VAF be followed during their treatment course. Resistance to MDM2 inhibition is likely dependent on the TP53 mutant VAF and further studies will need to clarify the ideal dosing schedule of MDM2 antagonists and/or combinatorial therapy to prohibit TP53 mutant clonal expansion. Disclosures Houldsworth: Cancer Genertics: Other: stock in; Sema4: Employment. Rossi:Sema4: Employment. Kiladjian:AOP Orphan: Honoraria, Research Funding; Celgene: Consultancy; Novartis: Honoraria, Research Funding. Rampal:Agios, Apexx, Blueprint Medicines, Celgene, Constellation, and Jazz: Consultancy; Constellation, Incyte, and Stemline Therapeutics: Research Funding. Mascarenhas:Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Roche: Consultancy, Research Funding; Merck: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI Biopharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Promedior: Research Funding; Merus: Research Funding; Pharmaessentia: Consultancy, Membership on an entity's Board of Directors or advisory committees. Hoffman:Merus: Research Funding.

Description: Dexamethasone is a powerful anti-inflammatory, immunosuppressive agent widely used in the treatment of MM with pleiotropic effects on both the tumor, and host immune cells. We report on a completely novel approach to immune modulation using an agent with almost directly opposite effects to glucocorticoids on innate immune cells. LCL161 is an IAP antagonist targeting the cellular inhibitor of apoptosis proteins cIAP1 and -2 (cIAP1/2) that in a phase I study in solid tumors was well tolerated with a cytokine release syndrome as the dose limiting toxicity. We previously reported that loss of cIAP1/2 in MM cells results in the stabilization of NIK and activation of the non-canonical NFkB pathway, a pathway we found frequently activated by a promiscuous array of mutations in multiple myeloma (MM). As expected, we found that LCL161 has no direct anti-tumor activity against MM cells in vitro and ex vivo. However, the non-canonical NFkB pathway is also a key activator of the innate immune response. Remarkably, we found that in vivo LCL161 has dramatic, apoptosis-independent activity associated with marked phagocytosisagainst MM that develops spontaneously in an immunocompetent genetically engineered mouse model of MM (Vk*MYC). Cyclophosphamide (Cy), which has been shown to induce an acute secretory activating phenotype in tumor-associated macrophages, markedly potentiated the anti-tumor effects of LCL161. We show that phagocytes (depleted by liposomal clodronate), but not adaptive immune cells, are required for the anti-tumor effect. Consistently we show that LCL161 activates dendritic cells and macrophages in vitro, and in vivo, and upregulates production of inflammatory cytokines. A phase 2 clinical trial of LCL161 was conducted in 24 patients with relapsed MM previously exposed to both IMiDs and PIs, but less than 5 prior lines of therapy. Patients received LCL161 1200mg po weekly, with Cy 500mg po weekly added for progressive disease or lack of response. Single agent LCL161 was well-tolerated, with grade 3 or 4 non-hematologic toxicity in four patients, and following the addition of cyclophosphamide in 9 patients. No patients responded to single agent LCL161, and the best response was stable disease in 6/24. In 21 patients, Cy was added after a median of 2 cycles, in whom the best response was stable disease or better in 18/21 (p

Description: 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] p0.30 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 p0.50 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.

Description: Background: Post polycythemia vera (PV) and essential thrombocytosis (ET) myelofibrosis (MF), like primary MF (PMF), are heralded by splenomegaly, cytopenias, heavy symptom burden, and decreased overall survival. Risk prognostication tools, including the dynamic international prognostic scoring system (DIPSS) and the Passamonti risk score for post-PV MF (Passamonti et al. Blood 2010, 2008), are helpful to estimate survival and guide therapeutic decision-making. For Post-PV/ET MF, it is unknown if DIPSS correlates with the Passamonti risk score. Here we evaluate the correlation between the two available risk prognostication tools in post-PV/ET MF. Methods: Retrospective chart review conducted for patients with post-PV/ET MF seen between 2000-2012. Descriptive statistics were used to describe patient demographic and clinical variables in post PV/ET patients. DIPSS Score: calculated at time of last follow up: 1 point for age 〉65, 2 points for hemoglobin 25 x 109, 1 point for circulating blasts 1% and 1 point for constitutional symptoms. Risk group was assigned: low-risk (0 adverse points), intermediate-1 risk (1 adverse point), intermediate-2 risk (2-3 adverse points) and high-risk (4-6 adverse points). Passamonti Risk Scores: calculated at time of last follow up: with 1 point assigned for hemoglobin level less than 100 g/L (10 g/dL), platelet count less than 100 x10 (9)/L, and/or leukocyte count more than 30x10(9)/L. Cross-tabulation of DIPSS score versus Passamonti risk score at time of last follow-up was conducted and the percent agreement was described. Spearman correlation coefficient between DIPSS score at follow-up with Passamonti score was conducted. Results: Patients: Sixty-one (58%) post-ET and 44 (42%) post-PV patients were identified, total N=105. Male to Female ratio was 1:1. Median age was 65 (range 25-87). JAK2 V617Fpresent in 68 (65.4%). Median hemoglobin was 10.9 g/dL (range 5.3-17.0), median platelet count 287 x 109 (range 20-1864), and median WBC was 11.1x 109 (range 1.1-165). Risk prognostication: When DIPSS risk scores were applied 11 patients were low, 48 patients were Intermediate-1, 31 patients were Intermediate-2, and 10 patients were high. When Passamonti risk scores were applied 57 patients received score of 0, 31 patients scored 1, 9 patients scored 2, and 3 patients scored 3. DIPSS and Passamonti risk score agreement: The overall agreement between DIPSS and Passamonti risk scores was low, with 24% of cases in agreement. Spearman correlation: Rho=0.451; p

Description: Background: Hypomethylating agents (HMA) such as 5-Azacitidine (Aza) have overall responses rate of ~35-50% in acute myeloid Leukemia (AML) and higher risk myelodysplastic syndrome (MDS) patients (pts). However, eventually all pts develop resistance on therapy. To improve upfront response rates and to address HMA failure, we performed genome-scale RNAi screens targeting genes on chromosomes 5 and 7, recurrent cytogenetic abnormalities in AML/MDS. These screens identified Hedgehog pathway (Hh) genes as potentially targetable vulnerabilities with Aza. Combination experiments with smoothened (SMO) inhibitors (SMO is a central activating gene within the Hh pathway) showed pre-clinical synergy. These and additional published data support the Hh pathway as a targetable vulnerability in AML, and provide a rational for a trial. Methods: A phase I/Ib protocol of the oral SMO inhibitor LDE225 (Sonidegib) in combination with Aza in untreated and relapsed/refractory (rel/ref) AML, chronic myelomonocytic leukemia (CMML), MDS, or MDS/myeloproliferative neoplasm overlap pts. Objectives of the phase I part are to determine safety, toxicity and MTD and for the phase Ib part to assess the preliminary overall efficacy. Sonidegib was started at dose level (DL) 0 at 400mg oral daily continuously and Aza at the approved doses (75mg/m2 x 7 days or days 5-2-2) with dose adjustment per label. A classical 3+3 design was used and DLT (CTCAE v4.0) defined as 〉 grade 3 CPK elevation or hepatic or non-hematologic adverse events (AEs) lasting 〉 7 days or any grade 4 event, except for hematologic toxicities. DLT was assessed after 42 days when steady-state concentrations of Sonidegib were reached. Pharmacokinetic assessments were not performed for this study. Results: Patients and Dose Levels : Between 5/22/2014 and the data cut-off date (7/20/2015), 36 pts were enrolled. Median age was 72 y (range 52-85 y) and 64% were male. Most AML pts (23 of 24) had intermediate or unfavorable cytogenetics and most MDS/CMML pts were in the int.- to high-/very high-risk group (IPSS-R). Six pts were treated at DL-0 of Sonidegib 400mg/day and one DLT of CPK elevation was observed. Another patient had grade 4 neutropenia (which at the time was included in the DLT definition, later removed). Due to overall tolerance of the combination at DL 0 and investigator assessment, despite only 1/6 pts having a formal DLT, DL -1 at Sonidegib 200mg was explored at which 0/3 pts (1 pt non-evaluable) had DLT and the phase Ib portion was opened at DL -1. To date a total of 24 AML (13 newly dx, 11 rel/ref), 11 MDS/CMML (5 newly dx, 6 rel/ref ) and 1 myelofibrosis pt have been enrolled. Safety and Tolerability: An initial safety and efficacy assessment for 25 of the 29 pts treated on the phase Ib (n=26) + the MTD cohort of 200 mg (n=3) and for who at least 2 cycles of treatment follow up was available, showed that all pts experienced at least one grade-3 or 4 hematologic AE with a lower rate in the untreated vs. treated cohort. Other, non-hematologic grade-3 and 4 AEs respectively were seen in 24 and 28% of patients-most commonly hyponatremia and fatigue, known AEs for this drug class. Treatment delays occurred in 28% of pts and Aza or Sonidegib dose reductions in 16%. 23 (79%) pts are alive and 6 have died (21%), with one death while pt was actively treated but was deemed unrelated; 11 pts remain on study, with the remainder showing disease progression (n=3) or taken-off study for other reasons (n=3 each for AEs and did not want further treatment; n=4 other). Efficacy : As of 7/20/15 with a median treatment duration of 2 cycles, 2/5 untreated MDS/CMML pts achieved CR/CRi; 1 HMA rel/ref AML had CR; 1 untreated AML pt each had PR and MLFS. 90% of pts have not progressed. Updated results will be presented at the ASH 2015 meeting; by then all 29 pts will have completed a minimum of 4-6 cycles on study and full efficacy and AE result on all pts will be reported. To date the OS at 6 mo is 77% (95% CI: 44-97%) with a median PFS of 4 mo (range: 2-NR). Many pts in the untreated cohorts have just enrolled. Conclusion: Hh pathway inhibition with the clinically well tolerated SMO inhibitor Sonidegib in combination with Aza in MDS and AML pts is well tolerated with mostly hematologic AEs as expected with early signs of clinical activity in untreated and HMA-failure pts. Full efficacy results of 29 pts and updated safety data will be reported for this first combination trial of a SMO inhibitor in combination with a HMA in MDS and AML pts. Disclosures Mesa: Gilead: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Incyte Corporation: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Promedior: Research Funding; NS Pharma: Research Funding; CTI Biopharma: Research Funding. Al-Kali:Novartis: Research Funding.