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PURPOSE Recent trials have shown potential benefit of extended adjuvant endocrine therapy and relatively high risk of recurrence (RoR) after 5 years in hormone receptor-positive (HR+) human epidermal growth factor receptor 2–negative (HER2−) breast cancer. Although risk of late relapse in HR+ HER2− breast cancer is fairly well defined, the risk in HER2-positive (HER2+) breast cancer treated with adjuvant trastuzumab-based chemotherapy remains largely unknown. METHODS We included 3,177 patients with HER2+ breast cancer treated with adjuvant chemotherapy alone or with trastuzumab from the North Central Cancer Treatment Group N9831 (ClinicalTrials.gov identifier: NCT00005970 ) and National Surgical Adjuvant Breast and Bowel Project B-31 (ClinicalTrials.gov identifier: NCT00004067 ) trials. RESULTS Overall, HR+ breast cancer was significantly associated with improved recurrence-free survival (RFS) during the first 5 years (hazard ratio, 0.65; 95% CI, 0.56 to 0.77; P < .001). Among patients treated with trastuzumab, cumulative hazard for RFS was lower in patients with HR+ HER2+ breast cancer during the first 5 years (10.96% v 17.48%; hazard ratio, 0.60; 95% CI, 0.45 to 0.79; P < .001). However, there was no significant difference in RFS based on HR status during years 5 to 10 (hazard ratio, 1.32; 95% CI, 0.93 to 1.88; P = .12). A comparable degree of trastuzumab benefit was observed in HR+ and HR− breast cancers ( P for interaction = .87). Furthermore, we observed low RoR in years 5 to 10 among patients with HR+ HER2+ breast cancer: 3.23% in patients without lymph node involvement (N0) and 6.39% in patients with involvement of one to three lymph nodes (N1). CONCLUSION The benefit of adjuvant trastuzumab persists for a long time. A distinct pattern of recurrence was observed between HR+ and HR− HER2+ disease but with similar degree of benefit from adjuvant trastuzumab. RoR in years 5 to 10 in HR+ HER2+ breast cancer is low, particularly in patients with N0 or N1 disease.

44 Background: A noninvasive cfDNA blood test detecting multiple cancers at earlier stages could decrease cancer mortality. In earlier discovery work, whole-genome bisulfite sequencing outperformed whole-genome and targeted sequencing approaches for multi-cancer detection across stages at high specificity. Here, multi-cancer detection and TOO localization using bisulfite sequencing of plasma cfDNA to identify methylomic signatures was evaluated in preparation for clinical validation, utility, and implementation studies. Methods: 2301 analyzable participants (1422 cancer [ > 20 tumor types, all stages], 879 non-cancer) were included in this prespecified substudy from the Circulating Cell-free Genome Atlas (CCGA) (NCT02889978) study - a prospective, multi-center, observational, case-control study with longitudinal follow-up. Plasma cfDNA was subjected to a targeted methylation sequencing assay using high-efficiency methylation chemistry to enrich for methylation targets, and a machine learning classifier determined cancer status and tissue of origin (TOO). Observed methylation fragments characteristic of cancer and TOO were combined across targeted regions and assigned a relative probability of cancer and of a specific TOO. Results: Performance is reported at 99% specificity (ie, a combined false positive rate across all cancer types of 1%), a level required for population-level screening. Across cancer types, sensitivity ranged from 59 to 86%. Combined cancer detection (sensitivity [95% CI]) was 34% (27-43%) in stage I (n = 151), 77% (70-83%) in stage II (n = 171), 84% (79-89%) in stage III (n = 204), and 92% (88-95%) in stage IV (n = 281). TOO was provided for 94% of all cancers detected; of these, TOO was correct in > 90% of cases. Conclusions: Detection of multiple deadly cancers across stages using methylation signatures in plasma cfDNA was achieved with a single, fixed, low false positive rate, and simultaneously provided accurate TOO localization. This targeted methylation assay is undergoing validation in preparation for prospective clinical investigation as a cancer detection diagnostic. Clinical trial information: NCT02889978.

Abstract Despite its efficacy, chimeric antigen receptor T-cell therapy (CART) is limited by the development of cytokine release syndrome (CRS) and neurotoxicity (NT). While CRS is related to extreme elevation of cytokines and massive T cell expansion, the exact mechanisms for NT have not yet been elucidated. Preliminary studies suggest that NT might be mediated by myeloid cells that cross the blood brain barrier. This is supported by correlative analysis from CART19 pivotal trials where CD14+ cell numbers were increased in the cerebrospinal fluid of patients that developed severe NT (Locke et al, ASH 2017). Therefore, we aimed to investigate the role of GM-CSF neutralization in preventing CRS and NT after CART cell therapy via monocyte control. First, we investigated the effect of GM-CSF blockade on CART cell effector functions. Here, we used the human GM-CSF neutralizing antibody (lenzilumab, Humanigen, Burlingame, California) that has been shown to be safe in phase II clinical trials. Lenzilumab (10 ug/kg) neutralizes GM-CSF when CART19 cells are stimulated with the CD19+ Luciferase+ acute lymphoblastic leukemia (ALL) cell line NALM6, but does not impair CART cell function in vitro. We have found that malignancy associated macrophages reduce CART proliferation. GM-CSF neutralization with lenzilumab results in enhanced CART cell antigen specific proliferation in the presence of monocytes. To confirm this in vivo, NOD-SCID-g-/- mice were engrafted with high disease burdens of NALM6 and treated with low doses of CART19 or control T cells (to induce tumor relapse), in combination with lenzilumab or isotype control antibody. The combination of CART19 and lenzilumab resulted in significant anti-tumor activity and overall survival benefit compared to control T cells (Fig 1A), similar to mice treated with CART19 combined with isotype control antibody, indicating that GM-CSF neutralization does not impair CART cell activity in vivo. This anti-tumor activity was validated in an ALL patient derived xenograft model. Next, we explored the impact of GM-CSF neutralization on CART cell related toxicities in a novel patient derived xenograft model. Here, NOD-SCID-g-/- mice were engrafted with leukemic blasts (1-3x106 cells) derived from patients with high risk ALL. Mice were then treated with high doses of CART19 cells (2-5x106 intravenously). Five days after CART19 treatment, mice began to develop progressive motor weakness, hunched bodies, and weight loss that correlated with massive elevation of circulating human cytokine levels. Magnetic Resonance Imaging (MRI) of the brain during this syndrome showed diffuse enhancement and edema, associated with central nervous system (CNS) infiltration of CART cells and murine activated myeloid cells. This is similar to what has been reported in CART19 clinical trials in patients with severe NT. The combination of CART19, lenzilumab (to neutralize human GM-CSF) and murine GM-CSF blocking antibody (to neutralize mouse GM-CSF) resulted in prevention of weight loss (Fig 1B), decrease in critical myeloid cytokines (Fig 1C-D), reduction of cerebral edema (Fig 1E), enhanced leukemic disease control in the brain (Fig 1F), and reduction in brain macrophages (Fig 1G). Finally, we hypothesized that disrupting GM-CSF through CRISPR/Cas9 gene editing during the process of CART cell manufacturing would result in functional CART cells with reduced secretion of GM-CSF. We designed guide RNA targeting exon 3 of the GM-CSF gene and generated GM-CSFk/o CART19 cells. Our preliminary data suggest that these CARTs produce significantly less GM-CSF upon activation but continue to exhibit similar production of other cytokines and exhibit normal effector functions in vitro (Fig 1H). Using the NALM6 high tumor burden relapse xenograft model as described above, GM-CSFk/o CART19 cells resulted in slightly enhanced disease control compared to CART19 cells (Fig 1I). Thus, modulating myeloid cell behavior through GM-CSF blockade can help control CART mediated toxicities and may reduce their immunosuppressive features to improve leukemic control. These studies illuminate a novel approach to abrogate NT and CRS through GM-CSF neutralization that also potentially enhances CART cell functions. Based on these results, we have designed a phase II clinical trial using lenzilumab as a modality to prevent CART related toxicities in patients with diffuse large B cell lymphoma. Disclosures Ahmed: Humanigen: Employment. Sahmoud:Humanigen: Employment. Durrant:Humanigen: Employment. Russell:Vyriad: Equity Ownership. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Acerta: Research Funding. Kenderian:Novartis: Patents & Royalties; Tolero Pharmaceuticals: Research Funding; Humanigen: Research Funding.

Abstract Despite the remarkable outcomes and recent FDA approval of CD19 directed chimeric antigen receptor T (CART19) cell therapy in B cell malignancies, the durable responses in diffuse large B cell lymphoma are less than 40% and CART activity in chronic lymphocytic leukemia (CLL) is further limited. This is thought to be related to loss of CART persistence, poor trafficking to lymph nodes and inhibition by the leukemic microenvironment. Therefore, strategies to enhance CART cell function to overcome these limitations are needed. Recent studies have shown that abnormal expression of the receptor tyrosine kinase (RTK) AXL is associated with poor prognosis in human cancers. AXL signaling is associated with tumor proliferation, survival, metastasis, and drug resistance. Inhibition of AXL RTK with TP-0903, a high affinity AXL inhibitor has been found to induce robust apoptosis of CLL B cells. Based on the significant modulation of T cell functions observed with BTK inhibitor, we examined the role of AXL RTK inhibition with TP-0903 on T cell function in CLL and other B cell malignancies. First, we investigated the effect of AXL inhibition on T cell phenotype in normal donors. When naïve T cells were stimulated with PMA/Ionomycin and cultured with low dose TP0903, cytokine production was favorably altered through the promotion of Th1 and reduction of Th2 cytokines. This was associated with a significant reduction of inhibitory receptors (Fig 1a). Western blot of T cell lysates suggests low dose TP-0903 results in inhibition of LCK. When effector T cells and regulatory T cells (Treg) were treated with TP-0903 for 3 days, there was a preferential reduction of Treg (Fig 1b). Next, we investigated the influence of TP-0903 on CART19 cell phenotype and functions. Here, we used 41BB costimulated, lentiviral-transduced CART cells. Similar to our findings on naïve T cells, TP-0903 treatment led to polarization of CART cells into a Th1 phenotype when T cells were stimulated with the CD19+ mantle cell lymphoma (MCL) cell line JeKo or with leukemic B cells isolated from CLL patients (Fig 1c). TP-0903 treatment also significantly downregulated inhibitory receptors on activated CART cells, including a reduction of canonical cytokines known to be associated with the development of cytokine release syndrome (CRS) (Fig 1c). The combination of CART19 cells and TP-0903 yielded a synergistic antitumor activity against JeKo in vitro, at low E:T ratios (Fig 1d). Western blot of T cell lysates revealed phosphorylation of LCK was remarkably reduced in the presence of TP-0903, suggesting a mechanism for the observed Th1 polarization. We compared the transcriptome of activated CART cells treated with TP-0903 and more than 100 genes were differentially expressed compared to non-treated cells. Among these genes, immune synapse related genes such as cell junction and cell migration related genes were significantly increased in activated CART cells treated with TP-0903. To investigate the effect of AXL RTK inhibition of CART cells with TP-0903 in vivo, we established MCL xenografts through the injection of 1.0x106 of JeKo into NSG mice. A week after the injection of JeKo, mice were treated with either vehicle alone, TP-0903 (20mg/kg/day) alone, 0.5x106 of CART19 alone, or TP-0903 (20mg/kg/day)+0.5x106 of CART19. Three weeks after the treatment, mice were rechallenged with 1.0x106 of JeKo. Mice treated with CART19 and TP-0903 rejected the JeKo tumor challenge while mice previously treated with CART19 alone redeveloped JeKo, suggesting that AXL inhibition enhanced CART cell persistence (Fig 1e). Finally, we validated our preclinical findings in a correlative analyses of Phase I clinical trial of TP-0903 for patients with solid tumors (NCT02729298). Blood T cells from 3 patients were isolated and analyzed before and a week after treatment with TP-0903. Similar to our findings, there was a significant reduction in Tregs, reduction of inhibitory receptors and polarization to a Th1 phenotype. These findings will be further investigated in a planned Phase I clinical trial of TP-0903 in relapsed/refractory CLL (NCT03572634). In summary, we demonstrated for the first time that AXL inhibitior is capable of polarizing T cells into a Th1 phenotype, downregulates inhibitory receptors, reduces CRS associated cytokines and synergizes with CART cells in B cell malignancies. These findings encourage further study of TP-0903 as an enhancer of T cell immunotherapies. Disclosures Mouritsen: Tolero Pharmaceuticals: Employment. Foulks:Tolero Pharmaceuticals: Employment. Warner:Tolero Pharmaceuticals: Employment. Parikh:Janssen: Research Funding; Abbvie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; MorphoSys: Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria. Ding:Merck: Research Funding. Kay:Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Research Funding; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees. Kenderian:Tolero Pharmaceuticals: Research Funding; Humanigen: Research Funding; Novartis: Patents & Royalties.

Abstract Introduction: Unprecedented clinical outcomes were reported after CD19 chimeric antigen receptor T cell (CART19) therapy and led to their FDA approval in diffuse large B cell lymphoma and in acute lymphoblastic leukemia. However, the complete response rate in chronic lymphocytic leukemia (CLL) after CART19 therapy is much lower, at approximately 20-30%, and the mechanism(s) for this relative lack of success is unclear. The dominant known mechanism(s) that prevent successful CART cell therapy in CLL have been limited to CART expansion and poor persistence. However, potential mechanisms are not limited to the CLL T-cell. Several immune defects have been identified in CLL that result from the complex bi-directional interaction between B-CLL cells and their microenvironment. In CLL the leukemic microenvironment is rich with extracellular vesicles (EVs) secreted by B-CLL cells. There is growing evidence that these vesicles play an important role in intracellular communication by the delivery of growth factors, genetic material and microenvironmentally relevant molecules. Therefore, we aimed to investigate the role and interactions of EVs in the diminished or absent CART response seen in some CLL patients. Methods: EVs were isolated from peripheral blood of 16 patients with untreated CLL at different Rai stages (8 patients had early and 8 had advanced stage disease) and risk profile by FISH (8 patients had low risk and 8 patients had high risk disease, based on the presence of 17p deletion). Cytometry was used to determine size, number of particles per µl, Annexin V and CD19 expression. These variables were correlated to the Rai stage and risk category of the disease. To investigate the impact of EVs on CART cell functions, CART19 cells were stimulated with either CLL EVs alone or in combination with the CD19 positive cell line JeKo1. After coincubation different effector functions were analysed. Results: Two patterns of EVs in CLL patients were identified; a single versus two distinct EV size populations (small [EVssmall]; 50-240nm, median=110nm) and large [EVslarge]; 180-560nm, median = 360nm Fig 1.A). In 25% of patients, EVs were CD19 positive (EVCD19+). CD19 positivity was detected only in patients with the EVslarge (Fig 1.B). The EVs concentration, CD19 expression (EVsCD19+ vs EVsCD19-), or the size (EVssmall vs EVslarge) did not correlate with disease stage (early vs advanced Rai stage) or risk profile of CLL (low vs high risk) although some variation could be seen (Fig 1.C). To investigate our hypothesis that EVs could modulate CART19 function, CART19 cell effector functions were examined in the presence of EVsCD19+, EVsCD19-, EVssmall, or EVslarge. EVs, 1.5x10e5 particles, alone were insufficient to stimulate CART19 cells. However when CART19 cells were stimulated with the CD19 positive cell line JeKo1, their effector functions were reduced only in the presence of EVsCD19+, 50,000 particles, 2.5 x 10e3/ µl, but not EVsCD19- at the same concentration. This included a significant reduction in CART specific killing (Fig 1.D) and a reduction in cytokine production. The impairment of CART cell functions was independent of the size of EVs, i.e. there was no impairment of CART functions with large or small size EVCD19- in co-culture. Summary: We identify CD19 positive large size EVs from patients with CLL and demonstrate that these EVs play a role in the leukemic microenvironment by reducing CART cell activity. Studies are ongoing to define the mechanism(s). Disclosures Parikh: Janssen: Research Funding; AstraZeneca: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria; MorphoSys: Research Funding; Abbvie: Honoraria, Research Funding. Kay:Cytomx Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Research Funding; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees. Kenderian:Tolero Pharmaceuticals: Research Funding; Humanigen: Research Funding; Novartis: Patents & Royalties.

Abstract Introduction: The impact of genomic alterations, such as mutations in ASXL1, on the risk of disease progression and leukemic transformation in patients with myelofibrosis (MF) is well established. Further, emerging data suggests that the number and type of mutations may impact response to therapies such as ruxolitinib or imetelstat. Allogeneic hematopoietic stem cell transplant (allo-HSCT) remains the only potentially curative treatment for MF patients. However, the impact of somatic mutations on overall survival (OS) and relapse-free survival (RFS) is poorly understood. Using next-generation sequencing of pre-transplant blood and bone marrow samples from a well clinically-annotated cohort of MF patients who underwent allo-HSCT, we sought to determine the impact of mutational burden on outcomes. Methods: A multicenter retrospective analysis of a cohort of 84 patients was carried out. This included 52 patients treated on the MPD-RC 101 prospective study (NCT00572897), 18 patients treated at Prince Margaret Hospital, and 14 patients treated at Memorial Sloan Kettering Cancer Center. Patient and transplant characteristics are displayed in Table 1. DNA was extracted from pre-transplant bone marrow aspirate samples or peripheral blood samples. High-throughput sequencing of a panel of genes was performed. Average coverage of 829x (standard deviation of ±130) was obtained. Mutect was utilized to call single point variants (comparing our samples to a pool of normal samples) and PINDEL was used to call short insertions and deletions. We excluded all mutations present in at least one database of known non-somatic variants (DBSNP and 1000 genomes) and absent from COSMIC. Univariate Cox regression and Kaplan-Meier graphics were used to investigate the association of patient, transplant, and disease characteristics with OS and RFS. Results: JAK2V617F was the most frequent mutation detected in 41(48.8%) patients (Table 2). Eighteen patients (21.4%) had triple negative disease (negative for JAK2, MPL, and CALR mutations). Univariate analysis included the following: patient characteristics (age, gender), transplant characteristics (related vs. unrelated donor, matched vs. mismatched donor and myeloablative vs. reduced intensity conditioning) and disease characteristics (DIPSS and presence of mutations). Decreased OS was associated with unrelated donor status (HR 2.09, 95% CI: 1.03-4.23, p=0.04), reduced intensity conditioning (HR 4.21, 95% CI: 1.01-17.59, p=0.049), triple negative disease (HR 2.09, 95% CI: 1.02-4.30, p=0.04), and presence of U2AF1 (HR 2.53, 95% CI: 1.10-5.81, p=0.03) or SUZ12 mutations (HR 3.92, 95% CI: 1.19-12.21, p=0.02). Decreased RFS was associated with unrelated donor status (HR 2.27, 95% CI: 1.16-4.45, p=0.02), and the presence of SUZ12 mutation (HR 6.97, 95% CI: 2.37-20.49, p<0.001). A descriptive decrease in RFS in patients with U2AF1 (HR 2.15, 95% CI: 0.94-4.88, p=0.07) was observed but did not reach statistical significance. Importantly, mutations previously reported to be associated with reduced OS and RFS in the non-transplant setting, such as ASXL1, EZH2, IDH1/2, and SRSF2, were not associated with poorer outcomes in this analysis in transplanted patients. In an exploratory multivariate analysis including donor type (related vs. unrelated) and presence of U2AF1 and SUZ12 mutations, there was a significantly reduced OS and RFS in patients who harbor these mutations regardless of donor type (OS: HR 5.30, 95% CI: 2.08-13.47, p<0.001; RFS: HR 5.49, 95% CI: 2.27-13.30, p<0.001). In patients without the above mutations, having an unrelated donor was associated with worse OS (HR 2.55, 95% CI: 1.09-5.96, p=0.03) and RFS (HR 2.61, 95% CI: 1.17-5.83, p=0.02, Figure 1). Conclusions: Our analysis demonstrates that mutations previously associated with poor prognosis in MF, such as ASXL1, do not appear to confer a worsened prognosis in patients undergoing allo-HSCT, suggesting transplant may be able to overcome the impact of these mutations. However, mutations in SUZ12 and U2AF1 are associated with reduced OS in univariate and multivariate analysis (together with donor type). Further studies with larger cohorts of patients are indicated to validate these findings, and to elucidate the impact of these mutations on disease biology. Disclosures Rampal: Incye and CTI: Consultancy. Mascarenhas:Janssen: Research Funding; CTi Biopharma: Research Funding; Promedior: Research Funding; Merk: Research Funding; Incyte: Research Funding. Mesa:Galena: Consultancy; Gilead: Research Funding; Promedior: Research Funding; Incyte: Research Funding; CTI Biopharma: Research Funding; Celgene: Research Funding; Ariad: Consultancy; Novartis: Consultancy. Gupta:Novartis: Consultancy, Honoraria, Research Funding; Incyte Corporation: Consultancy, Research Funding.

Abstract Background: Myeloproliferative neoplasms (MPN) including polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF) are clonal hemopathies characterized by burdensome symptom profiles and impaired quality of life. Few studies have evaluated patient-reported outcomes during treatment with non-experimental pharmacological regimens. Aims: The Myeloproliferative Neoplasm Quality of Life (MPN-QOL) Study Group aims to objectively quantify MPN symptom severity, frequency and quality of life at baseline and throughout treatment with non-experimental therapies utilizing the Myeloproliferative Neoplasm Symptom Assessment Form - Total Symptom Score (MPN-SAF TSS; JCO 2012). In this abstract, we provide updated results for the prospective international cohort trial currently in active enrollment: the MPN Experimental Assessment of Symptoms by Utilizing Repetitive Evaluation (MEASURE) trial. Methods: This study aims to recruit 180 international ET, PV, and MF (including primary MF and post-ET or post-PV MF) patients receiving non-experimental medical therapy and/or phlebotomy. Patients complete the MPN-SAF for seven consecutive days at enrollment and repeat the survey for an additional seven consecutive days between 90 days and six months. Patients also complete the European Organisation for Research and Treatment of Cancer (EORTC) and M.D. Anderson Symptom Inventory (MDASI) instruments at enrollment and on the first day of the second assessment. At visits, physicians acquired demographic, laboratory, physical examination, and radiographic data. Descriptive statistics were used to summarize data. Results: Clinical Data The MEASURE trial opened for enrollment in 2012 and remains in recruitment phase with 15 participating international sites. To date, 39 patients have been enrolled and 25 have completed both study visits. Participants include ET (28%), PV (24%), and MF (48%; 50% primary MF, 8% post-ET, 42% post-PV) patients. The majority of patients are male (64%) and of expected age (mean 69.3, range 39-89) for the disorders. Seventeen percent had prior thrombosis, 9% required red blood cell transfusion, and none reported prior splenectomy or hemorrhage. Mean hematologic measures included hemoglobin 13.2 g/dL, WBC count 11.4 x109/L, ANC 8.5 x109/L, and platelets 514 x109/L. Therapies received prior to enrollment included aspirin (n=16), hydroxyurea (n=11), phlebotomy (n=8), warfarin/clopidogrel/anticoagulation (n=8), erythropoietin (n=2), and interferon (n=1). The most common current MPN therapies were hydroxyurea (n=9), aspirin (n=9), interferon (n=4), and phlebotomy (n=2). Symptom Assessment In comparing MPN-SAF TSS mean symptom scores, all symptoms except bony pain improved between the first and second visits, including fatigue, early satiety, abdominal discomfort, inactivity, concentration, night sweats, itching, fever, weight loss, and overall quality of life (Figure1). Total MPN-SAF TSS scores improved from a mean of 32.3 to 25.9. On the EORTC, mean scores for physical, role, emotional, and social functioning improved from the first to the second visit (Figure 2). Cognitive functioning showed a slight decline. Global health status measure improved from 60.2 to 72.9. On the MDASI, symptom severity scores decreased from 3.6 to 2.8 from the first to second visit (Figure 3). Symptom distress measure decreased from 4.1 to 3.0. Discussion: Interim results from the MEASURE trial demonstrate that standard, non-experimental treatment regimens offer improvement in quality of life-related symptoms on multiple patient-reported survey instruments including the MPN-SAF TSS, EORTC QLQ-C30, and MDASI. Updated data including symptom correlations and mutational analysis to be presented at the 2016 ASH conference. Disclosures Ross: Novartis Pharmaceuticals: Honoraria, Research Funding; BMS: Honoraria. Radia:Novartis: Honoraria; Pfizer: Honoraria. McMullin:Novartis: Honoraria, Speakers Bureau. Cargo:Novartis: Honoraria; Celgene: Honoraria, Research Funding. Sekhar:Novartis: Research Funding. Mesa:Gilead: Research Funding; CTI Biopharma: Research Funding; Galena: Consultancy; Ariad: Consultancy; Incyte: Research Funding; Novartis: Consultancy; Celgene: Research Funding; Promedior: Research Funding.

Abstract Abstract 664 Background: Survivors of childhood acute lymphoblastic leukemia (ALL) who received prophylactic cranial radiation therapy (CRT) are at increased risk for deficits in neurocognitive skills, including attention, working memory and processing speed. As survivors age, global brain injury from CRT may reduce cognitive reserve, placing them at risk for early onset dementia or long-term memory deficits. The prevalence of dementia and memory abnormalities in adult survivors of childhood ALL has not previously been established. Methods: Analyses were conducted on 265 of 445 (60%) eligible survivors of childhood ALL (median age 36 years, range 26–54 years; 52% female) treated with 18Gy (n=127) or 24Gy (n=138) CRT with a median time from CRT of 30 years (range 15–46 years). Participants completed the Wechsler Memory Scale IV, including the Brief Cognitive Status Exam (BSCE), and the Wechsler Abbreviated Scale of Intelligence (WASI). Age-adjusted standard scores were calculated and the BSCE was also adjusted for education level. Prevalence of memory impairment (<1 SD below age-expected mean), stratified by RT dose exposure, is reported and logistic regression used to identify risk factors for impairment. A subset of survivors (n=85) completed brain magnetic resonance imaging (MRI), including assessment of hippocampal volume, cortical thickness, white matter volume, diffusion tensor imaging, and functional MRI (fMRI) during a cued-recall memory task. Results: Survivors who received 24 Gy CRT had increased impairment on global measures of both short-term recall (33%; p<0.001) and long-term recall (30%; p<0.001), while no increase in impairment was seen after 18Gy. Impaired short-term recall was associated with smaller right (p=0.02) and left (p<0.01) temporal lobe volumes, while impaired long-term recall was associated with thinner parietal and frontal cortices. On subtests evaluating narrative memory (i.e. story recall) and design memory, increasing RT dose (24 vs. 18Gy) was associated with an increased prevalence of long-term memory impairment (narrative: 28% vs. 12%, p=0.001; designs: 13% vs. 3.2%, p=0.003). However, no CRT dose response was identified for short term narrative and design memory. Survivors with impaired long-term memory for designs demonstrated a compensatory increase in left hippocampal fMRI activation (p=0.005), and the effect was greater in the higher dose group (p = 0.04). The mean score for long-term narrative memory among survivors who received 24Gy was equivalent to the mean score of a 70–74 year old adult population. Neither young age (0–4 years) at CRT (Odds Ratio [OR] 1.4, 95% confidence interval [CI] 0.8–2.7), time from CRT (OR 1.0, 95% CI 0.9–1.1) nor intrathecal methotrexate exposure (OR 3.9, 95% CI 0.4–36.1) were significantly associated with long-term memory deficits. Reduced cognitive status (by BSCE) was identified after 18Gy (9%, p=0.11) and 24Gy (18%, p<0.001), suggesting a CRT dose-response effect. On diffusion tensor imaging, increased radial diffusivity in the frontal, parietal and temporal regions, an inverse measure of white matter integrity, was associated with reduced BSCE. Current employment rates were equivalent (63%) in both CRT dose groups, suggesting no difference in functional status. Conclusions: Aging adult survivors of ALL who received 24Gy CRT have reduced cognitive status and significant impairment in short-term and long-term memory. There appears to be a dose response effect selective for long-term narrative and design memory, but not for short term narrative and design memory. These patterns are consistent with early onset of age-related (long-term) memory loss, and early stage dementia, yet at a median age of only 36 years. After 24Gy, survivors have the narrative memory equivalent to a 70 year-old in the general population. Survivors with memory impairment demonstrated reduced integrity on structural and functional neuroimaging in anatomical regions established as essential for memory formation and long-term recall. However, these memory impairments do not seem to affect functional status (employment rates) suggesting that, rather than frank dementia, deficits in middle adulthood are consistent with mild cognitive impairment (MCI). Longitudinal evaluation of this population is needed as MCI often progresses into early onset dementia with age. Disclosures: No relevant conflicts of interest to declare.

INTRODUCTION: Prometheus IBD sgi Diagnostic (SGI) is an Inflammatory Bowel Disease (IBD) advanced diagnostic test developed by Prometheus Laboratories. It employs a diagnostic algorithm combining serologic, genetic, and inflammatory markers to help with clinical decision making in determining the accuracy of a diagnosis of IBD in patients suspected to have the disease. Moreover, among those it identifies as having IBD, it also seeks to assist in distinguishing those with Crohn's vs. those with ulcerative colitis (UC). In this observational clinical decision making study, we sought to examine the real world application of the SGI at a single tertiary care IBD practice especially in correctly identifying those with Crohn's vs. those with UC. METHODS: We included all adult IBD patients seen at a single tertiary IBD center practice from 2014 to 2017 that had baseline SGI done and during care at the practice, had a diagnosis of IBD (Crohn's or UC) established. We calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and area under the curve based on results of SGI at baseline visit and the eventual established diagnosis of UC or CD. RESULTS: Of a total of 275 patients, there were 96 (34.9%) male patients and 179 (65.1%) female patients. The median age of these patients was 45.8. There were a total of 201 patients with biopsy proven CD. Of these, 104 were identified as having CD based on the baseline SGI and 97 who were identified as not having CD. Based on these data, the sensitivity of the SGI for CD at the practice was 52%, specificity was 88%, PPV was 92%, NPV was 40.1%, diagnostic accuracy was 61.5%, and Area under ROC was 70%. There were 66 patients with biopsy proven UC. Of these, 44 were identified as having UC based on the baseline SGI and 22 were identified as not having UC. Based on these data, the sensitivity of the SGI for UC at the practice was 67%, specificity was 85%, PPV was 58%, NPV was 89%, accuracy was 80%, and Area under ROC was 76%. CONCLUSION: Based on the results of this study, we conclude that the SGI is not a robust initial test in identifying those with Crohn's or those with UC. However, in a cohort of IBD patients seen at a tertiary care IBD practice, it is reasonably specific and accurate when it comes to correctly confirming Crohn's and even more so UC in patients with a caveat that the results should be interpreted in the proper clinical context and with the backing of other clinical indicators.

INTRODUCTION: Crohn's Disease (CD) is a chronic inflammatory condition, primarily of the gastrointestinal tract with an increasing incidence and prevalence worldwide. In clinical practice, gastroenterologists are often faced with challenges in evaluating disease activity, severity, and prognosis to guide appropriate management of CD. We studied the association between serum albumin level and the rate of active clinical disease in CD patients seen at a tertiary care Inflammatory Bowel Disease (IBD) referral center. METHODS: We designed a retrospective cohort study using adult patients (>18 years) with CD followed for at least one year at University of Alabama at Birmingham (UAB) IBD center by a single trained IBD specialist between 2014-2018. Serum albumin levels were divided into: low mean serum albumin (≤3.2 mg/dL) vs. appropriate mean serum albumin (>3.2 mg/dL). Clinical disease activity was measured using the Harvey-Bradshaw index (HBI). Active disease was defined as HBI score of 8 or higher. Poisson Regression Models (GPR) for Rate Data were used to estimate partially adjusted and fully adjusted incidence rate ratios (IRR) of active clinical disease among CD patients. We also examined IRRs for serum albumin level as a continuous variable. RESULTS: In this single IBD practice at UAB, 269 patients with CD had albumin drawn at initial visit and serially at each subsequent visit. Poisson regression model adjusted for age, gender, race, duration of disease, steroid use, smoking and Crohns location demonstrated that CD patients with a low mean serum albumin during clinical observation were approximately 1.5 times more likely to have active clinical disease during observation (IRR 1.49, 95% CI 1.04-2.15, P = 0.032) compared to those with a serum albumin level of >3.2 mg/dL. The adjusted model with serum albumin as a continuous variable demonstrated that with every unit (0.1 mg/dL) reduction in mean serum albumin, there was 30% higher likelihood of active Crohns in clinic (IRR 1.30, 95% CI 1.02-1.66, P = 0.037). CONCLUSION: Lower mean serum albumin during clinical observation is associated with a higher likelihood of active clinical disease among CD patients. Whether interventions designed to correct or increase serum albumin stores/levels in these patients would be beneficial remains to be examined.