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Castleman disease (CD) describes a group of rare, potentially fatal lymphoproliferative disorders. To determine factors associated with mortality in CD, we analysed data from deceased patients in the ACCELERATE registry and compared them with matched controls. We analysed demographic, treatment and laboratory data from all deceased CD patients, matched controls and a subgroup of idiopathic multicentric Castleman disease (iMCD) patients. Of the 140 patients in ACCELERATE with a confirmed CD diagnosis, 10 had died. There were 72 patients with confirmed iMCD; six were deceased. The deceased CD cohort had more hospitalisations per year, higher overall hospitalisations and more days hospitalised per month, and received more treatment regimens per year than the matched-control group. Analysis of laboratory values showed a significantly decreased absolute lymphocyte count at months 3 and 6 in the deceased cohort compared with controls. Among iMCD patients, there was a higher proportion of iMCD-TAFRO (thrombocytopenia, anasarca, fever, reticulin myelofibrosis, renal dysfunction and organomegaly) cases in the deceased group. The deceased iMCD group had significantly lower immunoglobulin M, international normalised ratio and platelet count. These data demonstrate that there may be differences between patients who have fatal and non-fatal outcomes, and provide preliminary suggestions for parameters to evaluate further.

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Therapy-related acute myeloid leukemia and myelodysplastic syndromes (t-AML/t-MDS) are secondary hematologic malignancies associated with poor prognosis, warranting insights into their predisposing conditions and cells of origin. We identified patients with myeloma who developed t-AML/t-MDS and analyzed their stem and progenitor cells collected years before the onset of secondary disease. We demonstrate that aberrant stem cells with high CD123 expression can be detected long before the onset of overt leukemia. Rigorous sorting, followed by targeted sequencing, resulted in ultradeep functional depth of sequencing and revealed preexisting mutant hematopoietic stem cell (HSC) clones, mainly harboring TP53 mutations, that became the dominant population at the time of leukemic presentation. Taken together, these data show that HSCs can act as reservoirs for leukemia-initiating cells many years before the onset of myeloid leukemia.

Background The tumor microenvironment (TME) is increasingly appreciated as an important determinant of cancer outcome, including in multiple myeloma (MM). However, most myeloma microenvironment studies have been based on bone marrow (BM) aspirates, which often do not fully reflect the cellular content of BM tissue itself. To address this limitation in myeloma research, we systematically characterized the whole bone marrow (WBM) microenvironment during premalignant, baseline, on treatment, and post-treatment phases. Methods and findings Between 2004 and 2019, 998 BM samples were taken from 436 patients with newly diagnosed MM (NDMM) at the University of Arkansas for Medical Sciences in Little Rock, Arkansas, United States of America. These patients were 61% male and 39% female, 89% White, 8% Black, and 3% other/refused, with a mean age of 58 years. Using WBM and matched cluster of differentiation (CD)138-selected tumor gene expression to control for tumor burden, we identified a subgroup of patients with an adverse TME associated with 17 fewer months of progression-free survival (PFS) (95% confidence interval [CI] 5–29, 49–69 versus 70–82 months, χ2 p = 0.001) and 15 fewer months of overall survival (OS; 95% CI –1 to 31, 92–120 versus 113–129 months, χ2 p = 0.036). Using immunohistochemistry-validated computational tools that identify distinct cell types from bulk gene expression, we showed that the adverse outcome was correlated with elevated CD8+ T cell and reduced granulocytic cell proportions. This microenvironment develops during the progression of premalignant to malignant disease and becomes less prevalent after therapy, in which it is associated with improved outcomes. In patients with quantified International Staging System (ISS) stage and 70-gene Prognostic Risk Score (GEP-70) scores, taking the microenvironment into consideration would have identified an additional 40 out of 290 patients (14%, premutation p = 0.001) with significantly worse outcomes (PFS, 95% CI 6–36, 49–73 versus 74–90 months) who were not identified by existing clinical (ISS stage III) and tumor (GEP-70) criteria as high risk. The main limitations of this study are that it relies on computationally identified cell types and that patients were treated with thalidomide rather than current therapies. Conclusions In this study, we observe that granulocyte signatures in the MM TME contribute to a more accurate prognosis. This implies that future researchers and clinicians treating patients should quantify TME components, in particular monocytes and granulocytes, which are often ignored in microenvironment studies., Author summary Why was this study done? The cells around a tumor, also known as the tumor microenvironment (TME), can help a tumor grow by suppressing the immune system or fight a tumor by mounting an immune response. Most studies of multiple myeloma (MM) have focused on the tumor itself, rather than the bone marrow (BM) TME in which the tumor is growing. We hypothesized that the MM TME held clues that could help us better treat patients. What did the researchers do and find? We used a gene-expression–based computational technique to determine which cell types were present in patient BM. Patients with BM lacking a family of innate immune cells called granulocytes presented with worse outcomes compared to other patients. As MM progresses from a predisease to a cancerous state, the percentage of granulocytes decreases; the patients with the fewest granulocytes had more serious diseases. What do these findings mean? If granulocytes help myeloma patients respond to therapy, then addressing the decline in granulocytes may improve MM treatment. Patients with MM and few granulocytes in their BM should be watched for worse outcomes.

Multiple myeloma (MM) patients frequently attain a bone marrow (BM) minimal residual disease (MRD) negativity status in response to treatment. We identified 568 patients who achieved BM MRD negativity following autologous stem cell transplantation (ASCT) and maintenance combination therapy with an immunomodulatory agent and a proteasome inhibitor. BM MRD was evaluated by next-generation flow cytometry (sensitivity of 10−5 cells) at 3- to 6-month intervals. With a median follow-up of 9.9 years from diagnosis (range, 0.4-30.9), 61% of patients maintained MRD negativity, whereas 39% experienced MRD conversion at a median of 6.3 years (range, 1.4-25). The highest risk of MRD conversion occurred within the first 5 years after treatment and was observed more often in patients with abnormal metaphase cytogenetic abnormalities (95% vs 84%; P = .001). MRD conversion was associated with a high risk of relapse and preceded it by a median of 1.0 years (range, 0-4.9). However, 27% of MRD conversion-positive patients had not yet experienced a clinical relapse, with a median follow-up of 9.3 years (range, 2.2-21.2). Landmark analyses using time from ASCT revealed patients with MRD conversion during the first 3 years had an inferior overall and progression-free survival compared with patients with sustained MRD negativity. MRD conversion correctly predicted relapse in 70%, demonstrating the utility of serial BM MRD assessment to complement standard laboratory and imaging to make informed salvage therapy decisions.

Introduction The iliac crest is the usual sampling site for minimal residual disease (MRD) monitoring in Multiple Myeloma (MM). However, the disease distribution in the bone marrow (BM) is often heterogeneous. Functional imaging can be used to complement MRD detection at a single site, thereby accounting for asymmetrically distributed disease. Diffusion weighted MRI with background suppression (DWIBS) is a novel functional imaging method that can detect disease in a higher proportion of newly diagnosed MM (NDMM) patients than 18F-fluorodeoxyglucose positron emission tomography (PET), as it is independent of the tumor metabolism. Yet, its performance for monitoring of residual disease has not been described. The aims of this study were 1) to compare DWIBS to PET for the detection of residual disease in patients achieving complete remission (CR), and 2) to test whether DWIBS and PET could complement MRD flow cytometry with a sensitivity of 1x10-5. To address these aims, we investigated 168 NDMM and 33 relapsed patients for whom DWIBS, PET, and MRD were available at the onset of CR during first-line and salvage therapy, respectively. Methods All patients signed written consent in accordance with the Declaration of Helsinki. Residual focal lesions (FLs) were defined as well delineated focal intensities above the surrounding BM background. For DWIBS FLs were considered if restriction could be confirmed on ADC maps. 8-color MRD flow cytometry with a limit of detection of 1x10-5 was available for 83 NDMM and all 33 salvage therapy patients. The Kaplan-Meier method was used for survival analyses. PFS time was measured from onset of CR to relapse or death from any cause or censored at the date of last contact. Paired-end whole exome sequencing of CD138-enriched MM cells was performed on an Illumina HiSeq 2500. Mutations were called from BWA aligned sequencing reads using MuTect. Subclonal reconstruction was done using SciClone. Results Compared to PET, DWIBS detected more CR patients with residual FLs (21% vs. 6%), and the concordance between PET and DWIBS was low. Only 6 of the DWIBS-positive patients also presented with FLs in PET. Yet, 5 patients had PET+/DWIBS- FLs, suggesting that the two techniques are complementary. Both, DWIBS+ and PET+ FLs negatively impacted PFS (p For 83 patients MRD data were available. Combining MRD and imaging, residual disease was detectable in 53 patients (64%). The best outcome was seen for 30 double negative (MRD-/Imaging-) patients (3 events with a median follow-up of 3.6 years), the worst outcome was seen for 10 double positive (MRD+/Imaging+) patients (median PFS: 2.1 years). Only 4 of 86 patients were MRD-/Imaging+, indicating that residual FLs are rare in MRD-negative NDMM patients at a sensitivity of 1x10-5. A heterogeneous disease distribution is a common feature of late-stage patients. To test if this increased heterogeneity confounded MRD, we investigated a set of 33 heavily pretreated patients who achieved CR during salvage therapy. Combining MRD and imaging data, we detected residual disease in 25 patients (76%). Of note, the proportion of patients, who were MRD-negative but had residual FLs on functional imaging was significantly higher compared to NDMM (8/16 vs 4/34 patients, p=0.01). At the same time, 10 patients (30%) were MRD+ but Imaging-, supporting the idea that a combined MRD/Imaging approach can improve detection of residual disease and should be used in late-stage patients. To obtain insights in the underlying biology, we performed longitudinal multi-region sequencing of a subset of these CR patients. Our findings support the concept of persistence and progression of multiple spatially separated clones in the BM irrespective of being in an MRD-negative CR. Thereby, focal residual disease could be shown to contribute to relapse. Conclusion DWIBS is a promising tool for detection of residual disease and complements PET. The combination of MRD diagnostics and functional imaging improves prediction of outcome, with double-negativity and double positivity defining groups with excellent and dismal PFS, respectively. Prospective trials using this information to tailor therapy are warranted. From a biological perspective, this study highlights the confounding effects of spatial heterogeneity and limited dissemination of clones within the BM on MRD diagnostics. This may especially be true for patients achieving deep responses during salvage therapies. Disclosures Roy Choudhury: University of Arkansas for Medical Sciences: Employment, Research Funding. Epstein:University of Arkansas for Medical Sciences: Employment. Barlogie:International Workshop on Waldenström's Macroglobulinemia: Other: travel stipend; Millenium: Consultancy, Research Funding; Multiple Myeloma Research Foundation: Other: travel stipend; ComtecMed- World Congress on Controversies in Hematology: Other: travel stipend; Myeloma Health, LLC: Patents & Royalties: : Co-inventor of patents and patent applications related to use of GEP in cancer medicine licensed to Myeloma Health, LLC; European School of Haematology- International Conference on Multiple Myeloma: Other: travel stipend; Celgene: Consultancy, Research Funding; Dana Farber Cancer Institute: Other: travel stipend. Davies:Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Research Funding.

Introduction: Flow cytometric immunophenotyping is considered an indispensable tool for the diagnosis, classification, and monitoring of plasma cell disorders. Herein, we seek to study the clinical significance of expression of phenotype markers in monoclonal gammopathy of unknown significance (MGUS). Methods: We identified a cohort of patients with a diagnosis of MGUS from the institutional myeloma database. Bone marrow (BM) aspirate assessment was performed using 8-color immunophenotypic next-generation flow cytometric (NGF) analysis with a minimum sensitivity of 10 -5 cells at the time of diagnosis or first visit to our institution. BM aspirate samples were immunophenotyped on a FACSCanto II flow cytometer using antibodies (BD) to delineate normal and abnormal plasma cells [CD138 (V-500), CD38 (FITC), CD19 (PE-Cy7), CD45 (V-450), CD27 (PercpCy5.5), CD81 (APC-H-7), CD56 (APC) and CD20 (PE)]. The sensitivity or the Limit of Detection (LOD) for this assay was validated to 20 cells in 2 ×10 6 events (0.001%), and the reproducibility or Lower Limit of Quantitation (LLOQ) is 50 cells in 2 ×10 6 events. Clinical and laboratory variables were also collected. Based on previously published data, expression (CD19, CD45, CD81), and lack of expression (CD56, CD27, CD20) of the above-mentioned surface antigens were analyzed. Additional variables such as IgA isotype, size of M-protein (≥15 g/L), and abnormal free light chain ratio(abnFLR) (defined as 10) were included in regression fitting models. Results: A total of 157 patients with MGUS were included in this analysis. The median age at diagnosis was 60 years (range 24- 84), 84 (53 %) patients were female and 25 (16%) were African American. Overall, IgG Kappa (75/148, 50%) was the most common isotype. Fluorescent-in-situ hybridization (FISH) data were available in 35 patients with t (4:14) and t (14;16) seen in 3 patients each. At a median follow-up of 18.15 years (quantiles 11.35, 33.62), 28 patients experienced disease progression (25 to MM, 2 to Waldenstrom macroglobulinemia, and 1 Smoldering myeloma). The median progression-free survival of this cohort was 17.3 years. Among these, occurrences of the bone lesion (8/28; 28.6%) were the most common pattern of disease progression to MM. This analysis showed lower odds of progression with the expression of CD27 (OR-0.39, 95% CI 0.15-0.99) (figure 1A). Disease progression was more common in patients with an abnormal plasma cell clone size ≥ of 3.1% at diagnosis (60% vs. 12.5%, p=0.0005). An abnormal plasma cell clone of ≥3.1% at diagnosis, was associated with increased odds of progression (OR-10.79, 95% CI 4.02-28.98) and a shorter PFS (12.5 years versus NR, p=0.01) (figure 1B). Serum M-spike ≥1.5 g/dL (OR-3.54;95% 1.30-9.62) and abnFLR (OR-2.30, 95% CI 1.00-5.32) were also associated with a higher odds of progression. However, in this population, the presence of IgA isotype did not increase the odds of MGUS progression. In a stepwise regression model, serum M-spike≥1.5 g/dL, abnFLR, and the lack of expression of CD27 were associated with the risk of disease progression. Conclusion: In addition to previously published risk factors, our cohort shows that the expression of CD27 antigen by eight-color flow cytometry confers a lower risk of disease progression of MGUS. This is consistent with our previous report that CD27 is progressively down-regulated in the transition from normal plasma cells (NPC) to MGUS to MM (Zhan et al, Blood 2006). Furthermore, we show that size of the myeloma clone (≥ 3.1% ) is a possible surrogate marker for disease progression in MGUS. Figure 1: 1A shows forest plot of odds ratios for flow cytometry markers, IgA isotype, size of M protein, abnFLR and plasma cell clone size. 1B shows the Kaplan Meier estimates of PFS for patients stratifies by plasma cell clone size. Figure 1 Figure 1. Disclosures Mohan: Medical College of Wisconsin: Current Employment. Atrash: GSK: Research Funding; AMGEN: Research Funding; Jansen: Research Funding, Speakers Bureau.

Castleman disease (CD) describes a group of heterogeneous lymphoproliferative disorders with characteristic histopathology that are classified based on the number of enlarged lymph node (LN) stations, etiological drivers, and clinical phenotype. CD histopathology includes a broad spectrum from plasmacytic to hyaline/hyper vascular with a mixed pattern in between. Unicentric CD (UCD) involves a single enlarged LN station and mild symptoms, whereas multicentric CD (MCD) involves multiple stations of enlarged LNs and more severe symptoms. MCD is subclassifed into Human Herpesvirus-8 associated MCD, POEMS-associated MCD, and idiopathic MCD (iMCD). iMCD cases are further subdivided into thrombocytopenia, anasarca, fever/elevated C-reactive protein (CRP), renal dysfunction, organomegaly (TAFRO) or iMCD-not otherwise specified (NOS), who often have thrombocytosis and hypergammaglobulinemia. Recently, it has been reported that some iMCD patients can have more oligocentric lymphadenopathy (above or below the diaphragm) whereas others have generalized lymphadenopathy (above and below the diaphragm). Given the heterogeneity across CD, we leveraged data from a longitudinal natural history study of CD to characterize the spectrum of CD. Specifically, we set out to determine if patients with multicentric lymphadenopathy localized to above or below the diaphragm (oligocentric CD, OCD) appeared to be more similar to UCD or iMCD with more generalized lymphadenopathy. In total, 130 patients enrolled in an international CD registry were confirmed to have CD by a panel of experts. Patients were assigned UCD, OCD, or iMCD per the following: UCD, 1 station of enlarged LNs (N=32); OCD, ≥2 stations of enlarged LNs, either above or below the diaphragm (N=29); iMCD, ≥2 stations of enlarged LNs, both above and below the diaphragm (N=69). Clinical data is provided closest to date of diagnosis +/-90 days. Sustained response is defined as ≥50% symptom improvement sustained without the addition of subsequent drug treatments. When appropriate, statistical testing was performed by Chi-square, Fisher's exact, or two-tailed T test. Among the 69 iMCD patients, 42 (61%) were classified as TAFRO and 27 (39%) were NOS. In contrast, only 1 of 29 OCD patients (3%) was TAFRO and 28 (97%) were NOS. No UCD patients were TAFRO. Breakdown of histopathological subtype can be found in Table 1. There was a mean (SD) of 8.4 (3.7) enlarged LNs in iMCD at diagnosis, compared with 2.8 (1.4) in OCD and 1 (0) in UCD. While enlarged LNs in the abdomen/pelvis region occurred in 56% of UCD, only 19% of OCD patients demonstrated lymphadenopathy in this region. Clinically, OCD patients demonstrated symptoms and laboratory abnormalities more comparable to UCD than iMCD (Table 2). In fact, there was no difference in symptoms between UCD and OCD groups, while there were significantly more symptoms in iMCD than OCD. iMCD had significantly worse anemia, albumin, creatinine, CRP, and other markers of inflammation than OCD, whereas OCD patients had significantly increased CRP (p=0.03) and alkaline phosphatase (p=0.03) compared to UCD. IgM was greater in OCD than both UCD (p=0.02) and iMCD (p=0.01) (Table 2). The number of patients receiving drug treatments differed by subtype: 7 UCD (22%), 18 OCD (62%), and 67 iMCD (97%). Fifty-five patients (UCD: 1, OCD: 7, iMCD: 47) received anti-IL-6 therapy (+/- steroids), including the only FDA-approved drug, siltuximab. Sustained response to anti-IL-6 (+/- steroids) was observed in 23/47 (49%) iMCD, 3/7 (43%) OCD, and 0/1 UCD. Within iMCD clinical subgroups, response was observed in 12/27 (44%) iMCD-TAFRO and 11/20 (55%) iMCD-NOS as well as across the histopathogical subtypes, suggesting that anti-IL-6 therapy can be effective across the spectrum. Overall, this study highlights the heterogeneity of CD. Importantly, it uncovers a group of CD patients that meet diagnostic criteria for iMCD but their lymphadenopathy is confined to above or below the diaphragm and they appear to behave more similarly to UCD. Given that 1/3 of OCD patients were managed without drug treatment, further work is needed to determine the relative benefits of UCD-like surgical treatment versus iMCD-like drug-based therapy for OCD. The clinical subtype of TAFRO, which was present in more than half of the iMCD patients, was observed in only one OCD case and no UCD cases. Further work is needed to determine optimal treatments across these subgroups. Figure 1 Figure 1. Disclosures Bagg: Scopio Labs: Research Funding. Lim: EUSA Pharma: Honoraria. Srkalovic: Takeda: Speakers Bureau; Janssen Pharmaceuticals: Speakers Bureau; EUSA Pharma: Speakers Bureau; Foundation Medicine: Speakers Bureau. Uldrick: Merck: Other: Receives study drug; Roche: Research Funding; Regeneron: Current Employment; Celgene: Research Funding. Fajgenbaum: Pfizer: Other: Study drug for clinical trial of sirolimus; N/A: Other: Holds pending provisional patents for 'Methods of treating idiopathic multicentric Castleman disease with JAK1/2 inhibition' and 'Discovery and validation of a novel subgroup and therapeutic target in idiopathic multicentric Castleman disease'; EUSA Pharma: Research Funding.

Introduction- Chromosome 1 abnormalities in multiple myeloma (MM) are increasingly recognized as high risk defined features. While there is robust data on 1q21 gain and amplification (amp), the clinical characteristics and outcome of patients with del 1p is less defined. Novel agents are incorporated into a backbone of multi-agent chemotherapy and tandem autologous stem cell transplantation (ASCT) in successive Total Therapy (TT) protocols for MM patients. We hereby report the prognostic value of del 1p by FISH at enrollment in subjects treated on TT protocols. Methods: (FISH was performed on bone marrow obtained at the time of first visit to our institution or initial diagnosis. FISH probes were generated from specific BAC DNA clones for AHCYL1 gene locus (1p13.3) and CKS1B locus (1q21). MM cells were identified post-hybridization using isotype specific antibody conjugated with 7-amino-4-methylcoumarin-3-acetic acid (AMCA) to stain Ig-Kappa or Ig-Lambda light chain in cytoplasm (cIg) of myeloma tumor cells. The FISH signals in 100 myeloma cells were recorded. For this analysis, 3 copies of 1q21 are considered as 1q21 gain and ≥ 4 copies as 1q21 amp. A 20% cutoff point was used for detection of significant abnormalities, i.e. del 1p and 1q21 gain and amp. A multivariable logistic regression model was used to examine the combined effects of clinical variables on progression free (PFS) and overall survival (OS). Results- A total of 1133 patients were included in this analysis. The median age was 60 (range 30.2-75), 434 (38.3%) patients were female and 106 (9.4%) were African Americans. ISS stage III disease accounted for 287 (25.3%). GEP70 high-risk was noted in 160/1133 (14.1%) of all patients. Of all patients, 1084 (95.7%) had at least one ASCT and 812 (71.7%) had tandem upfront ASCT. Metaphase cytogenetic abnormalities were noted in 548 (48.4%). While del 1p was detected in 220 (19.4%) patients, 1q21 gain or amplification were observed in 300 (26.5%) and 150 (13.2%) patients, respectively. Isolated 1q21 gain and amplification without del 1p were seen in 235 (20.7%) and 121 (10.7%) patients. Overall, there was enrichment of high-risk features such as ISS stage III disease (5.7% vs 10.9% p=0.049), GEP70 high-risk (8.4% vs 36.8%), GEP 70 subtypes such as MF (4.6% vs 8.2%), MS (10.5% vs 13.6%) and PR (11.3% vs 22.7%) and abnormal cytogenetic abnormalities (45.7% vs 59.5% p= Conclusion: Deletion of short arm of chromosome 1p was observed in 19% of MM patients. Concomitant del 1p with 1q21 gain and /or amp was present in 8% of patients. The PFS and OS of patients with combined del1p/1q21gain abnormalities was significantly worse compared to del 1p alone and 1q21 gain alone and thus identifies a subset of patients with poor clinical outcome. Figure 1 Figure 1. Disclosures Mohan: Medical College of Wisconsin: Current Employment.

Idiopathic multicentric Castleman disease (iMCD) is a rare, life-threatening hematologic disorder involving multi-organ dysfunction driven by inflammatory cytokines, often including interleukin-6 (IL-6). The five-year overall survival rate varies considerably between cohorts, ranging from 50 to 77%. It is not well understood why administration of therapies such as the anti-IL-6 monoclonal antibody siltuximab induces complete and durable remission in some patients, whereas others succumb to their disease despite therapy. The aim of this study was to identify laboratory parameters associated with mortality in iMCD. To this end, iMCD patients enrolled in the ACCELERATE registry with fatal and non-fatal outcomes were compared. To determine differences in the laboratory profiles at time of diagnosis between the non-fatal (control) (n = 66) and fatal (mortality) (n = 6) iMCD groups, we performed two-tailed t-tests with Welch correction. P < 0.05 was considered significant. Due to the exploratory nature of this study and limited sample size, we did not perform correction for multiple comparisons among the 25 parameters assessed. In the fatal iMCD group, all patients were white, aged 15-66, and 33.3% were male. Four patients had a hypervascular histopathological subtype; one subtype was not stated, and one was mixed. The non-fatal iMCD group was mixed race and included 57.6% male patients; 38 patients had a hypervascular subtype, 19 had a mixed subtype, five patients had a plasmacytic subtype, three were not stated and one had a hyaline vascular subtype. The mean time from final diagnosis to death was 586.2 days (range: 16-2952 days). Around the time of diagnosis, immunoglobulin M (IgM) (Figure 1A), international normalized ratio (INR) (Figure 1B), and platelet count (PC) (Figure 1C) were significantly decreased in the fatal group compared with the non-fatal group (Figure 1D), with three mortality patients below the lower limit of normal (LLN) for IgM, and four mortality patients below the LLN for PC. Unlike the other two parameters, the INR levels were closer to normal in the fatal group than the non-fatal group. While C-reactive protein (CRP) levels were higher and hemoglobin (Hb) levels were lower in the mortality group, they did not surpass the significance threshold. These data provide new insights into differences between patients who have fatal and non-fatal outcomes. These preliminary findings from a small cohort of deceased patients demonstrate that patients with iMCD who have fatal outcomes may differ from those who do not. For instance, patients in the fatal group may be in a state of greater immune dysregulation (indicated by a lower IgM) and at increased risk of bleeding events (lower PC), compared with patients who go on to survive. The lower PC in the fatal group is likely reflective of patients with the recently-defined thrombocytopenia, anasarca, fever/elevated CRP, reticulin fibrosis/renal dysfunction, organomegaly (TAFRO) clinical subtype of iMCD having lower platelets and a more aggressive course. Thus, early evaluation of platelet count may be an early and actionable indicator of someone's likelihood of death. Additional research is needed into the role of PC and markers of inflammation and anemia in predicting mortality as well as the timing of decline of these markers. If validated in a larger cohort, certain laboratory values may be of use to identify patients at increased risk of death. Figure 1 Figure 1. Disclosures Kanhai: EUSA Pharma: Current Employment. Bagg: Scopio Labs: Research Funding. Lim: EUSA Pharma: Honoraria. Srkalovic: EUSA Pharma: Speakers Bureau; Takeda: Speakers Bureau; Foundation Medicine: Speakers Bureau; Janssen Pharmaceuticals: Speakers Bureau. Uldrick: Celgene: Research Funding; Merck: Other: Receives study drug; Roche: Research Funding; Regeneron: Current Employment. Fajgenbaum: EUSA Pharma: Research Funding; Pfizer: Other: Study drug for clinical trial of sirolimus; N/A: Other: Holds pending provisional patents for 'Methods of treating idiopathic multicentric Castleman disease with JAK1/2 inhibition' and 'Discovery and validation of a novel subgroup and therapeutic target in idiopathic multicentric Castleman disease'.

Key Clinical Message Concomitant diagnosis of metastatic prostate cancer and a multiple myeloma in older male patients is challenging as both malignancies are usually associated with bone lesions. Exact knowledge, experience, and an interdisciplinary approach are required in order to differentiate between both malignancies and determine the exact treatment strategy.

Myeloid sarcoma (MS) is characterized by extramedullary infiltration by immature myeloid cells. Owing to rarity of this disease, the clinical features and overall outcomes are yet to be clarified.To define clinical characteristics, epidemiology, pathologic findings, treatment options and outcomes in MS.We conducted a retrospective review of 23 patients diagnosed with MS at our institute over a period of 13 years (2002-2015).MS presented mostly as a manifestation of relapsed acute myeloid leukemia, seen in 39% of patients. Skin and subcutaneous soft tissues were the most common sites of anatomic involvement (69.5%). Ninety five percent (n = 19) were positive for classical myeloid markers with either cytochemical staining (chloracetate-esterase, MPO), flow-cytometry (CD33, CD34, CD13 and CD117), or immunohistochemistry (CD34, CD43, CD68 and lysozyme). Of these, 52% were positive for CD33 (n = 12), 35% for CD68 (n = 8), 30% for CD34 (n = 7), and 26% for lysozyme (n = 6). Cytogenetic abnormalities were seen in 63% (n = 12/19) patients on bone-marrow aspirate, with five patients displaying a complex (n = 3) or monosomal (n = 2) karyotype. Twenty seven percent patients with a normal karyotype had presence of deleterious mutations (FLT3, ASXL, STAG and JAK2) on further testing with myeloid mutation panel. The Median overall survival (OS) of the entire cohort was 15.9 months (95% CI, 7.4-24.4 months). The OS was significantly better for patients65 years (24.6 vs. 3.4 months, p = 0.009) of age, and for those attaining a complete remission (CR) to induction therapy (25.7 vs. 0.8 months, p 0.001). All patients who underwent allogeneic hematopoietic stem cell transplant attained long-term remissions, with a median follow-up of 54 (range 32-120) months.Failure to achieve CR with induction therapy, and age65 years are associated with poor outcomes in MS. Allogeneic stem-cell transplant in first remission appears to be the most effective modality for achieving long-term remissions.

Complete remission (CR) rates for multiple myeloma (MM) have increased to 60% with current treatment approaches, including high dose melphalan-based autologous stem cell transplant (ASCT) and novel agents, and are associated with improved survival.[1][1]–[3][2] Despite this improvement, highly

Key Clinical Message Amyloidomas of the head and neck region are uncommon and generally considered a benign localized form of amyloidosis. Here, we describe “the unusual case of a young man” with a nasopharyngeal mass and osteolytic lesions caused by systemic light‐chain amyloidosis treated successfully with a combined surgical and chemotherapy approach.

Castleman disease (CD) describes a spectrum of heterogeneous disorders defined by characteristic lymph node histopathology. Enlarged lymph nodes demonstrating CD histopathology can occur in isolation (unicentric CD; UCD) sometimes accompanied by mild symptoms, or at multiple sites (multicentric CD, MCD) with systemic inflammation and cytokine-driven multi-organ dysfunction. The discovery that Kaposi sarcoma herpesvirus/human herpesvirus (HHV)-8 drives MCD in a subset of patients has led to the hypotheses that UCD and MCD patients with negative HHV-8 testing by conventional methods may represent false negatives, or that these cases are driven by another virus, known or unknown. To investigate these hypotheses, the virome capture sequencing for vertebrate viruses (VirCapSeq-VERT) platform was employed to detect RNA transcripts from known and novel viruses in fresh frozen lymph node tissue from CD patients (12 UCD, 11 HHV-8-negative MCD [idiopathic MCD; iMCD], and two HHV-8-positive MCD) and related diseases (three T cell lymphoma and three Hodgkin lymphoma). This assay detected HHV-8 in both HHV-8-positive cases; however, HHV-8 was not found in clinically HHV-8-negative iMCD or UCD cases. Additionally, no novel viruses were discovered, and no single known virus was detected with apparent association to HHV-8-negative CD cases. Herpesviridae family members, notably including Epstein-Barr virus (EBV), were detected in 7 out of 12 UCD and 5 of 11 iMCD cases with apparent correlations with markers of disease severity in iMCD. Analysis of a separate cohort of archival formalin-fixed, paraffin-embedded lymph node tissue by In situ hybridization revealed significantly fewer EBV-positive cells in UCD and iMCD compared to tissue from HHV-8-positive MCD and EBV-associated lymphoproliferative disorder. In an additional cohort, quantitative testing for EBV by PCR in peripheral blood during disease flare did not detect systemic EBV viremia, suggesting detection lymph node tissue is due to occult, local reactivation in UCD and iMCD. This study confirms that HHV-8 is not present in UCD and iMCD patients. Further, it fails to establish a clear association between any single virus, novel or known, and CD in HHV-8-negative cases. Given that distinct forms of CD exist with viral and non-viral etiological drivers, CD should be considered a group of distinct and separate diseases with heterogeneous causes worthy of further study.

Introduction - Despite improvement in Multiple Myeloma (MM) therapy, most patients will eventually experience disease relapse. The course of relapsed MM can be quite heterogeneous with some patients achieving long-term disease control while others experience rapid successive relapses with short survival. Other than genetic features, there is currently a lack of prognostic markers to guide intensity and duration of therapy in relapsed MM. In the present study, we elucidate the prognostic value of minimal residual disease (MRD) and focal lesion assessment by PET-CT in relapsed patients. Methods- We investigated 120 MM patients that were diagnosed between 2000-2016 and treated on our Total Therapy (TT) 2-6 protocols, which incorporated multi-agent chemotherapy and tandem transplantation. All 120 patients had achieved a complete remission (CR) after TT and relapsed subsequently after a median of 5 years (0.9-18). Focal lesions were assessed with PET-CT in 112 patients at diagnosis and relapse. Other features investigated included gene expression analysis (GEP) defined by the UAMS GEP70 at diagnosis and relapse (n=75) and FISH at diagnosis (n=84). Once treatment for relapsed disease was initiated, response to therapy, including sequential measurement of MRD by conventional 8 color flow cytometry with a sensitivity of 10-5 was assessed at least every 6-12 months. MM therapy after progression was directed by the treating physician and consisted mostly of combination therapy of a Proteasome Inhibitor with an IMiD and Dexamethasone (62%) or a Daratumumab combination (25%) or other (13%). Results- Median age at first progression was 65 years and median follow up time was post-relapse was 19 months (range 2.2-65 months). High risk FISH features, including deletion 17p, 1q amplification, t(4;14) and t(14;16) were present in 29% (25/84) of the patients, but were limited in predicting worse PFS post-relapse (p=0.3) and OS (p= 0.5); 75 patients had GEP performed at diagnosis and relapse showing a significant increase (p Conclusion- Current clinical practice for relapsed MM incorporates mainly cytogenetic features that on their own seem to have limited predictive value. Our study suggests that risk classification and prognostication of relapsed MM can be significantly improved by using GEP and focal lesion assessment. Furthermore, achievement of MRD negativity should be the goal in relapsed MM therapy to improve clinical outcome. Disclosures van Rhee: EUSA: Consultancy; CDCN: Consultancy; Karyopharm: Consultancy; Adaptive Biotech: Consultancy; Takeda: Consultancy.

Key Clinical Message Assiduous surveillance for genetic aberrations is necessary in patients on cytotoxic therapies to detect therapy-related myeloid neoplasms (t-MN). Current modalities include metaphase cytogenetics and FISH. Since t-MN may develop abruptly in cytogenetically normal patients, a discussion exploring additional methods such as SNP-array and targeted-deep-sequencing to detect subchromosomal abnormalities is needed.

Introduction: Unicentric Castleman disease (UCD) is a rare non-clonal lymphoproliferative disorder affecting one lymph node station. UCD can be an incidental finding on radiologic studies, whilst other patients have symptomatology due to compression of vital structures. Surgical extirpation is the preferred therapy and is usually curative, but unresectable UCD can represent a therapeutic challenge. Castleman lymph nodes are often highly vascularized, which offers the opportunity for therapeutic embolization. We report a series of 6 patients with unresectable UCD who were treated with embolization either as sole therapy or supplemented by cryoablation and surgery. Methods: CT rotational angiography was performed to localize the arterial supply of UCD masses. Feeding vessels were selectively embolized using a 50:50 mixture of lipiodol and alcohol or 300-500 micron embospheres. A second arteriography was performed 2 to 3 months later to identify and embolize any new arterial channels. Results: Data is summarized in Table 1. Of a cohort of 47 patients with UCD, 6 (13%) were found to have symptomatic, unresectable disease. All patients were HIV and human herpesvirus-8 negative. The median patient age was 34 years (range: 28-34); five patients were male and one was female. Disease was localized to the pelvis (n=3), mediastinum (n=2), and axilla (n=1). In all but one case, the histology was of the hyaline vascular variety. Four patients had failed R-CHOP, rituximab/steroids, or both. In 2 patients, embolization was done as primary therapy, while 3 underwent additional surgery. In 5 patients, embolization was performed twice to ablate secondary arterial channels that had appeared after the first procedure. Adjunctive cryoablation at the time of embolization was applied in 2 patients. All treated patients had major reduction in their lymph node mass. The median reduction in tumor bulk was from 274cc (range:13-969) to 21cc (range: 3-394). One patient with an axillary mass involving the brachial plexus failed therapy and received radiation. A second patient had regrowth of the UCD and responded to combination lenalidomide and obinituzumab. Responses were sustained for at least 2 years in the remaining patients. Conclusion: A small number of case reports have been described UCD patients treated with arterial embolization as an immediate preoperative adjunct to surgery to limit intraoperative bleeding. In the present series, we utilized embolic devascularization to achieve cytoreduction rather than merely prevent surgical hemorrhage. Embolization was complemented by cryoablation and rendered surgery feasible. This case series highlights that effective disease control can be obtained of unresectable UCD using a multimodality approach in which vascular embolization plays a crucial role. Disclosures No relevant conflicts of interest to declare.

Introduction. Multicentric Castleman Disease (MCD) is an inflammatory disorder characterized by lymphadenopathy. The clinical course of MCD is variable; some patients have mild symptoms while others develop hypercytokinemia progressing to organ failure. Severely ill patients often have the TAFRO-variety of MCD characterized by Thrombocytopenia, Anasarca, Fever, Reticulin marrow fibrosis, and Organomegaly. We report on 76 MCD patients: the largest series from a single institution. Methods. Data was collected from our institution and outside records via systematic chart review and standardized survey for self-reported symptoms. Laboratory data represent each patient's most severe episode. TAFRO- and non-TAFRO or "classical" iMCD subtypes were grouped (iMCD) for some analyses. Patients were classified as POEMS-associated MCD when they had MCD with full POEMS syndrome or clear features of POEMS. Results. Forty-nine patients had classical iMCD and 12 TAFRO-iMCD. Fifteen patients had POEMS-associated MCD, of which 8 had coexistent POEMS syndrome. iMCD and POEMS-associated MCD had similar age and sex, but the hyaline vascular variant was more common in iMCD (44.3 vs 6.7%, p=0.006) (Table 1). iMCD patients were more symptomatic in terms of night sweats (61.0 vs 33.3%, p=0.001) and fever (50.8 vs 20%, p=0.031) compared to POEMS-associated MCD, but had similar laboratory characteristics and disease activity (CHAP) scores. TAFRO-iMCD patients were mostly male and had more fever (91.6 vs 42.9%, p=0.002), anasarca (100 vs 24.5%, p Commonly-used treatment regimens for iMCD were the anti-IL6/IL6 receptor antibodies siltuximab and tocilizumab (n=41), rituximab ± steroids (n=23), steroids alone (n=13), and chemotherapy (n=7). There was a high rate of response to anti-IL6 therapy (97%) with a treatment failure (TF) rate of 5%. Two further relapses occurred in patients who discontinued therapy. Steroid monotherapy or rituximab + steroids yielded response rates of 46 and 82%, but were marred by high TF rates (85 and 43%). Chemotherapy responses were noted in 7 instances, but TF occurred twice. There were no significant differences in response to therapy comparing the classical and TAFRO-iMCD groups, but both patients failing anti-IL6 therapy had TAFRO-iMCD. Six TAFRO-iMCD patients received chemotherapy and 2 relapsed. Six patients with POEMS and CD underwent autologous stem cell transplant with major improvement in polyneuropathy and MCD; 2 experienced relapse of their MCD and one died of late myelodysplastic syndrome. One improved post irradiation of a plasmacytoma and 1 died of progressive disease. Most MCD patients with POEMS features received rituximab-based therapies; 6/7 were alive and 1 died of sepsis. There was no difference in overall survival (OS) among the three groups (p=0.35) with a median OS of 5.65 years (4 - 9.2, 95% CI) in the iMCD group, 7.9 years (4.5 - 11.8, 95% CI) in POEMS-associated MCD, and 5.85 years (3.2 - 8.7, 95% CI) in the TAFRO group. The 5-year OS was 91%, 94% and 100% for the iMCD, POEMS-associated MCD and TAFRO groups, respectively. Conclusions. In a tertiary referral setting, excellent outcomes were achieved in all subgroups, likely attributed to highly selective therapeutic choices. Anti-IL6 therapy for iMCD was reserved for patients with active disease and laboratory evidence of inflammatory syndrome. Some TAFRO-iMCD patients achieved complete responses with anti-IL6 therapy, while others fared well with chemotherapy. Rituximab-based therapy was given to those with more indolent iMCD and those with POEMS-associated MCD. The polyneuropathy of POEMS benefitted most from transplant. Significant differences were noted in VEGF levels both in POEMS-associated MCD and TAFRO-iMCD compared to classical iMCD cases, with each cohort presenting a distinct clinical picture suggesting differing underlying etiologies and cytokine profiles. IL6 levels were not different among groups, though this may be confounded by effects of prior therapy. A better understanding of the pathobiology of the MCD continuum is essential to developing more targeted therapies. Disclosures No relevant conflicts of interest to declare.

Atypical chronic myeloid leukemia (aCML) is a rare chronic myeloproliferative disorder characterized by leukocytosis, absence of Philadelphia chromosome or BCR-ABL rearrangement, and marked myeloid dysplasia. The diagnosis of aCML is difficult and challenging, more so if the initial presentation is with blast crisis. In the absence of characteristic mutational profile, blast crisis of aCML can lead to significant diagnostic dilemma. We describe a case of refractory acute lymphoblastic leukemia (ALL), needing critical evaluation of hemopathological and cytogenetic abnormalities. It was hypothesized that patient had undiagnosed aCML and presented with lymphoid blast crisis. To our knowledge, this is the first described case of aCML presenting with lymphoid blast crisis.

As part of Total Therapy (TT) 3b, baseline marrow aspirates were subjected to two-color flow cytometry of nuclear DNA content and cytoplasmic immunoglobulin (DNA/CIG) as well as plasma cell gene expression profiling (GEP). DNA/CIG-derived parameters, GEP and standard clinical variables were examined for their effects on overall survival (OS) and progression-free survival (PFS). Among DNA/CIG parameters, the percentage of the light chain-restricted (LCR) cells and their cytoplasmic immunoglobulin index (CIg) were linked to poor outcome. In the absence of GEP data, low CIg 5.5 mg/l, a percentage of LCR cells exceeding 50%, C-reactive protein ⩾8 mg/l and GEP-derived high centrosome index. Further analysis revealed an association of low CIg with 12 gene probes implicated in cell cycle regulation, differentiation and drug transportation from which a risk score was developed in TT3b that held prognostic significance also in TT3a, TT2 and HOVON trials, thus validating its general applicability. Low CIg is a powerful new prognostic variable and has identified potentially drug-able targets.

Among the earliest invariant neuropathological changes in Alzheimer's disease (AD) is the degeneration of vulnerable hippocampal CA1 and subicular pyramidal neurons. Semaphorin 3A (Sema3A) is a secreted protein that functions in signaling growth cone collapse, chemorepulsion and neuronal apoptosis during early development of the central nervous system. In this report we show that accumulation of an internalized form of Sema3A is associated with degeneration of neurons in vulnerable fields of the hippocampus during AD. Accumulation of Sema3A overlaps the appearance of phosphorylated MAP1B and tau in many neurons, suggesting that Sema3A signaling at some level may be coupled to these previously identified cytoskeletal markers of neurodegeneration. Consistent with this, we isolated and partially characterized a multiprotein complex from the hippocampus of patients with AD that contains phosphorylated MAP1B, collapsin-response mediator protein 2 (CRMP-2), Plexins A1 and A2, and a processed form of Sema3A. A model is presented in which aberrant release of Sema3A from expressing neurons in the subiculum during AD results in the internalization and transport of Sema3A from this field to CA1. Within the context of the myriad of potential insults that contribute to Alzheimer's and other neurodegenerative diseases, the bioactivity of Sema3A may contribute either directly to neurodegeneration by inducing neuronal collapse, or indirectly by abrogating the recovery capabilities of adult neurons faced with these insults.

Introduction Achieving complete remission (CR) improves outcomes in multiple myeloma (MM). We have shown that 50% of patients enrolled in Total Therapy (TT) trials achieve CR within one year of enrollment irrespective of risk as defined by the GEP70 risk signature. Nevertheless, the majority of patients with high risk (HR) MM show an early relapse with grim prognosis, while most standard risk (SR) patients tend to relapse late, most often years after completion of maintenance therapy. Evaluation of minimal residual disease (MRD) has been shown to be of prognostic relevance in patients in CR with MRD negativity being associated with better outcomes. Here we report the impact of next generation sequencing (NGS)-based MRD assessment in TT patients who have achieved at least a very good partial response (VGPR) at two different time points during their treatment protocol: first after auto stem cell transplant (ASCT at 4-8 months of enrollment) and secondly during maintenance therapy (12-24 months). Materials and methods In brief, our TT protocols incorporate induction therapy consisting of Velcade and Thalidomide in conjunction with chemotherapy (Cisplatin, Doxorubicin, Cytoxan, Etoposide) followed by ASCT, consolidation and three years of maintenance with Velcade, Revlimid and Dexamethasone. HR and SR were assigned using the GEP70 risk signature. For MRD testing, we included 119 patients who were treated on our TT3b -TT6 protocols and who achieved at least VGPR and had bone marrow samples available at 4-8 months post ASCT and 12-24 months into maintenance. Thirty-eight patients had HR MM (32%), 75 patients had SR MM (63%) and no GEP70 data was available for 6 patients (5%). For NGS-based MRD assessment (Adaptive Biotechnologies Corp), genomic DNA was amplified using locus-specific primer sets for immunoglobulin heavy-chain complete (IGH-VDJH) and incomplete (IGH-DJ) as well as for immunoglobulin κ locus (IGκ). The amplified products underwent sequencing and clonal gene rearrangements were analyzed. MRD levels were calculated at a sensitivity level of 1 x 10-5. PET-CT and/or MRI were obtained at same time point as MRD assessment to evaluate presence of focal lesions. Results Using MRD status post-ASCT and during maintenance as a predictor, there were significant differences for PFS and OS in HR and SR MM. In HR disease, MRD positivity post ASCT was associated with significantly worse clinical outcomes with 2 year PFS/OS at 33% and 52% for MRD positive patients compared to 82%and 83% in MRD negative patients. Further 5 year PFS and OS for the same patient group were 11% and 24% for MRD positivity compared to 45% and 75% for HR patients that had achieved MRD negativity. In contrast to the HR group, there was no significant difference between MRD positivity and negativity in SR patients at the time point post ASCT we have investigated. In this latter patient group a significant difference only became obvious later during maintenance with 5 year PFS and OS at 55% and 63% for MRD positive patients compared to 83% and 93% for MRD negative patients. Of the 54 SR patients that were MRD positive post ASCT, 25 (46%) became negative later during maintenance, while in HR disease only 4 of 21 MRD positive patients post ASCT became negative during maintenance (19%). Importantly, a stratified analysis of our MRD data showed that even during maintenance the majority of cases in the favorable CD-2 subgroup were MRD positive, indicating that MRD results should further be interpreted in the context of patients' molecular subgroup. Conclusions Our data suggest that HR patients that do not achieve MRD negativity after their first ASCT have a very high likelihood of disease progression and death within 24 months. In contrast, SR patients that are still MRD positive post ASCT tend to have continuing response to treatment and MRD testing only becomes prognostic during maintenance. Of interest is that a high proportion of HR patients that achieve MRD negativity post ASCT and a smaller proportion of MRD negative SR patients still relapse within 5 years of enrollment suggesting that remaining residual MM cells are not detected by molecular MRD testing. Imaging studies with PET-CT and MRI could further stratify these patients as they detect any residual focal lesions that are not assessed by molecular MRD testing. We have combined PET-CT/MRI data for all of the 119 patients that were included in this study and analyzed data will be presented at ASH 2016. Disclosures Carlton: Adaptive Biotechnologies: Employment, Equity Ownership. Kong:Adaptive Biotechnologies Corp: Employment, Equity Ownership. Moorhead:Adaptive Biotechnologies: Employment. Barlogie:Signal Genetics: Patents & Royalties. Davies:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Morgan:Univ of AR for Medical Sciences: Employment; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Janssen: Research Funding.

Introduction Theachievement of Minimal Residual Disease (MRD) negativity has become a new standard of care for patients with multiple myeloma (MM). However the methods used for MRD detection, including multi-color flow-cytometry (MFC) and next generation sequencing (NGS), although both highly sensitive have different levels of sensitivity and are prone to a different range of errors. In addition MM is not distributed evenly through the marrow and biopsies are taken only from a single site. In contrast imaging studies using PET-CT can review an extended area and will detect focal lesions and extra-medullary disease. Studies incorporating all of these modalities are rare despite the importance of understanding how they perform together. We report on the comparison and clinical relevance of MRD testing by MFC, NGS and PET-CT in patients at different stages of their disease, including newly diagnosed MM (NDMM) as well as relapsed/refractory MM (RRMM) and in patients in long standing remission. Methods We investigated 100 patients, who all had at least achieved a VGPR and underwent MRD detection by 8 color MFC, NGS using the ClonoSEQ assay (Adaptive Biotechnologies Corp.) and imaging with PET-CT. Patients were at different disease stages and were categorized as either 1) undergoing upfront therapy for NDMM (n=53 including induction, post Stem Cell Transplant [SCT] and maintenance), 2) remission after completed therapy (n=32) or 3) RRMM (n=5). Detection thresholds were 1 MM cell in 105 using 8 parameter MFC and 1MM cell in 106 by NGS. Results Of the 100 patients analyzed, a myeloma clonal rearrangement was detected in 90 patients (90%). For patients with long-term MM history, clonal rearrangements could be identified in BM samples up to 13 years ago. Fifty-three of 90 patients (59%) were undergoing upfront therapy for newly diagnosed MM and the proportion of MRD negativity by MFC and NGS increased with treatment stage and was highest during maintenance. Of these 53 patients, six were undergoing induction therapy, none of them had achieved MRD negativity by MFC or by NGS. Eight patients were post-transplant and MFC was negative in 6 (75%) and 2 were negative by NGS (25%). Thirty-nine of the 53 patients were undergoing maintenance therapy. Of these 26 were negative by MFC (50%) and 17 (44%) by NGS. 32 of the 90 patients (35.5%) were off any therapy after achieving complete remission during treatment and completion of maintenance. MFC was negative in 19 of these 32 patients (60%), yet only 15 patients had an undetectable tumor burden by NGS (47%). For 14 patients with very long term remission (>5years) and who had remained off treatment for at least 2 years, MRD by MFC was negative in all of them and 11 showed no residual tumor burden by NGS (78.5%). Five patients were status post treatment for relapsed and refractory disease (5.5%). Of interest is that MRD burden by molecular analysis was overall very low, with 4 patients having Conclusions The study shows: 1) Almost half of patients who have achieved remission and completed treatment for NDMM are still MRD positive by NGS. Further evaluation will be necessary to determine whether MRD positivity in this patient population inevitably leads to clinical relapse and 6 months follow up of this patient population will be presented at ASH 2016. 2) The proportion of patients that achieve MRD negativity increases with treatment and is highest during and after maintenance. Detection of MRD should hence be measured sequentially throughout treatment to identify the time point of best response, which could further have an impact of overall prognosis. 3) Relapsed/refractory patients can present with non-secretory focal lesions without any significant MM burden on random aspirate. In these patients imaging studies, such as PET-CT, are crucial for the detection and monitoring of their disease. Disclosures Carlton: Adaptive Biotechnologies: Employment, Equity Ownership. Davies:Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Kong:Adaptive Biotechnologies Corp: Employment, Equity Ownership. Morgan:Univ of AR for Medical Sciences: Employment; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Janssen: Research Funding.

Background:After the positive results of the Quiredex trial suggesting a benefit in time to progression (TTP) and overall survival for high risk SMM patients treated with lenalidomide and low dose dexamethasone, significant attention has been paid to this patient-population as potential candidates for enrollment in clinical trials exploring early treatment intervention. This requires accurate patient selection, and the Pethema criteria to identify high risk SMM patients [those with >95% clonal plasma cells (PCs) within the total bone marrow (BM) PC compartment plus immune paresis] has raised some criticism due to the perception that MFC immunophenotyping is difficult to standardize. Although in spite of such limitations, the prognostic value of MFC in SMM has been reproduced by other groups, novel technological developments that could help standardizing MFC would be mostly welcomed. Aim: To develop a novel automated MFC classification algorithm to identify SMM patients at different risk of progression. Methods: A total of 270 SMM patients from two independent series were included in the present study; one from Spain (n=174) and another from Little Rock, Arkansas (n=96), hereafter named as GEM-SMM and UAMS-SMM. Median follow-up for each series was of 66 and 31 months, respectively. First, we started by determining the relative frequency of BMPCs plus the percentage of clonal and normal PCs within the whole BMPC compartment for each SMM patient. Since our aim was to discriminate within the total SMM population, those that phenotypically resemble (and clinically behave) like MGUS and like MM, each SMM patient was compared with a dataset containing information on the same three parameters from a total of 1419 patients, including 497 MGUS and 922 symptomatic MM. Using new EuroFlow software tools, principal component analysis (PCA) using those three parameters was then performed and shown by the automatic population separator (APS; PCA1 vs. PCA2) graphical representation of the Infinicyt software (Cytognos). On the basis of the APS view, MGUS and symptomatic MM patients were simultaneously grouped and defined by 1.5 standard deviation median borders, whereas for SMM patients each one of them became represented by a dot, and the first (x-axis) and second (y-axis) principal components were used to produce a bi-dimensional representation of patient profiles. Ultimately, each SMM case was plotted against the dataset, and the Infinicyt software automatically classified the patient as MGUS-, intermediate- or MM-like. Results: We started by investigating the prognostic impact of the novel and automated MFC algorithm in each of the two independent series. Among GEM-SMM patients, those classified as MM-like (n=26/174; 15%) showed significantly shorter median TTP than the remaining SMM cases (medians of 14 vs 73 months; HR: 3.5, P Conclusions: We developed a MFC computerized classification algorithm that as a single biomarker (without immune paresis), identifies SMM patients with high-risk of transformation to active MM. Importantly, this classification algorithm can be fully standardized (through automatized analysis of flow data) and as shown here, has the potential to be shared across different myeloma centers and potentially be used for selecting patients into clinical trials. Figure. Figure. Disclosures Paiva: Celgene: Honoraria, Research Funding; Janssen: Honoraria; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; EngMab: Research Funding; Amgen: Honoraria; Binding Site: Research Funding. Mateos:Takeda: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Celgene: Honoraria. Morgan:Univ of AR for Medical Sciences: Employment; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria. Barlogie:Signal Genetics: Patents & Royalties.

Multiple myeloma (MM) is a heterogeneous disease with high-risk patients progressing rapidly despite treatment. Various definitions of high-risk MM are used and we reported that gene expression profile (GEP)-defined high risk was a major predictor of relapse. In spite of our best efforts, the majority of GEP70 high-risk patients relapse and we have noted higher relapse rates during drug-free intervals. This prompted us to explore the concept of less intense drug dosing with shorter intervals between courses with the aim of preventing inter-course relapse. Here we report the outcome of the Total Therapy 5 trial, where this concept was tested. This regimen effectively reduced early mortality and relapse but failed to improve progression-free survival and overall survival due to relapse early during maintenance.

Multiple myeloma (MM) is a clonal plasma cell (PC) disorder characterized by end organ damage that is in turn characterized by CRAB criteria (calcium and creatinine elevation, anemia and bone lesions).1 It is commonly accepted that nearly all cases of MM are preceded by a clinically benign phase of monoclonal gammopathy of undetermined significance (MGUS) that evolves through a stage of smoldering multiple myeloma (SMM) without end organ damage,2 collectively referred to as asymptomatic monoclonal gammopathies (AMG).3 Although traditionally SMM is considered more prone to MM progression than MGUS, additional variables, such as involved-to-uninvolved free light-chain ratio4 and magnetic resonance imaging-defined focal lesion number and size,5 have been linked to progression to MM and form the basis for the newest International Myeloma Working Group criteria for MM.6 As the treatment of MM has been greatly advanced, emphasis has been placed on identifying patients with AMG at high risk of progression to MM so that, with earlier treatment, end organ damage can be minimized.7 Many new high-risk variables have indeed been identified such as level of circulating plasma cells8 and gene expression profiling (GEP).9, 10 We have previously reported that two-parameter flow cytometry of DNA and cytoplasmic light-chain immunoglobulin (DNA/CIG) is highly predictive of progression-free and overall survival in newly diagnosed MM treated with Total Therapy.11 In the current subset analysis of S0120, we have investigated whether the DNA/CIG assay can also identify patients with AMG at high risk for progression to MM requiring therapy (time to therapy, TTT).12 Of 254 patients enrolled at the University of Arkansas in the observational SWOG S0120 protocol with AMG, 110 had evaluable DNA/CIG information and retained AMG status according to the revised International Myeloma Working Group criteria for MM.6 All patients underwent detailed clinical staging as previously reported.9, 10 DNA/CIG assay was performed on whole bone marrow aspirates along with metaphase cytogenetics and GEP of CD138+ purified PC.13 Imaging studies involved metastatic bone surveys and, in the majority of the cases, magnetic resonance imaging examination of the axial and appendicular skeleton. Details of the DNA/CIG method have been published elsewhere.14, 15 A technical modification of the assay was applied uniformly since August 2006. The assay is based on the two-parameter flow cytometry of cytoplasmic immunoglobulin and DNA of whole bone marrow aspirates. Single-cell suspensions were exposed to anti-light-chain reagents (Dako Kappa and Lambda light chain F(AB)2/FITC conjugated) and then counterstained for DNA with propidium iodide with the addition of RNase. To quantitate the cellular DNA content, DNA index (DI)16 was determined and calculated as the ratio of the mean for each light-chain-positive G0/1 DNA peak divided by the mean of the light-chain-negative diploid G0/1 peak on the X axis. A DI between 0.99 and 1.01 was referred to as diploid, while hyperdiploid implied DI>1.01 and hypodiploid DI17% and CIg 17% and serum-M⩾3 g/dl; albumin

Introduction: Despite major advances in MM therapy with the inclusion of novel agent combinations for induction prior to and after autotransplant-supported high-dose melphalan, the 15% of patients with GEP-defined HRMM continue to fare poorly with PFS and OS not exceeding 2 and 3 years, respectively. This poor outcome has not been improved with less dose-intense and more dose-dense Total Therapy 5. Having previously reported on 16-day metronomic therapy with low-dose doxorubicin (DOX) and cisplatin (DDP) plus VTD (Papanikolaou, Haematologica), we explored further extension of such metronomic treatment to 28 days (metro-28) also in newly diagnosed HRMM patients. Patients and Methods: All patients signed a written informed consent and data analysis was approved by our IRB. In the outpatient setting, a single cycle of metro-28 comprised DOX and DDP each at 1.0mg/m2/d for 28d by continuous infusion (CI), along with VTD (bortezomib 1.0mg/m2 on days 1-4, 7-10, 13-16, 19-22, 25-28; DEX 12mg on days 1-4, 7-10, 13-16, 19-22, 25-28; thalidomide 50-100mg/d x 28d; some patients also received vincristine [VCR] at a flat daily dose of 0.07mg/d x 28d by CI. Results: Fourteen patients were initiated on metro-28. Their characteristics included age >=65y in 12; albumin 5.5mg/L in 7; cytogenetic abnormalities [CA] were present in 10; GEP70 HRMM in 9/13; PR subgroup in 8/13 (Table 1). The median follow up is 11mo. As portrayed in Figure 1A, no patient has died; the 6mo PFS estimate was 85% (Figure 1B); responses included CR in 3/14, VGPR in 7/14 and PR in 10/14 (Figure 1C); and the PR duration estimate at 6mo is 80% (Figure 1D). Of interest, GEP70 scores morphed to low risk in 3/13. Vascular density (CD34) decreased markedly in most patients evaluated. Toxicities were minor; myelosuppression was virtually absent; alopecia was not encountered. Subsequent salvage therapies included repeat metro-28, combination chemotherapy (PACMED) and autotransplants. Conclusion: We conclude that metro-28 is a promising and safe strategy for elderly patients with HRMM, and we hypothesize an anti-angiogenic mechanism of action in addition to direct anti-MM effects. Table 1. Patient characteristics Factor n/N (%) Age >= 65 yr 12/14 (86%) Albumin < 3.5 g/dL 8/14 (57%) B2M >= 3.5 mg/L 9/12 (75%) B2M > 5.5 mg/L 7/12 (58%) Hb < 10 g/dL 10/14 (71%) Cytogenetic Abnormalities 10/14 (71%) CA within 1 Year of Therapy 10/14 (71%) CA within 90 Days of Therapy 9/14 (64%) GEP 70-Gene High Risk 9/13 (69%) GEP PR Subgroup 8/13 (62%) GEP Proliferation Index >= 10 7/13 (54%) GEP Centrosome Index >= 3 7/13 (54%) n/N (%): n- Number with factor, N- Number with valid data for factor Figure 1. Figure 1. Disclosures Thanendrarajan: University of Arkansas for Medical Sciences: Employment. Alapat:University of Arkansas for Medical Sciences: Employment. Zangari:University of Arkansas for Medical Sciences: Employment; Onyx: Research Funding; Millennium: Research Funding; Novartis: Research Funding. Schinke:University of Arkansas for Medical Sciences: Employment. Heuck:Millenium: Other: Advisory Board; Janssen: Other: Advisory Board; Foundation Medicine: Honoraria; Celgene: Consultancy; University of Arkansas for Medical Sciences: Employment. van Rhee:University of Arkansa for Medical Sciences: Employment. Rosenthal:Cancer Research and Biostatistics: Employment. Epstein:University of Arkansas for Medical Sciences: Employment. Yaccoby:University of Arkansas for Medical Sciences: Employment. Davies:Janssen: Consultancy; Onyx: Consultancy; University of Arkansas for Medical Sciences: Employment; Millenium: Consultancy; Celgene: Consultancy. Morgan:MMRF: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; CancerNet: Honoraria; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Weismann Institute: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; University of Arkansas for Medical Sciences: Employment. Barlogie:University of Arkansas for Medical Sciences: Employment.

Background: Bing-Neel syndrome (BNS) or central nervous system (CNS) involvement in Waldenströms macroglobulinemia (WM) is rare and typically results from the infiltration of CNS by neoplastic lympho-plasmacytoid cells. The aim of this study is to present a review of the clinical characteristics, practices for treatment and overall prognosis of BNS. We present the largest systematic review to date of BNS cases reported in the literature. Material and Methods: A systematic review of PUBMED (http://www.pubmed.gov) was conducted to search for primary articles and case reports under keywords "Bing-Neel syndrome" and "Waldenströms macroglobulinemia", "leptomeningeal", "central nervous system", and "lympho-plasmacytoid cells". The search was extensive, ranging from 1955 to 2014. All adult cases written in English language were included. The search yielded 35 results and was individually examined by two authors. All studies that described hyperviscosity due to WM aside from BNS were excluded. The effect of regimens with high CSF penetration or intrathecal chemotherapy (IT) on overall survival (OS) was analyzed using Kaplan-Meier curves and Wilcoxon test. Results: This review summarizes the clinical characteristics and treatment modalities for 40 patients with BNS reported in the literature. The mean age at diagnosis was 62 years (range 36-82 years); 37.5% were females and 62.5% were males. Mean time from diagnosis of WM to BNS was 4.8 years, however about 10% (n=4) had neurologic symptoms due to BNS at the time of diagnosis of WM. The longest time from diagnosis of WM to BNS was 17 years. Patients presented with a wide spectrum of neurological symptoms and signs. Most common clinical manifestation was a progressive cognitive decline, seen in 43% (n=17) of patients. Other common presenting symptoms were acute or insidious neurologic deficits, memory impairment, persistent headaches and ataxic gait. Ninety percent of patients (n=36) had an elevated serum IgM (average 7.8 g/L), of which 97% (n=35) had IgM kappa, compared to 3% (n=1) with IgM lambda paraproteinemia. CSF lymphoplasmacytic pleocytosis was present in 89% (n=25/28) of patients, with a mean CSF WBC count of 76/µL at diagnosis. Most commonly these clonal B cells had an immune phenotype profile characterized by CD5+/-, CD10-, CD19+, CD20+, CD79b+, sIgM with light chain restriction (κ/λ). Tissue histology was performed in 55% (n=22/40) of cases and revealed either a diffuse perivascular or tumor like infiltration by small mature lymphocytes or lymphoplasmacytoid cells, immunohistochemically positive for CD20, surface IgM and light chain restriction. Radiographically, BNS presents either as a pseudo-tumoral form (mass lesions) or diffuse form (infiltration into cerebral parenchyma, cranial/spinal nerves or leptomeninges). Two-thirds (n= 30/40) of all cases presented with a diffuse pattern of CNS involvement, 15% (n=6/40) with pseudo-tumoral form, and 5% (n=2/40) had a combined diffuse and tumoral pattern. Magnetic resonance imaging (MRI) is the most sensitive imaging modality, used for diagnosis in 90% of patients (n=35/40). Characteristic findings on MRI are hyperintensities on T2 weighted imaging (diffuse or localized), increased signal intensity on FLAIR and diffusion weighted imaging with low ADC values. Mean time from diagnosis to death, reported in 15 publications, was 7 months (range: death during work up-2 years). Twenty patients were alive at last follow-up, with a mean time from diagnosis to last follow-up of 33.2 months (range 3 months - 14 years). Patients treated with multi-agent chemotherapy (R-DHAC, R-DT-PACE, FR,BR) along with IT chemotherapy (MTX or AraC) or CNS penetrating systemic therapy (HD MTX, RHyperCVAD), with or without RT or ASCT (3 patients only) had improved outcomes, with 71% (n=15/21) of such patients reported alive at last follow up (mean follow of 25 months). Median OS in this group was 19.6 months compared to 3.3 months (p=0.045) in patients receiving older systemic chemotherapy alone (cyclophosphamide, 2Cda, chlorambucil etc.), suggesting that CNS penetrating regimens may improve outcomes. Conclusion: BNS is a rare and aggressive complication of WM. Newer multi-agent chemotherapy combined with CNS penetrating systemic therapy or intra-thecal chemotherapy may improve outcomes. This study highlights an unmet need in this subset of patients with WM. Disclosures Atrash: University of Arkansas for Medical Sciences: Employment. Alapat:University of Arkansas for Medical Sciences: Employment.

Introduction Achieving complete remission (CR) improves survival outcomes in multiple myeloma (MM). Applying more sensitive flow-cytometry or PCR based minimal residual disease (MRD) testing further improves prognostication and MRD negativity confers better outcomes among CR patients. In our Total Therapy (TT) trials, gene expression profiling based risk (GEP) identifies 15% patients with high risk (HR) MM whose clinical course is characterized by early relapsing disease and prognosis has remained grim despite advances in therapy. Of interest is whether high-risk (HR) patients fail to achieve MRD negativity leading to relapse. We have determined response rates across the total therapy (TT) trials and in this study we report the impact of molecular negativity by MRD assessment in patients who have achieved at least very good partial response (VGPR) or CR at 4-8 months and 12-24 months, respectively, after enrollment in TT3b-TT5 from 2005-2009. We use next-generation sequencing (NGS)-based MRD assessment (Adaptive Biotechnologies) which is sensitive to 1 MM cell in 106 normal cells. Furthermore, we evaluate MRD status in long term relapse-free survivors (>6 years) to determine the importance of MRD status in prolonged remission. Materials and methods Study subjects include 591 patients enrolled in TT3b-TT5 to determine VGPR/nCR/CR by EBMT/IMWG criteria and to analyze PFS and OS of HR and SR patients defined by our GEP model. For MRD testing, we identified 102 patients from the TT3b-TT6 protocols that achieved at least VGPR and had bone marrow (BM) sample available at 4-8 months and 12-24 months after enrollment. Of these 102 patients, 14 patients had HR disease and 88 had SR. Six of 14 HR patients already had clinical relapse between 12-24 months, but were included to determine MRD at 4-8 months. Of all 102 patients, 51 are currently still in CR 6-9 years after protocol enrollment and most recent flow-cytometric MRD status was evaluated. NGS-based MRD Assessment: Genomic DNA was amplified using locus-specific primer sets for immunoglobulin heavy-chain complete (IGH-VDJH) and incomplete (IGH-VDH) as well as for immunoglobulin κ locus (IGκ). The amplified products were subjected to sequencing and clonal gene rearrangements were analyzed. Final MRD measurement was calculated at a sensitivity level of 1 cancer cell per 1 million cell equivalents. Flow Cytometry based MRD assessment: Erythrocyte-lysed BM samples were immunophenotyped by use of 8-color (CD138/CD38/CD19/CD45/CD27/CD81/CD56/CD20) staining technique. Myelomatous Plasmacells (PCs) were separated from healthy PCs by different phenotype expression and MRD was deemed negative when no myelomatous PCs were detectable at a sensitivity of Results Response by EBMT/IMWG criteria across our TT3b-TT5 (n=591) protocols showed no significant difference between HR and SR patients by year 1 of enrollment. In the SR group (n=502) 74.9%-77.9% of patients achieve at least nCR/VGPR and 40.3%-50.4% CR. For the HR patients (n=89) the results are similar with 75%-77.9% achieving at least VGPR and 50%-50.4% CR. However, the majority of HR patients start relapsing after one year of enrollment with a relapse rate of 59% for HR at 3 years compared to only 19% for SR at the same time point, indicating that MRD positive disease likely exists at 12-24 months for those patients with relapse. NGS-based MRD assessment will answer this question and data will be available by December 2015. Fifty one patients of the initial 102 patient group continue to be in complete remission to date >6 years after enrollment. Of these, 47 are MRD negative at a MRD level of 10-4. Conclusions Using conventional response methods, there is no difference between HR and SR MM at 1 year after initiation of treatment. However clinical outcome for HR disease is very poor and characterized by early relapsing disease, indicating that MRD persists even when patients have achieved CR. Sequencing is the most sensitive method for MRD detection and will be used in the present study to evaluate the importance of sequential MRD testing in HR and SR disease. We show that the majority of patients achieving long term remission at 6-8 years are MRD negative indicating the importance of molecular response for long term success. Disclosures Schinke: University of Arkansas for Medical Sciences: Employment. Mitchell:Cancer Research and Biostatistics: Employment. Faham:adaptive biotech: Employment, Other: stockholders. Patel:University of Arkansas for Medical Sciences: Employment. Thanendrarajan:University of Arkansas for Medical Sciences: Employment. Mohan:University of Arkansas for Medical Sciences: Employment. Mathur:University of Arkansas for Medical Sciences: Employment. Matin:University of Arkansas for Medical Sciences: Employment. Radhakrishnan:University of Arkansas for Medical Sciences: Employment. Stephens:University of Arkansas for Medical Sciences: Employment. van Rhee:University of Arkansa for Medical Sciences: Employment. Zangari:Novartis: Research Funding; Millennium: Research Funding; University of Arkansas for Medical Sciences: Employment; Onyx: Research Funding. Jethava:University of Arkansas for Medical Sciences: Employment. Petty:University of Arkansas for Medical Sciences: Employment. Alapat:University of Arkansas for Medical Sciences: Employment. Johnson:University of Arkansas for Medical Sciences: Employment. Epstein:University of Arkansas for Medical Sciences: Employment. Barlogie:University of Arkansas for Medical Sciences: Employment. Davies:Celgene: Consultancy; Onyx: Consultancy; Janssen: Consultancy; Millenium: Consultancy; University of Arkansas for Medical Sciences: Employment. Heuck:Millenium: Other: Advisory Board; Celgene: Consultancy; Janssen: Other: Advisory Board; Foundation Medicine: Honoraria; University of Arkansas for Medical Sciences: Employment. Hoering:Cancer Research and Biostatistics: Employment. Weinhold:University of Arkansas for Medical Sciences: Employment; Janssen Cilag: Other: Advisory Board. Morgan:Weismann Institute: Honoraria; MMRF: Honoraria; CancerNet: Honoraria; University of Arkansas for Medical Sciences: Employment; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

INTRODUCTION Profound osteolytic lesions are a hallmark of multiple myeloma (MM) bone disease. Bone destruction is associated with severely unbalanced bone remodeling, secondary to the secretion of osteoclast activating factors and significant osteoblast suppression. Lytic lesions of the pelvis are relatively common in MM patients and contribute to increase morbidity due to the high risk of fracture that frequently demands surgical intervention. Since we observed significant improvements in the pelvic CT of patients following total therapy 4 (TT4) we retrospectively analyzed the appearance on pelvic osteolytic lesions by CT during TT4 treatment for myeloma. METHODS The UAMS Myeloma data base was interrogated to identify patients enrolled on the TT4 trial. TT4 is a protocol designed for low risk MM patients as defined by a baseline plasma cell GEP score < than 0.66. The treatment protocol includes two induction chemotherapy cycles followed by tandem autologous bone marrow transplantation, two consolidation cycles and 3 years of maintenance. During treatment, patients were exposed to alkylating agents, IMIDS and proteasome inhibitor agents as well as bisphosphonates. Baseline pelvic osteolytic lesions with > 1 cm in minimal diameter identified by PET/CT or CT of the pelvis were compared to the most recent radiological study available for the same subject. All identified cases were reviewed by radiology faculty to confirm the baseline and follow-up reported findings. Radiological findings were correlated with disease status, molecular subgroup, PET scanning and MRI. RESULTS Sixty-three (63) patients, with a median age of 62 years, were identified for this analysis. Baseline patient characteristics are shown in Table 1. With a median follow up of 41 months, CT studies indicate that 44% (28/63) of patients with large baseline pelvic lytic lesions achieved re-accumulation of radio-dense mineralized tissue at the lytic site. Sixty-eight percent of such patients reached at least VGPR. The average size of the lytic lesions that re-mineralized was 4.0 cm (minimum 1.3 cm - maximum 10 cm). Baseline GEP-defined molecular subgroups and cytogenetic distribution was not different from the entire patient population of TT4. CONCLUSION This study clearly shows that mineral redeposition in large pelvic lytic lesions of MM patients on TT4 is achievable in a significant proportion of individuals. We observed that the amount of re-mineralization was prominent in pelvic lytic lesions with cortical bone destruction. Since flat bones, such as the pelvis, are formed via intramembranous ossification further investigation of the mechanism responsible for this effect is warranted at skeletal sites with different regenerative capacity. These data also suggest that, contrary to much dogma, MM bone lesions can regain matrix mineralization capacity. Table 1. Baseline Patient Characteristics n/N (%) Male 43/63 (69%) IgA Isotype 11/63 (17.5%) IgD Isotype 1/63 (1.6%) IgG Isotype 36/63 (57.1%) Nonsecretory 1/63 (1.6%) Light Chain Isotype 14/63 (22.2%) LDH > = 190 U/L 8/63 (12.7%) Abnormal Cytogenetics 44/63 (69.8%) GEP CD-1 subgroup 4/64 (6.3%) GEP CD-2 subgroup 17/64 (26.6%) GEP HY subgroup 24/64 (37.5%) GEP LB subgroup 8/64 (12.5%) GEP MF subgroup 1/64 (1.6%) GEP MS subgroup 2/64 (3.1%) GEP PR subgroup 5/64 (7.8%) Disclosures Mohan: University of Arkansas for Medical Sciences: Employment. Samant:University of Arkansas for Medical Sciences: Employment. Suva:University of Arkansas for Medical Sciences: Employment. Montgomery:University of Arkansas for Medical Sciences: Employment. Alapat:University of Arkansas for Medical Sciences: Employment. Morello:University of Arkansas for Medical Sciences: Employment. van Rhee:University of Arkansa for Medical Sciences: Employment. Waheed:University of Arkansas for Medical Sciences: Employment. Thanendrarajan:University of Arkansas for Medical Sciences: Employment. Schinke:University of Arkansas for Medical Sciences: Employment. Heuck:Millenium: Other: Advisory Board; Celgene: Consultancy; Foundation Medicine: Honoraria; Janssen: Other: Advisory Board; University of Arkansas for Medical Sciences: Employment. Jethava:University of Arkansas for Medical Sciences: Employment. Johann:University of Arkansas for Medical Sciences: Employment. Barlogie:University of Arkansas for Medical Sciences: Employment. Davies:University of Arkansas for Medical Sciences: Employment; Celgene: Consultancy; Janssen: Consultancy; Millenium: Consultancy; Onyx: Consultancy. Morgan:CancerNet: Honoraria; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; University of Arkansas for Medical Sciences: Employment; MMRF: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Weismann Institute: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Zangari:Novartis: Research Funding; Millennium: Research Funding; Onyx: Research Funding; University of Arkansas for Medical Sciences: Employment.

Background. The sensitivity of the MVista Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics) has been evaluated in disseminated histoplasmosis in patients with AIDS and in the ‘‘epidemic’’ form of acute pneumonia. Moreover, there has been no evaluation of the sensitivity of antigenemia detection in disseminated histoplasmosis after the implementation of methods to dissociate immune complexes and denature released antibodies. The goal of this study was to determine the sensitivity of the current antigen assay in different categories of histoplasmosis. Methods. Urine and serum specimens obtained from 218 patients with histoplasmosis and 229 control subjects, including 30 with blastomycosis, were tested. Results. Antigenuria was detected in 91.8% of 158 patients with disseminated histoplasmosis, 83.3% of 6 patients with acute histoplasmosis, 30.4% of 46 patients with subacute histoplasmosis, and 87.5% of 8 patients with chronic pulmonary histoplasmosis; antigenemia was present in 100% of 31 tested cases of disseminated histoplasmosis. Among patients with disseminated cases, antigenuria was detected more often and at higher concentrations in immunocompromised patients and those with severe disease. Specificity was 99.0% for patients with nonfungal infections (n 5 130) and in healthy subjects (n 5 69), but cross-reactivity occurred in 90% of patients with blastomycosis. Conclusions. The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.

Introduction: Bone disease in patients with paraproteinemias is typically associated to a diagnosis of of multiple myeloma (MM) and the presence of an IgM monoclonal gammopathy with associated lytic bone abnormalities always suggests the possibility of an IgM MM. Because Waldestrom’s Macroglobulinemia (WM) with lytic bone disease has also been reported in the literature we decided to retrospectively investigate the incidence of bone disease in patients carrying a diagnosis of WM and to evaluate the clinical relevant associations. Methods: After receiving IRB approvalwe retrospectively interrogated the UAMS Multiple Myeloma Data Base for cases of WM. From 01/01/1997 to 01/01/2014 a total of 167 subjects were identified and subsequently all cases reviewed by faculty hemopathologist to confirm diagnosis of WM.Within this cohort at baseline visit a total of 100 (61%) patients underwent MRI T1 and STIR sequences of head spine, pelvis, shoulder and sternum and 44 (27%) individuals received PET-CT scanning. Results: With a median age of 62 years (48-94), 61% of the subjects were male. Metaphase cytogenetic data were available in 146/164 (89%) of the cases at baseline, of which 38/146 (26%) were abnormal. Among the 100 patients who underwent baseline MRI examination 17(17%) had evidence of focal bone disease which was localized preferentially to the spine (11 cases) and the limbs (6 cases). Throughout the entire patient follow up PET-CT documented osteolytic lesions were described in 11 (24%) cases, 9 at baseline. Within the 109 patients with either MRI or PET-CT examination bone disease was reported in 23% of the subjects. With a median follow up of 10.9 years the median Overall Survival (OS) and Progression Free Survival (PFS) was 16.5 years and 15.9 years respectively. The presence of MRI bone focal lesions at baseline correlated with the presence of anemia (Hg Conclusion: To our knowledge this is the first study of bone disease in Waldenstrom’s patients by MRI and PET-CT. While PET-CT defined bone disease was present in 24% of the tested cases we could not identify significant correlation with clinical parameters. MRI defined bone disease was evidentin 17% of the patients retained a positive correlation with the presence of anemia (Hg Disclosures Barlogie: Celgene: Consultancy, Patents & Royalties, Research Funding; Millenium: Consultancy, Patents & Royalties, Research Funding. Zangari:Norvartis: Membership on an entity's Board of Directors or advisory committees; Onyx: Research Funding; Millennium: Research Funding.

Abstract 1225 Background: Secondary hemostatic defects resulting in bleeding diathesis occur in a subset of patients with plasma cell neoplasms due to a variety of mechanisms. Abnormal screening coagulation tests are frequently observed in asymptomatic patients with multiple myeloma and other plasma cell neoplasms. However, whether these coagulation abnormalities correlate with changes in serum proteins, diagnosis, or other disease parameters has not been systematically evaluated. Study Design: The objective of this study was to determine the prevalence of abnormal screening coagulation tests in patients with different plasma cell neoplasms and correlate clotting times with clinical history and diagnostic parameters. Methods: The medical records of 292 consecutive patients referred to the Myeloma Institute for Research and Therapy at UAMS from January 2010 to October 2010 were reviewed. Nineteen patients were excluded because they lacked screening coagulation tests or did not fulfill WHO diagnostic criteria for plasma cell neoplasm. Prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen activity were determined using mechanical detection. Abnormal APTT was defined as clotting times outside the normal range (23–36.9 sec). Prolonged PT was defined as ≥15.0 seconds (normal range: 11.5–14.7 sec) or INR > 1.2. Patients with prolonged PT or APTT due to warfarin therapy, liver disease or disseminated intravascular coagulation were also excluded. Results: A total of 79 patients had abnormal screening coagulation tests. An isolated prolonged PT was found in 62 patients (25%) and 10 patients had prolonged PT and APTT (3.5%). An isolated prolonged APTT was present in 2 patients ( Patients with isolated prolonged PT (62 total) and patients with normal screening tests (173 total) were compared with respect to age, fibrinogen, serum immunoglobulin level determined by protein electrophoresis, diagnosis, immunoglobulin isotype, and history of previous chemotherapy. There was no difference in age between patients with prolonged PT and those with normal PT (Table 1), previous chemotherapy or immunoglobulin isotype. Fibrinogen was significantly decreased in patients with prolonged PT (Table 1); however, there was no correlation between plasma fibrinogen and PT (p=0.1321). In contrast, serum immunoglobulin levels were significantly greater in patients with a prolonged PT (Table 1) and were positively correlated with PT (Figure 1). As shown in Table 2, prolonged PT was more frequently observed in patients with multiple myeloma while patients with MGUS were less likely to have prolonged PT. No differences were observed with other plasma cell neoplasms; however, the numbers of patients in these diagnostic groups was small. Conclusion: An isolated prolonged PT (≥15 sec) was the most common abnormal coagulation test in our cohort. An association between disease severity and prolonged PT is suggested by our finding that patients with multiple myeloma were more likely to have prolonged PT than were patients with other plasma cell neoplasms. Of the factors examined, only serum immunoglobulin levels correlated with PT and were significantly elevated in patients with isolated prolonged PT. Disclosures: No relevant conflicts of interest to declare.