Citations

Abstract Background: Limited information existed about the distributions of microbial etiology and drug-resistance with severe community-acquired pneumonia (CAP) in China, partly attributing to the antibiotics abuse in rearing livestock for Chinese farmers in recent decades. Moreover, the relevant guidelines have not been updated for at least a decade.Methods: A prospective observational study was carried out in Zhongshan Hospital (Shanghai, China). All consecutive cases of severe CAP diagnosed in Respiratory intensive care unit (ICU) and Emergency ICU were included. We assessed the microbial etiology features and multidrug-resistance (MDR) status. The risk factors were used by multivariate analyses for outcomes.Results: One hundred and twelve adults with severe CAP in ICUs, mean age of 65.7±15.1 years were studied. Etiological diagnoses were established in 76 (67.9%) cases; Klebsiella pneumoniae was the most frequent pathogen in 27 (35.5%) cases followed by Acinetobacter baumannii (n=15, 19.7%) and Methicillin-resistant Staphylococcus aureus (MRSA) (n=9, 11.8%); While Streptococcus pneumoniae (n=3, 3.9%) was ranked the 6 th in the study. The majority of pathogens were the MDR and the 30-days mortality rate was 43.8% in severe CAP patients. Klebsiella pneumoniae (OR, 6.88; 95%CI, 1.13-41.83), Sequential organ failure assessment (SOFA)≥5(OR, 12.30; 95%CI, 1.79-84.55) was associated to death.Conclusions: The study indicates a change in the usual pattern of microbiol etiology of severe CAP and the MDR emerged in the majority of pathogens over a decade in eastern China. Enhanced control of using antibiotics to reduce the acquired resistance is urgent.

Background: Progress in genome technology allows analysis of previously completed trials to identify subgroups potentially benefiting from therapy. Enzastaurin is a potent inhibitor of protein kinase C beta (PKC-β) and suppresses the phosphoinositide 3-kinase (PI3K)/AKT pathway. The safety and efficacy of Enzastaurin has been tested in more than 60 clinical trials including 2 major studies in DLBCL: (1) PRELUDE (A phase III maintenance trial of Enzastaurin vs Placebo, N=758) (Crump, 2016), and (2) S028 (A randomized phase II study of Enzastaurin/R-CHOP vs R-CHOP in frontline intermediate/high-risk DLBCL, N=101) (Hainsworth, 2016). DNA samples extracted from blood of patients from PRELUDE were retrospectively genotyped using whole genome SNP arrays. From the genome wide screening a novel genetic biomarker, DGM1, was identified showing high correlation with response to Enzastaurin treatment (Luo, ASH 2018). Importantly, these findings were replicated in the phase II S028 study. In the S028 study the hazard ratio (HR) for OS in high-risk (IPI ≥ 3) DGM1 positive (+) patients who received Enzastaurin/R-CHOP was 0.28 (0.1-0.81) when compared to subjects who received R-CHOP, a benefit favoring Enzastaurin (p=0.018). These data suggest that addition of Enzastaurin to R-CHOP may significantly improve outcome in frontline high-risk DGM1 (+) DLBCL. The ENGINE study was initiated to validate this finding in a prospective study. Study Design and Methods: Adult patients must have untreated CD20+ DLBCL, IPI ≥ 3. Patients are randomized 1:1 to Enzastaurin/R-CHOP or Placebo/R-CHOP for 6 cycles during combination phase. Each subject's treatment assignment will be unblinded after response assessment at the end of the combination phase. Subjects randomized to the investigational arm who have a complete or partial response will have the option to continue in the single agent phase to receive Enzastaurin for up to 2 additional years. The study intends to enroll approximately 235 patients with primary endpoint of OS in DGM1 (+) patients. The study is ongoing with 57 sites open in the US and China. As of 20 July 2019, 128 patients have been randomized. Clinical trial information: NCT03263026. Disclosures Nowakowski: Genentech, Inc.: Research Funding; Curis: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; F. Hoffmann-La Roche Ltd: Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; MorphoSys: Consultancy, Research Funding. Brody:Acerta Pharma: Research Funding; Merck: Research Funding; Celldex Therapeutics: Research Funding; Genentech: Research Funding; Oncovir, Inc.: Research Funding; BMS: Research Funding; Kite Pharma: Research Funding. Lue:Kymera Therapeutics: Honoraria; Astex Pharmaceuticals: Honoraria. Luo:Denovo Biopharma LLC: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Zhang:Denovo Biopharma LLC: Employment. Han:Denovo Biopharma LLC: Employment. Jivani:TRACON Pharmaceuticals, Inc.: Other: Stock; Denovo Biopharma LLC: Employment. Liu:Denovo Biopharma LLC: Employment. Li:Denovo Biopharma LLC: Employment. Sun:Novartis: Other: Stock; Denovo Biopharma LLC: Employment.

Introduction We have shown that in myeloma (MM) the immunomodulatory drugs (IMiDs) lenalidomide and pomalidomide, in a CRBN dependent fashion, inhibit thioredoxin reductase and thus increase intracellular oxidative stress as a consequence of peroxide accumulation (Sebastian et al. 2017). Accordingly, we have also shown that CRBN expression alone does not fully correlate with lenalidomide sensitivity, as the cells ability to decompose H2O2 is important - MM cells with lower H2O2 decomposition capacity are more sensitive to IMiDs. We hypothezised that the specific metabolic pathways used by cells for biomass production would influence IMiD sensitivity since they also influence this cellular oxidative capacity. Cellular proteins are key elements of this biomass, and required for the proliferation of MM cells and production of immunoglobulin proteins. Methods We cultured MM cells under various nutrients conditions to understand its effect on cell proliferation and drug responses. Cell viability was assessed by MTT assay, the Luminescent Assay, and direct cell counting. MM cells glycolytic rate was measured using the Seahorse XF analyzer. Western blots were performed to quantify various protein expression levels in MM cells cultured under different nutrients conditions. CRBN CRISPR/Cas9 KO plasmid was used to generate CRBN knockout cells and a lentivirus system was used to over-express CRBN in MM cells. Results MM cells resistant to lenalidomide, but still expressing functional CRBN, show a higher glycolytic pathway use than sensitive cells. We found that the lenalidomide sensitive cell line MM1.S is highly dependent on extracellular glutamine for cell proliferation. In contrast, JJN3, a lenalidomide resistant cells line with wild type CRBN, preferentially consumes glucose. We found that glutamine depletion from culture media completely abolished lenalidomide sensitivity in MM1.S cell line. Western blot analysis revealed that antibody production by MM1.S was primarily dependent on glutamine availability, and that JJN3 antibody production was dependent upon glucose availability. While glutamine depletion from culture medium completely abolished lenalidomide sensitivity in MM1.S cell line, IKZF1, and IKZF3 degradation was unchanged. We further studied the role of CRBN in glutamine dependent cellular biomass protein production using isogenic cell lines (+/- wtCRBN). We found that wtCRBN expressing cells proliferate more and show higher antibody production in the presence of glutamine, over CRBN negative isogenic cell lines. Lenalidomide treatment further increased glutamine dependent antibody production in wtCRBN expressing cells. One possibile explanation is that activation of glutamine catabolism can facilitate protein demethylation via the supplementation α-ketoglutarate (α-KG). Therefore, we tested whether lenalidomide treatment could induce protein demethylation in sensitive cell lines. Western blot probed with mono-methyl lysine antibody showed lenalidomide induced protein demethylation. We further confirmed that protein demethylation, and lenalidomide sensitivity is a consequence of elevated α-KG by treating cells with cell-permeable 5-octyl- α-ketoglutarate which act as a substrate of the lysine demethylases. 5-Octyl-α-ketoglutarate treatment inhibited cell proliferation preferentially in wtCRBN expressing cells, and also enhanced lenalidomide induced sensitivity. Protein demethylation is associated with protein ubiquitination and proteasomal degradation. We thus hypothesize that lenalidomide induced protein demethylation also likely increases proteasome inhibitors sensitivity in MM. Conclusion MM cells with preferential glutamine consumption are likely to be more sensitive to lenalidomide, and extracellular glutamine depletion can induce lenalidomide resistance. MM cells expressing CRBN, but not dependent on glutamine for protein biomass production are more likely to be resistant to lenalidomide. Our study postulates that CRBN protein requirement in lenalidomide sensitivity cells is restricted to high glutamine dependency, and that it is quite likely CRBN has a role in glutamine metabolism. Moreover, MM cells that consume more glutamine are under higher oxidative stress and exhibit less H2O2 decomposition capacity and therefore increasing sensitivity to IMiDs. References Sebastian , S., et al., Blood 2017 129:991-1007 Disclosures Stewart: Ono: Consultancy; Roche: Consultancy; Seattle Genetics: Consultancy; Takeda: Consultancy; Amgen: Consultancy, Research Funding; Bristol Myers-Squibb: Consultancy; Celgene: Consultancy, Research Funding; Ionis: Consultancy; Janssen: Consultancy, Research Funding; Oncopeptides: Consultancy. Bergsagel:Janssen Pharmaceuticals: Consultancy; Ionis Pharmaceuticals: Consultancy; Celgene: Consultancy. Fonseca:AbbVie, Amgen, Bayer, Celgene, Kite, Janssen, Juno, Merck, Pharmacylics, Sanofi, Takeda: Other: Consultant/Advisor; Prognosticatin of MM based on Genetic Categorization by FISH: Patents & Royalties; Adaptive Biotechnologies: Other: Scientific Advisory Board.

Introduction: Non-endemic Burkitt lymphoma (BL) is a rare and highly aggressive B-cell malignancy, of whom a substantial number are adolescents and young adults (AYAs). In this particular group of patients, the balance between efficacy and long-term toxicities is of major concern, due to the long expected remaining lifetime. In this study, we investigated the outcomes for AYA patients treated with intensive immunochemotherapy. Patients and methods: Patients were identified through queries to clinic based and population-based lymphoma registries from six countries (Australia, Canada, Denmark, Norway, Sweden, and USA). All diagnoses were confirmed by local investigators; patients with classical BL histology plus detectable MYC translocation, were included. Patients between 18 and 39 years of age at diagnosis treated with intensive immunochemotherapy (DA-EPOCH-R or more intensively) were evaluated in pre-specified age groups. All treatment protocols included rituximab. Overall survival (OS) was defined as the time from diagnosis until death from any cause or censoring, while event-free survival (EFS) was defined as the time from diagnosis until unplanned re-treatment, progression/relapse, death, or censoring, whichever came first. Response evaluation was assessed using established response criteria based on CT and/or PET/CT imaging. Survival curves were computed using the Kaplan-Meier estimator. The cumulative incidence of relapse in patients reaching complete remission (CR) or CR unconfirmed (CRu) was computed by Aalen-Johansen estimator. The 5-year restricted loss of lifetime (RLOL) was defined as the area between the patient and general population survival curves until 5-years. The general population survival was retrieved from publicly available lifetables stratified on age, sex, calendar year, and country. Results: In total, 108 AYA BL patients were included. The median age was 30 years, ranging between 18 and 39 and 82% were male. The majority had advanced stage disease (Ann Arbor stage III-IV, 76%), extranodal involvement (87%), and elevated LDH (67%). Seven patients (6%) had CNS involvement at the time of diagnosis. The chemotherapy regimens used were CODOX-M/IVAC (51%), BFM/GMALL (34%), hyper-CVAD (7%), DA-EPOCH (5%), and others (3%). Among 74 patients for whom data on tumor lysis were available, 10 (14%) developed clinical tumor lysis upon start of chemotherapy, all presenting with advanced stage and extranodal disease. The response rate was 91% (89 in CR/CRu and 2% in partial remission). At a median follow-up of 53 months, 15 had an event and 10 died. The 2-year OS and EFS for the total population was 92% (87-97%, Figure 1) and 88% (82-94%), respectively. For 13 patients aged 18-21 2-year OS and EFS were both 100%, while 2-year OS and EFS for 43 patients aged 22-30 were 98% (93-100%) and 93% (85-100%), respectively. The 2-year OS and EFS for patients aged 31-39 were 86% (76-96%) and 80% (69-91%), respectively. For patients in CR/CRu and available date of response evaluation, the 2-year post-remission OS was 99% (97-100%) and the 2-year relapse risk was 2% (0-5%), with no relapses after 6 months. Compared to the general population, the RLOL was 0.8 months (-0.5-2.2 months). Nine patients did not respond to primary treatment (SD or PD), all which belonged to the age group 31-40 years (P<0.001 versus age group 18-30 years). The oldest age group had an inferior OS compared to younger patients (P=0.008), largely due to non-responders having poor subsequent survival with a 1-year OS of 33%. Conclusion: The outcomes of AYA BL patients following intensive immunochemotherapy are excellent with high remission rates and low risk of relapse in general. However, even among young patients age remained prognostic, with patients 31 years or older having inferior OS and lower response rate to first-line treatment. In patients achieving CR, survival was similar to that of the general population over the median follow-up of 4.5 years, illustrating the need to focus on survivorship issues in these individuals. Figure 1: Overall survival for BL patients following intensive immunochemotherapy for all patients and for age groups (18-21, 22-30, and 31-39 years). Figure 1 Disclosures Jørgensen: Gilead: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Holte:Novartis: Honoraria, Other: Advisory board. Molin:Roche Holding AG: Honoraria; Merck & Co., Inc.: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda Pharmaceuticals: Honoraria. Ekstroem Smedby:Takeda: Honoraria, Other: Grant funding, Research Funding; Celgene: Honoraria, Other: Grant funding, Research Funding; Janssen Cilag: Honoraria, Other: Grant funding, Research Funding. Song:Takeda: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria; Amgen: Honoraria. Gerrie:Lundbeck, Seattle Genetics: Consultancy, Honoraria. Cheah:Roche, Janssen, MSD, Gilead, Loxo Oncology, Acerta, BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Other: Travel expenses; Celgene, Roche, Abbvie: Research Funding. El-Galaly:Roche: Employment, Other: Travel support; Takeda: Other: Travel support.

Background Bortezomib (BTZ) is highly effective in the treatment of multiple myeloma; however, emergent drug resistance is common. The underlying mechanisms of such proteasome inhibitor resistance are still incompletely understood. Methods To further understand its resistant mechanism, we generated eight multiple myeloma (MM) cell lines resistant to bortezomib (BTZ) by exposure to increasing drug concentration: five of them acquired novel PSMB5 mutations. Given the rarity of similar mutations in over 1,500 analyzed MM patients, we explored in depth the role of the proteasome on MM cell viability and BTZ sensitivity by systematically deleting the major proteasome targets of BTZ by CRISPR. Results We demonstrated that MM cell lines without PSMB5 were surprisingly viable (mutation corresponding yeast gene pre2 is lethal). PSMB5 mutated, BTZ resistant, MM cell lines were re-sensitized to BTZ when PSMB5 was experimentally deleted, implying that this mutation is activating in its drug resistance function. In contrast PSMB6 knockout was lethal to MM cell lines, which were efficiently rescued by re-introduction of wild type PSMB6. Interestingly, reduction in PSMB6 levels also prevented the splicing of the major catalytic subunits PSMB5, PSMB7, PSMB8 and PSMB10. PSMB6 engineered with no splicing function or catalytic activity, also restored viability, inferring that the contribution of PSMB6 to proteasome structure is more important than functional activity. Supporting this observation, BTZ sensitivity was restored in resistant MM cells line by introducing low level expression of mutated PSMB6 lacking splicing function. As with PSMB6, PSMB7 knockout was lethal to MM cell lines. In contrast, loss of immunoproteasome subunits PSMB8 and PSMB9 was neither lethal nor restored sensitivity to BTZ. Our results demonstrate that expression of the three constitutive proteasome subunits PSMB5, PSMB6 and PSMB7 is highly co-dependent. This dependence is relying on the structure, but not the function, of PSMB5 and PSMB6. Conclusions In summary, PSMB5 and PSMB6, but not PSMB8 and PSMB9, are highly relevant for BTZ sensitivity in MM. Absence of PSMB6 or PSMB7, but not PSMB5, was lethal in MM cell lines. Expression of PSMB5, PSMB6 and PSMB7 was highly co-dependent. Together these findings suggest that the modulation of expression rather than function of PSMB5, PSMB6 or PSMB7 may be a new therapeutic strategy. Disclosures No relevant conflicts of interest to declare.

Introduction: Emerging evidence supports that cytogenetic abnormalities (CAs) drive myelomagenesis and heterogeneity (e.g., clinical presentation, response to therapy, and prognosis) of multiple myeloma (MM). Diversity of CAs, including primary (IgH translocations and trisomies) and secondary CAs (copy number abnormalities) argues that MM is not a "single disease". Thus, identification of CAs at diagnosis is essential for risk stratification, guiding treatment, and prognostic estimation in daily practice. However, although frequency, configuration, and significance of CAs have been well documented in the Western countries, this information is lacking in the Asian population. To this end, a multi-center retrospective analysis was carried out to examine epidemiology and prognostic significance of CAs alone or in combination in a cohort of Chinese patients with newly-diagnosed MM (NDMM). Materials and Methods: A total of 1015 NDMM patients who had the baseline information of CAs detected by FISH at four institutes nationwide were included. According to the IMWG consensus updated in 2016, 1q gain, del(17p), t[4;14], and t[14;16] were defined as high-risk CAs (HRCAs), while another HRCA t[14;20] was not tested routinely in a majority of these patients. In addition, del(1p) and del(13q14) were considered as an adverse CA. According to the mSMART3.0 proposed by Mayo Clinic in 2018, double-hit (DHMM) and triple-hit MM (THMM) were defined as co-occurrence of 2 or >= 3 HRCAs, respectively. The Kaplan-Meier approach was used to estimate progression-free survival (PFS) and overall survival (OS). Results: In this cohort, the median age of 1015 patients was 61 years; 63.5% were male. The type of IgG, light chain, IgA, IgD, non/oligosecretory, IgM, or IgE accounted for 42.9%, 26.2%, 24.5%, 3.4%, 2.5%, 0.4%, and 0.1%, respectively. Del(13q) (46.4%) and 1q gain (46.1%; 3 copies = 73.8%, >= 4 copies = 26.2%) represented the most common CAs, followed by t(4;14) (14.0%), t(11;14) (11.8%), del(1p) (11.5%), del(17p) (9.9%; 20-50% cells = 35.6%, > 50% cells = 64.4%), and t(14;16) (5.1%). While none of these CAs was detected in 23.8% of cases, the frequency of patients who carried 1 - 5 CAs was 31.9%, 28.0%, 13.4%, 2.0%, and 0.9%, respectively. In the 1q+ cases, 36.4% patients carried second CA(s), including del(13q) (61.1%), t(4;14) (20.3%), del(1p) (14.8%), del(17p) (10.7%), t(11;14) (10.4%), and t(14;16) (8.1%). In the del(17p) cases, 57.5% patients had additional CA(s), including del(13q) (75.2%), 1q gain (49.5%), del(1p) (21.6%), t(4;14) (19.6%), t(14;16) (8.7%), and t(11;14) (2.2%). In the cases bearing IgH translocations, 26.0% patients also carried other CA(s), including del(13q) and 1q gain (61.9% for each), and del(17p) (9.3%). In the cases harboring HRCAs, the percentage of patients who carried 1 - 4 HRCAs was 70.2%, 24.8%, 3.7%, and 1.1%, respectively. Overall, 14.3% and 2.9% patients had DHMM or THMM, of whom 65.0%, 18.0%, 12.0%, and 5.0% had 2 - 5 HRCAs, respectively. While there was no significant difference in PFS between the cases carrying 1 and 2 CAs (P = 0.209), the patients who had 3 or more CAs displayed a sharp reduction in median PFS (P = 0.022 and P = 0.003 for 3 vs 1 or 2 CAs). Although multiple CAs was associated with shorter median OS, no statistical significance was observed for each comparison (P > 0.05). However, patients who carried >= 2 HRCAs had significantly shorter median PFS (12.1 months; P = 0.0004) and OS (29.3 months; P = 0.027) than those who had one single HRCA (32.2 and 65.6 months for median PFS and OS). Conclusion: In comparison with the Western countries, the incidence of secondary HRCAs (e.g., 1q gain and del(17p)) is relatively higher in Chinese patients at diagnosis, while the standard-risk CA such as t(11;14) is clearly less frequent. The proportion of Chinese patients who carry multiple CAs (up to 5) or HRCAs appear to be greater as well. In this context, patients carrying two or more HRCAs, so called DHMM or THMM, exhibit significantly worse outcome than those carrying only one HRCA. Together, this study builds up an up-to-date profile of CAs for Chinese patients, which might lay a foundation for revising the criteria for risk stratification and the guideline for treatment that is more feasible and practicable in China. It also provides the information about frequency and configuration of MM-driven CAs, which might be more relevant to the Asian population. Disclosures Kumar: Takeda: Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

Background: With the introduction of the Oncology Care Model, which aims to provide higher quality, more coordinated oncology care at the same or lower cost to Medicare, physician practices are increasingly being held accountable for performance and financial measures.1 Urgent care (emergency room [ER] visits and hospitalizations) is known to contribute a significant proportion of healthcare costs, and while there has been a focus on drug costs, little is known about the utilization or economic impact of urgent care among multiple myeloma (MM) patients. Objective: To identify the primary reasons and economic burden of ER visits and hospitalizations among newly diagnosed MM (NDMM) patients during first line of therapy (LOT1). Methods: Patients from the Optum Clinformatics Extended DataMart - Date of Death database (Optum DOD) with ≥1 medical or pharmacy claim for an NCCN listed MM treatment from 7/1/11 to 3/31/2018 (index date) were included if they had diagnosis code for MM (ICD9/10 code 203/C90) and ≥6-months continuous enrollment without MM treatment prior to index date. Patients were followed until death, end of eligibility, or end of study (9/30/2018), whichever occurred first. The top 20 most common primary diagnoses (PDx) for ER visits and for hospitalizations were identified separately for patients who received stem cell transplant (SCT) or not (nSCT) during LOT1. Total costs and per-patient-per-month (PPPM) costs of ER visits and hospitalizations for each PDx were reported. Results: Total 3,099 patients met inclusion criteria, including 2,761 (89.1%) nSCT and 338 (10.9%) SCT patients. nSCT patients were older than SCT patients (median nSCT=72 years vs SCT=62 years, p < 0.0001). The most common treatment regimens among nSCT were bortezomib in combination with dexamethasone (dex) (34%) followed by lenalidomide in combination with dex (27.4%). The most common treatment regimen among SCT were bortezomib in combination with lenalidomide and dex (46%) followed by bortezomib in combination with chemotherapy (18.3%). Median duration of LOT1 was 5.1 months among all patients, with median 11.2 months among SCT vs 4.5 months among nSCT, p < 0.0001). Among all patients, (Table 1) there was a total of 1,645 ER visits and 3,385 hospitalizations with a total cost of $3,729,208 and $56,751,758, respectively, and a PPPM cost of $146 and $2,220 for ER visits and hospitalizations, respectively. Among nSCT, there were 1,339 (81% of the total) ER visits and 2,776 (82% of the total) hospitalizations with a total cost of $3,063,727 and $39,763,095, respectively, and a PPPM cost of $151 and $1,955 for ER visits and hospitalizations, respectively. Among SCT, there were 306 (19% of the total) ER visits and 609 (18% of the total) hospitalizations, with a total cost of $665,481 and $16,988,663, respectively, and a PPPM cost of $127 and $3,253 for ER visits and hospitalizations, respectively. The most common PDx for hospitalizations among the entire cohort was 'MM, without mention of having achieved remission' with 769 hospitalizations for a total cost of $19,299,593 and a PPPM cost of $7,112. This same PDx was the most common among nSCT with 449 (58%) hospitalizations for a total cost of $7,551,282 and a PPPM cost of $9,292; as well as for SCT with 320 (42%) hospitalizations for a total cost of $11,748,760 and a PPPM cost of $4,435. This was also the most common PDx for ER visits among nSCT and SCT. For hospitalizations, the second most common PDx among the entire cohort and among nSCT was 'shortness of breath' while for SCT it was 'administration of antineoplastic chemotherapy'. The second most common PDx overall and for nSCT for ER visits was 'chest pain' and for SCT patients was 'musculoskeletal dysfunction (Segmental and somatic dysfunction of cervical region)'. Conclusions: In this analysis, NDMM patients experienced frequent ER visits and hospitalizations over a median of ~5 months for a total cost of more than $60 million, with most of the cost among nSCT patients. The most common PDx was related to MM. Even though some hospitalizations for the SCT patients may have been for the SCT procedure itself, the economic burden of urgent care for MM patients remains very high. Additional research to assess the impact of newer treatments on urgent care visits among NDMM, identify patients at high risk of urgent care visits may provide insight into the potential for developing cost-saving interventions to reduce the utilization of urgent care. Disclosures Maiese: Janssen: Employment, Equity Ownership. Zhu:Janssen Scientific Affairs, LLC: Other: contractor for Janssen. Wu:Janssen: Employment, Equity Ownership. Chen:Janssen: Employment, Equity Ownership. Ailawadhi:Janssen: Consultancy, Research Funding; Takeda: Consultancy; Celgene: Consultancy; Cellectar: Research Funding; Amgen: Consultancy, Research Funding; Pharmacyclics: Research Funding.

Abstract Context Prognosis of metastatic pheochromocytoma/paraganglioma following 131-Iodine metaiodobenzylguanidine (MIBG) is incompletely characterized due to small samples and shorter follow-up in these rare, often indolent tumors. Objective To describe long-term survival, frequency, and prognostic impact of imaging, biochemical, and symptomatic response to 131-I MIBG. Design Retrospective chart and imaging review at a tertiary referral center. Patients Six hundred sixty-eight person-years of follow-up in 125 patients with metastatic pheochromocytoma/paraganglioma with progression through prior multimodal treatment. Intervention Median 18 800 MBq 131-I MIBG. Main Outcome Measures Overall survival, Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST) imaging response, symptomatic response per chart review, and biochemical response (20% change over 2 consecutive assays of catecholamines, vanillylmandelic acid, metanephrines, or chromogranin A). Results Median survival standard deviation [SD] from diagnosis was 11.5 years [2.4]; following metastasis, 6.5 years [0.8]; post treatment, 4.3 years [0.7]. Among 88 participants with follow-up imaging, 1% experienced complete response, 33% partial response, 53% stability, and 13% progression. Fifty-one percent showed subsequent progression, median progression-free survival [SD] of 2.0 years [0.6]. Stability/response vs progression at first imaging follow-up (3–6 months) predicted improved survival, 6.3 vs 2.4 years (P = 0.021). Fifty-nine percent of 54 patients demonstrated biochemical response. Fifty percent of these relapsed, with median time to laboratory progression [SD] of 2.8 years [0.7]. Biochemical response did not predict extended survival. Seventy-five percent of 83 patients reported improvement in pretreatment symptoms, consisting primarily of pain (42%), fatigue (27%), and hypertension (14%). Sixty-one percent of these patients experienced subsequent symptomatic progression at median [SD] 1.8 years [0.4]. Symptomatic response did not predict extended survival. Conclusions Imaging, symptomatic, and laboratory response to multimodal treatment including high-dose 131-I MIBG were achieved on long-term follow-up in metastatic pheochromocytoma or paraganglioma. Imaging response at 3 to 6 months was prognostic.

Abstract The current view is that treatment failures of AML patients are due to persistence of leukemia stem cells (LSCs). The presence of FMS-like tyrosine kinase-3 (FLT3) Internal tandem duplication (ITD) is associated with poor prognosis. But, FLT3 tyrosine kinase inhibitors (TKI) demonstrate transient clinical activity in FLT3-ITD+ AML patients. Persistent FLT3-ITD+ AML LSC represent a source of relapse. There is a pressing need to target LSC and improve outcomes for FLT3-ITD+ AML patients. PRMT1, the predominant arginine methyltransferase, has been implicated in pathogenesis of AML rare subtype (i.e., acute megakaryoblastic leukemia). Herein, we show that PRMT1 protein expression is significantly increased in LSC-enriched AML CD34+CD38- cells relative to the counterparts of normal peripheral blood stem cells (PBSC) (AML n=9, normal n=8, p=0.0004,). Following PRMT1-knockdown (KD), AML CD34+ cells (n=15) demonstrated varying degrees of apoptosis while the survival of normal cells were not affected. Interestingly, we observed significant apoptosis-induction in a subset of samples bearing FLT3-ITD mutation (6 out of total 15) upon PRMT1-KD (ShCtrl 13.9±3.6%, ShPRMT1 32.5±4.6%, p<0.001). PRMT1-KD induced apoptosis was also more evident in cord blood (CB) CD34+ cells expressing FLT3-ITD (ShCtrl 19.4±1.3%, ShPRMT1 45.2±2.5%, p<0.001) relative to that of FLT3-WT (ShCtrl 27.47±1.8%, ShPRMT1 36.9±1.6%, p=0.0167). In 293T cells ectopically overexpressing FLT3-WT or FLT3-ITD, co-immunoprecipitation (co-IP) indicated greater interaction between PRMT1 and FLT3-ITD. Through RNA-Seq profiling two AML lines (MV4-11, OCI-AML3) plus one FLT3-ITD transduced CB CD34+ cells with PRMT1-KD, we obtained a differentially-regulated gene set as a "PRMT1 signature". This signature was enriched in FLT3-ITD+ AML relative to FLT3-WT AML according to ssGSEA analysis using two AML datasets (GSE14468, GSE10358), indicating PRMT1 may cooperate with FLT3-ITD regulating AML maintenance. Given that PRMT1 directly interacts with FLT3-ITD, we next asked whether PRMT1 catalyzes FLT3-ITD protein methylation. Through mass-spectrometry analysis of a FLT3-ITD+ AML specimen and in vitro methylation assay, we identified that PRMT1 catalyzes FLT3-ITD arginine (R) methylation (Me) at two conserved residues, 972 and 973. Using in-house R972/973 Me antibody, we validated the expression of FLT3 R-Me in FLT3-ITD AML speciemens (7 out of 7). To test R-Me function, we transduced MLL-AF9 (MA9) overexpressing murine c-Kit+ cells with methylation-deficient FLT3-ITD (R972/973K, arginine [R] to lysine [K]) construct, and found that MA9 cells expressing R972/973K underwent more apoptosis than that of WT FLT3-ITD (WT FLT3-ITD 9.7±1.1%, R972/973K 23.7±2.1%, p=0.003). The double transformed cells were further transplanted into recipients for leukemia development. Mice receiving MA9 cells expressing R972/973K exhibited longer survival (median survival: WT FLT3-ITD 36 days, R972/973K 50 days, p=0.002, n=6). Mechanistically, expression of R972/973K did not affect the total tyrosine phosphorylation level of FLT3-ITD. Additionally, FLT3-ITD R-Me expression persisted after a TKI (AC220) treatment. These facts indicated that FLT3-ITD R-Me function is independent of FLT3-ITD kinase activity. We then used a FLT3-ITD+ patient derived xenograft (PDX) model to assess the effects of TKI and PRMT1 inhibition. Following engraftment >1% in peripheral blood, we divided mice (n=24) into 4 groups and treated each with vehicle, MS023 (a type I PRMT inhibitor, ACS Chem Biol. 2016;11:772-781) (160 mg/kg/i.p), AC220 (10 mg/kg/i.g) or combination for 4 weeks. MS023 treatment downregulating FLT3 R-Me levels enhanced elimination of FLT3-ITD AML cells by AC220 treatment (AC220 24.6±13.4% vs combination 7.6±6.5%, p=0.02, n=6). At 16 weeks post-secondary BMT, significant AML burden in single drug treated transplants was observed, but less AML cells were detected in combination-treated transplants (AC220 52.3%, vs combination 25.4%, p<0.001, n=6). MS023 had little effect on long-term in vivo engraftment of CD34+ from a human CB specimen (vehicle 76.3±5.9%, MS023 72.2±3.4%, p=0.21, n=5). In summary, our study demonstrated PRMT1 overexpression contributes to AML stem/progenitor cell survival possibly through FLT3-ITD methylation, supporting further exploration into how PRMT1-mediated FLT3 methylation governs LSC survival. Disclosures Khaled: Alexion: Consultancy, Speakers Bureau; Daiichi: Consultancy; Juno: Other: Travel Funding.

Abstract The first two authors and last two authors contributed equally. Genome-wide association studies (GWAS) have identified risk loci for Acute Lymphoblastic Leukemia (ALL), Chronic Lymphoblastic Leukemia (CLL) and Non-Hodgkin Lymphoma, however an Acute Myeloid Leukemia (AML) GWAS has not been published to date. We performed a GWAS to identify AML and Myelodysplastic Syndrome (MDS) risk loci using a nested case-control study design in the DISCOVeRY-BMT cohorts which includes almost 2000 AML and MDS patients as cases and 2813 unrelated donors as controls. Genotyping was performed using the Illumina Human OmniExpress BeadChip and imputed using the Haplotype Reference Consortium, yielding > 8 million high-quality variants for statistical analysis. Logistic regression models with AML (de novo AML with normal cytogenetics, de novo AML with abnormal cytogenetics and therapy-related AML) and MDS cases and European American healthy donor controls adjusted for age and sex were used to test the association of each SNP with disease status. To identify the strongest association signal with disease we conducted a summary statistic SNP-based association analysis (ASSET) using non-overlapping AML and MDS cases implemented in R statistical software. ASSET uses an exhaustive search for SNPs with small but common pleiotropic effects across groups of traits while accounting for the multiple tests required by the subset search, as well as any shared controls between groups. This approach allowed us to further investigate the heterogeneity within AML subtypes and to gain increased power by pooling subtypes that show pleiotropic effects. ASSET genome wide (GW) significance is defined as P<5.0x10-8, however, we present results of each subset analysis. ASSET analyses identified an association of T allele at rs12203592, Interferon Regulatory Factor 4 (IRF4), with increased risk of de novo AML and MDS (Figure 1) (OR=1.37; 95% CI, 1.25-1.51, Pmeta=1.59x10-10). The variant has been reported significant in GWAS of skin pigmentation, hair color, non-melanoma skin cancer, squamous cell carcinoma, actinic keratosis, and childhood ALL; GW case-control studies of neuroblastoma and breast cancer show suggestive association signals (P<5 x 10-6). IRF4 belongs to the IRF family of transcription factors and is a key regulator of differentiation stages in hematopoiesis. The T allele at rs12203592 is associated with significantly increased expression of IRF4 in whole blood and lung tissue and in vitro mouse studies have shown the T allele to be associated with higher levels of IRF4 transcription. rs12203592 is <80bp from an IRF4 transcription start site and in an important position within NF-κB motifs in multiple blood and immune cell lines, supporting the hypothesis that this SNP modulates NF-κB repression of IRF4 expression. Another variant in the IRF4 regulatory region, rs62389423 (A allele), showed a putative association with subsets of de novo AML and MDS (OR=1.36; 95% CI,1.21-1.52, Pmeta=1.2x10-7). Although not in linkage disequilibrium with rs12203592, the A allele has also been previously associated with susceptibility to skin cancer and melanoma in multiple GWAS. Analysis of 596 UKbiobank CLL cases and >300,000 controls, shows the A allele correlates with a 50% increased risk of CLL (95% CI, 1.32-1.73, P= 2.4x10-9).Several other GWAS also show an association between additional IRF4 variants and CLL. Analyses in individual subtypes also revealed an intronic variant, rs10098598, in RAD21 to be associated with de novo AML (OR=2.18; 95% CI, 1.60-2.97; Pmeta=8.9x10-7). RAD21, on8q24, a region known to be associated with multiple cancer types, is involved in DNA double-stranded break repair and in chromatid cohesion in mitotic cells. Loss of function would theoretically lead to chromosomal instability and tumorigenesis. Components of the cohesion complex (including RAD21) are somatically mutated in ~12% of de novo AML and MDS patients, where it is frequently an early event. We provide the first GW evidence of association between a common variant and AML susceptibility. This SNP has been shown to be associated with multiple phenotypes, suggesting that there are pleiotropic effects at work. Our RAD21 finding is consistent with the role of cohesion in leukemogenesis and provides some evidence of its role in de novo AML susceptibility. Replication and further subset analyses with genome-wide data in >2000 AML cases are ongoing. Disclosures Griffiths: Alexion Inc.: Honoraria, Research Funding; Astex/Otsuka Pharmaceuticals: Honoraria, Research Funding; Celgene, Inc: Honoraria, Research Funding; Novartis, Inc.: Research Funding; Pfizer, Inc.: Research Funding. McCarthy:Bristol Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria.