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Background: Inflammation is important in multiple myeloma pathogenesis, and regular aspirin use has been shown to confer a reduced risk of multiple myeloma. The influence of aspirin on survival after multiple myeloma diagnosis is unknown. Methods: We identified 436 men and women diagnosed with multiple myeloma between 1980 and 2016 in the Health Professionals Follow-up Study and the Nurses' Health Study who reported aspirin intake biennially on follow-up questionnaires. Using multivariable Cox proportional hazards regression models, we estimated HRs and 95% confidence intervals (CI) associated with the effect of aspirin use on multiple myeloma–specific and overall mortality. Results: Compared with nonusers, participants who used aspirin after diagnosis had a multivariable HR for multiple myeloma–specific mortality of 0.61 (95% CI, 0.46–0.79) and for overall mortality of 0.63 (95% CI, 0.49–0.80), after adjustment for age at diagnosis, year of diagnosis, sex, body mass index, prediagnosis aspirin use, and number of comorbidities. For postdiagnosis aspirin quantity, we observed a modest trend of reduction in multiple myeloma–specific and all-cause mortality with increasing number of 325-mg tablets of aspirin per week, although the CIs for 1 to Conclusions: These findings support the use of aspirin as a complementary strategy to enhance multiple myeloma survival. Impact: Confirmation in samples that have comprehensive clinical information is encouraged.

The development of novel agents has transformed the treatment paradigm for multiple myeloma, with minimal residual disease (MRD) negativity now achievable across the entire disease spectrum. Bone marrow–based technologies to assess MRD, including approaches using next-generation flow and next-generation sequencing, have provided real-time clinical tools for the sensitive detection and monitoring of MRD in patients with multiple myeloma. Complementary liquid biopsy–based assays are now quickly progressing with some, such as mass spectrometry methods, being very close to clinical use, while others utilizing nucleic acid–based technologies are still developing and will prove important to further our understanding of the biology of MRD. On the regulatory front, multiple retrospective individual patient and clinical trial level meta-analyses have already shown and will continue to assess the potential of MRD as a surrogate for patient outcome. Given all this progress, it is not surprising that a number of clinicians are now considering using MRD to inform real-world clinical care of patients across the spectrum from smoldering myeloma to relapsed refractory multiple myeloma, with each disease setting presenting key challenges and questions that will need to be addressed through clinical trials. The pace of advances in targeted and immune therapies in multiple myeloma is unprecedented, and novel MRD-driven biomarker strategies are essential to accelerate innovative clinical trials leading to regulatory approval of novel treatments and continued improvement in patient outcomes.

Recent insight in the genomic landscape of newly diagnosed multiple myeloma (NDMM) and its precursor conditions, monoclonal gammopathy of uncertain significance (MGUS), and smoldering myeloma have allowed the identification of patients with precursor conditions with a high risk of progression. These cases with “progressor” MGUS/SMM have a higher average mutation burden, have higher rates of mutations in specific genes such as MAPK, DNA repair, MYC, DIS3, and are enriched for specific mutational signatures when compared to non-progressors and are comparable to those found in NDMM. The highly preserved clonal heterogeneity seen upon progression of SMM, combined with the importance of these early variables, suggests that the identification of progressors based on these findings could complement and enhance the currently available clinical models based on tumor burden. Mechanisms leading to relapse/refractory multiple myeloma (RRMM) are of clinical interest given worse overall survival in this population. An Increased mutational burden is seen in patients with RRMM when compared to NDMM, however, there is evidence of branching evolution with many of these mutations being present at the subclonal level. Likewise, alterations in proteins associated with proteosome inhibitor and immunomodulatory drugs activity could partially explain clinical resistance to these agents. Evidence of chromosomal events leading to copy number changes is seen, with the presence of TP53 deletion, mutation, or a combination of both being present in many cases. Additional chromosomal events such as 1q gain and amplification may also interact and lead to resistance.

PURPOSE Smoldering multiple myeloma (SMM) is a precursor condition of multiple myeloma (MM) with a 10% annual risk of progression. Various prognostic models exist for risk stratification; however, those are based on solely clinical metrics. The discovery of genomic alterations that underlie disease progression to MM could improve current risk models. METHODS We used next-generation sequencing to study 214 patients with SMM. We performed whole-exome sequencing on 166 tumors, including 5 with serial samples, and deep targeted sequencing on 48 tumors. RESULTS We observed that most of the genetic alterations necessary for progression have already been acquired by the diagnosis of SMM. Particularly, we found that alterations of the mitogen-activated protein kinase pathway ( KRAS and NRAS single nucleotide variants [SNVs]), the DNA repair pathway (deletion 17p, TP53, and ATM SNVs), and MYC (translocations or copy number variations) were all independent risk factors of progression after accounting for clinical risk staging. We validated these findings in an external SMM cohort by showing that patients who have any of these three features have a higher risk of progressing to MM. Moreover, APOBEC associated mutations were enriched in patients who progressed and were associated with a shorter time to progression in our cohort. CONCLUSION SMM is a genetically mature entity whereby most driver genetic alterations have already occurred, which suggests the existence of a right-skewed model of genetic evolution from monoclonal gammopathy of undetermined significance to MM. We identified and externally validated genomic predictors of progression that could distinguish patients at high risk of progression to MM and, thus, improve on the precision of current clinical models.

Prevalence estimates for monoclonal gammopathy of undetermined significance (MGUS) are based on predominantly White study populations screened by serum protein electrophoresis supplemented with immunofixation electrophoresis. A prevalence of 3% is reported for MGUS in the general population of European ancestry aged 50 years or older. MGUS prevalence is two times higher in individuals of African descent or with a family history of conditions related to multiple myeloma. We aimed to evaluate the prevalence and clinical implications of monoclonal gammopathies in a high-risk US population screened by quantitative mass spectrometry.We used quantitative matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry and EXENT-iQ software to screen for and quantify monoclonal gammopathies in serum from 7622 individuals who consented to the PROMISE screening study between Feb 26, 2019, and Nov 4, 2021, and the Mass General Brigham Biobank (MGBB) between July 28, 2010, and July 1, 2021. M-protein concentrations at the monoclonal gammopathy of indeterminate potential (MGIP) level were confirmed by liquid chromatography mass spectrometry testing. 6305 (83%; 2211 from PROMISE, 4094 from MGBB) of 7622 participants in the cohorts were at high risk for developing a monoclonal gammopathy on the basis of Black race or a family history of haematological malignancies and fell within the eligible high-risk age range (30 years or older for PROMISE cohort and 18 years or older for MGBB cohort); those over 18 years were also eligible if they had two or more family members with a blood cancer (PROMISE cohort). Participants with a plasma cell malignancy diagnosed before screening were excluded. Longitudinal clinical data were available for MGBB participants with a median follow-up time from serum sample screening of 4·5 years (IQR 2·4-6·7). The PROMISE study is registered with ClinicalTrials.gov, NCT03689595.The median age at time of screening was 56·0 years (IQR 46·8-64·1). 5013 (66%) of 7622 participants were female, 2570 (34%) male, and 39 (1%) unknown. 2439 (32%) self-identified as Black, 4986 (65%) as White, 119 (2%) as other, and 78 (1%) unknown. Using serum protein electrophoresis with immunofixation electrophoresis, the MGUS prevalence was 6% (101 of 1714) in high-risk individuals aged 50 years or older. Using mass spectrometry, we observed a total prevalence of monoclonal gammopathies of 43% (1788 of 4207) in this group. We termed monoclonal gammopathies below the clinical immunofixation electrophoresis detection level (0·2 g/L) MGIPs, to differentiate them from those with higher concentrations, termed mass-spectrometry MGUS, which had a 13% (592 of 4207) prevalence by mass spectrometry in high-risk individuals aged 50 years or older. MGIP was predominantly of immunoglobulin M isotype, and its prevalence increased with age (19% [488 of 2564] for individuals aged50 years, 29% [1464 of 5058] for those aged ≥50 years, and 37% [347 of 946] for those aged ≥70 years). Mass-spectrometry MGUS prevalence increased with age (5% [127 of 2564] for individuals aged50 years, 13% [678 of 5058] for those aged ≥50 years, and 18% [173 of 946] for those aged ≥70 years) and was higher in men (314 [12%] of 2570) compared with women (485 [10%] 5013; p=0·0002), whereas MGIP prevalence did not differ significantly by gender. In those aged 50 years or older, the prevalence of mass spectrometry was significantly higher in Black participants (224 [17%] of 1356) compared with the controls (p=0·0012) but not in those with family history (368 [13%] of 2851) compared with the controls (p=0·1008). Screen-detected monoclonal gammopathies correlated with increased all-cause mortality in MGBB participants (hazard ratio 1·55, 95% CI 1·16-2·08; p=0·0035). All monoclonal gammopathies were associated with an increased likelihood of comorbidities, including myocardial infarction (odds ratio 1·60, 95% CI 1·26-2·02; p=0·00016 for MGIP-high and 1·39, 1·07-1·80; p=0·015 for mass-spectrometry MGUS).We detected a high prevalence of monoclonal gammopathies, including age-associated MGIP, and made more precise estimates of mass-spectrometry MGUS compared with conventional gel-based methods. The use of mass spectrometry also highlighted the potential hidden clinical significance of MGIP. Our study suggests the association of monoclonal gammopathies with a variety of clinical phenotypes and decreased overall survival.Stand Up To Cancer Dream Team, the Multiple Myeloma Research Foundation, and National Institutes of Health.

Patients with smoldering multiple myeloma (SMM) are observed until progression, but early treatment may improve outcomes. We conducted a phase II trial of elotuzumab, lenalidomide, and dexamethasone (EloLenDex) in patients with high-risk SMM and performed single-cell RNA and T cell receptor (TCR) sequencing on 149 bone marrow (BM) and peripheral blood (PB) samples from patients and healthy donors (HDs). We find that early treatment with EloLenDex is safe and effective and provide a comprehensive characterization of alterations in immune cell composition and TCR repertoire diversity in patients. We show that the similarity of a patient's immune cell composition to that of HDs may have prognostic relevance at diagnosis and after treatment and that the abundance of granzyme K (GZMK)

Smoldering multiple myeloma (SMM) is a precursor condition of multiple myeloma (MM) with significant heterogeneity in disease progression. Existing clinical models of progression risk do not fully capture this heterogeneity. Here we integrate 42 genetic alterations from 214 SMM patients using unsupervised binary matrix factorization (BMF) clustering and identify six distinct genetic subtypes. These subtypes are differentially associated with established MM-related RNA signatures, oncogenic and immune transcriptional profiles, and evolving clinical biomarkers. Three genetic subtypes are associated with increased risk of progression to active MM in both the primary and validation cohorts, indicating they can be used to better predict high and low-risk patients within the currently used clinical risk stratification models.

Background Patients with Smoldering Multiple Myeloma (SMM) are typically observed until progression, but early treatment of high-risk patients may improve outcomes. Clinical and genomic biomarkers can be used to identify SMM patients at high risk of progression, however parallel profiling of the tumor immune microenvironment (TIME) may further improve prediction models. Methods Here, we performed single-cell RNA-sequencing on CD138- immune cells from 40 samples of 14 patients enrolled in a Phase II trial of Elotuzumab, Lenalidomide, and Dexamethasone, in patients with high-risk SMM (E-PRISM) to develop biomarkers for optimal patient selection and monitoring of response to treatment. Specifically, we profiled 33 bone marrow (BM) samples collected at baseline (n=11), cycle 9, Day 1 (C9D1, n=13) and EOT (n=9), and 7 peripheral blood mononuclear cell (PBMC) samples collected at baseline (n=4) and C9D1 (n=3). Results We found that higher abundance of mature B-cells, Th17 cells and GZMK+ T and NK cells and lower abundance of hematopoietic progenitor cells and plasmacytoid dendritic cells are associated with significantly longer progression-free survival (PFS) in SMM patients under treatment. This signal can be summarized by how normal-like the patients’ immune composition is at baseline, whereby patients whose immune composition is normal-like have significantly shorter PFS (p=0.031). This model suggests that at least some of the compositional changes observed in disease reflect the immune system’s capacity to react successfully to the immune challenge posed by the tumor, which we termed immune reactivity. Baseline immune reactivity may help to identify patients who will benefit the most from early treatment. Furthermore, we found that the expansion of tissue-resident NK cells and exhausted GZMK+ CD8+ T-cells at C9D1 of treatment is associated with significantly shorter PFS (p=0.039), suggesting that these immune biomarkers may help to monitor response to immunotherapy. Lastly, we found that patients would be classified the same way in terms of our immune biomarkers, had we assayed their peripheral blood instead of their bone marrow, suggesting that minimally invasive immune profiling for prognostication and monitoring may be feasible. Conclusion We used single-cell RNA-sequencing to profile the immune microenvironment of patients with high-risk SMM in a Phase II trial of Elotuzumab, Lenalidomide and Dexamethasone and developed immune biomarkers of response to treatment. Our study may usher in a next generation of clinical assays that assess both tumor biology and immune state, as well as common clinical biomarkers, in the marrow or blood, to accurately predict who may benefit from early treatment, monitor response and improve patient outcomes.

TO THE EDITOR: Waldenstrom macroglobulinemia (WM) is a rare lymphoplasmacytic lymphoma associated with immunoglobulin M monoclonal gammopathy.[1][1] The majority of patients carry the L265P mutation in MYD88,[2][2] whereas 40% of patients carry mutations in CXCR4.[3][3] Mutation status has an

In the past decades, considerable progress has been made in our understanding and treatment of multiple myeloma. Several challenges remain including our abilities to longitudinally image tumor responses to treatment, to combine various therapeutic agents with different mechanisms of action but with overlapping toxicities, and to efficiently harness the power of the immune system to augment remission and/or to induce permanent cures. Nanomedicine may help to address many of these outstanding issues, affording novel diagnostic capabilities and offering disruptive technologies that promise to revolutionize treatment. Here, we review recent developments and the future of nanomedicine for multiple myeloma, highlighting new considerations in nanoparticle designs that may help to augment active targeting, to facilitate longitudinal imaging, and to improve drug delivery.

Background Pregnancy represents a unique challenge for the maternal-fetal immune interface, requiring a balance between immunosuppression, which is essential for the maintenance of a semiallogeneic fetus, and proinflammatory host defense to protect the maternal-fetal interface from invading organisms. Adaptation to repeated inflammatory stimuli (endotoxin tolerance) may be critical in preventing inflammation-induced preterm birth caused by exaggerated maternal inflammatory responses to mild or moderate infections that are common during pregnancy. However, the exact mechanisms contributing to the maintenance of tolerance to repeated infections are not completely understood. MicroRNAs play important roles in pregnancy with several microRNAs implicated in gestational tissue function and in pathologic pregnancy conditions. MicroRNA-519c, a member of the chromosome 19 microRNA cluster, is a human-specific microRNA mainly expressed in the placenta. However, its role in pregnancy is largely unknown. Objective This study aimed to explore the role of “endotoxin tolerance” failure in the pathogenesis of an exaggerated inflammatory response often seen in inflammation-mediated preterm birth. In this study, we investigated the role of microRNA-519c, a placenta-specific microRNA, as a key regulator of endotoxin tolerance at the maternal-fetal interface. Study Design Using a placental explant culture system, samples from term and second-trimester placentas were treated with lipopolysaccharide. After 24 hours, the conditioned media were collected for analysis, and the placental explants were re-exposed to repeated doses of lipopolysaccharide for 3 days. The supernatant was analyzed for inflammatory markers, the presence of extracellular vesicles, and microRNAs. To study the possible mechanism of action of the microRNAs, we evaluated the phosphodiesterase 3B pathway involved in tumor necrosis factor alpha production using a microRNA mimic and phosphodiesterase 3B small interfering RNA transfection. Finally, we analyzed human placental samples from different gestational ages and from women affected by inflammation-associated pregnancies. Results Our data showed that repeated exposure of the human placenta to endotoxin challenges induced a tolerant phenotype characterized by decreased tumor necrosis factor alpha and up-regulated interleukin-10 levels. This reaction was mediated by the placenta-specific microRNA-519c packaged within placental extracellular vesicles. Lipopolysaccharide treatment increased the extracellular vesicles that were positive for the exosome tetraspanin markers, namely CD9, CD63, and CD81, and secreted primarily by trophoblasts. Primary human trophoblast cells transfected with a microRNA-519c mimic decreased phosphodiesterase 3B, whereas a lack of phosphodiesterase 3B, achieved by small interfering RNA transfection, led to decreased tumor necrosis factor alpha production. These data support the hypothesis that the anti-inflammatory action of microRNA-519c was mediated by a down-regulation of the phosphodiesterase 3B pathway, leading to inhibition of tumor necrosis factor alpha production. Furthermore, human placentas from normal and inflammation-associated pregnancies demonstrated that a decreased placental microRNA-519c level was linked to infection-induced inflammatory pathologies during pregnancy. Conclusion We identified microRNA-519c, a human placenta-specific microRNA, as a novel regulator of immune adaptation associated with infection-induced preterm birth at the maternal-fetal interface. Our study serves as a basis for future experiments to explore the potential use of microRNA-519c as a biomarker for infection-induced preterm birth.

Simple Summary The updated 4th edition WHO classification of lymphoid malignancies released in 2016 contains pivotal new terminology and information that is important for radiologists to understand. In spite of these updates, some lymphoproliferative disorders included in this update have been rarely discussed in the radiology literature. Many of these disorders have distinct clinical and imaging features, overlapping with more common disorders, thus causing a delay in diagnosis and management. Early diagnosis of many of these disorders is key as many of these are potentially treatable because early intervention may be lifesaving. The purpose of this manuscript is to provide guidance for radiologists regarding certain rare variants of B-cell lymphoproliferative disorders, in terms of clinical, histologic, and imaging findings, as well as to incorporate the new and updated terminology of some disorders included within the 4th edition of the WHO classification of lymphoid neoplasm. Abstract Lymphoproliferative disorders (LPD) are conditions characterized by the uncontrolled proliferation of B or T-cell lines. They encompass a wide spectrum of abnormalities, which may be broadly classified as reactive processes or malignant diseases, such as lymphoma, based on their cellular clonality and clinical behavior. While some of these disorders are rare, they may be encountered sporadically in clinical practice, causing diagnostic dilemmas owing to overlap in their clinical and imaging features with more common disorders. The updated 4th edition WHO classification of lymphoid neoplasms was released in 2016 to incorporate the rapid clinical, pathological, molecular biology and cytogenetic advances of some of these disorders. Despite these updates, very little information is presented in the literature from the radiology perspective. The aim of this article is to familiarize radiologists and other physicians with certain rare variants of B-cell lymphoproliferative disorders with a focus on imaging features of these disorders, as well as to provide an overview of some important updates contained within the new WHO classification of lymphoid neoplasms.

Introduction: Multiple Myeloma (MM) is an incurable plasma cell malignancy commonly preceded by the asymptomatic stage smoldering multiple myeloma (SMM). MM is characterized with significant genomic heterogeneity of chromosomal gains and losses (CNVs), translocations, and point mutations (SNVs); alterations that are also observed in SMM patients. However, current SMM risk models rely solely on clinical markers and do not accurately capture progression risk. While incorporating some genomic biomarkers improves prediction, using all MM genomic features to comprehensively stratify patients may increase risk stratification precision in SMM. Methods: We obtained a total of 214 patient samples at SMM diagnosis. We performed whole-exome sequencing on 166 tumors; of these, RNA sequencing was performed on 100. Targeted capture was done on 48 additional tumors. Upon binarization of DNA features, we performed consensus non-negative matrix factorization to identify distinct molecular clusters. We then trained a random forest classifier on translocations, SNVs, and CNVs. The predicted clinical outcomes for the molecular subtypes were further validated in an independent SMM cohort of 74 patients. Results: We identified six genomic subtypes, four with hyperdiploidy (>48 chromosomes, HMC, HKR, HNT, HNF) and two with IgH translocations (FMD, CND) (Table 1). In multivariate analysis accounting for IMWG (20-2-20) clinical risk stages, high-risk (HMC, FMD, HKR) and intermediate-risk (HNT, HNF) genetic subtypes were independent predictors of progression (Hazards ratio [HR]: 3.8 and 5.5, P = 0.016 and 0.001, respectively). The low-risk, CND subtype harboring translocation (11;14) was enriched for the previously defined CD-2 MM signature defined by the B cell markers CD20 and CD79A (FDR = 0.003 ), showed upregulation of CCND1, E2F1, and E2F7 (FDR = 0.01, 0.0004, 0.08), and was enriched for G2M checkpoint, heme metabolism, and monocyte cell signature (FDR = 0.003, 0.003, 0.003, respectively). The FMD subtype with IgH translocations (4;14) and (14;16) was enriched for P53, mTORC1, unfolded protein signaling pathways and plasmacytoid dendritic cell signatures (FDR = 0.01, 0.005, 0.008, respectively). The HKR tumors were enriched for inflammatory cytokine signaling, MYC target genes, T regulatory cell signature, and the MM proliferative (PR) signatures (FDR = 0.02, 0.03, 0.007, 0.02, respectively). The APOBEC mutational signature was enriched in HMC and FMD tumors (P = 0.005), while there was no statistical difference across subtypes in the AID signature. The median follow-up for the primary cohort is 7.1 years. Median TTP for patients in HMC, FMD, and HKR was 3.8, 2.6, and 2.2 years, respectively; TTP for HNT and HNF was 4.3 and 5.2, respectively, while it was 11 years in CND patients (P = 0.007). Moreover, by analyzing the changes in MM clinical biomarkers over time, we found that patients from high-risk subgroups had higher odds of developing evolving hemoglobin and monoclonal protein levels over time (P = 0.01 and 0.002, respectively); Moreover, the absolute increase in M-protein was significantly higher in patients from the high-risk genetic subtypes at one, two, and five years from diagnosis (P = 0.001, 0.03, and 0,01, respectively). Applying the classifier to the external cohort replicated our findings where intermediate and high-risk genetic subgroups conferred increased risk of progression to MM in multivariate analysis after accounting for IMWG staging (HR: 5.5 and 9.8, P = 0.04 and 0.005, respectively). Interestingly, within the intermediate-risk clinical group in the primary cohort, patients in the high-risk genetic subgroups had increased risk of progression (HR: 5.2, 95% CI 1.5 - 17.3, P = 0.007). In the validation cohort, these patients also had an increased risk of progression to MM (HR: 6.7, 95% CI 1.2 - 38.3, P = 0.03), indicating that molecular classification improves the clinical risk-stratification models. Conclusion: We identified and validated in an independent dataset six SMM molecular subgroups with distinct DNA alterations, transcriptional profiles, dysregulated pathways, and risks of progression to active MM. Our results underscore the importance of molecular classification in addition to clinical evaluation in better identifying high-risk SMM patients. Moreover, these subgroups may be used to identify tumor vulnerabilities and target them with precision medicine efforts. Figure 1 Figure 1. Disclosures Bustoros: Janssen, Bristol Myers Squibb: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria. Casneuf: Janssen: Current Employment. Kastritis: Amgen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Walker: Bristol Myers Squibb: Research Funding; Sanofi: Speakers Bureau. Davies: Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Dimopoulos: Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria; Beigene: Honoraria; Janssen: Honoraria. Bergsagel: Genetech: Consultancy, Honoraria; Oncopeptides: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: human CRBN mouse; GSK: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Yong: BMS: Research Funding; Autolus: Research Funding; Takeda: Honoraria; Janssen: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; GSK: Honoraria; Amgen: Honoraria. Morgan: BMS: Membership on an entity's Board of Directors or advisory committees; Jansen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees. Getz: IBM, Pharmacyclics: Research Funding; Scorpion Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.

Background Multiple myeloma (MM) evolves from monoclonal gammopathy of undetermined significance (MGUS), a clinically detectable but asymptomatic premalignant phase seen in ~3% of the general population 50 years of age or older. The prevalence of MGUS has not been described in a population at high risk of developing MM, specifically Black/African American (AA) individuals or first-degree relatives of patients with hematologic malignancies (HM). In 2019, we launched the first nationwide US screening study for individuals at high risk of MM to help better identify what population would benefit most from screening and early intervention for precursor MM stages. We aim to assess the prevalence of MGUS in a population at high risk of MM and characterize clinical variables of individuals who screen positive. Here, we report interim screening data on the first 2,960 participants. Methods Individuals aged 40 or older with an additional MM risk factor are eligible to be screened in the PROMISE Study. High-risk individuals include Black/AAs and those with a first-degree relative diagnosed with a hematologic malignancy or a precursor condition to MM. Blood from all participants was analyzed via serum protein electrophoresis, immunofixation, and Optilite® to measure the serum free light chains (sFLC), IgG, IgA and IgM. Results were returned to all participants, and those who tested positive for a monoclonal gammopathy (MGUS/SMM) were referred to a hematologist for clinical follow-up and invited to periodically complete epidemiologic exposure and psychosocial questionaries, including a 4-item cancer worry questionnaire and the RAND 36-item Short Form Survey (SF-36). To investigate the use of the higher-sensitivity matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) with the Optilite® IgG, IgA, IgM and sFLC results as a screening test for all participants, we rescreened 1,092 samples from PROMISE. The Binding Site Group proprietary software was used for the analysis of the combined MS/Optilite® results, allowing for the detection and quantification of M-protein. Heavy-Chain MGUS (HC-MGUS) was defined by the presence of one or more paired heavy and light chain monoclonal peaks detected by MS. Pairing was based on mass to charge ratio of identified peaks. To enrich the PROMISE cohort with Black/AA individuals, we identified and screened 1,868 Black/AA additional individuals from the Mass General Brigham (MGB) Biobank who met the PROMISE enrollment criteria. Screening was performed by MS/Optilite®, and results have not been returned to participants. Results We screened 2,960 participants with the combined MS/Optilite® approach. We report here the prevalence of HC-MGUS and plan on presenting the estimated rate of light chain MGUS in our cohort, at the meeting. We detected HC-MGUS in 9.6% (95% CI: 8.6-11%) of our cohort, with a prevalence of 10% (95% CI: 8.3-12%) in the PROMISE cohort and 9.4% (95% CI: 8.1-11%) in the MGB cohort (Table 1 and Figure 1). HC-MGUS prevalence increased with age in high-risk individuals from 4.9% (CI: 3.3-6.9%) for participants aged 40-49 to 13% (CI: 10-17%) in the 70-79 range (P < 1.2E-5). Among monoclonal HC-MGUS, we found 65% IgG, 18% IgM, and 18% IgA. M-spike was quantified in 97% of samples. Median M-spike concentration was, 0.058g/dL (max. 2.6g/dL) for IgG, 0.0043g/dL (max. 0.6g/dL) for IgM, and 0.067g/dL (max. 0.8g/dL) for IgA. In the Promise cohort, no significant change in cancer worry was observed across the pre- and post-screening interval among participants who screened positive (P = 0.52). Health-related quality of life, as measured by the SF-36, was not significantly different in screen-positive vs. screen-negative individuals for any of the eight subscales (all P > 0.20). Conclusions We present the largest dataset on monoclonal gammopathy prevalence and screening in individuals at high risk for MM, and more specifically the largest cohort of Black/AA, using a novel high-sensitivity testing approach. Our results confirm that older adults who are Black/AA or have a first-degree relative with an HM have a high prevalence MGUS and may benefit from precision screening approaches to allow for early detection and clinical intervention. Preliminary data on cancer worry and quality of life indicates that the psychosocial burden of screening in this population is likely minimal. Figure 1 Figure 1. Disclosures Sakrikar: The Binding Site: Current Employment. Krause: The Binding Site: Current Employment. Barnidge: The Binding Site: Current Employment. Bustoros: Takeda: Consultancy, Honoraria; Janssen, Bristol Myers Squibb: Honoraria, Speakers Bureau. Perkins: The Binding Site: Current Employment. Harding: The Binding Site: Current Employment, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Kapoor: Ichnos Sciences: Research Funding; Amgen: Research Funding; Pharmacyclics: Consultancy; Takeda: Research Funding; Sanofi: Consultancy; Regeneron Pharmaceuticals: Research Funding; AbbVie: Research Funding; BeiGene: Consultancy; Sanofi: Research Funding; Karyopharm: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy. Mo: Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy; Eli Lilly: Consultancy; Janssen: Honoraria; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees. Murray: The Binding Site: Patents & Royalties: Potential Royalties for use of mass spectrometry in M-protein detection. Getz: Scorpion Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; IBM, Pharmacyclics: Research Funding. Marinac: JBF Legal: Consultancy; GRAIL Inc: Research Funding. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.

Background Patients with Smoldering Multiple Myeloma (SMM) are typically observed until progression to overt Multiple Myeloma (MM), but early treatment of high-risk patients may improve outcomes. Clinical and genomic biomarkers can help to identify SMM patients at high risk of progression, but whether parallel profiling of the tumor immune microenvironment can further improve our models remains to be determined. Methods We performed single-cell RNA sequencing on CD138- immune cells from 40 samples of 14 patients with high-risk SMM enrolled in a Phase II trial of Elotuzumab, Lenalidomide, and Dexamethasone (NCT02279394), to develop biomarkers for optimal patient selection and monitoring of response to treatment. This study was approved by the Dana-Farber Cancer Institute's Institutional Review Board (#14-338). Specifically, we used the Chromium Single Cell 3' Gene Expression system by 10X Genomics to profile 33 magnetically sorted (Miltenyi Biotec) CD138- bone marrow (BM) samples collected at baseline (n=11), cycle 9 day 1 (C9D1, n=13), and end of treatment (EOT, n=9), and 7 peripheral blood mononuclear cell (PBMC) samples collected at baseline (n=4) and C9D1 (n=3). We integrated this data with our cohort of non-trial patients with Monoclonal Gammopathy of Undetermined Significance (n=5), low-risk SMM (n=3), high-risk SMM (n=8), newly diagnosed MM (n=9) and healthy donors (n=10), reaching a total of 75 samples. Results We found that higher abundance of mature B-cells, Th17, and Granzyme K (GZMK)+ T-cells, as well as gene expression signatures marked by type 17 genes and GZMK, are associated with significantly longer progression-free survival (PFS) in SMM patients under treatment. Although immunoparesis is a significant predictor of PFS in our cohort and could thus be confounding our B-cell signal, we showed that immunoparesis is not associated with lower number of B-cells in the BM and is instead associated with the upregulation of transcription factor Kruppel-like Factor 2 (KLF2, q=2e-05), which we hypothesize may oppose differentiation into antibody-secreting plasma cells. We found that these differences in abundance can be summarized by how normal-like the patients' immune composition is at baseline, whereby patients whose immune composition is not normal-like have significantly longer PFS (p=0.031). This model suggests that at least some of the compositional changes observed in disease may reflect the immune system's capacity to react successfully to the immune challenge posed by the tumor, which we termed 'immune reactivity'. Baseline immune reactivity may help to identify patients who will benefit the most from early treatment. Furthermore, we found that the expansion of tissue-resident NK cells and exhausted GZMK+ CD8+ T-cells at C9D1 of treatment, as well as higher levels of a gene expression signature marked by amphiregulin (AREG), are associated with significantly shorter PFS (p=0.039). These biomarkers may improve monitoring of response to immunotherapy, which may not be fully explained by residual tumor burden alone. Lastly, patients whose immune profile was normal-like at EOT (Post-therapy Immune Normalization, PIN), potentially signifying the resolution of the immune challenge, had significantly longer biochemical PFS (p=0.04). Assessment of PIN at EOT may improve stratification of patients with minimal residual disease. Importantly, we found that biomarker status could be assessed in both the patients' peripheral blood and their BM, suggesting that minimally invasive immune profiling for prognostication and monitoring may be feasible. Conclusions Our study has nominated novel immune biomarkers for optimal patient selection and assessment of response to immunotherapy and uncovered a previously unappreciated mechanism of B-cell immunosuppression in MM, which could lead to the development of novel therapeutics. Our findings may usher in a next generation of clinical assays that assess both tumor biology and immune state, as well as common clinical biomarkers, in the marrow or blood, to accurately predict who may benefit from early treatment, monitor response to immunotherapy, and improve patient outcomes. Disclosures Dutta: Menarini Silicon Biosystems: Consultancy. Haradhvala: Constellation Pharmaceuticals a MorphoSys Company: Consultancy. Zavidij: Constellation Pharmaceuticals: Current Employment. Bustoros: Janssen, Bristol Myers Squibb: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria. Rosenblatt: Attivare: Consultancy; Imaging Endpoints: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Parexel: Consultancy; Wolters Kluwer Health Inc: Consultancy, Patents & Royalties. Zonder: Caelum Biosciences: Consultancy; Intellia: Consultancy; Alnylam: Consultancy; Regeneron: Consultancy; Janssen: Consultancy; BMS: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy. Bhutani: Janssen, MedImmune, Takeda, Celgene, BMS, Cerecor, Celularity: Research Funding; Sanofi: Consultancy; Amgen, BMS, Takeda: Speakers Bureau. Usmani: Array BioPharma: Consultancy, Research Funding; Abbvie: Consultancy; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; GSK: Consultancy, Research Funding; EdoPharma: Consultancy; Janssen: Consultancy, Research Funding, Speakers Bureau; Sanofi: Consultancy, Research Funding, Speakers Bureau; Merck: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; SkylineDX: Consultancy, Research Funding; Takeda: Consultancy, Research Funding, Speakers Bureau; Janssen Oncology: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding; Amgen: Consultancy, Research Funding, Speakers Bureau. Yee: Bristol Myers Squibb: Consultancy; Oncopeptides: Consultancy; Amgen: Consultancy; Janssen: Consultancy; GSK: Consultancy; Adaptive: Consultancy; Sanofi: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy. Jakubowiak: Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Manier: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene - Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Research Funding; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Nadeem: GSK: Consultancy; Adaptive: Consultancy; Bristol Myer Squibb: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy. Richardson: GlaxoSmithKline: Consultancy; Takeda: Consultancy, Research Funding; AbbVie: Consultancy; AstraZeneca: Consultancy; Celgene/BMS: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding; Janssen: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy, Research Funding; Regeneron: Consultancy; Secura Bio: Consultancy; Protocol Intelligence: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding. Badros: J&J: Research Funding; BMS: Research Funding; Janssen: Research Funding; GlaxoSmithKline: Research Funding. Mateos: Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird bio: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria; Oncopeptides: Honoraria; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sea-Gen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene - Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria. Getz: IBM, Pharmacyclics: Research Funding; Scorpion Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees. Ghobrial: AbbVie, Adaptive, Aptitude Health, BMS, Cellectar, Curio Science, Genetch, Janssen, Janssen Central American and Caribbean, Karyopharm, Medscape, Oncopeptides, Sanofi, Takeda, The Binding Site, GNS, GSK: Consultancy.

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by notable interpatient heterogeneity. There have been important advances in therapy and overall survival, but some patients with high-risk features still have poor survival rates. Therefore, accurate identification of this subset of patients has been integral to improvement of patient outcome. During the last few years, cytogenetics, gene expression profiling, MRI and PET/CT, as well as serum free light chain assays have been used as accurate biomarkers to better characterize the diverse course and outcome of the disease. With the recent advances of massive parallel sequencing techniques, the development of new models that better stratify high-risk groups are beginning to be developed. The use of multiparameter flow cytometry and next-generation sequencing have paved the way for assessment of minimal residual disease and better prognostication of post-therapeutic outcomes. Circulating tumor cells and circulating tumor DNA are promising potential biomarkers that demonstrate the spatial and temporal heterogeneity of MM. Finally, more prognostic markers are being developed that are specific to immunotherapeutic agents. In this review, we discuss these traditional and novel biomarkers that have been developed for MM and also those that can predict disease progression from precursor stages. Together, these biomarkers will help improve our understanding of the intrapatient and interpatient variabilities and help develop precision medicine for patients with high-risk MM.

Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by clonal proliferation of plasma cells and a heterogenous genomic landscape. Copy number and structural changes due to chromosomal instability (CIN) are common features of MM. In this review, we describe how primary and secondary genetic events caused by CIN can contribute to increased instability across the genome of malignant plasma cells; with a focus on specific driver genomic events, and how they interfere with cell-cycle checkpoints, to prompt accelerated proliferation. We also provide insight into other forms of CIN, such as chromothripsis and chromoplexy. We evaluate how the tumor microenvironment can contribute to a further increase in chromosomal instability in myeloma cells. Lastly, we highlight the role of certain mutational signatures in leading to high mutation rate and genome instability in certain MM patients. We suggest that assessing CIN in MM and its precursors states may help improve predicting the risk of progression to symptomatic disease and relapse and identifying future therapeutic targets.

BACKGROUND Waldenström macroglobulinemia (WM) is preceded by asymptomatic WM (AWM), for which the risk of progression to overt disease is not well defined. METHODS We studied 439 patients with AWM, who were diagnosed and observed at Dana-Farber Cancer Institute between 1992 and 2014. RESULTS During the 23-year study period, with a median follow-up of 7.8 years, 317 patients progressed to symptomatic WM (72%). Immunoglobulin M 4,500 mg/dL or greater, bone marrow lymphoplasmacytic infiltration 70% or greater, β2-microglobulin 4.0 mg/dL or greater, and albumin 3.5 g/dL or less were all identified as independent predictors of disease progression. To assess progression risk in patients with AWM, we trained and cross-validated a proportional hazards model using bone marrow infiltration, immunoglobulin M, albumin, and beta-2 microglobulin values as continuous measures. The model divided the cohort into three distinct risk groups: a high-risk group with a median time to progression (TTP) of 1.8 years, an intermediate-risk group with a median TTP of 4.8 years, and a low-risk group with a median TTP of 9.3 years. We validated this model in two external cohorts, demonstrating robustness and generalizability. For clinical applicability, we made the model available as a Web page application ( www.awmrisk.com ). By combining two cohorts, we were powered to identify wild type MYD88 as an independent predictor of progression (hazard ratio, 2.7). CONCLUSION This classification system is positioned to inform patient monitoring and care and, for the first time to our knowledge, to identify patients with high-risk AWM who may need closer follow-up or benefit from early intervention.

Background: Multiple Myeloma (MM) is an incurable plasma cell malignancy with significant genomic heterogeneity. It is usually preceded by the asymptomatic stage known as smoldering multiple myeloma (SMM). SMM patients have a 10% annual risk of progression to MM. Genomic alterations that are observed in SMM patients include chromosomal gains and losses, translocations, and point mutations. However, current SMM risk models rely solely on clinical markers that do not accurately capture the progression risk. While incorporating some genomic biomarkers improves prediction, using all MM genomic features to comprehensively stratify patients may increase the precision of risk models. Methods: We obtained a total of 214 patients' samples at SMM diagnosis in the US and Europe. We performed whole exome sequencing on 166 tumors; of these, RNA sequencing was performed on 100. Targeted capture with a MM gene panel was done on an additional 48 tumors. We identified subgroups using binarized DNA features and performing consensus binary non-negative matrix factorization. Results: We identified six clusters (C1-C6) with the following features: four with a hyperdiploidy (HD) (>48 chromosomes) and two with IgH translocations. These subgroups have unique transcriptomic profiles overlapping with known MM signatures and biological pathways. One of the clusters harboring translocation (11;14), which we call C4-CCND1, was enriched with the previously defined CD-2 MM signature that uniquely expresses B cell markers CD20 and CD79A; shows upregulation of CCND1 and E2F7; and is enriched with pathways like DNA replication, heme metabolism, and NFkB signaling. The C3-MS_MF cluster with the IgH translocations (4;14) and (14;16) shows downregulation of ribosomal genes, TRAF2, and DUSP2. The MYC oncogene was highly expressed in the four HD clusters: C1-HD_NRAS, C2-HD_MAFB, C5-HD_KRAS, and C6-HD_1q (BH-P = 0.037). The clusters also showed different outcomes in terms of time to progression (TTP) to active MM (P = 0.005). Median TTP for patients in C2-HD_MAFB, C3-MS_MF, and C5-HD_KRAS was 3.7, 2.6, and 2.2 years, respectively; TTP for C1-HD_NRAS, C4-CCND1, and C6-HD_1q was 4.3, 11, and not reached, respectively. In multivariate analysis, C2-HD_MAFB, C3-MS_MF, and C5-HD_KRAS were independent predictors of progression after accounting for the clinical risk stage. Moreover, the odds of having evolving hemoglobin and monoclonal protein levels in these three clusters were 3.5 and 12.3 times higher than the other clusters, respectively (P = 0.01 and 0.002). Conclusion: We identified six distinct SMM molecular groups with corresponding transcription profiles and dysregulated pathways. These groups have different progression risks to active MM, with three groups being independent predictors of progression. Our results underscore the importance of molecular classification in MM to better understand and target various tumor vulnerabilities. Citation Format: Shankara Anand, Mark Bustoros, François Aguet, Romanos Sklavenitis-Pistofidis, Robert Redd, Benny Zhitomirsky, Andrew J. Dunford, Yu-Tzu Tai, Selina J. Chavda, Cody Boehner, Carl J. Neuse, Tineke Casneuf, Lorenzo Trippa, Chip Stewart, Kwee Yong, Irene Ghobrial, Gad Getz. Genomic profiling of smoldering multiple myeloma classifies distinct molecular groups [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2240.

High-grade glioma (HGG), a deadly primary brain malignancy, manifests radioresistance mediated by cell-intrinsic and microenvironmental mechanisms. High levels of the cytokine transforming growth factor-β (TGF-β) in HGG promote radioresistance by enforcing an effective DNA damage response and supporting glioma stem cell self-renewal. Our analysis of HGG TCGA data and immunohistochemical staining of phosphorylated Smad2, which is the main transducer of canonical TGF-β signaling, indicated variable levels of TGF-β pathway activation across HGG tumors. These data suggest that evaluating the putative benefit of inhibiting TGF-β during radiotherapy requires personalized screening. Thus, we used explant cultures of seven HGG specimens as a rapid, patient-specific ex vivo platform to test the hypothesis that LY364947, a small molecule inhibitor of the TGF-β type I receptor, acts as a radiosensitizer in HGG. Immunofluorescence detection and image analysis of γ-H2AX foci, a marker of cellular recognition of radiation-induced DNA damage, and Sox2, a stem cell marker that increases post-radiation, indicated that LY364947 blocked these radiation responses in five of seven specimens. Collectively, our findings suggest that TGF-β signaling increases radioresistance in most, but not all, HGGs. We propose that short-term culture of HGG explants provides a flexible and rapid platform for screening context-dependent efficacy of radiosensitizing agents in patient-specific fashion. This time- and cost-effective approach could be used to personalize treatment plans in HGG patients.

Multiple myeloma (MM) is an incurable malignancy of plasma cells and the second most common adult hematologic malignancy in the USA, with an annual incidence of 6.3 new cases per 100,000 individuals. MM usually progresses from asymptomatic precursor stages, known as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). MGUS can progress into MM at a rate of 1% per year, while SMM carries a higher chance of progression of approximately 10% per year. The incidence of MGUS is about 3% of the general population aged 50 years. African Americans (AA) have a 3-fold increased prevalence of MGUS and tend to have worse MM outcomes compared to Caucasians. Some patients rapidly progress from MGUS/SMM to MM, while others remain indolent with minimal progression over their lifetime due to the significant inter-patient heterogeneity. Genomic studies are increasingly delineating the complexity of MM genomic landscape. MM genomic alterations are characterized by multiple chromosomal gains or losses, structural variations, and mutations. The full suite of MM driver events is present in most cases in the SMM stage. The most common driver events in MM are copy number alterations followed by mutations and IgH translocations; however, recent whole-genome sequencing efforts identified more structural events such as MYC translocations, chromothripsis, and chrompolexy. Recently, single-cell RNA sequencing (ScRNAseq) studies provided a better understanding of both the tumor and immune cell architecture in the bone marrow niche. Tumor cells’ ScRNAseq showed that SMM patients are indistinguishable, at the molecular level, from those with active MM and highlighted an inter and intrapatient heterogeneity. Moreover, ScRNA seq of the immune microenvironment revealed that altered immune repertoire starts as early as MGUS and evolves through SMM and MM. Few studies identified potential differences in the molecular profile between AA and Caucasian patients. However, more extensive prospective studies are needed to confirm and identify possible variations among different races and ensure better representation of minorities in MM research. Citation Format: Mark Bustoros. Advances in genomic characterization of multiple myeloma and its precursor states [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr IA42.

Direct-to-Patient (DTP) Multiple Myeloma (MM) research studies have been launched recently, including PCROWD (NCT02269592), PROMISE (NCT03689595) and the MMRF CureCloud Research Initiative (NCT03657251), aimed at enrolling thousands of individuals from whom comprehensive molecular and immune analyses will be generated from blood specimens and the resulting data aggregated with the correlating clinical information. To support the molecular characterization of liquid biopsies for such DTP efforts, a set of myeloma-specific liquid biopsy approaches were developed. First, a hybrid selection panel was developed that detects somatic variants present in a patient's circulating-free DNA (cfDNA) in 70 commonly altered MM and Clonal Hematopoiesis of Indeterminate Potential (CHIP) genes. For this MM 70-Gene cfDNA Assay, samples are received as blood in a StreckTM tube designed for stabilization of cfDNA and DNA is extracted from buffy coat using magnetic bead-based chemistry. Deep coverage sequencing (80,000x depth) is performed and duplex BAM files generated with UMI alignment and error correction allowing for sensitive detection of clinically relevant variants. Technical validation data on healthy donor cfDNA mixes was generated using samples with a range of cfDNA inputs. This data determined that the assay is capable of achieving >90% sensitivity for detecting somatic events present at 1% variant allele frequency with a specificity of Because one the aims of this effort is to return results to treating physicians, a clinical-grade (CLIA) pipeline was established. For that CLIA pipeline, the variants reported are a subset of all the events detected by the MM 70-Gene Assay. The events detected in the assay are reviewed by experienced molecular pathologists at the Dana Farber Cancer Institute (DFCI) who have developed a customized reporting process. These reports utilize an internally-developed knowledgebase of variant/gene annotations that leverages the DFCI expertise in hematologic malignancies and myeloma specifically. The reports are then provided back through providers to the patient via the CureCloud system for their use in clinical care and trial identification. In order to complement the MM-70 Gene panel with copy number and translocation information, we have been exploring Circulating Multiple Myeloma Cells (CMMCs). Our current approach involves automated capture of CMMCs using ferrofluids coated with MM-selective and discriminating antibodies to immunomagnetically enrich circulating plasma cells. The highly enriched CMMCs fractions generated in such a fashion are then submitted for molecular characterization. At the submission date of this abstract, 163 patients have been fully enrolled into CureCloud from which results will be presented. In summary, we have developed a robust and very sensitive clinical-grade next-gen liquid biopsy sequencing platform allowing for minimally invasive monitoring of MM disease genomics that can be used to complement other more classical approaches and to help support our Direct-To-Patient Initiatives. Especially in this post-COVID19 era, such liquid biopsy-based approaches that avoid clinic visits for the patients and can be performed through at-home mobile phlebotomy are emerging as important new options. Disclosures Kim: LabCorp: Consultancy; Quanterix, Inc: Consultancy; PapGene, Inc: Consultancy. Ghobrial:AbbVie: Consultancy; GNS Healthcare: Consultancy; GlaxoSmithKline: Consultancy; Genentech: Consultancy; Noxxon Pharma: Consultancy; Novartis: Consultancy; Adaptive Biotechnologies: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Cellectar: Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria.

Pregnancy in essential thrombocythemia (ET) is associated with increased risk of obstetric complications. We retrospectively evaluated risk factors in 121 pregnancies in 52 ET women seen at 3 affiliate hospitals. Univariable and multivariable analyses were performed at the α = 0.10 level. Cell counts were characterized throughout pregnancy and correlated with outcomes using logistic modeling. The overall live birth rate was 69 %. 48.7 % of all women experienced a pregnancy complication, the most common being spontaneous abortion, which occurred in 26 % of all pregnancies. Maternal thrombosis and hemorrhage rates were 2.5 % and 5.8 %. On multivariable analysis, aspirin use (OR 0.29, p = 0.014, 90 % CI 0.118–0.658) and history of prior pregnancy loss (OR 3.86, p = 0.011, CI 1.49–9.15) were associated with decreased and increased pregnancy complications, respectively. A Markov model was used to analyze the probability of a future pregnancy complication based on initial pregnancy outcome. An ET woman who suffers a pregnancy complication has a 0.594 probability of a subsequent pregnancy complication, compared to a 0.367 probability if she didn’t suffer a complication. However, despite this elevated risk, overall prognosis is good, with a >50 % probability of a successful pregnancy by the third attempt. Platelet counts decreased by 43 % in ET during pregnancy, with nadir at delivery and prompt recovery in the postpartum period. Women with larger declines in gestational platelet counts were less likely to suffer complications (p = 0.083). Our study provides important guidance to physicians treating ET women during pregnancy, including counseling information regarding risk assessment and expected trajectory of platelet levels.

Direct-to-patient (DTP) multiple myeloma (MM) research studies have been launched recently, including PCROWD (NCT02269592), PROMISE (NCT03689595), and the MMRF CureCloud Research Initiative (NCT03657251), aimed at enrolling thousands of individuals from whom comprehensive molecular and immune analyses will be generated from blood specimens and the resulting data aggregated with the correlating clinical information. To support the molecular characterization of liquid biopsies for such DTP efforts, a myeloma-specific hybrid selection panel was developed that captures 70 commonly altered genes. The assay detects somatic point mutations and indels present in a patient’s circulating-free DNA (cfDNA). For this MM 70-Gene cfDNA Assay, samples are received as blood in a Streck’s tube and DNA is extracted from buffy coat using magnetic bead-based chemistry. Coverage sequencing (80,000x depth) is performed and duplex BAM files are generated with UMI alignment and de-duplication. As will be presented, MM blood specimens present a unique challenge as circulating MM cells are often present at significant levels in the buffy coat blood fraction used as the source of normal genomic DNA. The performance of the 70-Gene cfDNA Assay was thoroughly validated in order to establish the sensitivity, specificity, and reproducibility of the technical approach. First, the reference genomic DNA from unrelated healthy individuals was sequenced in replicate at deep coverage. Next, two cohorts were used, one from Dana-Farber and one from the MMRF CureCloud pilot. For both cohorts, tumor DNA samples from bone marrow aspirates (BMAs) with matched normal DNA from blood were sequenced on an orthogonal platform and compared to results from the MM 70-Gene Assay on cfDNA extracted from the same individuals. The yield of extracted cfDNA ranged from 6 ng to 80 ng, and about two third of cases yielded enough material to attempt sequencing, with failures coming mostly from individuals in remission. As will be presented, there was a very strong correlation between BMA and cfDNA and additional events could actually be detected in the blood that were not seen in the BMAs. Because this MM 70-Gene cfDNA Assay may potentially be used by treating physicians for management of care, a clinical-grade (CLIA) pipeline was established. For that CLIA pipeline, the variants reported are a subset of all the events detected by the MM 70-Gene Assay. The events detected in the assay are reviewed by a Genomic Tumor Board within the appropriate subset of territory predefined for reporting. The territory limitations are defined by the Genomic Tumor Board knowledgebase of actionable genomic territory available. In summary, we have developed a robust and very sensitive clinical-grade next-gen liquid biopsy sequencing platform allowing for less invasive monitoring of MM disease genomics that can be used to complement other more classical approaches and to help support direct-to-patient Initiatives. Citation Format: Mark W. Bustoros, Carrie Cibulskis, Teni Dowdell, Svetlana Gavrilov, Cody Boehner, Jennifer Yesil, Steven E. Labkoff, Shaadi Mehr, Jihye Park, Romanos Sklavenitis Pistofidis, Salomon Manier, Annette S. Kim, Keith L. Ligon, Niall Lennon, Viktor Adalsteinsson, Jane Wilkinson, Irene M. Ghobrial, Daniel Auclair. A novel clinical-grade liquid biopsy platform for multiple myeloma [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A38.

Background. Extraosseous Ewing’s sarcoma in the spinal epidural space is a rare malignancy, especially in adults.Case Presentation. A 40-year-old male presented with back pain and urinary hesitancy. MRI revealed a thoracic extradural mass with no osseous involvement. He underwent surgery for gross total resection of the mass, which was diagnosed as Ewing’s sarcoma. He was subsequently treated with chemoradiotherapy. He remains disease-free 1 year after surgery. Review of the literature indicated only 45 previously reported cases of spinal epidural extraosseous Ewing’s sarcoma in adults.Conclusions. Extraosseous Ewing’s sarcoma in the spinal epidural space is a rare clinical entity that should be included in the differential for spinal epidural masses. Its treatment is multidisciplinary but frequently requires surgical intervention due to compressive neurologic symptoms. Gross total resection appears to correlate with improved outcomes.

Introduction: Daratumumab (DARA) is an anti-CD38 monoclonal antibody that is approved for use in patients with newly diagnosed and relapsed multiple myeloma (MM). We hypothesized that early therapeutic intervention with DARA in patients with high-risk MGUS (HR-MGUS) or low-risk SMM (LR-SMM) would lead to eradication of the tumor clone by achieving deep responses, resulting in prevention of progression to MM. This is a single-arm, phase II study evaluating efficacy and safety of using DARA in patients with HR-MGUS and LR-SMM. Methods: Patients enrolled on this study met eligibility for either: 1) HR-MGUS defined as 1.65, M protein ≥ 1.5g/dL or non-IgG M protein or 2) LR-SMM with one of the following 3 criteria: M protein ≥3g/dL, ≥10% bone marrow plasma cells, SFLC ratio 8. DARA (16mg/kg) was administered intravenously on a weekly schedule for cycles 1-2, every other week cycles 3-6, and monthly during cycles 7-20. The primary objective of this study was to determine proportion of patients who are in VGPR or greater after 20 cycles of DARA. Secondary objectives included duration of response, safety, and rates of MRD negativity in VGPR or greater patients. Correlative studies included assessing changes in immune microenvironment, evaluating clonal heterogeneity using deep sequencing, and determining association of genomic aberrations correlating with either response to therapy or progression of disease. Results: A total of 31 patients were enrolled on this study from January 2018 to June 2019 with participation of five sites. The median age for all patients enrolled was 59 years (range 41 to 76), with 16 males (52%) and 15 females (48%). Majority of patients enrolled were classified as LR-SMM (n = 29; 94%) and the remaining 2 patients had HR-MGUS (6%). Twenty-eight patients have started treatment and are included in toxicity assessment and 15 patients have at least completed cycle 6 (range 1-19). Grade 3 toxicities were rare and only experienced in 2/28 patients including diarrhea (n =1) and flu like symptoms (n = 1). Most common toxicities of any grade included fatigue (n = 13/28, 46%), cough (n = 11/28, 39%), nasal congestion (n = 10/28, 36%), headache (n = 8/28, 29%), hypertension (n = 8/28, 29%), nausea (n = 8/28, 29%), and white blood cell decreased (n = 8/28, 29%). All patients remain on treatment and none have discontinued therapy due to toxicity. Best overall responses were CR (n = 1, 3%), VGPR (n = 3, 11%), PR (n = 9, 32%, 2 unconfirmed), MR (n = 10, 36%), SD (n = 5, 18%, 1 unconfirmed), PD (n = 0, 0%), and NE (n = 1, 4%). Minimal response or better was observed in 82% of patients (23/28) and PR or better was observed in 46% of patients (13/28). In the 15 patients who completed at least 6 cycles, response rates were as follows: MR or better 93% (14/15), PR or better 73% (11/15) and VGPR or better 20% (3/15). Median time to VGPR was 3.2 months. Median overall survival and progression-free survival have not been reached. Thus far, no patients have progressed to MM. Conclusion: DARA is very well tolerated among patients with HR-MGUS and LR-SMM. Responses are seen in majority of patients and there has been no observed progression to MM to date. Early therapeutic intervention in this precursor patient population appears promising. Disclosures Nadeem: Celgene: Honoraria; Janssen: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. Yee:Bristol-Myers Squibb: Consultancy, Research Funding; Karyopharm: Consultancy; Adaptive: Consultancy; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy. Zonder:Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Intellia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Alnylam: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees. Rosenblatt:Partner Tx: Other: Advisory Board; Dava Oncology: Other: Education; Celgene: Research Funding; BMS: Research Funding; Parexel: Consultancy; Merck: Other: Advisory Board; BMS: Other: Advisory Board ; Amgen: Other: Advisory Board; Imaging Endpoint: Consultancy. Bustoros, MD:Takeda: Honoraria. Prescott:Janssen: Equity Ownership. Castillo:Abbvie: Research Funding; Janssen: Consultancy, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Consultancy, Research Funding; Beigene: Consultancy, Research Funding. Munshi:Abbvie: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Oncopep: Consultancy; Takeda: Consultancy; Adaptive: Consultancy. Anderson:Sanofi-Aventis: Other: Advisory Board; Bristol-Myers Squibb: Other: Scientific Founder; Oncopep: Other: Scientific Founder; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Richardson:Amgen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding. Ghobrial:Janssen: Consultancy; Celgene: Consultancy; Takeda: Consultancy; Amgen: Consultancy; BMS: Consultancy; Sanofi: Consultancy. OffLabel Disclosure: Daratumumab has not been approved by the US Food and Drug Administration or any other regulatory agency worldwide for the uses under investigation.

BACKGROUND: Myeloproliferative neoplasms (MPNs) including essential thrombocythemia (ET) and polycythemia vera (PV) are commonly diagnosed in the sixth decade, but as many as 20% of patients are younger than 40. This introduces the possibility of pregnancy and need for specialized management. ET/PV patients have a higher risk of pregnancy complications, with a reported 68.5% live birth rate (LBR), and 1.8% and 2.4% risk of major thrombotic and bleeding events respectively. Risk factors for pregnancy complications are conflicting, and further contemporary studies are needed. METHODS: We retrospectively analyzed 130 pregnancies in 58 ET/PV women seen at 3 affiliate hospitals from 1995-2019. Patients were identified using ICD-9/10 codes in the electronic medical record. We analyzed 12 input variables as risk factors associated with first pregnancy complications after MPN diagnosis by univariate logistic regression (α=0.1, type I error rate; Table 1a). Variables with p RESULTS: The analysis included 53 ET patients and 5 PV patients. Driver mutation status for JAK2, CALR, or MPL was available in 79% of all patients: 60.3% were JAK2+ and 12.1% were CALR+. 2 patients were high-risk by International Prognostic Score of thrombosis (IPSET). Median maternal age was 34, median year of delivery was 2010, and median time between MPN diagnosis and index pregnancy was 3 years. There were no complications in 46% of pregnancies. The LBR was 70%. Aspirin (ASA) and interferon were used in 58.5% and 1.5% of pregnancies, respectively. In the pregnancies that resulted in live birth, postpartum low-molecular-weight heparin (LMWH) was used in 23.5% of cases. Antepartum LMWH was used in 6.9% of cases. PV patients were more likely to be treated with ASA (p=0.039) or postpartum LMWH (p=0.013) compared to ET patients. The most common complication was spontaneous abortion (SAB), defined as fetal loss On univariate analysis, only history of miscarriage prior to MPN diagnosis (13.2% of women) and ASA use during pregnancy were significantly associated with outcomes. On multivariate analysis, history of prior miscarriage remained statistically significant (OR 8.82, p=0.023), while ASA use during pregnancy trended toward improved outcomes (OR 0.33, p=0.12). All other variables were not significantly associated with pregnancy outcomes (Table 1a). Cell counts throughout pregnancy were available in 53 ET patients (Figure 1). There was a significant decline in platelets (p CONCLUSIONS: In this contemporary analysis of pregnancy outcomes in 130 ET/PV women, we demonstrate that overall prognosis is good, with a LBR of 70%. However, pregnant ET/PV patients remain at high risk, with SAB and complication rates of 24.6% and 54%, and maternal thrombosis and hemorrhage occurring in 2.3% and 6.9% of pregnancies. We show for the first time that prior miscarriage is a significant predictor of pregnancy complication in MPN patients (OR 8.82). Cell counts have never been systematically evaluated in MPN patients throughout pregnancy. We found that platelet counts decrease dramatically, often to normal, in ET. Platelet recovery occurs quickly in the postpartum period, with most patients returning to 75% of their baseline platelet count by one month postpartum. The observed 43% platelet nadir from starting counts to the day of delivery is greater than the expected 20% platelet decrease in the normal pregnant population. This decrease is unlikely to be explained by hemodilution, as the observed Hg decrease in ET patients approximates that seen in normal women. While we found no effect of JAK2 or CALR mutation status on pregnancy complications, it is possible that changes in allele burden influence platelet trends and outcomes. Measuring these changes in available women is the next step in our investigation. Disclosures Bustoros, MD: Takeda: Honoraria. Connell:Michael H. Flanagan Foundation: Membership on an entity's Board of Directors or advisory committees. Connors:Bristol Myer-Squibb: Consultancy, Other: Scientific Ad boards; Portola: Other: scientific ad boards; Abbott: Consultancy; Eli Lilly: Consultancy. Kuter:Argenx: Consultancy, Honoraria, Research Funding; Alnylam: Consultancy, Honoraria, Research Funding; UCB: Consultancy, Honoraria; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Agios: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Momenta: Consultancy, Honoraria; Momenta: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Platelet Disorder Support Association: Consultancy, Honoraria; Agios: Consultancy, Honoraria, Research Funding; Caremark: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Dova: Consultancy, Honoraria; Dova: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Kezar: Research Funding; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Protalex: Consultancy, Honoraria, Research Funding; Kezar: Research Funding; Platelet Disorder Support Association: Consultancy, Honoraria; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Shire: Consultancy, Honoraria; Rigel: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria; Rigel: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria; Merck Sharp Dohme: Consultancy, Honoraria; Protalix: Consultancy, Honoraria; Protalix: Consultancy, Honoraria; Principia: Consultancy, Honoraria, Research Funding; Principia: Consultancy, Honoraria, Research Funding; Protalex: Consultancy, Honoraria, Research Funding; UCB: Consultancy, Honoraria; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; Zafgen: Consultancy, Honoraria; Zafgen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Alnylam: Consultancy, Honoraria, Research Funding; Argenx: Consultancy, Honoraria, Research Funding; Merck Sharp Dohme: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Caremark: Consultancy, Honoraria; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding. Mullally:Janssen: Research Funding. Neuberg:Pharmacyclics: Research Funding; Madrigal Pharmaceuticals: Equity Ownership; Celgene: Research Funding. Zwicker:Daiichi: Consultancy; Quercegen: Research Funding; Parexel: Consultancy; Portola: Consultancy; Incyte: Research Funding; Seattle Genetics: Consultancy; Bayer: Consultancy. Hobbs:Jazz pharmaceuticals: Consultancy; Bayer: Research Funding; Merck: Research Funding; Celgene: Consultancy; Incyte: Consultancy, Research Funding; Agios: Consultancy.

Background.This study aimed to determine the progression-free survival and response rate using early therapeutic intervention in patients with high-risk smoldering multiple myeloma (SMM) using the combination of ixazomib, lenalidomide, and dexamethasone. Methods.Patients enrolled on study met eligibility for high-risk SMM based on the newly defined criteria proposed by Rajkumar et al. (Blood 2014). The treatment plan was designed to be administered on an outpatient basis where patients receive 9 cycles of induction therapy of ixazomib (4mg) at days 1, 8, and 15, in combination with lenalidomide (25mg) at days 1-21 and dexamethasone at days 1, 8, 15, and 22. The induction phase was followed by ixazomib (4mg) and lenalidomide (15mg) maintenance for another 15 cycles. A treatment cycle was defined as 28 consecutive days for a total of 24 months period. Bone marrow samples of all patients were obtained before starting therapy for baseline assessment for minimal residual disease (MRD) testing, whole-exome sequencing (WES), and RNA sequencing of plasma and bone marrow microenvironment cells. Moreover, blood samples were obtained at screening and before each cycle for isolating cell-free DNA (cfDNA) and circulating tumor cells (CTCs). Results.In total, 53 of the planned 62 patients have been enrolled in this study from February 2017 to May 2019. The median age of the patients enrolled was 61 years (range, 41 to 84) with 22 male (41.5%). The analysis was conducted on patients who have completed at least 1 cycle of therapy (n=45). The median follow-up for the trial is 14.4 months (range: 2- 27.6). Interphase fluorescence in situ hybridization (iFISH) was successful in 37 patients (82.2%). High-risk cytogenetics (defined as the presence of t(4;14), 17p deletion, and 1q gain) were found in 20 patients (54%). The median number of cycles completed was 14 cycles (range: 1-24). According to the study's inclusion criteria, baseline markers showed that 15, 14, and 13 patients had 3, 4, and 5 high-risk features, respectively. Moreover, 24 patients (53.3%) met the criteria of high-risk SMM, according to the Mayo 2018 model. The most common grade 3 adverse events were hypertension (6.3%), hypophosphatemia (4.2%), and rash (4.2%). Grade 4 thrombocytopenia and neutropenia were each reported in 4.4% of patients, and hyperglycemia was reported in 2.2%. Stem cells were collected in all eligible patients by the end of the induction phase. As of the abstract date, the overall response rate (partial response or better) in participants who completed at least 1 cycle of treatment was 91.1% (41/45), with 14 Complete Responses (CR, 31.1%), 9 very good partial responses (VGPR, 20%), 18 partial responses (40%), and 4 minimal Responses (MR, 10%). ORR in patients who completed the induction phase (≥9 cycles) was 97% (n= 32/33), with 14(42.4%) and 9 (27.2%) having CR and VGPR, respectively. All patients who had a CR have also achieved a stringent CR. Six patients have completed the treatment protocol and are currently on follow-up. As of July 2019, none of the patients have progressed to overt MM. MRD testing by next-generation sequencing is ongoing for patients who achieved CR or VGPR and will be presented at the meeting. Conclusion.The combination of ixazomib, lenalidomide, and dexamethasone is an effective and well-tolerated intervention in high-risk smoldering myeloma with 91% ORR and 54.7% CR and VGPR to date. The high response rate, convenient schedule and manageable toxicity build on prior studies which have shown efficacy of lenalidomide and dexamethasone in high risk smoldering myeloma. Longer follow-up for disease outcome is ongoing. Disclosures Bustoros, MD: Takeda: Honoraria. Nadeem:Celgene: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Sanofi: Consultancy. Prescott:Janssen: Equity Ownership. Munshi:Takeda: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Adaptive: Consultancy; Abbvie: Consultancy; Abbvie: Consultancy; Adaptive: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Takeda: Consultancy; Oncopep: Consultancy; Oncopep: Consultancy; Amgen: Consultancy; Janssen: Consultancy. Anderson:OncoPep: Other: Scientific founder ; C4 Therapeutics: Other: Scientific founder ; Gilead Sciences: Other: Advisory Board; Janssen: Other: Advisory Board; Sanofi-Aventis: Other: Advisory Board. Richardson:Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Ghobrial:Amgen: Consultancy; Celgene: Consultancy; BMS: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Takeda: Consultancy. OffLabel Disclosure: Ixazomib, Lenalidomide and Dexamethasone is an investigational combination in high-risk smoldering multiple myeloma and has not been approved by the US Food and Drug Administration or any other regulatory agency worldwide for the use under investigation.

In multiple myeloma (MM), despite well-characterized precursor states such as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), there is a lack of sufficient biomarkers to predict disease progression. Most genomic analyses have studied the malignant plasma cells, however, cancers form a complex ecosystem with the immune and stromal microenvironment. To characterize the cellular composition and transcriptional programs of each component of the tumor and microenvironment at different stages of MM progression, we employed single-cell RNA sequencing on 48K plasma and 40.8K immune microenvironmental cells from a cohort of 22 patients with varying stages of disease progression and 9 healthy donors. Expression profiles of plasma cells revealed clear tumor-specific differences in known oncogenic drivers in MM (MMSET/FGFR3, CCND1 and MAFB) as well as other clonally expressed genes (LAMP5, HIST1H1C, and AREG), distinguishing them from healthy plasma cells. We identified a subset of cycling plasma cells in malignant samples, observing a range of proliferative capacity across disease stages. Furthermore, our approach allowed a unique head-to-head comparison of gene expression changes in normal and malignant plasma cells from the same individual, revealing early alterations in genes related to immune modulation (NKBIA) or controlling transcription and differentiation (EID1). Some alterations were patient-specific, while others, such as MHC I overexpression and CD27 loss, were recurrently observed across subsets of the cohort. Analysis of the BM microenvironment demonstrated significant infiltration of natural killer cells, non-classical monocytes/macrophages, and T cells, even in the earliest stages of the disease. Further investigation revealed upregulation of MHC II expression at the mRNA level in CD14+ monocytes/macrophages and yet, intriguingly, analysis by CyTOF and immunohistochemistry revealed a shift towards intracellular localization of MHC II in these cells. Co-culture with MM cell lines was sufficient to induce the decrease of extracellular MHC II, providing strong evidence for MM-induced compromised antigen presentation by macrophages, and hinting at a mechanism of immune evasion. Together, our results provide a comprehensive view at the complex interplay of the immune and malignant cells in different stages of the disease. We demonstrate the immune response beginning in premalignant conditions to be heterogeneous, including compromised antigen presentation as well as alterations in cellular composition and signaling. Consideration of the type of immunological response may prove valuable in determination of progression risk, as well as open up potential strategies for therapy. Citation Format: Nicholas J. Haradhvala, Oksana Zavidij, Tarek H. Mouhieddine, Romanos Sklavenitis-Pistofidis, Jihye Park, Mairead Reidy, Abdallah Flaifel, Benjamin Ferland, Salomon Manier, Mark Bustoros, Daisy Huynh, Marzia Capelletti, Brianna Berrios, Mahshid Rahmat, Chia-Jen Liu, Meng Xiao He, Esteban Braggio, Rafael Fonseca, Yosef Maruvka, Jennifer Guerriero, Melissa Goldman, Eliezer Van Allen, Steven McCarroll, Jamil Azzi, Gad Getz, Irene M. Ghobrial. Single-cell RNA sequencing reveals compromised immune microenvironment in precursor stages of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 139.

Introduction. Multiple myeloma (MM) is a complex and heterogeneous malignancy of plasma cells that has two precursor states: monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). MGUS and SMM are asymptomatic states that eventually give rise to overt MM, with some patients progressing, while others do not. Recent studies in MM pathobiology have highlighted epigenetic alterations that contribute to the onset, progression and heterogeneity of MM. Global hypomethylation of DNA, including tumor suppressor genes, and hypermethylation of B-cell specific enhancers, abnormal histone methylation patterns due to the overexpression of histone methyltransferases such as MMSET, and deregulation of non-coding RNAs along with mutations in different classes of chromatin modulators underline a potential for epigenetic biomarkers in disease prognosis and treatment. This study aimed to define epigenetic pathways that lead to the dynamic regulation of gene expression in MM pathogenesis. Methods. We performed ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) and RNA-seq on 10 MM cell lines and CD138+ plasma cells isolated from bone marrow aspirates of 3 healthy donors, 9 SMM, 8 newly diagnosed MM (NDMM) and 9 relapsed (RRMM) patients. ATAC-seq reads were trimmed of adapters, aligned to hg19 using bowtie2, and filtered for mapping quality >=Q30 using the ENCODE ATAC-seq pipeline. Reads mapping to promoter regions, defined as -400 to +250 bases from a refseq transcription start site, were counted using bedtools for each sample. Promoter read counts were then normalized by the total number of reads in promoters in the sample, scaled to 1 million total reads, and converted to log10(x+1) space. Results. To characterize the epigenetic contribution to disease progression in MM, we first identified accessible promoter regions in normal plasma cells (NPC), SMM, NDMM and RRMM patients and found regions displaying differential accessibility in MM progression. Next, we intersected the list of differential accessible regions (DARs) with matched transcriptome data and observed two main clusters: genes with unaltered transcription profiles and genes in which the dynamics of open chromatin regions (OCRs) correlated with gene expression. Transcriptomic analysis revealed that a large portion of the differentially expressed (DE) genes in SMM remain DE in NDMM as compared to NPCs (882 genes out of 1642 and 1150 DE genes in SMM and NDMM, respectively). Those genes were significantly enriched for pathways like epithelial mesenchymal transition, cell cycle checkpoints and mitosis, KRAS signaling and interleukin-JAK-STAT pathways. To investigate the genes that behaved differently among the stages of disease, we looked at differential accessibility and expression in NDMM and SMM samples, and integrated them with Whole-Genome Bisulfite-Sequencing and 450K DNA-methylation data from MM patients and healthy donors (BLUEPRINT). This analysis led to the identification of novel genes in MM progression, such as the transcriptional repressor ZNF254 and IRAK3, a negative regulator of the TLR/IL1R signaling pathway. Although gene expression data for these genes showed comparable mRNA levels in SMM and NPCs, followed by a significant decrease in NDMM/ RRMM, ATAC-seq revealed a striking drop in promoter accessibility in SMM, NDMM and RRMM cases. Comparison of ATAC-seq peaks to DNA methylation and ChIP-seq data revealed that the altered OCR of IRAK3 is actually hypermethylated in MM patients and marked by H3K4me3, a marker of active promoters, in MM cell lines. Hypermethylation of IRAK3 has been described in hepatocellular carcinoma, where it is associated with poor prognosis. Together, our data suggest that the identified IRAK3 OCR may act as a bivalent domain that loses accessibility in the precursor states and gains DNA methylation in MM progression. Hence, IRAK3 methylation could be a novel prognostic marker in MM. Conclusion. We have generated a global epigenetic map of primary tumors from patients at the smoldering, newly diagnosed and relapsed/refractory stage of multiple myeloma. Integrative analysis of ATAC-seq data with DNA methylome, transcriptome and whole-genome map of active and repressive histone marks in our study led to the identification of IRAK3 as a novel epigenetic biomarker of disease progression. Disclosures Licht: Celgene: Research Funding. Ghobrial:Takeda: Consultancy; BMS: Consultancy; Celgene: Consultancy; Janssen: Consultancy.

Background. Waldenström macroglobulinemia (WM) is a low-grade non-Hodgkin's lymphoplasmacytic lymphoma associated with overproduction of monoclonal IgM protein. It is preceded by an asymptomatic stage, called Smoldering Waldenström Macroglobulinemia (SWM), associated with a high risk of progression to overt disease. Current understanding of progression risk in SWM is based on a few small studies, and it is still unclear how to distinguish the asymptomatic patients who will progress from those who will not. Patients and Methods. We obtained clinical data of all WM patients who had been diagnosed and followed up at Dana-Farber Cancer Institute from 1982 to the end of 2014. Only patients with asymptomatic disease at the time of diagnosis were included in this study to identify risk factors for disease progression. Patients who received chemotherapy for a second cancer, before or after asymptomatic WM diagnosis (n =24), were excluded as chemotherapy might have affected the natural course of disease. Patients who progressed to or were diagnosed later with other types of B-cell lymphoproliferative disorders or Amyloidosis (n =71) and patients with myeloproliferative disorders or thalassemia (n = 4) were all excluded from our cohort. Furthermore, we excluded patients with no morphologic evidence of lymphoplasmacytic infiltration in the bone marrow biopsy (n =37), those without a bone marrow biopsy done at time of diagnosis (n =21), and those who were treated for peripheral neuropathy alone (n =13). Progression was defined based on the Consensus Panel recommendations of the Second International Workshop on WM. Survival analysis was performed using the Kaplan-Meier method and differences between the curves were tested by log-rank test. Effects of potential risk factors on progression rates was examined using Cox proportional-hazards models, with hazard ratios (HRs) and associated 95% confidence intervals (CIs). Results. A total of 439 patients were included in the study. During the 35-year study period and a median follow up of 7.8 years, 317 patients (72.2%) progressed to symptomatic WM. The median time to progression was 3.9 (95% CI 3.2-4.6) years. In the multivariate analysis, IgM ≥ 4,500 mg/dL (adjusted HR 4.65; 95% CI 2.52-8.58; p < 0.001), BM lymphoplasmacytic infiltration ≥ 70% (adjusted HR 2.56; 95% CI 1.69-3.87; p < 0.001), β2-microglobulin ≥ 4.0 mg/dL (adjusted HR 2.31; 95% CI 1.19-4.49; p = 0.014), and albumin < 3.5 g/dL (adjusted HR 2.78; 95% CI 1.52-5.09; p = 0.001) were all identified as independent predictors of disease progression, suggesting those thresholds could be clinically useful for determining high-risk patients. On the other hand, given the continuous nature of these variables, we built a proportional hazards model based on four variables (Bone marrow infiltration percentage, serum IgM, albumin, β2-microglobulin). The model divided the cohort into 3 distinct risk groups: a high-risk group with a median time to progression (TTP) of 1.9 years (95% CI 1.64-2.13), an intermediate-risk group with median TTP of 4.6 years (95% CI 4.31-5.15), and a low-risk group with a median TTP of 8.1 years (95% CI 7.33-8.13)(See Figure). To enhance its clinical applicability, we made the model available as user interface through a webpage and mobile application, where clinicians can enter an individual SWM patient's lab values and get information regarding their risk group and estimated individual risk of progression to symptomatic WM. Conclusion. We have assembled the largest cohort of SWM patients to date, which allowed us to identify four independent predictors of progression to overt disease: BM infiltration ≥ 70%, IgM ≥ 4,500 mg/dL, b2m ≥ 4.0 mg/dL and albumin < 3.5 g/dL. Using those variables in a proportional hazards model, we developed a robust, flexible classification system based on risk of progression to symptomatic WM. This system stratifies SWM patients into low-, intermediate- and high-risk groups and thus has the potential to inform patient monitoring and care. Most importantly, it can help identify high-risk patients who might benefit from early intervention in this rare malignancy. Figure 1. Figure 1. Disclosures Bustoros: Dava Oncology: Honoraria. Kastritis: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; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Prothena: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Soiffer:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Treon:Johnson & Johnson: Consultancy; Janssen: Consultancy, Other: Travel, Accommodations, Expenses; BMS: Research Funding; Pharmacyclics: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding. Castillo:Genentech: Consultancy; Millennium: Research Funding; Abbvie: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Beigene: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Dimopoulos:Amgen: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Bristol-Myers Squibb: Honoraria. Ghobrial:BMS: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Celgene: Consultancy.

Introduction: Multiple Myeloma (MM) is a clonal plasma cell malignancy, accounting for 10% of all hematological malignancies. Genetic analyses of large populations revealed that blood-specific somatic mutations in hematopoietic stem cells (HSCs) are commonly acquired during aging, a new entity labeled: clonal hematopoiesis of indeterminate potential (CHIP). We sought to determine the role of CHIP on survival of MM patients, specifically those receiving immunomodulator (IMiD) maintenance (Lenalidomide or Thalidomide) post autologous stem cell transplant (ASCT). Methods: We collected the cryopreserved, growth factor mobilized peripheral blood of 629 MM patients who underwent ASCT between 2003 and 2011 at the Dana-Farber Cancer Institute (DFCI). Then, we performed targeted next-generation sequencing using a 224-gene panel at a mean depth of coverage of 978X and ultra-low pass whole-genome sequencing at 0.1X to account for tumor contamination. We downloaded (dbGAP # phs000748.v6.p4) the whole-exome sequencing (WES) data of a cohort of 1144 newly diagnosed, untreated MM patients from the Multiple Myeloma Research Foundation (MMRF) Clinical Outcomes in MM to Personal Assessment of Genetic Profile (CoMMpass, NCT0145429) study (MMRC) and the WES data of a cohort of 205 newly diagnosed, untreated MM patients from the Broad Institute dataset. We analyzed their peripheral blood (average coverage of 108X) and tumor (average coverage of 107X) data separately, looking for the same CHIP genes included in our target bait panel. Results: The DFCI cohort had a median age of 58 years [range, 24-83] at time of ASCT and median follow up post ASCT of 8 years [range, 0.1-14.5]. 204 patients (32%) in the DFCI cohort had CHIP at time of ASCT. The most commonly detected mutated genes were DNMT3A, TET2, TP53, ASXL1 and PPM1D. 24 patients (3.8%) developed a second hematological malignancy at a median of 4 years [range, 1-10] post ASCT, half of whom had CHIP. Around 48% of the DFCI cohort received IMiDs as part of induction therapy. Different induction regimens had no effect on CHIP prevalence at time of ASCT. Around 56% of the DFCI cohort received IMiD maintenance, 22% of which received maintenance for at least 3 years [range, 0.06-12.8]. Among those who did not receive IMiD maintenance, patients with CHIP had worse progression free survival (PFS) (p-value < 0.001) and overall survival (OS) (p-value = 0.005). In patients receiving IMiD maintenance, having CHIP had no effect on PFS or OS. On the other hand, the MMRF cohort had a median age of 63 years [range, 27-93] and median follow up of 3.03 years [range, 0-5.9] from time of diagnosis. Around 52% of that cohort underwent ASCT and around 76% of those received IMiD maintenance with a median follow up of 2.7 years [range, 0-5.5] from time of ASCT. Furthermore, 200 patients of the MMRF cohort have follow-up samples of both tumor and peripheral blood that had targeted sequencing done by a 562-gene panel that included our genes of interest. Similarly, when studying the genomic results of 139 out of 1144 MMRF patients, as well as the 205 patients from the Broad Institute dataset, we detected CHIP in 25.6% of them and the top 5 most commonly mutated genes were similar to those of our cohort. Conclusion: CHIP is a common entity among MM patients, reaching a prevalence of up to 32%, that predicts a worse PFS and OS in those who do not receive IMiD maintenance therapy post ASCT. As expected, IMiD maintenance improves outcome in MM patients, with and without CHIP. In patients with CHIP, the use of IMiDs abrogated the deleterious effect imposed by CHIP to a point that outcome is identical to that of patients without CHIP. Figure Figure. Disclosures Bustoros: Dava Oncology: Honoraria. Munshi:OncoPep: Other: Board of director. Anderson:Gilead: Membership on an entity's Board of Directors or advisory committees; OncoPep: Equity Ownership, Other: Scientific founder; Celgene: Consultancy; C4 Therapeutics: Equity Ownership, Other: Scientific founder; Bristol Myers Squibb: Consultancy; Millennium Takeda: Consultancy. Richardson:Oncopeptides: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Soiffer:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Ghobrial:Celgene: Consultancy; Janssen: Consultancy; BMS: Consultancy; Takeda: Consultancy.

Introduction: In multiple myeloma (MM), despite well-characterized precursor states such as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), there is a lack of sufficient biomarkers to predict mechanisms of disease progression. Most genomic analyses have sought biomarkers by study of the malignant plasma cells, however, cancers form a complex ecosystem with the immune and stromal microenvironment. Thus, to characterize the cellular composition and transcriptional programs of each component of the tumor and microenvironment at different stages of MM progression, we employed a single-cell RNA sequencing on a cohort of 22 patients and 9 healthy donors. Methods: We performed 10X droplet-based single-cell RNA sequencing using CD138-expressing plasma cells and microenvironmental populations isolated from bone marrow (BM) aspirates of patients with MGUS (n=6), low-risk SMM (n=3), high-risk SMM (n=13), newly diagnosed MM (n=8) and from 9 healthy donors (NBM). We collected a total of ~88.8K cells, comprising ~48K CD138+ cells (~36.4 from MM stages) and ~40.8K CD45+/CD138- cells (~30.8 from MM stages).Raw read data was processed using the Cell Ranger pipeline to obtain a gene-by-cell expression matrix, which was used to identify cell types and transcriptional programs by clustering and non-negative matrix factorization. Results: Expression profiles of plasma cells revealed clear tumor-specific differences including known oncogenic drivers in MM (MMSET/FGFR3, CCND1 and MAFB) as well as Lysosome-associated Membrane Protein 5 (LAMP5),Histone Cluster 1 H1 Family Member C (HIST1H1C) and Amphiregulin (AREG) distinguishing them from healthy plasma cells. We identified a subset of cycling plasma cells, observing a range of proliferative activity of the malignant fraction. Furthermore, our approach allowed a unique head-to-head comparison of gene expression changes in normal and malignant plasma cells in the MGUS and SMM patients within an individual, excluding inter-individual variation. We were able to discriminate malignant from non-malignant plasma cells and identify transcriptional alterations including known drivers, genes related to immune modulation (NKBIA) or controlling transcription and differentiation (EID1).Some alterations were patient-specific, while others, such as MHC I overexpression and CD27 loss, were recurrently observed across subsets of the cohort. Analysis of BM microenvironment in several stages of MM progression demonstrated a striking shift in the composition of immune cells with significant infiltration of natural killer cells, non-classical monocytes/macrophages, and T cells, enriched even in the earliest stages of the disease. Further investigation revealed significant upregulation of HLA expression at the mRNA level in CD14+ monocytes/macrophages. Intriguingly, comparison of healthy and patient samples by CyTOF showed downregulation of surface MHC II representation in the corresponding cell type, and moreover, co-culture with MM cell lines induced a sharp decrease of extracellular MHC II. This provided strong evidence for compromised antigen presentation by macrophages in the disease setting, hinting at a mechanism of immune evasion. Additionally, expression signatures in cytotoxic T-cells indicated a substantial skewing towards either granzyme B/H- or granzyme K-expressing memory cell-like transcriptional program. In a subgroup of patients, we found a strong simultaneous enrichment of the anti-viral/anti-bacterial gene expression signature for interferon type-1 activated genes in CD14+ monocytes/macrophages and T cells. Together, our results provide a comprehensive view at the complex interplay of the immune and malignant cells in different stages of the disease. We, for the first time, demonstrate the immune response beginning in premalignant conditions to be heterogeneous, including compromised antigen presentation as well as alterations in cellular composition and signaling. Consideration of the type of immunological response may prove valuable in determination of progression risk, as well as open up potential strategies for therapy. Disclosures Bustoros: Dava Oncology: Honoraria. Ghobrial:Celgene: Consultancy; Janssen: Consultancy; BMS: Consultancy; Takeda: Consultancy.

Background. This study aimed to determine the progression-free survival and response rate using early therapeutic intervention in patients with high-risk smoldering multiple myeloma (SMM) using the combination of ixazomib, lenalidomide, and dexamethasone. Methods. Patients enrolled on study met eligibility for high-risk SMM based on the newly defined criteria proposed by Rajkumar et al., Blood 2014. The treatment plan was designed to be administered on an outpatient basis where patients receive 9 cycles of induction therapy of ixazomib (4mg) at days 1, 8, and 15, in combination with lenalidomide (25mg) at days 1-21 and Dexamethasone at days 1, 8, 15, and 22. This induction phase is followed by ixazomib (4mg) and lenalidomide (15mg) maintenance for another 15 cycles. A treatment cycle is defined as 28 consecutive days, and therapy is administered for a total of 24 cycles total. Bone marrow samples from all patients were obtained before starting therapy for baseline assessment, whole exome sequencing (WES), and RNA sequencing of plasma and bone marrow microenvironment cells. Moreover, blood samples were obtained at screening and before each cycle to isolate cell-free DNA (cfDNA) and circulating tumor cells (CTCs). Stem cell collection is planned for all eligible patients. Results. In total, 26 of the planned 56 patients were enrolled in this study from February 2017 to April 2018. The median age of the patients enrolled was 63 years (range, 41 to 73) with 12 males (46.2%). Interphase fluorescence in situ hybridization (iFISH) was successful in 18 patients. High-risk cytogenetics (defined as the presence of t(4;14), 17p deletion, and 1q gain) were found in 11 patients (61.1%). The median number of cycles completed was 8 cycles (3-15). The most common toxicities were fatigue (69.6%), followed by rash (56.5%), and neutropenia (56.5%). The most common grade 3 adverse events were hypophosphatemia (13%), leukopenia (13%), and neutropenia (8.7%). One patient had grade 4 neutropenia during treatment. Additionally, grade 4 hyperglycemia occurred in another patient. As of this abstract date, the overall response rate (partial response or better) in participants who had at least 3 cycles of treatment was 89% (23/26), with 5 Complete Responses (CR, 19.2%), 9 very good partial responses (VGPR, 34.6%), 9 partial responses (34.6%), and 3 Minimal Responses (MR, 11.5%). None of the patients have shown progression to overt MM to date. Correlative studies including WES of plasma cells and single-cell RNA sequencing of the bone microenvironment cells are ongoing to identify the genomic and transcriptomic predictors for the differential response to therapy as well as for disease evolution. Furthermore, we are analyzing the cfDNA and CTCs of the patients at different time points to investigate their use in monitoring minimal residual disease and disease progression. Conclusion. The combination of ixazomib, lenalidomide, and dexamethasone is an effective and well-tolerated intervention in high-risk smoldering myeloma. The high response rate, convenient schedule with minimal toxicity observed to date are promising in this patient population at high risk of progression to symptomatic disease. Further studies and longer follow up for disease progression are warranted. Disclosures Bustoros: Dava Oncology: Honoraria. Munshi:OncoPep: Other: Board of director. Anderson:C4 Therapeutics: Equity Ownership; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Takeda Millennium: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Oncopep: Equity Ownership. Richardson:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ghobrial:Celgene: Consultancy; Takeda: Consultancy; Janssen: Consultancy; BMS: Consultancy.

Background This study aimed to determine the benefit of early therapeutic intervention with the combination of elotuzumab, Lenalidomide, and Dexamethasone in patients with high-risk smoldering multiple myeloma (SMM). ClinicalTrials.gov Identifier: NCT02279394. Aims The overarching objective of this trial is to determine progression free survival to symptomatic multiple myeloma (MM). Furthermore, the study examined whether genomic studies can help in determining patients who would benefit the most from this early therapeutic intervention. Methods Patients enrolled in this study met eligibility for high-risk SMM based on the newly defined criteria proposed by Rajkumar et al, Blood 2014. Patients were administered weekly elotuzumab (10 mg/kg) on days 1, 8, 15, and 22 for the first two 28-day cycles while receiving lenalidomide on days 1-21. For cycles 3-8, patients were administered elotuzumab infusions on days 1, 8, and 15. dexamethasone (40mg) was given on days 1, 8 and 15 to 40 of the 50 enrolled patients. After 8 cycles or best response, patients were given the option to mobilize with either cyclophosphamide or plerixafor and collect stem cells for future transplant. Patients were then allowed to continue on maintenance therapy where they were administered elotuzumab (20 mg/kg) on day 1, in combination with lenalidomide days 1-21 of a 28-day cycle. Bone marrow (BM) samples of 32 patients were obtained before starting therapy for baseline assessment and whole exome sequencing (WES) of plasma cells. Results In total, 50 patients were enrolled on this study from January 2015 and completed accrual in December 2016, with the participation of eight sites. The median age of enrolled patients was 62 years (range, 29-79) with 18 males (36%) and 32 females (64%). Interphase fluorescence in situ hybridization (iFISH) detected high-risk cytogenetics (defined by the presence of 17p deletion, t(4;14), and 1q gain) in 20 patients. The median time to response was 2.8 months (range, 1.8-4.6). The most common toxicities were fatigue (92%), followed by diarrhea (72%), and hyperglycemia (62%). The most common grade 3 or more adverse events were hypophosphatemia (34%), neutropenia (26%), and lymphocyte count decreased (22%). Three patients (6%) had grade 4 hypophosphatemia during treatment. Additionally, grade 4 cholecystitis, cataract, lymphocyte count increase, hyperglycemia, neutropenia, and thrombocytopenia occurred in one patient (2%). Diabetic Ketoacidosis and sepsis led to death in a patient (2%). Stem cell collection was successful in all mobilized patients to date. As of this abstract date, the overall response rate is 84% (41/49). There were 3 complete responses (6%), 18 very good partial responses (37%), 20 partial responses (41%), 5 minimal responses (10%), 3 stable disease (6%), and 2 unevaluable patients. All the study participants except for three have finished treatment and are currently under follow up. None of the patients showed progression to overt MM to date. We continue to collect data for progression free survival. WES was performed on 32 samples at the time of initiation of therapy. Recurrent mutations in the MAPK pathway (KRAS, NRAS) and tumor suppressor gene, TP53, were detected in 40% of the cases (16% and 24%, respectively), while mutations in the NF-KB and plasma cell differentiation pathways were present in 13% of patients. Somatic copy number alterations (SCNAs) were called based on WES: 1q duplication, 13q, 17p, and 1p deletions were identified in 25, 31, 12, and 7% of cases, respectively. Interestingly, in 6 patients, high-risk SCNAs (1q gain and 17p deletion) were not reported in iFISH but were detected by WES. The analysis of these 32 samples showed that patients who are harboring mutations in the DNA repair pathway genes, had modest response to treatment. Finally, we are analyzing the transcriptomic profile of CD138 negative cells, which represent the BM microenvironment cells (immune and stromal cells) to characterize the BM microenvironment at baseline and end of treatment, and thus, elucidate the role of these cells in the differential response to therapy. Conclusion The combination of elotuzumab, lenalidomide, and dexamethasone is well tolerated and demonstrates a high response rate with no progression to overt MM to date. Correlation with genomic studies can help define patients who benefit the most from this early therapeutic intervention. Disclosures Ghobrial: Takeda: Consultancy; Janssen: Consultancy; BMS: Consultancy; Celgene: Consultancy. Bustoros:Dava Oncology: Honoraria. Badros:GSK: Research Funding; Celgene: Consultancy, Research Funding; Karyopharm: Research Funding. Matous:Celgene: Consultancy, Honoraria, Speakers Bureau. Rosenblatt:Merck: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Jakubowiak:Karyopharm: Consultancy, Honoraria; SkylineDx: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Adaptive Biotechnologies: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Usmani:Abbvie, Amgen, Celgene, Genmab, Merck, MundiPharma, Janssen, Seattle Genetics: Consultancy; Amgen, BMS, Celgene, Janssen, Merck, Pharmacyclics,Sanofi, Seattle Genetics, Takeda: Research Funding. Zonder:Celgene: Consultancy, Honoraria; Pharmacyclics: Other: DSMC; Janssen: Honoraria; Takeda: Honoraria; Alnylam: Honoraria; Coelum: Honoraria; BMS: Research Funding. Munshi:OncoPep: Other: Board of director. Anderson:Gilead: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy; C4 Therapeutics: Equity Ownership, Other: Scientific founder; OncoPep: Equity Ownership, Other: Scientific founder; Millennium Takeda: Consultancy; Celgene: Consultancy. Richardson:Amgen: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Waldenström Macroglobulinemia (WM) is a low-grade B-cell lymphoma characterized by disease progression from IgM MGUS to asymptomatic and then symptomatic disease states. We profiled exosomes from the peripheral blood of patients with WM at different stages (30 smoldering/asymptomatic WM, 44 symptomatic WM samples and 10 healthy controls) to define their role as potential biomarkers of disease progression. In this study, we showed that circulating exosomes and their miRNA content represent unique markers of the tumor and its microenvironment. We observed similar levels of miRNAs in exosomes from patients with asymptomatic (smoldering) and symptomatic WM, suggesting that environmental and clonal changes occur in patients at early stages of disease progression before symptoms occur. Moreover, we identified a small group of miRNAs whose expression correlated directly or inversely with the disease status of patients, notably the known tumor suppressor miRNAs let-7d and the oncogene miR-21 as well as miR-192 and miR-320b. The study of these miRNAs' specific effect in WM cells could help us gain further insights on the mechanisms underlying WM pathogenesis and reveal their potential as novel therapeutic targets for this disease.

Introduction: Multiple Myeloma (MM) is a clonal plasma cell malignancy, accounting for 10% of all hematological malignancies. Genetic analyses of large populations revealed that blood-specific somatic mutations in hematopoietic stem cells (HSCs) are commonly acquired during aging, a new entity labeled: clonal hematopoiesis of indeterminate potential (CHIP). We sought to determine the role of CHIP on survival of MM patients, specifically those receiving immunomodulators (IMiDs) maintenance (Lenalidomide or Thalidomide) post autologous stem cell transplant (ASCT). Methods: We tested cryopreserved HSCs of 629 MM patients who underwent ASCT between 2003 and 2011 at the Dana-Farber Cancer Institute. We used a target bait panel of 224 genes and performed deep-targeted sequencing at 978x coverage and ultra-low pass whole-genome sequencing at 0.1x to account for tumor contamination. Sequencing data was analyzed using ichorCNA, MuTect, and Strelka and mutation annotations were based on reported mutations in the literature and databases (ClinVar, COSMIC, cBioPortal, TCGA, and ExAC). Results: Our cohort had a median age of 58 years [24-83] at time of ASCT and median follow up post ASCT of 8 years [0.1-14.5]. 24% of patients had CHIP at time of ASCT, which is statistically similar to the 30% reported in non-Hodgkin's lymphoma (NHL), (Gibson et. al, JCO, 2017). The most commonly detected mutated genes were DNMT3A, TET2, TP53 and ASXL1. Acquiring mutations positively correlated with age (p=0.004). In contrast to NHL, PPM1D was not significantly mutated in MM (40% vs. 3.3%). 27 patients (4.3%) developed a second hematological malignancy at median of 4 years [1-10] post ASCT, of which 10 had CHIP. 22% received at least 3 years [0.06-12.8] of IMiD maintenance. Among those who did not receive IMiD maintenance, CHIP was associated with worse progression free survival (PFS) (p=0.047) where PFS at 3 years post ASCT was 31% (95%CI: 25-38) for those without CHIP vs. 15% with CHIP (95%CI: 7-25). In patients with IMiD maintenance, CHIP had no effect on PFS or overall survival (OS) (p=0.9). In patients with CHIP, receiving IMiD was associated with a better OS and PFS below the age of 58 and better PFS only in those above 58. In the overall cohort, CHIP was not associated with more adverse outcomes, which could be attributed to low OS and PFS in MM or the use of IMiD in 56% of this cohort. IMiD maintenance was associated with better OS (p Conclusion: CHIP is a common entity among MM patients that predicts a worse PFS in those who do not receive IMiD maintenance therapy post ASCT. The use of IMiDs abrogated the deleterious effect imposed by CHIP in this cohort. Larger cohorts with longer follow up are needed, especially in the era of novel agents and long-term use of Lenalidomide maintenance. Citation Format: Tarek H. Mouhieddine, Jihye Park, Robert Redd, Christopher J. Gibson, Salomon Manier, Amin Nassar, Kalvis Hornburg, Marzia Capelletti, Daisy Huynh, Romanos Sklavenitits Pistofidis, Mark W. Bustoros, Saud H. AlDubayan, Brendan Reardon, Cody J. Boehner, Henry Dumke, Chia-Jen Lui, Darlys Schott, Eliezer M. Van Allen, Robert L. Schlossman, Nikhil C. Munshi, Kenneth C. Anderson, David P. Steensma, Jacob P. Laubach, Paul G. Richardson, Jerome Ritz, Benjamin L. Ebert, Robert J. Soiffer, Donna Neuberg, Irene M. Ghobrial. Immunomodulator maintenance post autologous stem cell transplant predicts better outcome in multiple myeloma patients with clonal hematopoiesis of indeterminate potential [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2954.