Landgren, Ola

Introduction The pathogenic role of somatic non-coding (nc) single nucleotide variants (SNVs) is underexplored in multiple myeloma (MM) and additional characterization of these regions has the potential to provide significant new insights into disease progression. To investigate the role of ncSNVs and their relationship with MM pathogenesis, we have characterized a novel series of WGS from 294 cases of MGUS, SMM, and MM using computational tools optimized to identify functional driver SNVs in these regions. We hypothesize the ncSNVs that co-localize to sites of super-enhancers (SEs) active in plasma cells (PC) are sites of high functional impact SNVs and these mutations lead to the dysregulated expression of genes that should be silent at the terminally differentiated stage of PCs, providing a selective advantage that shapes the fitness of the MM genomic landscape. Methods We analyzed 294 high-coverage matched tumor/normal pairs (80x tumor and 40x normal) derived from 21 MGUS, 86 SMM, 167 NDMM and 40 RRMM. In addition to previously sequenced samples, newly sequenced patients were obtained from NYU Langone Health, Memorial Sloan Kettering Cancer Center, University of Alabama at Birmingham and University of Miami following IRB-approved informed consent. DNA was extracted from CD138+ purified bone marrow plasma cells using standard approaches. We used the MGP1000 (https://github.com/pblaney/mgp1000) to process sequencing data which employs a union-consensus mechanism for determining the final set of variants. We collected enhancer elements (E/SEs) active in GC B-cells, ABC-DLBCL and GBC-DLBCL (Bal, et al. Nature, 2022) and PC specific E/SEs (Loven, et al. Cell 2013). FunSeq2 was used to score ncSNVs. GRAM was used to predict how variants alter TF binding and gene expression in a subset of 6 cases with paired WGS in our series and will expand this analysis on a validation set of 263 NDMM and 93 RRMM cases from University-Hospital Heidelberg enrolled in the GMMG-HD6 clinical trial. Results We identified 1,952,232 high-quality SNVs with 18,199 (0.93%) accumulating in 280 focal sites we termed “mutationally enriched regions” or MERs. To discern SNVs in MERs with the highest potential for imparting a selective advantage, we clustered mutations based on the density of FunSeq2 impact scores which uses reference data contexts on sequence conservation, modification of transcription factor (TF) binding, and gene linkage to regulatory elements and network hubs from pan-cancer studies. We show that MERs are enriched for ncSNVs with high impact scores (mean=2.57) compared to random similarly-sized regions of the genome (Fisher's exact test P<9.7e-12, OR=10.10 [3.88-37.40]). The high impact ncSNVs (hi-ncSNVs) in MERs (n=220) account for 8.09% of all hi-ncSNVs and are present in 46.3% of cases (136/294) with some patients having up to 7. The proportion of cases carrying a MER hi-ncSNVs was similar across disease stages (MGUS=42.9%, SMM=46.5%, MM=40.7%, and RR=47.5%). Analysis of the VAF of MER hi-ncSNVs shows a minor shift towards more clonal versus subclonal mutations (53.6% vs 46.4% VAF>=0.25) suggesting some high impact mutations are acquired in the GC but additional hi-ncSNV are acquired later in PC development, providing evidence that hi-ncSNVs accumulate in MERs throughout disease progression. We mapped these hi-ncSNVs to associated genes then intersected the loci with E/SEs active in GCBs and PCs to determine their functional context. This approach identified 12 genes affected by hi-ncSNVs including the previously identified nc-drivers NEAT1, MIR142, ZCCHC7, and IGLL5 as well as the PC differentiation genes IRF8, BACH2, proliferation genes RHOH, SPRED2, known coding MM drivers CCND1, ZFP36L1, and chr1q genes BTG2 and CROCC. We predicted the effect of ncSNVs on expression through modulation of TF binding at this set of putative nc drivers in MM and identified a trend towards increase in expression of SPRED2, CCND1, NEAT1, and IGLL5 compared to non-mutated cases (P=0.089). We will present data on the validation of this set of genes on a larger set of data derived from the Heidelberg group. Conclusions We identified a set of 12 putative nc driver genes in MM that modify expression and have the potential to significantly alter the pathogenesis of MM by providing a selective survival advantage. We will present the impact of these by clinical stage and on outcome.

Background: SAR442257 (SAR'257) is a trispecific antibody that targets CD38, CD3 and CD28. Simultaneous CD3 and CD28 binding triggers T cell co-signaling, and additional CD38 recognition directs the T cells to CD38+ cancer cells such as multiple myeloma (MM) and non-Hodgkin lymphoma (NHL). This is a first-in-human phase 1 study investigating the safety, efficacy, pharmacokinetic (PK) and pharmacodynamic (PD) profile of SAR'257 in patients (pts) with refractory and relapsed (rr) MM and rrNHL. Methods: This is a multicenter, international, open-label, dose-escalation study (NCT04401020) of SAR'257 in pts with rrMM refractory to standard-of-care (SOC) options, including anti-CD38 monoclonal antibodies, and in pts rrNHL without any SOC options. SAR'257 was administered intravenously with lead-in doses (Day 1−5) in the first week, followed by twice weekly (BIW) or once weekly (QW) dosing; 11 target dose levels (TDLs) in pts with rrMM (9 TDLs: 0.06-11 µg/kg BIW; 2 TDLs: 18-27 µg/kg QW), and 2 TDLs in pts with rrNHL (2 µg/kg BIW and 4 µg/kg QW). Results: As of February 19, 2024, 47 pts (rrMM, n=40; rrNHL, n=7) received SAR'257. The median ages (years) were 64 (rrMM; range: 40−84) and 70 (rrNHL; range: 18−75). The median number of prior lines was 5 (range: 3−12) for rrMM and 5 (range: 2−7) for rrNHL cohort. In rrMM cohort, all (100%) pts had prior exposure to an anti-CD38 monoclonal antibody (MAb) and were refractory to anti-CD38 and in rrNHL cohort all were anti-CD38 naïve. The median time from last anti-CD38 dose was 2.7 (range: 1−65) months for rrMM cohort. Safety analysis revealed that 68% (n=32) pts had treatment-emergent adverse events (TEAEs; 26 pts in rrMM and 6 pts in rrNHL); 21.3% pts (n=10) Grade (G) ≥3 TEAEs (7 in rrMM and 3 in rrNHL). Cytokine release syndrome (CRS) was the most common TEAE, occurring in 52.5% of rrMM pts across all TDLs (n=21; G≥3 in 1 pt from 11 µg/kg BIW TDL) and in 57.1% of rrNHL pts (n=4; no G≥3) at the two TDLs tested. Repetitive CRS episodes (>1 episode) were more frequent at higher TDLs. Infusion-related reactions (IRRs; any G) were observed in 22.5% pts with rrMM (n=9; no G≥3) and in 28.5% pts with rrNHL (n=2; G≥3 in 1 pt). Epstein-Barr virus (EBV) infection/reactivation was reported in 17.5% (n=7; G≥3 in 4 pts) and 28.6% (n=2; no G≥3) pts with rrMM and rrNHL respectively. Further, 15% (n=6, G≥3 in 2 pts) from rrMM and 14.3% (n=1; G2 CMV reactivation) pts from rrNHL cohort reported cytomegalovirus (CMV) infection/reactivation. One case of immune effector cell-associated neurotoxicity syndrome (ICANS) was reported (G4) in the rrNHL cohort. Four dose-limiting toxicities (DLTs) were observed in the rrMM cohort [1 at 4 µg/kg BIW (G3 hepatotoxicity); 1 at 11 µg/kg BIW (G5 CRS−EBV reactivation; and 2 at 27 µg/kg QW (G3 CMV infection reactivation and G3 febrile neutropenia in same pt)]. Three DLTs were observed in the rrNHL cohort (2 at 2 µg/kg BIW [G4 neutropenia and G4 thrombocytopenia; same pt] and 1 at 4 µg/kg QW [ICANS G4]). For pts with rrMM, the maximum plasma concentration of SAR'257 reached within or above the theoretical efficacious range (0.1−1nM; extrapolated from ex vivo models), starting at 8 µg/kg BIW and 18 µg/kg QW in the first treatment cycle. As of July 08, 2024, the overall response rate (ORR), defined as partial response (PR) or better, was 5% (n=2) in the rrMM cohort: 1 pt exhibited stringent complete response (duration of response [DOR]=8.1 months, on-going) and 1 showed a complete response (CR) at 27 µg/kg QW TDL. In rrNHL cohort, the ORR was 14.3%, 1 pt achieved PR (DOR=7.1 months) at 2 µg/kg BIW TDL. The disease control rate (stable disease or better for >8 weeks) was 60% (n=24) and 28.6% (n=2) in the rrMM and rrNHL cohorts respectively. For both cohorts exploratory biomarker analysis revealed that: (1) SAR'257 treatment activated peripheral blood T cells and reduced regulatory T cell numbers and CD4/CD8 ratio; (2) CD38 expression on plasma cells positively corelated with time since the last anti-CD38 MAb dose; (3) Among the pts experiencing CRS, the peak values of cytokines (Interleukin (IL)-6, IL-8, and C-reactive protein) were significantly higher during the first cycle in comparison to subsequent cycles. Conclusion: This Phase 1 study of SAR'257 showed an anti-tumor response in a small number of pts from the rrMM and rrNHL cohorts. Due to safety concerns, in particular high rates of EBV and CMV reactivation and recurrent episodes of CRS in the higher dose levels, the study was terminated during dose escalation.

PURPOSE Outcomes for patients with newly diagnosed multiple myeloma (NDMM) are heterogenous, with overall survival (OS) ranging from months to over 10 years. METHODS To decipher and predict the molecular and clinical heterogeneity of NDMM, we assembled a series of 1,933 patients with available clinical, genomic, and therapeutic data. RESULTS Leveraging a comprehensive catalog of genomic drivers, we identified 12 groups, expanding on previous gene expression–based molecular classifications. To build a model predicting individualized risk in NDMM (IRMMa), we integrated clinical, genomic, and treatment variables. To correct for time-dependent variables, including high-dose melphalan followed by autologous stem-cell transplantation (HDM-ASCT), and maintenance therapy, a multi-state model was designed. The IRMMa model accuracy was significantly higher than all comparator prognostic models, with a c-index for OS of 0.726, compared with International Staging System (ISS; 0.61), revised-ISS (0.572), and R2-ISS (0.625). Integral to model accuracy was 20 genomic features, including 1q21 gain/amp, del 1p, TP53 loss, NSD2 translocations, APOBEC mutational signatures, and copy-number signatures (reflecting the complex structural variant chromothripsis). IRMMa accuracy and superiority compared with other prognostic models were validated on 256 patients enrolled in the GMMG-HD6 (ClinicalTrials.gov identifier: NCT02495922 ) clinical trial. Individualized patient risks were significantly affected across the 12 genomic groups by different treatment strategies (ie, treatment variance), which was used to identify patients for whom HDM-ASCT is particularly effective versus patients for whom the impact is limited. CONCLUSION Integrating clinical, demographic, genomic, and therapeutic data, to our knowledge, we have developed the first individualized risk-prediction model enabling personally tailored therapeutic decisions for patients with NDMM.

Background: Despite the development and approval of effective therapies for multiple myeloma (MM), MM remains an incurable disease. Moreover, patients with high-risk cytogenetics, like translocation t(4;14), continue to have a poor prognosis compared to standard-risk patients. No novel agents have been approved specifically for this population. There remains an unmet need for precision therapies for MM that can target specific drivers of high-risk MM like t(4;14). Multiple myeloma SET domain-containing protein (MMSET) overexpression observed in 100% of patients with t(4;14) acts through the MMSET-H3K36me2 axis, which promotes malignant transformation through regulation of multiple oncogenic programs. KTX-1001, a methyl transferase inhibitor, is a novel, first-in-class, potent, oral, small molecule that inhibits MMSET and the methylation of lysine K36. KTX-1001 had favorable drug-like properties, demonstrated in vivo activity, and was well tolerated in non-clinical studies. Based on these data, KTX-1001 is now being studied in a Phase 1 dose escalation and expansion study in relapsed and refractory multiple myeloma (RRMM). Study Design and Methods: This multi-country, Phase 1, open-label study (NCT05651932) is designed to assess the safety, tolerability, and initial clinical activity of KTX-1001. The study will also examine the recommended phase 2 dose (RP2D), pharmacokinetics (PK) and pharmacodynamics (PD). Part A of this trial includes an accelerated titration, followed by 3+3 dose escalation with backfill of cohorts for dose optimization prior to moving to Part B, which is an expansion phase at the RP2D (please see Figure 1 for study design schematic). The expansion phase will only include patients with t(4;14). KTX-1001 will be administered orally daily and given until disease progression, unacceptable toxicity, or withdrawal from the study. Estimated enrollment for Parts A and B will be approximately 60 patients. The study will enroll patients with RRMM who have received ≥3 prior lines of therapy, including a proteasome inhibitor (PI), immunomodulatory drug (IMiD), and anti-CD38 antibody. Patients must have measurable disease, be ≥18 years of age, have an Eastern Cooperative Oncology Group score of ≤2, and adequate bone marrow, liver, and kidney function. Key exclusion criteria include history of or current plasma cell leukemia, active central nervous system (CNS) disease, or active unstable cardiovascular function. The primary endpoints of safety and tolerability include incidence of dose-limiting toxicity (DLTs), treatment-emergent adverse events (AEs), and treatment-related AEs. Secondary endpoints include plasma concentrations of KTX-1001 and efficacy outcomes such as objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Exploratory biomarker and pharmacodynamic assessments will also be performed. The sample size was not determined by formal statistical methods but will be sufficient to provide preliminary information on safety, PK, PD, and efficacy. Statistical analyses will be primarily descriptive. Conclusion: This Phase 1 study will evaluate a potential treatment for RRMM utilizing KTX-1001, which is a novel, first-in-class, potent, oral small-molecule MMSET inhibitor. The study is open and actively enrolling patients at centers in the United States, Spain, France, and Canada.

Summary: The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.

AbstractThe 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.

Background CD38 is highly expressed on MM cells, hence anti-CD38 agents are of interest as a therapeutic approach in MM. The anti-CD38 monoclonal antibody, dara, as mono- or combination therapy, has substantially improved efficacy outcomes in RRMM, including in heavily pretreated pts. However, many pts relapse and new therapeutic approaches are needed, particularly for pts R/R to dara. TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit. Its unique mechanism of action involves specific binding to CD38+ cells, forced internalization into the target cells, retrograde transport to the cytosol, and irreversible, enzymatic inactivation of target cell ribosomes to cause apoptosis. TAK-169 showed potent, rapid in vitro activity on CD38-expressing cell lines and in vivo efficacy in MM mouse xenograft tumor models with a wide CD38 expression range when administered intravenously (IV) once weekly (QW) or once every 2 weeks (Q2W). Activity was also shown in ex vivo assays from 6 pt bone marrow aspirate (BMA) samples, including from a dara-resistant pt (EC50 5 nM). TAK-169 retained in vitro activity in the presence of dara with modest shifts in EC50 noted at higher dara concentrations. In contrast to dara, TAK-169 has direct tumor cell kill activity that is independent of a pt's immune function status and may therefore be effective in a dara-resistant setting. Accordingly, this phase 1 study will assess safety, tolerability, preliminary efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) of TAK-169 in RRMM. Methods This first-in-human, multicenter, open-label study (NCT04017130; Figure) comprises dose escalation (Part 1) and expansion (Part 2). Eligible pts must be aged ≥18 years with a confirmed diagnosis of MM. Pts enrolled in Part 1 should not be candidates for available therapies known to confer clinical benefit in RRMM. In part 2, pts enrolled should have received ≥3 prior lines of therapy, or ≥2 if one included a PI and IMiD combined. Prior anti-CD38 therapy (including dara) is permitted, except in the Part 2 anti-CD38 therapy-naive expansion cohort. In Part 1, the primary objective is to assess safety/tolerability of TAK-169 in pts with RRMM, and determine maximum tolerated dose/recommended Phase 2 dose (MTD/RP2D). Secondary objectives include efficacy, PK, PD and immunogenicity of TAK-169. Approximately 60 pts are planned to be enrolled to receive IV TAK-169 QW on Days 1/8/15/22 in 28-day cycles. Dosing will start at 50 μg/kg, with subsequent dose levels of 100, 200, 335, 500, 665 μg/kg. A 2nd Q2W dose escalation cohort may be initiated, starting at the QW MTD. The Bayesian Logistic Regression Model with overdose control will be used for dose escalation cohort 2 and for all subsequent dose escalation cohorts, and other non-DLT-safety, clinical, PK, and PD data will be considered. In Part 2, the primary objective is preliminary evaluation of TAK-169 clinical activity in RRMM. Secondary objectives include further evaluating safety, efficacy, PK, PD, and immunogenicity of TAK-169. Part 2 will enroll approximately 54 pts into dara RR (QW and Q2W dosing) and anti-CD38 therapy-naïve (QW dosing) cohorts. TAK-169 will be administered at the MTD/RP2D (QW and Q2W) determined in Part 1. Response will be monitored longitudinally using orthogonal approaches. M-protein levels in serum and urine will be measured each cycle to determine objective responses by International Myeloma Working Group (IMWG) criteria. Minimal residual disease status in pts suspected to be at complete response will be assessed. Circulating free DNA (cfDNA) will be collected from longitudinal plasma samples for disease monitoring. Baseline cytogenetic data will be collected, and TAK-169 efficacy will be assessed in pts with high-risk cytogenetics. Serial blood samples will be used to characterize PK and PD of TAK-169 after IV administration, and to assess the presence of antidrug antibodies. BMA samples collected at screening will be used to evaluate baseline expression of candidate biomarkers. Toxicity will be evaluated using National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 5. Efficacy analyses will use descriptive statistics with a 95% confidence interval and the Kaplan-Meier method. PK parameters and immunogenicity status will be summarized using descriptive statistics. Recruitment is ongoing. Figure Disclosures Kumar: Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding. Cornell:Takeda: Consultancy; KaryoPharm: Consultancy. Landgren:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Other: IDMC; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Theradex: Other: IDMC; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: 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; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ailawadhi:Cellectar: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy. Higgins:Molecular Templates, Inc.: Employment, Equity Ownership. Willert:Molecular Templates: Employment. Waltzman:Molecular Templates, Inc.: Employment, Equity Ownership. Lin:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Zhang:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Lublinsky:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Dash:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Hanley:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Manoharan:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Leichter:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Ottinger:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Labotka:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Newcomb:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Vorog:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. OffLabel Disclosure: TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit

Abstract Abstract 4876 Background Recent studies have found obesity to be associated with a 1.5- to 2-fold elevated risk of developing multiple myeloma. This is of particular interest given that elevated levels of the pro-inflammatory cytokine interleukin (IL)-6 have been found in obese persons, and, at the same time, IL-6 has well-known proliferative and anti-apoptotic effects on monoclonal plasma-cells. Also insulin-like growth factors (IGFs) have been proposed to play a role since obesity often causes insulin resistance, which in turn modulates the bioavailability of IGF-1 Similar to IL-6, prior studies have found IGF-1 to have both growth and survival effects on monoclonal plasma-cells. Based on these facts, we have speculated that obesity might increase the risk of the multiple myeloma precursor monoclonal gammopathy of undetermined significance (MGUS), or, alternatively, that obesity may increase the risk for transformation from MGUS to multiple myeloma. We conducted the first large screening study designed to assess the association between obesity and MGUS among almost 2,000 African-American and Caucasian women. Methods We included 1000 African-American and 996 Caucasian women (age 40-79, median 48 years) from the Southern Community Cohort Study to assess MGUS risk in relation to obesity. Per our sampling strategy, about 50% of the participants were obese. Medical record-abstracted weight and height (measured on the day of study enrollment) and self-reported values had very high concordance (Pearson correlation >0.95). Serum samples from all subjects were analyzed by electrophoresis performed on agarose gel; samples with a discrete or localized band were subjected to immunofixation. Using logistic regression models, we estimated odds ratios (ORs) as measures of risk. Results Among all study participants, 39 (3.9%) African-Americans and 21 (2.1%) Caucasians were found to have MGUS, yielding a 1.9-fold (95%CI 1.1-2.3; p=0.021) higher risk of MGUS among African-Americans (vs. Caucasians). On multivariate analysis, we found obesity (OR=1.8, 95%CI 1.03-3.1; p=0.039), African-American race (OR=1.8, 95%CI 1.04-3.1; p=0.037), and increasing age (quartiles: ≥55 vs. <43 years) (OR=2.5, 95%CI 1.1-5.7; p=0.028) to be independently associated with an excess risk of MGUS. Another interesting finding was that the distribution of the monoclonal immunoglobulin isotype usage among African-American and Caucasian women was significantly different (p=0.007). Their respective rates were: IgG in 79.5% and 71.3 %; IgA in 7.7% and 0%; IgM in 7.7% and 19%; biclonal in 5.1% and 4.7%; and triclonal in 0% and 4.7%. The distribution of serum light-chain types between the two races was also significantly different (P=0.003, chi-square test): kappa in 53.8% and 47.6%; lambda in 43.6% and 42.8%; biclonal 2.6% and 4.7%; and triclonal in 0% and 4.7%. Conclusions Our finding that MGUS is twice as common among obese (vs. non-obese) women, and independent of race, supports the hypothesis that obesity is etiologically linked to myelomagenesis and may have public health impact. The observed 2-fold excess of MGUS among African-Americans (vs. Caucasians) of similar socio-economic status, coupled with other recent studies supports a role for susceptibility genes as the cause for racial disparity in the prevalence of MGUS. Disclosures No relevant conflicts of interest to declare.