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Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) is a multiorgan syndrome with rare and heterogenous cardiac manifestations. We present the case of a man with pericardial effusion complicated by cardiac tamponade, new onset atrial fibrillation, and high-degree atrioventricular block leading to a diagnosis of POEMS syndrome. (Level of Difficulty: Advanced.), Graphical abstract

The MAF translocations, t(14;16) and t(14;20), are considered as adverse prognostic factors based on few studies with small sample sizes. We report on their prognostic impact in a large group of 254 patients - 223 (87.8%) with t(14;16) and 31 (12.2%) with t(14;20). There were no intergroup differences in survival estimates. Median progression-free survival was 16.6 months for t(14;16) and 24.9 months for t(14;20) (

POEMS syndrome, a rare plasma cell disorder, is challenging both in the diagnostic and therapeutic management. We present real word retrospective analysis of 108 cases analyzing clinical features and therapeutic modes. We compare our results with the available literature. This is the first description with such wide use of proteasome inhibitors in first line treatment. POEMS (Polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes) syndrome is a rare and challenging plasma cell disorder, both in the diagnostic and therapeutic management of the disease. Currently, the literature on POEMS is sparse with most evidence being case reports and small case studies. We present a retrospective real world experience of 108 patients with POEMS. We analyzed the clinical features and therapeutic interventions. Regarding clinical features, our findings demonstrated that skin lesions, thrombocythemia and polycythemia were present less frequently than reported previously. Regarding clinical interventions, this is one of the largest analyses of front line treatment in POEMS and the first one to include frequent utilization of proteasome inhibitors (37%). Bortezomib monotherapy was the most effective therapy achieving complete remission/very good partial remissions (CR/VGPR) in 69% of patients. Thirty percent of patients proceeded to planned autologous stem cell transplant (ASCT) as part of the front-line treatment resulting in statistically superior progression-free (PFS) and overall survival (OS) compared to non-ASCT treated patients (P= .003). In multivariate analysis, anemia, thrombocytopenia, and as age over 60 were associated with a negative impact on patient outcomes.

Background Proteasome inhibitors used in the treatment of multiple myeloma act primarily through the disruption of intrinsic cellular protein quality maintenance, resulting in proteotoxic stress, cellular dysfunction, and, ultimately, cell death. We assessed whether evidence has shown off-target myocardial dysfunction related to the administration of bortezomib-based chemotherapy for multiple myeloma. Patients and Methods Patients aged 18 to 70 years who were free of significant cardiovascular disease were included. They underwent evaluations before and after each dose of bortezomib to assess for clinical, subclinical, and transient cardiotoxicity using echocardiography and serum biomarker measurement. Cardiac magnetic resonance imaging was performed at 3 separately defined intervals. The primary modality for determining subclinical myocardial dysfunction was echocardiographic assessment of the global longitudinal strain (GLS). Results Eleven patients (7 men) with an average age of 55 years were included. No evidence of cumulative myocardial dysfunction was found using echocardiographic markers, primarily GLS (average change in absolute GLS, −1.17; P = .064). Additionally, no echocardiographic evidence of transient cardiotoxicity was found. The left ventricular ejection fraction (LVEF) also did not show any significant changes (ΔLVEF, −2.17%; P = .15). Magnetic resonance imaging confirmed no changes in structure or function (ΔLVEF, −2.6%; P = .54) and extracellular volume fraction (Δ = 2%; P = .46). The serum biomarker levels also did not change significantly over time. Conclusion We did not observe cardiotoxicity from bortezomib-based chemotherapy despite very intensive evaluation with multiple modalities. Neither cumulative nor transient alterations were found in our metrics, suggesting that bortezomib is safe from a cardiovascular standpoint for patients free of cardiovascular disease.

Background DARA is approved across lines of therapy for multiple myeloma (MM). The phase 2 GRIFFIN study (NCT02874742) investigated DARA+RVd (D-RVd) in transplant-eligible NDMM; at the primary analysis, D-RVd improved efficacy, and safety was consistent with prior reports for DARA and RVd. We conducted a post-hoc analysis of GRIFFIN to evaluate anti-thrombosis prophylaxis use, in concordance with IMWG guidelines, and the incidence of VTEs, given a historical risk of VTEs with lenalidomide plus dexamethasone occurring in 10-25% of MM patients (pts). Methods Pts with NDMM eligible for autologous stem cell transplant (ASCT) were randomized 1:1 to receive 4 cycles of D-RVd/RVd induction, high-dose therapy, ASCT, 2 cycles of D-RVd/RVd consolidation, and maintenance with DARA-R/R for 24 months. During induction and consolidation (21-day cycles), pts received R (25 mg PO on Days 1-14); V (1.3 mg/m2 SC on Days 1, 4, 8, 11); and d (40 mg QW). DARA (16 mg/kg IV) was given on Days 1, 8, 15 of Cycles 1-4 and Day 1 of Cycles 5-6. During maintenance (Cycles 7-32; 28-day cycles), pts received R (10 mg PO on Days 1-21; if tolerated, 15 mg in Cycles 10+)±DARA (16 mg/kg IV Q8W or Q4W per protocol amendment 2). VTE prophylaxis was recommended for all pts (aspirin, ≥162 mg) with alternative prophylaxis for pts at increased VTE risk, based on medical history. VTEs were identified through standardized MedDRA queries, and treatment group comparisons were by descriptive analyses. Results VTEs occurred in 10% (10/99) of D-RVd pts and 15% (15/102) of RVd pts. Grade 3/4 VTEs occurred in 4% of D-RVd pts and 6% of RVd pts, with grade 3 pulmonary embolism in 1% of D-RVd pts and 4% of RVd pts. The median (range) time to VTE was 379 (6-810) and 232 (21-511) days in the D-RVd and RVd groups, respectively. Anti-thrombosis prophylaxis use was reported in 83% of D-RVd pts and 83% of RVd pts, including heparin derivates in 14% and 19% of pts, respectively (majority of pts on LMWH). Among pts who developed a VTE, 80% (8/10) of D-RVd pts and 93% (14/15) of RVd pts received anti-thrombosis medication, including LMWH in 30% and 27% of pts, respectively. However, only 60% (6/10) of D-RVd pts and 67% (10/15) of RVd pts were on anti-thrombosis prophylaxis at the time of the VTE, including aspirin in 40% and 60% of pts and LMWH in 10% and 7% of pts, respectively. One D-RVd pt received DOAC (rivaroxaban). Bone marrow involvement ≥60% plasma cells was seen in 50% of D-RVd pts and 60% of RVd pts developing VTEs, compared with 43% of all D-RVd pts and 41% of all RVd pts. Conclusion In this descriptive analysis, the use of daratumumab did not increase the VTE rate, and the median time to VTE was longer for D-RVd. Although no formal conclusion can be drawn, these observations indicate additional and larger investigations may be warranted to understand optimal VTE prophylaxis in NDMM pts, as current data show VTE prophylactic therapy adherence may be suboptimal.

PURPOSE Multiple myeloma (MM) is a genetically heterogeneous malignancy characterized by variable treatment responses. Although numerous drugs have been approved in recent years, the ability to predict treatment response and tailor individual therapy is limited by the absence of robust predictive biomarkers. The goal of this clinical trial was to use ex vivo, high-throughput screening (HTS) of 170 compounds to predict response among patients with relapsed or refractory MM and inform the next treatment decisions. Additionally, we integrated HTS with multi-omic analysis to uncover novel associations between in vitro drug sensitivity and gene expression and mutation profiles. MATERIALS AND METHODS Twenty-five patients with relapsed or refractory MM underwent a screening bone marrow or soft tissue biopsy. Sixteen patients were found to have sufficient plasma cells for HTS. Targeted next-generation sequencing was performed on plasma cell-free DNA from all patients who underwent HTS. RNA and whole-exome sequencing of bone marrow plasma cells were performed on eight and seven patients, respectively. RESULTS Results of HTS testing were made available to treating physicians within a median of 5 days from the biopsy. An actionable treatment result was identified in all 16 patients examined. Among the 13 patients who received assay-guided therapy, 92% achieved stable disease or better. The expression of 105 genes and mutations in 12 genes correlated with in vitro cytotoxicity. CONCLUSION In patients with relapsed or refractory MM, we demonstrate the feasibility of ex vivo drug sensitivity testing on isolated plasma cells from patient bone marrow biopsies or extramedullary plasmacytomas to inform the next line of therapy.

Minimal residual disease (MRD) assessment is incorporated in an increasing number of multiple myeloma (MM) clinical trials as a correlative analysis, an endpoint or even as a determinant of subsequent therapy. There is substantial heterogeneity across clinical trials in how MRD is assessed and reported, creating challenges for data interpretation and for the design of subsequent studies. We convened an international panel of MM investigators to harmonize how MRD should be assessed and reported in MM clinical trials. The panel provides consensus on which MM trials should include MRD, the recommended time points for MRD assessment, and expected analytical validation for MRD assays. We subsequently outlined parameters for reporting MRD results implementing the intention-to-treat principle. The panel provides guidance regarding the incorporation of newer peripheral blood-based and imaging-based approaches to detection of residual disease. Recommendations are summarized in 13 consensus statements that should be followed by sponsors, investigators, editors, and reviewers engaged in designing, performing, and interpreting MM trials.

Objective To report our institutional experience with paraproteinemic neuropathy. Methods We reviewed the charts of patients evaluated at our tertiary, academic neuromuscular clinic for neuropathy between 2017 and 2019 and selected those with a serum monoclonal protein. We collected patients' characteristics and reviewed their initial diagnoses and eventual outcomes. Results Fifty-four of 410 patients with neuropathy (13%) had a monoclonal protein. Of these patients, 25% had not had SPEP or IFE checked prior to referral. FLC was not checked in any of the patients prior to referral. The neuropathy was felt to be related to the monoclonal protein in 24 patients (44%). Ten patients (19%), had been misdiagnosed either because they were not screened for monoclonal protein or the monoclonal protein was considered a MGUS. AL amyloid and POEMS syndrome were the most frequently missed diagnoses. Conclusion The diagnosis of paraproteinemic neuropathy was missed in nearly one in five patients in our cohort. Failure to accurately characterize a paraproteinemic neuropathy can have devastating effect on patients as some have underlying malignancies. We propose that testing serum free light chains in patients with peripheral neuropathy of unknow etiology, when SPEP/IFE are normal, may reduce the rate of misdiagnosis. Furthermore, patients with refractory CIDP should be carefully screened for POEMS syndrome.

Lenalidomide, bortezomib, and dexamethasone (RVd) followed by autologous stem cell transplantation (ASCT) is standard frontline therapy for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab (D) to RVd (D-RVd) in transplant-eligible NDMM patients was evaluated. Patients (N = 207) were randomized 1:1 to D-RVd or RVd induction (4 cycles), ASCT, D-RVd or RVd consolidation (2 cycles), and lenalidomide or lenalidomide plus D maintenance (26 cycles). The primary end point, stringent complete response (sCR) rate by the end of post-ASCT consolidation, favored D-RVd vs RVd (42.4% vs 32.0%; odds ratio, 1.57; 95% confidence interval, 0.87-2.82; 1-sided P = .068) and met the prespecified 1-sided α of 0.10. With longer follow-up (median, 22.1 months), responses deepened; sCR rates improved for D-RVd vs RVd (62.6% vs 45.4%; P = .0177), as did minimal residual disease (MRD) negativity (10−5 threshold) rates in the intent-to-treat population (51.0% vs 20.4%; P < .0001). Four patients (3.8%) in the D-RVd group and 7 patients (6.8%) in the RVd group progressed; respective 24-month progression-free survival rates were 95.8% and 89.8%. Grade 3/4 hematologic adverse events were more common with D-RVd. More infections occurred with D-RVd, but grade 3/4 infection rates were similar. Median CD34+ cell yield was 8.2 × 106/kg for D-RVd and 9.4 × 106/kg for RVd, although plerixafor use was more common with D-RVd. Median times to neutrophil and platelet engraftment were comparable. Daratumumab with RVd induction and consolidation improved depth of response in patients with transplant-eligible NDMM, with no new safety concerns. This trial was registered at www.clinicaltrials.gov as #NCT02874742.

Introduction: DARA is approved across lines of therapy for multiple myeloma, including in combination with standard-of-care regimens for NDMM. The CXCR4 receptor antagonist plerixafor is used in conjunction with granulocyte colony-stimulating factor (G-CSF) to increase stem cell mobilization for autologous stem cell transplant (ASCT) and can be given by upfront decision or as a rescue strategy. The phase 2 randomized GRIFFIN study (NCT02874742) evaluates frontline DARA in combination with lenalidomide, bortezomib, and dexamethasone (D-RVd) in transplant-eligible NDMM. In the primary analysis, more pts undergoing stem cell mobilization/collection in the D-RVd group received plerixafor compared with the RVd group (69.5% [66/95] vs 56.3% [45/80]) (Voorhees PM, et al. Blood. 2020). The phase 2 MASTER study (NCT03224507) evaluates DARA plus carfilzomib, lenalidomide, and dexamethasone (D-KRd) in transplant-eligible NDMM (Costa LJ, et al. EHA Library. 2020). Here, we present a summary of stem cell mobilization, collection yields, and ASCT data following frontline DARA-based induction therapy in GRIFFIN and MASTER. Methods: Eligible pts had NDMM and were candidates for ASCT. In GRIFFIN, pts were randomized 1:1 to receive D-RVd or RVd. Pts received 4 induction cycles (21 days) of lenalidomide (R; 25 mg PO on Days 1-14), bortezomib (1.3 mg/m 2 SC on Days 1, 4, 8, and 11), and dexamethasone (d; 40 mg PO QW) ± DARA (16 mg/kg IV QW in Cycles 1-4). After Cycle 4, pts underwent stem cell mobilization with G-CSF ± plerixafor, per institutional standards; if unsuccessful, chemo mobilization was permitted. Pts then received ASCT and subsequently 2 consolidation cycles (21 days) of D-RVd or RVd followed by maintenance therapy with R ± DARA. In the single-arm MASTER study, pts received 4 D-KRd induction cycles, ASCT, and 0, 4 or 8 D-KRd consolidation cycles followed by maintenance therapy with R, based upon achievement of minimal residual disease-negativity. In each 28-day cycle, all pts received carfilzomib (20/56 mg/m 2 IV QW), R (25 mg PO on Days 1-21), d (40 mg PO or IV QW), and DARA (16 mg/kg IV QW for Cycles 1-2, Q2W for Cycles 3-6, and Q4W for Cycles 7+). Mobilization was with G-CSF ± plerixafor as per institutional standards. Results: In GRIFFIN, among 207 (D-RVd, n=104; RVd, n=103) randomized pts, 91.3% (n=95) of D-RVd pts and 77.7% (n=80) of RVd pts underwent stem cell mobilization; of those mobilized, 98.9% (n=94) and 97.5% (n=78) underwent ASCT, respectively. In MASTER, 123 D-KRd pts enrolled and at last follow-up, 91.1% (n=112) underwent stem cell mobilization; of those mobilized, 98.2% (n=110) completed ASCT. In GRIFFIN, 46.3% (n=81) of mobilized pts received plerixafor upfront (D-RVd, 51.6%, n=49; RVd, 40.0%, n=32), and 18.3% (n=32 pts) received rescue plerixafor (D-RVd, 20.0%, n=19; RVd, 16.3%, n=13). In MASTER, 70.5% (n=79) D-KRd pts received upfront plerixafor and 25.9% (n=29) received rescue plerixafor. Median CD34 + cell yield was 8.3 × 10 6/kg for D-RVd and 9.4 ×10 6/kg for RVd in GRIFFIN, 6.0 ×10 6/kg for D-KRd in MASTER, and was numerically higher for pts who received upfront plerixafor. Median days for stem cell collection was 1 for pts receiving RVd and 2 for those receiving D-RVd or D-KRd. Median transplanted CD34 + cell count was 4.2 ×10 6/kg for D-RVd and 4.8 ×10 6/kg for RVd in GRIFFIN, and 3.2 ×10 6/kg for D-KRd in MASTER. In GRIFFIN, 93.7% of D-RVd pts and 98.8% of RVd pts reached the minimum institutional CD34 + threshold to perform a single ASCT, which was comparable to results in MASTER (95.5% of D-KRd pts) after first mobilization attempt; 85.3% of D-RVd pts, 92.5% of RVd pts, and 79.5% of D-KRd pts collected 2 times the minimum threshold of stem cells. Additional data by upfront and rescue plerixafor strategies are shown in the Table. Conclusion: The addition of DARA to proteasome inhibitor/immunomodulatory drug/dexamethasone-based induction therapy has a modest impact on stem cell mobilization, with a lower yield of stem cells and higher median number of days required for collection. Nonetheless, pts were able to undergo transplantation, and most pts collected sufficient stem cells for 2 transplants. Pts who received plerixafor by an upfront decision had numerically higher stem cell yields than pts who received plerixafor by a rescue strategy. An upfront plerixafor strategy for pts receiving DARA-based quadruplet induction therapy should be considered with allowance for additional days of apheresis as needed. Figure 1 Figure 1. Disclosures Chhabra: GSK: Honoraria. Costa: Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Kaufman: BMS: Consultancy, Research Funding; Fortis Therapeutics: Research Funding; Roche/Genetech, Tecnopharma: Consultancy, Honoraria; Sutro, Takeda: Research Funding; Genentech, AbbVie, Janssen: Consultancy, Research Funding; Novartis: Research Funding; Incyte, celgene: Consultancy; Tecnofarma SAS, AbbVie: Honoraria; Janssen: Honoraria; Incyte, TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Heidelberg Pharma: Research Funding; Amgen: Research Funding. Sborov: Sanofi: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; SkylineDx: Consultancy; GlaxoSmithKline: Consultancy. Reeves: Incyte Corporation: Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Speakers Bureau; Pharma Essentia: Consultancy, Honoraria. Rodriguez: Karyopharm: Consultancy, Speakers Bureau; Oncopeptides: Consultancy, Honoraria; Amgen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau. Chari: Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shattuck Labs: Consultancy, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: 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; Millenium/Takeda: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding. Silbermann: Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Shah: Sutro Biopharma: Research Funding; Janssen: Research Funding; Indapta Therapeutics: Consultancy; CareDx: Consultancy; Sanofi: Consultancy; Kite: Consultancy; Poseida: Research Funding; Amgen: Consultancy; BMS/Celgene: Research Funding; Bluebird Bio: Research Funding; CSL Behring: Consultancy; GSK: Consultancy; Precision Biosciences: Research Funding; Teneobio: Research Funding; Oncopeptides: Consultancy; Nektar: Research Funding; Karyopharm: Consultancy. Bumma: Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees. Holstein: Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech, GSK, Janssen, Secura Bio, Sorrento: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jakubowiak: BMS: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gracell: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; GSK: 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. Wildes: Carevive: Consultancy; Seattle Genetics: Consultancy; Sanofi: Consultancy; Janssen: Consultancy. Orlowski: CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Other: Clinical research funding; Asylia Therapeutics, Inc., BioTheryX, Inc., and Heidelberg Pharma, AG.: Other: Laboratory research funding; Asylia Therapeutics, Inc.: Current holder of individual stocks in a privately-held company, Patents & Royalties; Amgen, Inc., BioTheryX, Inc., Bristol-Myers Squibb, Celgene, Forma Therapeutics, Genzyme, GSK Biologicals, Janssen Biotech, Juno Therapeutics, Karyopharm Therapeutics, Inc., Kite Pharma, Neoleukin Corporation, Oncopeptides AB, Regeneron Pharmaceuticals, I: Membership on an entity's Board of Directors or advisory committees; Amgen, Inc., BioTheryX, Inc., Bristol-Myers Squibb, Celgene, EcoR1 Capital LLC, Genzyme, GSK Biologicals, Janssen Biotech, Karyopharm Therapeutics, Inc., Neoleukin Corporation, Oncopeptides AB, Regeneron Pharmaceuticals, Inc., Sanofi-Aventis, and Takeda P: Consultancy, Honoraria. Shain: Novartis Pharmaceuticals Corporation: Consultancy; Karyopharm Therapeutics Inc.: Honoraria, Research Funding; Janssen oncology: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi Genzyme: Consultancy, Speakers Bureau; GlaxoSmithLine, LLC: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies Corporation: Consultancy, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Cowan: Janssen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Cellectar: Consultancy; Harpoon: Research Funding; GSK: Consultancy; Secura Bio: Consultancy; BMS: Research Funding; Nektar: Research Funding. Dholaria: Takeda: Research Funding; Jazz: Speakers Bureau; MEI: Research Funding; Angiocrine: Research Funding; Poseida: Research Funding; Celgene: Speakers Bureau; Pfizer: Research Funding; Janssen: Research Funding. Pei: Janssen: Current Employment, Current equity holder in publicly-traded company. Cortoos: Janssen: Current Employment, Current equity holder in publicly-traded company. Patel: Janssen: Current Employment. Bartlett: Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company. Lin: Janssen: Current Employment. Richardson: AstraZeneca: Consultancy; Regeneron: Consultancy; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; AbbVie: Consultancy; GlaxoSmithKline: Consultancy; Karyopharm: Consultancy, Research Funding; Protocol Intelligence: Consultancy; Janssen: Consultancy; Sanofi: Consultancy; Secura Bio: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding. Voorhees: Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, 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; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The specific regimen combination is not yet approved, but individual components are.

Background Daratumumab, when combined with PI or an IMiD increases depth of response in MM. Minimal/measurable residual disease (MRD) is an important prognostic factor for long term outcome in patients (pts) with newly diagnosed MM (NDMM), but has not been used to modify therapy. We treated NDMM pts with daratumumab, carfilzomib, lenalidomide and dexamethasone (Dara-KRd) and employed MRD by next generation sequencing (NGS) to guide the use and duration of Dara-KRd post-autologous transplant (AHCT) and treatment cessation in pts with confirmed MRD negativity. Methods We enrolled pts with NDMM, CrCl ≥40 ml/min, adequate organ function, ECOG performance status 0-2 with no age limit. There was a planned enrichment for pts with high-risk cytogenetic abnormalities (HRCA). Treatment cycles consisted of daratumumab 16 mg/kg IV days 1,8,15,22 (typical reduction in frequency with subsequent cycles), carfilzomib 56 mg/m2 IV days 1,8,15, lenalidomide 25 mg days 1-21 and dexamethasone 40 mg oral/IV days 1,8,15,22 repeated every 28 days. Pts received 4 cycles of Dara-KRd induction, AHCT, and received 0, 4 or 8 cycles of Dara-KRd consolidation, according to MRD status. MRD was evaluated by NGS (ClonoSEQ®) in all pts at end of induction, post-AHCT, and during each 4-cycle block of Dara-KRd consolidation. Primary endpoint was achievement of MRD negativity ( Results Among 123 participants, 46 (37%) had 1 and 24 (20%) had 2+ HRCA [gain 1q, t(4;14), t(14;16), t(14;20) or del(17p)]. Median age was 60 y (36-79), 20% had ECOG 2, 21% had high LDH, and 20% R-ISS3. Disease was trackable by NGS-MRD in 96% of pts. Median follow up is 25.1 mo. Most common severe adverse events were pneumonia (N=8), and venous thromboembolism (N=3). Overall, 80% of pts have achieved MRD negativity (78%, 82% and 79% of pts with 0, 1 and 2+ HRCA respectively) and 65% MRD Conclusion Monoclonal antibody-based quadruplet therapy, AHCT and MRD response-adapted consolidation therapy leads to high rate of MRD negativity in NDMM. For most patients with NDMM, MRD-directed adaptive treatment offers the prospect of confirmed deep responses and investigation of MRD surveillance as an alternative to indefinite maintenance.

Introduction: DARA, a human IgGκ monoclonal antibody targeting CD38, is approved as monotherapy and in combination with standard-of-care regimens for relapsed/refractory multiple myeloma and NDMM. In the primary analysis of the phase 2 GRIFFIN study (NCT02874742) in patients with transplant-eligible NDMM, DARA plus RVd (D-RVd) significantly improved rates of stringent complete response (sCR) by the end of post-transplant consolidation therapy versus RVd (Voorhees P, Blood 2020). Here, we present updated efficacy and safety results following 12 months of maintenance therapy with lenalidomide (R) or DARA plus R (D-R). Methods: Patients with NDMM eligible for high-dose therapy (HDT) and autologous stem cell transplant (ASCT) were randomized 1:1 to RVd ± DARA, stratified by ISS stage and creatinine clearance rate. Patients received 4 induction cycles, HDT, ASCT, 2 consolidation cycles, and maintenance with R ± DARA for 24 months. During induction and consolidation, patients received R 25 mg PO on Days 1-14; V 1.3 mg/m2 SC on Days 1, 4, 8, and 11; and d 40 mg QW every 21 days. DARA 16 mg/kg IV was given on Days 1, 8, and 15 of Cycles 1-4 and Day 1 of Cycles 5-6. During maintenance (Cycles 7-32), patients received R 10 mg (15 mg in Cycles 10+ if tolerated) on Days 1-21 every 28 days ± DARA 16 mg/kg IV Q8W (or Q4W per patient decision after Amendment 2). The primary endpoint was rate of sCR at the end of post-ASCT consolidation per IMWG criteria, evaluated by a validated computer algorithm. Key secondary endpoints included progression-free survival (PFS) and rate of minimal residual disease (MRD) negativity (10-5 threshold per IMWG criteria) assessed by next-generation sequencing (clonoSEQ; Adaptive Biotechnologies). The primary hypothesis was tested at a 1-sided alpha of 0.10. All secondary analyses were evaluated using a 2-sided P value (alpha 0.05) and were not adjusted for multiplicity. Results: In total, 207 patients were randomized (D-RVd, n=104; RVd, n=103). Baseline demographics and disease characteristics were well balanced between arms. At the end of post-transplant consolidation (median follow-up, 13.5 months) in the response-evaluable population, the sCR rate favored D-RVd versus RVd (42.4% [42/99] vs 32.0% [31/97]; 1-sided P=0.0680). With additional D-R or R maintenance therapy, responses continued to deepen and remained higher for the D-RVd group versus the RVd group. At the 12-months-of-maintenance therapy data cut (median follow-up, 26.7 months), the sCR rate still favored D-RVd versus RVd (63.6% [63/99] vs 47.4% [46/97], 2-sided P=0.0253; Figure). MRD-negativity (10‒5) rates in the ITT population favored D-RVd versus RVd (62.5% [65/104] vs 27.2% [28/103], P Conclusions: After 26.7 months of median follow-up, the addition of DARA to RVd induction and consolidation, followed by D-R maintenance in patients with transplant-eligible NDMM continued to demonstrate deep and improved responses, including higher sCR and MRD negativity rates, compared with lenalidomide alone. Maintenance therapy increased sCR and MRD negativity rates, compared to post-consolidation rates. No new safety concerns were observed with longer follow-up. Support: Alliance Foundation Trials; https://acknowledgments.alliancefound.org; Janssen Oncology Disclosures Kaufman: Tecnopharma: Consultancy, Honoraria; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria; Sanofi/Genyzme: Consultancy, Honoraria; AbbVie: Consultancy; Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees. Sborov:University of Utah: Current Employment; Celgene, Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Reeves:Incyte: Honoraria; Takeda: Honoraria; Bristol Myers Squibb: Speakers Bureau. Rodriguez:BMS, Takeda, Amgen: Consultancy, Speakers Bureau. Chari:Janssen, Celgene, Novartis, Amgen, Bristol-Myers Squibb, Karyopharm, Sanofi, Genzyme, Seattle Genetics, Oncopeptides, Millennium/Takeda, Antengene, Glaxo Smith Kline, Secura Bio: Consultancy; Janssen, Celgene, Novartis, Amgen, Pharmacyclics, Seattle Genetics, Millennium/Takeda: Research Funding. Silbermann:Karyopharm: Consultancy; Janssen: Consultancy; Sanofi-Aventis: Consultancy, Research Funding. Costa:AbbVie: Consultancy; Sanofi: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Genentech: Consultancy; BMS: Consultancy, Honoraria. Anderson:Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Efebera:Pharmacyclics: Research Funding; Ohio State University: Current Employment; Celgene: Research Funding; Takeda: Honoraria, Speakers Bureau. Holstein:Sorrento: Consultancy; Adaptive Biotechnologies: Consultancy; Takeda: Consultancy; GSK: Consultancy; Celgene: Consultancy; Genentech: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy, Research Funding. Costello:Takeda, Celgene: Consultancy, Honoraria. Jakubowiak:Adaptive, Juno: Consultancy, Honoraria; AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Wildes:Seattle Genetics: Consultancy; Carevive Systems: Consultancy; Janssen: Research Funding. Orlowski:Founder of Asylia Therapeutics, Inc., with associated patents and an equity interest, though this technology does not bear on the current submission.: Current equity holder in private company, Patents & Royalties; STATinMED Research: Consultancy; Sanofi-Aventis, Servier, Takeda Pharmaceuticals North America, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen, Inc., AstraZeneca, BMS, Celgene, EcoR1 Capital LLC, Forma Therapeutics, Genzyme, GSK Biologicals, Ionis Pharmaceuticals, Inc., Janssen Biotech, Juno Therapeutics, Kite Pharma, Legend Biotech USA, Molecular Partners, Regeneron Pharmaceuticals, Inc.,: Honoraria, Membership on an entity's Board of Directors or advisory committees; Laboratory research funding from BioTheryX, and clinical research funding from CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Research Funding. Shain:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; AbbVie: Research Funding; GlaxoSmithKline: Speakers Bureau; Adaptive: Consultancy, Honoraria; Sanofi/Genzyme: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Karyopharm: Research Funding, Speakers Bureau; Amgen: Speakers Bureau. Cowan:Nektar: Research Funding; Janssen: Consultancy, Research Funding; Abbvie: Research Funding; Bristol-Myer Squibb: Research Funding; Celgene: Consultancy, Research Funding; Cellectar: Consultancy; Sanofi-Aventis: Consultancy. Lutska:Janssen: Current Employment. Bobba:Janssen: Current Employment. Pei:Janssen: Current Employment, Current equity holder in publicly-traded company. Ukropec:Janssen: Current Employment, Current equity holder in publicly-traded company. Vermeulen:Janssen: Current Employment, Current equity holder in publicly-traded company. Lin:Janssen Scientific Affairs: Current Employment, Current equity holder in publicly-traded company. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Voorhees:TeneoBio: Other: Advisory Board; Oncopeptides: Consultancy, Honoraria; Novartis: Consultancy; Janssen: Other: Advisory Board; GSK: Honoraria; BMS: Other: Advisory Board; Adaptive Biotechnologies: Other: Advisory Board. OffLabel Disclosure: The specific regimen combination is not yet approved, but individual components are.

The t(14;16) translocation, found in 3%-5% of newly diagnosed (ND) multiple myeloma (MM), has been associated with adverse outcomes. However, the studies establishing the characteristics of t(14;16) included solely small cohorts. The goal of the current international, multicenter (n = 25 centers), retrospective study was to describe the characteristics and outcomes of t(14;16) patients in a large, real-world cohort (n = 223). A substantial fraction of patients had renal impairment (24%) and hemoglobin10 g/dL (56%) on initial presentation. Combined therapy of both immunomodulatory drug and proteasome inhibitor (PI) in the first line was used in 35% of patients. Autologous stem cell transplantation was performed in 42% of patients. With a median follow up of 4.1 years (95% CI 3.7-18.7), the median progression-free survival (PFS) and overall survival (OS) from first line therapy were 2.1 years (95% CI 1.5-2.4) and 4.1 years (95% CI 3.3-5.5), respectively. Worse OS was predicted by age 60 years (HR = 1.65, 95% CI [1.05-2.58]), as well as revised International Scoring System (R-ISS) 3 (vs R-ISS 2; HR = 2.59, 95% CI [1.59-4.24]). In conclusion, based on the largest reported cohort of t(14;16) patients, quarter of this subset of MM patients initially presents with renal failure, while older age and the R-ISS 3 predict poor survival.

Recent significant advances in the treatment of multiple myeloma have resulted in an improvement in median overall survival from 4.6 years, for patients diagnosed between 2001 and 2005, to 6.1 years, for those diagnosed between 2006 and 2010 (Kumar et al., 2014). However, myeloma bone lesions persist in the absence of active disease and continue to be frequent and significant causes of patient morbidity and contribute to mortality. While bisphosphonate therapy in combination with anti-myeloma therapy remains the cornerstone of skeletal disease management in myeloma, open questions regarding the optimal management of patients with myeloma bone disease remain. This article will address when to initiate and stop bone-targeted therapy in patients with monoclonal gammopathies, duration of bisphosphonate treatment in the era of more effective anti-myeloma treatment, the role of bone resorption markers in determining the dosing schedule for anti-resorptive therapy, risks and benefits of long term anti-resorptive therapy, and whether anti-resorptive therapies should be stopped to enhance the potential anabolic effects of proteasome antagonists and other anabolic agents. J. Cell. Physiol. 231: 2374-2379, 2016. © 2016 Wiley Periodicals, Inc.

8539 Background: TAK-079 is a subcutaneously (SC) administered mAb with multiple modes of action for killing target cells. Here we report data from an ongoing dose finding study of TAK-079 monotherapy in patients with RRMM (NCT03439280). Methods: Pt were eligible after ≥ 3 lines of therapy and previous exposure to immunomodulatory drug (IMiD), proteasome inhibitor (PI), alkylating agent, and corticosteroid; prior anti-CD38 therapy allowed. Patients were refractory or intolerant to at least 1 PI and 1 IMiD. TAK-079 given as a SC injection weekly for 8 doses, every other week for 8 doses, then monthly until disease progression (PD) or unacceptable toxicity. SC injection was 2 mL administered in ≤ 1 minute. Results: 34 patients were enrolled across 5 fixed dose cohorts (TAK-079 45-135-300-600-1200 mg SC) as of 09 December 2019. Median age was 65 (50–81) years. At study entry, 65% were refractory to both an IMiD and PI; 82% refractory to last line of therapy, 21% of patients were previously exposed to at least 1 anti-CD38 monoclonal antibody. Median number of prior therapies was 4 (2,12). No ≥ Grade 1 early or late systemic infusion reactions (IRR) reported. Three ( < 1%) injection site reactions described in > 1200 injections administered; 2 mild pruritis and 1 moderate swelling. Drug related adverse events (AEs), any grade, occurring in at least 10% of patients were: fatigue (21%), anemia (18%), neutropenia (18%), leukopenia (15%). Neutropenia was the only drug related grade 3 AEs in 2 or more patients (n = 2); only drug related SAE was 1 Grade 3 diverticulitis. No drug-related grade 4 AEs, AEs leading to study discontinuation, or on-study deaths reported. Recommended phase 2 dose (RP2) is to be 600 mg based on no reported DLTs, no MTD identified, and preliminary efficacy (PFS and response [ORR]). At the RP2 dose, 9 patients received at least 6 cycles of therapy by the data cutoff; their ORR was 33%, median duration of response was not estimable. The clinical benefit rate (minimal response or better) in all 12 patients enrolled at the RP2 dose was 67%. At a median follow-up of 7.5 months, PFS not estimable at the RP2 dose. Conclusions: TAK-079 monotherapy is safe, generally well tolerated, and active in patients with RRMM through tested doses. Clinical activity occurred early and was durable. With no MTD identified, no IRRs, no significant hematologic toxicity, the RP2 dose is 600 mg. PFS, with a median FU of 7.5 months at the data-cut off, is not estimable at the RP2 dose. Updated safety and efficacy data will be presented. Clinical trial information: NCT03439280 .

Introduction Unprecedented depth of response is obtained with regimens incorporating monoclonal antibodies in the management of newly diagnosed multiple myeloma (NDMM). The incremental benefit of AHCT in this setting is being reconsidered but can be appraised by systematic assessment of disease burden pre- and post-AHCT utilizing NGS MRD. Methods We performed a multi-center clinical trial with Dara-KRd induction, AHCT (Melphalan conditioning), and post-AHCT, MRD response-adapted Dara-KRd consolidation. Primary endpoint was MRD Results To date, 82 patients have been enrolled, and 77 (94%) have disease trackable by NGS. Of those, 54 have completed post-induction and 29 post-AHCT assessment. The median age of the cohort is 61 years (range 36-79), with 46% females, 31% with high-risk FISH abnormality [t(4;14) or t(14;16) or del17p] and 20.3% ISS III disease. All patients obtained objective responses with the rate of best responses ≥VGPR of 93% after induction and 100% after AHCT and rate of sCR of 46% and 79%, respectively. MRD responses are displayed in Figure 1a. Patients with MRD Conclusion While a subset of patients with NDMM receiving Dara-KRD achieved MRD negativity after four cycles of induction, subsequent AHCT significantly increased the number of patients obtaining this status. Despite a quadruple induction regimen utilizing what are considered the most effective anti-myeloma drugs, AHCT resulted in a substantial reduction of disease burden in a majority of patients and should remain part of current therapy for fit, NDMM patients. Future trial designs with the intent to defer AHCT for patients may need to demonstrate high rates of MRD negativity to show benefit ultimately.

Multiple myeloma (MM), a malignancy of mature plasma cells, is the second most common hematologic malignancy and the most frequent cancer to involve the skeleton (1, 2). Bone disease in MM patients is characterized by lytic bone lesions that can result in pathologic fractures and severe pain. While recent advances in MM therapy have significantly increased the median survival of newly diagnosed patients (3), skeletal lesions and their sequelae continue to be a major source of patient morbidity and mortality and bone pain is the most frequent presenting symptom of MM patients (4). Rapid improvements in imaging technology now allow physicians to identify ever smaller skeletal and bone marrow abnormalities, however the clinical value of subtle radiographic findings is not always clear. This review summarizes currently available technologies for assessing MM bone disease and provides guidance for how to choose between imaging modalities.

Introduction: DARA, a human IgGκ monoclonal antibody targeting CD38, is approved as monotherapy and in combination with standard-of-care (SoC) regimens for multiple myeloma (MM). In randomized studies, DARA-based regimens significantly improved response rates, depth of response including minimal residual disease (MRD) negativity, and progression-free survival (PFS) in NDMM and relapsed/refractory MM pts. RVd followed by high-dose therapy (HDT), autologous stem cell transplant (ASCT), and consolidation is a SoC regimen for US pts with NDMM. This phase 2, randomized study (GRIFFIN; NCT02874742) evaluated DARA plus RVd (D-RVd) in ASCT-eligible NDMM pts. A 16-pt safety run-in showed no safety concerns. Here, we present results that adding DARA to RVd improves responses rapidly, including depth of response, which increases with longer duration of therapy. Methods: Pts were randomized 1:1 to RVd ± DARA, stratified by ISS stage and creatinine clearance. Pts received 4 induction cycles, HDT, ASCT, 2 consolidation cycles, and maintenance with R ± DARA for 24 mo. During induction and consolidation (Cycles 1-6), pts received R 25 mg PO on Days 1-14; V 1.3 mg/m2 SC on Days 1, 4, 8, and 11; and d 40 mg QW every 21 days. DARA 16 mg/kg IV was given on Days 1, 8, and 15 of Cycles 1-4 and Day 1 of Cycles 5-6. During maintenance (Cycles 7-32), pts received R 10 mg (15 mg in Cycles 10+ if tolerated) on Days 1-21 every 28 days ± DARA 16 mg/kg IV Q8W (or Q4W per pt decision after Amendment 2). The primary endpoint was the stringent complete response (sCR) rate by the end of consolidation per IMWG computer algorithm. The study had 80% power to detect a 15% improvement with a 1-sided alpha of 0.1 (equivalent to 2-sided alpha of 0.2). MRD (10-5 per IMWG criteria) was assessed by next-generation sequencing (clonoSEQ; Adaptive Biotechnologies). Results: A total of 207 pts (D-RVd n = 104; RVd n =103) were randomized. Baseline demographics and disease characteristics were well balanced between arms. Median age was 60 yrs; 48%, 37%, and 14% of pts were ISS stage I, II, or III, respectively; 30 (15%) pts had high cytogenetic risk defined by FISH for del(17p), t(4;14), or t(14;16). The study met its primary endpoint; D-RVd improved the sCR rate by the end of consolidation (42.4% vs 32.0%; odds ratio 1.57; 95% CI, 0.87-2.82; 2-sided P = 0.1359); at the pre-set 2-sided alpha of 0.2. This improvement was observed in all pt subgroups except for the small subsets of ISS stage III or high-cytogenetic risk pts. Responses deepened over time (Figure); the sCR rate was 12% vs 7% with D-RVd vs RVd at the end of induction, increasing to 21% vs 14% after ASCT, and 50% vs 37% at the clinical cutoff (CCO; 13.5 mo median follow-up). D-RVd achieved higher overall response (99% vs 92%), ≥VGPR (91% vs 73%), and ≥CR (52% vs 42%) rates vs RVd by the end of consolidation. At the end of induction, 8/19 (42%) pts achieving ≥CR with D-RVd were MRD negative, compared to 1/13 (8%) pts achieving ≥CR with RVd. At the end of consolidation, 30/51 (59%) pts achieving ≥CR with D-RVd were MRD negative vs 10/41 (24%) pts achieving ≥CR with RVd. Due to the short median follow-up at CCO, PFS and OS were immature, with 6 PFS events in each arm. Median stem cell yield was 8.1 vs 9.4 × 106 cells/kg for D-RVd vs RVd. Median (range) time to platelet engraftment was 13 (2-31) and 12 (1-23) days for D-RVd vs RVd; median (range) time to neutrophil engraftment was 12 (3-31) and 12 (2-23) days for D-RVd vs RVd. Grade 3/4 TEAEs (≥10%) with D-RVd vs RVd included neutropenia (32% vs 15%), lymphopenia (23% vs 23%), thrombocytopenia (16% vs 8%), and leukopenia (15% vs 7%). There was no difference in the rate of grade 3/4 infections between arms. IRRs occurred in 41% of DARA-treated pts, which were primarily grade 1-2. Updated data will be presented. Conclusions: These data demonstrate that adding DARA to RVd significantly improves response rates and depth of response, including sCR and MRD negativity. As seen in other randomized studies, continued use of daratumumab improved depth of response. The overall safety profile of D-RVd is consistent with previous reports with DARA plus SoC. Likewise, similar to what was reported from CASSIOPEIA, stem cell mobilization and ASCT are feasible with D-RVd, without a significant effect on hematopoietic reconstitution. The study is ongoing, with pts continuing maintenance therapy. Disclosures Voorhees: BMS: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GSK: Research Funding; Novartis: Consultancy; Oncopeptides: Consultancy; Takeda: Honoraria, Research Funding; TeneBio: Honoraria, Research Funding; Adaptive Biotechnologies: Honoraria. Kaufman:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Winship Cancer Institute of Emory University: Employment; Takeda: Consultancy; Janssen: Honoraria; Bristol-Myers Squibb: Consultancy; Incyte: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy; AbbVie: Consultancy; Amgen: Consultancy. Sborov:Celgene: Honoraria; Janssen: Consultancy. Reeves:Celgene: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria. Rodriguez:Takeda, Amgen: Consultancy, Speakers Bureau. Chari:Janssen, Celgene, Novartis Pharmaceuticals, Amgen, Bristol Myers Squibb, Pharmacyclics, Karyopharm, Sanofi, Seattle Genetics, OncoPeptides, Millenium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Silbermann:Janssen, Sanofi: Other: Consultant/Advisor. Costa:Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy; Karyopharm: Consultancy; Fujimoto Pharmaceutical Corporation Japan: Other: Advisor. Anderson:Amgen, Janssen, Takeda, Celgene: Consultancy, Speakers Bureau. Shah:Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nkarta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees; Teneobio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene, Janssen, Bluebird Bio, Sutro Biopharma: Research Funding; Poseida: Research Funding; Indapta Therapeutics: Equity Ownership; University of California, San Francisco: Employment; Genentech, Seattle Genetics, Oncopeptides, Karoypharm, Surface Oncology, Precision biosciences GSK, Nektar, Amgen, Indapta Therapeutics, Sanofi: Membership on an entity's Board of Directors or advisory committees. Efebera:Takeda: Honoraria; Akcea: Other: Advisory board, Speakers Bureau; Janssen: Speakers Bureau. Costello:Takeda: Honoraria, Research Funding; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Jakubowiak:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, 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; KaryoPharm Therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SkyLineDx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Wildes:Carevive: Consultancy; Janssen: Research Funding. Orlowski:BioTheryX, Spectrum Pharma: Research Funding; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: 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; Kita Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ionis Pharmaceuticals; Legend Biotech; Molecular Partners; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Sanofi-Aventis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Shain:Celgene: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Cowan:Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Abbvie: Research Funding; Juno: Research Funding; Sanofi: Consultancy; Cellectar: Consultancy. Murphy:Janssen: Employment, Equity Ownership. Lutska:Janssen: Employment. Pei:Janssen: Employment, Equity Ownership. Ukropec:Janssen: Employment, Equity Ownership. Vermeulen:Janssen R&D, LLC: Employment, Equity Ownership. de Boer:Janssen: Employment, Equity Ownership. Hoehn:Janssen: Employment, Equity Ownership. Lin:Janssen: Employment, Equity Ownership. Richardson:Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; 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; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding. OffLabel Disclosure: D-RVd is being investigated in transplant-eligible NDMM

Background: TAK-079 is a subcutaneously (SC) administered, mAb which exhibits more selective binding to human CD38 protein expressed by myeloma cells and less cross reactivity with the CD38 antigen present on red blood cells and platelets. It depletes myeloma cells via apoptosis antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and antibody-dependent cellular phagocytosis (ADCP). TAK-079 was safe and well-tolerated in a first in human study in healthy subjects with potent pharmacodynamic activity when administered as a SC injection (Fedyk et al ASH 2018; abstract 3249). Methods: A multicenter phase 1 study (NCT03439280) evaluating safety, pharmacokinetic (PK), pharmacodynamics, and efficacy of TAK-079 in patients with heavily pretreated RRMM was initiated. Pt with RRMM were eligible after at least 3 lines of therapy and previous exposure to immunomodulatory drug (IMiD), proteasome inhibitor (PI), alkylating agent, and corticosteroid with or without an anti-CD38 or SLAMF7 antibody. Patients were refractory or intolerant to at least 1 PI and 1 IMiD. Ph 1 dose escalation proceeded using a 3+3 design. The TAK-079 dose was given as a SC injection weekly for 8 doses, every other week for 8 doses, then monthly until disease progression (PD) or unacceptable toxicity. Results: 31 patients have been enrolled across 4 dose cohorts (TAK-079 45-135-300-600 mg fixed dose SC); data is available on 28 patients as of the 14 June 2019 data cutoff. Median age was 65 (53-81) years. ISS stage at study entry was I/II/III/missing in 42%, 32%, 19%, 6% of patients respectively, 94% of patients were refractory to either a PI or IMiD and 61% were refractory to both, 23% of patients were previously exposed to at least 1 anti-CD38 monoclonal antibody; 84% had a prior stem cell transplant. The maximum volume of a SC injection was 2 mL, resulting in an administration duration of ≤ 1 minute. No ≥ Grade 1 early or late systemic infusion reactions have been reported. One ( Conclusion: Emerging data show that across the 4 dose levels tested, SC TAK-079 induced ORR in 43% of these heavily pretreated patients with no infusion reaction, no drug-related lymphopenia or thrombocytopenia, 4% rate of drug-related infections, and 11% drug-related anemia. TAK-079 SC has a low treatment burden with the low volume (2 mL) subcutaneous injections performed in ≤ 1-minute signifying the potential for home-based self-administration. The high potency of TAK-079 may result from selective binding to myeloma cells (ie less binding to RBC and platelets). Updated safety, efficacy, pharmacodynamics, and PK data for this heavily pre-treated RRMM population will be available for presentation at the meeting. Disclosures Krishnan: Celgene, Janssen, Sanofi, BMS: Consultancy; Sutro BioPharma, zPredicta: Consultancy; Celgene, Z Predicta: Other: Stock Ownership; Amgen, Takeda: Speakers Bureau; Takeda: Research Funding. Patel:Poseida Therapeutics, Cellectis, Abbvie: Research Funding; Oncopeptides, Nektar, Precision Biosciences, BMS: Consultancy; Takeda, Celgene, Janssen: Consultancy, Research Funding. Hari:AbbVie: Consultancy, Honoraria; Amgen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Cell Vault: Equity Ownership; Sanofi: Honoraria, Research Funding; Spectrum: Consultancy, Research Funding. Jagannath:Multiple Myeloma Research Foundation: Speakers Bureau; Celgene: Consultancy; Novartis: Consultancy; Merck: Consultancy; Medicom: Speakers Bureau; BMS: Consultancy. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding. Silbermann:Janssen, Sanofi: Other: Consultant/Advisor. Berg:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd: Employment, Patents & Royalties. Lin:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Fedyk:Millennium, a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd: Employment, Patents & Royalties. Palumbo:Millennium, a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd: Employment, Patents & Royalties. Stockerl-Goldstein:Abbott: Equity Ownership; AbbVie: Equity Ownership. OffLabel Disclosure: Investigation of TAK-079 for the treatment of relapsed and/ or refractory multiple myeloma

Background: The response to treatment for patients with relapsed/refractory multiple myeloma (MM) is highly variable. This may in part be related to the broad genomic heterogeneity that has been reported across individual patients. We hypothesize that in vitro functional drug screening and correlated genomic analyses of patient tumor cells is feasible and may improve clinical treatment response. To address this, we developed a custom high-throughput drug sensitivity (HTS) assay enabling simultaneous testing of 170 chemotherapy drugs and targeted inhibitors, as well as correlative gene expression and mutational analysis by next-generation sequencing. We report on the feasibility of this approach in a clinical trial enrolling patients with relapsed/refractory MM (NCT03389347). Patients and Methods: Twenty patients with relapsed/refractory MM or secondary plasma cell leukemia were enrolled in the study and 15 (9 female, 6 male) had a sufficient number of plasma cells for HTS. The average number of prior treatment regimens among the tested patients was 5.8 (range 3-11) and all had previously received a proteasome inhibitor and immunomodulatory drug and 8 had prior autologous stem cell transplants. Nine patients had stage III disease by the Revised International Staging System (R-ISS) and 4 had stage II disease. Eight patients exhibited high-risk cytogenetics, including 4 patients with del(17p), 5 patients with t(4;14), and 2 patients with t(14;16). The sources of plasma cells utilized for the HTS assay included bone marrow aspirate or core biopsies, soft tissue biopsies of plasmacytomas, and blood samples from patients with circulating plasma cells. Additional blood and bone marrow samples were obtained for RNA sequencing, whole-exome sequencing, and targeted sequencing of circulating tumor DNA. The CLIA approved HTS assay was performed at the Quellos HTS Core at the University of Washington using CD138+plasma cells isolated by magnetic bead separation. Tumor cells were tested against a panel of 170 drugs that includes conventional agents and targeted inhibitors, some FDA approved and others investigational. Cell viability was assessed at 72 hours by a luminescent cell viability assay (Cell Titer Glo, Promega) and drug response was determined using the concentration of experimental compound required to achieve 50% in vitro response inhibition (IC50) and area under the dose-response curve (AUC). Results: We report that the HTS assay can be completed in a median of 5 days from sampling (range 4-6 days), establishing feasibility. The mean percentage of bone marrow plasma cells among patients who could be tested was 56% compared to 5% for patients who had insufficient cells. We observed heterogeneity in patient genomic profiles and in vitro drug responses. The drugs with the highest in vitro response include those commonly used in MM such as bortezomib, ixazomib, carfilzomib, and panobinostat, as well as those under investigation including venetoclax and selinexor. Sensitivity was observed for drugs that have not been investigated for the treatment of MM including alvocidib and omacetaxine. Progression on prior therapy was not consistently predictive of in vitro drug responses and could be a consequence of some myeloma cells retaining sensitivity. Correlative genomic analyses were associated with in vitro drug responses for a subset of compounds. Among the 8 patients who received individualized therapy guided by the assay, 6 had an evaluable response and 5 (83%) achieved effective disease control (stable disease or better). Updated clinical treatment outcomes will be reported at the ASH conference. Conclusions: In this study, we successfully demonstrate the feasibility of a CLIA approved HTS assay capable of delivering actionable results in time to inform individualized treatment decisions for patients with MM. Correlative gene expression and mutational analysis are associated with in vitro drug response. Finally, we demonstrate that some of the patients who received treatment guided by the results of the HTS assay achieved a clinical response. These data suggest that using functional drug screening to predict sensitivity or resistance to both approved and experimental agents warrants further testing. Validation of the HTS assay in a larger population of MM patients holds the potential to improve treatment outcomes. Disclosures Cowan: Cellectar: Consultancy; Janssen: Consultancy, Research Funding; Abbvie: Research Funding; Celgene: Consultancy, Research Funding; Juno: Research Funding; Sanofi: Consultancy. Green:Celgene: Consultancy; Cellectar Biosciences: Research Funding; GSK: Consultancy; Juno Therapeutics: Consultancy, Patents & Royalties, Research Funding; Seattle Genetics: Research Funding. Libby:Alnylam: Consultancy; Abbvie: Consultancy; Pharmacyclics and Janssen: Consultancy; Akcea: Consultancy. Silbermann:Janssen, Sanofi: Other: Consultant/Advisor. Becker:The France Foundation: Honoraria; Accordant Health Services/Caremark: Consultancy; AbbVie, Amgen, Bristol-Myers Squibb, Glycomimetics, Invivoscribe, JW Pharmaceuticals, Novartis, Trovagene: Research Funding. OffLabel Disclosure: We will discuss in-vitro sensitivity testing of drugs that have not been approved for the treatment of multiple myeloma.

Background: The CD38-targeting antibody daratumumab, when combined with a proteasome inhibitor or with an immunomodulatory agent (IMiD) increases depth and duration of response in multiple myeloma (MM). Depth of remission post initial therapy as assessed by MRD predicts long term outcome in NDMM. We hypothesized that the combination of daratumumab, carfilzomib, lenalidomide and dexamethasone (Dara-KRd) would be safe and highly active in patients with NDMM. In addition, we assessed the feasibility of using MRD by next generation sequencing (clonoSEQ® method, sensitivity 10-6) to inform the use and duration of post-transplant Dara-KRd consolidation. Methods: Eligible patients (pts) had NDMM requiring treatment, creatinine clearance >40 ml/min, adequate liver and cardiac function, ECOG performance status 0-2 with no age limit. Treatment cycles consisted of daratumumab 16 mg/kg IV days 1,8,15,22 (with typical reduction in frequency with subsequent cycles), carfilzomib 56 mg/m2 IV days 1,8,15, lenalidomide 25 mg PO days 1-21 and dexamethasone 40 mg PO/IV days 1,8,15,22 repeated every 28 days. Patients received 4 cycles of Dara-KRd as induction, autologous transplantation, and received 0, 4 or 8 cycles of Dara-KRd consolidation, according to MRD status at each phase of therapy. MRD was evaluated by clonoSEQ® (NGS-MRD; Adaptive Biotechnologies, Seattle, WA) at end of induction, post-transplant, and during each 4-cycle block of Dara-KRd consolidation. Primary endpoint was achievement of MRD negative remission ( Results: Currently 69 pts have been enrolled, 38 have completed induction and 22 have completed post-transplant assessment. Median age was 61 (range 38-79) years, 13 (19%) had ISS 3, and 20 (29%) had high-risk chromosomal abnormalities [del17p, t(4;14) or t(14;16)]. Sixty-six (96%) pts had MRD trackable by clonoSEQ® and 100% of the expected MRD datapoints were successfully obtained. All patients responded by end of induction cycle 2, 92% of pts obtained VGPR or better after induction and 91% of patients who have reached transplant obtained CR/sCR as best response on therapy (Figure). MRD-negative remission ( Conclusion: This is the first report of monoclonal antibody-based quadruplet regimen with MRD-based response-adapted therapy in NDMM. Dara-KRd induction, autologous transplant and Dara-KRd consolidation guided by MRD is feasible, safe and leads to high proportion of patients achieving CR/sCR, IMWG MRD-negative CR, imaging plus MRD-negative CR and MRD Figure Disclosures Costa: Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy; Karyopharm: Consultancy; Fujimoto Pharmaceutical Corporation Japan: Other: Advisor. Cornell:Takeda: Consultancy; KaryoPharm: Consultancy. Silbermann:Janssen, Sanofi: Other: Consultant/Advisor. Dhakal:Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. Omel:Celgene, Takeda, Janssen: Other: Patient Advisory Committees. Hari:Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS: Consultancy, Research Funding; AbbVie: Consultancy, Honoraria; Cell Vault: Equity Ownership; Sanofi: Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Amgen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. OffLabel Disclosure: Carfilzomib for newly diagnosed multiple myeloma

Cardiac risk stratification (HCT-CI) for patients with multiple myeloma (MM) planning autologous hematopoietic stem cell transplant (ASCT) may not capture cardiovascular risk. In addition to more prevalent cardiovascular comorbidities, MM patients are also at risk for concurrent light chain cardiac

Bone marrow monocyte-/macrophage-derived activin A mediates the osteoclastogenic effect of IL-3 in multiple myeloma

Multiple myeloma is an incurable plasma-cell malignancy characterized by osteolytic bone disease and immunosuppression. Murine models of multiple myeloma and myeloma bone disease are critical tools for an improved understanding of the pathogenesis of the disease and the development of novel therapeutic strategies. This review will cover commonly used immunocompetent and xenograft models of myeloma, describing the advantages and disadvantages of each model system. In addition, this review provides detailed protocols for establishing systemic and local models of myeloma using both murine and human myeloma cell lines.

In this chapter, the contributions of cells in the immune system (monocyte-macrophages, myeloid derived suppressor cells, mesenchymal stromal cells, T cell subsets, NK cells, dendritic cells, and B cells) to bone metastasis, and multiple myeloma bone disease will be reviewed. In addition, the effects of tumor-derived products, such as lactic acid, that is also produced by bone cells, on the suppression of antitumor responses that are required for tumor growth in bone, will be discussed. All of these components of the immune system are major contributors to the growth and bone altering effects of tumor cells in bone.

Multiple myeloma (MM) is the most frequent cancer to involve the skeleton and remains incurable for most patients, thus novel therapies are needed. MM bone disease is characterized by osteolytic lesions that contribute significantly to patient morbidity and mortality. We showed that TBK1 signaling is a novel pathway that increases osteoclast (OCL) formation in Paget's disease, an inflammatory bone disease. Therefore, we hypothesized that TBK1 plays a similar role in MM induction of OCL. We found that MM conditioned media (MM-CM) dose-dependently increased bone marrow monocyte (BMM) expression of activated TBK1 protein and enhanced RANKL-driven OCL formation. TBK1 knockdown by shRNA transduction into BMM significantly attenuated the ability of MM-CM to increase OCL differentiation without altering OCL differentiation in control media. We found that the TBK1/IKKε inhibitor Amlexanox (Amlx) blocked normal and MM-enhanced OCL formation. Importantly, TBK1 mRNA expression in CD138+ plasma cells (PC) isolated from MM or PC leukemia patients is significantly higher as compared to PC from Monoclonal Gammopathy of Undetermined Significance (MGUS) patients. Therefore, we tested whether targeting the TBK1/ IKKε signaling pathways would also affect MM cells. We found that Amlx strongly decreased the viability of several MM cell lines and primary MM cells via induction of apoptosis. Amlx treatment of MM cell lines also induced a G1/S blockade, decreased activated ERK1/2, and increased translation of the dominant-negative C/EBPb-LIP isoform in several MM cell lines. The positive-acting C/EBPb-LAP isoform was previously shown to be a critical transcription factor for MM viability. Importantly, Amlx also enhanced the effectiveness of the proteasome inhibitors bortezomib and carfilzomib to kill MM cells in culture. Further, Amlx sensitized MM1.S cells to the induction of apoptosis by the autophagic inhibitor Bafilomycin A. Amlx dose-dependently inhibited tumor growth in a syngeneic MM mouse model in which 5TGM1 MM cells expressing secreted GLuc were injected subcutaneously into immunocompetent C57Bl/KaLwRij. Tumor growth was assessed by measuring tumor volumes and by the levels of secreted GLuc in the blood. Further, OCL formation ex vivo from bone marrow monocytes obtained from AMLX-treated mice versus controls was decreased. Amlx did not affect the viability of primary BMM, bone marrow stromal cells (BMSC), or splenocytes. Further, Amlx treatment of primary BMSC from MM patients or normal donors decreased expression of TNFα, IL-6 and RANKL, thereby decreasing BMSC support of MM survival and OCL differentiation. Amlx pretreatment of BMSC and murine pre-osteoblast MC4 cells also decreased VCAM1 expression and reduced MM cell adhesion, another mechanism for Amlx reduction of bone microenvironmental MM support. These data suggest that targeting TBK1/IKKε signaling may decrease MM bone disease by slowing MM growth, directly and indirectly, and preventing MM-induced osteolysis. Disclosures Giuliani: Janssen Pharmaceutica: Other: Avisory Board, Research Funding; Celgene Italy: Other: Avisory Board, Research Funding; Takeda Pharmaceutical Co: Research Funding. Roodman:Amgen Denosumab: Membership on an entity's Board of Directors or advisory committees.

The bone is a frequent site for tumor metastasis, and cancer in the bone results in marked disturbances of bone remodeling that can be lytic, blastic or a combination of the two. Patients with advanced malignancies that have metastasized to the bone frequently suffer from debilitating skeletal-related events, including pathologic fractures, spinal cord compression syndromes, disorders of calcium and phosphate homeostasis and severe cancer-related pain. This review will discuss recent studies on the mechanisms responsible for osteolytic and osteoblastic metastasis and how their identification has resulted in the development of new agents for patients with metastatic bone disease.

Mucosal surfaces serve as a gateway to disease. Here, we demonstrate that RNA interference can be used to manipulate mucosal gene expression in vivo. Using a murine model, we show that direct application of liposome-complexed siRNA mediates gene-specific silencing in cervicovaginal and rectal mucosa. A single vaginal or rectal administration of siRNA targeting hematopoietic or somatic cell gene products reduced corresponding mRNA levels by up to 90%. Using a murine model of inflammatory bowel disease, we found that the rectal application of siRNA targeting TNF-alpha led to relative mucosal resistance to experimental colitis. Liposomal siRNA formulations proved nontoxic, did not elicit a nonspecific interferon response, and provide a means for genetic engineering of mucosal surfaces in vivo.

Multiple myeloma (MM) is the most frequent cancer to involve the skeleton with patients developing osteolytic bone lesions due to hyperactivation of osteoclasts (OCL) resulting in severe bone pain, pathological fractures and enhanced mortality. These bone lesions rarely heal even after therapeutic remission due to MM-induced suppression of bone marrow stromal cells (BMSC) differentiation into functional osteoblasts (OB), enhancing their support of MM growth and survival. Although new therapies for MM have greatly improved progression-free survival and overall survival, MM remains incurable for most patients. EZH2is the methyltransferase subunit of the Polycomb Repressive Complex 2 (PRC2) catalyzing the tri-methylation of histone-3 lysine-27 (H3K27me3), which induces gene repression. We previously reported that MM cells induce increased recruitment of EZH2 to the Runx2 gene in the murine pre-OB cell line MC4 resulting in H3K27me3-mediated repression of Runx2, thereby causing repression of OB differentiation. In the present study, we show that the repressive H3K27me3 levels are elevated with reduced H3K9 acetylation on the Runx2 promoter in MM patient derived BMSC. Using the selective small molecule inhibitor GSK126 to block EZH2 activity, we investigated if the MM-induced epigenetic repression of Runx2 is reversible. We found that GSK126 enhances the active architecture at the Runx2 promoter in both BMSC from MM patients and MM-treated MC4 cells, and rescues the osteogenic potential and mineralization capability. 5TGM1 MM cells exhibited reduced adhesion to MC4 pre-OB pre-treated with GSK126 as compared to vehicle in an in vitro adhesion assay, suggesting that EZH2 inhibition will decrease pre-OB support for MM cells. In addition to the direct osteo-anabolic effects of EZH2 inhibition on OB differentiation, we investigated if GSK126 treatment affected the pro-inflammatory, myeloma-amplified OCL differentiation that results in enhanced osteolysis in MM. We reported that expansion of bone marrow monocytes (BMM), which are OCL precursors, in the presence of MM1.S-conditioned media, significantly enhanced formation of TRAP-positive multinucleated OCL. Here we show that MM-conditioned media significantly increased EZH2 and OCL marker genes NFATc1, RANK, OSCAR, Cathepsin K, and DC-STAMP mRNA and enhanced RANKL-induced formation of OCL, which was blocked by GSK126. We found that EZH2 and the corresponding H3K27me3 levels increase during the initial 24h of RANKL-induced osteoclastogenesis and that GSK126 inhibition during the first 24h of RANKL treatment was necessary and sufficient to decrease formation of mature OCL. Thus, GSK126 is likely to both protect the bone from new lytic lesions and help heal the existing osteolytic lesions in MM. We found that GSK126 treatment (48h) inhibited proliferation of human (MM1.S, RPMI, U266, H929, and JJN3) and murine (5TGM1) MM cell lines, and primary 138+MM patient cells. We analyzed the interaction of GSK126 and bortezomib using IC50 constant ratio drug combinations based on the Chou & Talalay method using the CompuSyn program. We found that GSK126 synergizes with bortezomib to inhibit cell viability of these MM cell lines and activated apoptosis via induction of activated caspase-3. We used 5TGM1-GLuc-GFP cells, which secrete Guassia luciferase (GLuc), to measure MM cell viability in a longitudinal drug treatment study. GLuc levels in media correlated with cell proliferation, which was inhibited by single and combination doses of GSK126 and bortezomib, further demonstrating the synergism of these drugs. GSK126 decreased EZH2 mRNA and protein levels in MM cells, which is a cell-type specific effect, since we did not observe EZH2 protein alteration in GSK126 treated OCL progenitors. Our in vitro study suggests that selective inhibition of the epigenetic modifier EZH2 using GSK126 would positively regulate the bone microenvironment by improving the osteogenic potential of MM-exposed BMSC and suppressing OCL formation, and would directly decrease MM cell survival, particularly in combination with bortezomib. These data suggest that targeting EZH2 activity alone or in combination with bortezomib may prove a valuable therapeutic strategy to improve bone health and limit disease progression in MM patients. Disclosures Roodman: Amgen: Consultancy.

Multiple myeloma (MM) is a plasma cell malignancy characterized by monoclonal paraprotein production. It is the second most common hematologic malignancy and has the highest incidence of bone involvement amongst malignant diseases. Up to 90% of patients with MM have evidence of osteolysis in the form of generalized osteopenia or discrete lytic lesions. Skeletal lesions in MM are distinct from bone involvement in other malignancies and are characterized by generalized increased osteoclast activity and suppressed osteoblast function with decreased new bone formation. This chapter will review the pathophysiology of myeloma bone disease and discuss current treatment strategies and novel targets for management of myeloma bone disease.

Multiple myeloma is the second most common hematological malignancy and the most frequent cancer to involve the skeleton. Multiple myeloma bone disease (MMBD) is characterized by abnormal bone remodeling with dysfunction of both bone resorption and bone formation, and thus can be used as a paradigm for other inflammatory bone diseases, and the regulation of osteoclasts and osteoblasts in malignancy. Studies of MMBD have identified novel regulators that increase osteoclastogenesis and osteoclast function, repress osteoblast differentiation, increase angiogenesis, or permanently alter stromal cells. This review will discuss the current understanding of mechanisms of osteoclast and osteoblast regulation in MMBD, and therapeutic approaches currently in use and under development that target mediators of bone destruction and blockade of bone formation for myeloma patients, including new anabolic therapies.

Background: High-dose melphalan and autologous hematopoietic stem cell transplantat (auto-HCT) is a standard consolidation therapy for eligible multiple myeloma (MM) patients due to superior survival outcome as compared to chemotherapy alone. However, patients remain at continuous risk of disease relapse following auto-HCT. Lenalidomide is active in newly diagnosed and relapsed MM and has synergistic activity with melphalan, but has not previously been incorporated into preparative regimen for auto-HCT. While high dose lenalidomide induces myelosuppression, the anti-tumor activity of lenalidomide is dose-dependent. Methods: We conducted a single center, phase I/II study of lenalidomide and melphalan in patients with MM undergoing auto-HCT. The phase I portion included MM patients at all disease stages, including patients undergoing auto-SCT as salvage therapy. The phase II portion enrolled patients undergoing a first auto-SCT after achieving at least stable disease following their induction regimen. Phase I objectives included determination of side effect profile and recommended phase II dose (RP2D). Phase II objectives were disease response at day +100 and toxicity. Treatment: All patients received a standard melphalan dose of 200 mg/m2 (100 mg/m2 IV days -1 and -2). Phase I lenalidomide dose was escalated from 50 mg, 75mg, 100 mg, and 150 mg and administered orally daily from days -7 to +2. Phase I data were previously reported (Blood (ASH Annual Meeting Abstracts), Nov 2012; 120: 3146). Thirteen patients were treated and no MTD was reached. The RP2D lenalidomide dose (150 mg orally daily days -7 to +2) was further explored in the phase II portion of this study. Post-transplant lenalidomide maintenance therapy was started between days +100 and +120 in all responders. We now report the planned interim analysis of the efficacy and safety profile of the phase II study. Results: From 5/1/12 to 7/9/15, forty seven subjects were enrolled to the phase II portion of the study. Study accrual is complete. We report below on the 37 patients with at least 100 days follow-up (median duration of follow-up of 12 months). 36 patients were assessable for response. Responses are as followed: stringent CR 8 (22%), CR 3 (8%), VGPR 20 (54%), PR 3 (8%), progressive disease 2 (5%). Among responders, 34 were able to start maintenance lenalidomide on days +100 to +110 (two withdrew from the study to pursue tandem stem cell transplant). To date, 21 patients remain on the treatment. Of 13 who discontinued the therapy; 4 was due to progression, 4 due to physician/patient preference, 2 due to toxicities and 3 from other reasons. Median progression free survival has not been reached. Toxicities were considered treatment related if they occur after the initiation of study drugs. DLTs are defined as any AEs occurring from days -7 to -2 that cause delay or prevent subjects from proceeding to auto-SCTs, grade 3 or more non-hematologic toxicities that do not resolve to a grade 2 or less by day 30 after auto-SCT, or engraftment failure. No DLTs were observed. The median time for ANC and platelet engraftment was 12 and 15 days and no delayed engraftment was observed. Toxicities and posttransplant hematopoietic recovery rates were similar to historical data observed with single agent high dose melphalan. Lenalidomide related toxicities occurred more commonly during the maintenance phase. Common toxicities occurring in more than 10% of patients were diarrhea (24%), peripheral neuropathy (21%) and fatigue (10%). Grade 3-4 toxicities occurred in 16% percent of patients: fatigue (5%), neutropenia (5%) neuropathy (3%), and thrombocytopenia (3%). Conclusion The use of high dose lenalidomide in combination with high-dose melphalan as a preparative regiment for auto-SCT is well tolerated. High VGPR or better disease response rates, compared to historical control, suggest that the preparative combination regimen may improve the depth of response. Stem cell rescue likely overcome lenalidomide induced myelosuppression. The study is now closed to accrual. Updated data on primary endpoints from all subjects will be reported at the meeting. Disclosures Suvannasankha: Celgene: Research Funding, Speakers Bureau; Onyx: Research Funding, Speakers Bureau. Farag:Bristol Myers: Speakers Bureau; Millennium: Speakers Bureau; Teva: Research Funding; Celgene: Speakers Bureau. Silbermann:Amgen: Consultancy; Celgene: Research Funding. Abonour:Celgene: Research Funding, Speakers Bureau.

Bone metastases occur frequently in patients with advanced cancer. It is estimated that up to 70% of patients with advanced prostate or breast cancer and 15 to 30% of patients with lung, colon, stomach, bladder, uterus, rectum, thyroid, or kidney cancer have bone metastases [1]. While the exact incidence of bone metastasis is not known, it is estimated that 350,000 cancer patients die with bone metastases in the United States annually [2]. The consequences of bone metastases are severe and include pain, hypercalcemia, pathologic fractures, and nerve-compression syndromes. This special issue of Cancer Microenvironment focuses on recent developments in our understanding of the microenvironment of bone metastases and includes articles on the homing of tumor cells to the bone, the roles of hematopoietic stem cell and stromal cell populations in the development of metastatic lesions and a review of the interactions between prostate cancer cells and the tumor microenvironment in the development of bone metastases from prostate cancer. In addition, this issue includes submissions discussing the role of TGF-β in the bone microenvironment of breast cancer and the effect of rigidity on the regulation of genes that stimulate tumor-induced bone disease. Finally, three articles are dedicated to the unique pathophysiology of the bone microenvironment in myeloma bone disease. Myeloma bone disease is distinct from bone disease caused by other tumors that are metastatic to bone as myeloma bone leisons are characterized by severely decreased or absent osteoblast activity in addition to increased osteoclastic bone resorption [3]. This issue includes articles discussing recent progress in the understanding of the mechanisms regulating myeloma bone disease, the angiogenic properties of the myeloma marrow microenvironment, and a summary of our current understanding of osteoblast inhibition in myeloma and the potential therapeutic utility of bone anabolic agents in managing this devastating disease.

Agents used for systemic chemotherapy can alter normal bone homeostasis through mechanisms that affect both osteoblast and osteoclast function. The identification of those agents that influence maintenance of the bone-remodeling compartment is an important component of the drug development and testing process. This brief review focuses on preclinical and clinical data illustrating the effect of several classes of chemotherapeutic agents on skeletal development and bone remodeling.New preclinical data demonstrate that several classes of chemotherapeutic agents, including histone deacetylase inhibitors and proteasome inhibitors, alter osteoblast and osteoclast function. Preclinical data on retinoic acid analogues demonstrate that these agents inhibit osteoclastogenesis. In addition, a dose-dependent effect of methotrexate treatment on growth plate thickness and primary spongiosa height in rats has been demonstrated. Two recently published analyses of clinical data from trials of bortezomib in myeloma patients found increased biochemical markers of bone formation and evidence of increased bone deposition after bortezomib treatment.Several classes of chemotherapeutic agents alter bone metabolism and negatively impact bone homeostasis. Bone mineral density (BMD) monitoring guidelines for patients receiving systemic chemotherapy are not established. Limited guidelines exist for BMD monitoring in patients receiving long-term hormonal modulation; however, the negative effect of other chemotherapeutic agents on the skeleton is underappreciated.

Bone disease in multiple myeloma is characterized by lytic lesions that are frequently associated with fracture, hypercalcemia, and severe pain. Bone pain is the most frequent presenting symptom for patients with multiple myeloma. It is estimated that approximately 60% of patients have bone pain at the time of myeloma diagnosis and 90% of patients develop bone lesions during their disease course. In addition to lytic lesions, patients frequently develop diffuse osteopenia, pathologic fractures, and compression fractures of the spine. Bone disease significantly impacts patient morbidity, performance status, and survival. While there is an association between the number of lytic bone lesions in an individual and their disease burden, an individual’s degree of bone disease does not appear to have significant utility in predicting outcomes.

Multiple myeloma (MM) bone disease is characterized by bone destruction with suppressed bone formation resulting in enhanced tumor growth. We previously showed that IL3 is a multifunctional cytokine that is elevated in the marrow plasma of MM patients as compared with healthy subjects and that IL3 increases myeloma cell and osteoclast (OCL) precursor proliferation and suppresses osteoblastogenesis via an indirect mechanism mediated by bone marrow monocyte / macrophages (BMM). In addition, IL3 has widespread proliferative and differentiation effects on multiple hematopoietic cell types. Thus attempts at targeting IL3 to date have been unsuccessful due to IL3's impact on normal hematopoiesis. Therefore, identification of IL3's downstream effects in MM bone disease is critical for effective targeting of IL3 in MM. We demonstrated that IL3 induces human OCL formation and that an IL3 neutralizing antibody inhibits OCL formation stimulated by bone marrow (BM) plasma containing high levels of IL3 from MM patients. We recently reported that treatment of MM patient CD14+ BMM with IL3 induces high levels of Actvin A (ActA), a TGF-β superfamily member that, like IL3, modulates MM bone disease by enhancing osteoclastogenesis and inhibiting osteoblasts. As IL3 induces ActA secretion from CD14+ BMM, and has a very similar effect to IL3 on OCL formation, we treated OCL precursors with IL3 in the presence of a neutralizing antibody to ActA (anti-ActA) and demonstrated that anti-ActA dose-dependently inhibited the osteoclastogenic effect of IL-3 on OCL formation. We also showed that ActA stimulates osteoclastogenesis via a RANKL-independent mechanism, and that, in support of early OCL precursors as the source of ActA induced by IL3, IL3 receptor expression is highest on early OCL precursors and decreases during OCL differentiation. We now report in vivoconfirmation of IL3's osteoclastogenic effects. Female C57BL mice were injected intraperitoneally with saline or anti-ActA for 7 days. Beginning on day 3, mice were injected subcutaneously over the calvaria with IL3 or saline daily for 5 days. Mice were sacrificed after 7 days and calvaria were sectioned and stained for TRAP. A blinded observer performed quantitative histologic analyses, and TRAP+ OCL were counted on the endosteal bone surfaces. TRAP+ OCL numbers on the endosteal bone surfaces (N.Oc), corrected for bone surface area (BS), were dramatically increased by IL3 treatment compared to saline treated controls (mean N.Oc/BS supracalvarial IL3 treatment 18.51, SD 2.14 vs saline control 13.42, SD 1.18, p Disclosures: Roodman: Amgen: Consultancy; Eli Lilly and Co.: Research Funding. Giuliani:Celgene Italy: Research Funding.

Multiple myeloma (MM) cells activate multiple signaling pathways in bone marrow stromal cells (BMSC), which results in enhanced tumor growth, increased osteoclast (OCL) formation and activity, and profound inhibition of bone formation by osteoblasts (OBL). We recently showed that sequestosome-1 (p62) acts as a signaling hub for these pathways, including MM-cell induced NFκβ, p38MAPK, and PI3K activation in MM patient BMSC, and that the p62 ZZ domain is required for BMSC enhancement of MM cell growth, IL-6 production, VCAM-1 expression and OCL formation. To target the ZZ domain we developed a small molecule inhibitor (CMPD3) that specifically blocked p62-ZZ domain mediated protein interactions required for BMSC support of tumor / OCL formation, but had no effect on CFU-blasts. We now report characterization of CMPD3 in an in vivomodel of MM. Murine MM cells (5TGM1-tk-gfp) were implanted intra-tibially in female SCID mice and male C57BL/KaLwRij mice and allowed to engraft for 2 weeks. Pilot PK studies using a multiple dose MTD of 60mg/kg IV in female SCID mice bearing MM cells demonstrated a terminal t1/2 of CMPD3 in plasma of greater than 5 hours (h), and extratibial tumor CMPD3 concentrations ranging between 5 and 10-fold higher than plasma. A pilot efficacy study in male C57BL/KaLwRij mice based on the multiple dose MTD demonstrated that mice treated with CMPD3 lost weight compared with vehicle treated mice. CMPD3 treatment did not alter activity scores of the mice or plasma IgG2b levels, a marker of tumor burden. Both compartmental and non-compartmental pharmacokinetic analysis of plasma concentrations of CMPD3 in the male C57BL/KaLwRij mice on the multiple dosing regime after doses of 27 mg/kg/day or 40 mg/kg/day ip resulted in a plasma terminal t1/2 of 10 -12 h and a clearance of 1188 ml/h/kg. An expanded efficacy study using CMPD3 doses of 27mg/kg/day or 40mg/kg/day, or vehicle ip for 5 days/week for 2 weeks demonstrated no change in body weights, tumor scores, or plasma IgG2b levels in any animals. Radiographic analysis of tibiae confirmed the presence of lytic bone lesions in all animals, and of 27 evaluable animals at the end of treatment, 6 CMPD3 treated and 2 vehicle treated mice developed grade 4 tumors (defined as tumor expanding outside the tibia and impairing the use of the limb). 4 of the 6 CMPD3 treated mice with grade 4 tumors and 1 of the 2 vehicle treated animals had radiographic evidence of new bone formation on the anterior tibial surface. µCT analysis of the tibiae from all CMPD3 vs. vehicle treated mice showed that the ratio of new bone volume to total bone volume (NBV/TBV) was increased in CMPD3 treated mice regardless of tumor score (1 - 4) (p=0.015). Stratification of NBV/TBV based on tumor score showed that CMPD3 treated animals with a tumor score of 4 had significantly more new bone formation than animals with tumor scores of 1 - 3 (p Thus, CMPD3 induces new bone formation in bones bearing MM and suggest that p62 ZZ inhibition modulates tumor induced OBL suppression. Non-compartmental analysis of the maximal plasma concentration of CMPD3 at the 40mg/kg dose was 5.7µM, while the in vitro IC50 of CMPD3 for 5TGM1 cells was 4.35µM. This difference may explain why IgG2b levels did not change with CMPD3 treatment. In contrast, the IC50 in OCL formation assays was 0.1µM, suggesting that CMPD3’s inhibition of OCL formation in vivo may also contribute to increased bone. These findings demonstrate that CMPD3 can modulate tumor cell – bone cell interactions in MM in vivo, and support development of CMPD3 as a potential anabolic bone agent for MM. Disclosures: Roodman: Amgen: Consultancy; Eli Lilly and Co.: Research Funding.

Abstract 3146 Background: High dose chemotherapy and stem cell transplantation (HDSCT) has been a standard of care for younger patients with adequate organ function since the early 1980s, due to its superiority over standard chemotherapy in prolonging disease-free and overall survival. Immunomodulatory agents, including thalidomide and lenalidomide, have significant single-agent activity and an additive effect when combined with melphalan. Preclinical data suggest an increased DNA damage and an anti-angiogenic effect with the combination. Additive clinical benefits were also observed when the 2 agents were used in combination in non-transplant settings. The antimyeloma effects of both agents are dose-dependent with myelosuppression being the dose limiting toxicity (DLT). This toxicity can be attenuated with stem cell rescue. Purpose: We conducted a phase I/II trial designed to evaluate the safety and efficacy of combining lenalidomide with high-dose melphalan as conditioning for autologous transplant for myeloma. The phase I portion of the study is complete and the results are reported in this abstract. Experimental Design: The enrolled patients included any patients with myeloma, regardless of the status of the disease, undergoing high dose melphalan for autologous stem cell transplantation. The melphalan dose was fixed (200 mg/m2) while the doses of lenalidomode were escalated from 50, 75, 100, and 150 mg/m2 administered orally days -7 to +2 of the transplantation. Dose escalation was based upon a 3+3 phase I design. DLTs were defined as grade ≥4, both hematologic and non-hematologic, occurring between days -7 to -2 which prevents subjects from undergoing stem cell transplantation, or grade 3 or 4 non-hematologic toxicity occurring after day -2 that does not resolve to a grade 2 or less by day +30 after transplantation, or delayed engraftment. The response was assessed at day +100 post transplantation using the International Myeloma Working Group criteria. Results: 13 patients participated in the phase I portion of the study from September 2010 to May 2012. Patients ages ranged from 42– 72 years (median 63 years). Seven patients were undergoing their first autologous transplant with 2 patients having had 2 lines of previous therapy and 5 having one line of therapy. Six patients were undergoing their second transplantationas salvage for control of progressive disease and all had more than 3 lines of prior therapy. At baseline, 5 patients had progressive disease, 1 had SD, 3 had PR, 3 had VGPR and 1 had CR as responses to their most recent lines of therapy. The median time for ANC and platelet engraftment was 10 days and no delayed engraftment was observed. Toxicities and posttransplant hematopoietic recovery rates were similar to historical data observed with single agent high dose melphalan. The most common grade ≥ 3 adverse events were myelosuppression, neutropenic fever and electrolyte abnormalities, all of which are commonly observed with single agent high dose melphalan. Adverse events related to the study drugs were electrolyte abnormalities (hypokalemia, hyperkalemia and hypocalcemia), gastrointestinal side effects and rash, all of which were grade 1 to 2 and manageable without a delay or discontinuation of the study drugs. One patient died from disease progression prior to scheduled disease evaluation. One patient has not yet reached day +100 post transplant. Therefore, responses were evaluable for 11 patients. Three patients achieved stringent CR (27%), 3 CR (27%), 2 VGPR (18%), 3 PR (27%) and one had progressive disease (9%). The overall response rate was 91%, with 72% achieving VGPR or better. All patients had adequate count recovery and were able to initiate lenalidomide maintenance treatment by day +100 to +110 post transplantation. Conclusions: The use of high dose lenalidomide in conjunction with high-dose melphalan is well tolerated, with preliminary data suggesting that the combination is highly efficacious. DLT was not observed; therefore the recommended phase II dose is 150 mg of lenalidomide orally on days -7 to +2 in combination with melphalan 200 mg/m2. The phase II portion of this trial is ongoing in patients undergoing first HDSCT. Complete response at 3 months post transplantation is the primary end point. Disclosures: Off Label Use: Lenalidomide in myeloma transplant. Abonour:Celgene: Honoraria, Speakers Bureau; Millenium: Honoraria, Speakers Bureau.

Abstract 3933 Multiple myeloma (MM) is characterized by bone destruction with suppressed new bone formation that is mediated by multiple factors including MIP-1α (CCL3), RANKL, IL-3, DKK1 and recently, Activin A (ActA). IL-3 is a bifunctional cytokine that indirectly increases osteoclastogenesis and suppresses osteoblastogenesis via CD14+ bone marrow monocytes (BMM). Additionally, IL-3 levels are elevated in the BM plasma of MM patients compared with normals, however the mediators of IL-3's effects on myeloma bone disease are unknown. To investigate this we performed gene expression profiling using Affymetrix GeneChip® analysis of IL-3 treated BMM from MM patients and found ActA gene expression was increased 180-fold and confirmed this finding at the protein level by ELISA. ActA is a negative regulator of bone mass that promotes osteoclastogenesis and is overproduced in MM patients. Interestingly, treatment of MM cells or bone marrow stromal cells (BMSC) with IL-3 did not induce secretion of ActA. We found that ActA was produced by MM and MGUS patient CD14+ cells treated with IL-3 to a significantly higher degree compared to healthy subjects. (Median ActA levels for MM and MGUS ActA levels were increased 66.57 and 51.6 fold respectively over untreated cells, while IL-3 treatment of normal cells increased ActA 8.5 fold.) ActA levels were also increased in freshly isolated marrow plasma of a cohort of patients with active MM as compared to patients with smoldering MM (SMM), MGUS, or healthy subjects (median ActA levels: active MM 453 pg/ml, SMM 328 pg/ml, MGUS 332 pg/ml, normal 286 pg/ml). ActA levels in MM patients with and without bone disease were not significantly different. (Median value with bone disease 463pg/ml vs. 407 pg/ml without bone disease.) ActA has also been reported to have a role in the differentiation and polarization of CD14+ tumor associated macrophages (TAMs), which are osteoclast precursors and can block MM cell apoptosis. Therefore, we examined the potential role of ActA in IL-3 mediated osteoclast (OCL) formation. Culture of normal BMM with ActA or IL-3 significantly enhanced osteoclastogenesis compared with control (mean number of OCL / 1×105 normal marrow non-adherent cells plated in IL-3 (100pg/ml) treated cultures 73; ActA (1ng/ml) treated cultures 123; cultures with vehicle alone, 8), and ActA enhanced RANKL-induced osteoclastogenesis. Osteoprotegerin treatment of normal donor BMM stimulated with ActA failed to block the osteoclastogenic effects of ActA, demonstrating that ActA's osteoclastogenic effects were RANKL independent. Importantly, the osteoclastogenic effect of IL-3 was dose-dependently inhibited by anti-ActA, and IL-3 induced ActA expression by BMM decreased during OCL differentiation. In support of early OCL precursors as the source of IL-3 induced ActA, we did not identify IL-3 receptors on mature OCL by flow cytometry. These results demonstrate that IL-3 induction of osteoclastogenesis is mediated by ActA produced by CD14+ BMM and is RANKL independent. Thus, we hypothesize that therapies targeting the ActA receptor, such as the recently developed ActA receptor antagonist, should block both IL-3 and ActA, and thereby significantly impact MM bone disease via their effects on TAMs. Disclosures: Bolzoni: Celgene Italy: Research Funding. Roodman:Millennium: Consultancy; Amgen: Consultancy. Giuliani:Celgene: Research Funding; Novartis: Research Funding.

Multiple myeloma bone disease is marked by severe dysfunction of both bone formation and resorption and serves as a model for understanding the regulation of osteoblasts (OBL) and osteoclasts (OCL) in cancer. Myeloma bone lesions are purely osteolytic and are associated with severe and debilitating bone pain, pathologic fractures, hypercalcemia, and spinal cord compression, as well as increased mortality. Interactions within the bone marrow microenvironment in myeloma are responsible for the abnormal bone remodeling in myeloma bone disease. Myeloma cells drive bone destruction that increases tumor growth, directly stimulates the OCL formation, and induces cells in the marrow microenvironment to produce factors that drive OCL formation and suppress OBL formation. Factors produced by marrow stromal cells and OCL promote tumor growth through direct action on myeloma cells and by increasing angiogenesis. Current therapies targeting MMBD focus on preventing osteoclastic bone destruction; however regulators of OBL inhibition in MMBD have also been identified, and targeted agents with a potential anabolic effect in MMBD are under investigation. This review will discuss the mechanisms responsible for MMBD and therapeutic approaches currently in use and in development for the management of MMBD.

Background: Magrolimab is a humanized monoclonal antibody that blocks the immune checkpoint CD47, a "do not eat me" signal, overexpressed on tumor cells. The binding of magrolimab to CD47 leads to phagocytosis of cancer cells from human solid tumors and hematologic malignancies. The overexpression of CD47 contributes to the pathogenesis of multiple myeloma (MM) and blocking CD47 induces immediate activation of macrophages and elimination of myeloma cells (Sun et al). Hence, a blockade of CD47 with magrolimab may have therapeutic benefit in patients with MM. Combination therapies are more effective than single-agent therapy for both newly diagnosed and relapsed/refractory MM (RRMM). In vitro studies show synergy between magrolimab and daratumumab on MM cell line phagocytosis, and complimentary mechanisms suggest potential enhanced efficacy in other combinations. The current study (NCT04892446) is investigating the efficacy of magrolimab in combination with commonly used myeloma therapies in patients with RRMM. Design and Methods: This phase 2, multi-arm study includes patients aged ≥18 years currently requiring treatment for RRMM; all participants must have received at least 3 previous lines of therapy for MM, including an immunomodulatory drug and a proteasome inhibitor. This study includes 2 phases: a safety run-in cohort and a dose-expansion cohort (Figure 1). The primary objectives of the safety run-in cohort are to evaluate the safety and tolerability of magrolimab in combination with other anticancer therapies using the occurrence of dose-limiting toxicities (DLTs) as the primary endpoint, and to determine the recommended phase 2 dose (RP2D) of magrolimab in the following combinations: magrolimab+daratumumab; magrolimab+pomalidomide+dexamethasone; and magrolimab+bortezomib (maximum of 8 prior cycles in those who previously received bortezomib)+dexamethasone. Dose expansion cohorts will evaluate the efficacy of magrolimab combinations with objective response rate (ORR) as the primary endpoint. Secondary endpoints include duration of response, progression-free survival, and overall survival. Minimal residual disease negativity, biomarker changes from baseline, immune cell signaling alterations, and the mutational profile of plasma cell clones will also be explored. Magrolimab is administered intravenously (IV) with an initial priming dose, followed by a maintenance dose on days 8, 15, 22, and 29 during cycle 1 (35 days) and days 1, 8, 15, and 22 from cycle 2 (28 days) onwards. Daratumumab, pomalidomide, dexamethasone, and bortezomib will be administered according to manufacturer's prescribing information. Dose de-escalation may occur based on DLTs per protocol. Patients will continue treatment until unacceptable toxicity, progressive disease, or patient/investigator choice to discontinue. Planned enrollment is approximately 153 patients. Status: Recruitment is ongoing. Reference: Sun J, Muz B, Alhallak K, Markovic M, Gurley S, Wang Z, Guenthner N, Wasden K, Fiala M, King J, Kohnen D, Salama NN, Vij R, Azab AK. Targeting CD47 as a novel immunotherapy for multiple myeloma. Cancers (Basel). 2020;12(2):305. Figure 1 Figure 1. Disclosures Paul: Amgen Inc.: Speakers Bureau; Bristol Myers Squibb: Divested equity in a private or publicly-traded company in the past 24 months; Genentech: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals Inc: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Regeneron: Membership on an entity's Board of Directors or advisory committees. Liedtke: Celgene: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Takeda: 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; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees. Monge: Karyopharm Therapeutics: Research Funding; Bristol Myers Squibb: Consultancy. Rifkin: Takeda: Membership on an entity's Board of Directors or advisory committees; Fresenius-Kabi: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; McKesson: Current Employment, Current equity holder in publicly-traded company; Coherus: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb (Celgene): Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Gandhi: Karyopharm Therapeutics: Honoraria; TG Therapeutics: Honoraria; GlaxoSmithKline: Honoraria. Kovacsovics: Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Stemline: Honoraria; Jazz Pharmaceutials: Honoraria; Novartis: Research Funding; AbbVie: Research Funding. Levy: Bristol Myers Squibb: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; GSK: Consultancy, Other: Promotional speaker; Novartis: Consultancy, Other: Promotional speaker; Amgen Inc.: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Gilead Sciences, Inc.: Consultancy, Honoraria, Speakers Bureau; Epizyme: Consultancy, Other: Promotional speaker; Morphosys: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Janssen Pharmaceuticals: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Beigene: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Dova: Consultancy, Other: Promotional speaker. Siegel: Karyopharm: Honoraria; Celularity: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria, Speakers Bureau; Takeda: Honoraria; Bristol Myers Squibb: Honoraria, Speakers Bureau; Amgen Inc.: Honoraria; Janssen: Honoraria, Speakers Bureau. Silbermann: Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees, Research Funding. Byrne: Gilead Sciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Ncube: Gilead Sciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Murphy: Gilead Sciences, Inc.: Current Employment, Current holder of stock options in a privately-held company. Gu: Gilead Sciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Rajakumaraswamy: Gilead Sciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Chao: Gilead Sciences, Inc.: Current Employment; TigaTx: Membership on an entity's Board of Directors or advisory committees; Stanford University: Patents & Royalties; Hepatx Inc: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Iconovir Bio: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Leukemia and Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; Stanford University Medical School: Membership on an entity's Board of Directors or advisory committees; Foresite capital: Consultancy; Bioverge: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Chimera Bioengineering: Current equity holder in publicly-traded company. Usmani: Sanofi: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; EdoPharma: Consultancy; GSK: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; Array BioPharma: Consultancy, Research Funding; SkylineDX: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Seattle Genetics: 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; Abbvie: Consultancy. OffLabel Disclosure: Magrolimab is an investigational therapy