Prediction of Malignant Cell Infiltration Patterns with Texture Features of Biopsy-Correlated Positron Emission Tomography of Osteolytic Lesions in Multiple Myeloma

Abstract Introduction: Osteolytic bone disease represents a severe clinical presentation of multiple myeloma (MM), as MM cells infiltrate the bone marrow throughout the skeleton, forming tumors, activating bone-resorbing osteoclasts, and impeding bone-depositing osteoblast activity. The extent of osteolytic lesions encompassing the skeleton influences the severity of disease for patients, with severe lesions leading to skeletal-related events (SREs). MM cell infiltration into the bone marrow gradually increases with disease progression; however, the distribution of myeloma cells within the bone and marrow is heterogenous. Standard of care imaging modalities used to monitor the number, size, and extent of bone destruction of lesions include whole-body magnetic resonance imaging (MRI), whole-body low-dose computed tomography (CT), and positron emission tomography with CT (PET/CT). With the use of computational methodologies, imaging textural features can be calculated from PET. In this prospective study, we aim to find PET textural features that will correlate with histological evaluation of myeloma cell infiltration patterns of osteolytic lesions and un-guided bone marrow biopsies in MM patients. Patients and Methods: 40 patients were enrolled in this prospective study with either newly diagnosed multiple myeloma (n=16, 40%) or relapse/refractory multiple myeloma (n= 24, 60%). Whole-body PET/CT imaging was performed on all patients as part of MM standard of care, after which CT-guided biopsies were taken from patient osteolytic lesions identified by imaging and in bone marrow biopsies. 68 biopsies were evaluated by an expert hematopathologist, of which 59 had analyzable imaging studies in the respective areas. Myeloma cell infiltration patterns in all biopsies were classified as interstitial (n=23, 41.8%), nodular (n=19, 34.6%), or packed (n=13, 23.6%), as described by Andrulis et al. (2014). PET lesion and bone marrow segmentation was performed on the Medical Imaging Interaction Toolkit (MITK) and 72 textural features were calculated using the PyRadiomics extension (van Griethuysen et al. 2017) for 3D Slicer 4.11 (Fedorov et al. 2012). PET quantitative features were calculated using the PET IndiC extension from 3D Slicer (QIICR (2015b)). Statistical analysis was performed via GraphPad Prism 9 (GraphPad Software, San Diego, California USA) and the Radiomics Analysis with R (RadAR, Benelli et al. 2020) package in the RStudio environment (RStudio Team (2020). RStudio: Integrated Development for R. RStudio, PBC, Boston, MA). Results: Lesion biopsy samples predominantly favored packed infiltration pattern (53.6%) over interstitial (21.4%) or nodular (25%), while staging/follow-up bone marrow biopsies predominantly favored interstitial or nodular patterns (47.5% and 35.0%, respectively) compared to packed (22.5%). Two-way analysis of variance (ANOVA) tests was performed to compare imaging features between biopsy infiltration patterns and also between disease status of patients. The first order uniformity (p<0.05) was able to discern between interstitial, nodular, or packed infiltration for all biopsies and textural features from the Gray Level Co-Occurrence Matrix (GLCM) Correlation and Joint Entropy were accurately able to discern between interstitial and either nodular or packed infiltration patterns for all biopsies (p<0.01). Within lesion biopsies specifically (n=25), first order uniformity, kurtosis, skewness, and textural features Joint Entropy and Dependence Non-Uniformity could discern between MM cell infiltration patterns (p<0.05). PET quantitative SUV statistics did not show any significant separation between infiltration patterns. First order, textural, and PET SUV quantitative features could not distinguish disease status of the patient. Conclusions: In this preliminary study, we demonstrate a correlation between textural imaging features and pathological findings within the bone marrow and osteolytic lesions of MM patients. This correlation illustrates a potential link between computational imaging features to predict pathological findings in patients with MM. Further expansion of this study with genomic, flow cytometry, and multimodality imaging data could lead to the generation of computational modeling of the pathophysiology of osteolytic lesions in MM and a reduction in the need for invasive bone marrow and lesion biopsies. Figure 1 Figure 1. Disclosures Merz: Takeda: Honoraria; onkowissen.de: Honoraria; Amgen: Honoraria; BMS: Honoraria; Celgene: Honoraria; Sanofi: Honoraria; Janssen: Honoraria; GSK: Honoraria; Hexal: Honoraria. McCarthy: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Juno: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hillengass: Beijing Life Oasis Public Service Center: Speakers Bureau; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Axxess Network: Membership on an entity's Board of Directors or advisory committees; Beijing Medical Award Foundation: Speakers Bureau; Adaptive: 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; Skyline: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Curio Science: Speakers Bureau.

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Asymptomatic Amyloidosis at the Time of Diagnostic Bone Marrow Biopsy in Newly Diagnosed Patients with Multiple Myeloma and Smoldering Multiple Myeloma.

Blood ◽

10.1182/blood.v114.22.2803.2803 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2803-2803

Author(s):

Sergio Siragusa ◽

William Morice ◽

Morie A Gertz ◽

Robert Kyle ◽

Philip R. Greipp ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Congo Red ◽

Newly Diagnosed ◽

Advisory Committees ◽

Bone Marrow Biopsies ◽

Smoldering Multiple Myeloma ◽

High Level

Abstract Abstract 2803 Poster Board II-779 Background. The rate of asymptomatic amyloidosis (asym-amyloidosis) detected in patients with newly diagnosed multiple myeloma (MM) or smoldering multiple myeloma (SMM) is unknown. This topic is significant because unrecognized AL may be associated with increased mortality may change the patient's management. The objective of the present investigation was to evaluate the number and clinical significance of asym-amyloidosis in MM and SM patients at the time of the diagnostic bone marrow (BM) biopsy for MM. Materials and Methods. The study population was selected from the Mayo Clinic Dysproteinemia database and consisted of consecutive patients with an established diagnosis of MM or SMM without recognition of symptomatic AL. Bone marrow biopsies at diagnosis of MM or SMM were retrospectively stained with Congo Red and reviewed by a single pathologist. A patient was considered to have asym-amyloid if Congo Red staining with apple green birefringence was found. Results. Biopsies from 144 (M 84, F 59) patients were evaluated: 77 had a diagnosis of MM and 67 of SMM. The median age was 59 (range 26-84) years. No differences were found regarding hemoglobin, platelets, prothrombin time, serum and urine proteins, serum albumin, alkaline phosphate, creatinine and β2-microglobulin among MM and SMM patients. At a median follow-up 76 months (range 0-216), 32% patients were alive, 65% dead and 2.7% lost to follow-up. Immunoglobulin isotypes were as follows: 96/144 (67%) had IgG 23/144 (16%) IgA, 12/144 (8%) had light chain only, 1/77 (1%) had IgD, none had IgM and 12/144 (8%) had biclonal or indeterminate; 84/144 (58%) were κ restricted. The presence of amyloid was found in only 2 cases (1%, 95% CI – 0.6 to 3.2), 1 in MM and 1 in SMM group. Neither of these patients had or developed signs or symptoms suggestive of organ involvement by amyloid. Among the 142 other patients without amyloid deposition in their index bone marrow, 1 (0.7%, 95% CI -0.6 to 2.0) developed symptomatic AL after 119 months of follow-up. Characteristics of these three patients are shown in table 1. Conclusions. We found only 2 cases (1%) of amyloidosis in the 144 cases of MM or SMM. Our estimates are lower than the rates which have been reported by others, perhaps because of our high level of suspicion for amyloid at our Amyloidosis Center. These data do not support the need for searching for asym-amyloidosis in patients with newly diagnosed MM or SMM as long as they have no clinical features of AL. Disclosures: Off Label Use: Hydroxyurea use in myelofibrosis. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Witzig:Novartis: Research Funding. Kumar:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Architecture of Sample Preparation and Data Governance of Immuno-Genomic Data Collected from Bone Marrow and Peripheral Blood Samples Obtained from Multiple Myeloma Patients

Blood ◽

10.1182/blood-2020-142882 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 17-18

Author(s):

Shaadi Mehr ◽

Daniel Auclair ◽

Mark Hamilton ◽

Leon Rozenblit ◽

Hearn Jay Cho ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Peripheral Blood ◽

Large Scale ◽

Mass Cytometry ◽

Data Governance ◽

Advisory Committees ◽

Blood Samples ◽

Data Files

Abstract: Title: Architecture of sample preparation and data governance of Immuno-genomic data collected from bone marrow and peripheral blood samples obtained from multiple myeloma patients In multiple myeloma (MM), the interactions between malignant plasma cells and the bone marrow microenvironment is crucial to fully understand tumor development, disease progression, and response to therapy. The core challenge in understanding those interactions has been the establishment of a standard process and a standard model for handling the data quality workflow and the underlying data models. Here we present the Platform (Figure 1), an integrated data flow architecture designed to create data inventory and process tracking protocols for multi-dimensional and multi-technology immune data files. This system has been designed to inventory and track peripheral blood and bone marrow samples from multiple myeloma subjects submitted for immune analysis under the MMRF Immune Atlas initiative (figure 2), and the processing and storage of Single Cell RNA-seq (scRNA-seq) and Mass Cytometry time-of-flight (CyTOF) data files derived from these immune analyses. While these methods have been previously applied on both tumor and immune populations in MM [2,3], this level of multi-institutional and multi-technology is unique. The Cloud Immune-Precision platform contains standardized protocols and bioinformatics workflows for the identification and categorization of immune cell populations and functional states based upon scRNA-seq gene signatures (ref: Bioinformatics manuscript in submission) and CyTOF protein signatures. Upon further expansion, it will contain high dimensional scRNAseq and CyTOF immune data from both bone marrow and peripheral blood samples from myeloma patients enrolled in the Multiple Myeloma Research Foundation (MMRF) CoMMpass study (NCT01454297) [1] (Figure 3). The architecture covers the automation of data governance protocols, data transformation and ETL model developments that will create an immune proteomic and profiling database and its integration into clinical and genomics databases: e.g. the MMRF CoMMpass clinical trial. This large-scale data integration will establish a cutting-edge Immune-Precision central platform supporting large scale, immune-focused advanced analytics in multiple myeloma patients. This platform will allow researchers to interrogate the relationships between immune transcriptomic and proteomic signatures and tumor genomic features, and their impact on clinical outcomes, to aid in the optimization of therapy and therapeutic sequencing. Furthermore, this platform also promotes the potential to (further) elucidate the mechanisms-of-action of approved and experimental myeloma therapies, drive biomarker discovery, and identify new targets for drug discovery. Figure 1: Cloud Immune-Precision Platform (Integrated data flow architecture designed to create data inventory and process tracking protocols for multi-dimensional and multi-technology immune data files) Figure 2: Sample tracking process architecture Figure 3: Data file creation and repository process tracking References: 1- Settino, Marzia et al. "MMRF-CoMMpass Data Integration and Analysis for Identifying Prognostic Markers." Computational Science - ICCS 2020: 20th International Conference, Amsterdam, The Netherlands, June 3-5, 2020, Proceedings, Part III vol. 12139 564-571. 22 May. 2020, doi:10.1007/978-3-030-50420-5_42 2- Ledergor, Guy et al. "Single cell dissection of plasma cell heterogeneity in symptomatic and asymptomatic myeloma." Nature medicine vol. 24,12 (2018): 1867-1876. doi:10.1038/s41591-018-0269-2 3- Hansmann, Leo et al. "Mass cytometry analysis shows that a novel memory phenotype B cell is expanded in multiple myeloma." Cancer immunology research vol. 3,6 (2015): 650-60. doi:10.1158/2326-6066.CIR-14-0236-T Figure 1 Disclosures Bhasin: Canomiiks Inc: Current equity holder in private company, Other: Co-Founder. Dhodapkar:Amgen: Membership on an entity's Board of Directors or advisory committees, Other; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Other; Janssen: Membership on an entity's Board of Directors or advisory committees, Other; Roche/Genentech: Membership on an entity's Board of Directors or advisory committees, Other; Lava Therapeutics: Membership on an entity's Board of Directors or advisory committees, Other; Kite: Membership on an entity's Board of Directors or advisory committees, Other.

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Multiple Myeloma Cells Induce Lipolysis in Adipocytes and Uptake Fatty Acids through Fatty Acid Transporter Proteins

Blood ◽

10.1182/blood-2020-142625 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 41-42

Author(s):

Cristina Panaroni ◽

Keertik Fulzele ◽

Tomoaki Mori ◽

Chukwuamaka Onyewadume ◽

Noopur S. Raje

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Fatty Acid ◽

Board Of Directors ◽

Metabolic Reprogramming ◽

Glycerol Production ◽

Advisory Committees ◽

Myeloma Cells ◽

Long Chain

Multiple myeloma (MM) originates in the bone marrow where adipocytes occupy 65% of the cellular volume in a typical myeloma patient. Cancer associated adipocytes support the initiation, progression, and survival of solid tumors via mechanisms including adipokine secretion, modulation of the tumor microenvironment, and metabolic reprogramming of cancer cells. Although MM cells are surrounded by abundant bone marrow adipocytes (BMAd), the nature of their interaction remains unclear. Recent studies have elucidated the role of BMAds in supporting the survival of MM cells, in part, through secreted adiponectin. Increased fatty acid (FA) metabolism may result in metabolic reprogramming of cancer cells impacting their growth and survival. Here, we hypothesize that MM cells extract FA from adipocytes for their growth. We first characterized mesenchymal stem cells (MSCs) from MGUS, smoldering MM (SMM), and newly diagnosed MM (NDMM) patients by flow cytometry analysis. MSCs showed significant increase in Pref1, leptin receptor and perilipin A, suggesting increased adipogenic commitment. MSCs from healthy donors (HD), MGUS, SMM, and NDMM patients were induced to differentiate into adipocytes and then co-cultured with human MM MM.1S cells. After 72 hr of co-culture, CyQUANT assay demonstrated significant increase in proliferation of MM.1S cells in the presence of BMAd from HD; this was further increased in the presence of BMAd from MGUS/SMM and NDMM. These data suggest that the BMAd support the growth of MM cells and this effect is more pronounced in patient derived BMAd. A PCR-array targeting lipid metabolism on BM fat aspirates showed significant deregulation of genes involved in FA synthesis and lipolysis. Taken together, our data suggest that BMAd in MM patients are altered to further support the aggressive expansion of MM cells. The proliferative-supportive role of adipocytes was further validated in co-culture of OP9 murine BM stromal preadipocytes with 5TGM1 murine MM cells. To study the bidirectional interaction of MM/ BMAd, mature OP9 adipocytes were co-cultured with 5TGM1 or human OPM2 MM cells for 24 hr. Intracellular lipid droplets were labelled with Deep Red LipidTox stain. The lipid droplet sizes were significantly decreased in the presence of both 5TGM1 and OPM2 cells compared to OP9 alone. The decrease in lipid size suggested that MM cells may induce lipolysis in adipocytes. Indeed, 24hr co-culture of 5TGM1 cells with OP9 mature adipocytes significantly increased lipolysis 3-fold as measured by glycerol secretion in conditioned media. Co-culture of OP9 adipocytes with other MM cell lines of human origin, MM.1S, INA6, KMS-12 PE, and OPM2 also significantly increased the glycerol production as much as 4-fold. Taken together these data indicate that MM cells induce lipolysis in adipocytes. In contrast, treatment of 5TGM1 cells with synthetic catecholamine isoproterenol did not induce lipolysis, or glycerol production, indicating lack of triglyceride storage. Next, we hypothesized that the free FAs released from adipocytes are taken up by MM cells for various biological processes. To test this, 5TGM1, MM.1S and OPM2 cells were incubated with BODIPY-C12 and BODIPY-C16, the BODIPY-fluorophore labelled 12-carbon and 16-carbon long chain FA. All MM cells showed saturated uptake of the FA within 10 minutes suggesting that MM cells have efficient FA transporters. To confirm this uptake, unstained 5TGM1, OPM2 and KMS12 PE cells were co-cultured with the LipidTox-labelled OP9 mature adipocytes. After 24 hours, flow cytometric analysis showed LipidTox signal in MM cells. These data demonstrate that FAs released by MM induced adipocyte lipolysis are taken up by MM cells. Long-chain FAs such as BODIPY-C12 and BODIPY-C16 are transported into cells through FA transporter protein (FATP) family of lipid transporters. We therefore analyzed patient samples which showed that CD138+ plasmacells and myeloma cells expressed high levels of FATP1 and FATP4 whereas, their expression was absent in lineage-sibling T-cells. Moreover, pretreatment with Lipofermata, a FATP inhibitor, was able to decrease the uptake of BODIPY-C12 and -C16 in 5TGM1 cells. Taken together, our data show that myeloma cells induce lipolysis in adipocytes and the released free FAs are then uptaken by myeloma cells through FATPs. Inhibiting myeloma cell induced lipolysis or uptake of FA through FATPs may be a potential anti-tumor strategy. Disclosures Fulzele: FORMA Therapeutics, Inc: Current Employment, Other: Shareholder of Forma Therapeutics. Raje:Amgen: Consultancy; bluebird bio: Consultancy, Research Funding; Caribou: Consultancy, Membership on an entity's Board of Directors or advisory committees; Immuneel: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Immuneel: Consultancy; Janssen: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy.

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Phase II Trial of the Combination of Ixazomib, Lenalidomide, and Dexamethasone in High-Risk Smoldering Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-117871 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 804-804 ◽

Cited By ~ 7

Author(s):

Mark Bustoros ◽

Chia-jen Liu ◽

Kaitlen Reyes ◽

Kalvis Hornburg ◽

Kathleen Guimond ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

High Risk ◽

Disease Progression ◽

Board Of Directors ◽

Rna Sequencing ◽

Research Funding ◽

Response Rate ◽

Advisory Committees ◽

Equity Ownership

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

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Correlation of Hemophagocytosis with Clinical Criteria of Hemophagocytic Lymphohistiocytosis and Recommendations for Screening Bone Marrow Samples in Adult Patients

Blood ◽

10.1182/blood-2020-139246 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 37-38

Author(s):

Caroline Wilson ◽

Wei-i Lee ◽

Matthew Cook ◽

Lillian Smyth ◽

Dipti Talaulikar

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Hemophagocytic Lymphohistiocytosis ◽

Research Funding ◽

Interobserver Variability ◽

Laboratory Data ◽

Adult Patients ◽

Advisory Committees ◽

Bone Marrow Biopsies ◽

Immunohistochemical Stain

Introduction Hemophagocytic lymphohistiocytosis (HLH) is a rare condition resulting from a dysregulated inflammatory response. It can prove difficult to diagnose and portends a poor prognosis. Bone marrow (BM) biopsy is an easily accessible test that is often used to identify the presence of hemophagocytosis and assess for underlying malignancy. Currently there are no evidence-based guidelines on the reporting of hemophagocytosis on BM biopsy and no reports of a correlation between hemophagocytosis with the clinical diagnostic criteria for HLH. We therefore aimed to assess if the amount of hemophagocytosis identified in the BM biopsy correlates with HLH-2004 criteria. Secondary aims were to evaluate inter-observer variability in reporting hemophagocytosis, and to formulate recommendations for screening in BM specimens. Method A retrospective review of bone marrow biopsies from adult patients under investigation for HLH was undertaken independently by 2 hematopathologists who were blinded to the original biopsy report. Relevant clinical and laboratory data was extracted from medical records. The average number of actively hemophagocytic cells in each slide prepared from BM aspirates were quantified into 0, 1, 2-4 and ≥5. On trephine samples, hemophagocytosis was reported as either 'present' or 'absent', with the assistance of the CD68 immunohistochemical stain. Cases with discordance pertaining to the degree of hemophagocytosis were reviewed by both assessors to reach a consensus. Results Sixty-two specimens from 59 patients were available for assessment. An underlying hematological condition was identified in 34 cases (58%). The most common underlying hematological condition was lymphoma, found in 15 cases (25%). There was a significant association between the amount of hemophagocytosis identified on the aspirate samples and the number of HLH-2004 criteria met (p<0.05). In patients where hemophagocytosis was present (n=31), there was a significant correlation between the amount of hemophagocytosis and ferritin levels (p<0.05). Interobserver variability was present in 63% of cases. Based on our review, we make the following recommendations for reporting of hemophagocytosis in the BM samples:> 1. Count only macrophages ingesting intact hemopoietic cells. W2. Quantify the average number of active histiocytes per aspirate slide. W3. Count histiocytes away from particles where the cellular outline is clear. W4. Avoid counting conglomerates of histiocytes where the cellular margins are indistinct W5. On the aspirate specimen, assess for hemophagocytosis on both the trail and squash preparations. W6. Delineating hemophagocytosis on trephine samples is difficult without the use of a CD68 immunohistochemical stain. Interestingly, a study by Ho et al found no association between the BM histologic findings and the probability of hemophagocytosis (Ho et al, American Journal of Clinical Pathology, 2014). This difference highlights the need for standardised reporting of BM specimens. Conclusion Our findings indicate that the amount of hemophagocytosis present on BM samples correlates with the number of HLH-2004 criteria met. We found marked interobserver variability which we anticipate can be rectified with our recommendations on the reporting of hemophagocytosis. Disclosures Talaulikar: Takeda: Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Phase 1/2 Study of Elotuzumab in Combination with Bortezomib in Patients with Multiple Myeloma with One to Three Prior Therapies: Interim Results.

Blood ◽

10.1182/blood.v114.22.3876.3876 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3876-3876 ◽

Cited By ~ 1

Author(s):

Andrzej J Jakubowiak ◽

William Bensinger ◽

David Siegel ◽

Todd M. Zimmerman ◽

Jan M. Van Tornout ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Clinical Response ◽

Board Of Directors ◽

Research Funding ◽

Mononuclear Cells ◽

Phase 1 ◽

Surface Glycoprotein ◽

Advisory Committees ◽

Cell Surface Glycoprotein

Abstract Abstract 3876 Poster Board III-812 Background Elotuzumab is a humanized monoclonal IgG1 antibody directed against CS1, a cell surface glycoprotein, which is highly and uniformly expressed in multiple myeloma (MM). In mouse xenograft models of MM, elotuzumab demonstrated significantly enhanced anti-tumor activity when combined with bortezomib compared to bortezomib alone (Van Rhee et al., Mol. Cancer Ther., in press, 2009). This phase 1/2 trial will determine the maximum tolerated dose (MTD), overall safety, pharmacokinetics (PK) and clinical response of elotuzumab in combination with bortezomib in patients with relapsed MM following 1-3 prior therapies. Methods The study consists of 4 escalating cohorts of elotuzumab (2.5 mg/kg to 20 mg/kg) administered on Days 1 and 11 and bortezomib (1.3 mg/m2) administered on Days 1, 4, 8 and 11 of a 21-day cycle. Patients with progressive disease at the end of Cycle 2 or 3 also receive oral dexamethasone (20 mg) on Days 1, 2, 4, 5, 8, 9, 11 and 12 of each subsequent cycle. Patients with stable disease or better at the end of 4 cycles will continue treatment for 6 or more cycles unless withdrawn earlier due to unexpected toxicity or disease progression. Key entry criteria: age ≥ 18 years; confirmed diagnosis of MM and documentation of 1 to 3 prior therapies; measurable disease M-protein component in serum and/or in urine; and no prior bortezomib treatment within 2 weeks of first dose. Results To date, a total of 16 MM patients with a median age of 64 years have been enrolled in the study. The median time from initial diagnosis of MM was 3.5 years and patients had received a median of 2 prior MM treatments. Patients have been treated in four cohorts; 3 each in 2.5, 5 and 10 mg/kg elotuzumab cohorts, and 7 in the 20 mg/kg elotuzumab cohort. No dose limiting toxicity (DLT) was observed during the first cycle of the study and the MTD was not established. Five SAEs have been reported in four patients in later treatment cycles; two events, chest pain and gastroenteritis, occurring in one patient, were considered elotuzumab-related. Other SAEs include grade 3 sepsis, vomiting, pneumonia and grade 2 dehydration. The most common AEs reported include Grade 1-3 diarrhea, constipation, nausea, fatigue, thrombocytopenia, neutropenia, anemia and peripheral neuropathy. The best clinical response (EBMT criteria) for the 16 patients who have received at least two cycles of treatment is shown in the table below. Preliminary PK analysis suggests a serum half-life of 10-11 days at higher doses (10 and 20 mg/kg). Preliminary analysis of peripheral blood mononuclear cells and bone marrow of patients on study indicates that objective responses in the study correlate well with complete saturation of CS1 sites by elotuzumab on bone marrow plasma and NK cells. Conclusions The combination of elotuzumab with bortezomib has a manageable adverse event profile and shows promising preliminary efficacy with ≥PR in 44% and ≥MR in 75% of all enrolled patients. Accrual is ongoing in the expanded 20 mg/kg cohort. Updated safety, efficacy, and PK data will be presented at the meeting. Disclosures: Jakubowiak: Millennium: 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; Centocor Ortho Biotech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Exelixis: 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. Off Label Use: Bortezomib in combination with elotuzumab for the treatment of relapsed/refractory multiple myeloma. Bensinger:Millennium: Membership on an entity's Board of Directors or advisory committees. Siegel:Millennium: Speakers Bureau; Celgene: Speakers Bureau. Zimmerman:Millennium: Speakers Bureau; Centecor: Speakers Bureau. Van Tornout:BMS: Employment. Zhao:Facet Biotech: Employment. Singhal:Facet Biotech: Employment. Anderson:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Dual Targeting of -TORC1 and -TORC2 as a New Strategy In the Treatment of Multiple Myeloma

Blood ◽

10.1182/blood.v116.21.133.133 ◽

2010 ◽

Vol 116 (21) ◽

pp. 133-133 ◽

Cited By ~ 2

Author(s):

Patricia Maiso ◽

AbdelKareem Azab ◽

Yang Liu ◽

Yong Zhang ◽

Feda Azab ◽

...

Keyword(s):

Cell Cycle ◽

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Cell Lines ◽

Mechanism Of Action ◽

Plasma Cells ◽

Bone Marrow Microenvironment ◽

Advisory Committees

Abstract Abstract 133 Introduction: Mammalian target of rapamycin (mTOR) is a downstream serine/threonine kinase of the PI3K/Akt pathway that integrates signals from the tumor microenvironment such as cytokines and growth factors, nutrients and stresses to regulate multiple cellular processes, including translation, autophagy, metabolism, growth, motility and survival. Mechanistically, mTOR operates in two distinct multi-protein complexes, TORC1 and TORC2. Activation of TORC1 leads to the phosphorylation of p70S6 kinase and 4E-BP1, while activation of TORC2 regulates phosphorylation of Akt and other AGC kinases. In multiple myeloma (MM), PI3K/Akt plays an essential role enhancing cell growth and survival and is activated by the loss of the tumor suppressor gene PTEN and by the bone marrow microenvironment. Rapamycin analogues such as RAD001 and CCI-779 have been tested in clinical trials in MM. Their efficacy as single agents is modest, but when used in combination, they show higher responses. However, total inhibition of Akt and 4E-BP1 signaling requires inactivation of both complexes TORC1 and TORC2. Consequently, there is a need for novel inhibitors that can target mTOR in both signaling complexes. In this study we have evaluated the role of TORC1 and TORC2 in MM and the activity and mechanism of action of INK128, a novel, potent, selective and orally active small molecule TORC1/2 kinase inhibitor. Methods: Nine different MM cell lines and BM samples from MM patients were used in the study. The mechanism of action was investigated by MTT, Annexin V, cell cycle analysis, Western-blotting and siRNA assays. For the in vivo analyses, Luc+/GFP+ MM.1S cells (2 × 106/mouse) were injected into the tail vein of 30 SCID mice and tumor progression was detected by bioluminescence imaging. Nanofluidic proteomic immunoassays were performed in selected tumors. Results: To examine activation of the mTOR pathway in MM, we performed kinase activity assays and protein analyses of mTOR complexes and its downstream targets in nine MM cell lines. We found mTOR, Akt, pS6R and 4E-BP1 are constitutively activated in all cell lines tested independently of the status of Deptor, PTEN, and PI3K. All cell lines expressed either Raptor, Rictor or both; excepting H929 and U266LR7 which were negative for both of them. Moreover, primary plasma cells from several MM patients highly expressed pS6R while normal cells were negative for this protein. We found that INK128 and rapamycin effectively suppressed phosphorylation of p6SR, but only INK128 was able to decrease phosphorylation of 4E-BP1. We observed that INK128 fully suppressed cell viability in a dose and time dependent manner, but rapamycin reached a plateau in efficacy at ± 60%. The IC50 of INK128 was in the range of 7.5–30 nM in the eight cell lines tested. Similar results were observed in freshly isolated plasma cells from MM patients. Besides the induction of apoptosis and cell cycle arrest, INK128 was more potent than rapamycin to induce autophagy, and only INK128 was able to induce PARP and Caspases 3, 8 and 9 cleavage. In the bone marrow microenvironment context, INK128 inhibited the proliferation of MM cells and decreased the p4E-BP1 induction. Importantly, treatment with rapamycin under such conditions did not affect cell proliferation. INK128 also showed a significantly greater effect inhibiting cell adhesion to fibronectin OPM2 MM1S, BMSCs and HUVECs compared to rapamycin. These results were confirmed in vivo. Oral daily treatment of NK128 (1.0 mg/kg) decreased tumor growth and improved survival of mice implanted with MM1S. Conclusion: Dual inhibition of TORC1 and TORC2 represent a new and promising approach in the treatment of MM and its microenvironment. The ability of INK128 to inhibit both TORC1 and TORC2 strongly supports the potential use of this compound in MM patients. Disclosures: Anderson: Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ghobrial:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

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Multiple Myeloma In Complete Remission After Autologous Stem Cell Transplantation: Impact of Bone Marrow Plasma Cell Assessment by Conventional Morphology on Disease Progression

Blood ◽

10.1182/blood.v116.21.2946.2946 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2946-2946

Author(s):

Carlos Fernández de Larrea ◽

Natalia Tovar ◽

María Rozman ◽

Laura Rosiñol ◽

Juan I. Aróstegui ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Stem Cell ◽

Complete Remission ◽

Board Of Directors ◽

Research Funding ◽

Bone Marrow Aspirate ◽

Advisory Committees ◽

Bone Marrow Plasma ◽

Serum And Urine

Abstract Abstract 2946 Background: The achievement of complete remission (CR) is the crucial step for a long-lasting response and prolonged survival after autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM). The European Group for Blood and Marrow Transplantation (EBMT) criteria for CR include the negativity of serum and urine immunofixation (IFE) and less than 5% of bone marrow plasma cells (BMPCs). Additionally, the International Myeloma Working Group (IMWG) has even proposed a stringent CR category, which requires to rule out the clonal nature of the BMPCs. However, few studies have addressed this issue in patients with MM and negative IFE. The aim of the present study was to determine the impact of plasma cell count in the bone marrow aspirate on the long-term outcome of patients with MM with negative IFE after ASCT. Methods: Thirty-five patients (16M/19F; median age at ASCT 55 years, range 26–68) with MM who underwent ASCT from March 1994 to December 2008, were studied. All patients had achieved a negative serum and urine IFE after high dose therapy with melphalan-based regimens. Bone marrow aspirate was performed when negative serum and urine IFE was achieved and at least three months from ASCT (median 3.24 months). The analysis was based on microscopic revision for May-Grünwald-Giemsa stained bone marrow smears performed according to standard procedures. BMPC percentage was calculated independently by two observers counting 500 bone marrow total nucleated cells in random areas from two different slides (1000 cells on each patient). Results: Median BMPCs percentage was 0.8 (range 0.1–5.8). Only two patients had more than 3% BPMCs. These results are in contrast with a recent report from the Mayo Clinic group, where 14% of the patients with MM and negative IFE had 5% or more BMPCs. In univariate Cox-model regression analysis, the number of BMPCs significantly correlated with progression-free survival (PFS)(p=0.021) with no impact on overall survival (OS)(p=0.92). This statistical significance on PFS was retained in the multivariate analysis, when baseline prognostic factors such as age, hemoglobin level, serum creatinine, β2-microglobulin and Durie-Salmon stage were added to the model (p=0.003). To establish the best predictive cut-off for progression and survival, a receptor-operator curve (ROC) analysis was developed. It showed the value of 1.5% BMPCs, with a sensitivity of 53%, specificity of 90% and area under the curve of 0.66 for predicting progression. Ten patients had more than 1.5% BMPC, and 25 equal or less than 1.5% BMPC. Median PFS was 8.5 years (CI 95% 2.6 to 14.3) and was not reached in patients with ≤1.5% BMPCs versus 3.1 years in patients with >1.5% BMPCs, with a hazard ratio probability to progression of 3.02 (CI 95% 1.18 to 9.71)(p=0.016) in the group with more than 1.5% of BMPCs (Figure 1). Median OS was not reached in patients with ≤1.5% compared with a median of 9.7 years in those with more than 1.5% BMPCs (p=0.195) (Figure 2). It is likely that serological CR with very low percentage of BMPCs (i.e. ≤1.5%) is equivalent to negative MRD assessed by MFC or molecular studies. In fact, all 8 patients in continued CR between 9 and 16 years beyond ASCT (“operational cures”) are in the group with ≤1.5% BMPCs, while all patients in the group with >1.5% BPMC have relapsed within the first 9 years from ASCT (Figure 1). Conclusion: The percentage of BMPCs in patients with MM in CR after ASCT is a strong predictor of progression. Bone marrow morphology examination is an easy, inexpensive, and non-time consuming test and it should be the first step in the estimation of the residual tumor mass in patients with MM in CR after ASCT. Disclosures: Rosiñol: Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cibeira:Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Blade:Janssen-Cilag: Honoraria, 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, Research Funding.

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Dynamic Regulation of the Level of Hypoxia In the Bone Marrow Regulates Cell Dissemination In Multiple Myeloma

Blood ◽

10.1182/blood.v116.21.4035.4035 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4035-4035

Author(s):

Abdel Kareem A. Azab ◽

Phong Quang ◽

Feda Azab ◽

Brian Thompson ◽

Patricia Maiso ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Tumor Progression ◽

Board Of Directors ◽

Tumor Burden ◽

Secondary Antibody ◽

Advisory Committees ◽

Hypoxic Conditions ◽

Mild Hypoxia

Abstract Abstract 4035 INTRODUCTION: The interaction of multiple myeloma (MM) cells with the bone marrow (BM) microenvironment plays a crucial role in MM pathogenesis, implying that progression of MM occurs through continuous interaction between the BM and MM cells, which controls the ability of MM cells to egress out of the BM and home into new BM niches. We have previously shown that the CXCR4/SDF1 axis as well as Rho GTPases downstream of the receptor was important for chemotaxis, adhesion, homing and egress of MM cells. However, the driving force for MM cells to leave the BM and metastasize to other BM sites is not well understood. Regions of severe oxygen deprivation (hypoxia) arise in tumors due to rapid cell division and are associated with poor patient prognosis, cell motility, associated angiogenesis and metastasis. In this study, we tested the role of hypoxia in the dissemination of MM cells in vivo, as well as regulation of the retention/egress of MM cells in and out of the BM. METHODS: To test the effect of hypoxia on induction of MM egress, MM1s-GFP+/Luc+ cells were injected into 12 SCID mice, and then mice with different stages of tumor development (based on the tumor size detected by bioluminescence) were treated with the hypoxia marker pimonidazole. Blood was drawn and BM was obtained from the femur. Mononuclear cells were then fixed, permeabilized, and stained with antibodies against pimonidazole, followed with an APC- secondary antibody, PE-mouse-anti-human CXCR4, and anti-cadherin antibody followed by an Alexa-Fluor-594 secondary antibody. MM cells in BM and peripheral blood were identified by gating on cells with high GFP signal. To confirm the effects of severe hypoxia found in vivo compared to physiologic mild hypoxia found in the BM, we tested the effect of mild hypoxic conditions (6% O2) and severe hypoxic conditions (0.5% O2) on MM expression of cadherins and CXCR4, as well on functional adhesion of MM cells to stromal cells and chemotaxis. RESULTS: Twelve mice with different stages of MM tumor progression were used. A bi-phasic correlation between tumor progression and the percent of hypoxic cells in BM was found, showing that severe hypoxic conditions in the BM correlated with tumor burden. The correlation between the tumor burden and the number of circulating cells was not linear; however, a direct linear correlation was observed between the number of circulating MM cells and hypoxia in the BM. Moreover, hypoxia in BM correlated directly with the expression of CXCR4 and negatively correlated with the expression of cadherins in MM cells isolated from the BM. To test the effect of the severe hypoxic conditions induced by tumor progression compared to mild hypoxic conditions found physiologically in the BM, we tested the effect of 0.5% O2 (severe hypoxia) and 6% O2 (mild hypoxia) compared to normoxia (21%) on MM cell adhesion to BMSCs, as well as on chemotaxis in response to SDF1, as well as expression of CXCR4 and cadherins. We found that severe hypoxic conditions decreased MM expression of cadherins and adhesion to BMSCs, as well as increased expression of CXCR4 and chemotaxis to SDF1 compared to cells in normoxia. In contrast, mild hypoxic conditions did not alter the expression of CXCR4 and cadherins, adhesion of MM cells to BMSCs, or chemotaxis of MM to SDF1 compared to normoxic cells. CONCLUSION: Hypoxia in the BM directly correlates with the number of circulating MM cells, and with changes in expression of cadherins and CXCR4 in vivo. Severe hypoxic conditions, but not mild hypoxic conditions, induce hypoxic responses in MM cells. Based on these findings, further studies to manipulate hypoxia in order to regulate tumor dissemination as a therapeutic strategy in MM are warranted. Disclosures: Anderson: Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ghobrial:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

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Targeting Brouton's Tyrosine Kinase with PCI-32765 Blocks Growth and Survival of Multiple Myeloma and Waldenström Macroglobulinemia Via Potent Inhibition of Osteoclastogenesis, Cytokines/Chemokine Secretion, and Myeloma Stem-Like Cells in the Bone Marrow Microenvironment

Blood ◽

10.1182/blood.v118.21.883.883 ◽

2011 ◽

Vol 118 (21) ◽

pp. 883-883

Author(s):

Yu-Tzu Tai ◽

Betty Y Chang ◽

Sun-Young Kong ◽

Mariateresa Fulciniti ◽

Guang Yang ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Tyrosine Kinase ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Advisory Committees ◽

Growth And Survival ◽

Equity Ownership ◽

Trap Staining

Abstract Abstract 883 Specific expression of Bruton's tyrosine kinase (Btk) in osteoclasts (OC), but not osteoblasts (OB), suggests its role in regulating osteoclastogenesis. Although Btk is critical in B cell maturation and myeloid function, it has not been characterized in plasma cell malignancies including multiple myeloma (MM) and Waldenström Macroglobulinemia (WM). We here investigate effects of PCI-32765, an oral, potent, and selective Btk inhibitor with promising clinical activity in B-cell malignancies, on OC differentiation and function within MM bone marrow (BM) microenvironment, as well as on MM and WM cancer cells. We further define molecular targets of Btk signaling cascade in OCs and MM in the BM milieu. In CD14+ OC precursor cells, RANKL and M-CSF stimulate phosphorylation of Btk in a time-dependent fashion; conversely, PCI-32765 abrogates RANKL/M-CSF-induced activation of Btk and downstream PLCγ2. Importantly, PCI-32765 decreased number of multinucleated OC (>3 nuclei) by tartrate-resistant acid phosphatase (TRAP) staining and the secretion of TRAP5b (ED50 = 17 nM), a specific mature OC marker. It increased size of OCs and number of nuclei per OC, with significantly defective bone resorption activity as evidenced by diminished pit formation on dentine slices. Moreover, lack of effect of Dexamethasone on OC activity was overcome by combination of Dexamethasone with PCI-32765. PCI-32765 significantly reduced cytokine and chemokine secretion from OC cultures, including MIP1α, MIP1β, IL-8, TGFβ1, RANTES, APRIL, SDF-1, and activin A (ED50 = 0.1–0.48 nM). It potently decreased IL-6, SDF-1, MIP1α, MIP1β, and M-CSF in CD138-negative cell cultures from active MM patients, associated with decreased TRAP staining in a dose-dependent manner. In MM and WM cells, immunoblotting analysis confirmed a higher Btk expression in CD138+ cells from majority of MM patients (4 out of 5 samples) than MM cell lines (5 out of 9 cell lines), whereas microarray analysis demonstrated a higher expression of Btk and its downstream signaling components in WM cells than in CD19+ normal bone marrow cells. PCI-32765 significantly inhibits SDF-1-induced adhesion and migration of MM cells. It further blocked cytokine expression (MIP1a, MIP-1β) at mRNA level in MM and WM tumor cells, correlated with inhibition of Btk-mediated pPLCγ2, pERK and NF-kB activation. Importantly, PCI-32765 inhibited growth and survival triggered by IL-6 and coculture with BM stromal cells (BMSCs) or OCs in IL-6-dependent INA6 and ANBL6 MM cells. Furthermore, myeloma stem-like cells express Btk and PCI-32765 (10–100 nM) blocks their abilities to form colonies from MM patients (n=5). In contrast, PCI-32765 has no adverse effects on Btk-negative BMSCs and OBs, as well as Btk-expressing dendritic cells. Finally, oral administration of PCI-32765 (12 mg/kg) in mice significantly suppresses MM cell growth (p< 0.03) and MM cell-induced osteolysis on implanted human bone chips in a humanized myeloma (SCID-hu) model. Together, these results provide compelling evidence to target Btk in the BM microenvironment against MM and WM., strongly supporting clinical trials of PCI-32765 to improve patient outcome in MM and WM. Disclosures: Chang: Pharmacyclics Inc: Employment. Buggy:Pharmacyclics, Inc.: Employment, Equity Ownership. Elias:Pharmacyclics Inc: Consultancy. Treon:Millennium: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Genentech: Honoraria. Richardson:Millennium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees; Novartis: 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. Munshi:Millennium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Anderson:Millennium Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Onyx: Consultancy; Merck: Consultancy; Bristol-Myers Squibb: Consultancy; Actelion: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

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