Overcoming Drug Resistance in Myeloma By Synchronized Delivery of Therapeutic and Bone Marrow Disrupting Agents By Nanoparticles Targeting Tumor-Associated Endothelium

Abstract Proteasome inhibitors (PIs) have improved the treatment of multiple myeloma (MM) and prolonged patient survival, but several challenges remain to overcome drug-resistance and toxicity. Bone marrow microenvironment (BMM) drives tumor progression and PIs-resistance in MM; and agents that inhibit the interaction between MM and BMM have been shown to re-sensitize MM cells to therapy. However, the synchronized in vivo delivery of BMM-targeting agents with PIs has been a challenge so far. Nanoparticles offer a valuable platform to encapsulate drugs, and if functionalized, they can facilitate specific delivery to tumor, thus improving treatment efficacy and reducing off-target effects. Within the BMM, the endothelium plays a relevant tumor promoting role. By analyzing the expression of an array of markers in normal and in MM-related endothelium, we found high levels of P-selectin expression on MM-activated endothelial cells (ECs) than normal cells and on ECs collected from the BM of either MM patients or MM-bearing mice compared to their respectively healthy BMMNCs. We next sought to develop lipid nanoparticles (LNPs) targeting the MM-related endothelium, loaded with both PI and BMM-targeting agent for synchronized delivery and reversal of the BMM-induced drug resistance. At this aim, we developed targeted LNPs towards P-selectin by decorating their surface with P-selectin-glycoprotein-ligand-1 (PSGL-1). PSGL-1-targeted LNPs showed specific binding to recombinant P-selectin than identically non-targeted particles, and to MM-associated endothelium compared to healthy endothelium, both in vitro and in vivo. To reverse BMM-induced resistance, LNPs were loaded with bortezomib (BTZ) together with a BMM disrupting agent, ROCK-inhibitor (Y-27632) that inhibits the downstream signaling of the RhoA GTPase pathway, known to be instrumental to the interaction of MM cells with BMM. Consequently, we tested the effect of synchronized delivery of BTZ and Y-27632 in the same LNP on MM cell survival in co-culture with the BMM in vitro. While Y-27632-loaded LNPs did not affect cell proliferation, LNPs loaded with both Y-27632 and BTZ enhanced responsiveness of MM cells to BTZ, compared to BTZ-loaded LNPs, thus overcoming the BMM-induced resistance. Mechanistically, we observed more significant inhibition of PI3K and MAPK signaling, decrease of pRb and up-regulation of p21 and induction of pro-apoptotic pathway (caspase-3, caspase-9 and PARP) by drug-loaded LNPs, compared to free drugs. In addition, drug-loaded LNPs were able to decrease adhesion and impair the migration of MM cells to ECs. We also investigated the in vivo efficacy of BTZ/Y-27632-loaded PSGL-1-targeted LNPs in a humanized murine model of MM. The synchronized delivery of both agents using dual drug-loaded PSGL-1-targeted LNPs delayed the MM tumor progression and prolonged survival significantly more than all the controls. The synchronized delivery of both agents using dual drug-loaded PSGL-1-targeted LNPs delayed the MM tumor progression and prolonged survival significantly more than all the controls (vehicle, BTZ and Y-27632 alone or in combination as free drugs, or encapsulated in non-targeted or in PSGL-1-targeted LNPs) demonstrating that both P-selectin targeting and combination of Y-27632 with BTZ reverses the BMM-induced drug resistance and enhances the efficacy of therapy in vivo. Altogether, our data demonstrate the ability of PSGL-1-decorated LNPs to specifically target MM-BMM; to efficiently encapsulate and deliver drugs to tumor tissue; to overcome BMM-induced drug resistance in vitro and in vivo, to reduce tumor growth and prolong overall survival. This study provides the preclinical basis for future clinical trials using MM-BMM-targeted nanomedicine able to enhance the effect of PIs or other drugs for the treatment of MM. Disclosures Roccaro: GILEAD: Research Funding; AMGEN: Other: Advisory Board. Vij:Karyopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jansson: 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, Research Funding; Bristol-Myers Squibb: 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Azab:Cellatrix LLC: Equity Ownership, Other: Founder and owner; Targeted Therapeutics LLC: Equity Ownership, Other: Founder and owner; Ach Oncology: Research Funding; Glycomimetics: Research Funding.

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Biodistribution and Efficacy of L-Annamycin in a Novel Imageable AML Mouse Model

Blood ◽

10.1182/blood-2019-131977 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5150-5150

Author(s):

Rafal Zielinski ◽

Krzysztof Grela ◽

Stanislaw Skora ◽

Rodrigo Jacamo ◽

Izabela Fokt ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Residual Disease ◽

Advisory Committees ◽

Two Photon Microscopy ◽

Two Photon ◽

Equity Ownership

Annamycin (Ann) is an anti-tumoral anthracycline whose anti-leukemia activity is relatively unaffected by P-glycoprotein-related multidrug resistance. Unlike for the related doxorubicin (DOX), Ann accumulates in multidrug resistant cell lines, which is accompanied by DNA damage and apoptosis. In preclinical toxicology studies, in contrast to DOX, free Ann displayed a greatly reduced cardiotoxicity, while L-Ann appeared to be non-cardiotoxic. A liposomal formulation of Ann, termed L-Annamycin (L-Ann), is currently evaluated in patients with acute myeloid leukemia (AML). Anti-leukemia activity of Ann was demonstrated in several leukemia models as judged by circulating blast cytoreduction and extension of overall survival. However, the efficacy of L-Ann in the microenvironment of the bone marrow and other organ tissues remains unclear. In the current study, we assessed the anti-AML efficacy of Ann in a novel AML model that allows visualizing the dynamics of individual AML cells in vivo by two-photon microscopy. In this model, mouse AML cells bearing the MLL/ENL-FLT3/ITD[p53-/-] mutations co-express high levels of the cyan fluorescent protein mTurquoise2. Upon intravenous infusion of several tens of thousands cells into syngeneic immunocompetent C57BL6 mice, lethal AML disease reliably develops within 2 weeks. Using host mice expressing appropriate fluorescence reporter genes, the bright cyan fluorescence enables sensitive intravital imaging of individual AML cells in the context of organ architecture. Using this model in Thy1-RFP reporter mice expressing red fluorescence in all organ tissues with the blood flow marked by BSA-AF647 fluorescence, we evaluated AML cellularity reduction in the bone marrow and other organs after a single dose of L-Ann as well as in response to chronic treatment. In addition, we assessed the localization of the surviving AML cells at a high spatial resolution. We evaluated the in vivo organ biodistribution of intravenously infused L-Ann in C57BL6 mice by flow cytometry and two-photon microscopy based on the intrinsic fluorescence of the drug. In addition, we visualized the intracellular compartmentalization of L-Ann using confocal microscopy. Consistent with in vitro findings, we observed a rapid and deep reduction of AML blasts in the peripheral blood after a single dose of L-Ann in a dose-dependent manner (1-4 mg/kg). This reduction was strongly correlated with prolongation of animal survival from 14 days (vehicle) to 37 days (L-Ann 4 mg/kg once weekly started on day 10). In vitro and intravital microscopy revealed a distinct pattern of L-Ann distribution in organ tissues, which correlated in part with the local index of AML cellularity reduction and residual disease localization. Interestingly, in addition to the expected uptake of Ann in the cell's nucleus, Ann was also accumulated in the cytosol of the cells. This bi-compartmental intracellular distribution pattern contrasted with the nuclear-only localization of DOX. Administration of L-Ann early in the course of AML resulted in occasional complete responses some of which associated with resistance to AML re-challenge, suggesting capacity for anti-AML immune memory induction. This study confirms the efficacy of the drug in the model setting of syngeneic, immune-competent AML. Besides reinforcing the rationale for further development of Annamycin in AML, this study demonstrates a highly advantageous AML mouse model that is highly informative in studies of AML pharmacology, minimum residual disease (MRD), microenvironment and immunology. Disclosures Fokt: Moleculin Biotech, Inc.: Equity Ownership, Research Funding. Andreeff:Oncoceutics: Equity Ownership; Senti Bio: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Consultancy, Patents & Royalties: Patents licensed, royalty bearing, Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy; Amgen: Consultancy; AstaZeneca: Consultancy; 6 Dimensions Capital: Consultancy; Reata: Equity Ownership; Aptose: Equity Ownership; Eutropics: Equity Ownership; Leukemia Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; NCI-RDCRN (Rare Disease Cliln Network): Membership on an entity's Board of Directors or advisory committees; CLL Foundation: Membership on an entity's Board of Directors or advisory committees; BiolineRx: Membership on an entity's Board of Directors or advisory committees; German Research Council: Membership on an entity's Board of Directors or advisory committees; NCI-CTEP: Membership on an entity's Board of Directors or advisory committees; Cancer UK: Membership on an entity's Board of Directors or advisory committees; Oncolyze: Equity Ownership; Breast Cancer Research Foundation: Research Funding; CPRIT: Research Funding; NIH/NCI: Research Funding; Center for Drug Research & Development: Membership on an entity's Board of Directors or advisory committees. Priebe:Moleculin Biotech, Inc.: Consultancy, Equity Ownership, Research Funding. Zal:VueBio.com: Equity Ownership; BioLineRx: Research Funding; Daiichi-Sankyo: Research Funding; Moleculin Biotech, Inc.: Research Funding; NIH-CTEP: Research Funding; CPRIT: Research Funding; NIH/NCI: Research Funding.

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BCL-2 Inhibitor Venetoclax (ABT-199) and MEK Inhibitor GDC-0973 Synergise to Target AML Progenitors and Overcome Drug Resistance with the Use of PET Scanning in a Mouse Model of HR-MDS to Monitor Response to Treatment

Blood ◽

10.1182/blood-2018-99-114212 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5497-5497 ◽

Cited By ~ 2

Author(s):

Rose Ann Padua ◽

Laure Sarda-Mantel ◽

Mathieu Chiquet ◽

Claire Kappel ◽

Patricia Krief ◽

...

Keyword(s):

Bone Marrow ◽

Drug Resistance ◽

Board Of Directors ◽

Research Funding ◽

Colony Growth ◽

Response To Treatment ◽

Advisory Committees ◽

Cytotoxic Effects ◽

Pet Scanning ◽

Equity Ownership

Abstract Introduction: Targeted drugs are needed for HR-MDS/AML, particularly in elderly patients and Venetoclax, approved for some CLL, gives promising results in elderly AML. Assays to predict response to treatment may enable us to deliver personalized treatment. We sought to determine the most informative assay to predict response; viability assays can directly measure the effects of reagents on growth. Progenitor assays can potentially determine if the reagents can target diseased primitive cells. PET scanning can be used to follow response to treatment. Methods: Peripheral blood (PB) or bone marrow (BM) from 7 MDS/AML patients were incubated in a) no treatment, b) ABT-199 (1 µM) (Abbvie), c) GDC-0973 (1 µM) (Genentech) or d) ABT-199+GDC-0973 (1 µM of each) and assessed for viability using the MTT assay (n=2); cell death followed using the Incucyte® Zoom System (Essen Bioscience) (n=2) or methocult progenitor assays (Stem Cell Technologies) (n=4). Having shown that RAS:BCL-2 co-localization correlated with prognosis in MDS/AML patients (Leuk Res 37:312-9, 2013), immunofluorescence was undertaken. A micro PET device dedicated to mice was used to measure BM blast proliferation. After injection of 18F-FLT(a thymidine analogue) in mice untreated (n=7) or ABT-199 (75mg/kg)+GDC-0973(10mg/kg) treated (n=5) normal FVB/N, HR-MDS mice treated with vehicle (n=4), 2-month old HR-MDS before (n=5) and 3-month old before (n=4) and after ABT-199 (75mg/kg)+GDC-0973(10mg/kg) treatment (n=8), PET imaging was performed (Inveon Siemens Medical Systems), analyzed for signal and quantified. Results: Patient details and results are summarized on Table 1. Using the MTT assay 2 PB patient samples were found to be sensitive to ABT-199 treatment (Figure 1A, AS, p=0.00042 and YA, 0.00002) and more sensitive to the combination compared to untreated (AS, p=0.00007 and YA, 0.000003). With the incucyte the BM of one patient (AE) was found to be resistant to both ABT-199 and GDC-0973, but sensitive to the combination (Figure 1B). PB and BM from patient JA were assayed for apoptosis with the incucyte and were found to be sensitive to ABT-199 with increased apoptosis, resistant to GDC-0973 with decreased apoptosis and sensitive to the combination. Four bone marrow samples were tested in the 4 conditions using the progenitor assay (Figure 1C). Three patients were sensitive to GDC-0973, inhibiting any colony formation and the fourth had reduced colony numbers. In this assay patient JA appeared to be sensitive to GDC-0973 treatment whereas the incucyte assay scored this sample to be resistant to apoptosis; thus the cytotoxic effects of GDC-0973 may not be via apoptopsis. As the progenitor assay is likely to score the primitive disease population, this assay may prove more informative than the others without prior selection. One patient (DH) was clearly resistant to ABT-199, whereas the other three (JA, CB and FL) had reduced colony growth. All patients were sensitive to the combination treatment and inhibited colony growth. The RAS:BCL-2 co-localization in the PB revealed no complex in either the Mito or PM upon treatment with ABT-199 alone and some localization in the Mito with GDC-0973. With both ABT-199 and GDC-0973, there were hardly any cells confirming the cytotoxic effects of the combination. As we have previously shown that PM co-localization of the complex is associated with drug resistance (Blood 130:2613, 2017Suppl), we used the combination on our HR-MDS mouse model, where the complex co-localizes in the PM and followed the mice by PET scanning (Figure 1D). Weak signal was visualized in the femurs of untreated and ABT-199+GDC-0973 treated FVB/N mice (FBR 1.17+/-0.34 and 1.02+/-0.08 respectively). Mild PET signal was seen in the femurs of 2 month-old HR-MDS mice, (FBR 1.79+/-0.98). Intense PET signal was seen in the femurs and proximal humerus of HR-MDS mice treated with vehicle (3 month-old, FBR=2.35+/-1.32). Low PET signals were seen in the femurs of 5/8 HR-MDS mice treated with ABT-199+GDC-0973 (FBR=1.93+/-0.84). FBRs of the 3 groups of HR-MDS mice were significantly higher than those of FBV/N groups. Conclusion: Combined Venetoclax (ABT-199) and GDC-0973 targets MDS/AML progenitors and can potentially overcome drug resistance with the disruption of the RAS:BCL-2 complex. Bone marrow disease progression in HR-MDS mice can be monitored with 18F-FLT-PET imaging; PET data shows that the combination slows down disease progression. Disclosures Padua: Abbvie: Research Funding; Genentech: Research Funding. Giraudier:Novartis: Research Funding. Konopleva:Stemline Therapeutics: Research Funding. Andreeff:Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Reata: Equity Ownership; Celgene: Consultancy; Jazz Pharma: Consultancy; Oncolyze: Equity Ownership; Amgen: Consultancy, Research Funding; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; SentiBio: Equity Ownership; Astra Zeneca: Research Funding.

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Targeting Wnt/β-Catenin and BCL-2, Two Critical Survival Factors, Synergistically Induces Apoptosis in AML Via Rac1-Mediated MCL-1 Inhibition

Blood ◽

10.1182/blood-2018-99-118367 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1442-1442

Author(s):

Xiangmeng Wang ◽

Po Yee Mak ◽

Wencai Ma ◽

Xiaoping Su ◽

Hong Mu ◽

...

Keyword(s):

Progenitor Cells ◽

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Single Agent ◽

Advisory Committees ◽

Equity Ownership ◽

Critical Survival

Abstract Wnt/β-catenin signaling regulates self-renewal and proliferation of AML cells and is critical in AML initiation and progression. Overexpression of β-catenin is associated with poor prognosis. We previously reported that inhibition of Wnt/β-catenin signaling by C-82, a selective inhibitor of β-catenin/CBP, exerts anti-leukemia activity and synergistically potentiates FLT3 inhibitors in FLT3-mutated AML cells and stem/progenitor cells in vitro and in vivo (Jiang X et al., Clin Cancer Res, 2018, 24:2417). BCL-2 is a critical survival factor for AML cells and stem/progenitor cells and ABT-199 (Venetoclax), a selective BCL-2 inhibitor, has shown clinical activity in various hematological malignancies. However, when used alone, its efficacy in AML is limited. We and others have reported that ABT-199 can induce drug resistance by upregulating MCL-1, another key survival protein for AML stem/progenitor cells (Pan R et al., Cancer Cell 2017, 32:748; Lin KH et al, Sci Rep. 2016, 6:27696). We performed RNA Microarrays in OCI-AML3 cells treated with C-82, ABT-199, or the combination and found that both C-82 and the combination downregulated multiple genes, including Rac1. It was recently reported that inhibition of Rac1 by the pharmacological Rac1 inhibitor ZINC69391 decreased MCL-1 expression in AML cell line HL-60 cells (Cabrera M et al, Oncotarget. 2017, 8:98509). We therefore hypothesized that inhibiting β-catenin by C-82 may potentiate BCL-2 inhibitor ABT-199 via downregulating Rac1/MCL-1. To investigate the effects of simultaneously targeting β-catenin and BCL-2, we treated AML cell lines and primary patient samples with C-82 and ABT-199 and found that inhibition of Wnt/β-catenin signaling significantly enhanced the potency of ABT-199 in AML cell lines, even when AML cells were co-cultured with mesenchymal stromal cells (MSCs). The combination of C-82 and ABT-199 also synergistically killed primary AML cells (P<0.001 vs control, C-82, and ABT-199) in 10 out of 11 samples (CI=0.394±0.063, n=10). This synergy was also shown when AML cells were co-cultured with MSCs (P<0.001 vs control, C-82, and ABT-199) in all 11 samples (CI=0.390±0.065, n=11). Importantly, the combination also synergistically killed CD34+ AML stem/progenitor cells cultured alone or co-cultured with MSCs. To examine the effect of C-82 and ABT-199 combination in vivo, we generated a patient-derived xenograft (PDX) model from an AML patient who had mutations in NPM1, FLT3 (FLT3-ITD), TET2, DNMT3A, and WT1 genes and a complex karyotype. The combination synergistically killed the PDX cells in vitro even under MSC co-culture conditions. After PDX cells had engrafted in NSG (NOD-SCID IL2Rgnull) mice, the mice were randomized into 4 groups (n=10/group) and treated with vehicle, C-82 (80 mg/kg, daily i.p injection), ABT-199 (100 mg/kg, daily oral gavage), or the combination for 30 days. Results showed that all treatments decreased circulating blasts (P=0.009 for C-82, P<0.0001 for ABT-199 and the combination) and that the combination was more effective than each single agent (P<0.001 vs C-82 or ABT-199) at 2 weeks of therapy. The combination also significantly decreased the leukemia burden in mouse spleens compared with controls (P=0.0046) and single agent treated groups (P=0.032 or P=0.020 vs C-82 or ABT-199, respectively) at the end of the treatment. However, the combination did not prolong survival time, likely in part due to toxicity. Dose modifications are ongoing. These results suggest that targeting Wnt/β-catenin and BCL-2, both essential for AML cell and stem cell survival, has synergistic activity via Rac1-mediated MCL-1 inhibition and could be developed into a novel combinatorial therapy for AML. Disclosures Andreeff: SentiBio: Equity Ownership; Oncolyze: Equity Ownership; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Consultancy; Amgen: Consultancy, Research Funding; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Reata: Equity Ownership; Astra Zeneca: Research Funding; Celgene: Consultancy; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer . Carter:novartis: Research Funding; AstraZeneca: Research Funding.

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LNA Anti-MicroRNA-155: A Novel Therapeutic Strategy in Waldenstrom Macroglobulinemia and Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood.v118.21.2728.2728 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2728-2728

Author(s):

Yong Zhang ◽

Christopher P. Rombaoa ◽

Aldo M Roccaro ◽

Susanna Obad ◽

Oliver Broom ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Tumor Cells ◽

Stromal Cells ◽

Research Funding ◽

Mrna Levels ◽

Advisory Committees ◽

Qrt Pcr

Abstract Abstract 2728 Background. We and others have previously demonstrated that primary Waldenstrom's Macroglobulinemia (WM) and Chronic lymphocytic leukemia (CLL) cells show increased expression of microRNA-155 (miR-155), suggesting a role in regulating pathogenesis and tumor progression of these diseases. However, developing therapeutic agents that specifically target miRNAs has been hampered by the lack of appropriate delivery of small RNA inhibitors into tumor cells. We tested the effect of a novel LNA (locked nucleic acid)-modified anti-miR-155 in WM and CLL. Methods. WM and CLL cells, both cell lines (BCWM.1; MEC.1) and primary tumor cells; BCWM.1 Luc+ cells; and primary WM bone marrow (BM) stromal cells were used. WM and CLL cells were treated with antisense LNA anti-miR-155 or LNA scramble oligonucleotide. Efficiency of delivering FAM-labeled LNA into cells was determined by flow cytometry. Survival and cell proliferation were assessed by MTT and thymidine uptake assay, respectively. Synergistic effects of LNA with bortezomib were detected on BCWM.1 or MEC1 cells. Co-culture of BCWM.1 or MEC1 cells with WM bone marrow stromal cells was performed to better define the effect of the LNA-anti-miR155 in the context of the bone marrow microenvironment. miR-155 levels were detected in stromal cells from WM patients by qPCR. Co-culture of BCWM.1 or MEC1 cells with either wild-type or miR155−/− mice BM stromal cells was examined after LNA treatment. Gene expression profiling analysis was performed on BCWM.1 cells treated with either LNA anti-miR-155 or scramble control. miR-155 target gene candidates were predicted by TargetScan software. mRNA levels of miR-155, and its known target genes or gene candidates were detected by qRT-PCR. A microRNA luciferase reporter assay was used to determine whether miR-155 target candidates could be directly regulated by miR-155. mRNA levels of miR-155 targets were detected by qRT-PCR from primary WM or CLL cells treated with LNA. The activity of the LNA-anti-miR-155 was also detected in vivo using bioluminescence imaging and mRNA levels of miR-155 targets were detected by qRT-PCR ex vivo. Efficiency of introducing the FAM-labeled LNA into mice BM cells was determined by flow cytometry 1 week or 2 weeks after intravenous injection. Results. The efficiency of delivering LNA oligos into both WM and CLL-derived cell lines and primary samples was higher than 90%. LNA antimiR-155 reduced proliferation of WM and CLL-derived cell lines by 30–50%, as compared to LNA scramble control. In contrast, LNA antimiR-155 didn't exert significant cytotoxicity in BCWM.1 or MEC.1. LNA synergistically decreased BCWM.1 or MEC1 cell growth co-treated with bortezomib and decreased BCWM.1 or MEC1 cell growth co-cultured with WM BM stromal cells in vitro. A higher level of miR-155 was found in WM BM stromal cells compared to normal ones. LNA decreased BCWM.1 or MEC1 cell growth when co-cultured with BM stromal cells from miR155−/− mice compared with wild-type. We demonstrated increased expression of miR-155-known targeted genes, including CEBPβ, SOCS1, SMAD5, and several novel target candidates including MAFB, SH3PXD2A, and SHANK2, in WM cells upon LNA anti-miR-155 treatment. These target candidates were confirmed to be directly regulated by miR-155 using a luciferase reporter assay. mRNA levels of miR-155 targets were upregulated by 1.5–2 fold at 48 hr after direct incubation of the LNA with primary WM or CLL samples, indicating efficient delivery and biologic effect of the LNA in cells. Moreover, this LNA showed significant in vivo activity by inhibiting WM cell proliferation in a disseminated xenograft mouse model. Upregulation of miR-155 targeted genes were confirmed ex vivo, in WM cells isolated from the BM of treated mice compared to control. Mice BM cells were FAM positive 1 or 2 weeks after injection indicating efficient delivery of FAM-labeled LNA into cells in vivo. Summary. A novel LNA (locked nucleic acid)-modified anti-miR against miR-155 could be highly efficiently delivered into tumor cells in vivo in the bone marrow microenvironment. Anti-WM activity of LNA anti-miR-155 was confirmed both in vitro and in vivo and anti-CLL activity was confirmed in vitro. Novel miR-155 direct target genes including MAFB, SH3PXD2A, and SHANK2 were identified. These findings will help to design individualized clinical trials for WM and CLL patients with elevated levels of miR-155 in their tumor cells. Disclosures: Roccaro: Roche:. Obad:Santaris Pharma: Employment. Broom:Electroporation: Employment. Kauppinen:Santaris Pharma: Employment. Brown:Calistoga: Consultancy, Research Funding; Celgene: Honoraria, Research Funding; Genzyme: Research Funding; GSK: Research Funding. Ghobrial:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees.

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3D-Tissue Engineered Bone Marrow (3DTEBM) Culture Retrospectively Predicts Treatment Clinical Outcomes of Multiple Myeloma Patients

Blood ◽

10.1182/blood-2018-99-118888 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1987-1987

Author(s):

Amanda Jeske ◽

Feda Azab ◽

Pilar De La Puente ◽

Barbara Muz ◽

Justin King ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Ex Vivo ◽

In Vitro Models ◽

Advisory Committees ◽

Treatment Plans ◽

Equity Ownership

Abstract Background: Multiple Myeloma (MM) is the second most common hematological malignancy, and continues to be a fatal disease even with the development of novel therapies. Despite promising preclinical data in standard tissue culture models, most drugs fail in clinical trials and show lower efficacy in patients. This highlights the discrepancy between the current in vitro models, the pathophysiology of the disease in the patients, and the urgent need for better in vitro models for drug development and improved prediction of efficacy in patients. We have previously developed a patient-derived 3D-Tissue Engineered Bone Marrow (3DTEBM) culture model, which showed superior properties for proliferation of primary MM cells ex vivo, and better recapitulated drug resistance. The long-term goal of this study is to use the 3DTEBM model as a tool to perform drug screens on BM aspirates of MM patients and prospectively predict the efficacy of different therapies in individual patients, and help treatment providers develop personalized treatment plans for each individual patient. In the current study, we used the 3DTEBM model to, retrospectively, predict clinical responses of MM patients to therapy, as a proof of concept. Methods: We used whole-BM, viably frozen tissue banked samples from 20 MM patients with clear clinical response patterns of complete remission, and either very good partial response (sensitive) or progressive disease (non-sensitive). The BM aspirates were used to develop a 3DTEBM that represents each individual patient. The patient-derived 3DTEBM cultures were treated ex vivo with the same therapeutic regimen that the patient received in the clinic for 3 days. The treatment ex vivo was based on combinations at different concentrations which mimic the steady state concentrations (Css) of each drug. The efficacy of the treatment ex vivo was evaluated by digestion of the 3DTEBM matrix, extraction of the cells, and analysis for prevalence of MM cells in the treatment groups compared to the non-treated controls. Patients were defined "sensitive" if the effect reached 50% killing in the range of 10xCss. The ex vivo sensitivity data was then correlated with the clinical response outcomes. Results: We found that the 3DTEBM was predictive in approximately 80% of the cases (in about 85% of the combination therapy cases, and in about 70% of the single therapy cases). Broken down by individual drug, it was predictive in 80% of the cases treated with Bortezomib, 78% Lenalidomide, 84% Dexamethasone, 100% Daratumumab, 50% Carfilzomib, 50% Pomalidomide, and 100% Doxorubicin. Conclusions: The 3DTEBM is a more pathophysiologically relevant model which predicts clinical efficacy of drugs in multiple myeloma patients, retrospectively. This data provides the bases for future studies which will examine the ability of the 3DTEBM model to predict treatment efficacy, prospectively, for development of personalized treatment plans in individual multiple myeloma patients. Disclosures Jeske: Cellatrix LLC: Employment. Azab:Cellatrix LLC: Employment. De La Puente:Cellatrix LLC: Other: Co-founder. Vij:Jazz Pharmaceuticals: 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, Research Funding; Karyopharma: 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, Research Funding; Jansson: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Azab:Ach Oncology: Research Funding; Cellatrix LLC: Equity Ownership, Other: Founder and owner; Glycomimetics: Research Funding; Targeted Therapeutics LLC: Equity Ownership, Other: Founder and owner.

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L-Stereoisomer RNA Oligonucleotide Anti-SDF-1 (Nox-A12) Disrupts the Interaction of Multiple Myeloma Cells with the Bone Marrow Milieu In Vivo, Leading to Enhanced Sensitivity to Bortezomib

Blood ◽

10.1182/blood.v118.21.887.887 ◽

2011 ◽

Vol 118 (21) ◽

pp. 887-887

Author(s):

Aldo M Roccaro ◽

Antonio Sacco ◽

Phong Quang ◽

AbdelKareem Azab ◽

Patricia Maiso ◽

...

Keyword(s):

Bone Marrow ◽

Confocal Microscopy ◽

Board Of Directors ◽

Tumor Cells ◽

Research Funding ◽

Ex Vivo ◽

In Vivo Confocal Microscopy ◽

Advisory Committees

Abstract Abstract 887 Background. Stomal-cell-derived factor 1 (SDF-1) is known to be involved in bone marrow (BM) engrafment for malignant tumor cells, including CXCR4 expressing multiple myeloma (MM) cells. We hypothesized that de-adhesion of MM cells from the surrounding BM milieu through SDF-1 inhibition will enhance MM sensitivity to therapeutic agents. We therefore tested NOX-A12, a high affinity l-oligonucleotide (Spiegelmer) binder to SDF-1in MM, looking at its ability to modulate MM cell tumor growth and MM cell homing to the BM in vivo and in vitro. Methods. Bone marrow (BM) co-localization of MM tumor cells with SDF-1 expressing BM niches has been tested in vivo by using immunoimaging and in vivo confocal microscopy. MM.1S/GFP+ cells and AlexaFluor633-conjugated anti-SDF-1 monoclonal antibody were used. Detection of mobilized MM-GFP+ cells ex vivo has been performed by flow cytometry. In vivo homing and in vivo tumor growth of MM cells (MM.1S-GFP+/luc+) were assessed by using in vivo confocal microscopy and in vivo bioluminescence detection, in SCID mice treated with 1) vehicle; 2) NOX-A12; 3) bortezomib; 4) NOX-A12 followed by bortezomib. DNA synthesis and adhesion of MM cells in the context of NOX-A12 (50–200nM) treated primary MM BM stromal cells (BMSCs), in presence or absence of bortezomib (2.5–5nM), were tested by thymidine uptake and adhesion in vitro assay, respectively. Synergism was calculated by using CalcuSyn software (combination index: C.I. according to Chou-Talalay method). Results. We first showed that SDF-1 co-localizes in the same bone marrow niches of growth of MM tumor cells in vivo. NOX-A12 induced a dose-dependent de-adhesion of MM cells from the BM stromal cells in vitro. These findings were corroborated and validated in vivo: NOX-A12 induced MM cell mobilization from the BM to the peripheral blood (PB) as shown ex vivo, by reduced percentage of MM cells in the BM and increased number of MM cells within the PB of mice treated with NOX-A12 vs. control (BM: 57% vs. 45%; PB: 2.7% vs. 15%). We next showed that NOX-A12-dependent de-adhesion of MM cells from BMSCs lead to enhanced MM cell sensitivity to bortezomib, as shown in vitro, where a synergistic effect between NOX-A12 (50–100 nM) and bortezomib (2.5–5 nM) was observed (C.I.: all between 0.57 and 0.76). These findings were validated in vivo: tumor burden detected by BLI was similar between NOX-A12- and control mice whereas bortezomib-treated mice showed significant reduction in tumor progression compared to the control (P<.05); importantly significant reduction of tumor burden in those mice treated with sequential administration of NOX-A12 followed by bortezomib was observed as compared to bortezomib alone treated mice (P <.05). Similarly, NOX-A12 + bortezomib combination induced significant inhibition of MM cell homing in vivo, as shown by in vivo confocal microscopy, as compared to bortezomib used as single agent. Conclusion. Our data demonstrate that the SDF-1 inhibiting Spiegelmer NOX-A12 disrupts the interaction of MM cells with the BM milieu both in vitro and in vivo, thus resulting in enhanced sensitivity to bortezomib. Disclosures: Roccaro: Roche:. Kruschinski:Noxxon Pharma AG: Employment. Ghobrial:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Advisory Board, Research Funding.

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Hypoxia Promotes Dissemination of Multiple Myeloma Through Acquisition of Endothelial to Mesenchymal Transition (EMT) Features

Blood ◽

10.1182/blood.v118.21.471.471 ◽

2011 ◽

Vol 118 (21) ◽

pp. 471-471

Author(s):

Abdel Kareem Azab ◽

Jinsong Hu ◽

Phong Quang ◽

Feda Azab ◽

Costas Pitsillides ◽

...

Keyword(s):

Flow Cytometry ◽

Tumor Progression ◽

Board Of Directors ◽

Research Funding ◽

Tumor Burden ◽

Advisory Committees ◽

Mesenchymal Transition ◽

E Cadherin

Abstract Abstract 471 Multiple myeloma (MM) is characterized by widespread dissemination of the MM cells at diagnosis associated with multiple focal bone lesions, implying (re)circulation of MM cells into the peripheral blood and (re)entrance or homing into new sites of the BM. However, the driving force for MM cells to leave the BM, egress, and home to new BM niches is still not well understood. Hypoxia (low oxygen) in solid tumors was shown to promote metastasis in solid tumors through activation of proteins involved in the endothelial to mesenchymal Transition (EMT). In this study, we hypothesized that MM tumor progression induces hypoxic conditions, which in turn activates EMT related proteins and promotes metastasis of MM cells. To test this hypothesis, we examined levels of hypoxia in MM cells at different stages of tumor progression in vivo in two animal models: the first by injecting MM1s cell to SCID mice, and the second by injecting 5T33MM cells to C57BL/KaLwRijHsd mice. Hypoxic markers were examined using flow cytometry and immunohistochemistry. We found that tumor progression induced hypoxia in both the MM cells and the tumor microenvironment. Similarly, hypoxia induced genes (HIF1a, HIF1b, HIF2b, CREBBP, HYOU1, VEGF1, HIF1a-inhibitory protein) were increased in MM patients (n=68) compared to plasma cells from healthy donors (n=14). Using flow cytometry we found that the number of circulating MM cells increased with the progression; however, the correlation was observed in late stages of the progression but not in the early stages. A better direct correlation was achieved with the hypoxic state of the MM cells in the BM. Circulating MM cells were more hypoxic that MM cells in the BM (especially at low tumor burden). Moreover, we found that the level of hypoxia in MM cells in the PB did not correlate with the hypoxia in the BM. Next, we tested the mechanism in which hypoxia induces cell egress. We found that MM cells isolated from MM patients have higher gene expression of EMT inducing proteins (E-cadherin, SNAIL, FOXC2, TGFb1) in parallel to a decrease of expression in E-cadherin, and we confirmed the downregulation of E-cadherin expression in correlation with the increase of hypoxia in MM cell and cells in the BM microenvironment in vivo. Culturing MM cells under hypoxic conditions increased the expression of HIF1a and HIF2a. In parallel, hypoxia induced acquisition of EMT related features including downregulation of E-cadherin, upregulation of SNAIL, and inhibition of GSK3b. In addition, hypoxia decreased the adhesion of MM cells to stromal cells. To complete the metastatic process after egress, MM cells need to home to new sites in the BM. Therefore we investigated the effect of hypoxia on expression of CXCR4, chemotaxis and homing of MM cells to the BM. Using flow cytometry we found a direct correlation between hypoxia and the expression of CXCR4 in MM cells in vivo using the SCID-MM1s model. These results were confirmed in vitro, where hypoxia increased the expression of CXCR4 at protein and mRNA levels in MM cells. Moreover, the expression of CXCR4 in MM cells isolated from the PB was higher than cells isolated from the BM especially at low tumor burden, correlating with higher hypoxic state of the circulating tumor cells. Functionally, hypoxia increased the chemotaxis of MM cells towards SDF1a in vitro and, using in vivo confocal microscopy, it was shown to accelerate the homing of MM cells to the BM in vivo. To demonstrate that the chemotaxis and homing were CXCR4 dependent, we treated the hypoxic MM cells with AMD3100 (a CXCR4 inhibitor) and showed that it inhibited chemotaxis in vitro and homing of MM to the BM in vivo. In conclusion, we demonstrate that tumor progression induces hypoxia in the MM cells and in the BM microenvironment. Hypoxia activates EMT-related machinery in MM cells, decreases expression of E-cadherin and consequently decreased the adhesion of MM cells to the BM, and enhance egress of MM cells to the circulation. In parallel, hypoxia increases the expression of CXCR4, and consequently increased the migration and homing of MM cells in from the peripheral blood to the BM. Further studies to manipulate hypoxia in order to regulate tumor dissemination as a therapeutic strategy are warranted. Disclosures: Roccaro: Roche: . Kung:Novartis Pharmaceuticals: Consultancy, Research Funding. Ghobrial:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Noxxon: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Inhibition of Sialylation Impairs Adhesion on Madcam-1 and E-Selectin and Sensitize Multiple Myeloma Cells to Bortezomib in a Xenograft Mouse Model

Blood ◽

10.1182/blood-2018-99-118361 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3204-3204

Author(s):

Alessandro Natoni ◽

Mariah Farrell ◽

Heather Fairfield ◽

Lucy Kirkham-McCarthy ◽

Matt Macauley ◽

...

Keyword(s):

Multiple Myeloma ◽

Drug Resistance ◽

Board Of Directors ◽

Research Funding ◽

Immune Cell ◽

Sialyl Lewis X ◽

Advisory Committees ◽

Selectin Ligands

Abstract Introduction Multiple myeloma (MM) is a cancer of clonal plasma cells that hijack the bone marrow (BM) niche to create a drug resistant, incurable malignancy. Aberrant sialylation has been linked to immune cell evasion, drug resistance, and metastasis in cancer; indeed sialyltransferases, including ST3GAL1, ST3GAL4 and ST3GAL6, are aberrantly expressed in many cancers (Glavey et al., 2014). We have previously shown that targeting ST3GAL6 in MM cells inhibits their ability to extravasate and colonize the BM in mouse models (Glavey et al., 2014). Moreover, we also showed that a subpopulation of MM cells expresses functional E-Selectin ligands which, upon expansion, gives rise to a more aggressive disease and resistance to bortezomib in mice (Natoni et al., 2017). Based off these findings, we herein investigated whether inhibiting sialylation in E-selectin-enriched MM cells with 3Fax-Neu5Ac, a small molecule sialyltransferase inhibitor, could alter the ability of these cells to home in the BM and restore bortezomib sensitivity in vivo. We hypothesized that inhibiting homing of MM cells to the BM will improve survival and that co-treatment with bortezomib and 3Fax-Neu5Ac will have a synergistic effect. Methods E-selectin ligands enriched MM1S cells (either positive or negative for GFP/Luciferase) were derived from parental cells by cell sorting using the HECA-452 antibody, which recognize sialofucosylated E-selectin ligands. We then determined the 3Fax-Neu5Ac dose and exposure times needed to decrease sialylation on these MM cells without causing toxicity. HECA-452-enriched MM1S cells were pretreated with 3Fax-Neu5Ac or vehicle for 7 days before being injected into SCID-beige mice and then treated with vehicle or bortezomib (0.3 mg/kg twice a week). Mice were analyzed via bioluminescence imaging (BLI) to monitor tumor progression and weighed twice a week. Mice were euthanized when they began to show paralysis under our IACUC protocol. 3Fax-Neu5Ac pretreated HECA-452 MM1S cells were also tested in vitro for their ability to adhere and roll on VCAM-1, MAdCAM-1 and E-Selectin under shear stress and to respond to bortezomib in co-culture with HS5 cells. Results Treatment of HECA-452 MM1S cells with 3Fax-Neu5Ac, at 300 μM for 7 days significantly reduced sialylation on these cells. Importantly, reducing sialylation with 3Fax-Neu5AC reduced tumor burden and increased survival, although this did not reach significance for survival (Figure 1A). Both vehicle- and 3Fax-Neu5Ac-treated cells significantly responded to bortezomib in the first 5 weeks of the in vivo study (Figure 1B). However, the HECA-452 MM1S cells did not show increased survival when treated with bortezomib suggesting an acquired mechanism of resistance in vivo. Importantly, pretreatment of the HECA-452 MM1S with 3Fax-Neu5Ac could improve survival of these mice preventing bortezomib resistance. In vitro, the HS5 stromal cells protected the HECA-452 MM1S cells from bortezomib and pretreatment with 3Fax-Neu5Ac partially reverted this protection. Moreover, the HECA-452 MM1S cells pretreated with 3Fax-Neu5Ac displayed reduced adhesion on MAdCAM-1 and E-selectin. Conclusions Sialylation plays an instrumental role in bone homing, BM colonization, and drug resistance of MM cells. Pretreatment of HECA-452 MM1S cells with 3Fax-Neu5Ac decreased their sialylation, restored sensitivity to bortezomib in vivo and prolonged survival in mice. This is likely because 3Fax-Neu5Ac pretreatment has multiple effects on MM cells including reducing cell adhesion mediated-drug resistance and adhesion to key molecules involved in BM homing such as MAdCAM-1 and E-selectin. The reduced adhesion on E-selectin is most likely due to the disruption of E-selectin ligands on the surface of MM cells as they require Sialyl Lewis X to function. Notably, we also found that de-sialylation impairs adhesion on MAdCAM-1 (3Fax-Neu5Ac vs DMSO P=0.038) which, together with E-selectin, is another critical BM homing receptor. This data suggests for the first time that sialylation may controls the affinity of integrin α4β7 and its counter-receptor MAdCAM-1. In turn, this would reduce BM homing and increase MM cells in the circulation were they are more prone to the cytotoxic effects of bortezomib. This study supports the importance of targeting sialylation in MM and provides a strong rationale for further clinical translation of this novel approach. Disclosures O'Dwyer: Glycomimetics: Research Funding; Celgene: Research Funding; BMS: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onkimmune: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Predictors of T Cell Expansion and Clinical Responses Following B-Cell Maturation Antigen-Specific Chimeric Antigen Receptor T Cell Therapy (CART-BCMA) for Relapsed/Refractory Multiple Myeloma (MM)

Blood ◽

10.1182/blood-2018-99-119665 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1974-1974 ◽

Cited By ~ 2

Author(s):

Adam D. Cohen ◽

J. Joseph Melenhorst ◽

Alfred L. Garfall ◽

Simon F Lacey ◽

Megan Davis ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Advisory Committees ◽

Car T ◽

Equity Ownership

Abstract Background: Relapsed/refractory (rel/ref) MM is associated with progressive immune dysfunction, including reversal of CD4:CD8 T cell ratio and acquisition of terminally-differentiated T cell phenotypes. BCMA-directed CAR T cells have promising activity in MM, but the factors that predict for robust in vivo expansion and responses are not known. In a phase 1 study of CART-BCMA (autologous T cells expressing a human BCMA-specific CAR with CD3ζ/4-1BB signaling domains) in refractory MM patients (median 7 priors, 96% high-risk cytogenetics), we observed partial response (PR) or better in 12/25 (47%) (Cohen et al, ASH 2017, #505). Recently, we demonstrated in CLL pts receiving CD19-directed CAR T cells that certain T cell phenotypes prior to generation of the CAR T product were associated with improved in vivo expansion and clinical outcomes (Fraietta et al, Nat Med 2018). We thus sought to identify pre-treatment clinical or immunological features associated with CART-BCMA expansion and/or response. Methods: Three cohorts were enrolled: 1) 1-5 x 108 CART cells alone; 2) cyclophosphamide (Cy) 1.5 g/m2 + 1-5 x 107 CART cells; and 3) Cy 1.5 g/m2 + 1-5 x 108 CART cells. Phenotypic analysis of peripheral blood (PB) and bone marrow (BM) mononuclear cells, frozen leukapheresis aliquots, and phenotype and in vitro kinetics of CART-BCMA growth during manufacturing were performed by flow cytometry. CART-BCMA in vivo expansion was assessed by flow cytometry and qPCR. Responses were assessed by IMWG criteria. Results: Responses (≥PR) were seen in 4/9 pts (44%, 1 sCR, 2 VPGR, 1 PR) in cohort 1; 1/5 (20%, 1 PR) in cohort 2; and 7/11 (64%, 1 CR, 3 VGPR, 3 PR) in cohort 3. As of 7/9/18, 3/25 (12%) remain progression-free at 11, 14, and 32 months post-infusions. As previously described, responses were associated with both peak in vivo CART-BCMA expansion (p=0.002) as well as expansion over first month post-infusion (AUC-28, p=0.002). No baseline clinical or MM-related characteristic was significantly associated with expansion or response, including age, isotype, time from diagnosis, # prior therapies, being quad- or penta-refractory, presence of del 17p or TP53 mutation, serum hemoglobin, BM MM cell percentage, MM cell BCMA intensity, or soluble BCMA concentration. Treatment regimen given before leukapheresis or CART-BCMA infusions also had no predictive value. We did find, however, that higher CD4:CD8 T cell ratios within the leukapheresis product were associated with greater in vivo CART-BCMA expansion (Spearman's r=0.56, p=0.005) and clinical response (PR or better; p=0.014, Mann-Whitney). In addition, and similar to our CLL data, we found that a higher frequency of CD8 T cells within the leukapheresis product with an "early-memory" phenotype of CD45RO-CD27+ was also associated with improved expansion (Spearman's r=0.48, p=0.018) and response (p=0.047); Analysis of manufacturing data confirmed that higher CD4:CD8 ratio at culture start was associated with greater expansion (r=0.41, p=0.044) and, to a lesser degree, responses (p=0.074), whereas absolute T cell numbers or CD4:CD8 ratio in final CART-BCMA product was not (p=NS). In vitro expansion during manufacturing did associate with in vivo expansion (r=0.48, p=0.017), but was not directly predictive of response. At the time of CART-BCMA infusion, the frequency of total T cells, CD8+ T cells, NK cells, B cells, and CD3+CD56+ cells within the PB or BM was not associated with subsequent CART-BCMA expansion or clinical response; higher PB and BM CD4:CD8 ratio pre-infusion correlated with expansion (r=0.58, p=0.004 and r=0.64, p=0.003, respectively), but not with response. Conclusions: In this study, we found that CART-BCMA expansion and responses in heavily-pretreated MM patients were not associated with tumor burden or other clinical characteristics, but did correlate with certain immunological features prior to T cell collection and manufacturing, namely preservation of normal CD4:CD8 ratio and increased frequency of CD8 T cells with a CD45RO-CD27+ phenotype. This suggests that patients with less dysregulated immune systems may generate more effective CAR T cell products in MM, and has implications for optimizing patient selection, timing of T cell collection, and manufacturing techniques to try to overcome these limitations in MM patients. Disclosures Cohen: Celgene: Consultancy; Novartis: Research Funding; Oncopeptides: Consultancy; Janssen: Consultancy; Poseida Therapeutics, Inc.: Research Funding; Bristol Meyers Squibb: Consultancy, Research Funding; Kite Pharma: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Seattle Genetics: Consultancy. Melenhorst:Parker Institute for Cancer Immunotherapy: Research Funding; novartis: Patents & Royalties, Research Funding; Casi Pharmaceuticals: Consultancy; Incyte: Research Funding; Shanghai UNICAR Therapy, Inc: Consultancy. Garfall:Amgen: Research Funding; Kite Pharma: Consultancy; Bioinvent: Research Funding; Novartis: Research Funding. Lacey:Novartis Pharmaceuticals Corporation: Patents & Royalties; Parker Foundation: Research Funding; Tmunity: Research Funding; Novartis Pharmaceuticals Corporation: Research Funding. Davis:Novartis Institutes for Biomedical Research, Inc.: Patents & Royalties. Vogl:Karyopharm Therapeutics: Consultancy. Pruteanu:Novartis: Employment. Plesa:Novartis: Research Funding. Young:Novartis: Patents & Royalties, Research Funding. Levine:Novartis: Consultancy, Patents & Royalties, Research Funding; CRC Oncology: Consultancy; Incysus: Consultancy; Tmunity Therapeutics: Equity Ownership, Research Funding; Brammer Bio: Consultancy; Cure Genetics: Consultancy. June:Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding; Immune Design: Membership on an entity's Board of Directors or advisory committees; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Novartis Pharmaceutical Corporation: Patents & Royalties, Research Funding; Immune Design: Membership on an entity's Board of Directors or advisory committees; Celldex: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tmunity Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Stadtmauer:Takeda: Consultancy; Celgene: Consultancy; Amgen: Consultancy; AbbVie, Inc: Research Funding; Janssen: Consultancy. Milone:Novartis: Patents & Royalties.

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Bion-1301: A Novel Fully Blocking APRIL Antibody for the Treatment of Multiple Myeloma

Blood ◽

10.1182/blood.v128.22.2112.2112 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2112-2112 ◽

Cited By ~ 1

Author(s):

John Dulos ◽

Driessen Lilian ◽

Marc Snippert ◽

Marco Guadagnoli ◽

Astrid Bertens ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cell ◽

Board Of Directors ◽

Clinical Development ◽

Advisory Committees ◽

Equity Ownership ◽

Parental Antibody

Abstract A PRoliferation Inducing Ligand (APRIL, TNFSF13), is a ligand for the receptors BCMA and TACI. APRIL serum levels are enhanced in patients diagnosed with Multiple Myeloma (MM), Chronic Lymphocytic Leukemia (CLL), and Colorectal Carcinoma correlated with poor prognosis. Our anti-APRIL antibody blocked CLL survival and inhibited mouse B1 hyperplasia in vivo (Guadagnoli et al., 2011). APRIL is produced by cells in the bone marrow niche, including myeloid-derived cells, osteoclasts and plasmacytoid dendritic cells. APRIL critically triggers BCMA in vitro and in vivoto drive proliferation and survival of human MM cells (Tai et al., 2016). Importantly, APRIL induces resistance to lenalidomide, bortezomib and other standard-of-care drugs. Furthermore, APRIL drives expression of PD-L1, IL-10, VEGF and TGFβ forcing an immunosuppressive phenotype on BCMA+ cells. As MM survival, resistance to treatment and the immunosuppressive phenotype can be blocked by neutralizing APRIL (Tai et al., 2016), development of an antibody blocking APRIL provides a novel avenue for the treatment of MM. A novel mouse anti-human APRIL antibody hAPRIL.01A (Guadagnoli et al., 2011) initially discovered using Aduro's B-Select platform, was humanized and further engineered enhancing its stability (designated as BION-1301). The antibody binds to recombinant human APRIL with a KDof 0.4 ± 0.15 nM determined by BioLayer Interferometry and an EC50 of 0.29 ± 0.05 nM by ELISA. The epitope of BION-1301 was mapped to the BCMA and TACI binding site explaining its fully blocking capacity. Blocking potency (IC50) was 1.61 ± 0.78 nM (BCMA) and 1.29 ± 0.89 nM (TACI) respectively, corroborated by potent and complete blockade of APRIL-induced cytotoxicity of BCMA-Fas and TACI-Fas Jurkat transfectants. In vitro, BION-1301 suppressed APRIL-induced B-cell IgA and IgG class switching in a dose-dependent fashion. In vivo, BION-1301 was shown to suppress human APRIL induced T cell-independent B cell responses to NP-Ficoll. Biophysical and functional experiments indicated that BION-1301 recapitulated all characteristics of the mouse parental antibody hAPRIL.01A. To support the clinical development of BION-1301, quantitative assays were developed using several mouse-anti-human APRIL antibodies and shown to detect free and complexed APRIL in human blood samples. Results obtained with assays demonstrate that APRIL can be quantified reproducibly in human sera and overcome the drawbacks of previous assays, such as requirement of polyclonal sera, Ig adsorption, interference by human serum and reduced sensitivity. In conclusion, we have generated and functionally characterized a novel humanized APRIL neutralizing antibody, designated BION-1301. The mechanism-of-action and anti-tumor activity described for the parental antibody hAPRIL.01A in vitro and in vivo strongly support the development of BION-1301 as a single agent or in combination with lenalidomide, bortezomib, and suggest a rationale for combination with checkpoint inhibitors. BION-1301 is expected to enter clinical development in 2017. References:Guadagnoli M, Kimberley FC, Phan U, Cameron K, Vink PM, Rodermond H, Eldering E, Kater AP, van Eenennaam H, Medema JP. Development and characterization of APRIL antagonistic monoclonal antibodies for treatment of B-cell lymphomas. Blood. 2011 Jun 23;117(25):6856-65Tai YT, Acharya C, An G, Moschetta M, Zhong MY, Feng X, Cea M, Cagnetta A, Wen K, van Eenennaam H, van Elsas A, Qiu L, Richardson P, Munshi N, Anderson KC. APRIL and BCMA promote human multiple myeloma growth and immunosuppression in the bone marrow microenvironment. Blood. 2016 Jun 23;127(25):3225-36 Disclosures Dulos: Aduro Biotech Inc.: Equity Ownership. Lilian:Aduro Biotech Inc.: Equity Ownership. Snippert:Aduro Biotech Inc.: Equity Ownership. Guadagnoli:Aduro Biotech Inc.: Equity Ownership. Bertens:Aduro Biotech Inc.: Equity Ownership. David:Aduro Biotech Inc.: Equity Ownership. Anderson:Gilead: Membership on an entity's Board of Directors or advisory committees; Oncoprep: Equity Ownership; Oncoprep: Equity Ownership; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acetylon: Equity Ownership; Acetylon: Equity Ownership; Millennuim: Membership on an entity's Board of Directors or advisory committees; Millennuim: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Equity Ownership; C4 Therapeutics: Equity Ownership; Bristol Myers Squibb: 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. Eenennaam:Aduro Biotech Inc.: Equity Ownership. Elsas:Aduro Biotech Inc.: Equity Ownership.

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