Targeted Degradation of IRAK4 Protein Via Heterobifunctional Small Molecules for Treatment of MYD88 Mutant Lymphoma

Abstract Recurrent mutations in the scaffolding protein MYD88 are present in 30-40% of activated B cell diffuse lymphocytic B cell lymphoma (ABC-DLBCL)(Ngo et al. Nature 2011). MYD88 links activated interleukin 1 receptor (IL1R) and Toll-like receptors (TLRs) to downstream effectors by nucleating assembly of the Myddosome, a multi-protein complex containing MYD88, the protein kinases IRAK4 and IRAK1 and the pseudokinase IRAK2, via oligomerization of the N-terminal Death Domains in each of these proteins (Motshwene et al. JBC 2009; Lin, Lo and Wu. Nature 2010). The most prevalent MYD88 mutation, L265P, constitutively activates assembly of the Myddosome, causing IRAK4-dependent NFκB and MAP kinase signaling and leading to lymphoma survival and proliferation (Ngo et al. Nature 2011). Constitutive activation of the Myddosome has proven to be difficult to drug. MYD88 and IRAK2 lack enzymatic activity and cannot be targeted by conventional small molecule catalytic inhibitors. There are no IRAK1 inhibitors in clinical trials. Specific inhibitors of the kinase activity of IRAK4 have shown limited activity as single agents in preclinical models of MYD88 mutant lymphoma (Lim et al. Blood 2012; Booher et al. Blood 2014). This is consistent with the observations that there is kinase-independent activity of IRAK4 in mediating downstream signals, such as those leading to induction of NFκB (Qin et al. JBC 2004; Fraczek et al. JBC 2008; Sun et al. Sci Signal. 2016). IRAK4 kinase inhibitors thus might not provide optimal blockade of NFκB-dependent tumor survival signals driven by MYD88 mutations in ABC-DLBCL. Kymera Therapeutics is advancing a new class of drugs based on targeted protein degradation: heterobifunctional molecules that recruit disease-causing proteins to specific E3 ubiquitin ligases, resulting in their ubiquitination and subsequent degradation. We have developed a portfolio of potent and specific degraders of IRAK4 with drug-like properties Our lead molecules cause potent and specific degradation of IRAK4 in the ABC-DLBCL cell lines OCI-LY10 (MYD88 L265P) and U2932 (MYD88 WT) while showing selective cytotoxic effects on OCI-LY10 vs U2932. The apoptotic response is triggered within 24-48 h in OCI-LY10, demonstrated by appearance of cleaved caspase 3 and PARP. Quantitative proteomic studies show selective degradation of IRAK4 vs five to six thousand other proteins detected in OCI-LY10. IRAK4 degraders were tested in an OCI-LY10 xenograft model with daily dosing for 28 days, to determine the level of IRAK4 degradation and impact of that degradation on tumor growth in vivo. We observed that degraders mediated decrease in IRAK4 in vivo and produced a statistically significant decrease in tumor growth rate. Here we will present in vitro and in vivo activity and mechanism of action of our most advanced IRAK4 degraders. These IRAK4 degrader molecules represent a new therapeutic modality and provide an exciting opportunity to treat MYD88 mutation-driven ABC-DLBCL. Disclosures Kelleher: Kymera Therapeutics: Employment, Equity Ownership. Audoly:Kymera Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Campbell:Kymera Therapeutics: Employment, Equity Ownership. Chen:Kymera Therapeutics: Employment, Equity Ownership. Ji:Kymera Therapeutics: Employment, Equity Ownership. Kamadurai:Kymera Therapeutics: Employment, Equity Ownership. Li:Kymera Therapeutics: Employment, Equity Ownership. Loh:Kymera Therapeutics: Employment, Equity Ownership. Rong:Kymera Therapeutics: Employment, Equity Ownership. Vigil:Kymera Therapeutics: Employment, Equity Ownership. Weiss:Kymera Therapeutics: Employment, Equity Ownership. Yuan:Kymera Therapeutics: Employment, Equity Ownership. Zhang:Kymera Therapeutics: Employment, Equity Ownership. Mainolfi:Kymera Therapeutics: Employment, Equity Ownership.

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The Combination of Entospletinib and Vincristine Demonstrates Synergistic Activity in a Broad Panel of Hematological Cancer Cell Lines and Anti-Tumor Efficacy in a DLBCL Xenograft Model

Blood ◽

10.1182/blood.v126.23.5123.5123 ◽

2015 ◽

Vol 126 (23) ◽

pp. 5123-5123 ◽

Cited By ~ 6

Author(s):

Mark Joseph Axelrod ◽

Peter Fowles ◽

Jeff Silverman ◽

Astrid Clarke ◽

Jennifer Tang ◽

...

Keyword(s):

Tumor Growth ◽

Growth Inhibition ◽

B Cell ◽

Cell Lines ◽

Xenograft Model ◽

Lymphocytic Leukemia ◽

Employment Equity ◽

Equity Ownership

Abstract Background Entospletinib (GS-9973) selectively inhibits spleen tyrosine kinase (SYK), a critical signaling component of the BCR pathway that is expressed primarily in cells of hematopoietic lineage including normal and malignant B-lymphocytes. Entospletinib is currently in phase II clinical trials, where it has demonstrated both a high degree of safety as well as efficacy against chronic lymphocytic leukemia (Sharman, J., et al. Blood, 2015) and other B cell malignancies. Despite these successes, new therapeutic options, including combinations with standard of care agents, are needed in order to achieve the goal of curing disease through finite treatment. We show here that the combination of entospletinib and vincristine causes synergistic apoptosis in vitro in a broad panel of cell lines derived from hematological cancers including diffuse large B cell lymphoma (DLBCL), acute lymphocytic leukemia, follicular lymphom), multiple myeloma, and acute myelogenous leukemia. We also evaluated and compared the in vivo efficacy of entospletinib and vincristine as singe agents and in combination in a DLBCL tumor xenograft model using the SU-DHL-10 cell line. Methods In vitro growth inhibition of a panel of malignant hematological cell lines was assessed using CellTiter-Glo™ Assay (Promega) after 72h incubation with entospletinib or vincristine alone or in combination. Synergy was evaluated using the Bliss model of independence (Meletiadis, J., et al., Med Mycol, 2005). In vivo, SU-DHL-10 cells (5 x 106 cells) were implanted subcutaneously in the axilla in male SCID beige mice. All mice were sorted into study groups on Day 16 such that each group's mean tumor volume fell within 10% of the overall mean (197mm3). Dosing was initiated on Day 16 and animals were dosed for 17 days. Plasma concentrations of entospletinib and vincristine were assessed on Day 19, and the entospletinib 75 mg/kg dose was lowered on Day 22 to 50 mg/kg to approximate the human achievable SYK target coverage of EC80. Efficacy and tolerability were evaluated by tumor measurements and body weight monitored three times weekly. Tumor burden data were analyzed by the application of a two-way analysis of variance (ANOVA), with post-hoc analysis. Results In vitro combinations of entospletinib with low concentrations of vincristine resulted in marked inhibition of cell proliferation and induction of apoptosis in a broad panel of 19 tumor cell lines representing major B cell malignancies including DLBCL. The combination of entospletinib with vincristine had a profound inhibitory effect on proliferation in all subtypes of DLBCL. Entospletinib was evaluated at a concentration equivalent to the Cminof the clinical dose and vincristine was used at concentrations (≤ 10 nM) that had little to no significant single agent effect in these cell lines. In vivo in a SU-DHL-10 xenograft model, entospletinib dosed alone at 25 or 75/50 mg/kg significantly inhibited tumor growth, causing 39% and 20% tumor growth inhibition (TGI), respectively, compared to the vehicle-treated control group. Vincristine administered at either 0.15 and 0.5 mg/kg Q7D x 3 also resulted in significant TGI (42% and 85% TGI, respectively). The addition of entospletinib (75/50 mg/kg) to 0.5 mg/kg or 0.15 mg/kg vincristine resulted in a significant increase in TGI from 85% to 96% (p= 0.001) and 42% to 71% (p< 0.0001), respectively. The addition of entospletinib (25 mg/kg) to vincristine did not significantly increase the tumor growth inhibition. While the groups receiving either entospletinib or vincristine as single agents had no complete or partial tumor regression, 50% of the mice receiving the combination of 75/50 mg/kg entospletinib with 0.5 mg/kg vincristine had partial responses, 8% had complete regression and 8% were tumor free at the end of study (Figure 1). Conclusion Entospletinib and vincristine demonstrated efficacy and tolerability both alone and in combination in the SU-DHL-10 DLBCL cell line xenograft model in SCID beige mice. Vincristine combinations with entospletinib showed significantly greater efficacy than vincristine alone. These data support the further clinical development of entospletinib in combination with vincristine for the treatment of DLBCL. a ENTO: PO: Q12H x 2 (Day 16-32) b VCR: IV: Q7D x 3 (Days 18, 25, 32) Figure 1. Tumor Regressions in an Entospletinib/ Vincristine Treated Murine DLBCL Xenograft Figure 1. Tumor Regressions in an Entospletinib/ Vincristine Treated Murine DLBCL Xenograft Disclosures Axelrod: Gilead Sciences: Employment, Equity Ownership. Fowles:Gilead Sciences: Employment, Equity Ownership. Silverman:Gilead Sciences: Employment, Equity Ownership. Clarke:Gilead Sciences: Employment, Equity Ownership. Tang:Gilead Sciences: Employment, Equity Ownership. Rousseau:Gilead Sciences: Employment, Equity Ownership. Webb:Gilead Sciences: Employment, Equity Ownership. Di Paolo:Gilead Sciences: Employment, Equity Ownership.

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Klotho/IGF-1R Regulates Tumor Growth and Predicts Prognosis in Diffuse Large B-Cell Lymphoma

Blood ◽

10.1182/blood.v128.22.2924.2924 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2924-2924

Author(s):

Xiangxiang Zhou ◽

Ying Li ◽

Xinyu Li ◽

Lingyun Geng ◽

Ya Zhang ◽

...

Keyword(s):

Tumor Growth ◽

B Cell ◽

Cell Lines ◽

Xenograft Model ◽

B Cell Lymphoma ◽

Control Group ◽

Klotho Protein ◽

Xenograft Models

Abstract Introduction: Klotho is an anti-aging gene with an extracellular domain. Mice with Klotho knockout exhibited obvious impairment in B-cell development. Evolving evidence indicates that Klotho modulates the proliferation and survival via targeting insulin-like growth factor-1 receptor (IGF-1R) in several cancers. However, the expression and biological role of Klotho in B-cell non-Hodgkin lymphoma (B-NHL) has not been elucidated to date. We hypothesized that Klotho could modulate the tumor growth and predicts prognosis in diffuse large B-cell lymphoma (DLBCL) through inhibiting IGF-1R activation. The aim of this study is to characterize the functional significance of Klotho and the therapeutic potential of its secreted form in DLBCL. Methods: Lymph nodes samples from 50 de novo DLBCL and 20 reactive hyperplasia cases were collected with informed consents. Klotho expression were assessed by Immunohistochemistry. CD19+ B-cells and peripheral blood mononuclear cells were isolated with informed consents from healthy donors. Expression levels of Klotho mRNA and protein in DLBCL cells were determined by quantitative RT-PCR and western blotting. Lentivirus vectors either encoding Klotho (LV-KL) or empty lentiviral vector (LV-Con) were stably transfected into DLBCL cells. Cell viability and apoptosis were analyzed by cell counting kit-8 and Annexin V-PE/7AAD staining. Animal experiments were performed in accordance with the principles of the Institutional Animal Care. SCID-Beige mice were subcutaneously injected with DLBCL cells to establish xenograft model. Results: We observed markedly decreased level of Klotho protein in DLBCL lymph nodes (Fig. 1A). Expression of Klotho protein exhibited significantly negative correlation with Ann Arbor stage of DLBCL patients (p=0.002). Level of Klotho protein was negatively correlates with the media overall survival (OS), suggesting lower Klotho expression is associated with poor OS in DLBCL ((Fig. 1B, p=0.045). Reduction of Klotho was also confirmed in DLBCL cell lines at mRNA and protein level (Fig. 1C). We next functionally interrogated the role of Klotho in DLBCL cell lines and xenograft models. Stably expression of LV-KL in DLBCL cell lines resulted in dramatically decreased cell proliferation and incremental apoptotic rates when compared to LV-Con (Fig. 2A and B). We validated the changed expression of critical targets known to govern apoptosis in DLBCL cells transfected with LV-KL. Xenograft models with Klotho overexpression revealed significantly abrogated tumor growth compared to control group (Fig. 2C). Interestingly, lower levels of Ki67 were observed in mice treated with LV-KL (Fig. 2D). These results highlighted the proliferation-inhibitory and apoptosis-inductive activities of Klotho in DLBCL cells. The underlying mechanism driving the tumor suppressive potential of Klotho was investigated. Surprisingly, we observed that the Klotho-induced inhibition of cell viability was only fewer restored by IGF-1 in DLBCL cells transfected with LV-KL (Fig. 3A). Reductive phosphorylation of IGF-1R and its downstream targets (AKT and ERK1/2) were observed in DLBCL cells with Klotho overexpression (Fig. 3B). In addition, we evaluated the regulation of Klotho on IGF-1R signaling in vivo. Decreased phosphrolation of IGF-1R as well as its downstream targets were observed in mice treated with LV-KL compared to the control group (Fig. 3C). Lastly, we explored the activity of secreted Klotho protein (rhKL). The rhKL was found to be active in vitro and significantly reduced the viabilities of DLBCL cells (Fig. 3D). Moreover, combination with rhKL increased the sensitivity of DLBCL cells to adriamycin. The in vivo activity of rhKL in DLBCL xenograft model was also detected. Significantly decreased tumor volumes were noted in mice treated with rhKL compared with those treated with vehicle control (Fig. 3E). Moreover, reductive expression level of Ki67 was observed in rhKL-treated group (Fig. 3F). Conclusions: Our observations identified for the first time that loss of Klotho expression contributed to the development and poor prognosis via activating IGF-1R in DLBCL. Given the in vivo tumor suppressive activity of secreted Klotho protein, it may serve as a potential strategy for the development of novel therapeutic interventions for DLBCL. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.

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A Novel Class of Bifunctional Immunotherapeutic That Exploits a Universal Antibody Binding Terminus (uABT) to Recruit Endogenous Antibodies to Cell Expressing CD38 Demonstrate In Vivo efficacy in Three Distinct Animal Models

Blood ◽

10.1182/blood-2019-130838 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1820-1820

Author(s):

Anna Bunin ◽

Katy McGrath ◽

Ann Marie Rossi ◽

Matthew Welsch ◽

Christian Vidal ◽

...

Keyword(s):

Multiple Myeloma ◽

Tumor Growth ◽

Nk Cells ◽

Nk Cell ◽

Xenograft Model ◽

Employment Equity ◽

In Vivo Models ◽

Equity Ownership ◽

Daudi Cells

Background: Antibody recruiting molecules (ARM) represent a new modality in immunotherapy of cancer. These are bifunctional molecules composed of two active termini connected by a linker. One of the termini binds to a target molecule on a cancer cell. The other terminus can recruit endogenous IgG antibodies independent of their antigen binding specificity representing a breakthrough improvement to previous approaches (Murelli et al.J Am Chem Soc. 2009). We named this active moiety a universal antibody binding terminus (uABT). As a result of antibody recruitment to the cell surface, the target cell is "opsonized" by antibodies which then bring in the immune effector cells to eliminate the target through various antibody-dependent destruction mechanisms. Multiple myeloma is a neoplasm that arises from terminally differentiated immunoglobulin producing long-lived plasma cells with 32,000 new cases diagnosed each year. Kleo Pharmaceuticals has developed a series of compounds, CD38-ARM which target human CD38 highly expressed by multiple myeloma cells. CD38 -ARM compounds are therapeutically active in three distinct in vivo models without depleting CD38 expressing immune effector cells like existing therapeutic antibodies such as Daratumumab. Methods: CD38-ARM compounds were tested in three independent in vivo models. In the first model, intraperitoneal Daudi xenograft in SCID mice, 20x106 fluorescently labelled Burkitt lymphoma CD38-expressing Daudi cells were injected into SCID mice and treated with 3 mg/kg of compounds. Peritoneal exudates were examined 24 hours later for percentages and absolute numbers of Daudi cells recovered. Activity of compounds was further tested in a MOLP-8 multiple myeloma cell xenograft model in nude mice. Animals received 106 MOLP8 cells subcutaneously, and were treated with a daily dose of 10 mg/kg after tumor volumes of 150 mm3 were reached. Finally, CD38-ARM efficacy was examined in hu IL-15 transgenic NOG mice that have been preconditioned with busulfan and reconstituted i.p. with 2x106human NK cells. Three weeks after reconstitution, 5x106RAJI cells expressing CD38 were implanted s.c. and treatment commenced a week later with 10 mg/kg QDx14. Mice were monitored for NK cell levels and activation status in the blood during the whole study duration by flow cytometry. Results: CD38-uAbt compounds are able to induce clearance of Burkitt's lymphoma Daudi cells expressing high levels of CD38 in a SCID mouse intraperitoneal model. In addition, we show efficacy of one of these compounds in a multiple myeloma xenograft model in nude mice. Using the MOLP8 subcutaneously implanted tumor model we show that administration of our lead molecule is able to induce 50% tumor growth inhibition (TGI) after a daily dosing schedule against this tumor. This activity is comparable to a pharmacologically relevant dose of Daratumumab. Finally, we demonstrate that CD38-ARM treatment shows significant efficacy in humanized mouse model, where IL-15 Tg NOG mice have been reconstituted with human NK cells prior to tumor implantation. In this model daily dosing with the CD38-ARM resulted in up to 70% TGI when compared to untreated control groups. Using this dose/schedule, the molecule did not elicit NK cell depletion as noted in the Daratumumab group. Conclusions: We demonstrated that CD38-ARM compounds are therapeutically active in three distinct in vivo models. Depletion of Daudi cells in a peritoneal SCID model provides strong evidence for the CD38-ARM's capacity to engage macrophage effector functions. Profound inhibition of tumor growth in the NK cell centered humanized hIL-15 Tg NOG mouse model indicates that killing of target cells is executed by human NK cells and provides a foundation to advancing our compounds towards the clinic. Overall, our results demonstrate value of CD38-ARM molecules both as stand-alone therapeutic as well as a platform to develop compounds tailored to a specific indication, by varying target binding moiety of the molecule. Our results also indicate that CD38-ARM compounds engage a variety of effector mechanisms involved in tumor clearance and tumor growth delay, indicating therapeutic potential across a wide range of clinical settings. Disclosures Bunin: Kleo pharmaceuticals: Employment, Equity Ownership. McGrath:Kleo pharmaceuticals: Employment, Equity Ownership. Rossi:Kleo pharmaceuticals: Employment, Equity Ownership. Welsch:Kleo pharmaceuticals: Employment, Equity Ownership. Vidal:Kleo pharmaceuticals: Employment, Equity Ownership. Trinh:Kleo pharmaceuticals: Employment, Equity Ownership. Spiegel:Kleo pharmaceuticals: Equity Ownership. Rastelli:Kleo pharmaceuticals: Employment, Equity Ownership. Alvarez:Kleo pharmaceuticals: Employment, Equity Ownership.

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Lenalidomide Efficacy in Activated B-Cell-Like Subtype Diffuse Large B-Cell Lymphoma Is Dependent Upon IRF4 and Cereblon Expression

Blood ◽

10.1182/blood.v120.21.3287.3287 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3287-3287

Author(s):

Ling-Hua Zhang ◽

Jolanta Kosek ◽

Maria Wang ◽

Carla Heise ◽

Peter H Schafer ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Molecular Mechanisms ◽

Cell Lymphoma ◽

Xenograft Model ◽

B Cell Lymphoma ◽

Cell Receptor ◽

Employment Equity ◽

Large B Cell Lymphoma ◽

Equity Ownership

Abstract Abstract 3287 Background: Durable responses with lenalidomide monotherapy have been reported in patients with non-Hodgkin lymphoma. In relapsed/refractory diffuse large B-cell lymphoma (DLBCL), higher responses were observed in the activated B-cell-like (ABC) subtype than in the germinal centre B-cell (GCB)-like subtype (Czuczman, et al. British Journal of Haematology, 2011, 154, 477–481). Herein, the molecular mechanisms involved in the differential efficacy of lenalidomide in DLBCL subtypes were investigated. Methods: A panel of DLBCL cell lines, with 5 of ABC-subtype and 11 of non-ABC subtype, was collected and cell of origin subtype was confirmed based on literature, molecular and genetic analysis. The direct antiproliferative effect of lenalidomide on DLBCL cells was assessed using the 3H-thymidine incorporation assay and apoptosis analysis. The molecular mechanisms involved in the antiproliferative efficacy of lenalidomide in DLBCL subtypes were investigated by western blot, immunohistochemistry (IHC) and qRT-PCR analysis of key signaling events during B-cell receptor (BCR)-dependent NF-κB activation. The critical roles of interferon regulatory factor 4 (IRF4), and cereblon (CRBN) in lenalidomide efficacy were established by knock-in or knock-down of these proteins in sensitive ABC cells. Finally, a mouse xenograft model was used to confirm the antitumor effect of lenalidomide and the relevance of the molecular mechanism involved. Results: Using DLBCL cell lines, lenalidomide treatment was found to preferentially suppress proliferation of ABC-DLBCL cells in vitro at a concentration range of 0.01–100 μM (the median plasma concentration at Cmax for patients receiving 25 mg lenalidomide is 2.2 μM) and delay tumor growth in a human tumor xenograft model of OCI-Ly10 cells (lenalidomide 3–30 mg/kg, p.o. qdX28), with minimal effect on non-ABC-DLBCL cells. This tumoricidal effect of lenalidomide was associated with downregulation of IRF4, a survival factor in ABC-DLBCL cells. Treatment with lenalidomide for 1–3 days, similar to the inhibitors of PKCb and MALT1 (LY-333,531 and z-VRPR-fmk, respectively), was found to significantly (p<0.05) downregulate IRF4 protein levels in sensitive cell lines such as OCI-Ly10 and U2932. IRF4 inhibition by lenalidomide reduced CARD11-BCL-10-MALT1 complex activity of ABC-DLBCL cells (as measured by BCL-10 cleavage) and resulted in downregulation of B-cell receptor (BCR)-dependent NF-κB activity. An NF-κB-driven luciferase assay revealed that lenalidomide (1 μM) inhibited transcriptional activity of NF-κB up to 56% in the sensitive ABC-DLBCL cell lines OCI-Ly10 (p <0.05) and U2932 (p <0.01) after 2-day drug treatment. Lenalidomide also significantly (p <0.05) inhibited DNA binding by Rel A/p65, p50 and c-rel/p70 in 4 lines of ABC cells. While IRF4-specific siRNA mimicked the effects of lenalidomide reducing NF-κB activation, IRF4 overexpression conferred cell resistance to lenalidomide, indicating the crucial role of IRF4 inhibition in lenalidomide efficacy in ABC DLBCL. Furthermore, knockdown of CRBN in OCI-Ly10 (p <0.05) and U2932 (p <0.01) conferred resistance to lenalidomide as demonstrated by the abrogation of the inhibitory effects of lenalidomide on IRF4 expression, BCL-10 cleavage, NF-κB activity, and proliferation of these cells, whereas the activity of inhibitors to PKC β and IKKα/β (LY-333,531 and CC-415501, respectively) remained unaffected. These data indicate that antitumor effects of lenalidomide on ABC-DLBCL cells require the presence of cereblon. Conclusions: These data may provide a mechanism for the preferential efficacy of lenalidomide in ABC-DLBCL observed in clinical studies. These findings suggest that lenalidomide has direct antitumor activity against DLBCL cells, preferentially ABC-DLBCL cells, by blocking IRF4 expression and the BCR-NF-κB signaling pathway in a cereblon-dependent manner (also see Figure below). Disclosures: Zhang: Celgene Corp: Employment, Equity Ownership. Kosek:Celgene Corp: Employment, Equity Ownership. Wang:Celgene Corporation: Employment, Equity Ownership. Heise:Celgene Corporation: Employment, Equity Ownership. Schafer:Celgene: Employment, Equity Ownership. Chopra:Celgene Corporation: Employment, Equity Ownership.

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Pre-Clinical Development of Adct-402, a Novel Pyrrolobenzodiazepine (PBD)-Based Antibody Drug Conjugate (ADC) Targeting CD19-Expressing B-Cell Malignancies

Blood ◽

10.1182/blood.v126.23.1564.1564 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1564-1564 ◽

Cited By ~ 7

Author(s):

Francesca Zammarchi ◽

David G. Williams ◽

Lauren Adams ◽

Karin Havenith ◽

Simon Chivers ◽

...

Keyword(s):

Single Dose ◽

B Cell ◽

Cell Lines ◽

Xenograft Model ◽

B Cell Malignancies ◽

Employment Equity ◽

Equity Ownership ◽

Anti Tumor Activity

Abstract Human CD19 antigen is a 95 kilodalton type I transmembrane glycoprotein belonging to the immunoglobulin superfamily (Wang, Wei, & Liu, 2012). The role of CD19, both in health and disease, is well studied, and the therapeutic efficacy and safety of CD19 modulation have been well defined over several decades (Scheuermann & Racila, 1995). In normal human tissue, expression of CD19 is limited to the various stages of B-cell development and differentiation (except plasma cells) and its expression is maintained on the majority of B-cell malignancies, including B-cell leukemia and non-Hodgkin lymphomas of B-cell origin. CD19 has rapid internalization kinetics and it is not shed into the circulation (Blanc et al., 2011; Gerber et al., 2009). All these features make CD19 an attractive target for the development of an ADC to treat B-cell malignancies. ADCT-402 is an ADC composed of a humanized antibody directed against human CD19, stochastically conjugated via a valine-alanine cleavable, maleimide linker to a PBD dimer cytotoxin. PBD dimers are highly efficient anticancer drugs that covalently bind in the minor groove of DNA and form cytotoxic DNA interstrand cross-links. The average drug to antibody ratio of ADCT-402 is 2.3 ± 0.3, as shown by hydrophobic interaction chromatography and reverse-phase HPLC. In vitro, ADCT-402 demonstrated potent cytotoxicity in a panel of human-derived cell lines of differing levels of CD19, while its potency was strongly reduced in CD19-negative cell lines. In vivo, ADCT-402 demonstrated dose-dependent anti-tumor activity in a subcutaneously implanted human Burkitt's lymphoma-derived Ramos xenograft model, where a single dose at 0.33 mg/kg induced significantly delayed tumor growth compared to the vehicle-treated mice and at 0.66 mg/kg and 1 mg/kg gave 4/10 and 10/10 tumor-free survivors, respectively. In the same model, ADCT-402 showed remarkably superior anti-tumor activity compared to both maytansinoid- and auristatin-based CD19-targeting ADCs, when they were tested at the same dose and schedule (1 mg/kg, single dose). Moreover, ADCT-402 mediated an impressive increase in survival compared to both vehicle-treated and isotype control ADC-treated mice in the disseminated Ramos xenograft model when tested as a single dose at 0.33 mg/kg or 1 mg/kg. For example, a single dose of ADCT-402 at 1 mg/kg resulted in 10/10 survivors at day 91, while there were 0/10 survivors at day 19 in the group of animals treated with either the vehicle control or with a single dose of the non-binding, control ADC at 1 mg/kg. In rat, a single dose of ADCT-402 at 2 mg/kg was well tolerated with no adverse signs or hematologic effects. Altogether, these data show the potent and specific anti-tumor activity of ADCT-402 against CD19-expressing B-cell malignancies, both in vitro and in vivo, and warrant further development of this ADC into the clinic. Disclosures Zammarchi: ADC Therapeutics: Employment. Williams:Spirogen/Medimmune: Employment. Adams:Spirogen/Medimmune: Employment, Equity Ownership. Havenith:ADC Therapeutics: Employment. Chivers:ADC Therapeutics: Employment. D'Hooge:Spirogen/Medimmune: Employment, Equity Ownership. Howard:ADCT Spirogen/Medimmune: Employment, Equity Ownership, Patents & Royalties. Hartley:ADCT Spirogen/Medimmune: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. van Berkel:ADC Therapeutics: Employment, Equity Ownership, Patents & Royalties.

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Concurrent Targeting of BCL2 and MYC Transcription Leads to Chemo-Sensitization of Dual-Expressing Diffuse Large B-Cell Lymphoma In Vivo

Blood ◽

10.1182/blood.v128.22.4090.4090 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4090-4090

Author(s):

Samantha L. Kendrick ◽

Vijay Gokhale ◽

Laurence Hurley ◽

Lisa Rimsza

Keyword(s):

Tumor Growth ◽

B Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Tumor Burden ◽

Dna Structures ◽

Large B Cell Lymphoma ◽

Xenograft Mice ◽

Equity Ownership

Abstract To date, there are no effective strategies to treat patients with a particularly lethal form of diffuse large B-cell lymphoma (DLBCL) that over-express both B-cell lymphoma gene-2 (BCL2) and cellular-myelocytomatosis (MYC) oncogenes. Here, we provide a novel approach for simultaneously targeting BCL2 and MYC directly through secondary DNA structures. These structures act as molecular switches, turning gene expression on or off, and serve as scaffolds for protein and small molecule interaction. Previously identified compounds IMC-76 and GQC-05, recognize the BCL2 or MYC promoter region DNA structures, respectively, and independently lower mRNA and protein expression of each oncogene.For utility in sensitizing aggressive lymphoid tumors that concurrently dual express BCL2 and MYC, we examined the efficacy ofIMC-76 and GQC-05 in the presence and absence of a standard chemotherapy, cyclophosphamide (CPA)to inhibit tumor growth in a severe combinedimmunodeficient U2932 DLBCLxenograft mouse model. Unlike IMC-76, effects of GQC-05 in a xenograftmouse model are unknown; therefore, our initial in vivo studies involved GQC-05 alone and with IMC-76 in combination with CPA to determine the concentration for MYCdown-regulation and a maximum tolerated dose (MTD). At 2.5 and 5 mg/kg GQC-05 with 50 mg/kg CPA, we observed no effect on mean mouse weight and while the 5 mg/kg GQC-05-CPA combination group exhibited some mouse death, LD50 was not reached. Tumors from mice treated with GQC-05 and CPA were compared to diluent or CPA alone treated mice for MYC mRNA level and found to have significantly less MYC expression. As expected, there was no effect on BCL2 mRNA levels. Next, we carried over the 5 mg/kg GQC-05 to a subsequent in vivo experiment where we also tested a 10 mg/kg GQC-05 dose and included IMC-76 at 10 mg/kg, a previously established efficacious dose, to determine if we would reach an MTD, but still retain the repression of MYC. While the mice were able to tolerate the 5 mg/kg GQC-05 dose when IMC-76 and/or CPA was added to the treatment regimen, the LD50 was reached and surpassed in mice treated with the 10 mg/kg of GQC-05 combinations. However, both concentrations of GQC-05 when co-treated with IMC-76 and CPA resulted in a notable decrease of tumor MYC expression relative to untreated and CPA only treated mice as well as a detectable inhibition of BCL2. We then conducted a follow-up study to evaluate effects on tumor burden using concentrations of GQC-05 below the LD50, 5 mg/kg and 7.5 mg/kg, and also reduced the dose of CPA to 30 mg/kg. The co-treatment of mice with IMC-76 (10 mg/kg) and GQC-05 (7.5 mg/kg) in combination with CPA delayed tumor growth and decreased tumor size by 50%, 46%, and 37% at 9, 12, and 15 days post-first-day drug administration compared to the diluent and 50%, 67%, and 44% smaller tumors relative to CPA only treated mice (Figure 1). Overall, there was a prominent decrease in tumor burden in these mice as determined by area under the curveand the tumors displayed a lower expression of BCL2 and MYC at both the mRNA and protein levels. Interestingly, tumors of mice that received IMC-76 and GQC-05 also showed knock-down of BCL2 and MYC, but no effect on tumor burden unless CPA was present indicating these transcriptional inhibitors act as chemo-sensitizers. None of the various drug regimens resulted in a significant loss of mouse weight and while survival for GQC-05 7.5 mg/kg treated mice was reduced, LD50 was not reached. These are the first studies to demonstrate two differentpromoterDNA secondary structures can be targeted at the same time for direct transcriptional inhibition that leads tochemo-sensitization and slowed tumor growth in mice.Our findings demonstrate the potential utility of a dual-targeted, precision medicine-based strategy to improve the response of DLBCL patients to current chemotherapy and overcome resistant disease. Figure Tumor burden of DLBCL xenograft mice Figure. Tumor burden of DLBCL xenograft mice Disclosures Gokhale: Tetragene: Equity Ownership. Hurley:Tetragene: Consultancy, Equity Ownership. Rimsza:NCI/NIH: Patents & Royalties: L.M. Rimsza is a co-inventor on a provisional patent, owned by the NCI of the NIH, using Nanostring technology for determining cell of origin in DLBCL..

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Highly Differentiated Anti-CD47 Antibody, AO-176, Potently Inhibits Hematologic Malignancies Alone and in Combination

Blood ◽

10.1182/blood-2019-126298 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1844-1844

Author(s):

John Richards ◽

Myriam N Bouchlaka ◽

Robyn J Puro ◽

Ben J Capoccia ◽

Ronald R Hiebsch ◽

...

Keyword(s):

Multiple Myeloma ◽

Combination Therapy ◽

Tumor Growth ◽

Growth Inhibition ◽

Tumor Cells ◽

Tumor Growth Inhibition ◽

Employment Equity ◽

Equity Ownership

AO-176 is a highly differentiated, humanized anti-CD47 IgG2 antibody that is unique among agents in this class of checkpoint inhibitors. AO-176 works by blocking the "don't eat me" signal, the standard mechanism of anti-CD47 antibodies, but also by directly killing tumor cells. Importantly, AO-176 binds preferentially to tumor cells, compared to normal cells, and binds even more potently to tumors in their acidic microenvironment (low pH). Hematological neoplasms are the fourth most frequently diagnosed cancers in both men and women and account for approximately 10% of all cancers. Here we describe AO-176, a highly differentiated anti-CD47 antibody that potently targets hematologic cancers in vitro and in vivo. As a single agent, AO-176 not only promotes phagocytosis (15-45%, EC50 = 0.33-4.1 µg/ml) of hematologic tumor cell lines (acute myeloid leukemia, non-Hodgkin's lymphoma, multiple myeloma, and T cell leukemia) but also directly targets and kills tumor cells (18-46% Annexin V positivity, EC50 = 0.63-10 µg/ml) in a non-ADCC manner. In combination with agents targeting CD20 (rituximab) or CD38 (daratumumab), AO-176 mediates enhanced phagocytosis of lymphoma and multiple myeloma cell lines, respectively. In vivo, AO-176 mediates potent monotherapy tumor growth inhibition of hematologic tumors including Raji B cell lymphoma and RPMI-8226 multiple myeloma xenograft models in a dose-dependent manner. Concomitant with tumor growth inhibition, immune cell infiltrates were observed with elevated numbers of macrophage and dendritic cells, along with increased pro-inflammatory cytokine levels in AO-176 treated animals. When combined with bortezomib, AO-176 was able to elicit complete tumor regression (100% CR in 10/10 animals treated with either 10 or 25 mg/kg AO-176 + 1 mg/kg bortezomib) with no detectable tumor out to 100 days at study termination. Overall survival was also greatly improved following combination therapy compared to animals treated with bortezomib or AO-176 alone. These data show that AO-176 exhibits promising monotherapy and combination therapy activity, both in vitro and in vivo, against hematologic cancers. These findings also add to the previously reported anti-tumor efficacy exhibited by AO-176 in solid tumor xenografts representing ovarian, gastric and breast cancer. With AO-176's highly differentiated MOA and binding characteristics, it may have the potential to improve upon the safety and efficacy profiles relative to other agents in this class. AO-176 is currently being evaluated in a Phase 1 clinical trial (NCT03834948) for the treatment of patients with select solid tumors. Disclosures Richards: Arch Oncology Inc.: Employment, Equity Ownership, Other: Salary. Bouchlaka:Arch Oncology Inc.: Consultancy, Equity Ownership. Puro:Arch Oncology Inc.: Employment, Equity Ownership. Capoccia:Arch Oncology Inc.: Employment, Equity Ownership. Hiebsch:Arch Oncology Inc.: Employment, Equity Ownership. Donio:Arch Oncology Inc.: Employment, Equity Ownership. Wilson:Arch Oncology Inc.: Employment, Equity Ownership. Chakraborty:Arch Oncology Inc.: Employment, Equity Ownership. Sung:Arch Oncology Inc.: Employment, Equity Ownership. Pereira:Arch Oncology Inc.: Employment, Equity Ownership.

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Long-term in vivo microscopy of CAR T cell dynamics during eradication of CNS lymphoma in mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1903854116 ◽

2019 ◽

Vol 116 (48) ◽

pp. 24275-24284 ◽

Cited By ~ 11

Author(s):

Matthias Mulazzani ◽

Simon P. Fräßle ◽

Iven von Mücke-Heim ◽

Sigrid Langer ◽

Xiaolan Zhou ◽

...

Keyword(s):

T Cells ◽

Tumor Growth ◽

B Cell ◽

B Cell Lymphoma ◽

Therapeutic Effects ◽

Term Survival ◽

Car T Cells ◽

Car T

T cells expressing anti-CD19 chimeric antigen receptors (CARs) demonstrate impressive efficacy in the treatment of systemic B cell malignancies, including B cell lymphoma. However, their effect on primary central nervous system lymphoma (PCNSL) is unknown. Additionally, the detailed cellular dynamics of CAR T cells during their antitumor reaction remain unclear, including their intratumoral infiltration depth, mobility, and persistence. Studying these processes in detail requires repeated intravital imaging of precisely defined tumor regions during weeks of tumor growth and regression. Here, we have combined a model of PCNSL with in vivo intracerebral 2-photon microscopy. Thereby, we were able to visualize intracranial PCNSL growth and therapeutic effects of CAR T cells longitudinally in the same animal over several weeks. Intravenous (i.v.) injection resulted in poor tumor infiltration of anti-CD19 CAR T cells and could not sufficiently control tumor growth. After intracerebral injection, however, anti-CD19 CAR T cells invaded deeply into the solid tumor, reduced tumor growth, and induced regression of PCNSL, which was associated with long-term survival. Intracerebral anti-CD19 CAR T cells entered the circulation and infiltrated distant, nondraining lymph nodes more efficiently than mock CAR T cells. After complete regression of tumors, anti-CD19 CAR T cells remained detectable intracranially and intravascularly for up to 159 d. Collectively, these results demonstrate the great potential of anti-CD19 CAR T cells for the treatment of PCNSL.

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P03.20 A murine, myc-driven lymphoma model expressing human CD22 enables testing of targeted therapies and their effects on tumor immune microenvironment

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-itoc7.58 ◽

2020 ◽

Vol 8 (Suppl 2) ◽

pp. A30.1-A30

Author(s):

F Gsottberger ◽

C Brandl ◽

S Petkovic ◽

L Nitschke ◽

A Mackensen ◽

...

Keyword(s):

Tumor Growth ◽

B Cell ◽

Targeted Therapies ◽

Immune Cell ◽

Myeloid Cells ◽

B Cell Lymphoma ◽

Primary Lymphoma ◽

Murine Lymphoma

BackgroundThe tumor microenvironment (TME) is composed of various cell types which closely interact via cell cell contacts and cytokines leading to tumor promotion, immune cell inhibition and drug resistance. TME is increasingly recognized for its role in cancer immunotherapies. In B-cell malignancies, myeloid cells play a central role in supporting tumor growth and immune suppression (Roussel et al., 2017, Cancer Immunol Immunother). Despite the importance of a syngeneic TME, preclinical studies with novel drugs have mainly been performed in models lacking a functional immune system. Therefore, we developed an immune competent murine lymphoma model transgenic to human CD22 to study effects of targeted therapies on TME.Materials and MethodsA chimeric CD22 consisting of human extracellular and murine intracellular CD22 (h/mCD22) was introduced in BL6 mice (BL6h/mCD22). Crossbreeding with BL6λ-myc lead to spontaneous development of murine lymphoma that were serially transplanted. Tumor infiltration and TME was characterized by flow cytometry. Mice were treated with Moxetumomab pasudotox, a CD22 targeted immunotoxin and Doxorubicin.ResultsSpontaneously developed tumors in lymphoid organs from BL6h/mCD22 x λ-myc consist of a monomorphic population of h/mCD22+ murine B cells. Three primary lymphoma subclones were isolated from distinct mice and serially transplanted in syngeneic mice. Stable tumor growth was established after subcutaneous (sc) and intravenous (iv) injection. However, TME of sc tumors was infiltrated by less than 1% immune cells, while myc-driven lymphoma in humans usually show substantial immune infiltration. In contrast to sc tumors, systemically growing lymphoma in murine bone marrow (BM) are infiltrated by 30% myeloid cells and 1% T-cells and in murine spleen by 10% and 30%, respectively. Myeloid cells found in these tumors were shown to suppress T cell proliferation in vitro. To test functionality of the h/mCD22 transgene, lymphoma-bearing mice were treated with Moxetumomab, which reduced BM lymphoma infiltration by 20 to 100-fold and infiltration in spleen by 5 to 20-fold in the three lymphoma models. Effects of treatment on TME were analyzed after treatment with Doxorubicin which is known to activate myeloid cells in vivo. Compared to untreated controls, Doxorubicin increased CD11b+ cells in spleen by 1.5-fold. Among these cells, Ly6G+ granulocytic cells increased most substantially.ConclusionsWe established primary, myc-driven h/mCD22+ B-cell lymphoma which stably engraft in syngeneic mice with a TME mimicking myc-driven lymphoma in men. The model responds well to CD22-targeted therapy and Doxorubicin induces expected immunologic changes. Therefore, our unique model provides a platform to test CD22-targeting treatment strategies in an immune competent background.Disclosure InformationF. Gsottberger: None. C. Brandl: None. S. Petkovic: None. L. Nitschke: None. A. Mackensen: None. F. Müller: None.

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Detection of Diffuse Large B-Cell Lymphoma in Peripheral Blood Using High-Throughput Sequencing Assay.

Blood ◽

10.1182/blood.v120.21.2666.2666 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2666-2666

Author(s):

Yasuhiro Oki ◽

Malek Faham ◽

Victoria Carlton ◽

Sattva S. Neelapu ◽

Anas Younes

Keyword(s):

B Cell ◽

Peripheral Blood ◽

High Throughput Sequencing ◽

B Cell Lymphoma ◽

Lymph Node Biopsy ◽

Employment Equity ◽

Tumor Biopsy ◽

Blood Samples ◽

Large B Cell Lymphoma ◽

Equity Ownership

Abstract Abstract 2666 Background: In patients with diffuse large B-cell lymphoma (DLBCL), circulating lymphoma cells in the bloodstream are rarely detected by conventional morphology or flow cytometry evaluation. We developed a high-throughput sequencing based platform, LymphoSIGHT, to detect evidence of lymphoid malignancies in peripheral blood samples, as this could potentially be used for detection of minimal residual disease after treatment. This sequencing method has a sensitivity to detect one lymphoma cell per million leukocytes in peripheral blood. We herein report the results of our pilot study assessing the ability of this method to detect the lymphoma clone in peripheral blood samples from 5 DLBCL patients at the time of diagnosis. Methods: This study has been approved by IRB and consent has been obtained from patients. Using universal primer sets, we amplified immunoglobulin heavy chain (IgH@) variable, diversity, and joining gene segments from genomic DNA in tumor biopsy and peripheral blood samples (plasma and peripheral blood mononuclear cell (PBMC) compartments) collected at initial diagnosis. Amplified products were sequenced to obtain >1 million reads (>10× sequencing coverage per IgH molecule), and were analyzed using standardized algorithms for clonotype determination. Tumor-specific clonotypes were identified for each patient based on their high-frequency within the B-cell repertoire in the lymph node biopsy sample. The presence of the tumor-specific clonotype was then quantitated in cell-free and PBMC compartments from the diagnostic blood sample. A quantitative and standardized measure of clone level among all leukocytes in the diagnostic sample was determined using internal reference DNA. Results: We detected a high-frequency IgH clonal rearrangement in all 5 lymph node biopsy samples. The lymphoma clonotype that was identified in the tumor biopsy was also detected in the plasma and/or PBMC compartment in all 5 patients at diagnosis. Specifically, the lymphoma clonotype was detected in the plasma compartment in 4 patients, while 3 patients demonstrated the presence of the lymphoma clonotype in the PBMC compartment (Table 1). We hypothesize that the positive lymphoma clone in the plasma is due to rapid proliferation and necrosis of the primary tumor, releasing the degraded component of lymphoma into the blood stream. However, in this small sample size, we did not observe an obvious correlation between the level of detection (PBMC or plasma) and clinical parameters (LDH, stage, size of tumor, tumor Ki67, cell-of-origin). All patients achieved complete response after initial treatment and four are being followed. We plan to analyze blood specimens while they are in remission. Conclusions: IgH clonal rearrangements were detected by sequencing in all tumor biopsy samples. Importantly, all peripheral blood samples showed signs of circulating lymphoma material in either the plasma or PBMC compartment at diagnosis. Analysis of diagnostic and post-therapy samples from additional DLBCL patients is ongoing. These data will determine whether the sequencing assay is a strong indicator for response to therapy and relapse monitoring. Disclosures: Faham: Sequenta, Inc.: Employment, Equity Ownership, Research Funding. Carlton:Sequenta, Inc.: Employment, Equity Ownership, Research Funding.

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