scholarly journals Obinutuzumab (GA101) Is Less Prone to Antagonism of Immune Effector Function By Ibrutinib Than Rituximab in Vitro and in Vivo

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1765-1765 ◽  
Author(s):  
Sylvia Herter ◽  
Idit Sagiv-Barfi ◽  
Cariad Chester ◽  
Mohith Sadaram ◽  
Jonathan Hebb ◽  
...  
Keyword(s):  
B Cell ◽  
Whole Blood ◽  
Dose Range ◽  
Xenograft Model ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Immune Effector ◽  
The Impact

Abstract Introduction: Kohrt et al., Blood, 2014 demonstrated that ibrutinib antagonizes ADCC function of rituximab in vitro in ADCC assays and in vivo in the DHL-4 xenograft model through inhibition of FcgammaR signaling in immune effector cells, possibly mediated by inhibition of ITK. Obinutuzumab (GA101) is a glycoengineered type II CD20 antibody that mediates higher direct cell death induction than rituximab, and by being glycoengineered mediates enhanced induction of ADCC and ADCP. Here we aimed to investigate the impact of ibrutinib on the immune effector function of obinutuzumab as compared to rituximab. Experimental methods: The impact of ibrutinib (dose range 30, 100, 300 ng/ml to cover Cmax and Ctrough in patients) on NK cell mediated ADCC induction by obinutuzumab and rituximab was investigated using SU-DHL4 and Z138 cells as targets in LDH and chromium release assays or measuring CD16 downmodulation and the degranulation marker CD107a. IFNg release as a surrogate for NK cell activation was investigated using DHL-4 target cells or an autologous in vitro system using leukemic cells derived from CLL/NHL patients. Depletion of CD19 positive B-cells was determined in whole blood from healthy volunteers in flow cytometry-based whole blood assay. In vivo the combination of obinutuzumab or rituximab (10 mg/kg once weekly for 3 weeks) with ibrutinib (25mg/kg BID days 14-28) was investigated in the DHL-4 xenograft model. Results: In ADCC assays, ibrutinib (dose range 30, 100, 300 ng/ml) resulted in a reduction of the ADCC potency of obinutuzumab and rituximab. However, at saturating antibody concentrations of 10 ug/ml, ADCC mediated by obinutuzumab was retained while ADCC mediated by rituximab was strongly reduced as measured by chromium release (Figure 1A). Interestingly, in the whole blood B cell depletion assay only little impact of ibrutinib on obinutuzumab-mediated B cell depletion in terms of EC50 and maximal killing was observed at clinically meaningful concentrations of ibrutinib (30, 100, 300 ng/ml), while the activity of rituximab could be completely abolished with 300 ng/ml ibrutinib (Figure 1B). Notably, control experiments using an effector dead version of obinutuzmab that cannot any longer mediate ADCC or ADCP demonstrate that the retained B cell depletion by obinutuzumab in presence of ibrutinib is not due to direct cell death induction, but also due to immune effector cell mediated function (ADCC and ADCP). In the DHL-4 xenograft model where ibrutinib as a single agent has no anti-tumoral efficacy, the combination resulted in a reduced anti-tumoral efficacy of rituximab, whereas efficacy of obinutuzumab was not affected (Figure 1C). Conclusions: Surprisingly, we found that the inhibitory effect of ibrutinib on the immune effector mediated activity of obinutuzumab is not observed when compared to rituximab. Most notably, ADCC at saturating antibody doses, whole blood B cell depletion and in vivo efficacy of obinutuzumab were retained in presence of clinically relevant concentrations of ibrutinib covering Cmax and Ctrough levels, whereas the activity of rituximab was almost completely abolished under these conditions. We hypothesize that the differential behavior of obinutuzumab and rituximab may be related to the enhanced FcgRIII affinity and stronger FcgRIII signaling activation mediated by obinutuzumab as a consequence of glycoengineering that may subsequently overwrite inhibitory effects of ibrutinib. While the clinical relevance of the observed preclinical antagonism for the combination of rituximab with ibrutinib still needs further clinical investigation, these preclinical data strongly support the clinical investigation of ibrutinib in combination with the glycoengineered Type II CD20 antibody obinutuzumab for the treatment of chronic lymphocytic leukemia and other B-cell malignancies. Figure 1 Figure 1. Disclosures Herter: Roche: Employment. Bacac:Roche: Employment. Umana:Roche: Employment. Klein:Roche: Employment, Equity Ownership, Patents & Royalties.

Combination of the Glycoengineered Type II CD20 Antibody Obinutuzumab (GA101) and the MDM2 Selective Antagonist RG7388 Results in Superior Anti-Tumor Activity

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1780-1780
Author(s):  
Frank Herting ◽  
Sylvia Herter ◽  
Thomas Friess ◽  
Christian Lehmann ◽  
Marina Bacac ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Cell Death ◽  
B Cell ◽  
Whole Blood ◽  
Xenograft Model ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Direct Cell ◽  
B Lymphoid

Abstract Introduction: Obinutuzumab (GA101) is a novel glycoengineered type II, anti-CD20 monoclonal antibody that strongly induces direct cell death. As a result of glycoengineering, obinutuzumab has increased affinity for FcgRIII on innate immune effector cells resulting in enhanced induction of ADCC and ADCP. Obinutuzumab has been approved for first line treatment of CLL patients in combination with chlorambucil in the US and Europe and is currently in pivotal clinical trials in indolent NHL and DLCBL. RG7112, a Nutlin imidazoline-based compound, and RG7388, a pyrrolidine-based compound are novel, orally bioavailable, selective MDM2 antagonists which reactivate p53 and thereby mediate cell cycle arrest and subsequent apoptotic cell death in solid and hematologic tumors. RG7388 is currently in clinical trials for the treatment of AML and prostate cancer. Based on the fact that the majority of B lymphoid malignancies including NHL and CLL bear wildtype p53, and the complementary mechanisms of action involving increased apoptosis (MDM2 antagonist) or direct cell death (obinutuzumab), the combination of both compounds has the potential for superior efficacy in treating B lymphoid malignancies. Experimental methods: The combination of obinutuzumab and RG7388 (or obinutuzumab and rituximab with RG7112, the frontrunner compound with identical mode of action) was studied in vitro utilizing assays that measure direct cell death induction/apoptosis (Annexin V/PI positivity) on p53 wildtype Z138 Mantle cell lymphoma (MCL) and DoHH-2 Diffuse large B-Cell lymphoma (DLBCL) cells by FACS and the impact of MDM2 inhibition on ADCC induction and whole blood B cell depletion. In vivo efficacy of the combination of obinutuzumab or rituximab with RG7122 and RG7388 was evaluated in the s.c. Z138 MCL xenograft model in immunodeficient SCID beige mice. Results: RG7338 induced concentration-dependent cell death of Z-138 and DOHH-2 cell lines. At concentrations > 10-100 nM RG7388 resulted in enhanced cell death induction of DOHH-2 and Z-138 cells in combination with obinutuzumab. Notably, RG7388 did not influence obinutuzumab mediated ADCC during 4 h up to concentrations of 1000 nM and did not affect obinutuzumab mediated NK cell activation (CD16 downregulation, CD107a upregulation). Similarly, addition of RG7388 did not interfere with obinutuzumab mediated B cell depletion in healthy human whole blood at concentrations up to 1000 nM. In the Z-138 xenograft model, the combination of suboptimal doses of 0.5 mg/kg obinutuzumab or 1 mg/kg rituximab with 150 mg/kg RG7112 (three times a week p.o. for 3 weeks) resulted in superior tumor growth inhibition by obinutuzumab as compared to rituximab including the induction of complete tumor remission. In a second Z-138 study, the combination of the suboptimal dose of 0.5 mg/kg obinutuzumab with 80 mg/kg RG7388 yielded similar anti-tumor activity. In summary, the combination of either obinutuzumab or rituximab with RG7112 or the combination of obinutuzumab with RG7388 showed superior in vivo efficacy with no clinical signs of toxicity. Conclusions: The combination of obinutuzumab with MDM2 antagonists results in enhanced cell death of p53 wildtype NHL tumor cells while not affecting obinutuzumab mediated ADCC of tumor cells or B cell depletion in whole blood from healthy donors. In vivo the combination of obinutuzumab with MDM2 inhibitors RG7112 and RG7388 results in robust combined anti-tumor efficacy in xenograft models. Taken together, these preclinical data strongly support the investigation of obinutuzumab and RG7388 combination therapy in clinical trials. Disclosures Herting: Roche: Employment, Patents & Royalties. Herter:Roche: Employment. Friess:Roche: Employment, Patents & Royalties. Lehmann:Roche: Employment. Bacac:Roche: Employment. Dangl:Roche: Employment, Patents & Royalties. Klein:Roche: Employment, Equity Ownership, Patents & Royalties.

The PI3K Delta Selective Inhibitor Idelalisib Minimally Interferes with Immune Effector Function and B Cell Depletion Mediated By Obinutuzumab (GA101) and Rituximab

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3342-3342 ◽  
Author(s):  
Sylvia Herter ◽  
Adam Palazzo ◽  
Marina Bacac ◽  
Laura Grosmaire ◽  
Christian Frey ◽  
...  
Keyword(s):  
B Cell ◽  
Whole Blood ◽  
Nk Cell ◽  
Effector Function ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Immune Effector ◽  
Effector Cells ◽  
Immune Effector Function ◽  
The Impact

Abstract Introduction: Idelalisib is a highly selective oral inhibitor of the phosphoinositide 3-kinase delta (PI3Kδ) that is hyperactive in many B-cell malignancies and is critical for the activation, proliferation, survival and trafficking of B lymphocytes. Idelalisib is approved in the US for the treatment of chronic lymphocytic leukemia (CLL) in combination with rituximab and as monotherapy for patients with relapsed follicular B-cell non-Hodgkin lymphoma and small lymphocytic lymphoma who have received at least two prior systemic therapies. Obinutuzumab (GA101) is a glycoengineered type II, CD20 antibody that induces a high level of direct cell death. As a result of glycoengineering, obinutuzumab has increased affinity for FcγRIII on innate immune effector cells resulting in enhanced induction of ADCC and ADCP. Obinutuzumab has been approved for first line treatment of CLL patients in combination with chlorambucil in the US and Europe and is currently in pivotal clinical trials in indolent NHL and DLBCL. Previous work has shown the covalent BTK inhibitor ibrutinib can interfere with the immune effector function and ultimately in vivo efficacy of rituximab in preclinical models (Kohrt et al., Blood, 2014). As PI3K isoforms also play a role in immune effector cells and FcγR signaling we investigated the impact of PI3Kδ inhibition by the PI3Kδ selective inhibitor idelalisib on the immune effector function of obinutuzumab and rituximab. Experimental methods: The impact of idelalisib on NK cell mediated ADCC induction by obinutuzumab and rituximab was investigated in LDH release assays using WIL2-S, SU-DHL4 and Z138 target cells at plasma protein-binding adjusted clinically relevant concentrations mimicking exposure in patients. As a surrogate for NK cell activation CD16 levels and up-regulation of the degranulation marker CD107a were assessed by FACS. The impact on monocyte-derived macrophage mediated ADCP of WIL2-S cells was measured in a flow cytometry-based phagocytosis assay. Finally, depletion of CD19 positive B cells was determined in whole blood from healthy volunteers in flow cytometry-based whole blood assay. Results: In ADCC assays, no impact of idelalisib on ADCC at saturating concentration of obinutuzumab or rituximab (>1ug/ml) can be detected in LDH release assays with tumor cells targets (N=9 donors for WIL2-S, N>3 donors for SU-DHL-4 and Z138). Idelalisib did not alter obinutuzumab or rituximab ability to kill tumor cells by ADCC at low E:T ratio. Little to no increase of obinutuzumab or rituximab EC50 for LDH release, CD16 down regulation, or degranulation of NK cells could be detected depending on donor effector cells. ADCP assays were conducted with M2c polarized macrophages using WIL2-S as targets. Less than 30% inhibition of ADCP was observed in this assay at idelalisib concentration at protein binding-adjusted clinical Cmax. At idelalisib Cmax (4200 nM) the EC50 of obinutuzumab-mediated B cell depletion in healthy human whole blood was increased 3 to 5 times, whereas at Cmin (760 nM) idelalisib did not significantly influence obinutuzumab EC50 or maximal B cell depletion. Conclusions: PI3Kδ inhibition by idelalisib has minimal impact on the immune effector function of obinutuzumab (GA101) and rituximab as measured in NK cell-mediated ADCC, macrophage-mediated ADCP and whole blood B-cell depletion. Disclosures Herter: Roche: Employment. Palazzo:Gilead Sciences: Employment. Bacac:Roche: Employment. Grosmaire:Gilead Sciences: Employment. Frey:Gilead Sciences: Employment. Pflanz:Gilead Sciences: Employment. Liu:Gilead Sciences: Employment. Tannheimer:Gilead Sciences: Employment. Umana:Roche: Employment. Klein:Roche: Employment, Equity Ownership, Patents & Royalties. Queva:Gilead Sciences: Employment.

Potent B-Cell Depletion by IMGN529, a CD37-Targeting Antibody-Maytansinoid Conjugate for the Treatment of B-Cell Malignancies,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3726-3726
Author(s):  
Jutta Deckert ◽  
Sharon Chicklas ◽  
Yong Yi ◽  
Min Li ◽  
Jan Pinkas ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Whole Blood ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
B Cell Malignancies

Abstract Abstract 3726 CD37 is a B-cell surface antigen which is widely expressed on malignant B cells in non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). In normal tissues CD37 expression is limited to blood cells and lymphoid tissues. This restricted expression profile makes CD37 an attractive therapeutic target for antibodies and antibody-drug conjugates. We developed a novel anti-CD37 antibody, K7153A, which provides a unique combination of functional properties: it demonstrated strong pro-apoptotic and direct cell killing activity against NHL cell lines and could mediate effector activity such as CDC and ADCC. The antibody-maytansinoid conjugate, IMGN529, was produced by conjugation of K7153A with the potent maytansinoid, DM1, via the non-cleavable linker, SMCC. The direct cytotoxic potency of the K7153A antibody was superior to that of the CD20-directed rituximab and was further enhanced with maytansinoid conjugation in IMGN529. In vivo, IMGN529 demonstrated better anti-tumor activity than the K7153A antibody in established subcutaneous follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and CLL xenograft models in SCID mice. A single administration of IMGN529 showed similar or improved efficacy compared to anti-CD20 antibodies or standard chemotherapy where tested. Immunohistochemical (IHC) staining of formalin fixed paraffin-embedded (FFPE) NHL tissue sections was performed to evaluate CD37 expression. CD37 exhibited a similar prevalence to CD20 in subtypes of NHL such as FL, DLBCL, Burkitt's lymphoma (BL) and mantle cell lymphoma (MCL). B-cell depletion is an important measure of efficacy for targeted therapies, such as CD20-directed antibodies, in B-cell malignancies. CD37 expression in blood cells from healthy human donors was measured by quantitative flow cytometry in comparison to CD20. The greatest CD37 expression was found in B cells at approximately 77,000 antibodies bound per cell (ABC), which was similar to CD20 expression in B cells at 95,000 ABC. In other blood cell types CD37 staining was seen at low levels, about 2,000 – 5,000 ABC, in monocytes, NK cells and T cells. In vitro depletion experiments were performed with purified peripheral blood mononuclear cells (PBMCs) and with whole blood, both derived from several healthy donors. Cells were incubated for 1 hr with 10 μg/mL of either K7153A, IMGN529, CD37-targeting TRU-016, rituximab or the anti-CD52 antibody alemtuzumab, with cell depletion determined relative to counting beads by flow cytometry. The K7153A antibody and the IMGN529 conjugate efficiently and specifically depleted B-cells in a dose-dependent manner in the context of purified PBMCs and whole blood. With purified PBMCs, both K7153A and IMGN529 caused 50–60% depletion of B cells, with little to no depletion of T cells or monocytes. IMGN529 was more potent than rituximab, which led to 30–40% B-cell depletion, or TRU-016, which caused 20–30% B-cell depletion. IMGN529 also was more specific than alemtuzumab, which depleted T-cells and monocytes as well as B cells. With whole blood samples, both K7153A and IMGN529 resulted in 30–40% B-cell depletion with no effect on T cells, NK cells or monocytes. IMGN529 was again more potent than rituximab or TRU-016, which caused approximately 10% B-cell depletion, and was more specific than alemtuzumab, which depleted the majority of T cells in addition to 40% of B cells. IMGN529 embodies a unique B-cell targeted agent as it combines the intrinsic pro-apoptotic, CDC and ADCC activities of its anti-CD37 antibody component with the potent cytotoxic mechanism provided by the targeted delivery of its maytansinoid payload. It is highly active in vitro and in vivo against B-cell lymphoma and CLL cell lines. In addition, it mediates specific B-cell depletion in vitro that is greater than B-cell depletion by CD20-directed rituximab. Together, these findings indicate that IMGN529 is a promising therapeutic candidate for the treatment of B-cell malignancies. Disclosures: Deckert: ImmunoGen, Inc.: Employment. Chicklas:ImmunoGen, Inc.: Employment. Yi:ImmunoGen, Inc.: Employment. Li:ImmunoGen, Inc.: Employment. Pinkas:ImmunoGen, Inc.: Employment. Chittenden:ImmunoGen, Inc.: Employment. Lutz:ImmunoGen, Inc.: Employment. Park:ImmunoGen, Inc.: Employment.

scholarly journals In Vivo Delivery of a CD20 CAR Using a CD8-Targeted Fusosome in Southern Pig-Tail Macaques (M. nemestrina) Results in B Cell Depletion

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2769-2769
Author(s):  
Justine Cunningham ◽  
Sundeep Chandra ◽  
Akinola Emmanuel ◽  
Allyse Mazzarelli ◽  
Carmela Passaro ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Systemic Administration ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Car T ◽  
Integrating Vector

Abstract Introduction: Ex vivo manufactured chimeric antigen receptor (CAR) T cell therapies are highly effective for treating B cell malignancies. However, the complexity, cost and time required to manufacture CAR T cells limits access. To overcome conventional ex vivo CAR T limitations, a novel gene therapy platform has been developed that can deliver CAR transgenes directly to T cells through systemic administration of a fusosome, an engineered, target-directed novel paramyxovirus-based integrating vector that binds specific cell surface receptors for gene delivery through membrane fusion. Here, we demonstrate that systemic administration of a CD8a-targeted, integrating vector envelope (i.e., fusogen) encoding an anti-CD20 CAR into Southern pig-tail macaques (M. nemestrina), which is a species permissive to the integrating vector-mediated transduction, results in T cell transduction and B cell depletion with no treatment-related toxicities. Methods: CD8a-specific single chain variable fragments (scFvs) were generated and measured for target specificity versus non-CD8-expressing cells in vitro. Cross-reactivity of the CD8a-specific fusogen for human and nemestrina T cells was confirmed in vitro. Targeted fusogens were then used to pseudotype integrating vector expressing an anti-CD20 CAR containing the 4-1BB and CD3zeta signaling domains (CD8a-anti-CD20CAR). Transduction and B cell killing was confirmed on human and nemestrina PBMCs. To evaluate in vivo activity, normal, healthy nemestrina macaques were treated with a single dose of CD8a-targeted anti-CD20 CAR fusosome (n=6) or saline (n=2) via intravenous infusion at 10mL/kg/hr for 1-hour and evaluated for up to 52 days for evidence of adverse effects, B cell depletion, CAR-mediated cytokine production, CAR T cell persistence and vector biodistribution using ddPCR and anti-CD20CAR transgene by RT-ddPCR to detect transgene levels. Histopathology of several organs and immunohistochemistry for CD3 and CD20 on lymph nodes, spleen, and bone marrow were performed at termination (days 35 and 52). Tolerability of the treatment was assessed by body weight, body temperature, neurological exams, serum chemistry panel, and complete blood counts pre-dose and post-dose up to 52 days. Results: The CD8a-targeted fusogen demonstrated CD8a-specificity versus human CD8 negative cell lines, and cross-reactivity and transduction efficiency in nemestrina PBMCs in vitro. Compared to a control vector (GFP), anti-CD20CAR-modified T cells showed a dose-dependent depletion of B cells using in vitro assays. Following infusion of CD8a-anti-CD20CAR fusosomes into macaques, pharmacological activity in peripheral blood was detected by a reduction of B cells in 4 of 6 animals after 7 to 10 days. Two animals showed persistent B cell depletion until study termination, with two others showing a temporary response. The presence of vector copy could be detected in the peripheral blood of all treated animals between days 3 and 10, and in isolated spleen cells in 5 of 6 animals. All control animals (saline) were negative for vector. RT-ddPCR mRNA expression similarly revealed the presence of anti-CD20CAR transcripts in isolated spleen cells from treated animals; no expression was detected in tissues from control animals. Elevations in inflammatory cytokines could be detected in the serum of treated animals between days 3 and 14. Fusosome treatment was well-tolerated in all animals with no evidence of adverse effects. Moreover, T cell transduction and B cell depletion was not associated with cytokine-related toxicities, and blood chemistry and histopathology were within normal limits. Conclusion: These data obtained in an immunologically competent animal demonstrate the proof-of-concept that systemic administration of a CD8a-anti-CD20CAR fusosome can specifically transduce T cells in vivo without pre-conditioning or T cell activation, resulting in B cell depletion in the absence of vector- or CAR T-related toxicities. Therefore, fusosome technology represents a novel therapeutic opportunity to treat patients with B cell malignancies and potentially overcome some of the treatment barriers that exist with conventional CAR T therapies. Disclosures Cunningham: Sana Biotechnology: Current Employment. Chandra: Sana Biotechnology: Current Employment. Emmanuel: Sana Biotechnology: Current Employment. Mazzarelli: Sana Biotechnology: Current Employment. Passaro: Sana Biotechnology: Current Employment. Baldwin: Sana Biotechnology: Current Employment. Nguyen-McCarty: Sana Biotechnology: Current Employment. Rocca: Sana Biotechnology: Current Employment. Joyce: Sana Biotechnology: Current Employment. Kim: Sana Biotechnology: Current Employment. Vagin: Sana Biotechnology: Current Employment. Kaczmarek: Sana Biotechnology: Current Employment. Chavan: Sana Biotechnology: Current Employment. Jewell: Sana Biotechnology: Current Employment. Lipsitz: Sana Biotechnology: Current Employment. Shamashkin: Sana Biotechnology: Current Employment. Hlavaty: Sana Biotechnology: Current Employment. Rodriguez: Sana Biotechnology: Current Employment. Co: Sana Biotechnology: Current Employment. Cruite: Sana Biotechnology: Current Employment. Ennajdaoui: Sana Biotechnology: Current Employment. Duback: Sana Biotechnology: Current Employment. Elman: Sana Biotechnology: Current Employment. Amatya: Sana Biotechnology: Current Employment. Harding: Sana Biotechnology: Current Employment. Lyubinetsky: Sana Biotechnology: Current Employment. Patel: Sana Biotechnology: Current Employment. Pepper: Sana Biotechnology: Current Employment. Ruzo: Sana Biotechnology: Current Employment. Iovino: Sana Biotechnology: Current Employment. Varghese: Sana Biotechnology: Current Employment. Foster: Sana Biotechnology: Current Employment. Gorovits: Sana Biotechnology: Current Employment. Elpek: Sana Biotechnology: Current Employment. Laska: Sana Biotechnology: Current Employment. McGill: Sana Biotechnology: Current Employment. Shah: Sana Biotechnology: Current Employment. Fry: Sana Biotechnology: Current Employment, Current equity holder in publicly-traded company. Dambach: Sana Biotechnology: Current Employment.

scholarly journals Rituximab Treatment in Hepatitis C Infection: An In Vitro Model to Study the Impact of B Cell Depletion on Virus Infectivity

PLoS ONE ◽  
2011 ◽  
Vol 6 (9) ◽  
pp. e25789 ◽  
Author(s):  
Zania Stamataki ◽  
Samantha Tilakaratne ◽  
David H. Adams ◽  
Jane A. McKeating
Keyword(s):  
Hepatitis C ◽  
B Cell ◽  
In Vitro Model ◽  
Cell Depletion ◽  
Virus Infectivity ◽  
B Cell Depletion ◽  
Hepatitis C Infection ◽  
Vitro Model ◽  
The Impact

Effect of Prior Rituximab on Residence Time of I131 Tositumomab Consolidation Therapy in Patients (pts) with Non Hodgkin’s Lymphoma (NHL): Analysis of SWOG Clinical Trials.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2000-2000
Author(s):  
Julia Schaefer-Cutillo ◽  
Vaseem Chengazi ◽  
Derick R Peterson ◽  
David G. Maloney ◽  
Kevin Kibler ◽  
...  
Keyword(s):  
B Cell ◽  
Residence Time ◽  
Wilcoxon Test ◽  
Cell Depletion ◽  
Residence Times ◽  
B Cell Depletion ◽  
Consolidation Therapy ◽  
Iodine 131 ◽  
The Impact

Abstract Backround: Anti CD-20 radioimmunotherapy (RIT) is effective therapy for indolent B-cell NHL, and under investigation in more aggressive histologies. Most data on safety and efficacy of RIT is from the pre-rituximab era, and the effect of rituximab exposure on RIT in pts with NHL is unknown. Gopal et al recently demonstrated that exposure to rituximab correlated with inferior tumor response and alteration in tumor: organ dosimetry ratio both in vitro and in mouse models following therapy with iodine-131 tositumomab (Blood 112:830). Two ongoing SWOG trials evaluating RIT consolidation therapy provide a unique opportunity to evaluate the impact of prior rituximab on pharmacodynamics of iodine-131 tositumomab in humans. S0016 enrolls previously untreated pts with follicular NHL, and iodine-131 tositumomab consolidation is administered after 6 cycles of CHOP. S0433 enrolls previously untreated pts with DLBCL, and iodine-131 tositumomab is administered after 6 cycles of CHOP with rituximab, and 2 additional cycles of CHOP alone. As rituximab leads to B-cell depletion for 6 months or more, we hypothesized the residence time of iodine-131 tositumomab would differ in pts exposed recently to rituximab compared to no prior rituximab. Methods: Prospective pts at the University of Rochester enrolled in S0016 and S0433 were analyzed. Residence times of iodine-131 tositumomab were calculated using serial imaging on a Picker XP 2000 gamma camera. Rituximab levels were performed within one week prior to dosimetric iodine-131 tositumomab administration using ELISA. Medians were used to summarize the data, and the 2-tailed Mann-Whitney-Wilcoxon test was used for hypothesis testing. Results: 16 pts (6 female) on S0016 and 12 pts (6 female) on S0433, were identified, with median ages of 54.5 and 69.5 respectively. All pts had advanced stage disease, and median BMI and creatinine were similar for both groups. Pts on S0433 had a median time from rituximab to RIT of 78.6 days (range 58–98 days). Despite this, rituximab levels were present at time of iodine-131 tositumomab in all pts measured (N=9; median rituximab level 37.2 ug/ml, range 15.6–61.69). Median absolute lymphocyte count appeared lower in the S0433 group compared to the S0016 group (600 vs 1050 /ul), but this difference was not significant (p=0.12). Pts on S0433 (all had received rituximab prior to iodine-131 tositumomab consolidation) had significantly longer RIT residence times when compared to those on S0016, (not treated with prior rituximab): 115 hours vs. 107 hours; p=0.02. Therapeutic doses of iodine-131 tositumomab were not significantly different between the two studies (S0433: 72 mCi vs. S00016: 78 mCi p=0.59). Conclusions: Our results indicate that prior therapy with rituximab results in a longer residence time of iodine-131 tositumomab when used as consolidation after chemotherapy. Measurable rituximab levels at time of RIT suggest that rituximab-induced B-cell depletion decreases clearance of RIT, possibly allowing for longer exposure times. The significance of this longer residence time is unknown but it could be associated with greater toxicity to normal organs, and could be indicative of decreased tumor binding. If confirmed in larger studies, these findings could have profound implications on RIT administration in the context of rituximab. Rituximab-induced B-cell depletion could obligate the need for unlabeled antibody dosing prior to RIT, and may affect dosimetry of RIT. Prospective studies of RIT in the rituximab era should evaluate the impact of prior rituximab and RIT residence time on toxicities and outcomes in pts treated with RIT.

scholarly journals Duobody-CD3xCD20 Shows Unique and Potent Preclinical Anti-Tumor Activity in Vitro and In Vivo, and Is Being Evaluated Clinically in Patients with B-Cell Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1664-1664 ◽  
Author(s):  
Ida H. Hiemstra ◽  
Patrick J. Engelberts ◽  
Bart de Jong ◽  
Danita H Schuurhuis ◽  
Theodora W. Salcedo ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Cytotoxic Activity ◽  
Subcutaneous Administration ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
B Cell Malignancies ◽  
Equity Ownership

Abstract DuoBody®-CD3xCD20 (GEN3013) is a bispecific antibody (bsAb), recognizing the T-cell antigen CD3 and the B-cell antigen CD20, that triggers potent T-cell-mediated lysis of CD20-expressing cells. DuoBody-CD3xCD20 is a full-length bispecific IgG1 generated by controlled Fab-arm exchange (cFAE) [1, 2] and contains an effector function-silenced Fc region. In vitro, DuoBody-CD3xCD20 induced potent activation, proliferation and cytotoxic activity of both CD4+ and CD8+ T cells in the presence of CD20-expressing cells, as measured by flow cytometry and bromodeoxyuridine (BrdU) incorporation assays. DuoBody-CD3xCD20 induced T-cell-mediated cytotoxicity towards a diverse panel of cell lines derived from various B-cell malignancies and endogenous B cells, with EC50 values in the low picomolar range (EC50: 0.2-5.0 pM). The CD20-specific antibody 7D8 [3-5] forms the basis for the CD20-specific Fab arm of DuoBody-CD3xCD20. To study the contribution of this specific Fab arm to the observed potency of DuoBody-CD3xCD20, we compared the target binding characteristics and the capacity to induce T-cell-mediated cytotoxicity of a CD3 bsAb based on 7D8, with CD3 bsAbs using B-cell targeting arms derived from alternative CD20 antibodies or from antibodies against other well-known B-cell membrane molecules CD22, CD24, CD37, CD70, CD79b, CD138 and HLA-DR. In addition, target expression levels of the B-cell targets were assessed in a panel of B-cell lines. Using a classic chromium release assay, the 7D8-based CD3 bsAb displayed cytotoxic activity superior to all other B-cell-targeting CD3 bsAbs tested, including alternative CD20-targeting CD3 bsAbs. This unique cytotoxic activity could not be explained by expression levels of the target antigen, nor by the binding affinity or epitope of the B-cell specific Fab arm. This illustrates the complexity of factors that determine the potency of CD3 bsAbs. The anti-tumor activity of DuoBody-CD3xCD20 was confirmed in vivo in humanized mouse models using three different B-cell lymphoma xenograft models, in prophylactic and therapeutic settings. Non-clinical safety studies with DuoBody-CD3xCD20 in cynomolgus monkeys demonstrated profound and long-lasting B-cell depletion (at least 70 days, at dose levels > 0.1 mg/kg) from both peripheral blood and lymphoid organs. B-cell depletion was reversible, with time to B-cell recovery correlating with the treatment dose. Notably, at the same dose level, B-cell depletion was comparable between subcutaneous and intravenous administration. Pharmacokinetic (PK) analysis demonstrated comparable bioavailability for the two administration routes, although peak plasma levels were lower and delayed after subcutaneous administration. Moreover, lower plasma cytokine levels were observed after subcutaneous administration. Based on these data, Genmab has initiated a First-in-Human clinical trial to evaluate the safety and preliminary efficacy of DuoBody-CD3xCD20 by subcutaneous administration in patients with B-cell malignancies. The study is currently enrolling (EudraCT No: 2017-001748-36). References Labrijn, A.F., et al., Efficient generation of stable bispecific IgG1 by controlled Fab-arm exchange. Proc Natl Acad Sci U S A, 2013. 110(13): p. 5145-50. Labrijn, A.F., et al., Controlled Fab-arm exchange for the generation of stable bispecific IgG1. Nat Protoc, 2014. 9(10): p. 2450-63. Teeling, J.L., et al., Characterization of new human CD20 monoclonal antibodies with potent cytolytic activity against non-Hodgkin lymphomas. Blood, 2004. 104(6): p. 1793-800. Teeling, J.L., et al., The Biological Activity of Human CD20 Monoclonal Antibodies Is Linked to Unique Epitopes on CD20. Journal of Immunology, 2006. 177(1): p. 362-71. van Meerten, T., et al., HuMab-7D8, a monoclonal antibody directed against the membrane-proximal small loop epitope of CD20 can effectively eliminate CD20 low expressing tumor cells that resist rituximab-mediated lysis. Haematologica, 2010. 95(12): p. 2063-71. Disclosures Hiemstra: Genmab: Employment, Other: Warrants. Engelberts:Genmab: Employment, Other: Warrants. de Jong:Genmab: Employment, Other: Warrants. Schuurhuis:Genmab: Employment, Other: Warrants. Salcedo:Genmab: Employment, Other: Warrants. Verploegen:Genmab: Employment, Equity Ownership. van der Zee:Genmab: Employment, Other: Warrants. Gerritsen:Genmab: Employment, Other: Warrants. Losic:Genmab: Employment, Other: Warrants. Horbach:Genmab: Employment, Other: Warrants. Oliveri:Genmab: Employment, Other: Warrants. Lammerts van Bueren:Genmab: Employment, Other: Warrants. Autzen Usher:Genmab: Employment, Other: Warrants. Schuurman:Genmab: Employment, Other: Warrants. Parren:Genmab: Equity Ownership; Lava Therapeutics: Employment. Breij:Genmab: Employment, Equity Ownership.

B-Cell Depletion In Vitro and In Vivo with an Afucosylated Anti-CD19 Antibody

2010 ◽  
Vol 335 (1) ◽  
pp. 213-222 ◽  
Author(s):  
Ronald Herbst ◽  
Yue Wang ◽  
Sandra Gallagher ◽  
Nanette Mittereder ◽  
Ellen Kuta ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Depletion ◽  
B Cell Depletion

CD20 Antibodies of Human IgA Isotype Mediate CDC, and ADCC By Myeloid Effector Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1835-1835 ◽  
Author(s):  
Anna Kretschmer ◽  
Stefan Lohse ◽  
Thies Rösner ◽  
Marco J.H. Jansen ◽  
Christian Kellner ◽  
...  
Keyword(s):  
B Cell ◽  
Research Funding ◽  
Cell Depletion ◽  
Type I ◽  
B Cell Depletion ◽  
Lymphoma Cells ◽  
Knock Out ◽  
Cd20 Antibodies

Abstract Introduction: Three unconjugated CD20 antibodies have been approved for the treatment of lymphoma patients. All three are of human IgG1 isotype, but nevertheless they differ in their modes of action: type I antibodies (e.g. rituximab and ofatumumab) trigger effective complement-dependent cytotoxicity (CDC), whereas type II antibodies (e.g. obinutuzumab) are potent inducers of direct cell death, while both type I and II antibodies can induce antibody-dependent cellular cytotoxicity (ADCC). Studies in syngeneic mouse models suggest that myeloid cells are the predominant effector cell type for CD20 antibodies (Uchida et al. J Exp Med 199:1659, 2004). However, human myeloid cells, particularly PMN, are activated more effectively by human IgA than by IgG1 antibodies (Dechant et al. Blood 100:4574, 2002) - especially when the latter are engineered for enhanced FcγRIII affinity (Peipp et al. Blood 112:2390, 2008). Antibodies of IgA isotype constitute an integral part of the mucosal immune system, and differ from IgG antibodies in their pharmacokinetic properties and immune effector mechanisms (Boross et al. EMBO Mol Med 5:1213, 2013, Lohse et al. Cancer Res 76:403, 2016). Here, we compared the efficiency of IgG1 and IgA2 isotype variants of the type I CD20 antibody 1F5 in killing lymphoma cells in vitro and in vivo. Methods: Recombinant antibodies against human CD20 were produced by co-transfecting BHK cells with vectors encoding the 1F5 variable, Igα2 or Igγ1 heavy, and κ light chain constant regions, respectively. The resulting isotype variants were compared for their biochemical characteristics as well as Fab- and Fc- mediated effector functions using human lymphoma cell lines as targets. NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice xenotransplanted with human RAJI lymphoma cells were employed to investigate the therapeutic efficacy of human CD20 antibodies. Additionally, in vivo depletion of human CD20 transgenic B cells was evaluated in a syngeneic B cell depletion model using wildtype, human FcαRI transgenic and C3 knock-out mice. Results and Discussion: In vivo studies with xenotransplanted RAJI cells in NSG mice, which lack functional T and NK cells, demonstrated significantly prolonged survival of treated as compared to non-treated mice, indicating that myeloid effector cells may contribute to the therapeutic efficacy of CD20 antibodies against human lymphoma cells. In vitro, neither IgG1 nor IgA2 variants of 1F5 showed efficient Fab-mediated effects such as direct cell death induction and homotypic aggregation compared to type II antibodies. However, human IgA2 but not IgG1 antibody variants against CD20 effectively triggered ADCC by human PMN, the most numerous myeloid effector cell population. Although IgA does not bind C1q, CD20 IgA antibodies also triggered CDC against several lymphoma cell lines. CDC was predominantly mediated by the alternative pathway, as evidenced by the kinetics of lysis, the requirement for higher serum concentrations and inhibition by the C3 inhibitor compstatin. Further in vivo experiments demonstrated that 1F5-IgA2 effectively depleted B cells in a syngeneic human CD20 transgenic B cell depletion model. However, studies in human FcαRI transgenic or C3 knock-out mice indicated that B cell depletion was not mediated by FcαRI or complement - suggesting that other currently undefined mechanisms contribute to the in vivo efficacy of IgA antibodies against CD20. Conclusions: Together, the presented results suggest that CD20 antibodies of human IgA isotype constitute promising immunotherapeutic reagents with unique effector functions. Additional studies are required to further elucidate their effector mechanisms in vitro and in vivo. Disclosures Cragg: Roche: Consultancy, Research Funding; Gilead Sciences: Research Funding; Baxalta: Consultancy; Bioinvent International: Consultancy, Research Funding; GSK: Research Funding.

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