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.

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.

scholarly journals Comparison of Ibrutinib, Idelalisib and Olaptesed Pegol on the Immune Effector Function Mediated By Rituximab

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4499-4499
Author(s):  
Dirk Zboralski ◽  
Axel Vater ◽  
Anna Kruschinski
Keyword(s):  
B Cell ◽  
Cell Activation ◽  
Kinase Inhibitors ◽  
Immune Cell ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Malignant Cells ◽  
Immune Effector ◽  
Effector Cells ◽  
Calcein Release

Abstract Olaptesed pegol (NOX-A12), an SDF-1 binding Spiegelmer® was found to detach SDF-1 from the surface of BMSCs (Hoellenriegel et al., Blood 2013) and to mobilize CXCR4 expressing, malignant cells from protective niches in the bone marrow or other secondary lymphoid tissues, thereby sensitizing them to the action of standard therapy. In addition to malignant cells CXCR4 expressing immune cells, e.g. T cells, neutrophils and monocytes are effectively mobilized by olaptesed (Vater et al., Clin Pharmacol Ther 2013). Here we investigated the combination of olaptesed with an immunotherapeutic agent, in particular rituximab (RTX). Several mechanisms of action (MoA) of RTX have been described including antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). The aim was to analyze whether olaptesed influences the immune effector cell activation by RTX as has been shown for the Btk or PI3Kd inhibitors ibrutinib and idelalisib, respectively. ADCC activity was measured by the calcein release assay. Raji lymphoma cells were labeled with calcein, treated with 10 µg/mL RTX and co-cultured for 4 hours with various ratios of PBMCs as effector cells, which have been incubated with either 10 µM olaptesed, 1 µM ibrutinib or 1 µM idelalisib, respectively, overnight. In order to analyze the impact on phagocyte function, ADCP assays with neutrophils and monocytes were performed. Phagocytes were preincubated with either 10 µM olaptesed, 1 µM ibrutinib or 1 µM idelalisib, respectively, for 6 hours, and cocultured overnight with DiD-labeled primary B-cells or Raji cells which were opsonized with different concentrations of RTX. ADCP was quantified in a guava easyCyte flow cytometer by counting the CD15+ (or CD14+) and DiD+ population (gated on CD19-negative cells) and normalizing to total phagocyte counts. To analyze B-cell depletion, heparinized whole blood from healthy volunteers was diluted with HBSS (1:2.5) and incubated with either 10 µM olaptesed, 1 µM ibrutinib or 1µM idelalisib, respectively, for 6 hours followed by the addition of different RTX concentrations. After incubation for 16 hours B-cell depletion was evaluated by determining the CD19+ B-cell and CD3+ T-cell populations. We found that preincubation of PBMCs with 1 µM ibrutinib significantly decreased calcein release. 1 µM idelalisib led to a slight decrease of calcein release, while 10 µM olaptesed did not influence ADCC activity (Figure 1A). Preliminary results from ADCP assays point to a decreased phagocytic activity in terms of maximal ADCP for neutrophils after preincubation with ibrutinib or idelalisib (Figure 1B). Importantly, although olaptesed is being endocytosed by phagocytes, the uptake of the drug did not inhibit ADCP. In accordance, the whole blood assay showed that olaptesed had no negative impact on RTX-mediated B-cell depletion, while ibrutinib and idelalisib were found to decrease B-cell depletion regarding EC50 and maximal killing (Figure 1C). Taken together, we found that olaptesed retains the immune functional repertoire of RTX, whereas ibrutinib and idelalisib decrease the immune effector function. These small molecule kinase inhibitors possess low specificity and are inhibiting also other kinases which may be important for immune cell activation, such as ITK which is blocked by ibrutinib. The MoA of olaptesed is partially overlapping with kinase inhibitors with regard to lymphoid cell mobilization; however, olaptesed is highly selective and therefore does not impair immune-cell mediated contribution to monoclonal antibody efficacy. Instead, olaptesed may further enhance the contribution of immune effector cells through mobilization of T cells from the bone marrow which are described to be exhausted in the peripheral blood of hematological malignancies like CLL. Furthermore, neutrophils and monocytes which contribute to ADCP are effectively mobilized with olaptesed. Based on their complementary mechanisms of action involving direct and immune-mediated cell death (RTX) or long-term mobilization of not only the malignant cells but also effector immune cells (olaptesed), the combination has the potential for greater efficacy in treating B lymphoid malignancies without impairing immune effector activity. Olaptesed is currently being tested in a Phase 2a clinical trial in combination with RTX and bendamustine in patients with relapsed/refractory CLL (#NCT01486797). Figure 1 Figure 1. Disclosures Zboralski: NOXXON Pharma AG: Employment. Vater:NOXXON Pharma AG: Employment. Kruschinski:NOXXON Pharma AG: 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 Humoral and T-cell responses to SARS-CoV-2 vaccination in patients receiving immunosuppression

2021 ◽  
pp. annrheumdis-2021-220626
Author(s):  
Maria Prendecki ◽  
Candice Clarke ◽  
Helena Edwards ◽  
Stacey McIntyre ◽  
Paige Mortimer ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
T Cell Responses ◽  
T Cell Response ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Glomerular Diseases ◽  
Cell Responses ◽  
The Impact ◽  
Dose Vaccine

ObjectiveThere is an urgent need to assess the impact of immunosuppressive therapies on the immunogenicity and efficacy of SARS-CoV-2 vaccination.MethodsSerological and T-cell ELISpot assays were used to assess the response to first-dose and second-dose SARS-CoV-2 vaccine (with either BNT162b2 mRNA or ChAdOx1 nCoV-19 vaccines) in 140 participants receiving immunosuppression for autoimmune rheumatic and glomerular diseases.ResultsFollowing first-dose vaccine, 28.6% (34/119) of infection-naïve participants seroconverted and 26.0% (13/50) had detectable T-cell responses to SARS-CoV-2. Immune responses were augmented by second-dose vaccine, increasing seroconversion and T-cell response rates to 59.3% (54/91) and 82.6% (38/46), respectively. B-cell depletion at the time of vaccination was associated with failure to seroconvert, and tacrolimus therapy was associated with diminished T-cell responses. Reassuringly, only 8.7% of infection-naïve patients had neither antibody nor T-cell responses detected following second-dose vaccine. In patients with evidence of prior SARS-CoV-2 infection (19/140), all mounted high-titre antibody responses after first-dose vaccine, regardless of immunosuppressive therapy.ConclusionSARS-CoV-2 vaccines are immunogenic in patients receiving immunosuppression, when assessed by a combination of serology and cell-based assays, although the response is impaired compared with healthy individuals. B-cell depletion following rituximab impairs serological responses, but T-cell responses are preserved in this group. We suggest that repeat vaccine doses for serological non-responders should be investigated as means to induce more robust immunological response.

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.

scholarly journals Effects of B Cell Depletion on Early Mycobacterium tuberculosis Infection in Cynomolgus Macaques

2016 ◽  
Vol 84 (5) ◽  
pp. 1301-1311 ◽  
Author(s):  
Jiayao Phuah ◽  
Eileen A. Wong ◽  
Hannah P. Gideon ◽  
Pauline Maiello ◽  
M. Teresa Coleman ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
B Cells ◽  
B Cell ◽  
Humoral Immunity ◽  
Nonhuman Primates ◽  
Acute Infection ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Content Type ◽  
The Impact

Although recent studies in mice have shown that components of B cell and humoral immunity can modulate the immune responses againstMycobacterium tuberculosis, the roles of these components in human and nonhuman primate infections are unknown. The cynomolgus macaque (Macaca fascicularis) model ofM. tuberculosisinfection closely mirrors the infection outcomes and pathology in human tuberculosis (TB). The present study used rituximab, an anti-CD20 antibody, to deplete B cells inM. tuberculosis-infected macaques to examine the contribution of B cells and humoral immunity to the control of TB in nonhuman primates during the acute phase of infection. While there was no difference in the overall pathology, disease profession, and clinical outcome between the rituximab-treated and untreated macaques in acute infection, analyzing individual granulomas revealed that B cell depletion resulted in altered local T cell and cytokine responses, increased bacterial burden, and lower levels of inflammation. There were elevated frequencies of T cells producing interleukin-2 (IL-2), IL-10, and IL-17 and decreased IL-6 and IL-10 levels within granulomas from B cell-depleted animals. The effects of B cell depletion varied among granulomas in an individual animal, as well as among animals, underscoring the previously reported heterogeneity of local immunologic characteristics of tuberculous granulomas in nonhuman primates. Taken together, our data clearly showed that B cells can modulate the local granulomatous response inM. tuberculosis-infected macaques during acute infection. The impact of these alterations on disease progression and outcome in the chronic phase remains to be determined.

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

scholarly journals Increasing the efficacy of CD20 antibody therapy through the engineering of a new type II anti-CD20 antibody with enhanced direct and immune effector cell–mediated B-cell cytotoxicity

Blood ◽  
2010 ◽  
Vol 115 (22) ◽  
pp. 4393-4402 ◽  
Author(s):  
Ekkehard Mössner ◽  
Peter Brünker ◽  
Samuel Moser ◽  
Ursula Püntener ◽  
Carla Schmidt ◽  
...  
Keyword(s):  
Overall Survival ◽  
B Cell ◽  
Effector Cell ◽  
Antibody Therapy ◽  
Cell Depletion ◽  
Type Ii ◽  
B Cell Depletion ◽  
Immune Effector Cell ◽  
Immune Effector ◽  
Cd20 Antibody

AbstractCD20 is an important target for the treatment of B-cell malignancies, including non-Hodgkin lymphoma as well as autoimmune disorders. B-cell depletion therapy using monoclonal antibodies against CD20, such as rituximab, has revolutionized the treatment of these disorders, greatly improving overall survival in patients. Here, we report the development of GA101 as the first Fc-engineered, type II humanized IgG1 antibody against CD20. Relative to rituximab, GA101 has increased direct and immune effector cell-mediated cytotoxicity and exhibits superior activity in cellular assays and whole blood B-cell depletion assays. In human lymphoma xenograft models, GA101 exhibits superior antitumor activity, resulting in the induction of complete tumor remission and increased overall survival. In nonhuman primates, GA101 demonstrates superior B cell–depleting activity in lymphoid tissue, including in lymph nodes and spleen. Taken together, these results provide compelling evidence for the development of GA101 as a promising new therapy for the treatment of B-cell disorders.

The impact of Fc engineering on an anti-CD19 antibody: increased Fcγ receptor affinity enhances B-cell clearing in nonhuman primates

Blood ◽  
2009 ◽  
Vol 113 (16) ◽  
pp. 3735-3743 ◽  
Author(s):  
Jonathan Zalevsky ◽  
Irene W. L. Leung ◽  
Sher Karki ◽  
Seung Y. Chu ◽  
Eugene A. Zhukovsky ◽  
...  
Keyword(s):  
B Cell ◽  
Nk Cells ◽  
Binding Affinity ◽  
Effector Cell ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Fcγ Receptor ◽  
B Cell Malignancies ◽  
Cell Functions ◽  
The Impact

Abstract CD19, a B cell–restricted receptor critical for B-cell development, is expressed in most B-cell malignancies. The Fc-engineered anti-CD19 antibody, XmAb5574, has enhanced Fcγ receptor (FcγR) binding affinity, leading to improved FcγR-dependent effector cell functions and antitumor activity in murine xenografts compared with the non–Fc-engineered anti-CD19 IgG1 analog. Here, we use XmAb5574 and anti-CD19 IgG1 to further dissect effector cell functions in an immune system closely homologous to that of humans, the cynomolgus monkey. XmAb5574 infusion caused an immediate and dose-related B-cell depletion in the blood (to <10% of baseline levels) concomitant with a sustained reduction of natural killer (NK) cells. NK cells had fully recovered by day 15, whereas B-cell recovery was underway by day 57. B cells in secondary lymphoid tissues were depleted (to 34%-61% of vehicle), with involuted germinal centers apparent in the spleen. Anti-CD19 IgG1 had comparable serum exposure to XmAb5574 but demonstrated no B-cell depletion and no sustained NK-cell reduction. Thus, increasing FcγR binding affinity dramatically increased B-cell clearing. We propose that effector cell functions, possibly those involving NK cells, mediate XmAb5574 potency in cynomolgus monkeys, and that enhancing these mechanisms should advance the treatment of B-cell malignancies in humans.

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