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Nonclinical safety evaluation of pabinafusp alfa, an anti-human transferrin receptor antibody and iduronate-2-sulfatase fusion protein, for the treatment of neuronopathic mucopolysaccharidosis type II. Mol Genet Metab Rep 2021; 27:100758. [PMID: 33981582 PMCID: PMC8081988 DOI: 10.1016/j.ymgmr.2021.100758] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
Pabinafusp alfa is a fusion protein comprising a humanized anti-human transferrin receptor (TfR) antibody and human iduronate-2-sulfatase. It was developed as a novel modality to target central nervous system-related symptoms observed in patients with mucopolysaccharidosis type II (MPS II, also known as Hunter syndrome). As the fusion protein contains an entire IgG1 molecule that binds TfR, there may be specific safety concerns, such as unexpected cellular toxicity due to its effector functions or its ability to inhibit iron metabolism, in addition to general safety concerns. Here, we present the comprehensive results of a nonclinical safety assessment of pabinafusp alfa. Pabinafusp alfa did not exhibit effector functions, as assessed by antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity studies in TfR-expressing hematopoietic cells. Repeat-dose toxicity studies in cynomolgus monkeys showed that pabinafusp alfa did not induce any significant toxicological changes at doses up to 30 mg/kg/week upon intravenous administration for up to 26 weeks. Interaction of transferrin with TfR was not inhibited by pabinafusp alfa, suggesting that the effect of pabinafusp alfa on the physiological iron transport system is minimal, which was confirmed by toxicity studies in cynomolgus monkeys. These findings suggest that pabinafusp alfa is expected to be safe for long-term use in individuals with MPS II.
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Key Words
- ADA, anti-drug antibody
- ADCC, antibody-dependent cellular cytotoxicity
- Anti-transferrin receptor antibody
- Antibody-dependent cellular cytotoxicity
- BBB, blood-brain barrier
- CDC, complement-dependent cytotoxicity
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Complement-dependent cytotoxicity
- ERT, enzyme-replacement therapy
- Effector function
- FOB, functional observational battery
- Fc, fragment crystalizable
- GAG, glycosaminoglycan
- Hb, hemoglobin
- Ht, hematocrit
- IDS, iduronate-2-sulfatase
- MCH, mean corpuscular hemoglobin
- MCHC, mean corpuscular hemoglobin concentration
- MPS II, mucopolysaccharidosis type II
- Mucopolysaccharidosis type II
- NOAEL, no observed adverse effect level
- QWBA, quantitative whole-body autoradioluminography
- RBC, red blood cell
- Ret, reticulocyte
- TK, toxicokinetics
- Tf, transferrin
- TfR, transferrin receptor
- Toxicity
- mAb, monoclonal antibody
- pAb, polyclonal antibody
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Establishment of a novel anti-TROP2 monoclonal antibody TrMab-29 for immunohistochemical analysis. Biochem Biophys Rep 2021; 25:100902. [PMID: 33490649 PMCID: PMC7806523 DOI: 10.1016/j.bbrep.2020.100902] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/08/2020] [Accepted: 12/27/2020] [Indexed: 12/28/2022] Open
Abstract
TROP2 is a type I transmembrane glycoprotein originally identified in human trophoblast cells that is overexpressed in several types of cancer. To better understand the role of TROP2 in cancer, we herein aimed to develop a sensitive and specific anti-TROP2 monoclonal antibody (mAb) for use in flow cytometry, Western blot, and immunohistochemistry using a Cell-Based Immunization and Screening (CBIS) method. Two mice were immunized with N-terminal PA-tagged and C-terminal RAP/MAP-tagged TROP2-overexpressed Chinese hamster ovary (CHO)-K1 cells (CHO/PA-TROP2-RAP-MAP), and hybridomas showing strong signals from PA-tagged TROP2-overexpressed CHO-K1 cells (CHO/TROP2-PA) and weak-to-no signals from CHO-K1 cells were selected using flow cytometry. We demonstrated using flow cytometry that the established anti-TROP2 mAb, TrMab-29 (mouse IgG1 kappa), detected TROP2 in MCF7 breast cancer cell line as well as CHO/TROP2-PA cells. Western blot analysis showed a 40 kDa band in lysates prepared from both CHO/TROP2-PA and MCF7 cells. Furthermore, TROP2 was strongly detected by immunohistochemical analysis using TrMab-29, indicating that TrMab-29 may be a valuable tool for the detection of TROP2 in cancer.
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Key Words
- ADC, antibody-drug conjugates
- ADCC, antibody-dependent cellular cytotoxicity
- BSA, bovine serum albumin
- Breast cancer
- CAR-T, chimeric antigen receptor T-cell
- CBIS method
- CBIS, Cell-Based Immunization and Screening
- CDC, complement-dependent cytotoxicity
- CHO, Chinese hamster ovary
- DAB, 3,3′-diaminobenzidine tetrahydrochloride
- Monoclonal antibody
- P3U1, P3X63Ag8U.1
- PBS, phosphate-buffered saline
- PIT, photoimmunotherapy
- PVDF, polyvinylidene difluoride
- RIT, radioimmunotherapy
- TROP2
- TROP2, trophoblast cell-surface antigen
- mAb, monoclonal antibody
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A cancer-specific anti-podocalyxin monoclonal antibody (60-mG 2a-f) exerts antitumor effects in mouse xenograft models of pancreatic carcinoma. Biochem Biophys Rep 2020; 24:100826. [PMID: 33088928 PMCID: PMC7559861 DOI: 10.1016/j.bbrep.2020.100826] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/22/2020] [Accepted: 10/07/2020] [Indexed: 01/22/2023] Open
Abstract
Overexpression of podocalyxin (PODXL) is associated with progression, metastasis, and poor outcomes in several cancers. PODXL also plays an important role in the development of normal tissues. For antibody-based therapy to target PODXL-expressing cancers using monoclonal antibodies (mAbs), cancer-specificity is necessary to reduce the risk of adverse effects to normal tissues. In this study, we developed an anti-PODXL cancer-specific mAb (CasMab), named as PcMab-60 (IgM, kappa) by immunizing mice with soluble PODXL, which is overexpressed in LN229 glioblastoma cells. The PcMab-60 reacted with the PODXL-overexpressing LN229 (LN229/PODXL) cells and MIA PaCa-2 pancreatic cancer cells in flow cytometry but did not react with normal vascular endothelial cells (VECs), whereas one of non-CasMabs, PcMab-47 showed high reactivity for not only LN229/PODXL and MIA PaCa-2 cells but also VECs, indicating that PcMab-60 is a CasMab. Next, we engineered PcMab-60 into a mouse IgG2a-type mAb, named as 60-mG2a, to add antibody-dependent cellular cytotoxicity (ADCC). We further developed a core fucose-deficient type of 60-mG2a, named as 60-mG2a-f, to augment its ADCC activity. In vivo analysis revealed that 60-mG2a-f exerted antitumor activity in MIA PaCa-2 xenograft models at a dose of 100 μg/mouse/week administered three times. These results suggested that 60-mG2a-f could be useful for antibody-based therapy against PODXL-expressing pancreatic cancers. PODXL is associated with poor outcomes in several cancers. We developed an anti-PODXL cancer-specific mAb (PcMab-60). A core fucose-deficient IgG2a type of PcMab-60 (60-mG2a-f) exerted antitumor activity in MIA PaCa-2 xenograft models. 60-mG2a-f could be useful for antibody-based therapy against PODXL-expressing pancreatic cancers.
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The mouse-canine chimeric anti-dog podoplanin antibody P38B exerts antitumor activity in mouse xenograft models. Biochem Biophys Rep 2018; 17:23-26. [PMID: 30519645 PMCID: PMC6260363 DOI: 10.1016/j.bbrep.2018.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 11/14/2018] [Indexed: 12/19/2022] Open
Abstract
Podoplanin (PDPN) is a type I transmembrane heavily glycosylated sialoglycoprotein that is expressed in normal tissues such as pulmonary type I alveolar cells, renal podocytes, and lymphatic endothelial cells. PDPN overexpression in cancerous tissue is associated with hematogenous metastasis through interactions with the C-type lectin-like receptor 2 (CLEC-2). Previously, we have reported the development of a mouse monoclonal antibody (mAb), PMab-38 (IgG1, kappa) against dog PDPN (dPDPN). PMab-38 was found to strongly react with canine squamous cell carcinomas (SCCs) and melanomas; however, it showed no reaction with lymphatic endothelial cells. Recently, we have developed and produced the mouse–canine mAb of subclass B, P38B that showed antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against Chinese hamster ovary (CHO)/dPDPN cells. In the present study, we investigated the antitumor activity using mouse xenograft model. To induce ADCC activity by P38B, canine mononuclear cells were injected surrounding the tumors in a xenograft model. It was demonstrated that P38B exerted antitumor activity against the mouse xenograft model using CHO/dPDPN. These results suggest that P38B is useful for antibody therapy against dPDPN-expressing canine SCCs and melanomas. Dog PDPN is expressed in canine squamous cell carcinomas and melanomas. A mouse-canine mAb of canine subclass B, P38B against dog PDPN was produced. P38B exerted antitumor activities via ADCC and CDC. P38B could be useful for antibody therapy against dPDPN-expressing canine tumors.
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The criticality of high-resolution N-linked carbohydrate assays and detailed characterization of antibody effector function in the context of biosimilar development. MAbs 2016; 7:562-70. [PMID: 25898160 DOI: 10.1080/19420862.2015.1016692] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Accurate measurement and functional characterization of antibody Fc domain N-linked glycans is critical to successful biosimilar development. Here, we describe the application of methods to accurately quantify and characterize the N-linked glycans of 2 IgG1 biosimilars with effector function activity, and show the potential pitfalls of using assays with insufficient resolution. Accurate glycan assessment was combined with glycan enrichment using lectin chromatography or production with glycosylation inhibitors to produce enriched pools of key glycan species for subsequent assessment in cell-based antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity effector function assays. This work highlights the challenges of developing high-quality biosimilar candidates and the need for modern biotechnology capabilities. These results show that high-quality analytics, combined with sensitive cell-based assays to study in vivo mechanisms of action, is an essential part of biosimilar development.
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Key Words
- ACN, acetonitrile
- ADCC
- ADCC, antibody-dependent cell-mediated cytotoxicity
- AHGs, afucosylated hybrid glycans
- AMBGs, afucosylated monoantennary and biantennary glycans
- BGGs, β-galactosylated glycans
- CDC
- CDC, complement-dependent cytotoxicity
- CHO, Chinese hamster ovary
- CQA, critical quality attribute
- Con A, concanavalin A lectin
- EIC, extracted ion current
- FT, flow-through
- Fc domain
- HC, heavy chain
- HGs, hybrid glycans
- HILIC, hydrophilic interaction liquid chromatography
- HMGs, high-mannose glycans
- HPLC, high performance liquid chromatography
- LC, light chain
- MS, mass spectrometry
- MS/MS, tandem mass spectrometry
- N-linked carbohydrates
- PQA, product quality attribute
- SGs, sialylated glycans
- SM, starting material
- TRIS, tris(hydroxymethyl)aminomethane
- antibody
- biosimilar
- effector function
- glycosylation
- mAb
- mAb, monoclonal antibody
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6
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An Fc engineering approach that modulates antibody-dependent cytokine release without altering cell-killing functions. MAbs 2016; 7:494-504. [PMID: 25933349 PMCID: PMC4622058 DOI: 10.1080/19420862.2015.1022692] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cytotoxic therapeutic monoclonal antibodies (mAbs) often mediate target cell-killing by eliciting immune effector functions via Fc region interactions with cellular and humoral components of the immune system. Key functions include antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC). However, there has been increased appreciation that along with cell-killing functions, the induction of antibody-dependent cytokine release (ADCR) can also influence disease microenvironments and therapeutic outcomes. Historically, most Fc engineering approaches have been aimed toward modulating ADCC, ADCP, or CDC. In the present study, we describe an Fc engineering approach that, while not resulting in impaired ADCC or ADCP, profoundly affects ADCR. As such, when peripheral blood mononuclear cells are used as effector cells against mAb-opsonized tumor cells, the described mAb variants elicit a similar profile and quantity of cytokines as IgG1. In contrast, although the variants elicit similar levels of tumor cell-killing as IgG1 with macrophage effector cells, the variants do not elicit macrophage-mediated ADCR against mAb-opsonized tumor cells. This study demonstrates that Fc engineering approaches can be employed to uncouple macrophage-mediated phagocytic and subsequent cell-killing functions from cytokine release.
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Key Words
- ADCC, antibody-dependent cell-mediated cytotoxicity
- ADCP, antibody-dependent cellular phagocytosis
- ADCR, antibody-dependent cytokine release
- APCs, antigen-presenting cells
- CDC, complement-dependent cytotoxicity
- DC, dendritic cell
- Fc gamma receptors
- FcγR, Fc gamma receptor
- IFN, interferon
- IL, interleukin
- NK, natural killer
- PBMC, peripheral blood mononuclear cell
- TNF, tumor necrosis factor
- antibody-dependent cellular phagocytosis
- cytokine release
- interferon gamma
- interleukin 10
- mAbs, monoclonal antibodies
- monocyte-derived macrophages
- natural killer cells
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7
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Development of a heat-stable and orally delivered recombinant M2e-expressing B. subtilis spore-based influenza vaccine. Hum Vaccin Immunother 2015; 10:3649-58. [PMID: 25483702 DOI: 10.4161/hv.36122] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Highly conserved ectodomain of influenza virus M2 protein (M2e) is an important target for the development of universal influenza vaccines. Today, the use of chemical or genetic fusion constructs have been undertaken to overcome the low immunogenicity of M2e in vaccine formulation. However, current M2e vaccines are neither orally delivered nor heat-stable. In this study, we evaluated the immune efficacy of an orally delivered recombinant M2e vaccine containing 3 molcules of M2e consensus sequence of influenza A viruses, termed RSM2e3. To accomplish this, CotB, a spore coat of Bacillus subtilis (B. subtilis), was used as a fusion partner, and heat-stable nonpathogenic B. subtilis spores were used as the carrier. Our results showed that CotB-M2e3 fusion had no effect on spore structure or function in the resultant recombinant RSM2e3 strain and that heterologous influenza virus M2e protein was successfully displayed on the surface of the recombinant RSM2e3 spore. Importantly, recombinant RSM2e3 spores elicited strong and long-term M2e-specific systemic and mucosal immune responses, completely protecting immunized mice from lethal challenge of A/PR/8/34(H1N1) influenza virus. Taken together, our study forms a solid basis for the development of a novel orally delivered and heat-stable influenza vaccine based on B. subtilis spore surface display.
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High contrast tumor imaging with radio-labeled antibody Fab fragments tailored for optimized pharmacokinetics via PASylation. MAbs 2015; 7:96-109. [PMID: 25484039 PMCID: PMC4622060 DOI: 10.4161/19420862.2014.985522] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although antigen-binding fragments (Fabs) of antibodies constitute established tracers for in vivo radiodiagnostics, their functionality is hampered by a very short circulation half-life. PASylation, the genetic fusion with a long, conformationally disordered amino acid chain comprising Pro, Ala and Ser, provides a convenient way to expand protein size and, consequently, retard renal filtration. Humanized αHER2 and αCD20 Fabs were systematically fused with 100 to 600 PAS residues and produced in E. coli. Cytofluorimetric titration analysis on tumor cell lines confirmed that antigen-binding activities of the parental antibodies were retained. The radio-iodinated PASylated Fabs were studied by positron emission tomography (PET) imaging and biodistribution analysis in mouse tumor xenograft models. While the unmodified αHER2 and αCD20 Fabs showed weak tumor uptake (0.8% and 0.2% ID/g, respectively; 24 h p.i.) tumor-associated radioactivity was boosted with increasing PAS length (up to 9 and 26-fold, respectively), approaching an optimum for Fab-PAS400. Remarkably, 6- and 5-fold higher tumor-to-blood ratios compared with the unmodified Fabs were measured in the biodistribution analysis (48 h p.i.) for αHER2 Fab-PAS100 and Fab-PAS200, respectively. These findings were confirmed by PET studies, showing high imaging contrast in line with tumor-to-blood ratios of 12.2 and 5.7 (24 h p.i.) for αHER2 Fab-PAS100 and Fab-PAS200. Even stronger tumor signals were obtained with the corresponding αCD20 Fabs, both in PET imaging and biodistribution analysis, with an uptake of 2.8% ID/g for Fab-PAS100vs. 0.24% ID/g for the unmodified Fab. Hence, by engineering Fabs via PASylation, plasma half-life can be tailored to significantly improve tracer uptake and tumor contrast, thus optimally matching reagent/target interactions.
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Key Words
- ABD, albumin binding domain
- CD20
- CDC, complement-dependent cytotoxicity
- CDR, complementarity-determining region
- CLL, chronic lymphocytic leukemia
- DMEM, Dulbecco's modified Eagle medium
- EPR, enhanced permeability and retention effect
- FACS, fluorescence-activated cell sorting
- FBS, fetal bovine serum
- Fab, antigen-binding fragment
- FcRn, neonatal Fc receptor
- HER2
- HER2, human epidermal growth factor receptor 2
- ID, injected dose
- IDA, iminodiacetic acid
- Ig, immunoglobulin
- MIP, maximum intensity projection
- NHL, non-Hodgkin lymphoma
- PEGylation
- PET, positron emission tomography
- PK, pharmacokinetics
- RIT, radioimmuno therapy
- SEC, size exclusion chromatography
- SPECT, single photon emission computed tomography
- TLC, thin layer chromatography
- antibody fragment
- mAb, monoclonal antibody
- p.i., post injection
- plasma half-life
- protein tracer
- scFv, single-chain variable antibody fragment
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Neutralization of membrane complement regulators improves complement-dependent effector functions of therapeutic anticancer antibodies targeting leukemic cells. Oncoimmunology 2015; 4:e979688. [PMID: 25949896 PMCID: PMC4404820 DOI: 10.4161/2162402x.2014.979688] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 01/12/2023] Open
Abstract
Complement-dependent cytotoxicity (CDC) is one of the effector mechanisms mediated by therapeutic anticancer monoclonal antibodies (mAbs). However, the efficacy of antibodies is limited by the resistance of malignant cells to complement attack, primarily due to the over-expression of one or more membrane complement regulatory proteins (mCRPs) CD46, CD55, and CD59. CD20-positive Burkitt lymphoma Raji cells and primary CLL cells are resistant to rituximab (RTX)-induced CDC whereas ofatumumab (OFA) proved to be more efficient in cell killing. Primary CLL cells but not CD52-positive acute lymphoblastic leukemia (ALL) REH cells were sensitive to alemtuzumab (ALM)-induced CDC. Upon combined inhibition on Raji and CLL cells by mCRPs-specific siRNAs or neutralizing antibodies, CDC induced by RTX and by OFA was augmented. Similarly, CDC of REH cells was enhanced after mCRPs were inhibited upon treatment with ALM. All mAbs induced C3 opsonization, which was significantly augmented upon blocking mCRPs. C3 opsonization led to enhanced cell-mediated cytotoxicity of leukemia cells exposed to PBLs or macrophages. Furthermore, opsonized CLL cells were efficiently phagocytized by macrophages. Our results provide conclusive evidence that inhibition of mCRPs expression sensitizes leukemic cells to complement attack thereby enhancing the therapeutic effect of mAbs targeting leukemic cells.
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Key Words
- ADCC, antibody-dependent cellular cytotoxicity
- ALM, Alemtuzumab
- CDC, complement-dependent cytotoxicity
- CDCC, complement-dependent cellular cytotoxicity
- MAC, membrane attack complex
- NHS, Normal Human Serum
- OFA, Ofatumumab
- PBLs, peripheral blood leukocytes
- RTX, Rituximab
- TRX, Trastuzumab
- alemtuzumab
- chronic lymphocytic leukemia
- complement regulatory proteins
- complement-dependent cytotoxicity
- mCRP, membrane-bound complement regulatory protein
- ofatumumab
- opsonization
- rituximab
- siRNA, small interfering RNA
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Preclinical and early clinical development of GNbAC1, a humanized IgG4 monoclonal antibody targeting endogenous retroviral MSRV-Env protein. MAbs 2015; 7:265-75. [PMID: 25427053 PMCID: PMC4623301 DOI: 10.4161/19420862.2014.985021] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/15/2014] [Accepted: 10/31/2014] [Indexed: 11/19/2022] Open
Abstract
Monoclonal antibodies (mAbs) play an increasing important role in the therapeutic armamentarium against multiple sclerosis (MS), an inflammatory and degenerative disorder of the central nervous system. Most of the mAbs currently developed for MS are immunomodulators blocking the inflammatory immune process. In contrast with mAbs targeting immune function, GNbAC1, a humanized IgG4 mAb, targets the multiple sclerosis associated retrovirus envelope (MSRV-Env) protein, an upstream factor in the pathophysiology of MS. MSRV-Env protein is of endogenous retroviral origin, expressed in MS brain lesions, and it is pro-inflammatory and toxic to the remyelination process, by preventing the differentiation of oligodendrocyte precursor cells. We present the preclinical and early clinical development results of GNbAC1. The specificity of GNbAC1 for its endogenous retroviral target is described. Efficacy of different mAb versions of GNbAC1 were assessed in MSRV-Env induced experimental allergic encephalitis (EAE), an animal model of MS. Because the target MSRV-Env is not expressed in animals, no relevant animal model exists for a proper in vivo toxicological program. An off-target 2-week toxicity study in mice was thus performed, and it showed an absence of safety risk. Additional in vitro analyses showed an absence of complement or antibody-dependent cytotoxicity as well as a low level of cross-reactivity to human tissues. The first-in-man clinical study in 33 healthy subjects and a long-term clinical study in 10 MS patients showed that GNbAC1 is well tolerated in humans without induction of immunogenicity and that it induces a pharmacodynamic response on MSRV biomarkers. These initial results suggest that the mAb GNbAC1 could be a safe long-term treatment for patients with MS with a unique therapeutic mechanism of action.
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Key Words
- ADCC, antibody-dependent cell-mediated cytotoxicity
- AE, adverse events
- AUC, area under the curve
- BLAST, Basic Local Alignment Search Tool
- CDC, complement-dependent cytotoxicity
- CDR, complementarity-determining regions
- Cmax, maximal concentration
- Cmin, minimal concentration
- HERV-W
- HERV-W, human endogenous retrovirus type W
- HLA, human leukocyte antigen
- MOG, myelin oligodendrocyte glycoprotein
- MS, multiple sclerosis
- MSRV
- MSRV, multiple sclerosis associated retrovirus
- MSRV-Env, multiple sclerosis associated retrovirus envelope protein
- PBMC, peripheral blood mononuclear cell
- SAE, serious adverse event
- SU, surface domain
- Syncytin
- TLR4, Toll-like receptor 4
- ch-GNbAC1, chimeric version of mAb GNbAC1
- drug safety
- human endogenous retrovirus
- mAb, monoclonal antibody
- monoclonal antibody
- mu-GNbAC1, murine version of mAb GNbAC1
- multiple sclerosis
- neurotoxicity
- toxicology
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MESH Headings
- Animals
- Antibodies, Monoclonal, Humanized/administration & dosage
- Antibodies, Monoclonal, Humanized/adverse effects
- Antibodies, Monoclonal, Humanized/immunology
- Antibody Specificity
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Endogenous Retroviruses/immunology
- Female
- Gene Products, env/immunology
- HEK293 Cells
- Humans
- Immunoglobulin G/administration & dosage
- Immunoglobulin G/adverse effects
- Immunoglobulin G/immunology
- Male
- Mice
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
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Antibody-mediated phagocytosis contributes to the anti-tumor activity of the therapeutic antibody daratumumab in lymphoma and multiple myeloma. MAbs 2015; 7:311-21. [PMID: 25760767 PMCID: PMC4622648 DOI: 10.1080/19420862.2015.1007813] [Citation(s) in RCA: 374] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/14/2014] [Accepted: 12/01/2014] [Indexed: 01/14/2023] Open
Abstract
Daratumumab (DARA) is a human CD38-specific IgG1 antibody that is in clinical development for the treatment of multiple myeloma (MM). The potential for IgG1 antibodies to induce macrophage-mediated phagocytosis, in combination with the known presence of macrophages in the tumor microenvironment in MM and other hematological tumors, led us to investigate the contribution of antibody-dependent, macrophage-mediated phagocytosis to DARA's mechanism of action. Live cell imaging revealed that DARA efficiently induced macrophage-mediated phagocytosis, in which individual macrophages rapidly and sequentially engulfed multiple tumor cells. DARA-dependent phagocytosis by mouse and human macrophages was also observed in an in vitro flow cytometry assay, using a range of MM and Burkitt's lymphoma cell lines. Phagocytosis contributed to DARA's anti-tumor activity in vivo, in both a subcutaneous and an intravenous leukemic xenograft mouse model. Finally, DARA was shown to induce macrophage-mediated phagocytosis of MM cells isolated from 11 of 12 MM patients that showed variable levels of CD38 expression. In summary, we demonstrate that phagocytosis is a fast, potent and clinically relevant mechanism of action that may contribute to the therapeutic activity of DARA in multiple myeloma and potentially other hematological tumors.
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Key Words
- ADCC, antibody-dependent cellular cytotoxicity
- BL, Burkitt's lymphoma
- BM, bone marrow
- Burkitt's lymphoma
- CCS, cosmic calf serum
- CD38
- CDC, complement-dependent cytotoxicity
- DARA, daratumumab
- DP, double positive
- E:T, effector to target ratio
- FcγR, Fc-gamma receptor
- IMiD, immunomodulatory drug
- MM, multiple myeloma
- MNC, mononuclear cells
- Mϕ, macrophage
- PBMC, peripheral blood mononuclear cells
- daratumumab
- mAb, monoclonal antibody
- macrophage
- multiple myeloma
- phagocytosis
- therapeutic antibody
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Tumor antigen-targeting monoclonal antibody-based immunotherapy: Orchestrating combined strategies for the development of long-term antitumor immunity. Oncoimmunology 2014; 3:e955684. [PMID: 25941618 DOI: 10.4161/21624011.2014.955684] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/04/2014] [Indexed: 01/09/2023] Open
Abstract
Tumor antigen (TA)-targeting monoclonal antibody (mAb)-based treatments are considered to be one of the most successful strategies in cancer therapy. Besides targeting TAs and inducing tumor cell death, such antibodies interact with immune cells through Fc-dependent mechanisms to induce adaptive memory immune responses. However, multiple inhibitory/immunosuppressive pathways can be induced by tumor cells to limit the establishment of an efficient antitumor response and consequently a sustained clinical response to TA-targeting mAbs. Here, we provide an overview on how TA-targeting mAbs in combination with conventional cancer therapies and/or inhibitors of key immunosuppressive pathways might represent promising approaches to achieve long-term tumor control.
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Key Words
- ADCC, antibody-dependent cell cytotoxicity
- ADCP, antibody-dependent cell phagocytosis
- B-NHL, B-cell non-Hodgkin's lymphoma
- CDC, complement-dependent cytotoxicity
- CTLA4, cytotoxic T-lymphocyte-associated protein 4
- DC, dendritic cell
- FDA, food and drug administration
- FcRn, neonatal Fc receptor
- HMGB1, high-mobility group box 1
- ICD, immunologic cell death
- IDO, indoleamine 2, 3-dioxygenase
- IFNγ, interferon γ
- MDSC, myeloid-derived suppressor cell
- NK, natural killer
- PD-1, programmed cell death 1
- TA, tumor antigen
- TA-targeting mAbs
- Treg, regulatory T cell
- combined therapies
- immunomodulation
- immunosuppressive pathways
- mAb, monoclonal antibody
- vaccine-like effects
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Abstract
Clinical trials with SRC family kinases (SFKs) inhibitors used alone or in a combination with anti-CD20 monoclonal antibodies (mAbs) are currently underway in the treatment of B-cell tumors. However, molecular interactions between these therapeutics have not been studied so far. A transcriptional profiling of tumor cells incubated with SFKs inhibitors revealed strong downregulation of MS4A1 gene encoding CD20 antigen. In a panel of primary and established B-cell tumors we observed that SFKs inhibitors strongly affect CD20 expression at the transcriptional level, leading to inhibition of anti-CD20 mAbs binding and increased resistance of tumor cells to complement-dependent cytotoxicity. Activation of the AKT signaling pathway significantly protected cells from dasatinib-triggered CD20 downregulation. Additionally, SFKs inhibitors suppressed antibody-dependent cell-mediated cytotoxicity by direct inhibition of natural killer cells. Abrogation of antitumor activity of rituximab was also observed in vivo in a mouse model. Noteworthy, the effects of SFKs inhibitors on NK cell function are largely reversible. The results of our studies indicate that development of optimal combinations of novel treatment modalities with anti-CD20 mAbs should be preceded by detailed preclinical evaluation of their effects on target cells.
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A monoclonal antibody against hinge-cleaved IgG restores effector function to proteolytically-inactivated IgGs in vitro and in vivo. MAbs 2014; 6:1265-73. [PMID: 25517311 DOI: 10.4161/mabs.29825] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We report a chimeric monoclonal antibody (mAb) directed to a neo-epitope that is exposed in the IgG lower hinge following proteolytic cleavage. The mAb, designated 2095-2, displays specificity for IdeS-generated F(ab')₂ fragments, but not for full-length IgG or for closely-related F(ab')₂ fragments generated with other proteases. A critical component of the specificity is provided by the C-terminal amino acid of the epitope corresponding to gly-236 in the IgG1 (also IgG4) hinge. By its ability to bind to IdeS-cleaved anti-CD20 mAb, mAb 2095-2 fully restored antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against WIL2-S cells to the otherwise inactive anti-CD20 IgG1 F(ab')₂ fragment. Similarly, 2095-2 reinstated ADCC against MDA-MB-231 cells to an anti-CD142 IgG1 F(ab')₂ fragment. mAb 2095-2 was also capable of eliciting both CDC and ADCC to IgG4 F(ab')₂ fragments, an IgG subclass that has weaker ADCC and CDC when intact relative to intact IgG1. The in vitro cell-based efficacy of 2095-2 was extended to the in vivo setting using platelets as a cell clearance surrogate. In a canine model, the co-administration of 2095-2 together with IdeS-generated, platelet-targeting anti-CD41/61 F(ab')₂ fragment not only restored platelet clearance, but did so at a rate and extent of clearance that exceeded that of intact anti-CD41/61 IgG at comparable concentrations. To further explore this unexpected amplification effect, we conducted a rat study in which 2095-2 was administered at a series of doses in combination with a fixed dose of anti-CD41/61 F(ab')₂ fragments. Again, the combination, at ratios as low as 1:10 (w/w) 2095-2 to F(ab')₂, proved more effective than the anti-CD41/61 IgG1 alone. These findings suggest a novel mechanism for enhancing antibody-mediated cell-killing effector functions with potential applications in pathologic settings such as tumors and acute infections where protease activity is abundant.
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15
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Abstract
The complement system is a powerful tool of the innate immune system to eradicate pathogens. Both in vitro and in vivo evidence indicates that therapeutic anti-tumor monoclonal antibodies (mAbs) can activate the complement system by the classical pathway. However, the contribution of complement to the efficacy of mAbs is still debated, mainly due to the lack of convincing data in patients. A beneficial role for complement during mAb therapy is supported by the fact that cancer cells often upregulate complement-regulatory proteins (CRPs). Polymorphisms in various CRPs were previously associated with complement-mediated disorders. In this review the role of complement in anti-tumor mAb therapy will be discussed with special emphasis on strategies aiming at modifying complement activity. In the future, clinical efficacy of mAbs with enhanced effector functions together with comprehensive analysis of polymorphisms in CRPs in mAb-treated patients will further clarify the role of complement in mAb therapy.
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CD137 stimulation enhances the vaccinal effect of anti-tumor antibodies. Oncoimmunology 2014; 3:e941740. [PMID: 25610724 DOI: 10.4161/21624011.2014.941740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 11/19/2022] Open
Abstract
Some evidence suggests that monoclonal antibodies (mAb) can induce an adaptive immune response against tumor cells ("vaccinal effect"). Recently, we have shown that an anti-CD137 mAb can enhance the "vaccinal effect" of an anti-tumor mAb (cetuximab), thereby transforming a passive, monoclonal, short-term immunotherapy into an active, polyclonal, long-lasting immune response.
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Key Words
- ADCC, antibody-dependent cellular cytotoxicity
- Ag, antigens
- CDC, complement-dependent cytotoxicity
- CRC, colorectal cancer
- DC, dendritic cells
- FcR, Fc receptor
- HN, head and neck
- MHC, major histocompatibility complex
- NK, natural killer
- TCR, T cell receptor
- antibody-dependent cell mediated cytotoxicity (ADCC)
- immunotherapy
- mAb, monoclonal antibodies
- monoclonal antibody
- natural killer cells
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