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1.
Immunity ; 46(4): 577-586, 2017 04 18.
Article in English | MEDLINE | ID: mdl-28410988

ABSTRACT

CD25 is expressed at high levels on regulatory T (Treg) cells and was initially proposed as a target for cancer immunotherapy. However, anti-CD25 antibodies have displayed limited activity against established tumors. We demonstrated that CD25 expression is largely restricted to tumor-infiltrating Treg cells in mice and humans. While existing anti-CD25 antibodies were observed to deplete Treg cells in the periphery, upregulation of the inhibitory Fc gamma receptor (FcγR) IIb at the tumor site prevented intra-tumoral Treg cell depletion, which may underlie the lack of anti-tumor activity previously observed in pre-clinical models. Use of an anti-CD25 antibody with enhanced binding to activating FcγRs led to effective depletion of tumor-infiltrating Treg cells, increased effector to Treg cell ratios, and improved control of established tumors. Combination with anti-programmed cell death protein-1 antibodies promoted complete tumor rejection, demonstrating the relevance of CD25 as a therapeutic target and promising substrate for future combination approaches in immune-oncology.


Subject(s)
Antibodies, Monoclonal/immunology , Immunoglobulin Fc Fragments/immunology , Interleukin-2 Receptor alpha Subunit/immunology , Neoplasms/immunology , Programmed Cell Death 1 Receptor/immunology , T-Lymphocytes, Regulatory/immunology , Animals , Antibodies, Monoclonal/metabolism , Antibodies, Monoclonal/therapeutic use , Cell Line, Tumor , Flow Cytometry , Humans , Immunotherapy/methods , K562 Cells , Kaplan-Meier Estimate , Lymphocyte Depletion , Mice , Neoplasms/pathology , Neoplasms/therapy , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/metabolism , Protein Binding/immunology , Receptors, IgG/immunology , Receptors, IgG/metabolism , T-Lymphocytes, Regulatory/metabolism
2.
Mol Ther ; 32(6): 1672-1686, 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38549377

ABSTRACT

Stem cell gene therapy and hematopoietic stem cell transplantation (SCT) require conditioning to ablate the recipient's hematopoietic stem cells (HSCs) and create a niche for gene-corrected/donor HSCs. Conventional conditioning agents are non-specific, leading to off-target toxicities and resulting in significant morbidity and mortality. We developed tissue-specific anti-human CD45 antibody-drug conjugates (ADCs), using rat IgG2b anti-human CD45 antibody clones YTH24.5 and YTH54.12, conjugated to cytotoxic pyrrolobenzodiazepine (PBD) dimer payloads with cleavable (SG3249) or non-cleavable (SG3376) linkers. In vitro, these ADCs internalized to lysosomes for drug release, resulting in potent and specific killing of human CD45+ cells. In humanized NSG mice, the ADCs completely ablated human HSCs without toxicity to non-hematopoietic tissues, enabling successful engraftment of gene-modified autologous and allogeneic human HSCs. The ADCs also delayed leukemia onset and improved survival in CD45+ tumor models. These data provide proof of concept that conditioning with anti-human CD45-PBD ADCs allows engraftment of donor/gene-corrected HSCs with minimal toxicity to non-hematopoietic tissues. Our anti-CD45-PBDs or similar agents could potentially shift the paradigm in transplantation medicine that intensive chemo/radiotherapy is required for HSC engraftment after gene therapy and allogeneic SCT. Targeted conditioning both improve the safety and minimize late effects of these procedures, which would greatly increase their applicability.


Subject(s)
Benzodiazepines , Genetic Therapy , Hematopoietic Stem Cell Transplantation , Immunoconjugates , Leukocyte Common Antigens , Animals , Humans , Mice , Immunoconjugates/pharmacology , Leukocyte Common Antigens/metabolism , Genetic Therapy/methods , Hematopoietic Stem Cell Transplantation/methods , Benzodiazepines/pharmacology , Benzodiazepines/chemistry , Hematopoietic Stem Cells/metabolism , Hematopoietic Stem Cells/drug effects , Rats , Transplantation Conditioning/methods , Disease Models, Animal , Antibodies, Monoclonal/pharmacology , Pyrroles
3.
Bioconjug Chem ; 29(2): 486-492, 2018 02 21.
Article in English | MEDLINE | ID: mdl-29384367

ABSTRACT

We describe investigations to expand the scope of next generation maleimide cross-linkers for the construction of homogeneous protein-protein conjugates. Diiodomaleimides are shown to offer the ideal properties of rapid bioconjugation with reduced hydrolysis, allowing the cross-linking of even sterically hindered systems. The optimized linkers are exploited to link human serum albumin to antibody fragments (Fab or scFv) as a prospective half-life extension platform, with retention of antigen binding and robust serum stability. Finally, a triprotein conjugate is formed, by linking scFv antibody fragments targeting carcinoembryonic antigen. This tri-scFv is shown to infer a combination of greater antigen avidity and increased in vivo half-life, representing a promising platform for antibody therapeutic development.


Subject(s)
Cross-Linking Reagents/chemistry , Immunoconjugates/chemistry , Maleimides/chemistry , Serum Albumin, Human/chemistry , Single-Chain Antibodies/chemistry , Humans , Hydrolysis , Immunoglobulin Fab Fragments/chemistry , Models, Molecular
4.
Cancer Immunol Immunother ; 66(11): 1425-1436, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28660319

ABSTRACT

The primary aim of this clinical trial was to determine the feasibility of delivering first-generation CAR T cell therapy to patients with advanced, CEACAM5+ malignancy. Secondary aims were to assess clinical efficacy, immune effector function and optimal dose of CAR T cells. Three cohorts of patients received increasing doses of CEACAM5+-specific CAR T cells after fludarabine pre-conditioning plus systemic IL2 support post T cell infusion. Patients in cohort 4 received increased intensity pre-conditioning (cyclophosphamide and fludarabine), systemic IL2 support and CAR T cells. No objective clinical responses were observed. CAR T cell engraftment in patients within cohort 4 was significantly higher. However, engraftment was short-lived with a rapid decline of systemic CAR T cells within 14 days. Patients in cohort 4 had transient, acute respiratory toxicity which, in combination with lack of prolonged CAR T cell persistence, resulted in the premature closure of the trial. Elevated levels of systemic IFNγ and IL-6 implied that the CEACAM5-specific T cells had undergone immune activation in vivo but only in patients receiving high-intensity pre-conditioning. Expression of CEACAM5 on lung epithelium may have resulted in this transient toxicity. Raised levels of serum cytokines including IL-6 in these patients implicate cytokine release as one of several potential factors exacerbating the observed respiratory toxicity. Whilst improved CAR designs and T cell production methods could improve the systemic persistence and activity, methods to control CAR T 'on-target, off-tissue' toxicity are required to enable a clinical impact of this approach in solid malignancies.


Subject(s)
Carcinoembryonic Antigen/immunology , Immunotherapy, Adoptive/methods , Neoplasms/therapy , Receptors, Antigen, T-Cell/immunology , T-Lymphocytes/immunology , Abdominal Pain/etiology , Adult , Aged , Anemia/etiology , Carcinoembryonic Antigen/genetics , Carcinoembryonic Antigen/metabolism , Cohort Studies , Cyclophosphamide/administration & dosage , Cyclophosphamide/adverse effects , Drug Resistance, Neoplasm , Female , GPI-Linked Proteins/genetics , GPI-Linked Proteins/immunology , GPI-Linked Proteins/metabolism , Gene Expression Regulation, Neoplastic , Humans , Immunotherapy, Adoptive/adverse effects , Interferon-gamma/immunology , Interferon-gamma/metabolism , Interleukin-6/immunology , Interleukin-6/metabolism , Lung/metabolism , Male , Middle Aged , Myeloablative Agonists/adverse effects , Myeloablative Agonists/agonists , Neoplasms/genetics , Neoplasms/immunology , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/metabolism , T-Lymphocytes/metabolism , T-Lymphocytes/transplantation , Treatment Outcome , Vidarabine/administration & dosage , Vidarabine/adverse effects , Vidarabine/analogs & derivatives , Vomiting/etiology
5.
Int J Cancer ; 137(8): 1910-20, 2015 Oct 15.
Article in English | MEDLINE | ID: mdl-25895046

ABSTRACT

Surgery is the cornerstone of oncologic therapy with curative intent. However, identification of tumor cells in the resection margins is difficult, resulting in nonradical resections, increased cancer recurrence and subsequent decreased patient survival. Novel imaging techniques that aid in demarcating tumor margins during surgery are needed. Overexpression of carcinoembryonic antigen (CEA) is found in the majority of gastrointestinal carcinomas, including colorectal and pancreas. We developed ssSM3E/800CW, a novel CEA-targeted near-infrared fluorescent (NIRF) tracer, based on a disulfide-stabilized single-chain antibody fragment (ssScFv), to visualize colorectal and pancreatic tumors in a clinically translatable setting. The applicability of the tracer was tested for cell and tissue binding characteristics and dosing using immunohistochemistry, flow cytometry, cell-based plate assays and orthotopic colorectal (HT-29, well differentiated) and pancreatic (BXPC-3, poorly differentiated) xenogeneic human-mouse models. NIRF signals were visualized using the clinically compatible FLARE™ imaging system. Calculated clinically relevant doses of ssSM3E/800CW selectively accumulated in colorectal and pancreatic tumors/cells, with highest tumor-to-background ratios of 5.1 ± 0.6 at 72 hr postinjection, which proved suitable for intraoperative detection and delineation of tumor boarders and small (residual) tumor nodules in mice, between 8 and 96 hr postinjection. Ex vivo fluorescence imaging and pathologic examination confirmed tumor specificity and the distribution of the tracer. Our results indicate that ssSM3E/800CW shows promise as a diagnostic tool to recognize colorectal and pancreatic cancers for fluorescent-guided surgery applications. If successfully translated clinically, this tracer could help improve the completeness of surgery and thus survival.


Subject(s)
Benzenesulfonates/chemistry , Carcinoembryonic Antigen/metabolism , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/metabolism , Indoles/chemistry , Pancreatic Neoplasms/diagnosis , Pancreatic Neoplasms/metabolism , Single-Chain Antibodies , Animals , Caco-2 Cells , Cell Line, Tumor , Drug Evaluation, Preclinical , Female , HCT116 Cells , HT29 Cells , Humans , Mice , Mice, Nude , Neoplasm Transplantation , Organ Specificity , Single-Chain Antibodies/chemistry , Spectroscopy, Near-Infrared
6.
Bioconjug Chem ; 25(8): 1395-401, 2014 Aug 20.
Article in English | MEDLINE | ID: mdl-25033024

ABSTRACT

We report on a chemical platform to generate site-specific, homogeneous, antibody-antibody conjugates by targeting and bridging disulfide bonds. A bispecific antibody construct was produced in good yield through simple reduction and bridging of antibody fragment disulfide bonds, using a readily synthesized bis-dibromomaleimide cross-linker. Binding activity of antibodies was maintained, and in vitro binding of target antigens was observed. This technology is demonstrated through linking scFv and Fab antibody fragments, showing its potential for the construction of a diverse range of bispecifics.


Subject(s)
Antibody Specificity , Disulfides/chemistry , Single-Chain Antibodies/chemistry , Single-Chain Antibodies/immunology , Protein Multimerization , Protein Structure, Quaternary , Substrate Specificity
7.
Org Biomol Chem ; 12(37): 7261-9, 2014 Oct 07.
Article in English | MEDLINE | ID: mdl-25103319

ABSTRACT

The advent of Adcetris™ and Kadcyla™, two recently FDA-approved antibody-drug conjugates (ADCs), in the clinic has had a major impact on the treatment of lymphoma and breast cancer patients, respectively, worldwide. Despite these successes many new ADCs fail at various stages of development, often due to shortcomings in the methods used for their assembly. To address this problem we have developed next generation maleimides (NGMs), which specifically re-bridge reduced interchain disulfide bonds and allow the efficient conjugation of small molecules to antibodies, without the need for engineering of the target antibody. The method is site-specific and generates near homogeneous products in good yields. Moreover, adjustment of the reaction conditions allows control of the conjugation in terms of stoichiometry (drug-loading) and site selectivity. Using this method we prepared a series of ADCs from trastuzumab and doxorubicin (DOX) with a controlled drug-to-antibody ratio (DAR) of 1, 2, 3 and 4. All of these constructs were fully active by ELISA and had more than 90% of re-bridged disulfide bonds by CE-SDS when compared to clinical grade antibody. Furthermore, digest experiments of the DAR 2 material revealed that almost all of the drug had been targeted to the Fab arms of the antibody. Thus, NGMs offer a flexible and simple platform for the controlled assembly of ADCs from an antibody.


Subject(s)
Antibodies, Monoclonal, Humanized/chemistry , Antibodies/chemistry , Disulfides/chemistry , Doxorubicin/chemistry , Maleimides/chemical synthesis , Maleimides/chemistry , Molecular Structure , Trastuzumab
8.
Cell Death Dis ; 14(2): 104, 2023 02 10.
Article in English | MEDLINE | ID: mdl-36765035

ABSTRACT

Treatment with oncolytic measles vaccines (MV) elicits activation of immune cells, including natural killer (NK) cells. However, we found that MV-activated NK cells show only modest direct cytotoxic activity against tumor cells. To specifically direct NK cells towards tumor cells, we developed oncolytic measles vaccines encoding bispecific killer engagers (MV-BiKE) targeting CD16A on NK cells and carcinoembryonic antigen (CEA) as a model tumor antigen. MV-BiKE are only slightly attenuated compared to parental MV and mediate secretion of functional BiKE from infected tumor cells. We tested MV-BiKE activity in cocultures of colorectal or pancreatic cancer cells with primary human NK cells. MV-BiKE mediate expression of effector cytokines, degranulation and specific anti-tumor cytotoxicity by NK cells. Experiments with patient-derived pancreatic cancer cultures indicate that efficacy of MV-BiKE may vary between individual tumors with differential virus permissiveness. Remarkably, we confirmed MV-BiKE activity in primaryhuman colorectal carcinoma specimens with autochthonous tumor and NK cells.This study provides proof-of-concept for MV-BiKE as a novel immunovirotherapy to harness virus-activated NK cells as anti-tumor effectors.


Subject(s)
Measles , Pancreatic Neoplasms , Vaccines , Humans , Killer Cells, Natural , Antigens, Neoplasm/metabolism , Pancreatic Neoplasms/therapy , Pancreatic Neoplasms/metabolism , Vaccines/metabolism , Measles/metabolism , Cell Line, Tumor
9.
Bioconjug Chem ; 23(8): 1524-33, 2012 Aug 15.
Article in English | MEDLINE | ID: mdl-22681552

ABSTRACT

The potential for protein-engineered biotherapeutics is enormous, but pharmacokinetic modulation is a major challenge. Manipulating pharmacokinetics, biodistribution, and bioavailability of small peptide/protein units such as antibody fragments is a major pharmaceutical ambition, illustrated by the many chemical conjugation and recombinant fusion approaches being developed. We describe a recombinant approach that leads to successful incorporation of polysialic acid, PSA for the first time, onto a therapeutically valuable protein. This was achieved by protein engineering of the PSA carrier domain of NCAM onto single-chain Fv antibody fragments (one directed against noninternalizing carcinoembryonic antigen-CEA and one against internalizing human epidermal growth factor receptor-2-HER2). This created novel polysialylated antibody fragments with desired pharmacokinetics. Production was achieved in human embryonic kidney cells engineered to express human polysialyltransferase, and the recombinant, glycosylated product was successfully fractionated by ion-exchange chromatography. Polysialylation was verified by glycosidase digestion and mass spectrometry, which showed the correct glycan structures and PSA chain length similar to that of native NCAM. Binding was demonstrated by ELISA and surface plasmon resonance and on live cells by flow cytometry and confocal immunofluorescence. Unexpectedly, polysialylation inhibited receptor-mediated endocytosis of the anti-HER2 scFv. Recombinant polysialylation led to an estimated 3-fold increase in hydrodynamic radius, comparable to PEGylation, leading to an almost 30-fold increase in blood half-life and a similar increase in blood exposure. This increase in bioavailability led to a 12-fold increase in tumor uptake by 24 h. In summary, recombinant polysialylation of antibody fragments in our system is a novel and feasible approach applicable for pharmacokinetic modulation, and may have wider applications.


Subject(s)
Protein Engineering/methods , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/therapeutic use , Sialic Acids/metabolism , Single-Chain Antibodies/genetics , Single-Chain Antibodies/therapeutic use , Animals , CD56 Antigen/chemistry , CD56 Antigen/genetics , CD56 Antigen/metabolism , Female , HEK293 Cells , Half-Life , Humans , Hydrodynamics , Mice , Protein Structure, Tertiary , Protein Transport , Rats , Receptor, ErbB-2/immunology , Recombinant Fusion Proteins/immunology , Recombinant Fusion Proteins/pharmacokinetics , Single-Chain Antibodies/immunology , Single-Chain Antibodies/metabolism
10.
J Pathol ; 223(4): 470-81, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21294121

ABSTRACT

Worldwide, approximately 405 000 cases of oral cancer (OSCC) are diagnosed each year, with a rising incidence in many countries. Despite advances in surgery and radiotherapy, which remain the standard treatment options, the mortality rate has remained largely unchanged for decades, with a 5-year survival rate of around 50%. OSCC is a heterogeneous disease, staged currently using the TNM classification, supplemented with pathological information from the primary tumour and loco-regional lymph nodes. Although patients with advanced disease show reduced survival, there is no single pathological or molecular feature that identifies aggressive, early-stage tumours. We retrospectively analysed 282 OSCC patients for disease mortality, related to clinical, pathological, and molecular features based on our previous functional studies [EGFR, αvß6 integrin, smooth muscle actin (SMA), p53, p16, EP4]. We found that the strongest independent risk factor of early OSCC death was a feature of stroma rather than tumour cells. After adjusting for all factors, high stromal SMA expression, indicating myofibroblast transdifferentiation, produced the highest hazard ratio (3.06, 95% CI 1.65-5.66) and likelihood ratio (3.6; detection rate: false positive rate) of any feature examined, and was strongly associated with mortality, regardless of disease stage. Functional assays showed that OSCC cells can modulate myofibroblast transdifferentiation through αvß6-dependent TGF-ß1 activation and that myofibroblasts promote OSCC invasion. Finally, we developed a prognostic model using Cox regression with backward elimination; only SMA expression, metastasis, cohesion, and age were significant. This model was independently validated on a patient subset (detection rate 70%; false positive rate 20%; ROC analysis 77%, p < 0.001). Our study highlights the limited prognostic value of TNM staging and suggests that an SMA-positive, myofibroblastic stroma is the strongest predictor of OSCC mortality. Whether used independently or as part of a prognostic model, SMA identifies a significant group of patients with aggressive tumours, regardless of disease stage.


Subject(s)
Carcinoma, Squamous Cell/pathology , Mouth Neoplasms/pathology , Stromal Cells/pathology , Actins/metabolism , Aged , Biomarkers, Tumor/metabolism , Carcinoma, Squamous Cell/diagnosis , Carcinoma, Squamous Cell/secondary , Carcinoma, Squamous Cell/therapy , Epidemiologic Methods , Female , Humans , Male , Middle Aged , Mouth Neoplasms/diagnosis , Mouth Neoplasms/therapy , Myofibroblasts/physiology , Neoplasm Invasiveness , Neoplasm Proteins/metabolism , Neoplasm Staging , Prognosis , Stromal Cells/metabolism
11.
Int J Cancer ; 122(5): 1155-63, 2008 Mar 01.
Article in English | MEDLINE | ID: mdl-17973256

ABSTRACT

Current photodynamic therapy (PDT) of cancer is limited by inefficiencies involved in specifically targeting photosensitizers to tumors. Although antibodies are being explored as targeting vehicles, they present significant challenges, particularly in terms of pharmacokinetics and drug-coupling. We describe here a novel and effective system to covalently attach multiple photosensitizer molecules (both preclinical, pyropheophorbide-a and clinically approved, verteporfin photosensitizers) to single-chain Fvs. Further, we demonstrate that not only do the resulting photoimmunoconjugates retain photophysical functionality, they are more potent than either free photosensitizer, effectively killing tumor cells in vitro and in vivo. For example, treatment of human breast cancer xenografts with a photoimmunoconjugate comprising an anti-HER-2 scFv linked to 8-10 molecules of pyropheophorbide-a leads to significant tumor regression. These results give an insight into the important features that make scFvs good carriers for PDT drugs and provide proof of concept of our unique approach to targeted photodynamic therapy (tPDT). This promises to significantly improve on current photodynamic therapies for the treatment of cancer.


Subject(s)
Drug Delivery Systems/methods , Immunoglobulin Fragments/administration & dosage , Neoplasms/drug therapy , Photochemotherapy/methods , Photosensitizing Agents/administration & dosage , Amino Acid Sequence , Animals , Antigens, Neoplasm/immunology , Cell Line, Tumor , Humans , Immunoglobulin Fragments/genetics , Mice , Mice, Nude , Molecular Sequence Data , Photosensitizing Agents/pharmacokinetics , Receptor, ErbB-3/immunology , Recombinant Proteins/administration & dosage , Recombinant Proteins/genetics , Recombinant Proteins/pharmacokinetics
12.
Clin Cancer Res ; 12(21): 6509-16, 2006 Nov 01.
Article in English | MEDLINE | ID: mdl-17085666

ABSTRACT

PURPOSE: Antibody-directed enzyme prodrug therapy is a two-stage treatment whereby a tumor-targeted antibody-enzyme complex localizes in tumor for selective conversion of prodrug. The purpose of this study was to establish optimal variables for single administration of MFECP1, a recombinant antibody-enzyme fusion protein of an anti-carcinoembryonic antigen single-chain Fv antibody and the bacterial enzyme carboxypeptidase G2 followed by a bis-iodo phenol mustard prodrug. MFECP1 is manufactured in mannosylated form to facilitate normal tissue elimination. EXPERIMENTAL DESIGN: Pharmacokinetic, biodistribution, and tumor localization studies were used to test the hypothesis that MFECP1 localizes in tumor and clears from normal tissue via the liver. Firstly, safety of MFECP1 and a blood concentration of MFECP1 that would avoid systemic prodrug activation were tested. Secondly, dose escalation of prodrug was done. Thirdly, the dose of MFECP1 and timing of prodrug administration were optimized. RESULTS: MFECP1 was safe and well tolerated, cleared rapidly via the liver, and was less immunogenic than previously used products. Eighty-fold dose escalation from the starting dose of prodrug was carried out before dose-limiting toxicity occurred. Confirmation of the presence of enzyme in tumor and DNA interstrand cross-links indicating prodrug activation were obtained for the optimal dose and time point. A total of 28 of 31 patients was evaluable for response, the best response being a 10% reduction of tumor diameter, and 11 of 28 patients had stable disease. CONCLUSIONS: Optimal conditions for effective therapy were established. A study testing repeat treatment is currently being undertaken.


Subject(s)
Aniline Mustard/analogs & derivatives , Carcinoembryonic Antigen/immunology , Colorectal Neoplasms/drug therapy , Prodrugs/therapeutic use , Recombinant Fusion Proteins/therapeutic use , gamma-Glutamyl Hydrolase/therapeutic use , Aged , Aniline Mustard/blood , Aniline Mustard/pharmacokinetics , Aniline Mustard/therapeutic use , Antibodies, Monoclonal/blood , Antibodies, Monoclonal/therapeutic use , Antineoplastic Agents/blood , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/therapeutic use , Dose-Response Relationship, Drug , Female , History, 16th Century , History, 17th Century , Humans , Imaging, Three-Dimensional , Immunoconjugates/blood , Immunoconjugates/pharmacokinetics , Immunoconjugates/therapeutic use , Male , Prodrugs/adverse effects , Prodrugs/pharmacokinetics , Recombinant Fusion Proteins/blood , Recombinant Fusion Proteins/pharmacokinetics , gamma-Glutamyl Hydrolase/blood , gamma-Glutamyl Hydrolase/pharmacokinetics
13.
Clin Cancer Res ; 11(2 Pt 1): 814-25, 2005 Jan 15.
Article in English | MEDLINE | ID: mdl-15701872

ABSTRACT

PURPOSE: Antibody-directed enzyme prodrug therapy (ADEPT) requires highly selective antibody-mediated delivery of enzyme to tumor. MFE-CP, a multifunctional genetic fusion protein of antibody and enzyme, was designed to achieve this by two mechanisms. First by using a high affinity and high specificity single chain Fv antibody directed to carcinoembryonic antigen. Second by rapid removal of antibody-enzyme from normal tissues by virtue of post-translational mannosylation. The purpose of this paper is to investigate these dual functions in an animal model of pharmacokinetics, pharmacodynamics, toxicity, and efficacy. EXPERIMENTAL DESIGN: MFE-CP was expressed in the yeast Pichia pastoris and purified via an engineered hexahistidine tag. Biodistribution and therapeutic effect of a single ADEPT cycle (1,000 units/kg MFE-CP followed by 70 mg/kg ZD2767P prodrug at 6, 7, and 8 hours) and multiple ADEPT cycles (9-10 cycles within 21-24 days) was studied in established human colon carcinoma xenografts, LS174T, and SW1222. RESULTS: Selective localization of functional enzyme in tumors and rapid clearance from plasma was observed within 6 hours, resulting in tumor to plasma ratios of 1,400:1 and 339:1, respectively for the LS174T and SW1222 models. A single ADEPT cycle produced reproducible tumor growth delay in both models. Multiple ADEPT cycles significantly enhanced the therapeutic effect of a single cycle in the LS174T xenografts (P = 0.001) and produced regressions in the SW1222 xenografts (P = 0.0001), with minimal toxicity. CONCLUSIONS: MFE-CP fusion protein, in combination with ZD2767P, provides a new and successful ADEPT system, which offers the potential for multiple cycles and antitumor efficacy. These results provide a basis for the next stage in clinical development of ADEPT.


Subject(s)
Carcinoembryonic Antigen/immunology , Colonic Neoplasms/therapy , Mannose/metabolism , Nitrogen Mustard Compounds/therapeutic use , Prodrugs/therapeutic use , Recombinant Fusion Proteins/therapeutic use , gamma-Glutamyl Hydrolase/metabolism , Animals , Colonic Neoplasms/diagnostic imaging , Colonic Neoplasms/metabolism , Female , Humans , Immunoglobulin Fragments/genetics , Immunoglobulin Fragments/metabolism , Metabolic Clearance Rate , Mice , Mice, Nude , Nitrogen Mustard Compounds/pharmacokinetics , Pichia/metabolism , Prodrugs/pharmacokinetics , Protein Engineering , Protein Processing, Post-Translational , Radionuclide Imaging , Recombinant Fusion Proteins/pharmacokinetics , Tissue Distribution , Transplantation, Heterologous , gamma-Glutamyl Hydrolase/genetics
14.
MAbs ; 8(8): 1425-1434, 2016.
Article in English | MEDLINE | ID: mdl-27557809

ABSTRACT

Antibody Engineering & Therapeutics, the largest meeting devoted to antibody science and technology and the annual meeting of The Antibody Society, will be held in San Diego, CA on December 11-15, 2016. Each of 14 sessions will include six presentations by leading industry and academic experts. In this meeting preview, the session chairs discuss the relevance of their topics to current and future antibody therapeutics development. Session topics include bispecifics and designer polyclonal antibodies; antibodies for neurodegenerative diseases; the interface between passive and active immunotherapy; antibodies for non-cancer indications; novel antibody display, selection and screening technologies; novel checkpoint modulators / immuno-oncology; engineering antibodies for T-cell therapy; novel engineering strategies to enhance antibody functions; and the biological Impact of Fc receptor engagement. The meeting will open with keynote speakers Dennis R. Burton (The Scripps Research Institute), who will review progress toward a neutralizing antibody-based HIV vaccine; Olivera J. Finn, (University of Pittsburgh School of Medicine), who will discuss prophylactic cancer vaccines as a source of therapeutic antibodies; and Paul Richardson (Dana-Farber Cancer Institute), who will provide a clinical update on daratumumab for multiple myeloma. In a featured presentation, a representative of the World Health Organization's INN expert group will provide a perspective on antibody naming. "Antibodies to watch in 2017" and progress on The Antibody Society's 2016 initiatives will be presented during the Society's special session. In addition, two pre-conference workshops covering ways to accelerate antibody drugs to the clinic and the applications of next-generation sequencing in antibody discovery and engineering will be held on Sunday December 11, 2016.


Subject(s)
Antibodies , Protein Engineering/methods , Animals , Antibodies/therapeutic use , Humans
15.
MAbs ; 8(1): 1-9, 2016.
Article in English | MEDLINE | ID: mdl-26716992

ABSTRACT

An important step in drug development is the assignment of an International Nonproprietary Name (INN) by the World Health Organization (WHO) that provides healthcare professionals with a unique and universally available designated name to identify each pharmaceutical substance. Monoclonal antibody INNs comprise a -mab suffix preceded by a substem indicating the antibody type, e.g., chimeric (-xi-), humanized (-zu-), or human (-u-). The WHO publishes INN definitions that specify how new monoclonal antibody therapeutics are categorized and adapts the definitions to new technologies. However, rapid progress in antibody technologies has blurred the boundaries between existing antibody categories and created a burgeoning array of new antibody formats. Thus, revising the INN system for antibodies is akin to aiming for a rapidly moving target. The WHO recently revised INN definitions for antibodies now to be based on amino acid sequence identity. These new definitions, however, are critically flawed as they are ambiguous and go against decades of scientific literature. A key concern is the imposition of an arbitrary threshold for identity against human germline antibody variable region sequences. This leads to inconsistent classification of somatically mutated human antibodies, humanized antibodies as well as antibodies derived from semi-synthetic/synthetic libraries and transgenic animals. Such sequence-based classification implies clear functional distinction between categories (e.g., immunogenicity). However, there is no scientific evidence to support this. Dialog between the WHO INN Expert Group and key stakeholders is needed to develop a new INN system for antibodies and to avoid confusion and miscommunication between researchers and clinicians prescribing antibodies.


Subject(s)
Antibodies , Animals , Humans , Terminology as Topic
16.
J Mol Biol ; 320(1): 107-27, 2002 Jun 28.
Article in English | MEDLINE | ID: mdl-12079338

ABSTRACT

MFE-23 is a single chain Fv (scFv) antibody molecule used to target colorectal cancer through its high affinity for the tumour marker carcinoembryonic antigen (CEA). ScFv molecules are formed from peptide-linked antibody V(H) and V(L) domains, and many of these form dimers. Our recent crystal structure for MFE-23 showed that this formed an unusual symmetric back-to-back association of two monomers that is consistent with a domain-swapped diabody structure. Neutron scattering and modelling fits showed that MFE-23 existed as compact V(H)-V(L)-linked monomers at therapeutically relevant concentrations below 1 mg/ml. Size-exclusion gel chromatography showed that the monomeric and dimeric forms of MFE-23 could be separated, and that the proportions of these two forms depended on the starting MFE-23 concentration. Sedimentation equilibrium experiments by analytical ultracentrifugation at nine concentrations of MFE-23 indicated a reversible monomer-dimer self-association equilibrium with an association constant of 1.9x10(3)-2.2x10(3) M(-1). Sedimentation velocity experiments using the time derivative g(s(*)) method showed that MFE-23-His has a concentration-dependent weight average sedimentation coefficient that increased from 1.8 S for the monomer to about 3-6 S for the dimer. Both values agreed with those calculated from the MFE-23 crystal structure. In relation to the thermal stability of MFE-23, denaturation experiments by (1)H NMR and FT-IR spectroscopy showed that the molecule is stable up to 47 degrees C, after which denaturation was irreversible. MFE-23 dimerisation is discussed in terms of a new model for diabody structures, in which the V(H) and V(L) domains in the monomer are able to dissociate and reassociate to form a dimer, or diabody, but in which symmetric back-to-back contacts between the two monomers are formed. This dimerisation in solution is attributed to the complementary nature of the C-terminal surface of the MFE-23 monomer. Crystal structures for seven other scFv molecules have shown that, while the contact residues for symmetric back-to-back dimer formation in MFE-23 are not fully conserved, in principle, back-to-back contacts can be formed in these too. This offers possibilities for the creation of other forms of scFv molecules.


Subject(s)
Antineoplastic Agents/metabolism , Immunoglobulin Fragments/metabolism , Amino Acid Sequence , Antineoplastic Agents/chemistry , Dimerization , Humans , Immunoglobulin Fragments/chemistry , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Sequence Data , Neutrons , Protein Structure, Quaternary , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Spectroscopy, Fourier Transform Infrared , Temperature , Ultracentrifugation
17.
Nat Commun ; 6: 6645, 2015 Mar 31.
Article in English | MEDLINE | ID: mdl-25824906

ABSTRACT

Although recent methods for the engineering of antibody-drug conjugates (ADCs) have gone some way to addressing the challenging issues of ADC construction, significant hurdles still remain. There is clear demand for the construction of novel ADC platforms that offer greater stability, homogeneity and flexibility. Here we describe a significant step towards a platform for next-generation antibody-based therapeutics by providing constructs that combine site-specific modification, exceptional versatility and high stability, with retention of antibody binding and structure post-modification. The relevance of the work in a biological context is also demonstrated in a cytotoxicity assay and a cell internalization study with HER2-positive and -negative breast cancer cell lines.


Subject(s)
Antibodies/chemistry , Antineoplastic Agents/chemistry , Breast Neoplasms/drug therapy , Drug Delivery Systems/methods , Immunoconjugates/chemistry , Trastuzumab/chemistry , Antibodies/therapeutic use , Antineoplastic Agents/administration & dosage , Breast Neoplasms/metabolism , Cell Line, Tumor , Chromatography, Liquid , Click Chemistry , Electrophoresis, Polyacrylamide Gel , Humans , Immunoconjugates/therapeutic use , Mass Spectrometry , Microscopy, Confocal , Photoelectron Spectroscopy , Receptor, ErbB-2/metabolism , Trastuzumab/administration & dosage
18.
MAbs ; 7(6): 981-8, 2015.
Article in English | MEDLINE | ID: mdl-26421752

ABSTRACT

Antibody Engineering & Therapeutics, the annual meeting of The Antibody Society, will be held in San Diego, CA in early December 2015. In this meeting preview, the chairs provide their thoughts on the importance of their session topics, which include antibody effector functions, reproducibility of research and diagnostic antibodies, new developments in antibody-drug conjugates (ADCs), preclinical and clinical ADC data, new technologies and applications for bispecific antibodies, antibody therapeutics for non-cancer and orphan indications, antibodies to harness the cellular immune system, overcoming resistance to clinical immunotherapy, and building comprehensive IGVH-gene repertoires through discovering, confirming and cataloging new germline IGVH genes. The Antibody Society's special session will focus on "Antibodies to watch" in 2016, which are a subset of the nearly 50 antibodies currently in Phase 3 clinical studies. Featuring over 100 speakers in total, the meeting will commence with keynote presentations by Erica Ollmann Saphire (The Scripps Research Institute), Wayne A. Marasco (Dana-Farber Cancer Institute/Harvard Medical School), Joe W. Gray (Oregon Health & Science University), and Anna M. Wu (University of California Los Angeles), and it will conclude with workshops on the promise and challenges of using next-generation sequencing for antibody discovery and engineering from synthetic and in vivo libraries and on computational antibody design.


Subject(s)
Antibodies, Bispecific/immunology , Antibodies, Monoclonal/immunology , Immunoconjugates/immunology , Protein Engineering/methods , Antibodies, Monoclonal/therapeutic use , Drug Discovery/methods , Humans , Immunoconjugates/therapeutic use , Immunoglobulin Fc Fragments/immunology , Immunoglobulin Fc Fragments/therapeutic use , Immunotherapy/methods , Translational Research, Biomedical/methods
19.
Chem Commun (Camb) ; 50(54): 7139-42, 2014 Jul 11.
Article in English | MEDLINE | ID: mdl-24853662

ABSTRACT

Tuning the properties of maleimide reagents holds significant promise in expanding the toolbox of available methods for bioconjugation. Herein we describe aryloxymaleimides which represent 'next generation maleimides' of attenuated reactivity, and demonstrate their ability to enable new methods for protein modification at disulfide bonds.


Subject(s)
Cysteine/chemistry , Disulfides/chemistry , Maleimides/chemistry , GRB2 Adaptor Protein/chemistry , Maleimides/chemical synthesis , Somatostatin/chemistry
20.
MAbs ; 6(5): 1115-23, 2014.
Article in English | MEDLINE | ID: mdl-25517297

ABSTRACT

The 25th anniversary of the Antibody Engineering & Therapeutics Conference, the Annual Meeting of The Antibody Society, will be held in Huntington Beach, CA, December 7-11, 2014. Organized by IBC Life Sciences, the event will celebrate past successes, educate participants on current activities and offer a vision of future progress in the field. Keynote addresses will be given by academic and industry experts Douglas Lauffenburger (Massachusetts Institute of Technology), Ira Pastan (National Cancer Institute), James Wells (University of California, San Francisco), Ian Tomlinson (GlaxoSmithKline) and Anthony Rees (Rees Consulting AB and Emeritus Professor, University of Bath). These speakers will provide updates of their work, placed in the context of the substantial growth of the industry over the past 25 years.


Subject(s)
Antibodies/immunology , Antibodies/therapeutic use , Protein Engineering/methods , Antibodies/genetics , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Humans
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