Antibody-based cancer therapy Goydel, Rebecca S; Rader, Christoph
Oncogene,
05/2021, Letnik:
40, Številka:
21
Journal Article
Recenzirano
Odprti dostop
Over the past 25 years, antibody therapeutics have emerged as clinically and commercially successful pharmaceuticals, rapidly approaching 100 Food and Drug Administration approvals with combined ...annual global sales exceeding $100 billion. Nearly half of the marketed antibody therapeutics are used in oncology. These antibody-based cancer therapies can be broken down into three categories based on their different mechanisms of action, i.e., (i) natural properties, (ii) engagement of cytotoxic T cells, and (iii) delivery of cytotoxic payloads. Both natural and engineered properties of the antibody molecule are founded on its highly stable and modular architecture. In this review we provide an overview and outlook of the rapidly evolving landscape of antibody-based cancer therapy.
Current strategies to produce homogeneous antibody-drug conjugates (ADCs) rely on mutations or inefficient conjugation chemistries. Here we present a strategy to produce site-specific ADCs using a ...highly reactive natural buried lysine embedded in a dual variable domain (DVD) format. This approach is mutation free and drug conjugation proceeds rapidly at neutral pH in a single step without removing any charges. The conjugation chemistry is highly robust, enabling the use of crude DVD for ADC preparation. In addition, this strategy affords the ability to precisely monitor the efficiency of drug conjugation with a catalytic assay. ADCs targeting HER2 were prepared and demonstrated to be highly potent and specific in vitro and in vivo. Furthermore, the modular DVD platform was used to prepare potent and specific ADCs targeting CD138 and CD79B, two clinically established targets overexpressed in multiple myeloma and non-Hodgkin lymphoma, respectively.
Antibodies are widely used as cancer therapeutics, but their current use is limited by the low number of antigens restricted to cancer cells. A receptor tyrosine kinase, receptor tyrosine kinase-like ...orphan receptor 2 (ROR2), is normally expressed only during embryogenesis and is tightly down-regulated in postnatal healthy tissues. However, it is up-regulated in a diverse set of hematologic and solid malignancies, thus ROR2 represents a candidate antigen for antibody-based cancer therapy. Here we describe the affinity maturation and humanization of a rabbit mAb that binds human and mouse ROR2 but not human ROR1 or other human cell-surface antigens. Co-crystallization of the parental rabbit mAb in complex with the human ROR2 kringle domain (hROR2-Kr) guided affinity maturation by heavy-chain complementarity-determining region 3 (HCDR3)-focused mutagenesis and selection. The affinity-matured rabbit mAb was then humanized by complementarity-determining region (CDR) grafting and framework fine tuning and again co-crystallized with hROR2-Kr. We show that the affinity-matured and humanized mAb retains strong affinity and specificity to ROR2 and, following conversion to a T cell–engaging bispecific antibody, has potent cytotoxicity toward ROR2-expressing cells. We anticipate that this humanized affinity-matured mAb will find application for antibody-based cancer therapy of ROR2-expressing neoplasms.
Metastatic medullary thyroid cancer (MTC) is a rare but often aggressive thyroid malignancy with a 5-year survival rate of less than 40% and few effective therapeutic options. Adoptive T cell ...immunotherapy using chimeric antigen receptor (CAR)-modified T cells (CAR Ts) is showing encouraging results in the treatment of cancer, but development is challenged by the availability of suitable target antigens. We identified glial-derived neurotrophic factor (GDNF) family receptor alpha 4 (GFRα4) as a putative antigen target for CAR-based therapy of MTC. We show that GFRα4 is highly expressed in MTC, in parafollicular cells within the thyroid from which MTC originates, and in normal thymus. We isolated two single-chain variable fragments (scFvs) targeting GFRα4 isoforms a and b by antibody phage display. CARs bearing the CD3ζ and the CD137 costimulatory domains were constructed using these GFRα4-specific scFvs. GFRα4-specific CAR Ts trigger antigen-dependent cytotoxicity and cytokine production in vitro, and they are able to eliminate tumors derived from the MTC TT cell line in an immunodeficient mouse xenograft model of MTC. These data demonstrate the feasibility of targeting GFRα4 by CAR T and support this antigen as a promising target for adoptive T cell immunotherapy and other antibody-based therapies for MTC.
Display omitted
Metastatic medullary thyroid carcinoma (MTC) is a rare but aggressive malignancy with no curative options. By sequencing mRNA from a patient’s tumor, Siegel and colleagues identified and characterized GFRα4 as a promising tumor target antigen and demonstrated that CAR T immunotherapy targeting this antigen controlled MTC in tumor xenograft models.
Antibody therapies traditionally target well defined cancer cell surface antigens to avoid or limit on-target off-tissue toxicity. This has limited the number of suitable targets to just a handful ...out of the more than 5,000 cell surface proteins. This thesis describes the development of a strategy to utilize widely expressed proteins as cancer targets in a new T-cell engaging bispecific antibody format designed to mitigate on-target off-tissue effects. The format is conditionally active in the tumor microenvironment by utilization of tightly controlled enzymes such as matriptase. A proof-of-concept study utilizes the widely studied ubiquitous cancer target EGFR, but in the future can be easily expanded to other more or less ubiquitously expressed cancer targets such as ROR2. Suitability of ROR2 as a new cancer target for T-cell engaging bispecific antibodies and the development and characterization of a humanized ROR2-targeting antibody of broad therapeutic utility is described in the first part of this thesis.
Abstract
Autoimmune diseases are triggered by a critical break in peripheral tolerance, thereby allowing the immune system to target and destroy host tissues. Tolerance mechanisms, such as inhibitory ...receptor (IRs) on T cells, can greatly influence autoimmune disease progression and outcomes, representing an opportunity for therapeutic intervention. Indeed, evidence in both animal models and patients suggests that IRs play a major role in limiting autoimmunity. Immunotherapies targeting IRs have revolutionized the treatment of many cancers and provided evidence that IR modulating therapeutics can significantly impact patient outcomes. However importantly, analogous IR-targeted autoimmune therapeutics have just begun to be tested.
Despite interest, IR agonist antibodies have proven difficult to generate. Optimal agonist antibodies require IR superclustering, which is not efficiently induced by Fc-null antibodies. Successful agonists will likely rely on simultaneous Fc (constant region) tethering on antigen presenting cells (APC), thereby allowing efficient IR superclustering and downstream signaling. Current agonistic antibodies targeting IRs contain an IgG1 wild-type Fc, which by binding both activating and inhibitory Fc receptors can trigger unwanted production of inflammatory cytokines by APCs. Here we show that antibodies binding selectively FcγRIIb, support superior agonism compared to IgG1 wild-type antibodies and mitigate potential liability of current IR agonists under clinical investigation. Indeed, dual targeting of the APC and T cells shows promising pre-clinical results and will be used to create novel IR agonists.
Abstract
Biologics targeting multiple pathways and/or multiple cell types simultaneously have the potential to restore normal immune homeostasis. Inhibitory checkpoint receptor agonism by antibodies ...benefits from higher order clustering for strong activation, which can be achieved by antibody Fc binding to Fc gamma receptors (FcγRs). However, many of the current agonist antibodies non discriminately bind activating FcγRs. This has the potential to trigger inflammatory cytokines by antigen presenting cells (APCs) or cause antibody dependent cellular cytotoxicity (ADCC).
Clustering by Fc binding to the inhibitory Fc receptor, FcγRIIb has the potential to provide superior clustering by avoiding inflammatory cytokine responses and limiting APC activation. However, FcγRIIb is 93% homologous to the activating receptor FcγRIIa, and designing molecules that specifically bind FcγRIIb presents a challenge that our IMPACT platform can address. Using integrated machine learning, structural biology and traditional antibody campaigns, we have identified selective FcγRIIb binding molecules, and characterized their potential for IMPACTing immune-mediated diseases.
PDF
