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EP-4741421-A1 - FAB-ARM EXCHANGE-PREVENTING FC VARIANTS FROM WHICH EFFECTOR FUNCTIONS ARE REMOVED

EP4741421A1EP 4741421 A1EP4741421 A1EP 4741421A1EP-4741421-A1

Abstract

The present disclosure relates to Fab-arm exchange-preventing Fc variants having reduced effector functions due to the removal of binding affinity to FcyRs and C1q. Human antibody Fc domain variants of the present disclosure are novel variants different from conventional Fab-arm exchange-preventing variants and can overcome the Fab-arm exchange phenomenon, which is a disadvantage of IgG4, while not binding to all human FcyRs and C1q and not binding to mouse and monkey Fc7Rs, and have excellent blood half-life and thermal stability, and thus can be used for the prevention of immune cell/normal cell death (toxicity) caused by an antibody Fc region of a therapeutic antibody or Fc-fusion protein drug.

Inventors

  • JUNG, Sang-Taek
  • KIM, SU-YEON
  • JO, Mi-Gyeong
  • KYUNG, Mun-Su
  • KO, Woo-Hyung

Assignees

  • Korea University Research and Business Foundation

Dates

Publication Date
20260513
Application Date
20241101

Claims (20)

  1. A human antibody Fc domain variant, wherein amino acids at any one or more positions selected from the group consisting of amino acids at positions 231, 232, 234, and 235 numbered according to a Kabat numbering system in a wild-type human antibody Fc domain are substituted with sequences different from wild-type amino acids.
  2. The human antibody Fc domain variant of claim 1, wherein the human antibody Fc domain variant includes any one or more amino acid substitutions selected from the group consisting of A231C, P232C, F234C, and L235C.
  3. The human antibody Fc domain variant of claim 1, wherein the human antibody is IgG4.
  4. The human antibody Fc domain variant of claim 1, wherein binding affinity to Fc gamma receptors (FcγRs) is reduced compared to the wild-type human antibody Fc domain.
  5. The human antibody Fc domain variant of claim 4, wherein the human antibody Fc domain variant is human, mouse or monkey Fc gamma receptors (FcyRs).
  6. The human antibody Fc domain variant of claim 1, wherein binding affinity to C1q is reduced compared to the wild-type human antibody Fc domain.
  7. The human antibody Fc domain variant of claim 1, wherein effector functions are reduced compared to the wild-type human antibody Fc domain.
  8. The human antibody Fc domain variant of claim 7, wherein the effector function is an Fc-mediated effector function selected from C1q-binding, complement activation, complement dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), Fc-receptor binding including Fc-gamma receptor binding, protein A-binding, protein G-binding, antibody-dependent cell-mediated phagocytosis (ADCP), complement dependent cell-mediated cytotoxicity (CDCC), complement-enhanced cytotoxicity, opsonization, Fc-containing polypeptide internalization, target downmodulation, ADC uptake, induction of apoptosis, cell death, cell cycle arrest, and any combination thereof.
  9. The human antibody Fc domain variant of claim 1, wherein thermal stability is increased compared to the wild-type human antibody Fc domain.
  10. The human antibody Fc domain variant of claim 1, wherein in vivo half-life is increased compared to the wild-type human antibody Fc domain.
  11. An antibody or immunologically active fragment thereof, comprising the human antibody Fc domain variant of claim 1.
  12. The antibody or immunologically active fragment thereof of claim 11, wherein binding affinity to Fc gamma receptors (FcγRs) is reduced compared to a wild-type human antibody.
  13. The antibody or immunologically active fragment thereof of claim 11, wherein binding affinity to C1q is reduced compared to the wild-type human antibody.
  14. The antibody or immunologically active fragment thereof of claim 11, wherein effector functions are reduced compared to the wild-type human antibody.
  15. The antibody or immunologically active fragment thereof of claim 11, wherein the antibody is a polyclonal antibody, a monoclonal antibody, a minibody, a domain antibody, a bispecific antibody, an IgG-like bispecific antibody, a bispecific immune cell engager, an antibody mimetic, a chimeric antibody, an antibody conjugate, a human antibody, a humanized antibody, a bivalent antibody or a bispecific molecule.
  16. A nucleic acid molecule encoding the human antibody Fc domain variant of claim 1, or the antibody or immunologically active fragment thereof of claim 11.
  17. An Fc-fusion protein in which the human antibody Fc domain variant of claim 1 is fused with a protein therapeutic agent.
  18. The Fc-fusion protein of claim 17, wherein the protein therapeutic agent is a T-cell modulatory polypeptide (TMP), an immune checkpoint protein or immune effector cell-specific targeting molecule, an immune checkpoint inhibitor antibody, a bispecific immune cell engaging bispecific antibody, an agonist antibody, or an antagonist antibody.
  19. The Fc-fusion protein of claim 18, wherein the immune checkpoint protein is CD27, CD28, CD40, CD122, CD96, CD73, CD47, OX40, GITR, CSF1R, JAK, PI3K delta, PI3K gamma, TAM, arginase, CD137, ICOS, A2AR, B7-H3, B7-H4, BTLA, CTLA-4, LAG3, TIM3, VISTA, CD96, TIGIT, CD122, PD-1, PD-L1, or PD-L2.
  20. The Fc-fusion protein of claim 18, wherein the immune checkpoint inhibitor antibody is atezolizumab, avelumab, durvalumab, ipilimumab, IPH4102, IPH43, IPH33, lirimumab, monalizumab, nivolumab, pembrolizumab, and derivatives or functional equivalents thereof.

Description

[Technical Field] The present disclosure relates to Fab-arm exchange-preventing Fc variants having reduced effector functions due to the removal of binding affinity to FcyRs and C1q. [Background Art] Protein therapeutic agents have been widely used in clinical trials by rapidly replacing non-specific low molecular compound therapeutic agents due to very high specificity for disease targets and low side effects and toxicity. Among protein therapeutic agents which have been currently used in clinical trials, antibody therapeutics and Fc-fusion protein therapeutics fused with antibody Fc regions make up the largest part. Therapeutic antibodies are considered as one of the most effective cancer therapies by exhibiting very high target specificity compared to conventional low molecular drugs, and having not only low biotoxicity and few side effects, but also an excellent blood half-life of about 3 weeks. In fact, large pharmaceutical companies and research institutes around the world are accelerating the research and development of therapeutic antibodies that specifically bind to cancer cells, including cancer-causing factors, to effectively remove the cancer cells. Companies for developing therapeutic antibody drugs mainly consist of pharmaceutical companies, such as Roche, Amgen, Johnson & Johnson, Abbott, and BMS. Particularly, Roche includes representative products of Herceptin, Avastin, Rituxan, and the like for anticancer treatment, and not only produces large profits, achieving sales of approximately $19.5 billion in the global market in 2012 with these three therapeutic antibodies, but also leads the global antibody drug market. Johnson & Johnson, which developed Remicade, is also growing rapidly in the global antibody market due to increased sales, and pharmaceutical companies such as Abbott and BMS are also known to have many therapeutic antibodies in the final stages of development. As a result, in the global pharmaceutical market, where low molecular drugs had been dominant, the low molecular drugs have been rapidly replaced with biopharmaceuticals including therapeutic antibodies that are specific to disease targets and have low side effects. The antibody provides a link between the humoral and cellular immune systems, and a Fab region of the antibody recognizes an antigen, whereas an Fc domain part binds to a receptor (Fc receptor or FcR) for an antibody (immunoglobulin) on a cell that is differentially expressed by all immune competent cells and has a different mechanism depending on a type of FcγR expressed on the surface of the binding immune cell. An Fc receptor binding site on the Fc region of the antibody binds to the Fc receptor (FcR) on the cell, and the antibody binds to the Fc receptor on the cell surface through the Fc region to trigger a variety of important biological responses, including phagocy and destruction of antibody-coated particles, removal of immune complexes, lysis of antibody-coated target cells by killing cells (antibody-dependent cell-mediated cytotoxicity, or ADCC), release of inflammatory mediators, placental transfer and control of immunoglobulin production (Deo, Y.M. et al., Immunol. Today 18(3):127-135 (1997)). As such, the Fc domain plays a critical role in the recruitment of immune cells, and antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP). In particular, the ADCC and ADCP functions, which are effector functions of the antibody, depend on interaction with Fc receptors present on the surfaces of many cells. Human Fc receptors are classified into five types, and the type of immune cell to be recruited is determined depending on which Fc receptor the antibody binds to. For example, the Fc domain of the antibody is responsible for the major therapeutic effects of therapeutic antibodies by inducing the effector functions of ADCC by binding to FcγRIIIa, ADCP by binding to FcγRI or FcγRIIa, and complement dependent cytotoxicity (CDC) by binding to C1q to have toxicity as the target antigen binding to the Fab region. However, in the therapeutic context, the effector functions of the antibody are often not preferred and may cause a safety problem and unwanted side effects by activating host immune defenses. For example, some therapeutic antibodies, such as immune checkpoint inhibitors that bind to immune cells and bispecific immune cell engagers, had a problem of side effects in which the immune mechanism is shown in the targeted immune cells to destroy the immune cells. Immune checkpoint inhibitors that target immune checkpoint proteins expressed on the surface of immune cells such as T cells have the disadvantage of lowering the original effects of antibodies by causing the side effects of destroying immune cells required to remove cancer cells by activating the immune responses due to an Fc-mediated immune mechanism. In addition, it has been reported that an immune cell activation inhibitory receptor (FcyRIIb)