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EP-4741426-A1 - COMPLEX OF ANTIBODY AND IL-2 AND USE THEREOF

EP4741426A1EP 4741426 A1EP4741426 A1EP 4741426A1EP-4741426-A1

Abstract

The present invention relates to the technical field of antibodies, and in particular, to a complex of an antibody and IL-2 and a use thereof. Provided is a complex of an antibody and IL-2, comprising: an immune checkpoint antibody and an IL15Rα receptor domain that are covalently linked, and an IL-2/15 chimera (S-unit molecule) or a variant thereof that is non-covalently compounded with the IL15Rα receptor domain. By means of design, IL-2 molecules are gradually dissociated from the complex to achieve a short half-life period, and the immune checkpoint antibody achieves a long half-life period due to the fact that an Fc domain is recycled by binding to FcRn. Therefore, the half-life period and the administration dosage of the two molecules can be matched with each other.

Inventors

  • GAO, XIANG
  • WANG, GUOYONG
  • WEI, Tingting
  • TAN, WEI
  • ZHANG, TING
  • ZHU, XIAOTING
  • DU, Wenyu
  • ZHANG, JIANJUN
  • ZHANG, WEI

Assignees

  • Leto Laboratories Co., Ltd

Dates

Publication Date
20260513
Application Date
20240705

Claims (20)

  1. A complex of an antibody and IL-2, comprising: an immune checkpoint antibody and an IL15Rα receptor domain that are covalently linked, and an IL-2/15 chimera or a variant thereof that is non-covalently complexed with the IL15Rα receptor domain.
  2. The complex according to claim 1, wherein the IL-2/15 chimera or the variant thereof comprises one or more of: substituting loop M (SEQ ID NO: 1) or a variant thereof in a region that mediates binding of an IL-2 molecule to IL2Rα with loop m (SEQ ID NO: 8) or a variant thereof in a region that mediates binding of an IL-15 molecule to IL15Rα; substituting helix B (SEQ ID NO: 2) or a variant thereof with helix b (SEQ ID NO: 9) or a variant thereof in a region that mediates binding of an IL-15 molecule to IL15Rα; substituting loop X (SEQ ID NO: 3) or a variant thereof in a region that mediates binding of an IL-2 molecule to IL2Rα with loop x (SEQ ID NO: 10) or a variant thereof in a region that mediates binding of an IL-15 molecule to IL15Rα; substituting helix C (SEQ ID NO: 4) or a variant thereof with helix c (SEQ ID NO: 11) or a variant thereof in a region that mediates binding of an IL-15 molecule to IL15Rα; or substituting loop N (SEQ ID NO: 5) or a variant thereof in a region that mediates binding of an IL-2 molecule to IL2Rα with loop n (SEQ ID NO: 12) or a variant thereof in a region that mediates binding of an IL-15 molecule to IL15Rα; and optionally, performing an amino acid replacement in a helix D region of the IL-2 molecule, wherein the replaced amino acid is capable of forming an aromatic ring interaction with phenylalanine (F) at position 43 in helix b to stabilize the hydrophobic core, wherein the position of the amino acid is determined based on an amino acid sequence of a natural IL-15 molecule according to the EU index of KABAT numbering; helix D comprises a sequence set forth in SEQ ID NO. 6; and the IL-2 wild-type molecule has a sequence set forth in SEQ ID NO: 7.
  3. The complex according to claim 2, wherein the IL-2/15 chimera or the variant thereof comprises a sequence set forth in SEQ ID NO. 14.
  4. The complex according to claim 2, wherein the IL-2/15 chimera or the variant thereof is a variant sequence comprising one or more amino acid substitutions of N77D, E76Q, I80T, and/or L81T; and/or a variant having one, two, or three amino acid deletions at the C-terminus.
  5. The complex according to claim 4, wherein the IL-2/15 chimera or the variant thereof has a sequence set forth in SEQ ID NOs. 15-18 or 23-25.
  6. The complex according to claim 1, wherein the IL15Rα receptor domain comprises a sushi domain or a variant thereof.
  7. The complex according to claim 6, wherein the sushi domain or the variant thereof comprises a sequence set forth in SEQ ID NO. 19.
  8. The complex according to claim 1, wherein the IL15Rα receptor domain is linked to the C-terminus of the heavy chain of the immune checkpoint antibody.
  9. The complex according to claim 8, wherein the immune checkpoint antibody and the IL15Rα receptor domain are covalently linked by means of fusion.
  10. The complex according to claim 9, wherein the fusion is achieved via a polypeptide linker protein.
  11. The complex according to claim 10, wherein the polypeptide linking protein is (G 4 S) n , wherein n is an integer.
  12. The complex according to any one of claims 1 to 11, wherein the immune checkpoint antibody is an antibody targeting a programmed death receptor and a ligand thereof.
  13. The complex according to claim 12, wherein the immune checkpoint antibody is a PD-1 antibody.
  14. The complex according to claim 13, wherein the PD-1 antibody light chain LC is set forth in SEQ ID NO: 20.
  15. The complex according to claim 13, wherein the fusion protein of the PD-1 heavy chain HC and the IL15Rα receptor domain has a sequence set forth in SEQ ID NO: 21.
  16. A nucleic acid molecule, encoding the complex according to any one of claims 1-15.
  17. A nucleic acid molecule combination, comprising a nucleic acid molecule encoding the immune checkpoint antibody and the IL15Rα receptor domain that are covalently linked according to any one of claims 1-15; and a nucleic acid molecule encoding the IL-2/15 chimera according to any one of claims 1-15.
  18. A vector, comprising the nucleic acid molecule according to claim 16 or the nucleic acid molecule combination according to claim 17.
  19. A host cell, comprising the complex according to any one of claims 1-15, the nucleic acid molecule according to claim 16, the nucleic acid molecule combination according to claim 17, or the vector according to claim 18.
  20. A pharmaceutical composition, comprising: the complex according to any one of claims 1-15, the nucleic acid molecule according to claim 16, the nucleic acid molecule combination according to claim 17, the vector according to claim 18, or the host cell according to claim 19, and a pharmaceutically acceptable excipient.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to the prior application with the Patent Application No. 202310832340X and entitled "COMPLEX OF ANTIBODY AND IL-2 AND USE THEREOF" filed with the China National Intellectual Property Administration on July 07, 2023, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to the technical field of antibodies, and in particular to a complex of an antibody and IL-2 and use thereof. BACKGROUND Cancer is a disease that seriously compromises the human health and life expectancy, which is characterized by the overgrowth of malignant tumor cells and may cause a variety of complications. Since entering the 21st century, tumor immunotherapy represented by PD-1/PD-L1 has revolutionized tumor immunotherapy and achieved great success. The development of new tumor immunotherapy targets and combination administration regimens has become one of the biggest hotspots in new drug research and development in China and even the world. However, with the accumulation of more clinical data on a series of PD-1/PD-L1 antibodies such as Keytruda and Opdivo, the limitations of PD-1/PD-L1 antibodies in the field of solid tumor treatment have become increasingly apparent. Cytokines, as naturally occurring immune cell agonists, exhibit highly promising potential in enhancing the overall immune system and antagonizing tumors. However, the great toxic and side effects associated with them greatly restrict the clinical use of such molecules. Therefore, while cytokines represented by modified IL-2 have become the top priority in the pipeline layout of numerous pharmaceutical companies, various design strategies for reducing toxicity and enhancing efficacy for IL-2 and IL-15 have been disclosed. In 2022, the Chinese Patent No. CN114380919A discloses a brand-new IL-2 design strategy. In this strategy, the sequence responsible for binding to CD25 (i.e., IL-2Rα) and some other sequences in the IL-2 molecule are replaced with the corresponding sequences in IL-15, forming a brand-new cytokine (S-unit molecule) that binds to the CD215 fragment (IL-15Rα) to form a stable complex (L-unit molecule). The complex L-unit is a brand-new cytokine with strong cytological activity and anti-tumor activity. In 2021, Roche reported that a fusion protein of PD-1 antibody and IL-2 mutant (IL-2v) has stronger anti-tumor activity than the PD-1 antibody alone and can overcome immune checkpoint tolerance. In September 2022, Roche published a study entitled "PD-1-cis IL-2R agonism yields better effectors from stem-like CD8+ T cells" in Nature again. In various in vivo tumor efficacy models, the study confirmed that compared to PD-1 antibody monotherapy, IL-2v monotherapy, and combination therapy thereof, the PD1-IL2v fusion protein exhibits stronger tumor growth inhibition capability, has better survival benefits, and significantly expands the number of antigen-specific PD-1+ TCF-1+ stem-like T cells. Although both biological mechanisms and preclinical efficacy experiments have shown that the PD1-IL2v fusion protein has stronger anti-tumor activity than PD-1 antibody or IL-2v alone, many problems exist in the actual design of the drug molecule. In one aspect, there is a huge difference in the half-lives of the PD-1 antibody and IL-2 in humans. According to literature reports, the half-life of the PD-1 antibody in humans can be as long as 20 days (Teresa C. Longoria et al., Expert Opin Drug Metab Toxicol. 2016 Oct; 12: 1247-1253), whereas the half-life of aldesleukin (wild-type IL-2) in humans is only about 5-7 minutes (M T Lotze et al., J Immunol. 1985 Jan; 134(1): 157-66.), with a difference of 3000-fold or higher between the two, which makes them unsuitable for direct development as a fusion protein. In another aspect, there is also a huge difference in the administration dosages of PD-1 antibody and IL-2 molecule in clinical practice. Clinically, the administration dose of the PD-1 antibody (Keytruda) is 200-400 mg each time, equivalent to about 2-5 mg/kg, whereas the administration dose of wild-type IL-2 (aldesleukin) is only 0.037 mg/kg, with a difference of 50-100-fold between the two, which also makes them unsuitable for direct development as a fusion protein. Therefore, there is a need in the art for a product that can match an immune checkpoint antibody and a cytokine in terms of half-life and administration dose to achieve uniformity. SUMMARY In view of this, in a first aspect, the present disclosure provides a complex of an antibody and IL-2, comprising: an immune checkpoint antibody and an IL15Rα receptor domain that are covalently linked, andan IL-2/15 chimera (S-unit molecule) non-covalently complexed with the IL15Rα receptor domain, or a variant thereof. In some specific embodiments, the IL-2/15 chimera comprises substituting a region in an IL-2 molecule that mediates binding of the IL-2 molecule to IL2Rα with a region in an