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US-20260125447-A1 - FC VARIANTS WITH ALTERED BINDING TO NEONATAL FC RECEPTOR (FCRN) FOR VETERINARY USE

US20260125447A1US 20260125447 A1US20260125447 A1US 20260125447A1US-20260125447-A1

Abstract

Provided are various embodiments relating to variant IgG Fc polypeptides with altered FcRn binding activity. Also provided are polypeptides and pharmaceutical compositions comprising the variant IgG Fc polypeptides described herein. Polypeptides comprising variant IgG Fc polypeptides of the present invention may have extended half-life in vivo. Such products may be used in methods to treat disease in companion animals, such as canines, felines, and equines.

Inventors

  • Hangjun Zhan
  • Lam Nguyen
  • QINGYI CHU
  • Richard Chin
  • Shyr Jiann Li

Assignees

  • ELANCO US INC.

Dates

Publication Date
20260507
Application Date
20250703

Claims (20)

  1. 1 . An antibody comprising: a modified canine IgG Fc domain having a modified canine IgG-Fc amino acid sequence comprising at least one amino acid substitution relative to a wild-type canine IgG Fc amino acid sequence of a wild-type canine IgG Fc domain, wherein the at least one amino acid substitution comprises an amino acid substitution at a position 208 as numbered with respect to SEQ ID NOS: 2 or 3, or at a position 209 as numbered with respect to SEQ ID NOS: 1 or 4, wherein the modified canine IgG-Fc amino acid sequence is at least 90% identical to the wild-type canine IgG Fc amino acid sequence, wherein the modified canine IgG Fc domain binds to a neonatal Fc receptor (FcRn) with an increased affinity relative to the wild-type canine IgG Fc domain, and wherein the antibody has an extended in vivo half-life relative to a reference antibody having the wild-type canine IgG Fc domain.
  2. 2 . The antibody of claim 1 , wherein the wild-type canine IgG Fc domain is a wildtype canine IgG-A Fc domain, IgG-B Fc domain, IgG-C Fc domain, or IgG-D Fc domain.
  3. 3 . The antibody of claim 1 , wherein the wild-type canine IgG Fc amino acid sequence comprises SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, or SEQ ID NO: 4.
  4. 4 . The antibody of claim 1 , wherein the modified canine IgG-Fc amino acid sequence is at least 95%, at least 98%, or at least 99% identical to the wild-type canine IgG Fc amino acid sequence.
  5. 5 . The antibody of claim 1 , wherein the amino acid substitution at a position 208 as numbered with respect to SEQ ID NOS: 2 or 3, or at a position 209 as numbered with respect to SEQ ID NOS: 1 or 4 the at least one amino acid substitution is a first amino acid substitution and the at least one amino acid substitution further comprises: a) at least one further amino acid substitution at at least one position corresponding to position 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 31, 60, 79, 80, 83, 132, 149, 162, 183, 203, and/or 205 of SEQ ID NO: 1; b) at least one further amino acid substitution at at least one position corresponding to position 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 31, 60, 79, 80, 81, 83, 132, 148, 162, 182, 202, 204, and/or 213 of SEQ ID NO: 2; c) at least one further amino acid substitution at at least one position corresponding to position 9, 18, 22, 23, 24, 26, 27, 28, 30, 31, 60, 79, 80, 81, 83, 132, 148, 162, 182, 202, and/or 204 of SEQ ID NO: 3; or d) at least one further amino acid substitution at at least one position corresponding to position 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 60, 79, 80, 83, 132, 149, 163, 183, 203, and/or 205 of SEQ ID NO: 4.
  6. 6 . The antibody of claim 1 , wherein the amino acid substitution at a position 208 as numbered with respect to SEQ ID NOS: 2 or 3, or at a position 209 as numbered with respect to SEQ ID NOS: 1 or 4 the at least one amino acid substitution is a first amino acid substitution and the at least one amino acid substitution further comprises: a) at least one further amino acid substitution at at least one position selected from 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 31, 60, 79, 80, 83, 132, 149, 162, 183, 203, and/or 205 of SEQ ID NO: 1; b) at least one amino further acid substitution at at least one position selected from position 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 31, 60, 79, 80, 81, 83, 132, 148, 162, 182, 202, 204, and/or 213 of SEQ ID NO: 2; c) at least one further amino acid substitution at at least one position selected from position 9, 18, 22, 23, 24, 26, 27, 28, 30, 31, 60, 79, 80, 81, 83, 132, 148, 162, 182, 202, and/or 204 of SEQ ID NO: 3; or d) at least one further amino acid substitution at at least one position selected from position 9, 18, 22, 23, 24, 25, 26, 27, 28, 30, 60, 79, 80, 83, 132, 149, 163, 183, 203, and/or 205 of SEQ ID NO: 4.
  7. 7 . The antibody of claim 1 , wherein the at least one amino acid substitution comprises at least one conservative substitution.
  8. 8 . The antibody of claim 1 , wherein the at least one amino acid substitution comprises alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, or valine, or any combination thereof.
  9. 9 . The antibody of claim 1 , wherein the at least one amino acid substitution comprises substitution of asparagine with glutamine, histidine, aspartic acid, lysine, or arginine.
  10. 10 . The antibody of claim 1 , wherein the at least one amino acid substitution comprises substitution of asparagine with histidine.
  11. 11 . The antibody of claim 1 , wherein the amino acid substitution at a position 208 as numbered with respect to SEQ ID NOS: 2 or 3, or at a position 209 as numbered with respect to SEQ ID NOS: 1 or 4 is a substitution of asparagine with glutamine, histidine, aspartic acid, lysine, or arginine.
  12. 12 . The antibody of claim 1 , wherein the amino acid substitution at a position 208 as numbered with respect to SEQ ID NOS: 2 or 3, or at a position 209 as numbered with respect to SEQ ID NOS: 1 or 4 is a substitution of asparagine with histidine.
  13. 13 . The antibody of claim 1 , wherein the amino acid substitution is at a position 208 as numbered with respect to SEQ ID NO: 2 and is a substitution of asparagine with histidine.
  14. 14 . The antibody of claim 1 , wherein the modified canine IgG Fc domain binds to a neonatal Fc receptor (FcRn) with an increased affinity relative to the wild-type canine IgG Fc domain.
  15. 15 . The antibody of claim 1 , wherein the modified canine IgG Fc domain binds to a neonatal Fc receptor (FcRn) with an increased affinity relative to the wild-type canine IgG Fc domain at a pH in the range of from about 5.0 to about 6.5.
  16. 16 . An isolated nucleic acid encoding the antibody of claim 1 .
  17. 17 . A host cell comprising the nucleic acid of claim 16 .
  18. 18 . A method of producing an antibody, the method comprising culturing the host cell of claim 17 and isolating the antibody.
  19. 19 . A pharmaceutical composition comprising the antibody of claim 1 and a pharmaceutically acceptable carrier.
  20. 20 . A method of delivering the antibody of claim 1 to a dog, the method comprising administering the antibody of claim 1 to the dog.

Description

This application is a Divisional Application of U.S. patent application Ser. No. 17/284,875, filed 13 Apr. 2021, which is a U.S. National Stage application of International Application No. PCT/US2019/057093, filed 18 Oct. 2019, which claims the benefit of U.S. Provisional Application No. 62/747,613, filed 18 Oct. 2018, and U.S. Provisional Application No. 62/809,715, filed 24 Feb. 2019, each of which is incorporated by reference herein in its entirety for any purpose. BACKGROUND Field REFERENCE TO SEQUENCE LISTING SUBMITTED AS AN XML FILE Pursuant to the EFS-Web legal framework and 37 C.F.R. § 1.831-1.834 (see M.P.E.P. § 2412), a Sequence Listing in the form of an XML file. entitled “2920951-461003_Sequence_Listing” created on 2 Jul. 2025, and 214,311 bytes in size, is submitted concurrently with the instant application, and the entire contents of the Sequence Listing are incorporated herein by reference. This present disclosure relates to variant IgG Fc polypeptides of companion animals with altered binding affinity to FcRn, such as enhanced binding affinity to FcRn at acidic pH (e.g., at a pH in the range of from about 5.0 to about 6.5). The variant IgG Fc polypeptides of the present disclosure may extend the half-life or improve pharmacokinetics of an antibody or IgG Fc fusion protein in vivo. In addition, variant IgG Fc polypeptides may be used in the design and production of antibodies or fusion proteins for treating various disorders in companion animals. The neonatal Fc receptor (FcRn) is an Fc receptor that is similar in structure to the MHC class I molecules. Like MHC class I molecules, FcRn also associates with beta-2-microglobulin (B2M). FcRn is understood to facilitate transcytosis and recycling of IgG in vivo, and hence increase the in vivo half-life of IgG compared to that of other antibody isotypes. To improve the binding affinity of IgG to FcRn at an acid pH (e.g., at a pH in the range of from about 5.0 to about 6.5), the Fc region of IgG responsible for binding to FcRn may be modified through mutagenesis. Companion species animals, such as cats, dogs, and horses, have species specific IgG Fc sequences. Furthermore, there are multiple IgG subclasses, each having Fc sequence differences. For example, canine has IgG-A, IgG-B, IgG-C and IgG-D. SUMMARY Embodiment 1. A polypeptide comprising a variant IgG Fc polypeptide comprising at least one amino acid substitution relative to a wild-type IgG Fc polypeptide derived from a companion animal species, wherein the variant Fc polypeptide is capable of binding to neonatal Fc receptor (FcRn) with an increased affinity relative to the wild-type Fc polypeptide. Embodiment 2. The polypeptide of embodiment 1, wherein the variant Fc polypeptide binds to FcRn with an affinity greater than the wild-type IgG Fc polypeptide, as measured by biolayer interferometry, surface plasmon resonance, or any protein-protein interaction tool at a pH in the range of from about 5.0 to about 6.5, such as at a pH of about 5.0, a pH of about 5.2, a pH of about 5.5, a pH of about 6.0, a pH of about 6.2, or a pH of about 6.5. Embodiment 3. The polypeptide of embodiment 1 or embodiment 2, wherein the variant IgG Fc polypeptide binds to FcRn with a dissociation constant (Kd) of less than 5×10−6 M, less than 1×10−6 M, less than 5×10−7 M, less than 1×10−7 M, less than 5×10−8 M, less than 1×10−8 M, less than 5×10−9 M, less than 1×10−9 M, less than 5×10−10 M, less than 1×10−10 M, less than 5×10−11 M, less than 1×10−11 M, less than 5×10−12 M, or less than 1×10−12 M, as measured by biolayer interferometry, surface plasmon resonance, or any protein-protein interaction tool at a pH in the range of from about 5.0 to about 6.5, such as at a pH of about 5.0, a pH of about 5.5, a pH of about 6.0, or a pH of about 6.5. Embodiment 4. The polypeptide of any one of the preceding embodiments, wherein the polypeptide has increased serum half-life relative to a polypeptide comprising a wild-type Fc. Embodiment 5. The polypeptide of any one of the preceding embodiments, wherein the companion animal species is canine, feline, or equine. Embodiment 6. The polypeptide of any one of the preceding embodiments, wherein the wild-type IgG Fc polypeptide is a) a canine IgG-A Fc, IgG-B Fc, IgG-C Fc, or IgG-D Fc;b) an equine IgG1 Fc, IgG2 Fc, IgG3 Fc, IgG4 Fc, IgG5 Fc, IgG6 Fc, or IgG7 Fc; orc) a feline IgG1 Fc, or IgG2 Fc. Embodiment 7. The polypeptide of any one of the preceding embodiments, wherein the variant IgG Fc polypeptide is at least 90% identical, at least 95% identical, at least 97% identical, or at least 99% identical to the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID