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CN-121986116-A - Fully human antibody targeting BAFF-R, CAR-T cell and application thereof

CN121986116ACN 121986116 ACN121986116 ACN 121986116ACN-121986116-A

Abstract

Fully human single domain antibodies, monoclonal antibodies, bispecific antibodies, CAR-T cells targeting BAFF-R and uses thereof. Fully human antibodies or antigen binding fragments thereof targeting BAFF-R, fully human Chimeric Antigen Receptors (CARs) targeting BAFF-R and immune cells expressing the CARs, obtained by screening a fully human phage library are provided. Bispecific antibodies targeting different combination configurations of BAFF-R and CD3 are also provided. Also provided are uses of these antibodies and CAR-immune cells in the treatment of B cell tumors.

Inventors

  • TAN TAOCHAO
  • LIU JIANWEI
  • LUO QIAN
  • WEI QIAOE
  • JIA XIANGYIN
  • YANG YONGKUN
  • XIE MENG
  • XU LE

Assignees

  • 南京驯鹿生物技术股份有限公司
  • 南京驯鹿生物医药有限公司

Dates

Publication Date
20260505
Application Date
20240927
Priority Date
20230928

Claims (16)

  1. A single domain antibody targeting a B cell activating factor receptor (BAFF-R), wherein a VHH chain of the single domain antibody comprises complementarity determining regions CDR1 shown in SEQ ID NO.27, CDR2 shown in SEQ ID NO.28 and CDR3 shown in SEQ ID NO. 29; Any of the above amino acid sequences further includes derivative sequences optionally having at least one amino acid added, deleted, modified and/or substituted and capable of retaining BAFF-R binding affinity.
  2. An antibody targeting the B cell activating factor receptor (BAFF-R), wherein the heavy chain variable region of the antibody comprises complementarity determining regions CDR1 shown in SEQ ID NO.27, CDR2 shown in SEQ ID NO.28 and CDR3 shown in SEQ ID NO.29, or The light chain variable region of the antibody comprises CDRs of complementarity determining regions including CDR1 shown in SEQ ID NO.36, CDR2 shown in AAS and CDR3 shown in SEQ ID NO.37, and the heavy chain variable region of the antibody comprises CDRs of complementarity determining regions including CDR1 shown in SEQ ID NO.38, CDR2 shown in SEQ ID NO.39 and CDR3 shown in SEQ ID NO. 40; Any of the above amino acid sequences further includes derivative sequences optionally having at least one amino acid added, deleted, modified and/or substituted and capable of retaining BAFF-R binding affinity.
  3. The antibody of claim 2, wherein the heavy chain variable region has the amino acid sequence set forth in SEQ ID No.25 or an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% identity thereto.
  4. The antibody of claim 2, wherein the light chain variable region has an amino acid sequence as set forth in SEQ ID No.30 or an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% identical thereto, and the heavy chain variable region has an amino acid sequence as set forth in SEQ ID No.32 or an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% identical thereto.
  5. A chimeric antigen receptor, characterized in that the antigen binding domain of the chimeric antigen receptor comprises an antigen binding fragment targeting BAFF-R, the heavy chain variable region of which comprises complementarity determining regions CDR1 shown in SEQ ID NO.27, CDR2 shown in SEQ ID NO.28 and CDR3 shown in SEQ ID NO. 29; Or the light chain variable region of the antigen binding fragment comprises the complementarity determining regions CDR1 shown in SEQ ID NO.36, CDR2 shown in AAS and CDR3 shown in SEQ ID NO.37, and the heavy chain variable region of the antibody comprises the complementarity determining regions CDR1 shown in SEQ ID NO.38, CDR2 shown in SEQ ID NO.39 and CDR3 shown in SEQ ID NO. 40.
  6. A multispecific antibody comprising a single domain antibody that targets BAFF-R according to claim 1 or an antibody that targets BAFF-R according to claim 2.
  7. A bispecific antibody, characterized in that the bispecific antibody comprises: A first antigen binding region that targets BAFF-R, and A second antigen binding region that targets CD3, wherein, The first antigen binding region that targets BAFF-R comprises the complementarity determining regions CDR1 shown in SEQ ID NO.27, CDR2 shown in SEQ ID NO.28 and CDR3 shown in SEQ ID NO. 29.
  8. The bispecific antibody of claim 7, wherein the bispecific antibody has the structure: (a) The heavy chain comprises an anti-BAFF-R VH, an anti-CD3VH, an antibody heavy chain constant region (CH 1) and a human IgG Fc region from the N end to the C end in sequence, and a second heavy chain comprises the anti-BAFF-R VH and the human IgG Fc region from the N end to the C end in sequence; (b) A light chain comprising, in order from N-terminus to C-terminus, anti-CD3 VL, an antibody light chain constant region (CL), Wherein disulfide bonds exist between the antibody heavy chain constant region (CH 1) and the antibody light chain constant region (CL); Alternatively, the bispecific antibody has the following structure: (a) Two identical heavy chains comprising, in order from N-terminal to C-terminal, an anti-BAFF-R VH, an anti-CD3VH, an antibody heavy chain constant region (CH 1), a human IgG Fc region; (b) Two identical light chains comprising, in order from N-terminal to C-terminal, anti-CD3 VL, an antibody light chain constant region (CL), Wherein disulfide bonds exist between the antibody heavy chain constant region (CH 1) and the antibody light chain constant region (CL).
  9. A recombinant protein, said recombinant protein comprising: (i) A single domain antibody targeting BAFF-R according to claim 1, a BAFF-R antibody targeting BAFF-R according to any one of claims 2 to 4, a chimeric antigen receptor according to claim 5, a multispecific antibody according to claim 6, or a bispecific antibody according to claim 7, and (Ii) Optionally a polypeptide molecule or fragment having therapeutic functions, and/or (Iii) Optionally a functional domain which enhances the physicochemical properties or the patentability of the protein.
  10. A nucleic acid molecule, wherein said nucleic acid molecule encodes a polypeptide selected from the group consisting of: (1) A single domain antibody targeting BAFF-R according to claim 1, a BAFF-R antibody targeting BAFF-R according to any one of claims 2 to 4, a chimeric antigen receptor according to claim 5, a multispecific antibody according to claim 6, or a bispecific antibody according to claim 7, or (2) The recombinant protein of claim 9.
  11. A vector comprising the nucleic acid molecule of claim 10.
  12. A host cell comprising the vector of claim 11 or the nucleic acid molecule of claim 10 integrated into a chromosome.
  13. An engineered immune cell comprising the vector of claim 11, or a chromosome having incorporated therein an exogenous nucleic acid molecule of claim 10, or expressing the antibody of claim 1 or the chimeric antigen receptor of claim 5.
  14. An immunoconjugate characterized in that, the immunoconjugate comprises: (a) An antibody moiety which is a BAFF-R targeting single domain antibody according to claim 1, a BAFF-R targeting antibody according to any one of claims 2 to 4, a multispecific antibody according to claim 6, or a bispecific antibody according to claim 7, and (B) A coupling moiety coupled to the antibody moiety, the coupling moiety selected from the group consisting of a detectable label, a drug, a toxin, a cytokine, an enzyme, or a combination thereof.
  15. A pharmaceutical composition or formulation comprising: (i) The single domain BAFF-R-targeting antibody of claim 1, the BAFF-R-targeting antibody of any one of claims 2 to 4, the multispecific antibody of claim 6, or the bispecific antibody of claim 7, the recombinant protein of claim 9, the engineered immune cell of claim 13, or the immunoconjugate of claim 14, and (Ii) A pharmaceutically acceptable carrier.
  16. Use of an active ingredient selected from the group consisting of a single domain antibody targeting BAFF-R according to claim 1, a targeted BAFF-R antibody according to any one of claims 2-4, a multispecific antibody according to claim 6, or a bispecific antibody according to claim 7, a recombinant protein according to claim 9, an engineered immune cell according to claim 13, or an immunoconjugate according to claim 14, or a combination thereof, for (a) preparing a detection reagent, a detection plate or a kit, and/or (b) preparing a medicament for preventing and/or treating a BAFF-R related disease.

Description

Fully human antibody targeting BAFF-R, CAR-T cell and application thereof Technical Field The application relates to the field of biological medicine, in particular to a full-human single domain antibody targeting BAFF-R, a monoclonal antibody, a bispecific antibody, a CAR-T cell and application of CAR-T treatment thereof. Background Lymphoma is a malignant tumor of the primary lymph node and extranodal lymphoid tissue, accounting for 3% -4% of all malignant tumors in China, and is the first major malignant tumor of the blood system. The two most common subtypes of B-cell lymphomas are diffuse large B-cell lymphoma (DLBCL) and Follicular Lymphoma (FL). Diffuse large B-cell lymphoma (DLBCL) is the most common invasive B-NHL, accounting for approximately 30% of newly diagnosed NHL cases. At present, the standard first-line therapy R-CHOP still has 10% of primary treatment DLBCL as refractory cases, and 40% of primary treatment effective patients recur 1 after 2-5 years. Autologous hematopoietic stem cell transplantation (ASCT) after CR or PR has been reached after chemotherapy is the best treatment regimen for current relapse refractory DLBCL, but 2 years after transplantation the disease-free survival rate is still not 15%. Follicular Lymphoma (FL) is the most common indolent B-NHL, accounting for approximately 22% of newly diagnosed NHL cases. Although slow in progression, it is generally considered incurable, and a median survival time of about 10 years is expected, with about 15-28% of FL being converted to invasive lymphoma within 10 years. Current CAR-T therapies for B cell lymphomas are primarily based on the CD19 target. There are 4 versions of CD19-CAR-T on the market. The major indications for the four CD19-CAR-T are B cell lymphoma (DLBCL) and Follicular Lymphoma (FL) with ORR of about 70% -80% and CR of 50-60%. Although both major B-NHLs achieved higher remission rates than standard therapies for CD19 CAR-T treatment, follow-up studies showed that some patients relapsed due to antigen escape, i.e. mutations or deletions of CD19 protein expressed on the tumor cell surface turned negative to disable CAR-T cell treatment, at a ratio of about 10% -20%2. Thus, there is a need for CAR-T cell immunotherapy that seeks new targets for patients with relapsed refractory disease. BAFF-R (B-CELL ACTIVATING factor receptor) belongs to a member of the tumor necrosis factor (tumor necrosis factor, TNF) receptor superfamily. BAFF-R is expressed on the surface of peripheral B cells except plasma cells and central blast cells located in the germinal center dark region. Researchers tested 116 clinical samples of B cell lymphomas and found high expression of BAFF-R on a variety of B lymphoma cells, including chronic lymphocytic leukemia (chronic lymphocytic leukemia, CLL) (21/21, 100%), mantle cell lymphoma (MANTLE CELL lymphoma, MCL) (7/7, 100%), FL (13/16,81%), and DLBCL (14/18,78%) 3. Thus, BAFF-R can be used as a new target for treating B cell tumors besides CD 19. Thus, BAFF-R is an effective therapeutic target for a variety of B lymphocyte tumors, autoimmune diseases, and other diseases characterized by BAFF-R expression. The development of BAFF-R targeting immunotherapeutic products has very important significance and application value. Disclosure of Invention The invention aims to provide a full human single domain antibody, a monoclonal antibody, a bispecific antibody, a CAR-T cell and application thereof for targeting BAFF-R. The invention aims at providing an antibody targeting BAFF-R, a CAR and a host cell expressing the CAR targeting BAFF-R, and a preparation method and application thereof. It is another object of the present invention to provide a method for constructing and preparing a bispecific antibody targeting BAFF-R and CD3, a method for evaluating biological activity, and a method for evaluating safety. In a first aspect of the invention there is provided a single domain antibody targeting the B cell activating factor receptor (BAFF-R) the VHH chain of which comprises complementarity determining regions CDR1 shown in SEQ ID NO.27, CDR2 shown in SEQ ID NO.28 and CDR3 shown in SEQ ID NO. 29; Any of the above amino acid sequences further includes derivative sequences optionally having at least one amino acid added, deleted, modified and/or substituted and capable of retaining BAFF-R binding affinity. In another preferred embodiment, the VHH chain of the single domain antibody further comprises a Framework Region (FR). In another preferred embodiment, the framework region FR is of human, murine, rabbit or camel origin. In another preferred embodiment, the framework region FR comprises an FR region of human origin, an FR region of murine or camel origin. In another preferred embodiment, the VHH chain of the single domain antibody targeting BAFF-R has the amino acid sequence shown as SEQ ID NO.20 or an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,