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CN-122011190-A - Antibody for treating advanced rectal cancer and application thereof

CN122011190ACN 122011190 ACN122011190 ACN 122011190ACN-122011190-A

Abstract

The invention belongs to the technical field of biological medicines, and discloses an antibody for treating advanced rectal cancer and application thereof, wherein the antibody is a monoclonal antibody 3C1 of a targeted carcinoembryonic antigen (CEA), a heavy chain variable region (VH) sequence of the antibody is shown as SEQ ID NO. 1, a light chain variable region (VL) sequence of the antibody is shown as SEQ ID NO. 5, an indirect ELISA detection titer reaches 1:512000, an antibody conjugate (ADC) is provided, the antibody is coupled with the Raltitrexed through a linker, the Drug Antibody Ratio (DAR) is 3.0-4.0, the monomer purity is more than or equal to 95%, the antibody conjugate (ADC) can be used for treating CEA positive advanced rectal cancer, animal experiments show that the ADC tumor inhibition rate is 86% (which is obviously higher than 35% of free Raltitrexed), the weight reduction rate of mice is low, the small intestinal toxicity is light, the problems of poor targeting and high efficiency and safety of the existing drugs are solved.

Inventors

  • He Yangke

Assignees

  • 四川省医学科学院·四川省人民医院

Dates

Publication Date
20260512
Application Date
20260209

Claims (4)

  1. 1. An antibody for treating advanced rectal cancer, comprising a heavy chain variable region (VH) comprising an amino acid sequence set forth in SEQ ID No. 1 and a light chain variable region (VL) comprising an amino acid sequence set forth in SEQ ID No. 5.
  2. 2. The antibody of claim 1, wherein the amino acid sequences of complementarity determining regions CDRH-1, CDRH-2, and CDRH-3 of the VH are SEQ ID NO. 2, SEQ ID NO. 3, and SEQ ID NO. 4, respectively, and the amino acid sequences of complementarity determining regions CDRL-1, CDRL-2, and CDRL-3 of the VL are SEQ ID NO. 6, SEQ ID NO. 7, and SEQ ID NO. 8, respectively.
  3. 3. An antibody conjugate (ADC), characterized in that the ADC consists of an antibody according to claim 1 or 2, a degradable linker SPDB and raltitrexed.
  4. 4. Use of the antibody of any one of claims 1-2 or the antibody conjugate of claim 3 in the manufacture of a medicament for the treatment of advanced rectal cancer, wherein the advanced rectal cancer is carcinoembryonic antigen (CEA) positive advanced rectal cancer.

Description

Antibody for treating advanced rectal cancer and application thereof Technical Field The invention relates to the technical field of biological medicines, in particular to an antibody for treating advanced rectal cancer and application thereof, and specifically relates to a monoclonal antibody for targeting carcinoembryonic antigen (CEA), a preparation method thereof, an antibody conjugate (ADC) formed by coupling the antibody and a cytotoxic drug, namely Raltitrexed, and application of the monoclonal antibody and the ADC in preparation of a drug for treating CEA positive advanced rectal cancer, which are particularly suitable for patients with advanced rectal cancer with poor tolerance to traditional chemotherapy and need accurate targeting treatment. Background Advanced rectal cancer is a globally high-grade malignant tumor of the digestive tract, the incidence rate is five times before the malignant tumor, the annual new cases in China are more than 50 ten thousand, about 40% of patients already progress to advanced stages when they are diagnosed, the opportunity of radical operation is lost, and chemotherapy becomes the core means for prolonging the survival period. However, the existing first-line chemotherapeutics (such as fluorouracil, oxaliplatin and irinotecan) have the defects of poor targeting and wide systemic distribution, and are easy to cause toxicity to normal tissues such as gastrointestinal mucosa, bone marrow hematopoietic cells and the like after administration, so that serious adverse reactions such as nausea, vomiting, diarrhea, leucopenia and the like are caused, about 30% of patients are forced to reduce or stop taking medicines due to intolerance of toxicity, and the treatment effect and the life quality of the patients are difficult to be compatible. Carcinoembryonic antigen (CEA) is a characteristic tumor marker of advanced rectal cancer, is highly expressed on the surface of more than 90% of advanced rectal cancer cells, is low-expressed or not-expressed in tissues such as normal gastrointestinal mucosa, liver and the like, has the advantage of tumor-specific targeting, and becomes an ideal target for accurate treatment of advanced rectal cancer. However, the existing anti-CEA monoclonal antibody has obvious technical shortboards that most antibodies have insufficient affinity, the indirect ELISA detection titer is more than 1:100000, the CEA on the surface of the tumor is difficult to be combined with the indirect ELISA detection titer, part of antibodies can be combined with CEA, but the drug delivery cannot be mediated effectively, the tumor inhibition rate of independent administration is less than 30%, high-dose chemotherapeutic drugs are still needed in combined chemotherapy, the toxicity problem cannot be solved, and the clinical application is limited. The antibody conjugate (ADC) can improve the drug concentration at the tumor part and reduce the exposure of normal tissues through the synergistic effect of antibody targeting delivery and cytotoxicity drug killing, and is an important breakthrough direction for advanced cancer treatment. However, the traditional ADC drugs aiming at advanced rectal cancer have the key technical defects of poor stability of a linker, easiness in releasing drugs in advance in blood circulation, high free drug residue, non-uniform drug-antibody ratio (DAR) which is 1-2 at most and large fluctuation of drug effect. Therefore, development of high affinity anti-CEA antibodies, optimization of ADC coupling technology, becomes key to solving the problem of "low efficiency and high toxicity" of advanced rectal cancer treatment. Disclosure of Invention The invention firstly provides a monoclonal antibody targeting carcinoembryonic antigen (CEA), named as 3C1, which has the following core characteristics: The source and screening are that hybridoma cell 3C1 secretes, the cell is obtained by fusing Balb/C mouse immune GMP level human CEA antigen (kai cuo organisms, cat No. CEA-HM201, purity is more than or equal to 95%) and SP2/0 myeloma cell according to 10:1 proportion and 3 times of limiting dilution subcloning screening, and indirect ELISA detection shows that the antibody titer is up to 1:512000 and is obviously higher than that of the existing anti-CEA antibody; the sequence characteristics are that the amino acid sequence of a heavy chain variable region (VH) is shown as SEQ ID NO. 1, the Complementary Determining Regions (CDR) CDRH-1, CDRH-2 and CDRH-3 are respectively shown as SEQ ID NO. 2, SEQ ID NO. 3 and SEQ ID NO. 4, the amino acid sequence of a light chain variable region (VL) is shown as SEQ ID NO. 5, the CDR CDRL-1, CDRL-2 and CDRL-3 are respectively shown as SEQ ID NO. 6, SEQ ID NO. 7 and SEQ ID NO. 8, and the sequence is verified by comparison of a Kabat database, the sequence consistency of 3 positive clones is more than or equal to 99 percent, and sequencing errors are eliminated; Affinity is detected by Biacore T200, CM5 chip coup