CN107773762B

CN107773762B - ADC based on PD-L1 antibody coupling chemotherapeutic drug, and preparation method and application thereof

Info

Publication number: CN107773762B
Application number: CN201610792030.XA
Authority: CN
Inventors: 张莉; 张付雷; 王颖; 董霞
Original assignee: Shanghai Ganyun Biotechnology Co ltd
Current assignee: Shanghai Ganyun Biotechnology Co ltd
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2021-06-15
Anticipated expiration: 2036-08-31
Also published as: CN107773762A

Abstract

The invention belongs to the field of drug research and development, and particularly relates to an ADC based on a PD-L1 antibody coupling chemotherapeutic drug, and a preparation method and application thereof. Based on an antibody coupling technology, the invention utilizes the targeting property of the PD-L1 antibody but is not limited to the anticancer properties of the PD-L1 antibody, an antitumor drug maytansine (DM1) and analogues thereof to form an immune-drug system; the immune-drug system not only keeps the targeting property of a single PD-L1 antibody and the strong killing property of a single chemotherapeutic drug to tumors, but also effectively enriches a large amount of DM1 to tumor parts and reduces the dosage of the drug, thereby reducing the killing of the drug to normal tissues and reducing the toxic and side effects of the drug.

Description

ADC based on PD-L1 antibody coupling chemotherapeutic drug, and preparation method and application thereof

Technical Field

The invention belongs to the field of drug research and development, and particularly relates to an ADC based on a PD-L1 antibody coupling chemotherapeutic drug, and a preparation method and application thereof.

Background

Tumors are one of three major diseases that present serious threats to human health. Cancer patients and death cases are increasing in 2012 globally, and nearly half of new cancer cases appear in asia, most of which are in china, and the new cancer cases in china are the first to be higher. Of the 4 malignant tumors of liver, esophagus, stomach and lung, the number of new cases and deaths in China all dominate the world. Meanwhile, 2012 year data issued by national tumor registration center shows that about 350 ten thousand new cancer cases and about 250 ten thousand people die each year in China. The malignant gastric cancer has poor treatment effect, high late-stage metastasis rate and poor prognosis. At present, the conventional treatment methods such as surgical treatment, radiotherapy, chemotherapy and immunotherapy are adopted clinically, but the chemotherapy or radiotherapy can not change the survival period of the patient, and even the cancer patient sensitive to the first chemotherapy is easy to relapse or generate drug resistance. And the curative effect is obviously reduced when chemotherapy or radiotherapy is carried out again after the relapse. Therefore, for most patients with unavoidable relapse and low cure rate, low toxicity and more effective targeted therapy are very necessary. In recent years, antibody-targeted therapies directed against cell surface molecules have made tremendous progress. In the process of anti-tumor therapy, the antibody targeted therapy has the characteristics of high specificity, small side effect, long half-life period and the like, so that the method becomes a biological therapy method for tumors with a great development prospect. However, the monoclonal antibody has mild effect on tumor.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide an ADC based on a PD-L1 antibody coupling chemotherapeutic drug, and a preparation method and application thereof.

In order to achieve the above objects and other related objects, the present invention adopts the following technical solutions:

in a first aspect of the invention, there is provided an antibody-drug conjugate comprising a cytotoxic drug, an antibody and a conjugate chain conjugating the antibody and the toxic drug.

Preferably, the cytotoxic drug is selected from, but not limited to, maytansine DM 1.

Preferably, the antibody is selected from, but not limited to, programmed death ligand-1 PD-L1.

Preferably, the coupling chain is selected from, but not limited to, 3- (2-pyridyldithio) propionylhydrazine PDPH.

Preferably, the molar ratio of the maytansine DM1 to the programmed death ligand-1 PD-L1 is (1-2): 1.

preferably, the-S-group of the coupling chain PDPH is linked to the-SH group of maytansine DM 1.

Preferably, the-NH of the PDPH chain is coupled₂The group is linked to the-COOH group of programmed death ligand-1 PD-L1.

In a second aspect of the present invention, there is provided a method for preparing the aforementioned antibody-drug conjugate, comprising:

(1) synthesis of maytansine DM1 with a hydrazide group (DM 1-PDPH): dissolving maytansine DM1 and 3- (2-pyridine dithio) propionyl hydrazine PDPH, and reacting;

(2) preparation of oxidized programmed death ligand-1 PD-L1: mixing PD-L1 with an oxidation buffer solution for oxidation;

(3) preparation of PD-L1-DM 1: mixing the maytansine DM1 with the hydrazide group obtained in the step (1) and the oxidized programmed death ligand-1 obtained in the step (2), and reacting to obtain PD-L1-DM 1.

Preferably, in step (1), maytansine DM1 and 3- (2-pyridyldithio) propionylhydrazine PDPH are dissolved in methanol.

Preferably, in step (2), the oxidation buffer solution is sodium iodate oxidation buffer solution.

Preferably, in step (3), the reaction is carried out at room temperature.

In a third aspect of the invention, the use of the antibody-drug conjugate in the preparation of a tumor treatment drug is provided.

Preferably, the tumor treatment drug is selected from, but not limited to, lung cancer treatment drugs.

In a fourth aspect of the present invention, a pharmaceutical composition for treating tumor is provided, wherein the active ingredient of the pharmaceutical composition comprises the antibody-drug conjugate.

Preferably, in the pharmaceutical composition, the antibody-drug conjugate is one or the only active ingredient of the pharmaceutical composition.

Preferably, the pharmaceutical composition further comprises a pharmaceutically acceptable carrier.

When the pharmaceutical composition is used, the antibody-drug conjugate is used as the only effective component, or the antibody-drug conjugate is used as one of the effective components, and can be mixed with one or more pharmaceutically acceptable carriers or excipients to prepare pharmaceutical dosage forms with different administration routes.

Preferably, the pharmaceutical composition is formulated in the form of a tablet, a capsule, a powder, a granule, a syrup, a solution, an oral liquid, a spirit, a tincture, an aerosol, a powder cloud, an injection, a sterile powder for injection, or a suppository. The above formulation types can be understood in terms of the relevant definitions in pharmacy (sixth edition, people health Press, Toruford), and the preparation of the above formulations can be formulated in terms of the relevant formulations in pharmacy (sixth edition, people health Press, Toford).

The dosage of the pharmaceutical composition is within the knowledge of the clinician. The effective dose of the aforementioned antibody-drug conjugate as an active ingredient may vary depending on the mode of administration and the severity of the disease. For most large mammals, the antibody-drug conjugate is administered in an amount of about 0.01 to 1000mg per day. Preferably, the clinical dose for adults is in the range of 0.01-200 mg/day, more preferably 0.05-100 mg/day.

In a fifth aspect of the invention, there is provided a method for treating a tumor, comprising administering the aforementioned tumor treating drug to a patient.

Compared with the prior art, the invention has the following beneficial effects:

the antibody coupling-based technology aims to form an immune-drug system by utilizing the targeting property of a PD-L1 antibody but not only limited to the anticancer properties of the PD-L1 antibody and an antitumor drug maytansine (DM1) and analogues thereof; the immune-drug system not only keeps the targeting property of a single PD-L1 antibody and the strong killing property of a single chemotherapeutic drug to tumors, but also effectively enriches a large amount of DM1 to tumor parts and reduces the dosage of the drug, thereby reducing the killing of the drug to normal tissues and reducing the toxic and side effects of the drug.

Drawings

FIG. 1: synthesis of DM1 Compound with a hydrazide group (DM 1-PDPH).

FIG. 2: schematic synthesis of PD-L1-DM 1.

FIG. 3: standard curve of DM 1.

FIG. 4: is a diagram of the in vitro cytotoxic effect of PD-L1-DM 1.

FIG. 5: is a flow-through image of the antibody activity of PD-L1-DM 1.

FIG. 6: is a confocal laser detection image of the antibody activity of PD-L1-DM 1.

FIG. 7: is a diagram of the in vivo tumor inhibition effect of PD-L1-DM 1.

FIG. 8 is a graph of the tumor-treating effect of PD-L1-DM 1.

Detailed Description

First, antibody-drug conjugates (ADC)

Antibody-drug conjugates (ADCs) are a new generation of antibody-targeted therapeutics, mainly used for the treatment of cancer and tumors. Structurally, the ADC drug consists of a "warhead" drug (cytotoxic drug), an antibody, and a portion of the conjugate chain 3 that conjugates the antibody and drug, and the cytotoxic drug is linked to the antibody protein by chemical conjugation. ADCs benefiting from stable binders can definitely carry the drug into cells with little degradation on peripheral blood and cell surfaces; under the same administration dosage, the stable ADCs can keep effective killing concentration in vivo for a long time without releasing redundant toxin more like a sustained-release agent, so that the ADCs have more efficient killing effect and less adverse reaction in the anti-tumor process.

Thus, antibody-drug conjugates (ADCs) have both overcome antibody killers to some extent

The side effect of the chemotherapy drug to normal tissues is obviously reduced while the injury is insufficient.

II, PD-L1

PD-L1 is known as Programmed Death Ligand-1 (Programmed Death Ligand-1) and is widely present on tumor cells. Many studies at present show that the PD-L1 molecules expressed in a large number in various human tumors are closely related to clinical and pathological characteristics and prognosis of patients, and become a new biological index for tumor detection and prognosis judgment. Tumor cells use this ligand to block the mutual recognition of PD-1 and B7.1 on T cells, thereby evading the monitoring of the immune system.

III, DM1

DM1 is also known as Maytansine DM1, having the english name Maytansine DM 1. CAS number: 139504-50-0.

IV, PDPH

PDPH refers to 3- (2-Pyridyldithio) propionylhydrazine, having the English name 3- (2-Pyridyldithio) propionoyl hydrazide (PDPH).

Fifthly, PD-L1-DM1

The invention relates to PD-L1-DM1, which belongs to an antibody-drug conjugate and comprises a cytotoxic drug, an antibody and a conjugate chain for coupling the antibody and the toxic drug. The cytotoxic drug is selected from, but not limited to, maytansine DM 1. The antibody is selected from, but not limited to, programmed death ligand-1 PD-L1. The coupling chain is selected from, but not limited to, 3- (2-pyridyldithio) propionylhydrazine PDPH.

The molar ratio range of the maytansine DM1 to the programmed death ligand-1 PD-L1 is (1-2): 1.

in one embodiment, the-S-group of the coupling chain PDPH is linked to the-SH group of maytansine DM 1. -NH of PDPH of the coupling chain₂The group is linked to the-COOH group of programmed death ligand-1 PD-L1.

Preparation method of VI, PD-L1-DM1

The preparation method of PD-L1-DM1 comprises the following steps:

In one example, in step (1), maytansine DM1 and 3- (2-pyridyldithio) propionylhydrazine PDPH were dissolved in methanol.

In one embodiment, in the step (2), the oxidation buffer solution is sodium iodate oxidation buffer solution.

In one embodiment, in step (3), the reaction is carried out at room temperature.

Application of seventy-five and PD-L1-DM1

The PD-L1-DM1 can be used for preparing tumor treatment medicines.

In one embodiment, the PD-L1-DM1 disclosed by the invention is prepared into a lung cancer treatment medicament, and can realize good treatment on tumor tissues.

Therefore, the PD-L1-DM1 can be used for preparing tumor treatment medicines for treating tumor diseases.

Medicine composition for treating tumor

The effective components of the pharmaceutical composition for treating tumor of the present invention contain the antibody-drug conjugates described above, for example: PD-L1-DM 1. In the pharmaceutical composition, PD-L1-DM1 is one of the effective components of the pharmaceutical composition or the only effective component. The pharmaceutical composition also comprises a pharmaceutically acceptable carrier.

A "pharmaceutically acceptable" component is one that is suitable for use in humans and/or animals without undue adverse side effects (such as toxicity, irritation, and allergic response) commensurate with a reasonable benefit/risk ratio. A "pharmaceutically acceptable carrier" is a pharmaceutically or comestibly acceptable solvent, suspension or excipient for delivering the cinnamaldehyde of the invention to an animal or human. The carrier may be a liquid or a solid.

Pharmaceutically acceptable carriers are various pharmaceutically commonly used adjuvants and/or excipients, including, but not limited to, sugars (such as lactose, glucose and sucrose), starches (such as corn starch and potato starch), cellulose and its derivatives (such as sodium carboxymethyl cellulose, ethyl cellulose and methyl cellulose), tragacanth powder, malt, gelatin, talc, solid lubricants (such as stearic acid and magnesium stearate), calcium sulfate, vegetable oils, such as peanut oil, cottonseed oil, sesame oil, olive oil, corn oil and cocoa butter, polyols (such as propylene glycol, glycerin, sorbitol, mannitol and polyethylene glycol), alginic acid, emulsifiers (such as Tween, polyoxyethylene castor oil), wetting agents (such as sodium lauryl sulfate), coloring agents, flavoring agents, tableting agents, stabilizers, antioxidants, preservatives, pyrogen-free water, isotonic saline solutions, phosphate buffers and the like; the carrier can improve the stability, activity, bioavailability and the like of the formula according to needs.

The pharmaceutical composition is in the form of tablet, capsule, powder, granule, syrup, solution, oral liquid, spirit, tincture, aerosol, powder spray, injection, sterile powder for injection, or suppository. The above formulation types can be understood in terms of the relevant definitions in pharmacy (sixth edition, people health Press, Toruford), and the preparation of the above formulations can be formulated in terms of the relevant formulations in pharmacy (sixth edition, people health Press, Toford).

Method for treating tumor

The tumor therapeutic medicine can be used for treating tumors by being applied to a patient.

Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.

Unless otherwise indicated, the experimental methods, detection methods, and preparation methods disclosed herein all employ techniques conventional in the art of molecular biology, biochemistry, chromatin structure and analysis, analytical chemistry, cell culture, recombinant DNA technology, and related arts. These techniques are well described in the literature, and may be found in particular in the study of the MOLECULAR CLONING, Sambrook et al: a LABORATORY MANUAL, Second edition, Cold Spring Harbor LABORATORY Press, 1989 and Third edition, 2001; ausubel et al, Current PROTOCOLS IN MOLECULAR BIOLOGY, John Wiley & Sons, New York, 1987 and periodic updates; the series METHODS IN ENZYMOLOGY, Academic Press, San Diego; wolffe, CHROMATIN STRUCTURE AND FUNCTION, Third edition, Academic Press, San Diego, 1998; (iii) METHODS IN ENZYMOLOGY, Vol.304, Chromatin (P.M.Wassarman and A.P.Wolffe, eds.), Academic Press, San Diego, 1999; and METHODS IN MOLECULAR BIOLOGY, Vol.119, chromatography Protocols (P.B.Becker, ed.) Humana Press, Totowa, 1999, etc.

Example 1 Synthesis of DM1 with hydrazide groups (DM1-PDPH)

According to the molar ratio of maytansine DM1 to 3- (2-pyridyldithio) propionyl hydrazine PDPH of 1:1 to 2:1, 73.83mg of maytansine DM1 and 23mg of 3- (2-pyridyldithio) propionyl hydrazine PDPH are weighed, dissolved in methanol and placed at room temperature for 2h or 4h to obtain a DM1 compound (DM1-PDPH) with a hydrazide group.

A schematic diagram of the synthesis of PDPH-DM1 is shown in FIG. 1.

EXAMPLE 2 preparation of oxidized PD-L1 antibody

The mixture was mixed with an equal volume of PD-L1 antibody in 20mM sodium iodate oxidation buffer and placed in an ice bath to react for 30 minutes in the absence of light. Excess potassium iodate was removed using a desalting column.

Example 3 preparation of PD-L1-DM1

The crosslinker-modified hydrazide group-bearing DM1 compound (DM1-PDPH) of example 1 and the oxidized PD-L1 antibody of example 2 were mixed and reacted at room temperature for 2 hours. The reaction was dialyzed against PBS or excess crosslinker-modified DM1(DM1-PDPH) was removed using a desalting column.

A schematic diagram of the synthesis of PD-L1-DM1 is shown in FIG. 2.

Example 4 amounts of each PD-L1 coupled with DM1

Measuring ultraviolet absorption values of the conjugate PD-L1-DM1 at 252nm and 280nm by adopting an ultraviolet spectrophotometry, and calculating by using a Lambert beer law to obtain a coupling rate; and (3) detecting the DM1 concentration in the prepared antibody coupling drug PD-L1-DM 1. The ultraviolet absorption of DM1 was at 252nm, and the concentration of DM1 was determined using an ultraviolet spectrophotometer. First, the ratio was diluted to obtain its standard curve: y is 0.0008x + 0.0011. 200ul of the absorbance was measured at 252nm and the absorbance was 0.08984. The concentration of DM1 obtained from the standard curve was: 0.08984 is 0.0008x +0.0011, x is 110.925 ug/ml. DM1 molecular weight of 692.2, antibody concentration of 1mg/mL, and antibody molecular weight of about 5 x 10⁴。

The number of molecules of DM1 carried per antibody molecule was:

N(DM1)/N(PD-L1)＝(110.925*10^-3/692.2)/(1/5*10⁴)＝8.0125。

that is, each PD-L1 antibody molecule carries 8.0125 molecules of DM 1.

Example 5 cytotoxicity assay

The toxicity of cells of the PD-L1 antibody, the PD-L1 antibody conjugate drug (ADC, PD-L1-DM1) was evaluated. Cell plating: taking A549 (human gastric cancer cells) in logarithmic growth phase, digesting and centrifuging HMEC-1 (human microvascular endothelial cells), counting, and laying cells in a 96-well plate with the density of 5 × 10³Per well, 100. mu.l serum-containing medium was added to each well, and a circle of blank cell wells each filled with 100. mu.l PBS and placed in 5% CO₂Overnight in a cell incubator at 37 ℃.

Coupling PD-L1 antibody and PD-L1 antibody to DM1(PD-L1-DM1), adding into cell well with the concentration of the antibody being 0.02 μ g/ml, incubating with cells, and incubating in 5% CO₂Incubating at 37 deg.C for 24 hr, discarding old culture medium, washing plate with PBS for 2 times, adding 100ul cell culture solution containing 10% CCK-8 into each well, and adding 5% CO₂Incubation at 37 ℃ for 2.5h, using BIO-TEK Elx800 reading the light absorption value of the sample hole by the full-automatic enzyme labeling instrument at the wavelength of 450nm, and calculating the cell survival rate; cell survival rate calculation method:

survival rate ═ OD_450scan-OD_450nc)/(OD_450pc-OD_450nc)×100％

Wherein, OD_450sam: the light absorption value of the experimental group at the wavelength of 450 nm;

OD_450no: the light absorption value of the negative control group at the wavelength of 450 nm;

OD_450pc: absorbance at 450nm for the positive control.

The in vitro cytotoxic effect of PD-L1-DM1 is shown in FIG. 4.

Specifically, the experimental results are shown in fig. 4A: compared with the Control group PD-L1-DM1, the drug group has little influence on HMEC-1 cells and no obvious level, which indicates that the biological safety is better.

The results of the experiment are shown in FIG. 4B: compared with a Control group, the PD-L1 antibody has obvious proliferation inhibition capacity on A549 gastric cancer cells, while the antibody coupling drug PD-L1-DM1 group has higher cell lethality rate, and is improved by nearly one time compared with the PD-L1 antibody group;

therefore, the antibody coupling drug targeting property and the tumor treatment effect of the antibody coupling drug targeting property are superior to those of the antibody drug.

Example 6 detection of antibody Activity

The study of the interaction with the cell surface is an important measure for the evaluation of the chemotherapeutic drug DM1 alone and the antibody-coupled chemotherapeutic drug PD-L1 (PD-L1-DM 1). Through research and evaluation on the interaction with the cell surface, the targeting and enriching effects in vivo can be estimated, and further the potential application value of the method can be evaluated. The specific experimental process is as follows:

(1) cell plating: a549 cells in logarithmic growth phase are digested, centrifuged and counted, and the cell density is 2 multiplied by 10 in a 24-well plate⁵Per well, 500. mu.l serum-containing medium was added to each well, and a surrounding circle of blank cell wells each filled with 500. mu.l PBS and placed in 7% CO₂Overnight in a cell incubator at 37 ℃.

(2) Respectively taking freeDM1, antibody-conjugated drug DM1(PD-L1-DM1) were added to the cell wells, incubated with A549 cells in 5% CO₂Incubate at 37 ℃ for 6 h.

(3) After 6h incubation, DM1 and ADC groups (PD-L1-DM1) were each gently washed 2 times with medium and the cell digests were centrifuged in 15ml centrifuge tubes and then washed 2 times with PBS (800 rpm. times.5 min) at a concentration of 1X 10⁶1ml each, using a secondary antibody labeled with Alexa Fluor 610 (rabbit anti-human), and detecting the red fluorescence intensity of the antibody by flow.

The results of the experiment are shown in FIG. 5: the figure shows that the antibody activity of PD-L1-DM1 is almost identical to that of PD-L1 itself, and thus it can be seen that the antibody activity of PD-L1-DM1 is not affected by conjugation.

Example 7 detection of antibody Activity

The study of the interaction with the cell surface is an important measure for the evaluation of the antibody activity of the PD-L1 antibody-conjugated chemotherapeutic drug (PD-L1-DM 1). After the antibody is coupled, the spatial structure of the antibody may be changed, and the interaction effect of the antibody on the cell surface is evaluated through laser confocal evaluation, so that the potential application value of the antibody is evaluated. The specific experimental process is as follows:

(1) cell plating: a549 cells in logarithmic growth phase are digested, centrifuged and counted, and the cell density is 2 multiplied by 10 in the confocal dish⁴The cell is placed in a dish, 1ml of serum-containing culture medium is added after the cell is attached to the wall, and the culture medium is placed in 5 percent CO₂Overnight in a cell incubator at 37 ℃.

(2) Adding free antibody PD-L1 and antibody coupling drug DM1(PD-L1-DM1) into the cell pore

In (1), incubation with A549 cells in 5% CO₂Incubate at 37 ℃ for 6 h.

(3) After 6h incubation, the DM1 group and the ADC group (PD-L1-DM1) were washed gently 2 times with the medium and then 2 times with PBS, and a secondary antibody labeled with Alexa Fluor 610 (rabbit anti-human) was used, and the green fluorescence intensity of the cell surface was measured by laser confocal measurement.

The experimental results are shown in fig. 6: it was further shown that the antibody activity of PD-L1-DM1 was almost identical to that of PD-L1 itself, and that the antibody activity of PD-L1-DM1 was not affected by conjugation.

Example 8 detection of the Effect of PD-L1-DM1 on treating tumors

Mouse tumor models were first established and then randomized into 3 groups including PBS Control (Control), PD-L1-DM1, PD-L1 and DM 1.

A lung cancer mouse tumor model (A549) is established at first, and Balb/c nude mice inoculated with A549 cells (human lung cancer cells) are randomly grouped into 3 groups including a PBS Control group (Control), a PD-L1 group and a PD-L1-DM1 group. 5 Balb/c nude mice in each group, wherein the average dose of each injection of each tumor-bearing Balb/c nude mouse is 5mg/kg, the injection is performed for 3 times, and the injection is performed once every 7 days on average. Survival of groups of tumor-bearing Balb/c nude mice inoculated with a549 cells was recorded and observed at the beginning of drug injection on the first day, and tumor size was measured and body weight was weighed every 2 days. Tumor volume calculation methods were as follows:

tumor volume calculation formula: length x width/2

And dissecting all tumor-bearing Balb/c nude mice on the 30 th day after the drug injection is carried out on the tumor-bearing Balb/c nude mice, taking out tumor tissues of the tumor-bearing Balb/c nude mice, measuring the mass and the volume of the tumor tissues of each group of the tumor-bearing Balb/c nude mice, and carrying out data processing on the tumor-bearing Balb/c nude mice.

The results are shown in figure 7, and the tumor volume decreased by 80% after treatment with PD-L1 antibody conjugated DM1 drug (PD-L1-DM 1). As shown in fig. 8, tumor volume was significantly reduced after (PD-L1-DM1) treatment. It is fully shown that the prepared PD-L1 antibody coupled DM1 drug (PD-L1-DM1) can realize good treatment on tumor tissues.

The experiment further proves that the antibody conjugate (PD-L1-DM1) synthesized by the method is improved in clinical tumor treatment. These all benefit from antibody targeting and enrichment at the tumor site and the strong cytotoxicity of DM1, which resulted in the best killing effect on tumor cells. The ADC drug (PD-L1-DM1) is a novel drug dosage form of antibody-chemotherapy complex therapy which has better market prospect.

While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. An antibody-drug conjugate comprising a cytotoxic drug selected from maytansine DM1, an antibody, and a conjugate chain coupling the antibody and the cytotoxic drug; the antibody adopts programmed death ligand-1 PD-L1, the coupling chain adopts 3- (2-pyridyldithio) propionyl hydrazine PDPH, the-S-S-group of the coupling chain PDPH is connected with the-SH group of maytansine DM1, and the-NH of the coupling chain PDPH₂The group is linked to the-COOH group of programmed death ligand-1 PD-L1.

2. The antibody-drug conjugate of claim 1, wherein the molar ratio of maytansine DM1 to programmed death ligand-1 PD-L1 is in the range of (1-2): 1.

3. a method of preparing an antibody-drug conjugate according to any one of claims 1 to 2, comprising:

4. The method of claim 3, further comprising any one or more of:

1) in the step (1), maytansine DM1 and 3- (2-pyridine dithio) propionyl hydrazine PDPH are taken to be dissolved in methanol;

2) in the step (2), the oxidation buffer solution is sodium iodate oxidation buffer solution;

3) in the step (3), the reaction is carried out at room temperature.

5. Use of the antibody-drug conjugate of any one of claims 1 to 2 in the preparation of a medicament for the treatment of a tumor.

6. A pharmaceutical composition for treating tumor, comprising the antibody-drug conjugate according to any one of claims 1 to 2 as an active ingredient.