Bispecific antibody, antibody-drug conjugate, and application thereof

Abstract

The present disclosure relates to a bispecific antibody targeting B7-H3 and EGFR, an antibody-drug conjugate (ADC) based on the bispecific antibody, a composition containing the bispecific antibody and the ADC, and a pharmaceutical use thereof.

Description

Example 5: Analysis of Antigen Binding Properties of Bispecific Antibodies ELISA for determining the antigen-binding activity of bispecific antibodies The antigen-binding activities of purified B035 and B036 from Example 4 were determined by ELISA. The ELISA assay was performed as described in Example 2, using recombinant human EGFR protein (Acro Biosystems, Cat. No. EGR-H5222) and B7-H3 protein (Acro Biosystems, Cat. No. B73-H52E2) as the detection antigens, in which bispecific antibodies B035 and B036 were serially diluted from the initial highest concentration of 2 gg / mL. The ELISA results for binding to human EGFR are shown in Figure 8A, and the ELISA results for binding to human B7-H3 protein are shown in Figure 8B. Bispecific antibody B036 showed strong binding to EGFR, with an EC50 value of 15.65 ng / mL. Bispecific antibody B035 showed weaker binding to EGFR, with an EC50 value of 205.2 ng / mL. Bispecific antibodies B036 and B035 exhibited comparable binding to B7-H3, with EC50 values ranging from 1.5-2.2 ng / mL. BLI for determining the affinities of bispecific antibodies The purified B035 and B036 from Example 4 were determined for their binding affinities to EGFR and B7-H3 by BLI assay. The BLI assay was performed as described in Example 2. The BLI assay results are shown in Table 7. Bispecific antibody B035 had an affinity for EGFR of 4.29 x 10-8 M; bispecific antibody B036 had an affinity for EGFR of 4.74 x 10-9 M. This indicates that B035 had about 10-fold lower binding affinity for EGFR than B036. The affinity of bispecific antibody B036 for B7-H3 was between 2.75 x 10-12 M and 2.92 x 10-12 M. Table 7. Affinity Determination of Bispecific antibodies for EGFR and B7-H3 by BLI Antigen Antibody Name Kd (M) Kon(1 / Ms) Koff (1 / s) Human-EGFR B035 4.29E-08 8.15E+04 3.50E-03 Human-EGFR B036 4.74E-09 9.28E+04 4.40E-04 Human B7-H3(2Ig) B036 2.75E-12 2.75E+05 1.00E-07 Human B7-H3(4Ig) B036 2.92E-12 2.92E+05 1.00E-07 Example 6 Monitoring Bispecific Antibody Internalization Using Flow Cytometry Human pharyngeal squamous cell carcinoma FaDu cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, TCHu132), human lung adenocarcinoma NCI-H1975 cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, SCSP-597), human lung squamous carcinoma NCI-H226 cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, SCSP-5073), and human non-small cell lung cancer NCI-H1650 cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, SCSP-592), which endogenously express EGFR and B7-H3, were used as experimental models to evaluate the in vitro internalization effect of antibodies. Cell suspensions were prepared at a density of 2 x 106cells / mL using fresh serum-free MEM (Gibco, 11095-080) or 1640 (Gibco, 22400-089) cell culture medium. An antibody mixture was prepared with 2 gg / mL antibody and 4 ng / mL fluorescent antibody Alexa Fluor 647-affiniPure Fab Fragment Goat Anti-Human IgG (Jackson, 109-607-008) in serum-free medium. 200 liL of cells were mixed evenly with 200 liL of antibody mixture and incubated on ice for 30 minutes. After incubation, 100 LiL / well was added to cell culture plates. Binding wells were incubated on ice, and internalization wells were incubated at 37°C in the incubator with 5% CO2 for 1 hour and 2 hours, respectively. After washing, 200 LL of papain with a final concentration of 0.5 mg / mL was added to the internalization wells and incubated in the incubator for 15 minutes, at room temperature for 15 minutes. After incubation, cells were washed and resuspended in FACS buffer (PBS + 2% FBS), and were detected by Beckman flow cytometer. The experimental results showed that, in H1975 and FaDu tumor cell lines co-expressing EGFR and B7-H3, bispecific antibody B036 of the present invention exhibited greater internalization than the corresponding monospecific parental antibodies hzA001.8 and hz33D6.8. In addition, B036 exhibited greater internalization than the combination of the two monoclonal antibodies incubated together (Figures 9A and 9B). Similarly, in NCI-H226 and NCI-H1650 tumor cell lines co-expressing EGFR and B7-H3, bispecific antibody B035 of the present invention exhibited greater internalization than the corresponding monospecific parental antibodies hzA001.12 and hz33D6.8. In addition, B035 exhibited greater internalization than the combination of the two monoclonal antibodies incubated together (Figures 9C and 9D). Example 7 Preparation and Analysis of Antibody-Drug Conjugates Example 7.1 Synthesis of a Drug-Linker Intermediate Compound The drug-linker compounds used in this Example were synthesized, and the ADCs were prepared, according to the procedures described in the present applicant’s co-pending application WO2024 / 175069, which is incorporated herein by reference in its entirety. Specifically, the intermediate compounds LY22CD and LY22CD3 were synthesized as described in Examples 28 and 30, respectively, of WO2024 / 175069: Example 7.2 ADC Preparation and Characterization Preparation of Antibody-Drug Conjugate B035-LY22CD At 37°C, an aqueous solution of tris(2-carboxyethyl)phosphine (TCEP) (40mM, 23.3LL, 931nmol) was added to a PBS-buffered aqueous solution (0.01M PBS-buffered aqueous solution, pH=7.4) of bispecific antibody B035 (10.0 mg / mL, 2 mL, 133 nmol). The mixture was placed in a water bath and reacted at 37°C for 2 hours. The reaction was stopped. The reaction solution was cooled to room temperature in a water bath. Compound LY22CD (2.85mg, 1995nmol) was dissolved in 125LL DMSO and added to the above reaction solution. The mixture was placed in a water bath and reacted at 25°C for 30 minutes. The reaction solution was purified by dialysis using a Slide-A-Lyzer™ dialysis cassette (10K MWCO) to obtain the antibody-drug conjugate B035-LY22CD in histidine buffer (20mM histidine-HCl buffer, pH=5.5). It was stored at 4°C, and at -80°C for long-term storage. SEC-HPLC Analysis The monomer content of B035-LY22CD was determined to be 98.9% using the SEC-HPLC method. The SEC-HPLC experimental instrument was a Thermo Vanquish Core High Performance Liquid Chromatograph, and the chromatographic column was a Waters BioResolve SEC mAb (specifications: 2.5 Lim, 7.8 x 300 mm). Isocratic elution was performed using PBS-isopropanol (95:5) as the mobile phase. The elution time was 30 minutes, the flow rate was 0.5 mL / min, the detection wavelength was 280 nm, and the column temperature was 25 °C. The results are shown in Figure 10. DAR Determination The drug-to-antibody ratio (DAR) of B035-LY22CD was calculated by RP-HPLC measurement. The RP-HPLC instrument was an Agilent 1200 high-performance liquid chromatograph; the chromatographic column was a Thermo MAbPac RP (specifications: 4 Lm, 3 x 100 mm); mobile phase A (0.1% trifluoroacetic acid in water) and mobile phase B (acetonitrile / isopropanol / trifluoroacetic acid, 80:20:0.1) were used for gradient elution (0-28 min 30%B-50%B). The flow rate was 0.4 mL / min, the detection wavelength was 280 nm, and the column temperature was 70 °C. The results are shown in Figure 11. The calculated DAR value for B035-LY22CD was 7.86. Preparation and Analysis of Other ADCs Following a similar method to that described above, antibody-drug conjugates B035-LY22CD3 and B036-LY22CD were prepared by conjugating bispecific antibodies with the small molecule LY22CD3. The SEC purity and average drug-to-antibody ratio (DAR) of the conjugates were analyzed. The results are shown in Table 8 below. Table 8. SEC Purity and Average Drug-to-Antibody Ratio (DAR) of Antibody-Drug Conjugates Antibody-Drug Conjugate SEC Purity DAR Values B035-LY22CD 98.9% 7.86 B035-LY22CD3 97.1% 7.81 B036-LY22CD 97.2% 7.76 Following a similar method, conjugates of parental monospecific antibodies hzA001.8 and hz33D6.8 with compound LY22CD were prepared for use as controls in subsequent examples. Example 8: Determination of In Vitro Cell Activity of Antibody-Drug Conjugates In vitro activity assays of ADCs were performed using human pharyngeal squamous cell carcinoma FaDu cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, TCHu132) and human non-small cell lung squamous carcinoma NCI-H226 cells (Cell Bank of the Typical Culture Collection Committee of the Chinese Academy of Sciences, SCSP-5073). Cells were seeded in 96-well plates at 1000 cells / 100 nL for cell culture. Antibody-drug conjugates (ADCs), prepared by serial dilution (highest concentration 400 nM, 4-fold dilution, 9 concentrations), were added to the corresponding cell wells, mixed thoroughly, and cultured for 6 days at 37°C with 5% CO2. After co-incubation of the antibody-drug conjugates with cells for 6 days, pre-prepared CellTiter-Glo® Luminescent Cell Reagent (Promega, G7571) was added to the cell wells, incubated at room temperature in the dark for 3 minutes, and luminescence was detected using a microplate reader (Tecan, Spark). The half-maximal inhibitory concentration (IC50) was calculated using GraphPad Prism software. In human pharyngeal squamous cell carcinoma FaDu cells, the bispecific ADC B036-LY22CD exhibited significant cell-killing activity, with a maximum killing rate of 97.9% and an IC50 value of 5.25 nM. Its cell-52 killing activity was superior not only to that of the corresponding monospecific ADCs, hzA001.8-LY22CD and hz33D6.8-LY22CD, but also to that of the combination of hzA001.8-LY22CD and hz33D6.8-LY22CD (Figure 12A). In non-small cell lung squamous carcinoma NCI-H226 cells, the bispecific ADC B036-LY22CD exhibited certain cell-killing activity, with a maximum killing rate of about 90% and an IC50 value of about 90nM. Its cellkilling activity was superior not only to that of the corresponding monospecific ADCs, hzA001.8-LY22CD and hz33D6.8-LY22CD, but also to that of the combination of hzA001.8-LY22CD and hz33D6.8-LY22CD (Figure 12B). Example 9. In vivo Experiment in FaDu Cell Xenograft Mice CB17 SCID mice were purchased from Zhejiang Vitolihua Experimental Animal Technology Co., Ltd. FaDu cells were routinely passaged and cultured for the subsequent in vivo study. The cells were harvested by centrifugation and resuspended in a 1:1 mixture of RPMI-1640 medium and Matrigel Matrix (Corning) to obtain a cell suspension at a concentration of 5x107 cells / mL. A 0.1 mL aliquot of the cell suspension was subcutaneously inoculated into the right dorsal flank of each CB17 SCID mouse to establish a FaDu tumor-bearing mouse model. When the tumor volume reached 250-300 mm3, the animals were randomized into groups and administered a single dose of the respective ADCs by tail-vein injection. The treatment groups included mice receiving hzA001.8-LY22CD, hz33D6.8-LY22CD, hzA001.8-LY22CD + hz33D6.8-LY22CD, B035-LY22CD, or B036-LY22CD, each at a dose of 1.5 mg / kg, and mice receiving B036-LY22CD at a dose of 5 mg / kg. The control group received a PBS injection. Tumor volume and body weight of mice were monitored twice a week. The maximum long axis (L) and maximum short axis (W) of tumors were measured with a caliper, and tumor volume was calculated using the formula: V=L*W2 / 2. Body weight was measured using an electronic balance. Mice were euthanized when the mean tumor volume of a treatment group exceeded 2,000 mm3 or when body weight loss exceeded 20%. Tumor Growth Inhibition rate (%TGI) was calculated as: TGI% = (1-Ti / Ci) x 100; where Ti and Ci are the average tumor volumes of the treatment group and control group, respectively, at a specific time point. On day 20 post-dosing, the inhibition rates of each tested ADC drug are shown in Table 9. As shown in Figure 13A, all tested ADCs exhibited significant tumor growth inhibition in the FaDu xenograft tumors during the 60-day period following dosing. At a dose of 1.5 mg / kg, the tumor inhibitory effects of bispecific ADCs B035-LY22CD and B036-LY22CD were superior to the corresponding monospecific ADCs, hzA001.8-LY22CD and hz33D6.8-LY22CD, and also superior to the combination of monospecific ADCs (hzA001.8-LY22CD+hz33D6.8-LY22CD comb). Moreover, the tumor growth-inhibitory activity of the bispecific ADCs increased with increasing concentrations. Meanwhile, monitoring of mouse body weight showed no significant decrease in body weight during the 60-day period following dosing (Figure 13B). Table 9. Tumor Inhibition Effect in FaDu Xenograft Model Group Dosage Average Tumor Volume (mm3) Tumor Inhibition Rate (%) Complete Remission Rate* PBS - 2391.37 N / A 0 / 7 hzA001.8-LY22CD 1.5mg / kg 349.50 85 0 / 7 hz33D6.8-LY22CD 1.5mg / kg 921.48 61 0 / 7 hzA001.8-LY22CD + hz33D6.8-LY22CD 1.5mg / kg 311.48 87 0 / 7 B035-LY22CD 1.5mg / kg 33.35 99 1 / 7 B036-LY22CD 1.5mg / kg 70.61 97 2 / 7 B036-LY22CD 5mg / kg 18.62 99 1 / 7 *Complete remission rate: complete tumor regression, tumor volume is 0 Example 10: In vivo Experiment in NCI-H1650 Cell Xenograft Mice A subcutaneous xenograft model of human tumor cell line (NCI-H1650) was established in CB17 SCID mice according to the method of Example 9. When the tumor volume reached 150-250 mm3, a single tail vein injection was administered. The test substances B036-LY22CD, hzA001.8-LY22CD, hz33D6.8-LY22CD, hzA001.8-LY22CD+hz33D6.8-LY22CD, and B035-LY22CD were all administered at a dose of 3 mg / kg. Tumor volume and body weight of mice were monitored twice a week. The maximum long axis (L) and maximum short axis (W) of tumors were measured with a caliper, and tumor volume was calculated using the formula: V=L*W2 / 2. Body weight was measured using an electronic balance. Mice were euthanized when the mean tumor volume of a group exceeded 2,000 mm3 or when body weight loss exceeded 20%. Tumor Growth Inhibition rate (%TGI) was calculated as: TGI% = (1-Ti / Ci) x 100; where Ti and Ci are the average tumor volumes of the treatment group and control group, respectively, at a specific time point. On day 25 post-dosing, the inhibition rates of each tested ADC drug are shown in Table 10. As shown in Figure 14A, all tested ADCs exhibited significant tumor growth inhibition in the NCI-H1650 xenograft tumors during the 48-day period following dosing. At a dose of 3 mg / kg, the tumor inhibitory effects of bispecific ADCs B035-LY22CD and B036-LY22CD were superior to the monospecific ADCs, hzA001.8-LY22CD and hz33D6.8-LY22CD, and also superior to the combination of monospecific ADCs (hzA001.8-LY22CD+hz33D6.8-LY22CD comb). Meanwhile, monitoring of mouse body weight showed no significant decrease in body weight during the 48-day period following dosing (Figure 14B). Table 10. Tumor Inhibition Effect in NCI-H1650 Xenograft Model Group Dosage Average Tumor Volume (mm3) Tumor   Inhibition Rate (%) Complete Remission Rate* PBS - 2554.37 N / A 0 / 7 B036-LY22CD 3 mg / kg 8.71 100 1 / 7 hzA001.8-LY22CD 3 mg / kg 250.98 90 0 / 7 hz33D6.8-LY22CD 3 mg / kg 302.97 88 0 / 7 hzA001.8-LY22CD + hz33D6.8-LY22CD 3 mg / kg 126.10 95 0 / 7 B035-LY22CD 3 mg / kg 14.97 99 0 / 7 *Complete remission rate: complete tumor regression, tumor volume is 0 Example 11: In vivo Experiment in NCI-H1975 Cell Xenograft Mice A subcutaneous xenograft model of human tumor cell line (NCI-H1975) was established in CB17 SCID mice according to the method of Example 9. When the tumor volume reached 150-300 mm3, a single tail vein injection was administered. The test substances B035-LY22CD3, B043-BYBL, B043-LY22CD, and B035-LY22CD were all administered at a dose of 10 mg / kg. The control antibody B043 used in this Example was prepared according to the method described in Chinese Patent No. CN106659779B (B043 corresponds to the anti-EGFR / HER3 bispecific antibody designated “SI-1X6.4” in the document.) The bispecific ADC B043-BYBL was prepared according to the method described in Patent Application Publication No. WO2023083381A1 (B043-BYBL corresponds to “ADC-6” in the document; the BL-B01D1 drug product form of this ADC is currently in clinical trials; see The Lancet Oncology, Vol. 25, No. 7, DOI: 10.1016 / S1470-2045(24)00159-1). Tumor volume and body weight of mice were monitored twice a week. The maximum long axis (L) and maximum short axis (W) of tumors were measured with a caliper, and tumor volume was calculated using the formula: V=L*W2 / 2. Body weight was measured using an electronic balance. Mice were euthanized when the mean tumor volume of a group exceeded 2,000 mm3 or when body weight loss exceeded 20%. Tumor Growth Inhibition rate (%TGI) was calculated as: TGI% = (1-Ti / Ci) x 100; where Ti and Ci are the average tumor volumes of the treatment group and control group, respectively, at a specific time point. On day 24 post-dosing, the inhibition rates of each tested ADC drug are shown in Table 11. As shown in Figure 15A, all tested ADCs exhibited significant tumor growth inhibition in the NCI-H1975 xenograft tumors during the 40-day period following dosing. At a dose of 10 mg / kg, the anti-tumor effects of bispecific ADCs B035-LY22CD and B035-LY22CD3 were similar and significantly superior to B043-BYBL and B043-LY22CD. Meanwhile, monitoring of mouse body weight showed no significant decrease in body weight during the 40-day period following dosing (Figure 15B). Table 11. Tumor Inhibition Effect in NCI-H1975 Xenograft Model Group Average Tumor Volume (mm3) Tumor Inhibition Rate (%) Complete Remission Rate* PBS 2056.77 N / A 0 / 6 B035-LY22CD 87.56 96 0 / 6 B035-LY22CD3 63.43 97 0 / 6 B043-BYBL 240.99 88 0 / 6 B043-LY22CD 308.57 85 0 / 6 *Complete remission rate: complete tumor regression, tumor volume is 0 Example 12 In vivo Pharmacodynamic Study in Tumor Patient-Derived Xenograft (PDX) Models Mouse PDX studies were conducted at Crown Bioscience (Beijing) Inc. Tumor tissues were harvested from tumor-bearing mice in the HuPrime® lung cancer xenograft model, cut into 2-3 mm diameter fragments, and subcutaneously implanted into the right anterior shoulder region of BALB / c nude mice. Before dosing, all animals were weighed, and tumor volumes were measured using calipers. When the mean tumor volume reached the appropriate starting tumor volume range (170-200 mm3), the animals were randomized into groups based on tumor volume and administered. According to the experimental design, dosing in the LU0894 model was initiated on the day of randomization (Day 0), whereas dosing in the other eight lung cancer models was initiated on the day after randomization (Day 1). The animals in all the groups received a single intravenous dose of 10 mg / kg. Following tumor cell implantation, tumor growth and the effects of treatment on the normal behavior of the animals were routinely monitored, including activity, food and water intake, body weight gain or loss, eye and fur condition, and other abnormalities of the experimental animals. After initiation of dosing, body weight and tumor size of mice were measured twice weekly. Figure 16 presents the changes in relative tumor volume following treatment with B035-LY22CD3 across the different PDX models, ranked by antitumor efficacy. Based on tumor volume measurements obtained 14-28 days after dosing, the bispecific ADC B035-LY22CD3 induced tumor growth inhibition or regression in a multiple of tested PDX models. Partial remission (PR) was observed in the LU0357, LU0377, LU2512, LU1204, and LU0894 PDX models, whereas stable disease (SD) was observed in the LU11554, LU6437, LU0350, and LU1219 PDX models, resulting in an overall disease control rate of 100%. Example 13: In vivo pharmacodynamic study in tumor patient-derived xenograft (PDX) models In vivo pharmacodynamic studies in mouse PDX models were conducted at Crown Bioscience (Beijing) Inc., Shanghai Lide Biotechnology Co., Ltd., and Suzhou Wuxi AppTec Co., Ltd. The experimental models included EGFR wild-type or mutant non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), breast cancer, head and neck squamous cell carcinoma (HNSCC), and small cell lung cancer (SCLC). Tumor tissues were harvested from tumor-bearing mice in the PDX xenograft model, cut into about 3 mm diameter fragments, and subcutaneously implanted into the right hind flank region of immunodeficient mice. Before dosing, all animals were weighed, and tumor volumes were measured using calipers. When the mean tumor volume reached the appropriate starting tumor volume range (140-200 mm3), the animals were randomized into groups based on tumor volume and administered. The day of randomization was set as Day 0. According to the experimental design, dosing in all the models was initiated on Day 0 or Day 1. The animals in all the groups received a single intravenous dose of 10 mg / kg. Following tumor cell implantation, tumor growth and the effects of treatment on the normal behavior of the animals were routinely monitored, including activity, food and water intake, body weight gain or loss, eye and fur condition, and other abnormalities of the experimental animals. After initiation of dosing, body weight and tumor size of mice were measured twice weekly. Figure 17 presents the changes in relative tumor volume following administration of B035-LY22CD3 across the different PDX models, ranked by antitumor efficacy. As the results show, based on measurements obtained 1428 days after dosing, the bispecific ADC B035-LY22CD3 induced tumor growth inhibition or regression in a multiple of tested PDX models. Among 26 PDX models, 46% models showed tumor complete response (CR), 35% showed partial remission (PR), and 19% showed stable disease (SD), resulting in an overall disease control rate (DCR) of 100% (Table 12). Table 12: Summary of Efficacy of B035-LY22CD3 in Different PDX Models Cancer Type CR PR SD DCR Non-Small Cell Lung Cancer (EGFR Wild Type) 4 1 4 9 Non-Small Cell Lung Cancer (EGFR Mutant) 1 1 0 2 Esophageal Squamous Cell Carcinoma 1 2 1 4 Breast Cancer 3 1 0 4 Head and Neck Squamous Cell Carcinoma 1 3 0 4 Small Cell Lung Cancer 2 1 0 3 Total 12 9 5 26 Percentage 46% 35% 19% 100% Example 14: Pharmacokinetics of Bispecific ADC in Cynomolgus Monkeys Toxicology and pharmacokinetic studies were conducted in cynomolgus monkeys at Jiangsu Dingtai Biotechnology Co., Ltd. Cynomolgus monkeys aged 3-5 years were randomly assigned to groups and administered a single intravenous bolus dose of 15 mg / kg B035-LY22CD3 or B036-LY22CD. Blood samples (approximately 0.25 mL per time point) were collected before dosing (0 min) and at 1, 3, 8, 24, 72, 168, 240, and 336 h after dosing. Samples were transferred into pre-chilled EDTA-K2 tubes and maintained on wet ice until centrifugation. After centrifugation, plasma samples were collected and snap-frozen on dry ice until analysis by ELISA. Total Antibody ELISA. 96-well microtiter plates were coated with EGFR (ACRO Biosystems, EGR-H5222) and B7-H3 (ACRO Biosystems, B73-H52E2) and incubated overnight at 4°C. The coating solution was discarded, and 300 liL of 3% BSA in PBST solution was added to block the wells for 2 hours at room temperature. After washing three times with PBST, serum samples collected at different time points were diluted to a certain gradient, and added to the wells at 100 lL / well. A gradient of an ADC reference standard was established (ADC reference standard, starting concentration of 50 ng / mL, 2-fold serial dilutions). The plates were incubated at 37°C for 1 h. After washing three times with PBST, 100 lL of HRP-conjugated goat anti-human IgG antibody (Southern Biotech, Cat. No. 2049-05; 1:5,000 dilution) was added, followed by incubation at 37°C for 0.5 h. The plates were washed three times with PBST, after which 100 lL of TMB substrate was added for color development for 10 min. The reaction was terminated by addition of 100 lL of 2 M sulfuric acid, and absorbance at 450 nm was measured using a multimode microplate reader (Tecan, Spark). ADC ELISA. 96-well microtiter plates were coated with EGFR (ACRO Biosystems, EGR-H5222) and B7-H3 (ACRO Biosystems, B73-H52E2) and incubated overnight at 4°C. The coating solution was discarded, and 300 lL of 3% BSA in PBST solution was added to block the wells for 2 hours at room temperature. After washing three times with PBST, serum samples collected at different time points were diluted to a certain gradient, and added to the wells at 100 lL / well. A gradient of a reference standard was established (ADC reference standard, starting concentration of 50 ng / mL, 2-fold serial dilutions). The plates were incubated at 37°C for 1 h. After washing three times with PBST, 100 lL of anti-Payload antibody (in-house produced, 19E9F1H7) at a final concentration of 1 lg / mL was added and incubated for 1 hour at 37°C. After washing three times with PBST, 100 lL of HRP-labeled goat anti-mouse IgG (Jackson ImmunoResearch, 115-035-071, 1:5000 dilution) was added and incubated for 0.5 hours at 37°C. The plates were washed three times with PBST, and 100 lL of TMB substrate was added for color development for 10 min. The reaction was terminated by addition of 100 lL of 2 M sulfuric acid, and absorbance at 450 nm was measured using a multimode microplate reader (Tecan, Spark). The results (Figure 18A and Figure 18B) indicate that after intravenous bolus injection of the samples (15 mg / kg) into cynomolgus monkeys, the plasma concentrations of total antibody and ADC reached peak levels at about 1 h, followed by a gradual decrease in drug concentration. Calculation of the terminal half-life (T1 / 2) showed that B035-LY22CD3 exhibited higher drug exposure and a longer half-life in cynomolgus monkeys (Table 13). Compared to B036-LY22CD, B035-LY22CD3 demonstrated better PK stability. Table 13. Half-life Results of B035-LY22CD3 and B036-LY22CD in PK Experiments ADC Parameter Total Ab (B7-H3) ADC (B7-H3) Total Ab (EGFR) ADC (EGFR) B035-LY22CD3 T1 / 2(h) 87.47 81.01 79.90 70.54 B036-LY22CD T1 / 2 (h) 49.10 48.03 46.42 52.22 Example 15: Preliminary Toxicology Study of B035-LY22CD3 in Primate Non-GLP toxicology studies in Primate were conducted at WuXi AppTec Co., Ltd., Suzhou. A total of six cynomolgus monkeys were randomly assigned to three groups (two animals per group comprising one male and one female), receiving B035-LY22CD3 at a low dose (10 mg / kg), a mid-dose (30 mg / kg), and a high dose (60 mg / kg), respectively. Dosing occurred on Day 1, Day 22, and Day 43, for a total of 3 administrations. Throughout the study, all dosed cynomolgus monkeys tolerated the treatment well. Body weight and food consumption remained normal, and no gastrointestinal adverse effects were observed. The body weight change 57 curves in cynomolgus monkeys are shown in Figure 19. These results indicated that B035-LY22CD3 exhibited a favorable safety profile. The highest non-severely toxic dose (HNSTD) of B035-LY22CD3 was determined to be >30 mg / kg. Sequence Description SEQ ID NO: Sequence Name Sequence Murine B7-H3 antibody variable region sequences 1 33D6 VH EVQLVESGGGLVKPGGSLKLSCAASGFTFSSSAMSWVRQTPEKRLEW VATINSGGIYTYYPDSVKGRFTISRDNVKNTLYLQMNNLRSEDTAMY YCARHADYRAGFPYWGQGTLVTVSA 2 33D6 VL DIQMTQSPASLSVSVGETVTITCRASENIHSNLAWYQQKQGKSPQLLV YTATNLADGVPSRFSGSGSGTQYSLKINSLQSEDFGTYYCQRFWGPT WTFGGGTKLEIK Humanized B7-H3 antibody variable region sequences 3 hz33D6.8 VH EVQLLESGGGLVQPGGSLRLSCAASGFTFSSSAMSWVRQAPGKGLEW VATINSGGIYTYYPDSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYY CARHADYRAGFPYWGQGTLVTVSS 4 hz33D6.8 VL DIQMTQSPSSLSASVGDRVTITCRASENIHSNLAWYQQKPGKAPKLLV YTATNLESGVPSRFSGSGSGTDYTLTISSLQPEDFATYYCQRFWGPTW TFGGGTKVEIK Humanized B7-H3 antibody CDR sequences, as defined by Kabat scheme 5 hz33D6.8-LCDR1 RASENIHSNLA 6 hz33D6.8-LCDR2 TATNLES 7 hz33D6.8-LCDR3 QRFWGPTWT 8 hz33D6.8-HCDR1 SSAMS 9 hz33D6.8-HCDR2 TINSGGIYTYYPDSVKG 10 hz33D6.8-HCDR3 HADYRAGFPY Murine EGFR antibody variable region sequences 11 A001 VH QVQLKESGPGLVAPSQSLSITCTVSGFSLTTYGVHWVRQPPGKGLEW LGVIWAGGSTNYNSALMSRLSIKKDNSKSQVFLKMNSLQTDDTAMY YCARAYGYNFDYWGQGTTLTVSS 12 A001 VL DIQMTQTTSSLSASLGDRVTISCSASQGITNYLNWYQQKPDGTVKLLI YYSSSLHSGVPSRFSGSGSGTDYSLTISNLEPEDIATYYCQQYSEIPYTF GGGTKLELK Humanized EGFR antibody variable region sequences 13 hzA001.8 VH QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDNSKNQVSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSS 14 hzA001.8 VL DIQMTQSPSSLSASVGDRVTITCSASQGITNYLNWYQQKPGKAPKLLI YYSSSLHSGVPSRFSGSGSGTDYTLTISSLQPEDFATYYCQQYSEIPYTF GGGTKVEIK 15 hzA001.12 VH QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDTSKNQFSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSS 16 hzA001.12 VL DIQMTQSPSSLSASVGDRVTITCSASQGITNYLNWYQQKPGKAPKLLI YYSSSLHSGVPSRFSGSGSGTDYTLTISSLQPEDFATYYCQQYSEIPYTF GGGTKVEIK Humanized EGFR antibody CDR sequences, as defined by Kabat scheme; Two humanized antibodies, hzA001.8 and hzA001.12, have identical CDR sequences. 17 LCDR1 SASQGITNYLN 18 LCDR2 YSSSLHS 19 LCDR3 QQYSEIPYT 20 HCDR1 TYGVH 21 HCDR2 VIWAGGSTNYNSALES 22 HCDR3 AYGYNFDY B7-H3 half-antibody light chain and heavy chain sequences 23 Light chain hz33D6.8-H18-L DIQMTQSPSSLSASVGDRVTITCRASENIHSNLAWYQQKPGKAPKLLV YTATNLESGVPSRFSGSGSGTDYTLTISSLQPEDFATYYCQRFWGPTW TFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAK VQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKV YACEVTHQGLSSPVTKSFNRGEC 24 Heavy chain hz33D6.8-H18-H, with Hole mutations EVQLLESGGGLVQPGGSLRLSCAASGFTFSSSAMSWVRQAPGKGLEW VATINSGGIYTYYPDSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYY CARHADYRAGFPYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTA ALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVT VPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKA LPAPIEKTISKAKGQPREPQVYTYPPSREEMTKNQVSLSCAVKGFYPS DIAVEWESNGQPENNYKTTPPVLRSDGSFFLVSKLTVDKSRWQQGNV FSCSVMHEALHNHYTQKSLSLSPG 54 Heavy chain hz33D6.8-H18-H, with Hole mutations, having C-terminal K residue EVQLLESGGGLVQPGGSLRLSCAASGFTFSSSAMSWVRQAPGKGLEW VATINSGGIYTYYPDSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYY CARHADYRAGFPYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTA ALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVT VPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELL GGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGV EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKA LPAPIEKTISKAKGQPREPQVYTYPPSREEMTKNQVSLSCAVKGFYPS DIAVEWESNGQPENNYKTTPPVLRSDGSFFLVSKLTVDKSRWQQGNV FSCSVMHEALHNHYTQKSLSLSPGK EGFR half-antibody light chain and heavy chain sequences 25 Light chain hzA001.12-K26-L and hzA001.8-K26-L DIQMTQSPSSLSASVGDRVTITCSASQGITNYLNWYQQKPGKAPKLLI YYSSSLHSGVPSRFSGSGSGTDYTLTISSLQPEDFATYYCQQYSEIPYTF GGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKV QWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVY ACEVTHQGLSSPVTKSFNRGEC 26 Heavy chain hzA001.12-K26-H, With Knob mutations QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDTSKNQFSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALG CLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS SLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPI EKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLWCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSDLTVDKSRWQEGNVFSCSV MHEALHNHYTQKSLSLSPG 55 Heavy chain hzA001.12-K26-H, With Knob mutations having C-terminal K residue QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDTSKNQFSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALG CLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS SLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPI EKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLWCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSDLTVDKSRWQEGNVFSCSV MHEALHNHYTQKSLSLSPGK 27 Heavy chain hzA001.8-K26-H With Knob mutations QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDNSKNQVSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALG CLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS SLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPI EKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLWCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSDLTVDKSRWQEGNVFSCSV MHEALHNHYTQKSLSLSPG 56 Heavy chain hzA001.8-K26-H With Knob mutations having C-terminal K residue QVQLQESGPGLVKPSETLSLTCTVSGFSLTTYGVHWIRQPPGKGLEWI GVIWAGGSTNYNSALESRVTISKDNSKNQVSLKLSSVTAADTAVYYC ARAYGYNFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALG CLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSS SLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPS VFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPI EKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLWCLVKGFYPSDIAVE WESNGQPENNYKTTPPVLDSDGSFFLYSDLTVDKSRWQEGNVFSCSV MHEALHNHYTQKSLSLSPGK Other Antibody Components 28 Human IgG1 Constant Region Hole chain ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDK KVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTV LHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTYPPSR EEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLRSDG SFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPG 29 Human IgG1_Fc Hole chain EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVV DVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLH QDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTYPPSREE MTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLRSDGSF FLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPG 30 Human IgG1 Constant Region Knob Chain ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDK KVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTV LHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSQ EEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSD GSFFLYSDLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSPG 31 Human IgG1_Fc Knob Chain EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVV DVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLH QDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSQEE MTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSF FLYSDLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSPG 32 Human IgG1_CH1 domain ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDK KV 33 Human kappa Light chain Constant Region RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNAL QSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGL SSPVTKSFNRGEC 52 Human IgG1 Constant ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS Region Hole Chain, having C-terminal K residue GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDK KVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTV LHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTYPPSR EEMTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLRSDG SFFLVSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 53 Human IgG1 Constant Region Knob Chain, having C-terminal K residue ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDK KVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCV VVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTV LHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSQ EEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSD GSFFLYSDLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSPGK Murine 33D6 antibody CDR sequence, as defined by Kabat scheme; the other CDR sequences are the same as its humanized version. 34 33D6-LCDR2 TATNLAD Murine EGFR antibody CDR sequence, as defined by Kabat scheme; the other CDR sequences are the same as its humanized version. 35 A001-HCDR2 VIWAGGSTNYNSALMS Murine B7-H3 antibody variable region sequences 36 32F8 VH QVQLQQSGPELLKPGASVKMSCQTSGYTFTDYVITWVKQRTGQGLEWIG EIYPRSDRTYYNENFKGKATLTADKSSNTAYMQLSSLTSEDSAVYFCARWD NYYFDYWGQGTTLTVSS 37 32F8 VL DVVMTQTPLSLPVSLGDQASISCRSGQSLVHSNGITYLHWYLQKPGQSPK LLIYKVSNRFSGVPDRFSGSGSGTDFTLKISRVEAEDLGVYFCSQTTHVPW TFGGGTKLEIK 38 3H3 VH QVTLKESGPGKLQPSQTLSLTCSFSGFSLSTSGMGVSWIRQPSGKG LDWLAHIYWDEDKRYNPSLKSRLTISKDPSGNQVFLRITSVDTADT ATYYCARAFYGNMDYWGQGTSVVVSS 39 3H3 VL DIQLTQTTSSLSASLGDRVTITCRSSQDIINYLNWYQQKPNGTIKLLI SYSSRLHSGVPSRFSGGGSRSDYSLTISDLEQEDIATYFCQQGKTLP FTFGSGTKLEIK 40 32F8-LCDR1 RSGQSLVHSNGITYLH 41 32F8-LCDR2 KVSNRFS 42 32F8-LCDR3 SQTTHVPWT 43 32F8-HCDR1 DYVIT 44 32F8-HCDR2 EIYPRSDRTYYNENFKG 45 32F8-HCDR3 WDNYYFDY 46 3H3-LCDR1 RSSQDIINYLN 47 3H3-LCDR2 YSSRLHS 48 3H3-LCDR3 QQGKTLPFT 49 3H3-HCDR1 TSGMGVS 50 3H3-HCDR2 HIYWDEDKRYNPSLKS 51 3H3-HCDR3 AFYGNMDY Other sequences 57 Peptide linker (G4S)n (GGGGS)n, where n is an integer equal to or greater than 1 58 Peptide linker TS(G4S)n TS(GGGGS)n, where n is an integer equal to or greater than 1 59 Peptide linker G(GGGGS)n, where n is an integer equal to or greater than 1 G(G4S)n 60 Peptide linker (G4)n (GGGG)n, where n is an integer equal to or greater than 1 61 Peptide linker (GRPGS)n (GRPGS)n, where n is an integer equal to or greater than 1 62 Oligopeptide GFLG, = Gly-Phe-Leu-Gly 63 Oligopeptide ALAL, =Ala-Leu-Ala-Leu 64 Oligopeptide GGFG, =Gly-Gly-Phe-Gly 65 Oligopeptide KGVA, =Lys-Gly-Val-Ala 66 Oligopeptide KGVX, wherein X is Cit, =Lys-Gly-Val-Cit 67 Oligopeptide KGGVA, =Lys-Gly-Gly-Val-Ala 68 Oligopeptide KGGVX, wherein X is Cit, =Lys-Gly-Gly-Val-Cit 69 Oligopeptide KQVX, wherein X is Cit, =Lys-Gln-Val-Cit 70 Oligopeptide KQVA, =Lys-Gln-Val-Ala 71 Oligopeptide KEVX, wherein X is Cit, =Lys-Glu-Val-Cit 72 Oligopeptide KEVA , =Lys-Glu-Val-Ala 73 Oligopeptide KDVX, wherein X is Cit, =Lys-Asp-Val-Cit 74 Oligopeptide KDVA , =Lys-Asp-Val-Ala

Claims

1. An antibody that specifically binds to B7-H3 and EGFR, comprising a first antigen-binding domain that specifically binds to B7-H3 and a second antigen-binding domain that specifically binds to EGFR, wherein the B7-H3 antigen-binding domain comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) contained within a heavy chain variable region (VH) and light chain variable region (VL) sequence pair selected from:(a) the VH sequence as shown in SEQ ID NO: 1 and the VL sequence as shown in SEQ ID NO: 2;(b) the VH sequence as shown in SEQ ID NO: 3 and the VL sequence as shown in SEQ ID NO: 4;(c) the VH sequence as shown in SEQ ID NO: 36 and the VL sequence as shown in SEQ ID NO: 37; and(d) the VH sequence as shown in SEQ ID NO: 38 and the VL sequence as shown in SEQ ID NO: 39.

2. The antibody according to claim 1, wherein the B7-H3 antigen-binding domain comprises a combination of HCDR1, HCDR2, and HCDR3 amino acid sequences and LCDR1, LCDR2, and LCDR3 amino acid sequences selected from: (a) SEQ ID NOs: 8, 9, 10, 5, 6, and 7; (b) SEQ ID NOs: 8, 9, 10, 5, 34, and 7; (c) SEQ ID NOs: 43, 44, 45, 40, 41, and 42; and (d) SEQ ID NOs: 49, 50, 51, 46, 47, and 48;preferably wherein:- HCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 8;- HCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 9;- HCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 10;- LCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 5;- LCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 6 or 34;- LCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 7;more preferably, the HCDR1, HCDR2, and HCDR3 respectively comprise or consist of the amino acid sequences as shown in SEQ ID NOs: 8-10; and the LCDR1, LCDR2, and LCDR3 respectively comprise or consist of the amino acid sequences as shown in SEQ ID NOs: 5-7.

3. The antibody according to claim 1 or 2, wherein the B7-H3 antigen-binding domain comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein:(i) the VH comprises, or consists of, an amino acid sequence selected from SEQ ID NOs: 1, 3, 36 and 38, or an amino acid sequence having at least 85%, 90%, 95% or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions and / or substitutions relative thereto; and / or(ii) the VL comprises, or consists of, an amino acid sequence selected from SEQ ID NOs: 2, 4, 37 and 39, or an amino acid sequence having at least 85%, 90%, 95% or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions and / or substitutions relative thereto;preferably, the VH and VL respectively comprise the amino acid sequences of SEQ ID NO: 3 and SEQ ID NO: 4, or amino acid sequences having at least 90%, 95% or 99% identity thereto, or amino acid sequences comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions and / or substitutions relative thereto;more preferably, the B7-H3 antigen-binding domain comprises a heavy chain variable region having the amino acid sequence as shown in SEQ ID NO: 3 and a light chain variable region having the amino acid sequence as shown in SEQ ID NO: 4.

4. The antibody of any one of claims 1-3, wherein the B7-H3 antigen-binding domain has one or more properties selected from the group consisting of:(a) binding to human B7-H3 with an affinity KD value of less than 1x10-10 M, optionally from about 5x10-11 M to 0.5x10-12 M, preferably about 1-5 x10-12 M;(b) binding to human B7-H3 with a dissociation rate constant Koff value of less than 1x10-5 s-1, optionallyfrom about 1x10-6 s-1 to 1x10-8 s-1, preferably about 0.5-5 x10-7 s-1; and(c) exhibiting immunological cross-reactivity with monkey B7-H3.

5. The antibody of any one of claims 1-4, wherein the antibody has one or more properties selected from the group consisting of:(a) the EGFR antigen-binding domain binds to human EGFR antigen with an affinity KD value of greater than 1x10-10M, preferably from 1x10-7M to 1x10-9M, optionally 1-6x10-8M or 1-6x10-9M;(b) the valency ratio of the B7-H3 antigen-binding domain to the EGFR antigen-binding domain in the antibody is 1:1;(c) the antibody is a bispecific antibody comprising an antigen-binding domain that specifically binds to B7-H3 and an antigen-binding domain that specifically binds to EGFR; and(d) the antibody is a bivalent bispecific antibody.

6. The antibody of any one of claims 1-5, wherein the antibody comprises an Fc dimer having a first immunoglobulin Fc region and a second immunoglobulin Fc region, and optionally wherein:(i) the first Fc region and the second Fc region are of IgG isotype,(ii) the first Fc region and the second Fc region are of IgG1 or IgG4 isotype, particularly human IgG1 or IgG4 isotype;(iii) the first Fc region and the second Fc region comprise amino acid mutations that promote the formation of the Fc dimer,(iv) the first Fc region comprises T366S-L368A-Y407V-L351Y-D399R, and the second Fc region comprises T366W-K409D-R355Q-Q419E, and / or(v) the first and second Fc regions respectively comprise the amino acid sequences of SEQ ID NO:29 and SEQ ID NO:31, or amino acid sequences at least 95%, 96%, 98% or 99% identical thereto.

7. The antibody of any one of claims 1-6, wherein the antibody comprises:- a first structural moiety comprising, from N-terminus to C-terminus, a first antigen-binding domain and a first immunoglobulin Fc region; and- a second structural moiety comprising, from N-terminus to C-terminus, a second antigen-binding domain and a second immunoglobulin Fc region;wherein the first and second immunoglobulin Fc regions dimerize to form an Fc dimer,wherein the first and second antigen-binding domains bind different antigens selected from B7-H3 and EGFR,preferably, wherein the first antigen-binding domain binds B7-H3 and comprises or consists of a Fab, scFab, or scFv domain; and / or wherein the second antigen-binding domain binds EGFR and comprises or consists of a Fab, scFab, scFv, or VHH domain,more preferably, the antibody is a bispecific antibody having a structure shown in Figure 1, wherein optionally the heavy chain containing the hole mutation and the heavy chain containing the knob mutation comprise the heavy chain constant regions of SEQ ID NO: 28 and SEQ ID NO: 30, respectively, or comprise the heavy chain constant regions of SEQ ID NO: 52 and SEQ ID NO: 53, respectively.

8. The antibody of any one of claims 1-7, wherein the antibody comprises an EGFR antigen-binding domain, and the EGFR antigen-binding domain comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) contained within a heavy chain variable region (VH) and light chain variable region (VL) sequence pair selected from:(a) the VH sequence as shown in SEQ ID NO: 11 and the VL sequence as shown in SEQ ID NO: 12;(b) the VH sequence as shown in SEQ ID NO: 13 and the VL sequence as shown in SEQ ID NO: 14; and(c) the VH sequence as shown in SEQ ID NO: 15 and the VL sequence as shown in SEQ ID NO: 16, preferably, wherein:- HCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 20;- HCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 21 or 35;- HCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 22;- LCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 17;- LCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 18;- LCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 19,more preferably, the HCDR1, HCDR2, and HCDR3 respectively comprise or consist of the amino acid sequences as shown in SEQ ID NOs: 20-22, and the LCDR1, LCDR2, and LCDR3 respectively comprise or consist of the amino acid sequences as shown in SEQ ID NOs: 17-19,still more preferably, the EGFR antigen-binding domain comprises:(i) a heavy chain variable region (VH), wherein the VH comprises or consists of an amino acid sequence selected from SEQ ID NOs: 11, 13, and 15, or an amino acid sequence having at least 85%, 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto; and / or(ii) a light chain variable region (VL), wherein the VL comprises or consists of an amino acid sequence selected from SEQ ID NOs: 12, 14, and 16, or an amino acid sequence having at least 85%, 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto,still more preferably, the EGFR antigen-binding domain comprises a heavy chain variable region and a light chain variable region, wherein the VH and VL respectively comprise or consist of the following amino acid sequences:(i) the amino acid sequences of SEQ ID NO: 11 and SEQ ID NO: 12, or amino acid sequences having at least 90%, 95%, or 99% identity thereto, or amino acid sequences comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;(ii) the amino acid sequences of SEQ ID NO: 13 and SEQ ID NO: 14, or amino acid sequences having at least 90%, 95%, or 99% identity thereto, or amino acid sequences comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto; or(iii) the amino acid sequences of SEQ ID NO: 15 and SEQ ID NO: 16, or amino acid sequences having at least 90%, 95%, or 99% identity thereto, or amino acid sequences comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto,most preferably, the EGFR antigen-binding domain comprises a heavy chain variable region and a light chain variable region, wherein the VH and VL comprise or consist of the amino acid sequences of SEQ ID NO: 13 and SEQ ID NO: 14, respectively; or the VH and VL comprise or consist of the amino acid sequences of SEQ ID NO: 15 and SEQ ID NO: 16, respectively.

9. The antibody of any one of claims 1-8, wherein the antibody comprises a first heavy chain, a first light chain, a second heavy chain and a second light chain, wherein the first heavy chain and the first light chain are paired and specifically bind B7-H3, and the second heavy chain and the second light chain are paired and specifically bind EGFR, andwherein the first heavy chain, the first light chain, the second heavy chain, and the second light chain respectively comprise or consist of the following amino acid sequences:(i) the first heavy chain comprises or consists of the amino acid sequence of SEQ ID NO: 24 or 54, or an amino acid sequence having at least 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;(ii) the first light chain comprises or consists of the amino acid sequence of SEQ ID NO: 23, or an amino acid sequence having at least 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;(iii) the second heavy chain comprises or consists of the amino acid sequence of SEQ ID NO: 26, 27, 55 or 56, or an amino acid sequence having at least 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;(iv) the second light chain comprises or consists of the amino acid sequence of SEQ ID NO: 25, or an amino acid sequence having at least 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one ormore (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto.

10. The antibody of any one of claims 1-9, wherein the antibody comprises a first heavy chain, a first light chain, a second heavy chain, and a second light chain, and wherein- the first heavy chain, first light chain, second heavy chain, and second light chain respectively comprise or consist of the amino acid sequences of SEQ ID NOs: 24, 23, 26, and 25;- the first heavy chain, first light chain, second heavy chain, and second light chain respectively comprise or consist of the amino acid sequences of SEQ ID NOs: 54, 23, 55, and 25;- the first heavy chain, first light chain, second heavy chain, and second light chain respectively comprise or consist of the amino acid sequences of SEQ ID NOs: 24, 23, 27, and 25; or- the first heavy chain, first light chain, second heavy chain, and second light chain respectively comprise or consist of the amino acid sequences of SEQ ID NOs: 54, 23, 56, and 25.

11. An anti-B7-H3 antibody comprising three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3) contained within a heavy chain variable region (VH) and light chain variable region (VL) sequence pair selected from SEQ ID NOs: 1 / 2, SEQ ID NOs: 3 / 4, SEQ ID NOs: 36 / 37, and SEQ ID NOs: 38 / 39,optionally, the anti-B7-H3 antibody comprises a combination of amino acid sequences of HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3 selected from: (a) SEQ ID NOs: 8, 9, 10, 5, 6, and 7; (b) SEQ ID NOs: 8, 9, 10, 5, 34, and 7; (c) SEQ ID NOs: 43, 44, 45, 40, 41, and 42; and (d) SEQ ID NOs: 49, 50, 51, 46, 47, and 48;preferably, wherein:- HCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 8;- HCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 9;- HCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 10;- LCDR1 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 5;- LCDR2 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 6 or 34;- LCDR3 comprises or consists of the amino acid sequence as shown in SEQ ID NO: 7,more preferably, the HCDR1, HCDR2, and HCDR3 and the LCDR1, LCDR2, and LCDR3 comprise or consist of the amino acid sequences as shown in SEQ ID NOs: 8-10 and SEQ ID NOs: 5-7, respectively,optionally, the B7-H3 antibody comprises:(i) a heavy chain variable region (VH), wherein the VH comprises or consists of an amino acid sequence selected from SEQ ID NOs: 1, 3, 36, and 38, or an amino acid sequence having at least 85%, 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto; and / or(ii) a light chain variable region (VL), wherein the VL comprises or consists of an amino acid sequence selected from SEQ ID NOs: 2, 4, 37, and 39, or an amino acid sequence having at least 85%, 90%, 95%, or 99% identity thereto, or an amino acid sequence comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;preferably, the B7-H3 antibody comprises a heavy chain variable region and a light chain variable region, wherein the VH and VL respectively comprise the amino acid sequences of SEQ ID NO: 3 and SEQ ID NO: 4, or amino acid sequences having at least 90%, 95%, or 99% identity thereto, or amino acid sequences comprising one or more (preferably 1-10, more preferably 1-5) amino acid additions, deletions, and / or substitutions relative thereto;most preferably, the B7-H3 antibody comprises a heavy chain variable region having the amino acid sequence as shown in SEQ ID NO: 3 and a light chain variable region having the amino acid sequence as shown in SEQ ID NO: 4.

12. A polynucleotide encoding an antibody according to any one of claims 1-11.

13. A vector, preferably an expression vector, comprising a polynucleotide according to claim 12.

14. A host cell comprising a polynucleotide according to claim 12 or a vector according to claim 13,optionally wherein the host cell is a mammalian cell.

15. A method for producing an antibody according to any one of claims 1-11, the method comprising: culturing a host cell comprising a polynucleotide encoding the polypeptide chains of the antibody under conditions suitable for expressing the polypeptide chains; and assembling the polypeptide chains to produce the antibody under conditions suitable for the assembly.

16. An immunoconjugate or immunofusion comprising an antibody or antigen-binding fragment thereof according to any one of claims 1-11.

17. An antibody-drug conjugate (ADC) comprising the structure shown in formula (I):Ab-(L-D)n           (I)or a pharmaceutically acceptable salt or solvate thereof,wherein:Ab is an antibody according to any one of claims 1-11;L is a linker;D is a drug, preferably an anti-tumor compound; andn is an integer selected from 1 to 16, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, or a range defined by any two integers from 1 to 10.

18. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to claim 17, wherein the anti-tumor compound is a cytotoxic agent, such as a camptothecin compound, preferably Exatecan, Dxd, or a derivative thereof.

19. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-18, wherein D is a camptothecin compound comprising the structure shown in formula (D-1):wherein:Ra1 is selected from hydrogen atom, tritium atom, and C1-C6 alkyl;Ra2 is selected from a bond, -C(=O)-CR1R2-(CR3R4)m-O-*, -C(=O)-CR1R2-(CR3R4)m-NH-*, -C(=O)-O-CR1R2-(CR3R4)m-O-*, -C(=O)-O-CR1R2-(CR3R4)m-NH-*,wherein R1 and R2 are each independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C3-C8 cycloalkyl, C3-C8 cycloalkyl C1-C6 alkyl, and C6-C10 aryl C1-C6 alkyl; or R1 and R2, together with the carbon atom to which they are attached, form a C3-C8 cycloalkyl group;R3 and R4 are each independently selected from hydrogen and C1-C6 alkyl;m is an integer from 0 to 6;Ra3 is selected from H, halogen, C1-C6 alkyl, C1-C6 haloalkyl, -OR5 and -SR5;Ra4 is selected from H, halogen, CN, C1-C6 alkyl, C1-C6 haloalkyl, and -OR5; andeach R5 is independently selected from H and C1-C4 alkyl,where * indicates the site attached to the linker L unit.

20. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to claim 19, whereinRai is H;Ra2 is -C(=O)-O-CH2-(CH2)m-O-, where m is an integer of 0, 1, 2, 3, 4, 5, or 6, preferably m=3-5; preferably Ra2 is -C(=O)-O-(CH2)4-O-;Ra3 is Ci-C6 alkyl, preferably methyl;Ra4 is halogen, preferably F.2i. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims i7-20, wherein D has a structure as shown in formula (D-ia) or formula (D-ib):(D-ib)wherein Rai, Ra2, Ra3 and Ra4 are as defined in claim i9 or 20.

22. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims i7-2i, wherein D has the structure shown in formula (D-2):preferably, D has a structure shown in formula (D-2a) or formula (D-2b):

23. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims i7-22, wherein D has the structure shown in formula (D-3):preferably, D has a structure shown in formula (D-3a) or formula (D-3b), especially the structure shown in formula (D-3a):

24. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-23, wherein L is a peptide-containing linker and comprises a structure of formula (II):-Z-Y-M-,       (II)whereinZ is a linking group attached to Ab,Y is an amino acid-containing enzyme-cleavable peptide linker,M is absent or is a spacer group for attachment to drug D.

25. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to claim 24, wherein the Y unit comprises a peptide or peptide analog selected from: *-Val-Ala-, *-Val-Cit-, *-Glu-Val-Cit-, *-Glu-Gly-Cit-, *-Gly-Phe-Gly- , *-Gly-Val-Cit- , *-Gly-Val-Ala- , *-Gly-Phe-Gly-, *-Phe-Gly-, *-Gly-Phe-Lys-, *-Phe-Lys- , *-Gln-Val-Ala-, *-Gln-Val-Cit- , *-Asp-Val-Ala- , *-Lys-Gly-Val-Ala- , *-Lys-Gly-Val-Cit- , *-Lys-Gly-Gly-Val-Ala- , *-Lys-Gly-Gly-Val-Cit- , *-Gly-Gly-Phe-Gly- , *-Lys-Gln-Val-Cit-, *-Lys-Gln-Val-Ala-, *-Lys-Glu-Val-Cit-, *-Lys-Glu-Val-Ala-, *-Lys-Asp-Val-Cit- , *-Lys-Asp-Val-Ala- , *-Glu-Val-Ala- , *-Lys-Val-Ala-, *-Lys-Val-Cit-, -Val-Lys-, *-Asp-Val-Cit- , *-Ala-Ala-Ala-, or *-cBu-Cit-, where * indicates the attachment site to Z;preferably, Y is -Val-Cit- or -Val-Ala-, more preferably, Y has the structure:where the asterisk on the left indicates attachment to the Z linking group, and the wavy line on the right indicates attachment to the M (if M is present), or directly to the drug D.

26. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to claim 24 or 25, wherein Z has the following structure in the direction from the Ab unit side to the Y unit side:-Z1-Z2-Z3-Z4-,wherein,Z1 is a 5-10 membered heterocyclyl, preferably containing 1-3 heteroatoms selected from N, S, and O; more preferably, Z1 is selected fromZ2 is selected from a bond, -C(=O)-, *-C1-C10 alkylene-C(=O)-, *- C3-C10 alkynylene-C(=O)-, *- C3-C10 alkenylene-C(=O)-, and *-heteroaryl-C1-C10 alkylene-C(=O)-,Z3 is absent or is *-R6-(CH2-CH2-O-)x-R7-, where x is an integer from 0 to 5, preferably x=1 or 2;Z4 is absent or is *-R8-(CH2-CH2-O-)y-R9-, where y is an integer from 0 to 12, preferably y = 6, 7, 8, 9, or 10;R6 and R8 are each independently selected from a bond, C1-4 alkylene, -NH-, -heteroaryl-, and *-NH-C1-4 alkylene-heteroaryl-, wherein the heteroaryl is a 5- or 6-membered nitrogen-containing heteroaryl, preferably triazolyl; R7and R9 are each independently selected from -C(=O)-, *-C(=O)-NH-, C1-4 alkylene, *-C1-4 alkylene-C(=O)-,  *-C1-4 alkylene-C(=O)-NH-,  *-NH-C(=O)-(CH2OCH2)-C(=O)-, and *-C1-4 alkylene-NH-C(=O)-(CH2OCH2)-C(=O)-,preferably, R6 and R8 are each independently selected from -NH-, and R7 and R9 are each independently selected from -C(=O)-, *- C1-4 alkylene -C(=O)-, *- C1-4 alkylene-NH-C( = O)-(CH2OCH2)-C(=O)-, wherein the heteroaryl is a 5-membered or 6-membered nitrogen-containing heteroaryl, preferably triazolyl,wherein * indicates the attachment site towards the Ab unit side.

27. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to claim 26, wherein -Z1-Z2-Z3- is selected from:where:n1 is an integer from 1 to 8, for example, 1, 2, 3, 4, 5, or 6;n2 is an integer from 0 to 5, for example, 1 or 2;n3 is an integer from 1 to 4, for example, 1 or 2;Z4 is absent or is8, 9, or 10,, where n4 is an integer selected from 0-12, such as 1, 2, 3, 4, 5, 6, 7,wherein * indicates the attachment site towards the Ab unit, and ^ indicates the attachment site towards the Y unit.

28. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 24-27, wherein Z has a structure selected from the following:where n1 is an integer from 1 to 6, n2 is an integer of 1 or 2, and n4 is an integer from 1 to 10, preferably, Z has a structure selected from:orwhere the asterisk on the left indicates the attachment site to the antibody Ab, and the wavy line on the right indicates the attachment site to the unit Y.

29. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 24-28, wherein M is absent, or is amino-C1-C3 alkylene, for example, -NH-CH2-, or amino-phenyl-C1-C3 alkylene-O-C(=O)-,preferably, M is selected from:andwherein R10 is selected from: H and C1-C6 alkyl; n5 is 1, 2, 3 or 4; n6 is 1, 2, 3, 4, 5 or 6,more preferably, M is:Owhere the asterisk on the left indicates the attachment site to the Y unit, and the wavy line on the right indicates the attachment site to the drug D unit.

30. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 24-29, wherein the L linker has the structure:or the L linker has the structure:wherein Y is as defined in claim 25, preferably Y is -Val-Cit- or Val-Ala,wherein n1 is an integer from 1 to 6, n2 is an integer of 1 or 2, and n4 is an integer from 1 to 10, preferably, the L linker has a structure selected from:where the asterisk on the left indicates the attachment site to the antibody (Ab) unit, and the wavy line on the right indicates the attachment site to the drug (D) unit.

31. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-30, wherein the L-D unit of formula I is linked to the antibody by forming a thioether bond with a thiol group of a cysteine on the light chain and / or heavy chain of Ab.

32. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-31, wherein the ADC comprises a structure selected from formula (I-1) and formula (I-2):Aband(I-1)F(I-2),wherein Ab and n are as defined in claim 17,preferably, the Ab comprises a first heavy chain, a first light chain, a second heavy chain, and a second light chain having the amino acid sequences of SEQ ID NOs: 24, 23, 26, and 25, respectively; or comprises a first heavy chain, a first light chain, a second heavy chain, and a second light chain having the amino acid sequences of SEQ ID NOs: 24, 23, 27, and 25, respectively, orthe Ab comprises a first heavy chain, a first light chain, a second heavy chain, and a second light chain having the amino acid sequences of SEQ ID NOs: 54, 23, 55, and 25, respectively; or comprises a first heavy chain, a first light chain, a second heavy chain, and a second light chain having the amino acid sequences of SEQ ID NOs: 54, 23, 56, and 25, respectively.

33. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-32, wherein the ADC has an average DAR of 2-10, 2-6, 4-8, 6-8, or 7-8.

34. The antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-33, wherein the ADC comprises the structure of formula (I-2):(I-2),wherein the Ab comprises or consists of a first heavy chain, a first light chain, a second heavy chain, and a second light chain having the amino acid sequences of SEQ ID NOs: 54, 23, 55, and 25, respectively, andwherein the ADC has an average DAR of about 6-8, preferably about 8.

35. A pharmaceutical composition comprising an antibody according to any one of claims 1-11 or an immunoconjugate or immunofusion according to claim 16 or an antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-34, and a pharmaceutically acceptable carrier.

36. An antibody according to any one of claims 1-11 or an immunoconjugate or immunofusion according to claim 16 or an antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-34, for use as a medicament, or for use in the manufacture of a medicament, preferably wherein the medicament is for treating and / or preventing cancer in an individual.

37. A method of treating or preventing cancer, comprising administering to an individual in need thereof an antibody according to any one of claims 1-11 or an immunoconjugate or immunofusion according to claim 16 or an antibody-drug conjugate or a pharmaceutically acceptable salt or solvate thereof according to any one of claims 17-34.

38. The use according to claim 36 or the method according to claim 37, wherein the cancer is a B7-H3 or EGFR positive solid tumor or hematological tumor, selected from, for example, bladder cancer, breast cancer, cervical cancer, colorectal cancer, esophageal cancer, glioma, kidney cancer, liver cancer, lung cancer, ovarian cancer, pancreatic cancer, prostate cancer, gastrointestinal cancer, skin cancer, squamous cell carcinoma and adenocarcinoma,optionally, the cancer is skin cancer (such as cutaneous squamous cell carcinoma), head and neck cancer, throat cancer (such as pharyngeal squamous cell carcinoma), esophageal cancer (such as esophageal squamous cell carcinoma), intestinal cancer (such as colon cancer, rectal cancer, colorectal cancer), or lung cancer (such as non-small cell lung cancer, lung squamous cell carcinoma, lung adenocarcinoma).

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