TW202415406A - Methods of treating cancer and the pharmaceutical compositions thereof - Google Patents

Abstract

A method for treating cancer in a subject comprising, administering to the subject a bispecific antibody having a binding specificity to EGFR and HER3 and a therapeutic agent, wherein the therapeutic agent comprises a tyrosine kinase inhibitor (TKI), an alkylating agent, an anti- metabolite, an anti-microtubule agent, a cytotoxic antibiotic, a topoisomerase inhibitor, a chemoprotectant, or a combination thereof.

Description

Method for treating cancer and pharmaceutical composition thereof

This application claims the benefit of the filing date of U.S. provisional application serial number 63/251,664, filed on October 3, 2021, under patent law, the entire contents of which are incorporated herein by reference.

This application relates to a combination therapy that can be used to treat cancer. Specifically, this application relates to a combination therapy comprising a bispecific antibody that specifically binds to human EGFR and HER3 and a chemotherapeutic agent that includes a tyrosine kinase inhibitor.

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and no admission is made that this section includes prior art.

The human epidermal growth factor receptor family contains four receptor tyrosine kinases (EGFR/HER1, HER2, HER3, and HER4). The role of EGFR in gene expression, cell proliferation, adhesion, angiogenesis, apoptosis, and tumor metastasis has been extensively studied. EGFR is overexpressed in more than 90% of head and neck squamous cell carcinomas (HNSCC). High levels of EGFR mutations are found in non-small cell lung cancer (NSCLC). Although EGFR and HER3 are frequently upregulated and/or mutated in a variety of tumors, HER3 is a catalytically impaired member of the EGFR family, allowing the kinase domains of EGFR, HER3, and HER2 to form a heterodimeric complex. Cancer-associated HER3 mutations enhance the allosteric activator function of HER3 by reusing local interactions at the dimerization interface.

In the case of HNSCC patients, standard care such as postoperative radiation therapy and concurrent cisplatin-based chemotherapy has improved tumor control rates and disease-free survival rates. However, the overall survival rate remains at approximately 50%.

Several tyrosine kinase inhibitors (TKIs) have been developed as targeted chemotherapy to inhibit receptor tyrosine kinase activity in human cancer cells. TKIs can be used as monotherapy targeting the intracellular kinase domain of EGFR signaling. For example, gefitinib (IRESSA ^® , AstraZeneca) is approved for the treatment of NSCLC with EGFR exon 19 deletion (exon19del) or exon 21 (L858R) substitution mutations. The clinical benefit of TKI treatment as a single agent or in combination with radiation therapy appears to be limited to 10-15% of HNSCC patients. Combinations of EGFR-TKI targeted chemotherapy and standard chemotherapy are being studied in HNSCC patients (Rebuzzi et al., 2019). These approaches may have their own limitations. For example, the doses of therapeutic agents in a chemotherapeutic combination may have significant toxicity due to their non-specific mechanisms of action, which may become a limiting factor in the efficacy of the treatment regimen.

Single-agent targeted chemotherapy (such as TKI) or targeted immunotherapy that show initial efficacy cannot produce durable cancer control (Wu et al., 2020). In the case of targeted immunotherapy, Cetuximab (ERBITUX ^® ), a monoclonal antibody (mAb) targeting the extracellular domain of EGFR, has been approved as a monotherapy for HNSCC clinical indications (i.e., recurrent or metastatic HNSCC that has progressed after platinum-based therapy), in combination with radiation therapy for locally/regionally advanced HNSCC, in combination with chemotherapy for advanced HNSCC, and in combination with platinum-based therapy with fluorouracil for recurrent locoregional disease or metastatic HNSCC. However, the response rate of cetuximab is limited to approximately 20% in HNSCC patients with high EGFR amplification and independent of human papillomavirus (HPV) status. Adding cetuximab to platinum-based chemoradiation (CRT) does not result in improved outcomes. Furthermore, adding cetuximab to carboplatin/paclitaxel chemotherapy or high-dose radiation therapy provides no survival benefit for unresectable stage III non-small cell lung cancer (NSCLC), another cancer subtype that displays high EGFR expression and mutation rates.

EGFR-targeted monotherapy using mAbs or TKIs results in relatively low response rates and patients often acquire resistance (Chong et al., 2013; Lim et al., 2018). Less than 5% of HNSCCs carry EGFR mutations, which may explain the limited efficacy. In addition, multiple extracellular receptors and downstream signaling pathways serve as alternatives, and persistently activated oncogenic signaling allows cancers to develop resistance to monotherapy with EGFR inhibitors.

The following invention is only illustrative and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, other aspects, embodiments and features will become clear by reference to the drawings and the following embodiments.

In one aspect, the present application provides a method for treating cancer in an individual. The method may be a combination therapy comprising at least one antibody. In one embodiment, the method comprises the step of administering an antibody and a therapeutic agent to the individual.

The antibody may be a bispecific antibody. In one embodiment, the antibody has binding specificity to EGFR and HER3. In one embodiment, the antibody comprises 3 complementary determining regions (CDRs) of SEQ ID NO: 1, 3 CDRs of SEQ ID NO: 2, or 3 CDRs of SEQ ID NO: 4.

In one embodiment, the antibody comprises a heavy chain variable region (VH) having at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% sequence identity to SEQ ID NO: 1. In one embodiment, the antibody comprises a heavy chain scFv domain having an amino acid sequence having at least 98% sequence identity to SEQ ID NO: 2. In one embodiment, the antibody comprises a light chain variable region (VL) having at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% sequence identity to SEQ ID NO: 4.

In one embodiment, the antibody has a heavy chain and a light chain. In one embodiment, the heavy chain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% sequence identity with SEQ ID NO: 3. In one embodiment, the light chain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% sequence identity with SEQ ID NO: 5.

The therapeutic agent can be any cancer therapeutic agent or a combination of such agents. In one embodiment, the therapeutic agent can be a tyrosine kinase inhibitor (TKI), an alkylating agent, an anti-metabolite, an anti-microtubule agent, a cytotoxic antibiotic, a topoisomerase inhibitor, a chemoprotectant, or a combination thereof. In one embodiment, the therapeutic agent can be osimertinib, paclitaxel, docetaxel, irinotecan, carboplatin, pemetrexed, cisplatin, or a combination thereof.

In one embodiment, the tyrosine kinase inhibitor (TKI) comprises erlotinib, gefitinib, icotinib, AZD3759, sapatinib, afatinib, dacomitinib, deratinib, poziotinib, tarlox-TKI, osimertinib, nazartinib, olmutinib, rociletinib, naquotinib, lazertinib, EAI045, CLN081, AZ5104, mobocertinib, a derivative thereof, or a combination thereof.

In one embodiment, the method of treating cancer uses a combination therapy comprising a bispecific antibody and osimertinib. In one embodiment, the antibody can be administered by intravenous infusion at least once a week (QW), once every two weeks or every other week (Q2W), once every three weeks (Q3W), or on the first and eighth days of every three weeks (D1D8Q3W) at a dose of, for example, 6 mg/kg, 9 mg/kg, 12 mg/kg, 14 mg/kg, 16 mg/kg, or 21 mg/kg. In one embodiment, if the infusion reaction is tolerated within 120 min ± 10 min of the first dose after the first intravenous infusion, the subsequent infusion can be completed within 60-120 min. In one embodiment, the antibody and the therapeutic agent can be used on the same day, and the infusion of the therapeutic agent can continue after the antibody infusion is completed. In one embodiment, the amount of osimertinib administered is at least about 40 mg/kg, about 80 mg/kg, about 120 mg/kg, about 160 mg/kg, or about 180 mg/kg.

In one embodiment, the alkylating agent comprises busulfan, cyclophosphamide, temozolomide, carboplatin, cisplatin or a combination thereof.

In one embodiment, the method uses a combination comprising a bispecific antibody and carboplatin. In one embodiment, the carboplatin is administered at a dose of about 100 mg/m2 to about 500 mg/m2. In one embodiment, the carboplatin is administered at a dose of at least about 200 mg/m2, about 250 mg/m2, about 300 mg/m2, about 360 mg/m2, about 400 mg/m2, or about AUC 5 mg/ml/min, about AUC 6 mg/ml/min, about AUC 7 mg/ml/min. In one embodiment, the carboplatin is administered at a dose of about AUC 5 mg/ml/min.

In one embodiment, the method uses a combination comprising a bispecific antibody and cisplatin. In one embodiment, the dose of cisplatin administered is about 10 mg/m2 to about 180 mg/m2. In one embodiment, the dose of cisplatin administered is at least about 15 mg/m2, about 20 mg/m2, about 30 mg/m2, about 50 mg/m2, about 75 mg/m2, about 100 mg/m2, or about 120 mg/m. In one embodiment, the dose of cisplatin administered is 100 mg/m2, Q3W. In one embodiment, the method further comprises a step of determining dose toxicity after the initial infusion or the first course of treatment. If the dose toxicity is too great, the dose can be reduced to 80%.

In one embodiment, the anti-metabolite may include 6-hydroxypurine, fludarabine, 5-fluorouracil, gemcitabine, cytarabine, pemetrexed, methotrexate, derivatives thereof, or combinations thereof.

In one embodiment, the method uses a combination of a bispecific antibody and pemetrexed. In one embodiment, the dose of pemetrexed administered is about 150 mg/m2 to about 800 mg/m2. In one embodiment, the dose of pemetrexed administered is at least about 250 mg/m2, about 500 mg/m2, or about 750 mg/m2. In one embodiment, the dose of pemetrexed administered is about 500 mg/m2. In one embodiment, the method further comprises the step of determining dose toxicity after the initial infusion or the first course of treatment. If the dose toxicity is too great, the dose is reduced to 80%.

In one embodiment, the present application uses a combination therapy comprising a bispecific antibody in combination with pemetrexed and cis-platinum. In one embodiment, the antibody can be administered by intravenous infusion at least once a week (QW). In one embodiment, the administration of pemetrexed and cis-platinum (AP) can follow the drug instructions and standard usage and can be administered immediately after the completion of the antibody.

In one embodiment, the anti-microtubule agent comprises docetaxel, eribulin, ixabepilone, paclitaxel, vinblastine, a derivative thereof, or a combination thereof.

In one embodiment, the method uses a combination therapy comprising a bispecific antibody and paclitaxel. In one embodiment, the antibody can be administered by intravenous infusion once a week (QW). In one embodiment, paclitaxel can be administered in an amount of about 20 mg/m2 to about 200 mg/m2. In one embodiment, paclitaxel is administered in an amount of at least about 40 mg/m2, about 80 mg/m2, about 135 mg/m2, or about 175 mg/m2. In one embodiment, the dose of paclitaxel can be 80 mg/m2 QW.

In one embodiment, the antibody and paclitaxel can be used on the same day. In one embodiment, paclitaxel can be pretreated and injected within 3 hours after the antibody infusion. In one embodiment, the method can further include the step of determining the dose toxicity after the initial infusion. If the dose toxicity is too great, the dose is reduced to 80%.

In one embodiment, the present application provides a method of treating cancer using a combination therapy comprising a bispecific antibody in combination with paclitaxel and cis-platinum. In one embodiment, the antibody can be administered by intravenous infusion at least once a week (QW). In one embodiment, the administration of paclitaxel and cis-platinum (TP) can follow the drug instructions and standard usage and can be administered immediately after the antibody is completed.

In one embodiment, the method may use a combination of a bispecific antibody and docetaxel. In one embodiment, the dose of docetaxel administered is at least about 35 mg/m2 D1D8D215Q3W. In one embodiment, the method further comprises the step of determining dose toxicity after the initial infusion. If the dose toxicity is too great, the dose is reduced to 80%.

In one embodiment, the cytotoxic antibiotic comprises dactinomycin, bleomycin, daunorubicin, doxorubicin, a derivative thereof, or a combination thereof.

In one embodiment, the topoisomerase inhibitor comprises etoposide, irinotecan, topotecan, a derivative thereof, or a combination thereof.

In one embodiment, the method may use a combination of a bispecific antibody and irinotecan. In one embodiment, the antibody is administered by intravenous infusion once every 2 weeks (Q2W). In one embodiment, irinotecan may be administered in an amount of about 50 mg/m2 to about 250 mg/m2. In one embodiment, irinotecan may be administered in an amount of at least about 80 mg/m2, 130 mg/m2, 150 mg/m2, 180 mg/m2, 200 mg/m2, or 220 mg/m2. In one embodiment, the dose of irinotecan may be 180 mg/m2 Q2W, and the method may follow the drug instructions. In one embodiment, the antibody and irinotecan may be administered on the same day, and irinotecan may be injected after the antibody infusion.

In one embodiment, the chemical protective agent comprises methyltetrahydrofolate or a derivative thereof.

In one embodiment, the antibody can be combined with one or more therapeutic agents for the treatment of cancer. In one embodiment, the antibody can be combined with standard chemotherapy. In one embodiment, the therapeutic agent or combination of therapeutic agents is administered according to the dose, regimen or method of established cancer therapy.

The antibody and therapeutic agent may be administered simultaneously or sequentially as a single treatment session.

In one embodiment, the antibody and the therapeutic agent are administered separately to the individual in alternating treatment sessions. In one embodiment, the antibody and the therapeutic agent are administered simultaneously and sequentially. In one embodiment, the antibody is administered at a time separate from the therapeutic agent.

In one embodiment, the antibody may be administered in a first treatment session and the therapeutic agent is administered in a second treatment session. In one embodiment, the duration of the first treatment session may be about 7 days to about 728 days. In one embodiment, the duration of the second treatment session is about 1 day to about 728 days. In one embodiment, the interval between the first treatment session and the second treatment session is about 7 to about 21 days.

In one embodiment, the antibody may be administered once a week (Q1W), once every two weeks (Q2W), once every three weeks (Q3W), or on day 1 and day 8 every three weeks (D1D8Q3W).

The antibody can be administered in a fixed dose, in a dose calculated in mg/kg, or in a dose calculated in mg/m2. In one embodiment, the antibody is administered in an amount of about 0.1 mg/kg to about 50 mg/kg. In one embodiment, the antibody is administered in an amount of at least about 0.3 mg/kg, about 1.2 mg/kg, about 3.0 mg/kg, about 6.0 mg/kg, about 9.0 mg/kg, about 12.0 mg/kg, about 16.0 mg/kg, about 21.0 mg/kg, or about 28.0 mg/kg.

The therapeutic agent can be administered according to the drug instructions and standard usage or dosage regimen. In one embodiment, the therapeutic agent can be administered at a dosage of about 6.0 mg/Kg to about 28.0 mg/Kg.

In one aspect, the present application provides a therapeutic composition for treating an individual suffering from cancer. The therapeutic composition may include a combination of an antibody as disclosed herein and a therapeutic agent.

The antibody may be a bispecific antibody having binding specificity to bispecific EGFR and HER3. In one embodiment, the antibody comprises 3 complementary determining regions (CDRs) of SEQ ID NO: 1, 3 CDRs of SEQ ID NO: 2, or 3 CDRs of SEQ ID NO: 4.

In one embodiment, the therapeutic agent can be any therapeutic agent or combination disclosed herein, including, for example, osimertinib, carboplatin, cisplatin, pemetrexed, paclitaxel, derivatives thereof, or combinations thereof.

In one embodiment, either or both of the antibody and the therapeutic agent are administered simultaneously, sequentially or concurrently in the form of a pharmaceutical formulation.

In one aspect, the present application further provides a kit comprising a first container, a second container, and a package insert. The first container comprises at least one dose of a first therapeutic composition comprising an antibody, the second container comprises at least one dose of a second therapeutic composition comprising a therapeutic agent, and the package insert comprises instructions for using the first therapeutic composition and the second therapeutic composition to treat cancer in an individual.

In one embodiment, the instructions may state that the first therapeutic agent composition and the second therapeutic agent composition are intended for treating an individual having a cancer that tests positive for EGFR expression.

The cancer may be a solid tumor. In one embodiment, the cancer is lung adenocarcinoma, head/neck squamous cell carcinoma, kidney cancer, colon cancer, squamous cell lung cancer, thyroid cancer, bladder cancer, melanoma, cervical cancer, prostate cancer, breast cancer, uterine/endometrial cancer, pancreatic cancer, ovarian cancer, or papillary renal cancer.

In one embodiment, the cancer comprises a solid tumor that tests positive for EGFR expression and is selected from the group consisting of lung adenocarcinoma, head/neck squamous cell carcinoma, kidney cancer, colon cancer, squamous cell lung cancer, thyroid cancer, bladder cancer, melanoma, cervical cancer, prostate cancer, breast cancer, uterine/endometrial cancer, pancreatic cancer, ovarian cancer, and papillary renal cancer.

In one embodiment, the cancer is an advanced or metastatic solid tumor.

In the following detailed description, reference will be made to the drawings forming a part thereof. In the drawings, similar symbols generally represent similar components unless the context indicates otherwise. The illustrative embodiments described in the embodiments, drawings, and scope of the invention are not intended to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It is readily understood that the aspects of the present disclosure, as generally described herein and as illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a variety of different configurations, all of which are expressly contemplated herein.

The present disclosure generally and particularly relates to methods, compositions and kits for treating cancer using combination therapy including an antibody and an additional therapeutic agent. Anti-EGFR/HER3 Antibody Therapy (SI-B001)

SI-B001 is a bispecific tetravalent anti-EGFR/HER3 monoclonal antibody (also referred to as SI-1X6.4 in U.S. Patent No. 10,919,977B2, which is incorporated herein by reference in its entirety). Upon administration, SI-B001 binds to both EGFR and HER3 on cancer cells simultaneously, thereby preventing receptor phosphorylation and oncogenic signaling. In essence, SI-B001 exhibits binding to both EGFR and HER3 in a single therapeutic antibody.

Antibody-based immunotherapy inhibits cancer cell proliferation by blocking the binding of growth factors to receptors and preventing homodimer and heterodimer signaling states on the cell surface and by promoting internalization and degradation. On the other hand, small molecules such as tyrosine kinase inhibitors (TKIs) inhibit cytoplasmic kinase activity induced by oncogenic signaling from one or more EGFR family members. All solid tumor cells are heterologous in nature, that is, even the EGFR mutation status and abnormal expression in the cancer of the same patient vary over time. Combination therapy combining the antibodies disclosed herein and additional therapeutic agents provides significant technical advantages of increasing the efficacy of treating heterologous tumor cells at different tumor progression stages, reducing the incidence of recurrence, or both. In one embodiment, the combination of SI-B001 and a TKI combines antibody-based inhibition of EGFR family member-mediated signaling with inhibition of cytoplasmic signaling of the EGFR TKI by attacking perpendicular pathways of EGFR oncogenic signaling. SI-B001 Combination Therapy

In some embodiments, the present disclosure provides a method for treating cancer in a patient in need thereof. The cancer may be, but is not limited to, a solid tumor, soft tissue sarcoma, squamous cell carcinoma, head and neck squamous cell carcinoma (HNSCC), non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), or a cancer expressing EGFR. The method may include administering to the patient an effective amount of SI-B001, optionally in combination with one or more standard of care treatments, additional therapeutic agents, or a combination thereof.

Standard of care treatments for cancers such as, but not limited to, HNSCC, NSCLC, and ESCC are well known to those of ordinary skill in the art and include surgery, radiation therapy, chemotherapy, photodynamic therapy, targeted therapy, or a combination thereof. In some embodiments, the standard of care treatment is selected from chemotherapy using carboplatin ( ^PARAPLATIN® , BMS), cisplatin ( ^PLANTINOL® , BMS), docetaxel (TAXOTERE® ^, Sanofi-Aventis), irinotecan ( ^CAMPTOSAR® , Pfizer), pemetrexed disodium ( ^ALIMTA® , Eli Lilly), afatinib maleate, alectinib ( ^ALECENZA® , Genentech), bleomycin, brigantinib, ceritinib ( ^ZYKADIA® , Novartis), crizotinib ( ^XALKORI® , Pfizer), dabrafenib, doxorubicin HCl, etoposide, everolimus, 5-fluorouracil, gemcitabine HCl, hydroxyurea, azathioprine HCl, methotrexate, sunitinib, trametinib, vinorelbine tartrate (NAVELBINE ^® , Pierre Fabre), topotecan HCl, derivatives thereof, or combinations thereof.

In some embodiments, the additional therapeutic agent may be a tyrosine kinase inhibitor used in targeted chemotherapy, including, for example, erlotinib, gefitinib, icotinib, AZD3759, sapatinib, afatinib, dacomitinib, dasatinib, pocitinib, nazartinib, omotinib, rociletinib, nacatetinib, lazetinib, EAI045, CLN081, AZ5104, mobotinib, and derivatives thereof. In some embodiments, the additional therapeutic agent is osimertinib ( ^TAGRISSO® , AstraZeneca), a third-generation irreversible EGFR inhibitor designed to target mutant EGFR and abnormally expressed EGFR without affecting wild-type EGFR. Osimertinib was well tolerated in patients with advanced or metastatic NSCLC.

In some embodiments, the additional therapeutic agent may be a monoclonal antibody used in targeted immunotherapy, including, for example, cetuximab (anti-EGFR antibody, ^ERBITUX® , Lilly), nivolumab (anti-PD1 antibody, ^OPDIVO® , BMS), pembrolizumab (anti-PD1 antibody, ^KEYTRUDA® , Merck), cemiplimab (anti-PD1 antibody, ^LIBTAYO® , Regeneron), atezolizumab (anti-PD-L1 antibody, ^TECENTRIQ® , Roche), durvalumab (anti-PD-L1 antibody, ^IMFINZI® , AstraZeneca), bevacizumab (anti-VEGF antibody, ^AVASTIN® , Roche) or its biosimilars.

In some embodiments, SI-B001 is administered to patients as a first-line monotherapy for HNSCC, NSCLC, and ESCC. In other embodiments, SI-B001 is administered to patients as a first-line treatment in combination with standard of care treatment for HNSCC, NSCLC, and ESCC, including surgery, radiation therapy, chemotherapy, photodynamic therapy, or targeted immunotherapy, or a combination thereof.

In some embodiments, SI-B001 is administered as a first-line treatment in combination with standard-of-care chemotherapy or docetaxel ( ^TAXOTERE® , Sanofi-Aventis) to patients with lung cancer, including NSCLC, but not limited to recurrent and metastatic non-small cell lung cancer. In other embodiments, SI-B001 is administered as a first-line treatment in combination with standard-of-care chemotherapy or paclitaxel ( ^TAXOL® , BMS; ^ABRAXANE® , Abraxis) to patients with head and neck cancer, including HNSCC, but not limited to recurrent and metastatic HNSCC. In other embodiments, SI-B001 is administered as first-line treatment in combination with standard of care chemotherapy or irinotecan ( ^CAMPTOSAR® , Pfizer) to patients with esophageal cancer, including ESCC, but not limited to recurrent and metastatic ESCC.

In some embodiments, when standard of care treatments fail, such as when surgery fails to remove all cancerous tissue or the cancer becomes partially resistant to chemotherapy or immunotherapy, a second-line treatment is used, which may include well-known second-line treatments for HNSCC, NSCLC, and ESCC. Thus, in some embodiments, the present disclosure provides a method of treating HNSCC, NSCLC, and ESCC in a patient, wherein the cancer is resistant to a first-line treatment, the method comprising administering SI-B001 in combination with a second-line treatment, as appropriate.

In some embodiments, the present disclosure provides a method of treating cancer, the method comprising administering SI-B001 as a second-line treatment. In some embodiments, the present disclosure provides a method of treating resistant cancer, the method comprising administering SI-B001 in combination with another second-line treatment or standard of care second-line treatment for HNSCC (ClinicalTrials.gov ID: NCT05054439, S206), NSCLC (ClinicalTrials.gov ID: NCT05020457, S201), and ESCC (ClinicalTrials.gov ID: NCT05022654, S207, which are incorporated herein by reference in their entirety). In some embodiments, the second-line treatment may be chemotherapy. For example, SI-B001 is administered as a second-line treatment in combination with standard-of-care chemotherapy or paclitaxel for the treatment of HNSCC, NSCLC, and ESCC to patients with HNSCC, NSCLC, and ESCC, including but not limited to recurrent, relapsed, and/or metastatic HNSCC, NSCLC, and ESCC. In some embodiments, the second-line treatment may be a targeted therapy. For example, SI-B001 is administered as a second-line treatment in combination with standard-of-care chemotherapy or osimertinib for the treatment of cancers such as HNSCC, NSCLC, and ESCC to patients with HNSCC, NSCLC, and ESCC, including but not limited to recurrent, relapsed, and/or metastatic HNSCC, NSCLC, and ESCC.

In some embodiments, when first-line or second-line standard of care treatment fails, such as when chemotherapy continues to fail and relapse occurs, a third-line treatment is administered to the patient. In some embodiments, the present disclosure provides a method for treating HNSCC (ClinicalTrials.gov ID: NCT05054439, S206), NSCLC (ClinicalTrials.gov ID: NCT05020457, S201) and ESCC (ClinicalTrials.gov ID: NCT05022654, S207) resistant to first-line and second-line treatments, the method comprising administering SI-B001 as a third-line treatment. In some embodiments, the present disclosure provides a method of treating HNSCC, NSCLC, and ESCC that is resistant to first-line and second-line therapies, the method comprising the step of administering SI-B001 in combination with another third-line therapy or standard of care third-line therapy for HNSCC, NSCLC, and ESCC.

In some embodiments, SI-B001 is administered as a sensitizer for treating HNSCC, NSCLC, and ESCC in patients in need thereof. Without being bound by any theory, it is believed that SI-B001 increases the efficacy of standard care treatments, first-line treatments, second-line treatments, or third-line treatments for HNSCC, NSCLC, and ESCC. In some embodiments, the disclosure provides a method for treating HNSCC, NSCLC, and ESCC in patients in need thereof, the method comprising administering SI-B001 to the patient prior to administering one or more of standard care treatments, first-line treatments, second-line treatments, or third-line treatments. In some embodiments, administering SI-B001 results in more effective treatment of HNSCC, NSCLC, and ESCC than treatments in which SI-B001 is not administered. In some embodiments, the present disclosure provides a method of treating HNSCC, NSCLC and ESCC in a patient in need thereof, the method comprising administering SI-B001 to the patient after administration of one or more of standard of care treatment, first-line treatment, second-line treatment or third-line treatment.

One of ordinary skill in the art will understand the amounts and dosing regimens for administering such additional therapeutic agents for the treatment of HNSCC, NSCLC, and ESCC. As an example, administration of exemplary therapeutic agents suitable for the treatment of HNSCC, NSCLC, and ESCC is summarized in Table 1.

The term "pharmaceutical formulation" refers to the process by which different chemical substances, including active pharmaceutical compounds, are combined to produce a final pharmaceutical product in a dosage form that is stable and acceptable to patients. For drugs administered orally, the active pharmaceutical compound is incorporated into a non-toxic carrier, adjuvant or vehicle that does not destroy the pharmacological activity of the compound formulated with it. The formulated pharmaceutical compound is compatible with these other substances in a manner that does not cause damage (whether direct or indirect). Pharmaceutically acceptable carriers, adjuvants and vehicles that can be used in the compositions of the present disclosure include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins (such as human serum albumin), buffer substances (such as phosphates), glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes (such as protamine sulfate). sulfate), disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethyl cellulose, polyacrylates, wax, polyethylene-polypropylene oxide block polymers, polyethylene glycol and lanolin.

The compositions of the present disclosure may be administered orally, parenterally, by inhalation spray, topically (e.g., by powder, ointment, or eye drops), rectally, nasally, intrabuccally, intravaginally, intracisternal, or by implanted storage capsules. The term "parenteral" as used herein includes subcutaneous, intravenous, intramuscular, intraarticular, intrasynovial, intrasternal, intrathecal, intrahepatic, intralesional, and intracranial injection or infusion techniques. Preferably, the compositions are administered orally, intraperitoneally, or intravenously. The sterile injectable form of the compositions of the present disclosure may be an aqueous or oily suspension. Such suspensions may be formulated using suitable dispersants or wetting agents and suspending agents according to techniques known in the art. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example, in the form of a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, non-volatile oils are conventionally used as solvents or suspending media.

It should also be understood that the specific dosage and treatment regimen for any patient will depend on a variety of factors, including the activity of the specific compound used, age, weight, general health, sex, diet, time of administration, rate of excretion, drug combination, and the judgment of the treating physician and the severity of the disease being treated. The amount of the compound of the present disclosure in the composition will also depend on the compound in the composition.

According to the methods of the present disclosure, the compounds and compositions can be administered using any amount and route of administration that is effective for treating cancer, such as those disclosed herein. The exact amount required may vary from subject to subject, depending on the species, age and general condition of the subject; the severity of the cancer; the dosage; its mode of administration and similar factors. The compounds and compositions of the present disclosure are preferably formulated to facilitate uniformity of dosage of physically discrete units of a dose suitable for the patient to be treated. However, it should be understood that the total daily dosage of the compounds and compositions of the present disclosure will be determined by a medical expert within the scope of professional medical judgment. The specific effective dose for any particular patient or organism will depend on a variety of factors, including the cancer being treated and the severity of the cancer; the activity of the specific compound being used; the specific composition being used; the age, weight, general health, sex, and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound being used; the duration of the treatment; drugs used in combination or concomitantly with the specific compound being used; and similar factors well known in the medical art.

Injectable preparations such as sterile injectable aqueous or oily suspensions can be formulated according to known techniques using suitable dispersants or wetting agents and suspending agents. Sterile injectable preparations can also be sterile injectable solutions, suspensions or emulsions in nontoxic parenterally acceptable diluents or solvents, for example, in the form of solutions in 1,3-butanediol. Acceptable vehicles and solvents that can be employed are especially water, Ringer's solution and isotonic sodium chloride solution. Injectable formulations can be sterilized, for example, by filtering through a bacteria-retaining filter or by incorporating a sterilizing agent in the form of a sterile solid composition that can be dissolved or dispersed in sterile water or other sterile injectable medium before use.

The kits disclosed herein are particularly suitable for administration of different dosage forms, such as oral and parenteral, for administration of separate compositions at different dosing intervals, or for titrating separate compositions against each other. To aid compliance, the kits typically include instructions for administration and may be provided with a memory aid.

As used herein, the terms "a," "an," and "the" are defined to mean "one or more" and include the plural unless the context indicates otherwise.

As used herein, the terms "polypeptide," "peptide," and "protein" are interchangeable and are defined to mean a biological molecule composed of amino acids linked by peptide bonds.

The terms "antigen", "antigenic site" and "epitope" refer to an entity or fragment thereof that can induce an immune response in an organism, particularly an animal, more particularly a mammal including humans. The terms include immunogens and regions thereof that are responsible for antigenicity or antigenic determinants.

The term "antibody" is used in the broadest sense and specifically covers single monoclonal antibodies (including agonist and antagonist antibodies), antibody compositions with multiple epitope specificities, and antibody fragments (e.g., Fab, F(ab') ₂ and Fv), as long as they exhibit the desired biological activity. In some embodiments, the antibody may be a monoclonal antibody, a polyclonal antibody, a chimeric antibody, a single chain antibody, a bispecific antibody or a biactive antibody, a human antibody and a humanized antibody, and active fragments thereof. Examples of active fragments of molecules that bind to a known antigen include Fab, F(ab') ₂ , scFv and Fv fragments, including the products of a Fab immunoglobulin expression library and epitope-binding fragments of any of the antibodies and fragments mentioned above. In some embodiments, antibodies may include immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e., molecules that contain a binding site that can bind to an antigen, antigenic site, or epitope. An immunoglobulin may be any type (IgG, IgM, IgD, IgE, IgA, and IgY) or class (IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2) or subclass of an immunoglobulin molecule. In one embodiment, an antibody may be a complete antibody or any antigen-binding fragment derived from a complete antibody.

A typical antibody refers to a heterotetrameric protein that usually comprises two heavy (H) chains and two light (L) chains. Each heavy chain comprises a heavy chain variable domain (abbreviated VH) and a heavy chain constant domain. Each light chain comprises a light chain variable domain (abbreviated VL) and a light chain constant domain. The "light chain" of an antibody (immunoglobulin) from any vertebrate species can be assigned one of two distinct types, called κ (kappa) and λ (lambda), based on the amino acid sequence of its constant domain. The VH and VL regions can be further subdivided into domains called hypervariable complementation determining regions (CDRs) and more conserved regions called framework regions (FRs). Each variable domain (VH or VL) is usually composed of three CDRs and four FRs arranged in the following order: from amino terminus to carboxyl terminus, FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. Within the heavy chain and light chain variable regions there are binding regions that interact with antigens.

As used herein, the term "monoclonal antibody" refers to an antibody obtained from a substantially homogeneous antibody population, i.e., the individual antibodies constituting the population are identical except for possible naturally occurring mutations that may be present in small amounts. Monoclonal antibodies have high specificity, being directed against one antigenic site as a monospecific antibody or against more than one antigenic site as a multispecific antibody. Furthermore, in contrast to conventional (polyclonal) antibody preparations that typically include different antibodies directed against different determinants (antigenic determinants), each monoclonal antibody is directed against a single determinant on the antigen. In contrast to polyclonal antibody preparations that typically include different antibodies directed against different determinants (antigenic determinants), each monoclonal antibody is directed against a single determinant on the antigen. The modifier "monoclonal" indicates that the antibody is obtained from a substantially homogeneous antibody population and should not be construed as requiring the antibody to be produced by any method. For example, monoclonal antibodies to be used according to the present disclosure may be made by the hybridoma method first described by Kohler and Milstein, Nature, 256:495 (1975), or may be made by recombinant DNA methods (see, e.g., U.S. Patent No. 4,816,567).

Monoclonal antibodies may include "chimeric" antibodies (immunoglobulins) in which a portion of the heavy and/or light chains are identical or homologous to corresponding sequences in antibodies derived from a specific species or belonging to a specific antibody class or subclass, while the remaining chains are identical or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, as long as they exhibit the desired biological activity (U.S. Patent No. 4,816,567; and Morrison et al., Proc. Natl. Acad. Sci. USA, 81:6851-6855 [1984]). Monoclonal antibodies can be produced using a variety of methods, including mouse fusion tumors or phage display (for a review, see Siegel. Transfus. Clin. Biol. 9:15-22 (2002)) or molecular selection of antibodies directly from primary B cells (see Tiller. New Biotechnol. 28:453-7 (2011)). In the present disclosure, antibodies are produced by combining methods of immunizing rabbits, mice, or camels with subsequent strategies such as fusion tumors or display. Rabbits are known to produce antibodies with high affinity, diversity, and specificity (Weber et al. Exp. Mol. Med. 49:e305). In addition to immunization of rabbits followed by B cell culture, other common strategies for antibody generation and discovery include immunization of other animals (e.g., mice, camels) followed by fusion tumors and/or display on phage, yeast, or mammalian cells; or display using synthetic variable gene libraries. This general approach to antibody discovery is similar to that described in Seeber et al. PLOS One. 9:e86184 (2014).

The term "antigen-binding or epitope-binding portion or fragment" refers to an antibody fragment that is capable of binding to an antigen. Such fragments may be able to perform the antigen-binding function of the antibody and additional functions. Examples of binding fragments include, but are not limited to, a single-chain Fv fragment (scFv) consisting of a VL domain and a VH domain of a single arm of an antibody connected in a polypeptide single chain by a synthetic linker, or a Fab fragment that is a monovalent fragment consisting of a VL, a constant light chain (CL), a VH, and a constant heavy chain 1 (CH1) domain. Antibody fragments may be even smaller sub-fragments and may consist of a single domain as well as a CDR domain, a CDR3 region from a VL domain and/or a VH domain (see, e.g., Beiboer et al., J. Mol. Biol. 296:833-49 (2000)). Antibody fragments are produced using conventional methods known to those skilled in the art. Antibody fragments can be screened for utility using the same techniques as intact antibodies.

"Antigen or epitope binding fragments" can be derived from the antibodies of the present disclosure by several known techniques. For example, purified monoclonal antibodies can be cleaved using an enzyme such as pepsin and subjected to HPLC gel filtration. The appropriate fractions containing the Fab fragments can then be collected and concentrated by membrane filtration, etc. For a further description of general techniques for isolating active fragments of antibodies, see, e.g., Khaw, B.A. et al. J. Nucl. Med. 23:1011-1019 (1982); Rousseaux et al. Methods Enzymology, 121:663-69, Academic Press, 1986.

Papain digestion of antibodies produces two identical antigen-binding fragments, called "Fab" fragments, each with a single antigen-binding site, and a residual "Fc" fragment, whose name reflects its ability to crystallize readily. Pepsin treatment produces an F(ab') ₂ fragment that has two antigen-binding sites and is still capable of cross-linking antigen. The Fab fragment may contain the homeostatic domain of the light chain and the first homeostatic domain (CH1) of the heavy chain. The Fab' fragment differs from the Fab fragment in that several residues are added at the carboxyl terminus of the heavy chain CH1 domain, including one or more cysteines from the antibody hinge region. Fab'-SH is the name for Fab' in this article in which the cysteine residue of the homeostatic domain has a free thiol group. F(ab') ₂ antibody fragments were originally produced as pairs of Fab' fragments that have a hinge cysteine between them. Other chemical couplings of antibody fragments are also known.

"Fv" is the smallest antibody fragment that contains a complete antigen recognition and binding site. This region consists of a dimer of one heavy chain variable domain and one light chain variable domain in a tight, non-covalent association. In this configuration, the three CDRs of each variable domain interact to define an antigen binding site on the surface of the VH-VL dimer. In total, the six CDRs confer antigen binding specificity to the antibody. However, even if a single variable domain (or half an Fv containing only three antigen-specific CDRs) has the ability to recognize and bind to an antigen, the affinity is lower than that of the entire binding site.

Depending on the amino acid sequence of the constant domains of their heavy chains, immunoglobulins can be assigned to different classes. There are five major antibody classes: IgA, IgD, IgE, IgG, and IgM, and several of these antibodies can be further divided into subclasses (isotypes), e.g., IgG-1, IgG-2, IgG-3, and IgG-4; IgA-1 and IgA-2. The constant domains of the heavy chains corresponding to the different classes of immunoglobulins are called α, γ, ε, γ, and μ, respectively. The subunit structures and three-dimensional configurations of the different classes of immunoglobulins are well known.

"Multivalent" antibodies bind to multiple sites on a target, which, depending on the number of binding sites, can result in higher functional affinity and avidity relative to their monomeric form. All antibodies are multivalent, e.g., IgG is bivalent and IgM is decavalent.

"Homology" between two sequences is determined by sequence identity. If the lengths of the two sequences being compared are different, the sequence identity is preferably the percentage of nucleotide residues in the shorter sequence that are identical to the nucleotide residues in the longer sequence. Sequence identity can be conveniently determined using a computer program. The causes of deviations that occur in a comparison between a given sequence and the above-mentioned sequences of the present disclosure may be, for example, additions, deletions, substitutions, insertions or recombination.

The term "targeted chemotherapy" refers to molecular targeted therapies used to treat cancer, as well as other medical treatments such as drug therapy, hormone therapy, and cytotoxic chemotherapy. The first drug in targeted therapy or targeted chemotherapy is the anticancer tyrosine kinase inhibitor (TKI) imatinib (GLEEVEC ^® , Novartis). This class of TKIs has significantly improved outcomes in chronic myeloid leukemia, Philadelphia chromosome-positive acute lymphoblastic leukemia, certain types of gastrointestinal stromal tumors, hypereosinophilic syndrome, chronic eosinophilic leukemia, systemic obesity, myelodysplastic syndrome, and cutaneous fibrosarcoma. TKIs have also been used to treat other diseases, such as idiopathic pulmonary fibrosis.

The term "EGFR-TKI" refers to TKI drugs that inhibit the tyrosine kinase activity of the EGFR signaling pathway. Tyrosine kinases are enzymes responsible for activating many proteins through signaling mediated by signal transduction cascades such as EGFR family members. TKIs, also known as "tyrosine phosphorylation inhibitors," do not inhibit protein kinases that phosphorylate serine or threonine residues and can distinguish the kinase domain of EGFR from the kinase domain of insulin receptors. Proteins are activated by the addition of phosphate groups to proteins (phosphorylation). Three generations of EGFR-TKIs have been developed as targeted chemotherapy for the treatment of cancers harboring EGFR mutations and are classified based on their mechanism of action and clinical benefit (Sullivan and Planchard, 2017).

The term "Bliss independence score" refers to the widely used Bliss independence model for analyzing drug combination data when screening candidate drug combinations. The method compares the observed combination response ( Y _O ) with the predicted combination response ( Y _P ), which is obtained based on the assumption that there are no effects from drug-drug interactions. Suppose two drugs, A and B, both inhibit tumor growth: drug A inhibits tumor growth by _Y a percent at dose a and drug B inhibits tumor growth by Y _b percent at dose b. If the two drugs act independently, the perfect additivity of probability theory can be used to predict the combined inhibition percentage _Yab,p as follows: _Yab,P = _Ya + _{Yb -Ya} × _YbThe present disclosure can be more easily understood by reference to the following detailed description of specific embodiments and the examples included therein. Although the present disclosure has been described with reference to specific details of certain embodiments thereof, it is expected that such details should not be construed as limitations on the scope of the disclosure. In fact, in addition to the modifications described herein, a person skilled in the art will understand various modifications to the present disclosure based on the foregoing description and the accompanying drawings. Such modifications are intended to be within the scope of the accompanying patent applications. Examples Example 1. Xenograft Model of Human Cancer

Xenografting of human cancer cells into immunocompromised mice is the gold standard model for preclinical tumor research and testing of anticancer therapies. Generally, a human cancer cell line is injected subcutaneously into mice. A drug or drug combination is administered to one or more groups of mice, while a control group receives no drug. The primary outcome parameter is growth inhibition by the drug, which measures tumor size over time, usually measured externally using calipers. After the tumor reaches a certain size, the mouse is euthanized. The effect of the drug on the tumor is further analyzed at the tissue level or at the molecular level (e.g., DNA, protein). The primary outcome parameter for xenograft models used to test drug efficacy is the growth of treated tumors versus controls. Typically, xenograft tumors grow from 100 mm ³ (6 mm diameter) to 1000 mm ³ (12 mm diameter) within a few weeks. The growth rate generally decreases with larger tumor size, in contrast to the exponential growth seen in (2D) in vitro experiments. Tumor growth inhibition varies depending on the drug and the cell line implanted. The effects of therapeutic agents may be direct on tumor cells, indirect via the microenvironment such as inhibition of angiogenesis, or both.

The safety and therapeutic effects of SI-B001 as monotherapy and in combination with standard of care, chemotherapy, and/or TKI-based targeted therapy were evaluated in HNSCC and NSCLC xenograft models. The experimental animals used were female Balb/c-nu mice aged 5-7 weeks and weighing 17-21 g.

To establish a HNSCC xenograft model, head and neck cancer FaDu cells were transplanted into mice to establish a HNSCC xenograft model. FaDu is a cell line isolated from a hypopharyngeal tumor of a squamous cell carcinoma patient and expresses wild-type EGFR (ATCC).

To establish a xenograft model of NSCLC, two lung cancer cell lines were used. The human lung adenocarcinoma cell line HCC827_936 was derived from the HCC827 cell line isolated from patient NSCLC tissue (ATCC). HCC827_936 cells express EGFR mutations of exon19del and exon20ins. The other lung cancer cell line NCI-H1975 cells (ATCC) express EGFR L858R/T790M double mutations.

Each of the three human cancer cell lines was cultured in RPMI1640 medium containing 10% fetal bovine serum, the cells were collected during the exponential growth phase, resuspended in PBS to an appropriate concentration, and used for subcutaneous tumor implantation in mice. Example 2. Combination therapy of SI-B001 and osimertinib in the HCC827 936 model

To evaluate the anti-tumor efficacy and safety of the combination of experimental drug SI-B001 and osimertinib (Osi), 5×10 ⁶ HCC827_936 cells were subcutaneously implanted into 40 female nude mice and resuspended in PBS (0.1 ml/mouse). When the tumor grew to an average volume of approximately 163 mm ³ , the mice were randomly divided into groups according to tumor size and mouse weight to establish the HCC827_936 xenograft model.

Saline and SI-B001 were administered by intravenous infusion once a week. SI-B001 was administered at 3 different dosing regimens, namely 9 mg/kg, 16 mg/kg, and 28 mg/kg. DMSO and osimertinib were administered orally once a week. Osimertinib was administered at a fixed dose regimen of 96 mg/kg (Table 2).

Tumor volume (mm ³ ) V = 1/2×(a×b) ² , where a represents the long diameter and b represents the short diameter. Relative tumor volume (RTV), RTV=Vt/V0, where V0 is the tumor volume at time 0 and Vt is the tumor volume after treatment at time t. T/C value (%) is an indicator of the tumor response to treatment and is the most commonly used assessment indicator. T/C % = _TRTV / C _RTV × 100%, where _TRTV is the mean RTV of the treatment group and C _RTV is the mean RTV of the control group. The T/C value (%) can be calculated as T/C % = _TTW / _CTW × 100%, where _TTW is the average tumor volume at the end of the experiment in the treatment group and _CTW is the average tumor volume at the end of the experiment in the control group. The relative tumor inhibition rate (tumor growth inhibition, TGI) is one of the indicators of the tumor response to treatment, TGI% = 100% - T/C%.

The mean tumor volume of mice in the vehicle control group was 720.68 mm ³ on day 31, and the mean tumor volume of the control osimertinib single-agent group was 344.53 mm ³ on day 31, and the TGI (%) was 54.89% (p=0.262). The mean tumor volume of the SI-B001 single-agent 9/16/28 mg/kg/mouse groups on day 31 was 789.65 mm ³ , 601.42 mm ³ , and 203.92 mm ³ , respectively, and the TGI (%) was -10.71%, 24.64%, and 73.20%, respectively (compared with the vehicle control group, p=0.783, p=0.654, p=0.123). In each dose group (9/16/28+96 mg/kg/mouse), the combination of SI-B001 and osimertinib corresponded to an average tumor volume of 46.79 mm ³ , 7.75 mm ³ , and 0 mm ³ on day 31, and TGI % was 93.74%, 99.07%, and 100.00% (compared with single-dose SI-B001 at the corresponding dose level, p=0.002, p=0.012, and p=0.268; compared with single-dose osimertinib, p=0.007, p=0.036, and p=0.044), and the anti-tumor effect was better than the corresponding single-dose SI-B001 and single-dose osimertinib. In summary, all dose groups of SI-B001 combined with osimertinib had significantly higher anti-tumor effects (Figure 1a, Table 3). The anti-tumor effects were better than the corresponding single-dose SI-B001 and single-dose osimertinib, which showed a significant synergistic anti-tumor effect using combination therapy. And the level of tumor inhibition was positively correlated with the increased dose of SI-B001.

Body weights of mice were measured throughout the experiment (Fig. 1b). In vehicle group #1, 2 mice died before day 31, with a mortality rate of 40%. In SI-B001 single dose low dose group #3, 1 mouse died before day 31, with a mortality rate of 20%. In SI-B001 single dose medium dose group #4, 3 mice died before day 31, with a mortality rate of 60%. In SI-B001 single dose high dose group #5, 3 mice died before day 31, with a mortality rate of 60%. In osimertinib single dose group #2, 3 mice died before day 31, with a mortality rate of 60%. In combination group #6 SI-B001 low dose group, no mice died before day 31. In the other two combination groups #7 and #8, 3 mice died before day 31, with a mortality rate of 60%. There was no obvious trend in the number of deaths in these groups. This did not show obvious toxicity when combining SI-B001 with osimertinib.

To validate the tumor tissue targets in tumor-bearing mice at the end of the experiment, tumor tissues were obtained after euthanasia of mice and characterized for EGFR and HER3 expression using flow cytometry fluorescence sorting (FACS) analysis (Fig. 1c).

In this example, the treatment plan for the treatment of HNSCC showed the effect of the combination of increasing doses of SI-B001 and osimertinib in the HCC827_936-derived xenograft model. The results showed that osimertinib could achieve some level of cancer control, but mice treated with this TKI eventually relapsed. However, when combined with 2 of the 3 subtherapeutic doses of SI-B001 tested, durable control could be achieved. When osimertinib was combined with one dose of SI-B001 that reached a stable dose, durable control could be achieved. At day 31, significant differences (p<0.05) in tumor volume were evident between all three combinations including SI-B001 when combined with the exemplary TKI osimertinib (Table 3).

These results indicate that the combination of SI-B001 can achieve significantly beneficial therapeutic potential when combined with TKI, which provides support for human clinical trials (Table 1). Example 3. Combination therapy of SI-B001 and osimertinib in the NCI-H1975 model

To evaluate the anti-tumor efficacy and safety of the combination of experimental drug SI-B001 and osimertinib, 5×10 ⁶ NCI-H1975 cells were subcutaneously implanted into 80 female nude mice and resuspended in PBS (0.1 ml/mouse). When the tumors grew to an average volume of approximately 170 mm ³ , the mice were randomly divided into groups according to tumor size and mouse weight to establish a human head and neck squamous cell carcinoma cell NCI-H1975 xenograft model.

Saline and SI-B001 were administered by intravenous infusion once a week. SI-B001 was administered at 3 different dosing regimens, namely 9 mg/kg, 16 mg/kg, and 28 mg/kg. DMSO and osimertinib were administered orally once a week. Osimertinib was administered at a fixed dose regimen of 96 mg/kg (Table 4).

Tumor volume (mm ³ ) V = 1/2×(a×b) ² , where a represents the long diameter and b represents the short diameter. Relative tumor volume (RTV), RTV=Vt/V0, where V0 is the tumor volume at time 0 and Vt is the tumor volume after treatment at time t. T/C value (%) is an indicator of the tumor response to treatment and is the most commonly used assessment indicator. T/C % = _TRTV / C _RTV × 100%, where _TRTV is the mean RTV of the treatment group and C _RTV is the mean RTV of the control group. The T/C value (%) can be calculated as T/C % = _TTW / _CTW × 100%, where _TTW is the average tumor volume at the end of the experiment in the treatment group and _CTW is the average tumor volume at the end of the experiment in the control group. The relative tumor inhibition rate (tumor growth inhibition, TGI) is one of the indicators of the tumor response to treatment, TGI% = 100% - T/C%.

The mean tumor volume of mice in the vehicle control group was 2316.19 mm ³ on day 25, and the mean tumor volume of the control osimertinib single-agent group was 75.02 mm ³ on day 25, and the TGI (%) was 95.35% (p=0.030). The mean tumor volume of the SI-B001 single-agent 9/16/28 mg/kg/mouse groups on day 25 was 253.83 mm ³ , 173.94 mm ³ , and 186.08 mm ³ , respectively, and the TGI (%) was 81.79%, 86.85%, and 84.80%, respectively (p=0.027, p=0.021, p=0.021). In each dose group (9/16/28+96 mg/kg/mouse), the combination of SI-B001 and osimertinib corresponded to an average tumor volume of 49.36 mm ³ , 9.75 mm ³ , and 8.68 mm ³ on day 25, and TGI % was 97.77%, 99.41%, and 99.54% (compared with single-dose SI-B001 at the corresponding dose level, p=0.243, p=0.409, and p=0.399; compared with single-dose osimertinib, p=0.633, p=0.096, and p=0.092), and the antitumor effect was better than the corresponding single-dose SI-B001 and single-dose osimertinib (Figure 2a, Table 5). In summary, all dose groups of SI-B001 combined with osimertinib had significantly higher anti-tumor effects. The anti-tumor effects were better than the corresponding single-dose SI-B001 and single-dose osimertinib, which showed a significant synergistic anti-tumor effect. And the tumor inhibition level was positively correlated with the increased dose of SI-B001.

The weight of mice was measured throughout the experiment (Figure 2b). In vehicle group #1, 1 mouse died before day 25, with a mortality rate of 20%. In each of SI-B001 monotherapy groups #3, #4, and #5, 2 mice died before day 25, with a mortality rate of 40%. In osimertinib monotherapy group #2, no mice died before day 25. In combination groups #6, #7, and #9, no mice died, 1 mouse died, and 1 mouse died before day 25. All surviving mice in all groups did not show significant differences in weight loss during the experiment. There was no obvious trend in the number of deaths among the groups. This did not show obvious toxicity when SI-B001 was combined with osimertinib.

To validate the tumor tissue targets in tumor-bearing mice at the end of the experiment, tumor tissues were obtained after euthanasia of mice and FACS analysis was used to characterize the expression of EGFR and HER3 in tumor tissues (Figure 2c).

In this example, the combination of SI-B001 (EGFR-HER3 bispecific antibody) and osimertinib showed increased drug activity when administered in combination for the treatment of lung cancer cell line NCI-H1975 (as tumor xenografts implanted in Balb/c-nu mice). In this model, osimertinib and SI-B001 treatment as single agents maintained relatively stable disease as measured by tumor volume. However, when osimertinib was combined with any of the 3 treatment doses of SI-B001 tested, significantly enhanced tumor control was achieved at the last evaluable time point (p<0.05) (Table 5). This evidence helps support clinical trials that showed that the ability of SI-B001 treatment in patients can be improved when combined with osimertinib (Table 1). Example 4. Combination therapy of SI-B001 and CarboTaxol (paclitaxel and carboplatin) in the Fadu model

To evaluate the anti-tumor efficacy and safety of the combination of experimental drug SI-B001 with paclitaxel and carboplatin, 5×10 ⁶ FaDu cells were subcutaneously implanted into 80 female nude mice and resuspended in PBS (0.1 ml/mouse). When the tumors grew to an average volume of approximately 230 mm3, the mice were randomly divided into groups according to tumor size and mouse weight to establish a human head and neck squamous cell carcinoma cell FaDu xenograft model.

Saline (vehicle control), cetuximab, SI-B001, paclitaxel, and carboplatin were administered by intravenous infusion once a week. SI-B001 was administered at 3 different dosing regimens, namely 6 mg/kg, 9 mg/kg, and 12 mg/kg. Cetuximab was given at 10.5 mg/kg on day 0, followed by 6.5 mg/kg once a week for the next three doses. Paclitaxel and carboplatin were administered at fixed dosing regimens of 20.6 mg/kg and 28 mg/kg, respectively (Fig. 3a, Table 6).

Tumor volume (mm3) V = 1/2×(a×b) ² , where a represents the long diameter and b represents the short diameter. Relative tumor volume (RTV), RTV=Vt/V0, where V0 is the tumor volume at time 0 and Vt is the tumor volume after treatment at time t. T/C value (%) is an indicator of the tumor response to treatment and is the most commonly used assessment indicator. T/C % = _TRTV / C _RTV × 100%, where _TRTV is the mean RTV of the treatment group and C _RTV is the mean RTV of the control group. The T/C value (%) can be calculated as T/C % = _TTW / _CTW × 100%, where _TTW is the average tumor volume at the end of the experiment in the treatment group and _CTW is the average tumor volume at the end of the experiment in the control group. Relative tumor inhibition rate (tumor growth inhibition, TGI) is one of the indicators of tumor response to treatment, TGI% = 100% - T/C%. SI-B001 vs. chemotherapy vs. SI-B001 + chemotherapy

All dose groups of SI-B001 alone (6, 9, 12 mg/kg) had significant antitumor effects, with TGIs of 96.76%, 97.9%, and 98.8%, respectively. Paclitaxel + carboplatin, a control chemotherapy, had a good antitumor effect, with a TGI of 56.16%; all dose groups of SI-B001 + paclitaxel + carboplatin (6, 9, 12 + 20.6 + 28 mg/kg) were significantly more effective than the control chemotherapy group and SI-B001 alone, with TGIs of 99.2%, 99.23%, and 99.38%, respectively. The combination of SI-B001 + paclitaxel + carboplatin has been shown to have a synergistic anti-tumor effect in the human head and neck squamous cell FaDu xenograft model (Figure 4a). SI-B001 + chemotherapy vs. cetuximab + chemotherapy

All dose groups of SI-B001 monotherapy (6, 9, 12 mg/kg) had significant antitumor effects, with TGIs of 96.76%, 97.9%, and 98.8%, respectively. The control cetuximab monotherapy (TGI of 74.27%) was significantly weaker than the SI-B001 monotherapy group. The control combination of cetuximab + paclitaxel + carboplatin had a good antitumor effect, with a TGI of 79.98%, but was significantly weaker than all SI-B001 monotherapy groups (96.76%, 97.9%, and 98.8%) and SI-B001 chemotherapy combination groups (99.2%, 99.23%, and 99.38%) (Figure 4b, Figure 4c).

The weight of mice was measured throughout the experiment. No mice died in all SI-B001 monotherapy groups, and no significant weight loss was found (Figure 3b). SI-B001 monotherapy has been shown to have low toxicity and good safety. Chemotherapy paclitaxel + carboplatin caused the death of 4 mice before the end of the experiment, with a mortality rate of 80%, and 3 of the mice were found to have severe weight loss (≥20%) before death. The weight of mice in the chemotherapy paclitaxel + carboplatin group fluctuated significantly. Chemotherapy paclitaxel + carboplatin has been shown to be more toxic and less safe than SI-B001 monotherapy. No mice died in the combination of SI-B001 and chemotherapy, and the combination of cetuximab and chemotherapy, and no significant weight loss was found. SI-B001 + chemotherapy and cetuximab + chemotherapy were found to be well tolerated with a good safety profile.

To validate the tumor tissue targets of tumor-bearing mice at the end of the experiment, tumor tissues were obtained after euthanasia of mice and FACS analysis was used to characterize the expression of EGFR and HER3 in tumor tissues (Figure 3c).

In summary, the combination of SI-B001 (EGFR-HER3 bispecific antibody) and CarboTaxol (paclitaxel and carboplatin) showed increased drug activity when combined to treat the head and neck squamous FaDu cell line (as a tumor xenograft implanted in Balb/c-nu mice). In this model, CarboTaxol (paclitaxel and carboplatin) can delay the tumor growth rate, but cannot achieve any measure of tumor regression. When combined with any of the 3 treatment doses of SI-B001 tested, it can achieve enhanced control (Figure 3a). On day 17, when tumor volume could be assessed in all animals, significant differences (p<0.05) in tumor volume were evident between CarboTaxol (paclitaxel and carboplatin) and all three combinations of SI-B001 (Table 7). Based on this evidence, combinations of SI-B001 may achieve increased therapeutic potential when combined with chemotherapy combinations. Example 5. SI-B001 and Cis/Pem combination therapy in the HCC827 model

To evaluate the anti-tumor efficacy and safety of the combination of experimental drug SI-B001 and Cis/Pem, 5×10 ⁶ HCC827_936 cells were subcutaneously implanted into 40 female nude mice and resuspended in PBS (0.1 ml/mouse). When the tumor grew to an average volume of approximately 163 mm3, the mice were randomly divided into groups according to tumor size and mouse weight to establish a human head and neck squamous cell carcinoma cell HCC827_936 xenograft model.

Saline (vehicle control), SI-B001, cisplatin, and pemetrexed were administered by intravenous infusion once a week. SI-B001 was administered at 3 different dosing regimens, namely 9 mg/kg, 16 mg/kg, and 28 mg/kg. Cisplatin and pemetrexed were given at 7.72 mg/kg and 51.48 mg/kg, and when combined with cetuximab or SI-B001, at only 3.86 mg/kg and 25.74 mg/kg (Figure 5a; Table 8).

Tumor volume (mm ³ ) V = 1/2×(a×b) ² , where a represents the long diameter and b represents the short diameter. Relative tumor volume (RTV), RTV=Vt/V0, where V0 is the tumor volume at time 0 and Vt is the tumor volume after treatment at time t. T/C value (%) is an indicator of the tumor response to treatment and is the most commonly used assessment indicator. T/C % = _TRTV / _CRTV × 100%, where _TRTV is the mean RTV of the treatment group and CRTV is the mean RTV of the control group. The T/C value (%) can be calculated as T/C % = _TTW / _CTW × 100%, where _TTW is the average tumor volume at the end of the experiment in the treatment group and _CTW is the average tumor volume at the end of the experiment in the control group. The relative tumor inhibition rate (tumor growth inhibition, TGI) is one of the indicators of the tumor response to treatment, TGI% = 100% - T/C%.

The mean tumor volume of mice in the vehicle control group was 765.1 mm ³ on day 24, and the mean tumor volume of the control Cis/Pem group was 603.1 mm ³ on day 24, and the TGI (%) was 21.2% (p=0.473). The mean tumor volume of the SI-B001 single dose groups of 9/16/28 mg/kg/mouse on day 24 was 682. mm ³ , 588.1 mm ³ , and 205.7 mm ³ , respectively, and the TGI (%) was 10.8%, 23.1%, and 73.1%, respectively (compared with the vehicle control group, p=0.562, p=0.198, p=0.007). In each dose group (9/16/28+3.86+25.74 mg/kg/week), the combination of SI-B001 and Cis/Pem corresponded to an average tumor volume of 337.7 mm ³ , 335.6 mm ³ , and 241.8 mm ³ on day 24, and TGI % was 55.9%, 56.1%, and 68.4% (compared with single-dose SI-B001 at the corresponding dose level, p=0.032, p=0.030, p=0.652; compared with Cis/Pem, p=0.297, p=0.321, p=0.222). The antitumor effect was better than that of the corresponding single-dose SI-B001, except for the high-dose SI-B001, and better than that of Cis/Pem alone.

In summary, the combination of SI-B001 and Cis/Pem has an overall higher anti-tumor effect (Figure 5a, Table 9). The anti-tumor effect is better than the corresponding single agent SI-B001 and Cis/Pem alone, which shows a synergistic anti-tumor effect. And the tumor inhibition level is positively correlated with the increase in the dose of SI-B001.

To assess safety, the weight of mice was measured throughout the experiment (Figure 5b). In vehicle group #1, 1 mouse died before day 24, with a mortality rate of 20%. In SI-B001 single dose low dose group #3, 1 mouse died before day 24, with a mortality rate of 20%. In SI-B001 single dose medium dose group #4, 2 mice died before day 24, with a mortality rate of 40%. In SI-B001 single dose high dose group #5, 2 mice died before day 24, with a mortality rate of 40%. In Cis/Pem group #2, 3 mice died before day 24, with a mortality rate of 60%. In combination groups #6 and #8 SI-B001 low and high dose groups, 2 mice died on day 24, with a mortality rate of 40%. In combination group #7, SI-B001 medium dose group, one mouse died before day 24, with a mortality rate of 20%. There was no obvious trend in the number of deaths among these groups. This showed no obvious toxicity when SI-B001 was combined with Cis/Pem.

The combination of SI-B001 and Cis/Pem showed increased drug activity when administered in combination for the treatment of lung cancer-derived HCC827 cell lines (as tumor xenografts implanted in Balb/c-nu mice). In this model, Cis/Pem delayed tumor growth rate at early evaluable time points, but tumor growth was ultimately uncontrolled. As a single agent, SI-B001 showed dose-dependent control of tumor growth. Enhanced control was achieved when Cis/Pem was combined with subtherapeutic doses of SI-B001.

Based on this evidence, the combination of SI-B001 can achieve increased therapeutic power when combined with chemotherapy. Example 6: Synergistic effect of SI-B001 and TKI or chemotherapy in combination therapy

Following the Bliss definition, if the Bliss independence score is greater than zero, the combination therapy is synergistic. The Bliss definition of synergy was applied to tumor volume data measured over 31 days in the HCC827 xenograft Balb/c-nu mouse model. In this model, mice were treated with cetuximab, SI-B001 low dose (9 mg/kg), SI-B001 medium dose (16 mg/kg), SI-B001 high dose (28 mg/kg), platinum-based double chemotherapy (cis-platinum and pemetrexed), third-generation TKI (osimertinib), and their combinations. Cetuximab, chemotherapy, and osimertinib were given at clinically equivalent doses (Table 9).

Tumor growth rates in each treatment group were calculated using a linear mixed model and the same assumptions as specified in Demidenko, 2019. Tumor growth comparisons of the combinations versus the single agents are shown in Figures 6a-6h. When cetuximab and SI-B001 were combined with osimertinib, all showed significant synergy (Table 10). The synergy of SI-B001 with osimertinib increased with increasing doses of SI-B001 and was stronger than the synergy of cetuximab with osimertinib. The combination of high doses of SI-B001 with osimertinib showed the best overall efficacy. When cetuximab and SI-B001 were combined with chemotherapy, all showed significant synergistic effects, except for the high dose of SI-B001 (Table 11). The combination of SI-B001 medium dose and chemotherapy showed the best overall efficacy.

These results suggest that the combination of SI-B001 can achieve increased therapeutic potential when combined with TKI, which provides support for human clinical trials (Table 1). Example 7: Clinical study of the combination of SI-B001 and chemotherapy as a treatment for solid tumors

In clinical studies, SI-B001 was tested in combination with chemotherapy in NSCLC, HNSCC, and ESCC (Table 1, S201, S206, and S207, respectively).

In the S201 study, SI-B001 was combined with AP (Cis/Pem, cisplatin + pemetrexed) or TP (CarboTaxol, carboplatin + paclitaxel) in 2nd-line NSCLC patients who received only anti-PD-1/L1 monotherapy in the first-line treatment, and SI-B001 was combined with docetaxel in 2nd/3rd-line NSCLC patients who were exposed to platinum-based chemotherapy and anti-PD-1/L1 therapy. Preliminary reports revealed that 46 patients have been enrolled, 91% of whom are male, with a median age of 62.5 years (range, 33-76 years). Among the 46 patients, 1 was treated with SI-B001+AP/TP and 45 were treated with SI-B001+docetaxel, with a median number of prior therapies of 2. Of the 46 patients, 27 were eligible for efficacy assessment (with at least 1 post-baseline tumor assessment), of which 14 remain on treatment. The overall response rate (ORR) was 33.3% (95% CI, 16.5 to 54.0) and the disease control rate (DCR) was 81.5% (95% CI, 61.9 to 93.7). Figure 7a shows the tumor responses in a waterfall plot. The efficacy of SI-B001 in combination with chemotherapy compared with chemotherapy alone in this indication (Schuette et al., 2005) indicates a potential benefit in this patient population.

In the S206 study, SI-B001 was combined with paclitaxel in 2nd/3rd-line HNSCC patients resistant to frontline chemotherapy and anti-PD-1/L1 therapy. Preliminary reports revealed that 23 patients have been enrolled, 87% of whom are male, with a median age of 56 years (range, 36-75 years). All patients received one frontline treatment with chemotherapy and immunotherapy. Of the 23 patients, 9 were eligible for efficacy assessment (with at least 1 post-baseline tumor assessment), and 2 of them remain on treatment. The overall response rate (ORR) was 55.6% (95% CI, 21.2 to 86.3) and the disease control rate (DCR) was 88.9% (95% CI, 51.8 to 99.7). Figure 7b shows the tumor responses in a waterfall plot. Compared to historical data from cetuximab plus chemotherapy (Issa et al., 2021), the better response rates obtained with SI-B001 + paclitaxel treatment appear to be trending toward more clinical benefit in this patient population.

In the S207 study, SI-B001 was combined with irinotecan in 2-line ESCC patients resistant to frontline platinum-based chemotherapy and anti-PD-1/L1 therapy. Preliminary reports revealed that 21 patients were enrolled, 90% of whom were male, with a median age of 58 years (range, 48-70 years). Of the 21 patients, 15 were eligible for efficacy assessment (with at least 1 post-baseline tumor assessment), and 6 of them remain on treatment. The overall response rate (ORR) was 33.3% (95% CI, 11.8 to 61.6) and the disease control rate (DCR) was 80.0% (95% CI, 51.9 to 95.7). Tumor responses are shown in the waterfall plot (Figure 7c). Based on preliminary data, SI-B001 plus irinotecan may be more effective than irinotecan alone or in combination with other chemotherapy in pre-treated ESCC patients (Burkart et al., 2007).

Overall, the combination of SI-B001 and chemotherapy was well tolerated in all three studies. No treatment-related deaths were observed. Therefore, the efficacy and safety data support the further development of SI-B001 in these indications. References: Robichaux JP, Le X, Vijayan RSK, et al. Structure-based classification predicts drug response in EGFR-mutant NSCLC. Nature. 2021 Sep;597(7878):732-737. Wu L, Ke L, Zhang Z, Yu J, Meng X. Development of EGFR TKIs and Options to Manage Resistance of Third-Generation EGFR TKI Osimertinib: Conventional Ways and Immune Checkpoint Inhibitors. Front Oncol. 2020 Dec 18;10:602762. Rebuzzi SE, Alfieri R, La Monica S, Minari R, Petronini PG, Tiseo M. Combination of EGFR-TKIs and chemotherapy in advanced EGFR mutated NSCLC: Review of the literature and future perspectives. Crit Rev Oncol Hematol. 2020 Feb;146:102820. Demidenko, E., & Miller, TW (2019). Statistical determination of synergy based on Bliss definition of drugs independence. PLoS One, 14(11), e0224137. Chong CR, Janne PA. The quest to overcome resistance to EGFR-targeted therapies in cancer. Nat Med 2013;19:1389-400. Lim SM, Syn NL, Cho BC, et al. Acquired resistance to EGFR targeted therapy in non-small cell lung cancer: Mechanisms and therapeutic strategies. Cancer Treat Rev 2018;65:1-10. Sullivan, I and Planchard, D. (2017) Next-generation EGFR tyrosine kinase inhibitors for treating EGFR-mutant lung cancer beyond first line. Front. Med. 3:76. Schuette, W., Nagel, S., Blankenburg, T., et al. (2005). Phase III study of second-line chemotherapy for advanced non-small-cell lung cancer with weekly compared with 3-weekly docetaxel. Journal of Clinical Oncology, 23(33), 8389-8395. Issa, M., Klamer, B., Karivedu, V., et al. (2021). Use of cetuximab added to weekly chemotherapy to improve progression-free survival in patients with recurrent metastatic head and neck squamous cell carcinoma after progression on immune checkpoint inhibitors. Journal of Clinical Oncology ＞ List of Issues ＞ Volume 39, Issue 15_suppl. Burkart, C., Bokemeyer, C., Klump, B., et al. (2007). A phase II trial of weekly irinotecan in cisplatin-refractory esophageal cancer. Anticancer research, 27(4C), 2845-2848. Table 1. Exemplary treatment for human cancers, including but not limited to solid tumors, NSCLC, HNSCC and ESCC. cancer Therapeutic agents Dosage plan Solid tumor 1) SI-B001 monotherapy; 2) SI-B001 plus osimertinib SI-B001 is administered by intravenous infusion at a dose of, for example, 6 mg/kg, 9 mg/kg, 12 mg/kg, 14 mg/kg, 16 mg/kg or 21 mg/kg at least once a week (QW), once every two weeks or every other week (Q2W), once every three weeks (Q3W) or on the first and eighth days of every three weeks (D1D8Q3W); 120 min ± 10 min after the first intravenous infusion, if the infusion reaction is tolerated during the first dose, the subsequent infusion can be completed within 60-120 min; and if SI-B001 and chemotherapy/target therapy are used on the same day, the infusion of the drug should be continued after the completion of the SI-B001 infusion. NSCLC ²⁰¹ 1) SI-B001 plus AP (pemetrexed plus cis-platinum) 2) SI-B001 plus TP (paclitaxel plus cis-platinum) 3) SI-B001 plus docetaxel The dose of SI-B001 was administered by intravenous infusion at least once a week (QW); and the administration of AP, TP, or docetaxel should refer to the drug package insert and standard usage and should be administered immediately after completion of SI-B001. HNSCC ²⁰⁶ 1) SI-B001 plus paclitaxel SI-B001 was administered by intravenous infusion once a week (QW); the dose of paclitaxel was 80 mg/m2 QW. SI-B001 and paclitaxel were used on the same day. Paclitaxel was pretreated and infused no less than 3 hours after SI-B001 infusion. ESCC ²⁰⁷ 1) SI-B001 plus irinotecan The dose of SI-B001 was administered by intravenous infusion once every 2 weeks (Q2W); and the dose of irinotecan was 180 mg/m2 Q2W. The infusion method was based on the drug instructions. SI-B001 and irinotecan were used on the same day, and irinotecan was injected after SI-B001 infusion. Exemplary Indications for Human Cancer: ²⁰¹ Patients with locally advanced or metastatic EGFR wild-type ALK wild-type NSCLC with progressive disease or intolerance to a first line of therapy containing anti-PD-1/L1 antibody or subsequent lines of therapy containing anti-PD-1/L1; ²⁰⁶ Patients with relapsed and metastatic HNSCC (non-nasopharyngeal) with progressive disease or intolerance to prior anti-PD-1/L1 monoclonal antibody concomitantly or without concomitant platinum-based chemotherapy (previously received at least 2 lines of systemic therapy); and ²⁰⁷ Patients with relapsed and metastatic ESCC with progressive disease or intolerance to anti-PD-1/L1 monoclonal antibody concomitantly or without concomitant chemotherapy. Table 2. Experimental Design (Example 2) Group Mouse# treatment Dosage (mg/kg/week) Investment Frequency 1 5 Vehicle (saline + DMSO) 0 iv + po QW/QD 2 5 SI-B001 9 iv QW 3 5 SI-B001 16 iv QW 4 5 SI-B001 28 iv QW 5 5 Osimertinib 96 po QD 6 5 SI-B001 + osimertinib 9 + 96 iv + po QW/QD 7 5 SI-B001 + osimertinib 16 + 96 ivc+po QW/QD 8 5 SI-B001 + osimertinib 28 + 96 iv + po QW/QD Note: The administration volume was 10 ml/kg per mouse. Tumor volume was assessed twice a week. Table 3. Experimental results on day 31 (Example 2) Group Tumor volume x±SD (mm ³ ) TGI % T/C% P-value (Day 31) To Group 1 To Group 2 To Group 3 1 720.7±298.7 N/A N/A N/A N/A N/A 2 789.7±140.7 -10.7% 110.7% 0.783 0.009 N/A 3 601.4±112.9 24.6% 75.4% 0.654 0.252 N/A 4 203.9±91.3 73.2% 26.8% 0.123 0.355 N/A 5 344.5±23.6 54.9% 45.1% 0.216 N/A N/A 6 46.8±34.3 93.7% 6.3% 0.085 0.007 0.002 7 7.8±9.0 99.1% 0.9% 0.078 0.007 0.012 8 0.00±0.00 100% 0% 0.076 0.044 0.268 Table 4. Experimental design (Example 3): Group Mouse# treatment Dosage (mg/kg/week + mg/kg/day) Investment Frequency 1 5 Vehicle (saline + DMSO) 0 iv + po QW/QD 2 5 Osimertinib 96 po QD 3 5 SI-B001 9 iv QW 4 5 SI-B001 16 iv QW 5 5 SI-B001 28 iv QW 6 5 SI-B001+osimertinib 9 + 13.71 iv + po QW/QD 7 5 SI-B001+osimertinib 16 + 13.71 iv + po QW/QD 8 5 SI-B001+osimertinib 28 + 13.71 iv + po QW/QD Note: The administration volume was 10 ml/kg per mouse. Tumor volume was assessed twice a week. Table 5. Experimental results on day 25 (Example 3) Group Tumor volume x±SD (mm ³ ) TGI % T/C% P-value (Day 25) To Group 1 To Group 2 To Group 3 1 2316.2±564.8 N/A N/A N/A N/A N/A 2 75.0±60.3 95.4% 4.7% 0.030 N/A N/A 3 253.8±1179.6 81.8% 18.2% 0.027 0.292 N/A 4 173.9±224.3 86.9% 13.2% 0.021 0.599 N/A 5 186.1±236.2 84.8% 15.2% 0.021 0.576 N/A 6 49.4±83.4 97.8% 2.2% 0.029 0.633 0.243 7 9.8±5.6 99.4% 0.6% 0.029 0.096 0.409 8 8.7±7.8 99.5% 0.5% 0.029 0.092 0.399 Table 6. Experimental design (Example 4) Group Mouse# treatment Dosage (mg/kg/week) Investment Frequency 1 5 Medium 0 iv QW 2 5 Cetuximab 10.5-6.5x3 iv QW 3 5 SI-B001 6 iv QW 4 5 SI-B001 9 iv QW 5 5 SI-B001 12 iv QW 6 5 Cetuximab + Pac +Car (10.5-6.5x3) + 20.6+28 iv QW 7 5 Pac +Car 20.6+28 iv QW 8 5 SI-B001 +Pac +Car 6+(20.6+28) iv QW 9 5 SI-B001 +Pac +Car 9+(20.6+28) iv QW 10 5 SI-B001 +Pac +Car 12+(20.6+28) iv QW Note: The administration volume was 10 ml/kg per mouse. Cetuximab dose "10.5-6.5×3" indicates 10.5 mg/kg on day 0, followed by 6.5 mg/kg once a week for three subsequent doses; Pac means paclitaxel; and Car means carboplatin; tumor volume was assessed twice a week. Table 7. Comparison of tumor volume using t-test on day 17 (Example 4) SI-B001 monotherapy vs SI-B001 + Chemo SI-B001 single therapy 6 (mg/kg) SI-B001 single therapy 9 (mg/kg) SI-B001 monotherapy (12 mg/kg) SI-B001 plus paclitaxel + carboplatin (20.6 + 28) (mg/kg) SI-B001 plus paclitaxel + carboplatin (20.6 + 28) (mg/kg) SI-B001 plus paclitaxel + carboplatin (20.6 + 28) (mg/kg) P value (t test, day 17) 0.0324 0.0471 0.013 Table 8. Experimental design (Example 5) Group Mouse# treatment Dosage (mg/kg/week) Investment Frequency 1 5 Medium 0 iv QW 2 5 Cis/Pem 7.72 + 51.48 iv QW 3 5 SI-B001 9 iv QW 4 5 SI-B001 16 iv QW 5 5 SI-B001 28 iv QW 6 5 SI-B001+Cis+Pem 9 + (3.86 + 25.74) iv QW 7 5 SI-B001+Cis+Pem 16 + (3.86 + 25.74) iv QW 8 5 SI-B001+Cis+Pem 28 + (3.86 + 25.74) iv QW Note: The administration volume was 10 ml/kg per mouse. Pem means pemetrexed; Cis means cisplatin; tumor volume was assessed twice a week. Table 9. Experimental results on day 24 (Example 5) Group Tumor volume x±SD (mm ³ ) TGI % T/C% P-value (Day 24) To Group 1 To Group 2 To Group 3 1 765.1±203.5 N/A N/A N/A N/A N/A 2 603.1±216.3 21.2% 78.8% 0.473 N/A N/A 3 682.7±174.7 10.8% 89.2% 0.562 0.702 N/A 4 588.1±101.7 23.1% 76.9% 0.198 0.939 N/A 5 205.7±76.1 73.1% 26.9% 0.007 0.213 N/A 6 337.7±134.0 55.9% 44.1% 0.021 0.297 0.032 7 335.6±62.9 56.1% 43.9% 0.020 0.321 0.030 8 241.8±102.3 68.4% 31.6% 0.008 0.222 0.652 Table 10. Bliss independence scores of the combination of cetuximab, SI-B001 and osimertinib in the HCC827 xenograft mouse model (Example 6) Treatment 1 Treatment 2 Bliss Rating P-value Cetuximab Osimertinib 0.102 <0.001 SI-B001 9mg/kg Osimertinib 0.115 <0.001 SI-B001 16mg/kg Osimertinib 0.173 <0.001 SI-B001 28mg/kg Osimertinib 0.250 <0.001 Table 11. Bliss independence scores of the combination of cetuximab, SI-B001 and chemotherapy in the HCC827 xenograft mouse model (Example 7) Treatment 1 Treatment 2 Bliss Rating P-value Cetuximab Chemotherapy 0.0002 0.053 SI-B001 9mg/kg Chemotherapy 0.026 <0.001 SI-B001 16mg/kg Chemotherapy 0.052 <0.001 SI-B001 28mg/kg Chemotherapy -0.008 NA Sequence Listing > Sequence Listing ID 1: SI-B001, amino acid sequence of SI-1X6.4 bispecific antibody heavy chain VH with CDRs . QVQLKQSGPGLVQPSQSLSITCTVSGFSLT NYGVH WVRQSPGKGLEWLG VIWSGGNTDYNTPFTS RLSINKDNSKSQVFFKMNSLQSNDTAIYYCAR ALTYYDYEFAY WGQGTLVTVSS > Sequence Listing ID 2: SI-B001, amino acid sequence of SI-1x6.4 bispecific heavy chain scFv domain with CDRs . QVQLQESGGGLVKPGGSLRLSCAASGFTFS SYWMS WVRQAPGKGLEWVA NINRDGSASYYVDSVKG RFTISRDDAKNSLYLQMNSLRAEDTAVYYCAR DRGVGYFDL WGRGTLVTVSSGGGGSGGGGSGGGGSQSALTQPASVSGSPGQSITISC TGTSSDVGGYNFVS WYQQHPGKAPKLMIY DVSDRPS GVSDRFSGSKSGNTASLIISGLQADDEADYYC SSYGSSSTHVI FGGGTKVTVL > Sequence Listing ID 3: SI-B001, SI-1X6.4 bispecific antibody heavy chain full length amino acid sequence. QVQLKQSGPGLVQPSQSLSITCTVSGFSLTNYGVHWVRQSPGKGLEWLGVIWSGGNTDYNTPFTSRLSINKDNSKSQVFFKMNSLQSNDTAIYYCARALTYYDYEFAYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVY TLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGGGGGSGGGGSQVQLQESGGGLVKPGGSLRLSCAASGFTFSSYWMSWVRQAPGKGLEWVANINRDGSASYYVDSVKGRFTISRDDAKNSLYLQMNSLRAEDTAVYYCARDRGVGYFDLWGRGTLVTVSSGGGGSGGGGSGGGGSQSALTQPASVSGSPGQSITISCTGTSSDVGGYNFVSWYQQHPGKAPKLMIYDVSDRPSGVSDRFSGSKSGNTASLIISGLQADDEADYYCSSYGSSSTHVIFGGGTKVTVL ＞Sequence Listing ID 4: SI-B001, SI-1x6.4 bispecific antibody light chain VL amino acid sequence with CDR . DILLTQSPVILSVSPGERVSFSC RASQSIGTNIH WYQQRTNGSPRLLIK YASESIS GIPSRFSG SGSGTDFTLSINSVESEDIADYYC QQNNNWPTT FGAGTKLELK ＞Sequence Listing ID 5: SI-B001, SI-1x6.4 bispecific antibody light chain full length amino acid sequence. DILLTQSPVILSVSPGERVSFSCRASQSIGTNIHWYQQRTNGSPRLLIKYASESISGIPSRFSGSGSGTDFTLSINSVESEDIADYYCQQNNNWPTTFGAGTKLELKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVY ACEVTHQGLSSPVTKSFNRGEC

without

The aforementioned features and other features of the present disclosure will become more fully apparent from the following description and the attached invention patent scope, combined with the accompanying drawings. It should be understood that these drawings only depict several embodiments arranged according to the present disclosure and therefore, are not considered to limit the scope of the present disclosure. The present disclosure will be described with additional features and details through the use of the accompanying drawings, in which:

Figure 1 shows the effects of representative bispecific antibodies, SI-B001 and osimertinib (Osi)-based combination therapy on HCC827-936 tumor cell xenografts in nude mice, where tumor volume was measured as the mean with standard errors for each treatment group (3 dose regimens) and control group (1a); body weight curves during treatment are shown (1b); and the expression of EGFR and HER3 in HCC827-936 cell-derived tumors was detected by flow cytometry fluorescence sorting (FACS) (1c);

FIG. 2 shows the effect of SI-B001 and osimertinib (Osi)-based combination therapy on the treatment of NCI-H1975 tumor cell xenografts in nude mice, wherein tumor volume was measured as the mean with standard errors shown for each treatment group (3 dose regimens) and control group (2a); the curve of body weight during treatment is shown (2b); and the expression of EGFR and HER3 in NCI-H1975 cell-derived tumors was detected by FACS (2c);

FIG. 3 shows the effect of SI-B001 and CarboTaxol (paclitaxel and carboplatin) based combination therapy on Fadu tumor cell xenografts in nude mice, where tumor volume was measured as the mean with standard errors shown for each treatment group (3 dose regimens) and control group (3a); body weight curves during treatment are shown (3b); and the expression of EGFR and HER3 in Fadu cell derived tumors was measured by FACS (3c);

FIG. 4 shows measurements of tumor volume and percent inhibition of tumor growth for SI-B001 + chemotherapy when compared to (4a) SI-B001 or chemotherapy alone, (4b) cetuximab + chemotherapy, and (4c) SI-B001 alone, cetuximab alone, or cetuximab + chemotherapy;

FIG. 5 shows the effect of SI-B001 and cisplatin/pemetrexed based combination therapy on HCC827 tumor cell xenografts in nude mice, where tumor volume was measured as the mean with standard errors shown for each treatment group (3 dose regimens) and control group (5a); body weight curves during treatment are shown (5b);

FIG6 shows the comparative superiority of SI-B100, TKIs, and chemotherapeutics in combination therapy for the treatment of a mouse xenograft model of human tumors as measured by tumor growth rate achieved by: (6a) cetuximab and osimertinib alone or in combination; (6b) SI-B001 and osimertinib alone or in combination; (6c) SI-B00 1-moderate and osimertinib; (6d) SI-B001-high and osimertinib, alone or in combination; (6e) cetuximab and chemotherapy, alone or in combination; (6f) SI-B001-low and chemotherapy, alone or in combination; (6g) SI-B001-moderate and chemotherapy, alone or in combination; and (6h) SI-B001-high and chemotherapy, alone or in combination; and

Figure 7 shows waterfall plots of tumor responses in patients receiving: (7a) SI-B001 plus AP/TP or docetaxel; (7b) SI-B001 plus paclitaxel; and (7c) SI-B001 plus irinotecan.

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TW202415406A_111137481_SEQL.xml

Claims (34)

A method for treating cancer in an individual comprises the step of administering to the individual a bispecific antibody having binding specificity to EGFR and HER3 and a therapeutic agent, wherein the therapeutic agent comprises a tyrosine kinase inhibitor (TKI), an alkylating agent, an anti-metabolite, an anti-microtubule agent, a cytotoxic antibiotic, a topoisomerase inhibitor, a chemoprotectant, or a combination thereof. The method of claim 1, wherein the bispecific antibody comprises 3 complementary determining regions (CDRs) of SEQ ID NO: 1, 3 CDRs of SEQ ID NO: 2, or 3 CDRs of SEQ ID NO: 4. The method of claim 1, wherein the bispecific antibody comprises a heavy chain variable region (VH) having an amino acid sequence having at least 98% sequence identity with SEQ ID NO: 1, a heavy chain scFv domain having an amino acid sequence having at least 98% sequence identity with SEQ ID NO: 2, and a light chain variable region (VL) having an amino acid sequence having at least 98% sequence identity with SEQ ID NO: 4. The method of claim 1, wherein the bispecific antibody comprises a heavy chain and a light chain, wherein the heavy chain comprises an amino acid sequence having at least 98% sequence identity with SEQ ID NO: 3 and the light chain comprises an amino acid sequence having at least 98% sequence identity with SEQ ID NO: 5. The method of claim 1, wherein the therapeutic agent comprises osimertinib, paclitaxel, docetaxel, irinotecan, carboplatin, pemetrexed, cisplatin, or a combination thereof. The method of claim 1, wherein the bispecific antibody and the therapeutic agent are administered simultaneously or sequentially as a treatment session. The method of claim 1, wherein the bispecific antibody and the therapeutic agent are administered separately to the individual in alternating treatment sessions. The method of claim 1, wherein the bispecific antibody is administered in a first treatment session and the therapeutic agent is administered in a second treatment session, wherein the antibody is administered once a week (Q1W), once every two weeks (Q2W), once every three weeks (Q3W), or once a week for two consecutive weeks every three weeks (D1D8, Q3W), and wherein the antibody is administered in a fixed dose, a dose in mg/kg, or a dose in mg/m2. The method of claim 8, wherein the first treatment session lasts from about 7 days to about 728 days. The method of claim 8, wherein the second treatment session lasts from about 1 day to about 728 days. The method of claim 8, wherein the interval between the first treatment session and the second treatment session is about 7 to about 21 days. The method of claim 1, wherein the bispecific antibody is administered at a dose of at least about 0.3 mg/kg, about 1.2 mg/kg, about 3.0 mg/kg, about 6.0 mg/kg, about 9.0 mg/kg, about 12.0 mg/kg, about 14.0 mg/kg, about 16.0 mg/kg, about 21.0 mg/kg, or about 28.0 mg/kg. The method of claim 1, wherein the therapeutic agent is administered in an amount of about 6.0 mg/Kg to about 28.0 mg/Kg. The method of claim 1, wherein the tyrosine kinase inhibitor (TKI) comprises erlotinib, gefitinib, icotinib, AZD3759, sapatinib, afatinib, dacomitinib, dasatinib, pocitrotinib, Tarlox-TKI, osimertinib, nazartinib, omotinib, rociletinib, nacatetinib, lazetinib, EAI045, CLN081, AZ5104, mobotinib, a derivative thereof, or a combination thereof. The method of claim 1, wherein the alkylating agent comprises busulfan, cyclophosphamide, temozolomide, carboplatin, cisplatin or a combination thereof. The method of claim 1, wherein the anti-metabolite comprises 6-hydroxypurine, fludarabine, 5-fluorouracil, gemcitabine, cytarabine, pemetrexed, methotrexate, derivatives thereof, or a combination thereof. The method of claim 1, wherein the anti-microtubule agent comprises docetaxel, eribulin, ixabepilone, paclitaxel, vinblastine, a derivative thereof, or a combination thereof. The method of claim 1, wherein the cytotoxic antibiotic comprises actinomycin, bleomycin, idiomycin, doxorubicin, a derivative thereof, or a combination thereof. The method of claim 1, wherein the topoisomerase inhibitor comprises etoposide, irinotecan, topotecan, a derivative thereof or a combination thereof. The method of claim 1, wherein the chemical protective agent comprises methyltetrahydrofolate or a derivative thereof. The method of claim 1, wherein the therapeutic agent comprises osimertinib, and wherein the amount of osimertinib administered is at least about 40 mg/kg, about 80 mg/kg, about 120 mg/kg, or about 160 mg/kg. The method of claim 1, wherein the therapeutic agent comprises carboplatin, and wherein the amount of carboplatin administered is at least about 200 mg/m2, about 250 mg/m2, about 300 mg/m2, about 360 mg/m2, about 400 mg/m2, about AUC 5 mg/ml/min, about AUC 6 mg/ml/min, or about 7 mg/ml/min. The method of claim 1, wherein the therapeutic agent comprises cis-platinum, and wherein the amount of cis-platinum administered is at least about 15 mg/m2, about 20 mg/m2, about 30 mg/m2, about 50 mg/m2, about 75 mg/m2, about 100 mg/m2, or about 120 mg/m2. The method of claim 1, wherein the therapeutic agent comprises pemetrexed, and wherein the amount of pemetrexed administered is at least about 250 mg/m2, about 500 mg/m2, or about 750 mg/m2. The method of claim 1, wherein the therapeutic agent comprises paclitaxel, and wherein the amount of paclitaxel administered is at least about 40 mg/m2, about 80 mg/m2, about 135 mg/m2, or about 175 mg/m2. The method of claim 1, wherein the therapeutic agent comprises docetaxel, and wherein the dose of docetaxel administered is at least about 35 mg/m2 D1D8Q3W. The method of claim 1, wherein the bispecific antibody and the therapeutic agent are administered simultaneously and sequentially. The method of claim 1, wherein the bispecific antibody is administered at a time separate from the therapeutic agent. The method of claim 1, wherein the cancer comprises a solid tumor that tests positive for EGFR expression and is selected from the group consisting of lung adenocarcinoma, head/neck squamous cell carcinoma, kidney cancer, colon cancer, squamous cell lung cancer, thyroid cancer, bladder cancer, melanoma, cervical cancer, prostate cancer, breast cancer, uterine/endometrial cancer, pancreatic cancer, ovarian cancer, and papillary renal cancer. A therapeutic composition comprises a combination of a bispecific antibody having binding specificity to EGFR and HER3 and a therapeutic agent, wherein the therapeutic agent comprises a tyrosine kinase inhibitor (TKI), an alkylating agent, an anti-metabolite, an anti-microtubule agent, a cytotoxic antibiotic, a topoisomerase inhibitor, a chemoprotectant, or a combination thereof. The therapeutic composition of claim 30, wherein the bispecific antibody comprises 3 complementary determining regions (CDRs) of SEQ ID NO: 1, 3 CDRs of SEQ ID NO: 2, or 3 CDRs of SEQ ID NO: 4, and wherein the therapeutic agent comprises osimertinib, carboplatin, cisplatin, pemetrexed, paclitaxel, a derivative thereof, or a combination thereof. The therapeutic composition of claim 30, wherein the bispecific antibody and the therapeutic agent are in the form of a pharmaceutical formulation for simultaneous, sequential or concurrent administration. A kit comprising a first container, a second container and a package insert, wherein the first container comprises at least one dose of a first therapeutic composition comprising a bispecific antibody having binding specificity to EGFR and HER3, the second container comprises at least one dose of a second therapeutic composition comprising a therapeutic agent, and the package insert comprises instructions for using the first therapeutic composition and the second therapeutic composition to treat cancer in an individual, and wherein the therapeutic agent comprises a tyrosine kinase inhibitor (TKI), an alkylating agent, an anti-metabolite, an anti-microtubule agent, a cytotoxic antibiotic, a topoisomerase inhibitor, a chemoprotectant or a combination thereof. The kit of claim 33, wherein the instructions state that the first therapeutic agent composition and the second therapeutic agent composition are intended for treating an individual having cancer that is positive for EGFR expression.