Means and methods for treating castration-resistant prostate cancer

Abstract

The present invention relates to the field of therapeutic antibodies for use in the treatment of individuals with castration-resistant prostate cancer. More specifically, the present invention relates to the treatment of castration-resistant prostate cancer using a bispecific antibody comprising an antigen binding site that can bind to an extracellular portion of ERBB2 and an antigen binding site that can bind to an extracellular portion of ERBB3. In addition, the present invention relates to the treatment of castration resistant prostate cancer using an antibody comprising an antigen binding site that can bind to an ERBB3 extracellular portion. The invention also relates to the treatment of castration resistant prostate cancer using a combination of one of the antibodies and an androgen receptor axis-targeting agent.

Description

Technical Field

[0001] The present invention relates to the field of antibodies. In particular, the present invention relates to the field of therapeutic (human) antibodies for the treatment of castration-resistant prostate cancer. More specifically, the present invention relates to antibodies that bind to ERBB3, and antibodies that bind to ERBB2 and ERBB3, and their use in combination therapy or combination therapy with androgen receptor axis-targeting agents for the treatment of cancer. Background Art

[0002] In 2020, prostate cancer was the second most common malignancy among men worldwide and the fifth most common cause of cancer death (Sung et al., "Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries." CA Cancer J Clin 71(3):209-249, 2021). In 2021, the number of advanced prostate cancer cases in the United States is estimated to be approximately 250,000 (Siegel et al., "Cancer Statistics, 2021." CA Cancer J Clin 71(1):7-33, 2021), including a subgroup of 30,000 men with castration-resistant prostate cancer (CRPC) (Scher et al., Prostate Cancer Clinical Trials Working (2016). "Trial Design and Objectives for Castration-Resistant Prostate Cancer: Updated Recommendations From the Prostate Cancer Clinical Trials Working Group 3." J Clin Oncol 34(12):1402-1418, 2015). For patients with locally advanced, recurrent or metastatic tumors, current treatment goals include prolonging survival and progression-free interval while maintaining a good quality of life.

[0003] Since the 1940s, the mainstay of treatment for men with metastatic prostate cancer has been androgen deprivation therapy (ADT) alone, using either surgery or chemical castration to suppress testosterone production. Chemotherapy is usually started only after patients no longer respond to ADT alone, at which point the disease is considered castration-resistant.

[0004] Androgen receptor (AR) is a lineage survival factor for luminal cancer cells in prostate tumors and plays an important role in cancer. ADT is still the main treatment for advanced / metastatic diseases targeting AR signaling. It is currently confirmed that the next generation AR signaling inhibitors used for a treatment include abiraterone and enzalutamide (Swami et al., 2020, "Advanced Prostate Cancer: Treatment Advances and Future Directions." Trends Cancer 6 (8): 702-715). These inhibitors can block the androgen receptor (AR) axis more strongly, extending the survival of men with CRPC. However, the degree of survival improvement is still insufficient, and most patients will eventually develop resistance to these new drugs. The resistance mechanism to the next generation of hormone drugs is complex, which may rely on or be independent of AR signaling, and the AR axis may still be an important driver of advanced / metastatic CRPC after deterioration (Verma et al., 2020, Resistance to second generation antiandrogens in prostate cancer: pathways and mechanisms. "Cancer Drug Resist 3 (4): 742-761).

[0005] Although preclinical studies have shown that the ERBB signaling pathway is associated with the progression of CRPC (Craft et al., 1999. A mechanism for hormone independent prostate cancer through modulation of androgen receptor signaling by the HER-2 / neu tyrosine kinase. Nat Med 5(3):280-285), successful targeting of this pathway has not yet been achieved in the clinical setting, and the antitumor activity of ERBB2-targeted drugs (including trastuzumab and afatinib) has not been demonstrated (Ziada et al., 2004, The use of trastuzumab in the treatment of hormone refractory prostate cancer; phase II trial. Prostate 60(4):332-337. Molife et al., 2014, Randomized Phase II trial of nintedanib, afatinib and sequential combination incastration-resistant prostate cancer. Future Oncol 10(2):219-231.).

[0006] More than 30,000 men with metastatic CRPC (mCRPC) are currently receiving one or two systemic therapies, but their disease invariably progresses, requiring follow-up therapy. Therefore, there is a clear unmet medical need for additional treatment options for men whose disease progresses after AR signaling inhibitor therapy. In addition, an increasing number of men with non-metastatic prostate cancer currently receiving AR signaling inhibitor therapy will progress, thereby increasing the number of men with CRPC after AR signaling inhibitor therapy.

[0007] Therefore, there is a need in the art for therapies for castration-resistant prostate cancer. Summary of the invention

[0008] The present invention provides a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3, for use in a method of treating castration-resistant prostate cancer in an individual. The method comprises administering to the individual an effective amount of a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3. Optionally, the treatment method further comprises the use of an androgen receptor axis-targeting agent.

[0009] The present invention provides a method for treating an individual with castration-resistant prostate cancer, the method comprising administering to the individual a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the method comprises screening an individual with castration-resistant prostate cancer or an individual suspected of having castration-resistant prostate cancer before treating castration-resistant prostate cancer.

[0010] The present invention provides an antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB3, for use in a method of treating castration-resistant prostate cancer in an individual. The method comprises administering to the individual an effective amount of an antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB3. Optionally, the treatment method further comprises using an androgen receptor axis-targeting agent. Optionally, the antibody is a monospecific antibody.

[0011] The present invention provides a method for treating castration-resistant prostate cancer in an individual, the method comprising administering to the individual a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3. Optionally, the method comprises screening an individual with castration-resistant prostate cancer or an individual suspected of having castration-resistant prostate cancer prior to treating castration-resistant prostate cancer. Optionally, the antibody is a monospecific antibody.

[0012] Optionally, the method of treatment further comprises screening patients suspected of having castration-resistant prostate cancer according to certain inclusion and exclusion criteria.

[0013] Optionally, the method of treatment further comprises administering to the individual an androgen receptor axis-targeting agent.

[0014] The present invention provides a use of a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3 for the manufacture of a medicament for treating castration-resistant prostate cancer in an individual. Optionally, the treatment or use further comprises the use of an androgen receptor axis-targeting agent.

[0015] Optionally, the castration-resistant prostate cancer has deteriorated after a previous cancer treatment with an androgen receptor axis-targeting agent. Optionally, the castration-resistant prostate cancer has deteriorated after a previous treatment with an androgen receptor antagonist (such as a second-generation androgen receptor antagonist), or has deteriorated after a previous treatment with an androgen synthesis inhibitor (such as abiraterone acetate). Optionally, the castration-resistant prostate cancer has deteriorated after a previous treatment with enzalutamide.

[0016] Optionally, the method of treatment comprising the use or administration of a bispecific antibody of the present invention further comprises the use or administration of an androgen receptor axis-targeting agent. Optionally, the bispecific antibody and the androgen receptor axis-targeting agent are administered during the same period. The period generally comprises a 28-day cycle, during which the bispecific antibody is administered twice, generally on the 1st and 15th day of the cycle (i.e., Q2W), and the androgen receptor axis-targeting agent is administered on every day of the cycle (i.e., QD). Continue to administer the bispecific antibody and / or the androgen receptor axis-targeting agent until a decision is made to stop treatment, but administration may continue as long as it is considered clinically relevant or as long as a clinically relevant effect is observed.

[0017] Thus, optionally, the cancer has worsened after previous treatment with an androgen receptor axis-targeting agent. Alternatively, if the cancer has worsened after previous treatment with an androgen receptor antagonist, the use of the bispecific antibody in the treatment method of the present invention further comprises the use of an androgen receptor antagonist. Alternatively, if the cancer has worsened after previous treatment with an androgen receptor antagonist, the treatment method using the bispecific antibody according to the present invention further comprises the administration of an androgen receptor antagonist. Thus, a combined use can be foreseen, wherein a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3 is used together with an androgen receptor antagonist during the same treatment period.

[0018] Therefore, the present invention optionally provides a combination therapy comprising a first container containing an antibody as described herein and a second container containing an androgen receptor axis-targeting agent. The two components can be formulated as separate pharmaceutical compositions (e.g., as a multi-component kit) and can be administered simultaneously, separately or in any order. As will be appreciated by those skilled in the art, the two components can be provided at different times during the same treatment cycle. Optionally, a treatment cycle consists of 28 days. Optionally, the bispecific antibody of the present invention is administered twice (e.g., Q2W) during the treatment cycle, and the androgen receptor axis-targeting agent is administered every day during the treatment cycle.

[0019] Optionally, the androgen receptor antagonist used in the previous cancer treatment is the same as the androgen receptor antagonist used in the treatment method combined with the bispecific antibody in the present invention. Optionally, the androgen receptor antagonist used in the previous cancer treatment and used in combination with the bispecific antibody of the present invention is enzalutamide. Therefore, optionally, the present invention provides a combination therapy or combination therapy, wherein the bispecific antibody comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3, such as Zenocutuzumab, used together with an androgen receptor antagonist (such as enzalutamide).

[0020] Optionally, enzalutamide is administered at a daily dose of 160 mg.

[0021] Optionally, the cancer has worsened after previous treatment with an androgen synthesis inhibitor. Optionally, if the cancer has worsened after previous treatment with an androgen synthesis inhibitor, the use of the bispecific antibody in the treatment method of the present invention further comprises the use of an androgen synthesis inhibitor. Optionally, if the cancer has worsened after previous treatment with an androgen synthesis inhibitor, the treatment method of the present invention using a bispecific antibody further comprises administering an androgen synthesis inhibitor. Therefore, a combined use can be foreseen, wherein a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3 is used together with an androgen synthesis inhibitor during the same treatment period.

[0022] Optionally, the androgen synthesis inhibitor used in the previous cancer treatment is the same as the androgen synthesis inhibitor used in the treatment method combined with the bispecific antibody of the present invention. Optionally, the androgen synthesis inhibitor used in the previous cancer treatment and used in combination with the bispecific antibody of the present invention is abiraterone acetate, such as Thus, optionally, the present invention provides a combination therapy or combination treatment, wherein the bispecific antibody comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3, such as Zenocutuzumab, during the same treatment period with an androgen synthesis inhibitor (e.g., abiraterone acetate, such as )

[0023] Alternatively, abiraterone acetate such as It is administered at a daily dose of 1000 mg. Alternatively, abiraterone acetate is used in combination with 5 mg of prednisone administered orally twice daily.

[0024] Optionally, the bispecific antibody of the invention is administered or used in an amount of 750 mg once every two weeks. Optionally, the bispecific antibody is Zenocutuzumab.

[0025] Optionally, the antibody of the present invention comprises an antigen binding site that can bind to the extracellular portion of ERBB3, which blocks ERBB3 and its ligand, heregulin. Optionally, the antibody binds to domain III of ERBB3. Optionally, the antibody also comprises an antigen binding site that can bind to the extracellular portion of ERBB2. Optionally, the antibody comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3. Optionally, the antibody is a bispecific antibody. Optionally, the bispecific antibody of the present invention comprises a first antigen binding site that can bind to the extracellular portion of ERBB2 and a second antigen binding site that can bind to the extracellular portion of ERBB3. Optionally, the bispecific antibody has a first antigen binding site that can bind to domain I of ERBB2 and a second antigen binding site that can bind to domain III of ERBB3. Optionally, the affinity of the first antigen binding site to ERBB2 is lower than the affinity of the second antigen binding site to ERBB3. Optionally, the antibody is or comprises Zenocutuzumab.

[0026] Optionally, the present invention provides a method of treatment as disclosed herein, wherein an antibody comprising an antigen binding site that binds to the extracellular portion of ERBB3 is used. Optionally, the antibody is a monospecific antibody.

[0027] Alternatively, the invention provides a method of treating an individual with castration-resistant prostate cancer, the method comprising administering to the individual an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3. Optionally, the antibody comprises an antigen binding site that binds to domain III of ERBB3.

[0028] Alternatively, the invention provides a use of an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3 in the manufacture of a medicament for treating castration-resistant prostate cancer in an individual. Optionally, the antibody comprises an antigen binding site that binds to domain III of ERBB3.

[0029] Optionally, the antibodies of the present invention, including but not limited to bispecific antibodies, comprise an antigen binding site that binds to the extracellular portion of ERBB3, which blocks ERBB3 and its ligand heregulin. Optionally, the antibody also comprises an antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the antibody comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the antibody is or comprises Zenocutuzumab.

[0030] Also provided is a method for screening an individual having castration-resistant prostate cancer for treatment with a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3 or for treatment with an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3, the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, selecting the individual for said treatment.

[0031] Also provided is a method for establishing whether an individual with castration-resistant prostate cancer is likely to respond to treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) screening out the sample for samples that do not exhibit PTEN loss, thereby establishing that the individual from whom the sample is derived is likely to respond to the treatment.

[0032] Also provided is a method for classifying an individual having castration-resistant prostate cancer based on PTEN status prior to treatment with a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3 or prior to treatment with an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3, the method comprising: a) determining PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, classifying the individual from whom the sample was derived as eligible for said treatment.

[0033] Also provided is a method for screening an individual having castration-resistant prostate cancer for treatment with a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3 or for treatment with an antibody comprising an antigen binding site that binds to the extracellular portion of ERBB3, the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample exhibits PTEN loss, selecting the individual for said treatment.

[0034] Also provided is a method for establishing whether an individual with castration-resistant prostate cancer is likely to respond to treatment with a bispecific antibody (which comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3) or to treatment with an antibody (which comprises an antigen binding site that binds to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) screening the sample for PTEN loss, thereby establishing that the individual from whom the sample was derived is likely to respond to the treatment.

[0035] Also provided is a method for classifying an individual having castration-resistant prostate cancer based on PTEN status prior to treatment with a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3 or treatment with an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3, the method comprising: a) determining PTEN status in a sample obtained from the individual; b) if the sample exhibits PTEN loss, classifying the individual from whom the sample was derived as eligible for said treatment.

[0036] Alternatively, the individual is a human individual. The human individual suffers from castration-resistant prostate cancer, or is at risk of suffering from the disease. Alternatively, the individual suffers from metastatic castration-resistant prostate cancer or is at risk of developing metastatic castration-resistant prostate cancer. Therefore, the individual needs to treat castration-resistant prostate cancer or metastatic castration-resistant prostate cancer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The following amino acid sequences are listed: a) amino acid sequence of the common light chain variable region (VL+CL sequence); b) DNA sequence of the common light chain variable region and its translation (IGKV1-39 / jk1), c) DNA sequence and translation of the common light chain constant region, d) translation of the IGKV1-39 / jk5 common light chain variable region, e) V-region IGKV1-39A; f) common light chain CDR1, CDR2 and CDR3 sequences, all according to IMGT.

[0038] Figure 2 The IgG heavy chain sequences used to generate the bispecific molecules are listed: a) CH1 region, b) hinge region, c) CH2 region, d) CH3 domain containing variants L351K and T366K (KK), e) CH3 domain containing variants L351D and L368E (DE).

[0039] Figure 3The nucleic acid and amino acid sequences of the variable region heavy chains are listed. The CDR1, CDR2 and CDR3 sequences of each heavy chain variable region according to the Kabat numbering system are also provided. DETAILED DESCRIPTION

[0040] A subset of CRPC patients develop primary resistance, and eventually almost all patients develop resistance. The development of CRPC resistance is thought to be a subclonal phenomenon, where a subset of tumor cells remain sensitive to androgen deprivation therapy despite the emergence of resistant clones. Without being bound by theory, the inventors recognize that preventing paracrine activation of NRG1 / ERBB3 signaling to attenuate the driver of anti-androgen resistance in CRPC is an option, which uses an antibody comprising an antigen binding site that can bind to domain III of the extracellular portion of ERBB3 as described herein, or an antibody comprising an antigen binding site that can bind to domain III of the extracellular portion of ERBB3 and an antigen binding site that can bind to domain I of the extracellular portion of ERBB2, in a method for treating castration-resistant prostate cancer in an individual.

[0041] The ERBB family of tyrosine kinase transmembrane receptors is also known as the human epidermal growth factor (EGF) receptor family (HER). The family has four members: ERBB (erythroblastoma)-1, ERBB2, ERBB3 and ERBB4. These receptors (reviewed in Yarden and Pines 2012) are widely expressed in epithelial cells. The upregulation of HER receptors or their ligands, such as neuregulin (NRG) (also known as neutropenia (HRG)) or epidermal growth factor (EGF)) is a common event in human cancer (Wilson, Timothy R et al., Nature, Vol. 487, 7408 (2012): 505-9). Overexpression of ERBB1 and ERBB2 occurs particularly in epithelial tumors and is associated with tumor invasion, metastasis, chemotherapy resistance and poor prognosis (Zhang, Hongtao et al., The Journal of clinical investigation, Vol. 117, 8 (2007): 2051-8). In normal breast, ERBB3 has been shown to be important for the growth and differentiation of luminal epithelium. For example, the absence / inhibition of ERBB3 can lead to selective expansion of basal cells on luminal epithelial cells (Balko, Justin M et al., Proceedings of the National Academy of Sciences, Vol. 109, 1 (2012): 221-6). The binding of ligands to the extracellular domain of RTK induces receptor dimerization, which occurs between the same (homodimerization) and different (heterodimerization) receptor subtypes. Dimerization can activate the intracellular tyrosine kinase domain, which can be autophosphorylated, and then many downstream pro-proliferation signal transduction pathways can be activated, including signal transduction pathways mediated by mitogen-activated protein kinase (MAPK) and pro-survival pathway Akt (reviewed in Yarden, Yosef, and Gur Pines. Nature reviews. Cancer, Vol. 12, 8 553-63). No specific endogenous ligand for ERBB2 has been identified, so it is assumed that it usually signals through heterodimerization (Sergina, Natalia V et al., Nature, Vol. 445, 7126 (2007): 437-41). ERBB3 can be activated by binding to its ligands. These ligands include, but are not limited to, neuregulin (NRG) (also known as heregulin (HRG)).

[0042] ERBB1 is known by several synonyms, the most common of which is EGFR. EGFR has an extracellular domain (ECD) composed of four subdomains, two of which are involved in ligand binding and the other two are involved in homodimerization and heterodimerization. EGFR integrates extracellular signals from a variety of ligands to produce different intracellular responses. EGFR is associated with several human epithelial malignancies, notably breast cancer, bladder cancer, non-small cell lung cancer, lung cancer, colon cancer, ovarian head and neck cancer, and brain cancer. Activating mutations in this gene and overexpression of the receptor and its ligands have been found to produce an autocrine activation cycle. This receptor tyrosine kinase (RTK) has been widely used as a target for cancer therapy. Small molecule inhibitors against RTK and monoclonal antibodies (mAbs) (monospecific bivalent) against the extracellular ligand binding domain have been developed and have achieved several clinical successes to date. The database accession number for the human EGFR protein and its encoding gene is (GenBank NM_005228.3). The accession number is provided primarily to provide a means of further identifying the EGFR protein being targeted, while the actual sequence of the EGFR protein to which the antibody binds may vary, for example due to mutations in the encoding gene, such as occur in certain cancers or similar conditions.

[0043] The term "ERBB2" as used herein refers to the protein encoded by the ERBB2 gene in humans. Alternative names for the gene or protein include: CD340; HER2; HER-2 / neu; MLN 19; NEU; NGL; TKR1. The ERBB2 gene is often referred to as HER2 (from human epidermal growth factor receptor 2). When ERBB2 is mentioned herein, the reference is to human ERBB2. An antibody comprising an ERBB2 antigen binding site binds to human ERBB2. Due to the sequence and tertiary structure similarities between human and other mammalian heterologs, the ERBB2 antigen binding site may also bind to this heterolog, but not necessarily. The database accession numbers for the human ERBB2 protein and its encoding gene are (NP_001005862.1, NP_004439.2NC_000017.10NT_010783.15NC_018928.2). The accession number is provided primarily to provide a method for further identifying the ERBB2 protein as a target, while the actual sequence of the ERBB2 protein to which the antibody binds may vary, for example due to mutations in the encoding gene, such as those that occur in certain cancers or similar situations. The ERBB2 antigen binding site binds to ERBB2 and its various variants, such as variants expressed by some ERBB2-positive tumor cells. The antigen binding site that binds to ERBB2 preferably binds to domain I of ERBB2.

[0044] As used herein, the term "ERBB3" refers to the protein encoded by the ERBB3 gene in humans. Alternative names for the gene or protein include: HER3; LCCS2; MDA-BF-1; c-ERBB3; c-ERBB3; ERBB3-S; p180-ERBB3; p45-sERBB3; and p85-sERBB3. When ERBB3 is referred to herein, the reference is to human ERBB3. Antibodies comprising an ERBB3 antigen binding site bind to human ERBB3. Due to the sequence and tertiary structure similarities between human and other mammalian heterologs, the ERBB3 antigen binding site may also bind to such heterologs, but not necessarily. The database accession numbers for the human ERBB3 protein and its encoding gene are NP_001973.2 and NC_000012.11, which include the genomic location of the ERBB3 gene on chromosome 12 (56473892 to 56497289). The accession number is provided primarily to provide a method for further identifying the ERBB3 protein as a target, while the actual sequence of the ERBB3 protein to which the antibody binds may vary, for example due to mutations in the encoding gene, such as those that occur in certain cancers or similar situations. The ERBB3 antigen binding site binds to ERBB3 and its various variants, such as variants expressed by some ERBB3-positive tumor cells. The antigen binding site that binds to ERBB3 preferably binds to domain III of ERBB3.

[0045] When referring to ERBB1, ERBB2 or ERBB3 or alternative names thereof, reference is made to human ERBB1, ERBB2 or ERBB3. The antibodies referred to herein bind to ERBB1, ERBB2 or ERBB3 as well as many mutated ERBB1, ERBB2 or ERBB3 proteins, such as those found in cancer.

[0046] The present invention provides a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3, for use in a method of treating castration-resistant prostate cancer in an individual. The method comprises administering to the individual a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3. Optionally, the treatment method also comprises the use of an androgen receptor axis-targeting agent.

[0047] The present invention provides a method for treating an individual with castration-resistant prostate cancer, the method comprising administering to the individual a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the method comprises screening an individual with castration-resistant prostate cancer or an individual suspected of having castration-resistant prostate cancer for treating castration-resistant prostate cancer. Optionally, the method further comprises administering to the individual an androgen receptor axis-targeting agent.

[0048] The present invention provides the use of a bispecific antibody comprising an antigen binding site that binds or can bind to the extracellular portion of ERBB2 and an antigen binding site that binds or can bind to the extracellular portion of ERBB3 for the manufacture of a medicament for treating castration-resistant prostate cancer in an individual. Optionally, the treatment or use further comprises the use of an androgen receptor axis-targeting agent.

[0049] Endocrine and metabolic outcomes represent the main side effects associated with the safety of hormonal therapy for prostate cancer. For example, treatment with abiraterone acetate can result in mineralocorticoid excess, hypokalemia, hypertension, elevated liver function tests, insulin resistance, and hyperglycemia. Enzalutamide is known to induce or worsen hypertension and is associated with an increase in falls and fractures in elderly patients. Therefore, the safety issues associated with abiraterone acetate and enzalutamide are expected to have limited overlap toxicity with zenoculumab, and the well-tolerated safety profile of zenoculumab makes it an excellent candidate for combination therapy in this advanced and pre-treated elderly patient population. Continuous blockade of CRPC using AR signaling inhibitors while simultaneously blocking the HER3 / NRG1 resistance signaling pathway may treat patients after the failure of next-generation AR drugs. Disclosed herein is a method for treating castration-resistant prostate cancer in an individual while continuing to treat CRPC with an androgen-targeted agent while simultaneously using an antibody comprising an antigen binding site that binds to domain III of the extracellular portion of ERBB3, or an antibody comprising an antigen binding site that binds to domain III of the extracellular portion of ERBB3 and an antigen binding site that binds to domain I of the extracellular portion of ERBB2.

[0050] Alternatively, the castration-resistant prostate cancer has deteriorated after receiving previous cancer treatment. Such previous treatment, also referred to as anticancer therapy or treatment, optionally, includes androgen receptor axis-targeting agent. Alternatively, cancer has deteriorated after previously treating with androgen receptor antagonists (such as second-generation androgen receptor antagonists). Alternatively, after previously treating with first-generation androgen receptor antagonists (such as flutamide, bicalutamide or nilutamide), or second-generation androgen receptor antagonists (such as apalutamide, darolutamide or enzalutamide), or androgen receptor antagonists known to those of ordinary skill in the art (such as proxalutamide, BMS-641988, TQB3720, SHR3680 or TRC-253), cancer has deteriorated. Optionally, the cancer has progressed following prior treatment with enzalutamide.

[0051] Optionally, the castration-resistant prostate cancer is metastatic castration-resistant prostate cancer (mCRPC).

[0052] Optionally, the treatment method comprising the use or administration of a bispecific antibody of the invention further comprises the use or administration of an androgen receptor axis-targeting agent.

[0053] Thus, optionally, the cancer has worsened after previous treatment with an androgen receptor axis-targeting agent. Alternatively, if the cancer has worsened after previous treatment with an androgen receptor antagonist, the use of the bispecific antibody in the treatment method of the present invention further comprises the use of an androgen receptor antagonist. Alternatively, if the cancer has worsened after previous treatment with an androgen receptor antagonist, the method of treating with the bispecific antibody according to the content of the present invention further comprises administering an androgen receptor antagonist. Thus, a combined use can be foreseen, wherein a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3 can be used with an androgen receptor antagonist during the same treatment period. Thus, optionally, the cancer has worsened after previous treatment with an androgen receptor antagonist, and the method of treating with the antibody further comprises the use of an androgen receptor antagonist.

[0054] Optionally, the androgen receptor antagonist used in the previous cancer treatment is the same as the androgen receptor antagonist used in the treatment method of the bispecific antibody combination of the present invention. Optionally, the androgen receptor antagonists used in the previous cancer treatment and used in combination with the bispecific antibody of the present invention are apalutamide, darolutamide or enzalutamide. Optionally, the androgen receptor antagonists used in the previous cancer treatment and used in combination with the antibodies of the present invention are enzalutamide. Therefore, optionally, the present invention provides a combination therapy or combination therapy, wherein the bispecific antibody such as Zenokuzumab comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3 is used together with an androgen receptor antagonist (such as enzalutamide).

[0055] Optionally, the antibodies of the invention are combined with an androgen receptor antagonist, including flutamide, bicalutamide, nilutamide, a second generation androgen receptor antagonist such as apalutamide, darolutamide or enzalutamide, or an androgen receptor antagonist known to those of ordinary skill in the art such as proxalutamide, BMS-641988, TQB3720, SHR3680 or TRC-253.

[0056] Optionally, enzalutamide is administered at a daily dose of 160 mg. Optionally, enzalutamide is administered at a daily dose of 160 mg and the bispecific antibody of the invention is administered once every two weeks in an amount of 750 mg. Optionally, the bispecific antibody is zenoculumab. Thus, the treatment of the individual comprises the administration of both enzalutamide and zenoculumab. Optionally, enzalutamide used in a previous cancer treatment and further included in the treatment methods of the invention is administered at a daily dose of 160 mg.

[0057] Optionally, the cancer has worsened after previous treatment with an androgen synthesis inhibitor. Optionally, if the cancer has worsened after previous treatment with an androgen synthesis inhibitor, the use of the bispecific antibody in the treatment method of the present invention further comprises the use of an androgen synthesis inhibitor. Optionally, if the cancer has worsened after previous treatment with an androgen synthesis inhibitor, the treatment method using the bispecific antibody according to the present invention further comprises the administration of an androgen synthesis inhibitor. Therefore, a combined use can be foreseen, wherein a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3 can be used with an androgen synthesis inhibitor during the same treatment. Therefore, optionally, the cancer has worsened after previous treatment with an androgen synthesis inhibitor, and the method of treating with the antibody further comprises the use of an androgen synthesis inhibitor.

[0058] Optionally, the androgen synthesis inhibitor used in the previous cancer treatment is the same as the androgen synthesis inhibitor used in the treatment method of the bispecific antibody combination of the present invention. Optionally, the androgen synthesis inhibitor used in the previous cancer treatment and the androgen synthesis inhibitor used in the treatment method of the bispecific antibody combination of the present invention are both abiraterone acetate, such as Thus, optionally, the present invention provides a combination therapy or combination treatment wherein the bispecific antibody comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3, such as zenocurizumab, is administered during the same treatment period with an androgen synthesis inhibitor (such as abiraterone acetate, e.g. )

[0059] Alternatively, the antibody of the invention is combined with an androgen synthesis inhibitor such as abiraterone acetate. Alternatively, the antibody is a bispecific antibody disclosed herein. Alternatively, the abiraterone acetate used in a previous cancer treatment and further included in the treatment method of the invention is administered at a daily dose of 1000 mg.

[0060] Alternatively, abiraterone acetate such as Administered at a daily dose of 1000 mg. Optionally, abiraterone acetate is used in combination with 5 mg of prednisone administered orally twice daily. Optionally, abiraterone acetate is administered at a daily dose of 1000 mg, such as The bispecific antibody of the invention is administered in an amount of 750 mg once every two weeks. Optionally, the bispecific antibody is Zenoculumab. Thus, the treatment of the individual comprises administering both abiraterone acetate and Zenoculumab during the same treatment period.

[0061] In addition, the individual may have received other prior treatments for prostate cancer, including taxane-based chemotherapy, such as docetaxel or cabazitaxel. Additionally or alternatively, the individual may also have received prior treatment with sipuleucel-T or radiopharmaceuticals, such as radium 223 or LU 177.

[0062] Radiopharmaceuticals or medical radioactive compounds are a group of drugs that contain radioactive isotopes. Examples include radium 223 and lutetium (177Lu) oxytreptide. Lutium (177Lu) oxytreptide (International Nonproprietary Name or INN) or 177 LuDOTA-TATE, trade name It is a chelate complex of radioactive isotope of lutetium and DOTA-TATE, used for peptide receptor radionuclide therapy.

[0063] As used herein, the terms "subject" and "patient" are used interchangeably and refer to mammals, such as humans, mice, rats, hamsters, guinea pigs, rabbits, cats, dogs, monkeys, cows, horses, pigs, and the like (e.g., patients with cancer, such as human patients). Optionally, the individual is a human individual. In this article, the individual suffers from castration-resistant prostate cancer, or is at risk of developing castration-resistant prostate cancer.

[0064] As used herein, castration-resistant prostate cancer (CRPC) refers to an individual with prostate cancer that has progressed after prior prostate treatment and whose testosterone levels are equal to or lower than the level detected after the individual undergoes castration (also referred to as "castration testosterone level"). Optionally, the individual exhibits an increase in serum prostate-specific antigen while receiving androgen deprivation therapy (ADT), and / or has developed new metastases and / or worsening of existing metastases. Optionally, an individual with CRPC has a serum testosterone level of <50 ng / dL.

[0065] Castration is used to suppress the production of androgens, such as testosterone, which is a method of treating prostate cancer to reduce circulating androgen levels. Castration is usually achieved by surgery (orchiectomy) or chemical means. Such chemical means include androgen deprivation therapy (ADT), chemotherapy (including but not limited to docetaxel), Cabazitaxel ), androgen receptor axis-targeted (ARAT) agents, androgen synthesis inhibitors, and (second generation) androgen receptor antagonists. Examples include, but are not limited to, abiraterone, enzalutamide, apalutamide, and darolutamide. More examples of AR antagonists are included in Table 1.

[0066] Table 1. Development history of AR antagonists for prostate cancer

[0067]

[0068] Alternatively, castration-resistant prostate cancer is a cancer after receiving a series of second-generation hormone agents for the treatment of castration-resistant prostate cancer. Alternatively, castration-resistant prostate cancer is a cancer that worsens after receiving no more than two second-generation hormone agents for the treatment of castration-resistant prostate cancer. Such second-generation hormone agents include but are not limited to androgen receptor antagonists (including but not limited to enzalutamide) or androgen synthesis inhibitors (including but not limited to abiraterone).

[0069] Optionally, the individual to be treated exhibits an increased prostate-specific antigen (PSA) level, which is defined as two increases in PSA reaching a minimum value of ≥1 ng / mL before starting treatment. Optionally, the increase exceeds the previous reference value. An increase in prostate-specific antigen (PSA) levels generally refers to an increase in PSA of more than 25% and >2 ng / ml above the lowest point, confirmed by the progression of two time points at least three weeks apart.

[0070] Alternatively, the patient may have discontinued dosing of an androgen receptor axis-targeting agent (such as abiraterone or enzalutamide) for more than 14 days, followed by a documented increase in PSA levels upon resumption of the agent.

[0071] The term "androgen receptor axis-targeting agent" herein includes androgen synthesis inhibitors and androgen receptor antagonists. Therefore, the androgen receptor axis-targeting agent referred to herein prevents, blocks or reduces the signal transduction activity of the androgen receptor. The activity of the androgen receptor axis is related to the deterioration of castration-resistant prostate cancer. The effect on the androgen receptor axis can be achieved using androgen synthesis inhibitors (such as abiraterone acetate), which affect serum androgen levels (such as testosterone) so that androgen receptor activity is prevented, blocked or reduced. Alternatively, the effect on the androgen receptor axis can be achieved using androgen receptor antagonists such as enzalutamide to prevent, block or reduce the binding of ligands to androgen receptors and their activation.

[0072] At the start of treatment, at least one, more than one or all of the following inclusion factors IF1-IF7 are applicable to the individual to be treated. Alternatively, the individual contains or meets all inclusion factors IF1-IF7.

[0073] IF1. Age equal to or greater than 18 years old.

[0074] IF2. The Eastern Cooperative Oncology Group (ECOG) daily performance status is 0 or 1.

[0075] IF3. Life expectancy is equal to or greater than 12 weeks.

[0076] IF4. At least three weeks have passed since any major surgery, completion of radiation therapy, completion of all prior systemic anticancer therapy, or at least five half-lives if the prior therapy was a single-agent small molecule therapeutic, and adequate recovery from any acute toxicity of the prior therapy to a National Cancer Institute (NCI)-Common Terminology Criteria for Adverse Events (CTCAE) v.5.0 grade equal to or less than 1, except in the case of alopecia or neuropathy. Such single-agent small molecule therapeutic agents may be flutamide, ketoconazole, and similar drugs.

[0077] IF5. Left ventricular ejection fraction (LVEF) equal to or greater than 50% as measured by cardiac ultrasound (ECHO) or multi-channel cardiac function imaging (MUGA).

[0078] IF6. Adequate organ function depends on:

[0079] IF6.1. Absolute neutrophil count equal to or greater than 1.5 × 10 9 / L.

[0080] IF6.2. Hemoglobin level equal to or greater than 9 g / dL.

[0081] IF6.3. Platelet count equal to or greater than 100 × 10 9 / L.

[0082] IF6.4. Serum calcium is within normal range (or corrected with supplements).

[0083] IF6.5. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) equal to or less than 2.5× upper limit of normal (ULN), but if liver malignancy is involved, ALT / AST equal to or less than 5× ULN.

[0084] IF6.6. Total bilirubin level equal to or less than 1.5×ULN, except in the case of Gilbert disease where the total bilirubin is equal to or less than 3×ULN.

[0085] IF6.7. Estimated glomerular filtration rate according to the Cockroft-Gault formula is more than 30 mL / min, and

[0086] IF6.8. Serum albumin exceeds 3.0 g / dL.

[0087] IF7. Formalin-fixed paraffin-embedded (FFPE) tumor specimens are available. Specimens can be collected from the beginning as archived FFPE tumor samples, preferably within 2 years after the start of treatment.

[0088] Alternatively, all values ​​measured for organ function based on IF6 have an upper limit observed in healthy individuals.

[0089] Optionally, the individual to be treated comprises one or more factors selected from IF1-IF7. Optionally, the individual to be treated comprises factors IF2, IF3, IF5 and IF6. Optionally, the individual to be treated comprises all factors IF1-IF7.

[0090] Here, the ECOG daily physical status score is defined as follows: 0: Fully active, able to perform all pre-illness manifestations without restriction. 1: Vigorous physical activity is limited, but can walk and can perform light or sedentary work, such as light housework, office work. 2: Able to walk and can take care of themselves, but unable to perform any work activities. About more than 50% of waking time. 3: Only limited self-care can be performed, and more than 50% of waking time is confined to bed or chair. 4: Complete disability. Unable to perform any self-care. Completely confined to bed or chair. 5: Death.

[0091] Optionally, the individual to be treated has histologically confirmed prostate adenocarcinoma, optionally without neuroendocrine differentiation or small cell features.

[0092] Optionally, the individual to be treated has metastatic disease as documented by at least 2 bone lesions on a whole body bone scan, or soft tissue disease documented by computed tomography (CT) scan / magnetic resonance imaging (MRI).

[0093] Optionally, the individual to be treated has a serum testosterone level of ≤1.73nmol / L (≤50ng / dL) prior to the start of treatment. Optionally, the individual to be treated is receiving androgen deprivation therapy. Optionally, the individual to be treated is receiving androgen deprivation therapy and has a serum testosterone level of ≤1.73nmol / L (≤50ng / dL) before treatment. Therefore, optionally, a step of determining the serum testosterone level of a sample obtained from the individual is performed prior to the treatment method. Thereafter, if the serum testosterone level is ≤1.73nmol / L (≤50ng / dL), the individual may be selected for treatment. The PCWG3 guidelines recommend the use of a testosterone detection assay with a sensitivity of 1 to 2ng / dL when determining serum testosterone levels, and such detection assays are readily available.

[0094] Optionally, prior treatment with an androgen receptor axis-targeting agent was initiated at least 90 days or at least 118 days prior to initiation of treatment with the present invention. A maximum of 30 days of interruption in dosing is permitted within the at least 90 or 118 days.

[0095] Optionally, the individual to be treated has CRPC or CRPC disease progression according to Prostate Cancer Working Group 3 (PCWG3) criteria. Optionally, CRPC disease progression is established according to at least one or more of the following criteria:

[0096] 1. An increase in prostate-specific antigen (PSA) level, defined as two increases in PSA from the previous reference value, reaching a minimum value of ≥1 ng / mL before the start of treatment, provided that if the patient has an interruption in the administration of an androgen receptor axis-targeted agent (such as abiraterone or enzalutamide) for more than 14 days, an increase in PSA level is documented after the resumption of the agent.

[0097] 2. Worsening of soft tissue disease as defined by RECIST v1.1.

[0098] 3. Deterioration of previously normal (<10 mm) lymph nodes, as determined by short-axis growth ≥5 mm.

[0099] 4. Whole body bone scan showing two or more new lesions was defined as bone disease worsening.

[0100] An increase in prostate-specific antigen (PSA) or a level of increase determined as a PSA increase of greater than 25% and >2 ng / ml above the lowest point, confirmed by exacerbation at two time points at least three weeks apart. (See Scher et al., 2016, Trial Design and Objectives for Castration-Resistant Prostate Cancer: Updated Recommendations From the Prostate Cancer Clinical Trials Working Group 3. "J Clin Oncol 34 (12): 1402-1418.).

[0101] Optionally, the individual to be treated is receiving a stable dose of a bisphosphonate or denosumab for a period of at least 4 weeks. The bisphosphonate or denosumab may be provided for maintaining or improving bone health.

[0102] Optionally, the individual to be treated is able to swallow oral medications and does not have a gastrointestinal disorder (eg, malabsorption, resection) that is thought to compromise intestinal absorption.

[0103] Optionally, provide a premedication with:

[0104] -Aracetamol / acetaminophen 1000 mg PO or IV.

[0105] -Dexchlorpheniramine 5 mg IV (or other anti-H1 equivalent, PO or IV)

[0106] -Dexamethasone 10 mg IV (or equivalent, PO or IV). Corticosteroids may be administered prior to Cycle 1 Day 1 administration if needed and should be used for subsequent injections at the investigator's discretion to manage infusion-related reactions (IRRs).

[0107] -H2 antagonists may be administered at the investigator's discretion.

[0108] Optionally, the individual to be treated has not received more than two second generation hormonal agents for metastatic disease. Such agents include abiraterone and enzalutamide. Optionally, the individual to be treated has not received more than two systemic chemotherapy for metastatic disease. Such chemotherapy includes docetaxel Cabazitaxel Optionally, the individual to be treated has not previously received anti-HER3 -directed therapy.

[0109] Optionally, the subject shows clinical efficacy after receiving anti-CRPC treatment according to the present invention, which is based on PCWG3-modified RECIST v 1.1 criteria. Optionally, the patient exhibits progression-free survival (PFS), non-deteriorating disease (Non-PD), no evidence of disease (NED), stable disease (SD), partial response (PR) or complete response (CR), according to the PCWG3 modified version of RECIST v1.1 criteria. Optionally, the patient exhibits disease control of lymph nodes, visceral tissues and / or bone tissues that can be measured on radiographs, according to the PCWG3 or PCWG3 modified version of RECIST v1.1 criteria. Optionally, the individual exhibits the clinical efficacy after receiving treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3). Optionally, the treatment method further comprises administering to the individual an androgen receptor axis-targeting agent, such as abiraterone or enzalutamide.

[0110] The terms "treat, treating, treatment" as used herein refer to any type of intervention or process on an individual, or the administration of an active agent or combination of active agents to an individual, with the purpose of curing or improving a disease or its symptoms. This includes reversing, alleviating, improving, inhibiting or slowing down symptoms, complications, symptoms or biochemical indicators associated with the disease, and preventing the onset, aggravation, development, severity or recurrence of symptoms, complications, symptoms or biochemical indicators associated with the disease.

[0111] Any method disclosed herein in connection with any use of the methods of treatment of the present invention is equally applicable to the methods of treatment of the present invention, and vice versa.

[0112] Any method disclosed herein in connection with any use of the therapeutic method of the present invention is equally applicable to any use in manufacturing the therapeutic medicament of the present invention, and vice versa.

[0113] Any method disclosed herein in connection with the treatment method of the present invention is equally applicable to any use in manufacturing the therapeutic drug of the present invention, and vice versa.

[0114] As used herein, "effective treatment" or "positive therapeutic response" refers to treatment that produces a beneficial effect, such as an improvement in at least one symptom of a disease or disorder, such as cancer. The beneficial effect can take the form of an improvement relative to a baseline, including an improvement relative to a measurement or observation made before treatment according to the method was initiated. For example, a beneficial effect can take the form of slowing, stabilizing, halting, or reversing the progression of a cancer in a subject at any clinical stage, as evidenced by a reduction or elimination of clinical or diagnostic symptoms of the disease or markers of cancer. An effective treatment can, for example, reduce tumor size, reduce the presence of circulating tumor cells, reduce or prevent tumor metastasis, slow or stop tumor growth, and / or prevent or delay tumor recurrence or recurrence.

[0115] The terms "therapeutic amount" or "effective amount" are used interchangeably herein and refer to an amount of an agent or combination of agents that provides a desired biological, therapeutic and / or preventive result. The result may be reduction, amelioration, alleviation, mitigation, delay and / or alleviation of one or more signs, symptoms or causes of a disease, or any other desired change in a biological system. Alternatively, a therapeutic amount is an amount sufficient to delay tumor development. Alternatively, a therapeutic amount is an amount sufficient to prevent or delay tumor recurrence.

[0116] The therapeutic amount of the drug or composition can: (i) reduce the number of cancer cells; (ii) reduce the size of tumors; (iii) inhibit, delay, slow down and possibly prevent cancer cells from infiltrating surrounding organs to a certain extent; (iv) inhibit tumor metastasis; (v) inhibit tumor growth; (vi) prevent or delay the occurrence and / or recurrence of tumors; and / or (vii) alleviate one or more symptoms associated with cancer to a certain extent.

[0117] The therapeutic amount may vary according to factors such as the disease state, age, sex, and weight of the individual being treated, and the ability of the agent or combination of agents to elicit a desired response in the individual.

[0118] A therapeutic amount can be administered in one or more administrations.

[0119] A therapeutic amount also includes an amount that balances any toxic or detrimental effects of the agent or combination of agents against the therapeutically beneficial effects.

[0120] It is noteworthy that the loss of tumor suppressor genes is particularly common in CRPC and is associated with aggressive disease and poor prognosis. In order to effectively inhibit tumor growth with bispecific antibodies disclosed herein (such as Zenokuzumab) or ERBB3-specific antibodies disclosed herein, a complete signaling pathway downstream of the PI3K pathway may be necessary. Therefore, optionally, the castration-resistant prostate cancer to be treated does not have PTEN loss, or does not have PTEN defects. Optionally, the cancer treated according to the present invention is characterized by having a wild-type PTEN state. Optionally, the cancer does not have PTEN loss. Optionally, the cancer is PTEN wild type. Optionally, cancer does not show PTEN loss. Without being bound by theory, optionally, before the treatment disclosed herein begins, it is useful to classify individuals based on PTEN status, because cancers with appropriate PTEN status can benefit more from the treatment. Individuals whose PTEN status has been determined to be wild-type PTEN or not having PTEN loss can be selected for treatment disclosed herein, or classified as eligible for the treatment.

[0121] Alternatively, the castration-resistant prostate cancer treated according to the present invention shows PTEN deficiency or PTEN defect.Alternatively, the cancer treated according to the present invention is characterized in that there is a PTEN deficiency state.Alternatively, the cancer has PTEN deficiency.Alternatively, the cancer is not PTEN wild type.Alternatively, the cancer shows PTEN deficiency.Not bound by theory, alternatively, before the treatment disclosed herein begins, it is useful to classify individuals based on PTEN status, because the cancer with appropriate PTEN status can benefit more from the treatment.Can select its PTEN status to be determined as non-PTEN wild type or have PTEN deficiency individuality to carry out the treatment disclosed herein, or be classified as eligible to receive the treatment.

[0122] PTEN status can be determined by methods known to those of ordinary skill in the art, and any suitable method can be used in combination with a therapeutic method or in combination with an antibody of the invention, including a combination therapy as described herein. Optionally, PTEN status is determined using IHC. Optionally, PTEN status is determined using a liquid specimen assay.

[0123] For example, a commercially available PTEN gene test can be used to determine the PTEN status of a specimen or blood sample cell. A variety of methods can be used, and many methods are known in the art. One method is to use primers that span PTEN cDNA or genomic DNA for PCR amplification, followed by sequencing of the amplified nucleotide molecules. This can be done for mutations that are known to occur and affect PTEN activity. New mutations can also be easily detected by techniques known to those of ordinary skill in the art, including by next-generation DNA or RNA sequencing. Other methods for determining PTEN status are by ELISA.

[0124] Nucleic acid-based techniques can be used to determine PTEN status, including allele-specific RNA-based methodologies, including RT-PCR, real-time PCR, transcriptome analysis, anchored multiplex PCR, nCounter, FISH, DNA-based methodologies including next-generation sequencing (NGS) based on heterozygous capture, amplicon-based NGS, and other commercially available technologies. In addition, PTEN loss can be determined using protein-based assays, such as immunostaining, IHC, FISH, or similar techniques. To date, there are robust clinical assays that reproducibly measure PTEN protein and gene loss using circulating tumor cells in diagnostic tissue specimens and plasma using immunohistochemistry and fluorescence in situ hybridization. In particular, the IHC process has been successfully validated on the Ventana Benchmark platform in a Clinical Laboratory Improvement Amendments-certified laboratory, with high interobserver reproducibility of the scoring system.

[0125] An example of a commercial kit for establishing PTEN status is the use of It is an analytically validated tissue comprehensive genomic composition analysis panel, including TMB, MSI status, and PD-L1 IHC. The Guardant360 TissueNext report contains 84 genes. This kit can perform point mutation (SNV) and deletion variation (Indel) genotyping, amplification of 20 genes, and fusion identification of 12 genes for 84 genes (including PTEN). Another example of a commercial kit that can be used to establish PTEN status is the Roche Ventana Optiview kit DAB, which uses the SP218 PTEN antibody.

[0126] Therefore, the present invention also provides a method for selecting an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, selecting the individual for said treatment.

[0127] Alternatively, the present invention provides a method for determining whether an individual with castration-resistant prostate cancer is likely to respond to treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) selecting a sample that does not exhibit PTEN loss, thereby establishing that the individual from whom the sample is derived is likely to respond to the treatment.

[0128] Alternatively, the present invention provides a method for classifying an individual with castration-resistant prostate cancer based on PTEN status prior to treatment with a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3, the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, classifying the individual from whom the sample is derived as eligible for said treatment.

[0129] The present invention also provides a method for selecting an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample exhibits PTEN loss, selecting the individual for said treatment.

[0130] Alternatively, the present invention provides a method for establishing whether an individual with castration-resistant prostate cancer is likely to respond to treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) selecting a sample that exhibits PTEN loss, thereby establishing that the individual from whom the sample is derived is likely to respond to said treatment.

[0131] Alternatively, the present invention provides a method for classifying an individual with castration-resistant prostate cancer based on PTEN status prior to treatment with a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3, the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample exhibits PTEN loss, classifying the individual from whom the sample was derived as eligible for said treatment.

[0132] Optionally, IHC is used to determine PTEN loss or PTEN status. In another aspect, a liquid sample assay including DNA sequencing is used to determine PTEN status.

[0133] Alternatively, the cancer or individual to be treated by the present invention does not have a mutation in an oncogenic driver. Alternatively, the cancer or individual does not have a mutation in an oncogenic driver on the PI3K, AKT, mTOR pathway. Alternatively, the cancer or individual does not have an upregulation of the pathway. Alternatively, the cancer or individual does not have a mutation in any one of EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET, and ROS1. Alternatively, the cancer or individual does not have a mutation in a known tumor-related gene or a protein encoded therefrom such as EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET, and ROS1.

[0134] Optionally, the individual's cancer is tested by next generation sequencing (e.g., DNA, RNA or whole transcriptome), after which the cancer or individual is screened for treatment with a bispecific antibody (which comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3) using a method comprising the following steps: a) determining the presence of oncogenic driver mutations, optionally, mutations that regulate the PI3K, AKT and / or mTOR pathways, in a sample obtained from the individual; b) if the sample lacks the presence of oncogenic driver mutations, optionally, mutations that regulate PI3K, AKT and / or mTOR, classifying the individual from whom the sample was derived as eligible for said treatment.

[0135] Optionally, the individual's cancer is tested by next generation sequencing (e.g., DNA, RNA or whole transcriptome), after which the cancer or individual is screened for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3), using a method comprising the following steps: a) determining the presence of oncogenic driver mutations, optionally mutations in EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1, in a sample obtained from the individual; b) if the sample lacks the presence of oncogenic driver mutations, optionally mutations in EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1, classifying the individual from whom the sample was derived as eligible for said treatment.

[0136] Optionally, a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3 is used to screen CRPC or individuals having CRPC for treatment, using a method comprising the following steps: a) determining the presence of an oncogenic driver mutation in a sample obtained from the individual's CRPC, optionally, the mutation modulates the PI3K, AKT and / or mTOR pathway; b) if the sample lacks the presence of an oncogenic driver mutation, optionally, a mutation that modulates PI3K, AKT and / or mTOR, classifying the individual from whom the sample was derived as eligible for said treatment.

[0137] Optionally, a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3 is used to screen CRPC or individuals with CRPC for treatment, using a method comprising the following steps: a) determining the presence of oncogenic driver mutations, optionally mutations in EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1, in a sample obtained from the individual; b) if the sample lacks the presence of oncogenic driver mutations, optionally mutations in EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1, classifying the individual from whom the sample was derived as eligible for said treatment.

[0138] Optionally, the sample obtained from the individual is a sample taken from a tumor or cancer before the anti-CRPC treatment of the present invention. Optionally, the sample obtained from the individual is a sample containing tumor or cancer cells from a tumor or cancer suffered by the individual to be treated. Optionally, the sample taken from the tumor or cancer is obtained before starting the anti-CRPC treatment of the present invention.

[0139] As used herein, the term "antigen binding site" refers to a site derived from and preferably present on a bispecific antibody that is capable of binding to an antigen. Antigen binding sites are typically formed by and present in the variable domains of an antibody. The variable domains contain the antigen binding site. The antigen binding site can bind to an antigen under normal physiological conditions. This is also often referred to as the antigen binding site "binding" the antigen.

[0140] In one embodiment, the antibody variable domain comprises a heavy chain variable region (VH) and a light chain variable region (VL). The antigen binding site may be present in the combined VH / VL variable domain, or only in the VH region or only in the VL region. When the antigen binding site is present in only one of the two regions of the variable domain, the other variable region may contribute to the folding and / or stability of the combined variable region, but does not significantly contribute to the binding to the antigen.

[0141] As used herein, antigen binding refers to the typical binding ability of an antibody to its antigen. An antibody comprising an antigen binding site that binds to ERBB2 binds at least 100-fold less to the cognate receptors ERBB1 and ERBB4 of the same species under otherwise identical conditions. An antibody comprising an antigen binding site that binds to ERBB3 binds to ERBB3 and does not bind to the cognate receptors ERBB1 and ERBB4 of the same species under otherwise identical conditions.

[0142] Considering that the ERBB family is a family of cell surface receptors, its binding is usually assessed on cells expressing the receptors. The binding of an antibody to an antigen can be assessed in a variety of ways. One method is to place the antibody and the antigen (preferably a cell expressing the antigen) together, remove the unbound antibody (preferably by a washing step), and detect the bound antibody by a labeled antibody that binds to the bound antibody.

[0143] The binding of an antibody to an antigen is usually mediated by the complementary regions of the antibody, and the specific three-dimensional structure of the antigen and the variable domain, which allows the two structures to fit together precisely (similar to the interaction of a lock and key), as opposed to random, non-specific adhesion of the antibody. Since antibodies usually recognize an epitope of an antigen, and this epitope may also be present in other compounds, the antibodies of the present invention that bind to ERBB2 and / or ERBB3 may also recognize other proteins if the other compounds contain the same epitope. Therefore, the term "binding" does not exclude the binding of an antibody to another protein or proteins containing the same epitope. Such other proteins are preferably non-human proteins. The ERBB2 antigen binding site and the ERBB3 antigen binding site defined herein do not usually bind to other proteins on the cell membrane after birth, preferably in adults.

[0144] As used herein, the term "interfering with binding" means that the antibody is directed against an epitope on ERBB3, and the antibody competes with the ligand for binding to ERBB3. When the ligand has bound to ERBB3, the antibody can reduce ligand binding, displace the ligand, or it can at least partially prevent the ligand from binding to ERBB3, for example, by steric hindrance.

[0145] The term "antibody" as used herein means a protein molecule, preferably belonging to the immunoglobulin class of proteins, which contains one or more variable domains that can bind to an epitope on an antigen, wherein such domains are derived from the variable domains of an antibody or share sequence homology with the variable domains. Antibodies for therapeutic use are preferably as close as possible to the natural antibodies of the individual to be treated (e.g., human antibodies for human individuals). Antibody binding can be expressed in specificity and affinity. Specificity determines which antigen or epitope the binding domain specifically binds to. Affinity is a measure of the strength of binding to a specific antigen or epitope. Antibodies such as the bispecific antibodies of the present invention comprise the constant domain (Fc portion) of a natural antibody. The antibodies of the present invention are generally bispecific full-length antibodies, preferably human IgG subgroups. Preferably, the antibodies disclosed herein belong to the human IgG1 subgroup. Such antibodies have good ADCC properties, have a favorable half-life after administration to humans, and there is currently a CH3 modification technology that can provide modified heavy chains that preferentially form heterodimers rather than homodimers when co-expressed in selected cells.

[0146] The antibodies disclosed herein are preferably "full-length" antibodies. The term "full-length" is defined as comprising substantially complete antibodies, but they do not necessarily have all the functions of complete antibodies. For the avoidance of doubt, a full-length antibody comprises two heavy chains and two light chains. Each chain comprises a constant region (C) and a variable region (V), which can be further divided into CH1, CH2, CH3, VH and CL, VL domains (the appropriate amino acid sequences of each domain are as shown in FIG. Figure 1 and Figure 2). The antibody binds to the antigen via the variable domain contained in the Fab portion, and after binding, it can interact with the molecules and cells of the immune system via the constant domain (mainly via the Fc portion). The terms "VH / VL pair" and "VH / VL" are used interchangeably herein. The full-length antibodies of the present invention encompass antibodies in which mutations that provide the desired characteristics may exist. Such mutations should not be a majority deletion of any region. However, antibodies in which one or several amino acid residues are deleted without substantially changing the binding characteristics of the resulting antibody are included in the term "full-length antibody". For example, an IgG antibody may have 1-20 amino acid residues inserted, deleted, or a combination thereof in the constant region. For example, when an antibody itself has low ADCC activity, the ADCC activity of the antibody can be improved by slightly modifying the constant region of the antibody (Junttila, TT, K. Parsons et al. (2010). "Superior In vivo Efficacy of Afucosylated Trastuzumab in the Treatment of HER2-Amplified Breast Cancer." Cancer Research 70(11):4481-4489).

[0147] Full-length IgG antibodies are preferred because they have a better half-life and because of immunogenicity reasons, it is desirable to be as close to a fully autologous (human) molecule as possible. The antibodies disclosed herein are preferably bispecific IgG antibodies, preferably bispecific full-length IgG1 antibodies. IgG1 is preferred because of its long circulating half-life in humans. To prevent any immunogenicity in humans, it is preferred that the bispecific IgG antibody is human IgG1.

[0148] The term "bispecific" (bs) refers to one part of an antibody (as defined above) that binds to one epitope on an antigen and another part that binds to a different epitope. Different epitopes are usually present on different antigens. The heavy chain variable regions of bispecific antibodies are usually different from each other, while the light chain variable regions are preferably the same. Bispecific antibodies in which different heavy chain variable regions bind to the same or common light chain are also referred to as bispecific antibodies with a common light chain. The bispecific antibodies described herein usually comprise one variable domain that binds to ERBB2 and another variable domain that binds to ERBB3.

[0149] Preferred bispecific antibodies can be obtained by co-expressing two different heavy chains and a common light chain in a single cell. When a wild-type CH3 domain is used, the co-expression of two different heavy chains and a common light chain will produce three different species: AA, AB and BB. In order to increase the percentage of the desired bispecific product (AB), CH3 modification can be used, or in other words, heavy chains with compatible heterodimerization domains can be used, as defined below. Suitable compatible CH3 heterodimerization domains are as follows: Figure 2 d and 2e.

[0150] As used herein, the term "compatible heterodimerization domain" refers to a protein domain engineered such that the engineered domain A' will preferentially form heterodimers with the engineered domain B', and vice versa, while homodimerization between A'-A' and B'-B' is reduced.

[0151] The term "common light chain" refers to light chains that may be identical or have some amino acid sequence differences that do not affect the binding specificity of the full-length antibody. For example, non-identical but functionally equivalent light chains may be prepared or discovered, for example, by introducing and testing conservative amino acid changes, amino acid changes in regions that do not or only partially contribute to binding specificity when paired with a heavy chain, and the like. The terms "common light chain", "common VL", "single light chain", "single VL", with or without the term "rearrangement" are used interchangeably herein.

[0152] The common light chain (variable region) preferably has a germline sequence. Preferred germline sequences are light chain variable regions that are frequently used in human repertoires and have good thermodynamic stability, yield, and solubility. In a preferred embodiment, the light chain comprises a light chain region that contains Figure 1 The amino acid sequence of the IgVκ1-39*01 gene fragment shown is preferably a common light chain IGKV1-39 / jk1 with 0-10, preferably 0-5 amino acid insertions, deletions, substitutions, additions or combinations thereof. IgVκ1-39 is the abbreviation for immunoglobulin variable Kappa 1-39 gene. The gene is also referred to as immunoglobulin Kappa variable 1-39; IGKV139; or IGKV1-39. The external IDs of the gene are HGNC:5740; Entrez Gene:28930; Ensembl:ENSG00000242371. The variable region of IGKV1-39 is listed at Figure 1 The V zone can be combined with one of the five J zones. Figure 1Two preferred sequences of IgVκ1-39 in combination with the J region are described. The linked sequences are denoted IGKV1-39 / jk1 and IGKV1-39 / jk5; alternative names are IgVκ1-39*01 / IGJκ1*01 or IgVκ1-39*01 / IGJκ5*01 (nomenclature according to the IMGT database on the international webpage imgt.org).

[0153] Preferably, IgVκ1-39*01 comprising the light chain variable region is a germline sequence. More preferably, IGJκ1*01 or / IGJκ5*01 comprising the light chain variable region is a germline sequence. In a preferred embodiment, the light chain variable region of IGKV1-39 / jk1 or IGKV1-39 / jk5 is a germline sequence.

[0154] In a preferred embodiment, the light chain variable region comprises germline IgVκ1-39*01. In a preferred embodiment, the light chain variable region comprises a kappa light chain IgVκ1-39*01 / IGJκ1*01 or IgVκ1-39*01 / IGJκ5*01. In a preferred embodiment, IgVκ1-39*01 / IGJκ1*01. The light chain variable region preferably comprises a germline kappa light chain IgVκ1-39*01 / IGJκ1*01 or a germline kappa light chain IgVκ1-39*01 / IGJκ5*01, preferably a germline IgVκ1-39*01 / IGJκ1*01.

[0155] Those skilled in the art will recognize that "common" also refers to functional equivalents of light chains whose amino acid sequences are not identical. There are many variants of the light chain in which there are mutations (deletions, substitutions, additions) that do not substantially affect the formation of the functional binding region. The light chain may also be a light chain with 1-5 amino acid insertions, deletions, substitutions, or combinations thereof as described above.

[0156] Preferably, the first antigen binding site and the second antigen binding site both comprise a light chain variable region comprising a CDR1 having the sequence (RASQSISSYLN), a CDR2 having the sequence (AASSLQS) and a CDR3 having the sequence (QQSYSTPPT), wherein according to the KABAT numbering or according to the IMGT numbering system, the CDRs are QSISSY, AAS and QQSYSTPPT, respectively.

[0157] The antibodies disclosed herein can reduce the ligand-induced receptor function of ERBB3 on ERBB2 and ERBB3 positive cells. In the presence of excess ERBB2, ERBB2 / ERBB3 heterodimers can provide growth signals to expressing cells, in the absence of detectable ligands of ERBB3 chains in the heterodimers. The ERBB3 receptor function is referred to herein as the ligand-independent receptor function of ERBB3.

[0158] ERBB2 / ERBB3 heterodimers also provide growth signals to expressing cells in the presence of ERBB3 ligands. This ERBB3 receptor function is referred to herein as ligand-induced ERBB3 receptor function.

[0159] As used herein, the term "ERBB3 ligand" refers to a polypeptide that binds to and activates ERBB3. Examples of ERBB3 ligands include, but are not limited to, neuregulin 1 (NRG) and neuregulin 2, betacellulin, heparin-binding epidermal growth factor, and epiregulin. The term includes biologically active fragments of naturally occurring polypeptides and / or variants thereof.

[0160] Preferably, the ligand-induced receptor function of ERBB3 is the growth of ERBB2 and ERBB3 positive cells induced by ERBB3 ligand. In a preferred embodiment, the cells are MCF-7 cells ( HTB-22 TM );SKBR3( HTB-30 TM ) cells; NCI-87( CRL-5822 TM ) cells; BxPC-3-luc2 cells (Perkin Elmer 125058), BT-474 cells ( HTB-20 TM )JIMT 1 cells (DSMZ no.:ACC 589).

[0161] The ERBB2 protein contains several domains (see Landgraf, R Breast Cancer Res. 2007; 9(1): 202- Figure 1). This extracellular domain is referred to as domain I-IV. The positions that bind to each domain of the antigen binding site of the antibodies described herein have been pieced together. A bispecific antibody having an antigen binding site (first antigen binding site) of domain I or domain IV that binds ERBB2 (first antigen binding site) comprises a heavy chain variable region that, when combined with each light chain, maintains significant binding specificity and affinity for ERBB2. A bispecific antibody having an antigen binding site (first antigen binding site) of domain I or domain IV that binds ERBB2 (first antigen binding site) and an antigen binding site (second antigen binding site) that binds ERBB3 can more effectively reduce the ligand-induced receptor function of ERBB3 when compared to a bispecific antibody comprising an antigen binding site (first antigen binding site) that binds to another extracellular domain of ERBB2. A bispecific antibody comprising an antigen binding site (first antigen binding site) of domain I or domain IV that binds ERBB2 is preferred. Preferably, the antigen binding site binds to domain IV of ERBB2. Preferred antibodies comprise a first antigen binding site that binds domain I of ERBB2 and a second antigen binding site that binds domain III of ERBB3.

[0162] In a preferred embodiment, the antibody comprises an antigen binding site that binds to at least one amino acid of domain I of ERBB2, wherein the amino acid is selected from the group consisting of T144, T164, R166, P172, G179, S180 and R181, and a surface exposed amino acid residue located within about 5 amino acid positions of T144, T164, R166, P172, G179, S180 or R181.

[0163] In a preferred embodiment, the antibody preferably comprises an antigen binding site that binds to at least one amino acid of domain III of ERBB3, wherein the amino acid is selected from the group consisting of: R426 and an amino acid that is 1.5 to 2.5 Å away from R426 in the native ERBB3 protein. Surface exposed amino acid residues within.

[0164] Bispecific antibodies having an antigen binding site (first antigen binding site) that binds to ERBB2 and further comprising ADCC are more effective than other ERBB2 binding antibodies that do not have significant ADCC activity, especially in vivo. Therefore, bispecific antibodies that exhibit ADCC are preferred. By modifying the Fc region (by introducing amino acid substitutions) to bind to activated receptors with higher selectivity, bispecific antibodies with greater ability to mediate anti-cancer M a b Antibodies with desired cytotoxic activity.

[0165] One technique for enhancing the ADCC of an antibody is afucosylation. (See, e.g., Junttila, TT, K. Parsons et al. (2010). "Superior In vivo Efficacy of Afucosylated Trastuzumab in the Treatment of HER2-Amplified Breast Cancer." Cancer Research 70(11): 4481-4489). Therefore, further provided herein are bispecific antibodies that are afucosylated. Alternatively or additionally, a variety of other strategies may be used to achieve ADCC enhancement, including, for example, carbohydrate engineering and mutation induction, all of which seek to enhance the binding of Fc to the low-affinity activating FcγRIIIa and / or reduce the binding to the low-affinity inhibitory FcγRIIb.

[0166] There are several in vitro methods to determine the efficacy of antibodies or effector cells in inducing ADCC. These include the chromium 51 [Cr51] release assay, the europium [Eu] release assay, and the sulfur 35 [S35] release assay. Typically, a labeled target cell line expressing a particular surface-exposed antigen is incubated with an antibody specific for that antigen. After washing, effector cells expressing the Fc receptor CD16 are typically co-incubated with the antibody-labeled target cells. Lysis of the target cells is then typically measured by release of the intracellular marker, for example by scintillation counting or spectrophotometry.

[0167] Optionally, the antibodies disclosed herein are used in humans. Thus, optionally, the antibodies are human or humanized antibodies. Human tolerance to a polypeptide is controlled by many different aspects. Immunity, whether T cell mediated, B cell mediated or otherwise, is one of the variables included in human tolerance to a polypeptide. The constant region of the bispecific antibody is preferably a human constant region. The constant region may contain one or more, preferably no more than 10, preferably no more than 5 amino acid differences from the constant region of a naturally occurring human antibody. Preferably, the constant portion is completely derived from naturally occurring human antibodies. The various antibodies produced herein are derived from a human antibody variable domain library. Therefore, these variable domains are human. The unique CDR region may be derived from humans, synthetic or from another organism. When the variable region has an amino acid sequence identical to the amino acid sequence of the variable region of a naturally occurring human antibody (but excluding the CDR region), the variable region is considered to be a human variable region. In antibodies, the variable region of the VH binding to ERBB2, the VH binding to ERBB3 or the light chain may contain one or more, preferably no more than 10, preferably no more than 5 amino acid differences from the naturally occurring variable region of a human antibody, excluding possible differences in the amino acid sequence of the CDR region. Such mutations also occur in nature in the case of somatic hypermutation.

[0168] Antibodies can be derived from a variety of animal species, at least with respect to the heavy chain variable region. It is common practice to humanize such, for example, murine heavy chain variable regions. There are several ways to achieve this, one of which is to graft the CDRs into a human heavy chain variable region having a 3D structure that matches the 3D structure of the murine heavy chain variable region; deimmunization of the murine heavy chain variable region is preferably performed by removing known or suspected T-cell or B-cell epitopes from the murine heavy chain variable region. This removal is usually achieved by replacing one or more amino acids in the epitope with another (usually conservative) amino acid, so that the sequence of the epitope is modified so that it is no longer a T-cell epitope or a B-cell epitope.

[0169] Such deimmunized murine heavy chain variable regions have lower immunogenicity in humans than the original murine heavy chain variable regions. Preferably, the variable region or domain is further humanized, such as, for example, veneered. By using veneer technology, external residues that are easily encountered by the immune system are selectively replaced with human residues to provide a hybrid molecule comprising a veneered surface that is weakly immunogenic or substantially non-immunogenic. The animal used in the present invention is preferably a mammal, more preferably a primate, and most preferably a human.

[0170] Alternatively, the antibodies disclosed herein comprise the constant region of human antibodies. According to the differences in the heavy chain constant domains, antibodies are divided into five classes or isotypes: IgG, IgA, IgM, IgD and IgE. These classes or isotypes comprise at least one of the heavy chains named with corresponding Greek letters. Alternatively, the constant region comprises an IgG constant region, alternatively, an IgG1 constant region, alternatively, an IgG1 constant region comprising mutations. Some variations in the IgG1 constant region occur in nature, such as (for example) allotypes G1m1, 17 and G1m3, and / or are allowed without changing the immunological properties of the resulting antibodies. Usually about 1-10 amino acid insertions, deletions, substitutions or combinations thereof are allowed in the constant region.

[0171] Optionally, the antibodies of the present invention (including but not limited to bispecific antibodies) comprise an antigen binding site that can bind to the extracellular portion of ERBB3, which blocks ERBB3 and its ligand, heregulin. Optionally, the antibody also comprises an antigen binding site that can bind to the domain III of the extracellular portion of ERBB3. Optionally, the antibody also comprises an antigen binding site that can bind to the extracellular portion of ERBB2. Optionally, the antibody comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3. The bispecific antibody of the present invention comprises a first antigen binding site that binds to the extracellular portion of ERBB2 and a second antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the bispecific antibody has a first antigen binding site that binds to the domain I of ERBB2 and a second antigen binding site that binds to the domain III of ERBB3. Optionally, the affinity of the first antigen binding site to ERBB2 is lower than the affinity of the second antigen binding site to ERBB3. Optionally, the bispecific antibody is or comprises Zenocutuzumab (International Nonproprietary Name).

[0172] Optionally, the cancer is non-NRG1 fusion positive. Non-NRG1 fusion positive or non-NRG1 fusion negative means that any cancer or individual mentioned herein does not contain a NRG1 fusion gene, in particular, the individual or cancer does not contain a NRG fusion gene, which expresses a protein containing a NRG1 EGF-like domain. Optionally, the individual contains cancer-associated cells, such as cancer-associated fibroblasts, which are non-NRG1 fusion positive. The cancer-associated cells are usually located in the human prostate.

[0173] The bispecific antibody of the present invention comprises a first antigen binding site that binds to the extracellular portion of ERBB2 and a second antigen binding site that binds to the extracellular portion of ERBB3. Optionally, the bispecific antibody has a first antigen binding site that binds to domain I of ERBB2 and a second antigen binding site that binds to domain III of ERBB3. Optionally, the affinity of the first antigen binding site for ERBB2 is lower than the affinity of the second antigen binding site for ERBB3.

[0174] Optionally, the bispecific antibody comprises

[0175] i) at least a CDR1, CDR2 and CDR3 sequence in an ERBB2-specific heavy chain variable region selected from the group consisting of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or wherein the antibody comprises a CDR sequence that differs by at most 3 amino acids, preferably at most 2 amino acids, preferably at most 1 amino acid from the CDR1, CDR2, and CDR3 sequences of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or

[0176] ii) at least the CDR1, CDR2 and CDR3 sequences of an ERBB3-specific heavy chain variable region selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or a combination thereof The antibody comprises a CDR sequence that differs from the following CDR1, CDR2, and CDR3 sequences by at most 3 amino acids, preferably at most 2 amino acids, and preferably at most 1 amino acid: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0177] Optionally, the bispecific antibody comprises

[0178] i) an ERBB2-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the following heavy chain variable region sequence: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or

[0179] ii) an ERBB3-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the heavy chain variable region sequence of MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0180] Optionally, the bispecific antibody used in the present invention is MF3958x MF3178, which comprises the heavy chain variable regions MF3958 (anti-ERBB2) and MF3178 (anti-ERBB3). MF3958x MF3178 has been shown to be well tolerated as a single agent with a low risk of immunogenicity in the treatment of more than 100 patients, making it an excellent agent for combination therapy, with advantages over other anti-ERBB2 and / or anti-ERBB3 targeted agents. Without being bound by any theory, the efficacy of MF3958x MF3178 in treating cancer patients with ERBB2 and ERBB3 positive cells carrying ERBB3 mutations is believed to be based on the epitope specificity and affinity imbalance of MF3958x MF3178, which allows MF3958x MF3178 to dock to domain 1 of ERBB2 and prevent ERBB3 from forming dimers with ERBB2 at domain 3, thereby disrupting the activation of the PI3K pathway.

[0181] The bispecific antibody comprises a variable domain comprising the first antigen binding site and a variable domain comprising the second antigen binding site, preferably comprising a light chain variable region comprising a CDR1 having the sequence (RASQSISSYLN), a CDR2 having the sequence (AASSLQS), and a CDR3 having the sequence (QQSYSTPPT), wherein according to the KABAT numbering or according to the IMGT numbering system, each CDR is QSISSY, AAS and QQSYSTPPT, respectively.

[0182] The bispecific antibody comprises a variable domain comprising the first antigen-binding site and a variable domain comprising the second antigen-binding site, preferably comprising Figure 1 a or Figure 1 The sequences of the light chain variable region and / or CDR1, CDR2 and CDR3 shown in b are QSISSY, AAS and QQSYSTPPT, respectively, according to the IMGT numbering system ( Figure 1 f).

[0183] The amount of bispecific antibody to be administered to an individual is generally within the therapeutic window, meaning that a sufficient amount is used to obtain a therapeutic effect while the amount does not exceed a threshold that results in an unacceptable degree of side effects. The dose level selected will depend on a variety of factors, including the route of administration, the time of administration, the rate of excretion of the specific compound used, the duration of treatment, other drugs, compounds and / or materials used in combination, the age, sex, weight, condition, general health and medical history of the individual being treated, and similar factors well known in the medical field. The dose range is 200-1000 mg, once a week, every two weeks or every three weeks. Preferably, the administration of the therapeutic agent of the present invention targeting ERBB2xERBB3 follows a dosing regimen of 750 mg per week, every two weeks or every three weeks, preferably a dose of 750 mg every two weeks or every three weeks. Preferably, it is administered to a cancer individual with a solid tumor carrying an ERBB3 mutation, after which the dosing regimen includes a fixed dose of 400 mg per week, preferably starting after a single administration of 800 mg. After this alternative dosing regimen, the bispecific antibody of the present invention is preferably administered at a dose of 400 mg per week for 3 weeks, followed by no administration for 1 week. This is followed by one or more four-week cycles consisting of a fixed dose of 400 mg once every three weeks, followed by no administration for one week. This regimen is preferably performed until a therapeutic effect is observed. The dosing regimen of the present invention comprises a biweekly cycle, wherein after an initial administration of 750 mg for a four-hour infusion, a fixed dose of 750 mg is started once a week, followed by a two-hour infusion of 750 mg once every two weeks, for a period of 4 weeks. This regimen is preferably performed until a therapeutic effect is observed.

[0184] Administration preferably involves two intravenous infusions of the bispecific antibody of the invention to achieve the full dose, preferably >360 mg of the antibody. Alternatively, the full dose may be administered as a single infusion at a lower dose, for example when the antibody dose is ≤360 mg. Premedication may be included in the dosing regimen to mitigate infusion-related reactions.

[0185] Preferably, treatment includes stabilizing the tumor in terms of size or lesions or preventing further growth of the tumor, including shrinking the tumor. Preferably, treatment or administration is performed using the bispecific antibody of the present invention with a weekly regimen, and continues for at least 1, 2, 4, 8 or at least 12 months. Preferably, the subsequent dosing regimen includes a weekly cycle of a fixed dose of 400 mg per week after the initial administration of 800 mg. Starting from the 3rd week, the bispecific antibody of the present invention is administered at a dose of 400 mg per week for 3 weeks, and then the bispecific antibody of the present invention is not administered for 1 week. Alternatively, the subsequent dosing regimen includes a two-week cycle, wherein after the initial administration of 750 mg for four hours, a fixed dose of 750 mg per week is started, and then a 2-hour infusion of 750 mg is performed once every two weeks, and the cycle is 4 weeks. Another alternative includes a fixed dose of 750 mg administered to each individual every three weeks.

[0186] Preferably, the bispecific antibody has a first antigen binding site that binds or can bind to the extracellular part of ERBB2 and a second antigen binding site that binds or can bind to the extracellular part of ERBB3, in particular MF3958 x MF3178, stabilizes tumors of castration-resistant prostate cancer in size or lesions, or the treatment prevents further tumor growth of castration-resistant prostate cancer.

[0187] The antibodies of the present invention can be formulated as pharmaceutical compositions comprising a pharmaceutically acceptable carrier, diluent or excipient, and an additional, optional active agent. The antibodies and compositions comprising the antibodies can be administered by any route, including parenteral, enteral, and topical administration. Parenteral administration is typically by injection, and includes, for example, intravenous, intramuscular, intraarterial, intrathecal, intraventricular, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcutaneous, intraarticular, subcapsular, subarachnoid, intraspinal, intracerebrospinal, intratumoral, intrasternal injection, and infusion.

[0188] The present invention provides bispecific antibodies for use in the methods and treatments described herein. Suitable bispecific antibodies comprise a first antigen binding site that binds or can bind to ERBB2 and a second antigen binding site that binds or can bind to ERBB3. The bispecific antibody reduces or can reduce the ligand-induced receptor function of ERBB3 on ERBB2 and ERBB3-positive cells and / or disrupts ERBB2 and ERBB3 heterodimerization. Preferred antibodies and their preparation are disclosed in WO 2015 / 130173, which is incorporated herein by reference. The examples in WO 2015 / 130173 further describe many properties of antibodies, such as ligand binding and epitope mapping positioning.

[0189] Alternatively, the present invention provides antibodies that bind or can bind to ERBB3. Optionally, the antibody binds to domain III of ERBB3 and comprises CDR1, CDR2 and CDR3 sequences as disclosed herein. Optionally, the antibody is a monospecific antibody, such as patritumab (U3-1287 / A888), seribantumab (MM-121), lumretuzumab (RG7116, RO-5479599), elgemtumab (LJM716), AV-203, KTN3379 (CDX-3379), or GSK2849330. Optionally, the antibody is an antibody-drug conjugate, such as patritumab-deruxtecan (patritumab deruxtecan) (U3-1402). Optionally, the antibody is a monospecific bivalent antibody.

[0190] Alternatively, patritumab is administered at 18 mg / kg once every 21 days followed by 9 mg / kg once every 21 days.

[0191] Alternatively, seribantumab is administered at a 40 mg / kg loading dose, followed by a weekly 20 mg / kg maintenance dose (40 / 20 mg / kg). The dosage or schedule may be adjusted at the discretion of the treating physician. Alternatively, seribantumab is administered at a weekly dose of 3 g, administered via intravenous injection (IV).

[0192] Alternatively, lumretuzumab is administered at 500 or 1000 mg every 3 weeks via IV infusion in combination with Pertuzumab, wherein Pertuzumab is administered at an initial loading dose of 840 mg every 3 weeks via IV infusion, followed by a maintenance dose of 420 mg once every 3 weeks via IV infusion.

[0193] Alternatively, patritumab deruxtecan is administered at 5.6 mg / kg intravenously every 3 weeks (q3W).

[0194] Alternatively, KTN3379 / CDX-3379 is administered as 20 mg / kg intravenously every 3 weeks (q3W). Alternatively, CDX-3379 is administered in combination with cetuximab at a dose of 12 mg / kg once every three weeks, with 400 mg / m on the first day. 2 Cetuximab, then weekly at a dose of 250 mg / m 2 Cetuximab.

[0195] Alternatively, AV-203 is administered intravenously at 20 mg / kg every 2 weeks (q2W).

[0196] Alternatively, GSK2849330 is administered once a week at a dose of 30 mg / kg.

[0197] Optionally, the bispecific antibody disclosed herein comprises:

[0198] - at least the CDR3 sequence, preferably at least the CDR1, CDR2 and CDR3 sequence, in the ERBB2-specific heavy chain variable region is selected from the group consisting of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or the heavy chain variable region sequence differs from the referenced heavy chain variable region sequence by at most 15 amino acids, preferably by at most 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acids, more preferably by at most 1, 2, 3, 4 or 5 amino acids; and / or

[0199] - at least the CDR3 sequence, preferably at least the CDR1, CDR2 and CDR3 sequence, in the ERBB3-specific heavy chain variable region is selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or the heavy chain variable region sequence differs from the cited heavy chain variable region sequence by at most 15 amino acids, preferably by at most 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acids, more preferably by at most 1, 2, 3, 4 or 5 amino acids.

[0200] Alternatively, as disclosed herein, antibodies that bind to ERBB3 but not necessarily ERBB2 comprise:

[0201] - at least the CDR3 sequence, preferably at least the CDR1, CDR2 and CDR3 sequence, in the ERBB3-specific heavy chain variable region is selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or the heavy chain variable region sequence differs from the cited heavy chain variable region sequence by at most 15 amino acids, preferably by at most 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acids, more preferably by at most 1, 2, 3, 4 or 5 amino acids.

[0202] The CDR sequences may be altered, for example, for optimization purposes, preferably to improve the binding efficacy or stability of the antibody. The optimization is performed, for example, by a mutation induction process, after which the resulting antibodies are preferably tested for stability and / or binding affinity, and CDR sequences with enhanced ERBB2 or ERBB3-specificity are preferably selected. The skilled person is able to generate antibody variants comprising at least one altered CDR sequence. For example, conservative amino acid substitutions are applied. Some examples of conservative amino acid substitutions include substitution of one hydrophobic residue such as isoleucine, valine, leucine or methionine for another hydrophobic residue, and substitution of one polar residue for another polar residue, such as substitution of arginine for lysine, substitution of glutamic acid for aspartic acid, or substitution of asparagine for glutamine.

[0203] Optionally, the antibody comprises a variable domain that binds to ERBB2, wherein the VH chain of the variable domain comprises the amino acid sequence of VH chain MF2973; MF3004; MF3958 (which is a humanized MF2971); MF2971; MF3025; MF2916; MF3991 (which is a humanized MF3004); MF3031 or MF3003; or comprises VH chain MF2973; MF3004 MF3958 (which is a humanized MF2971); MF2971; MF3025; MF2916; MF3991 (which is a humanized MF3004); the amino acid sequence of MF3031 or MF3003, with a maximum of 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably a maximum of 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof, relative to the above VH chain sequence. The VH chain of the variable domain that binds to ERBB2 preferably comprises the following amino acid sequence:

[0204] - MF2971 or a humanized version thereof, wherein the humanized version preferably comprises the amino acid sequence of MF3958; or

[0205] -MF3004 or a humanized version thereof, wherein the humanized version preferably comprises the amino acid sequence of MF3991. In one embodiment, the VH chain of the variable domain that binds to ERBB2 comprises the amino acid sequence of the VH chain MF2971 or a humanized version thereof, wherein the humanized version preferably comprises the amino acid sequence of MF3958; or MF3004 or a humanized version thereof, wherein the humanized version preferably comprises the amino acid sequence of MF3991, wherein the referenced VH sequence has a maximum of 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably a maximum of 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof relative to the respective sequence. In a preferred embodiment, the VH chain of the variable domain that binds to ERBB2 comprises the amino acid sequence of MF3958; or comprises the amino acid sequence of MF3958 having up to 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably up to 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or a combination thereof relative to the VH chain sequence.

[0206] The VH chain that binds to the ERBB3 variable domain preferably comprises the amino acid sequence of the VH chain MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074; or comprises the VH chain MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF The amino acid sequence of MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074, which has a maximum of 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably a maximum of 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or a combination thereof relative to the VH chain sequence. The VH chain that binds to the ERBB3 variable domain preferably comprises the amino acid sequence of MF3178, MF3176, MF3163, MF6058, MF6061 or MF6065; or comprises the amino acid sequence of MF3178, MF3176, MF3163, MF6058, MF6061 or MF6065 having up to 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably up to 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or a combination thereof, relative to the respective VH chain sequence. In a preferred embodiment, the VH chain that binds to the ERBB3 variable domain comprises the MF3178 amino acid sequence; or comprises the amino acid sequence of MF3178, which has up to 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably up to 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof relative to the VH chain sequence. Preferably, the above amino acid insertions, deletions and substitutions are not present in the CDR3 region. The above amino acid insertions, deletions and substitutions are also preferably not present in the CDR1 and CDR2 regions. The above amino acid insertions, deletions and substitutions are also preferably not present in the FR4 region.

[0207] Optionally, the antibody comprises at least the CDR1, CDR2 and CDR3 sequences of MF2971, MF3958, MF3004 or MF3991, and preferably comprises at least the CDR1, CDR2 and CDR3 sequences of MF3958. The antibody preferably comprises at least the CDR1, CDR2 and CDR3 sequences of MF3178, MF3176, MF3163, MF6058, MF6061 or MF6065, and preferably comprises at least the CDR1, CDR2 and CDR3 sequences of MF3178.

[0208] Optionally, the ERBB2-specific heavy chain variable region comprises the amino acid sequence of VH chain MF3958, which has up to 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably up to 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof, relative to the VH chain sequence (preferably wherein the insertions, deletions, substitutions are not in CDR1, CDR2 or CDR3). Optionally, they are also not present in the FR4 region. Optionally, the amino acid substitutions are conservative amino acid substitutions.

[0209] Optionally, the amino acid sequence of the ERBB3-specific heavy chain variable region VH chain MF3178 has a maximum of 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably a maximum of 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof relative to the VH chain sequence. The one or more amino acid insertions, deletions, substitutions or combinations thereof are preferably not in the CDR1, CDR2 or CDR3 regions of the VH chain. They are preferably also not present in the FR4 region. The amino acid substitutions are preferably conservative amino acid substitutions.

[0210] Optionally, the ERBB2-specific heavy chain variable region comprises the amino acid sequence of VH chain MF3991, which has up to 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably up to 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof, relative to the VH chain sequence (preferably wherein the insertions, deletions, substitutions are not in CDR1, CDR2 or CDR3). Optionally, they are also not present in the FR4 region. Optionally, the amino acid substitutions are conservative amino acid substitutions.

[0211] Optionally, the amino acid sequence of the ERBB3-specific heavy chain variable region VH chain MF3178 has a maximum of 15, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, more preferably a maximum of 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof relative to the VH chain sequence. The one or more amino acid insertions, deletions, substitutions or combinations thereof are preferably not in the CDR1, CDR2 or CDR3 regions of the VH chain. They are preferably also not present in the FR4 region. The amino acid substitutions are preferably conservative amino acid substitutions.

[0212] Optionally, the first antigen-binding site of the antibody comprises at least the CDR1, CDR2 and CDR3 sequences of MF3958, or CDR1, CDR2 and CDR3 sequences that differ from the CDR1, CDR2 and CDR3 sequences of MF3958 in at most 3, preferably at most 2, and optimally at most 1 amino acid, and wherein the second antigen-binding site comprises at least the CDR1, CDR2 and CDR3 sequences of MF3178, or CDR1, CDR2 and CDR3 sequences that differ from the CDR1, CDR2 and CDR3 sequences of MF3178 in at most 3, preferably at most 2, and optimally at most 1 amino acid.

[0213] Optionally, the bispecific antibody comprises i) a first antigen binding site comprising an ERBB2-specific heavy chain variable region and a light chain variable region, wherein the ERBB2-specific heavy chain variable region comprises the CDR1, CDR2 and CDR3 sequences of MF3958, and ii) a second antigen binding site comprising an ERBB3-specific heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the CDR1, CDR2 and CDR3 sequences of MF3178.

[0214] Optionally, the ERBB2-specific heavy chain variable region has the MF3958 sequence and the ERBB3-specific heavy chain variable region has the MF3178 sequence. This combination is also referred to as the PB4188 antibody. Preferably, the PB4188 antibody is afucosylated.

[0215] Optionally, the bispecific antibody comprises Figure 3 The "heavy chain binding to ERBB2" shown in a and Figure 3 The "heavy chain binding to ERBB3" shown in b.

[0216] Optionally, the antigen binding site of the bispecific antibody comprises a common light chain as defined herein, preferably a germline common light chain, preferably a rearranged germline human κ light chain IgVκ1-39*01 / IGJκ1*01 or a fragment or functional derivative thereof (according to the nomenclature of the IMGT database global webpage imgt.org). The terms rearranged germline human κ light chain IgVκ1-39*01 / IGJκ1*01, IGKV1-39 / IGKJ1, huVκ1-39 light chain or simply Vκ1-39 are used. The light chain may have 1, 2, 3, 4 or 5 amino acid insertions, deletions, substitutions or combinations thereof. The 1, 2, 3, 4 or 5 amino acid substitutions are preferably conservative amino acid substitutions, insertions, deletions, substitutions or combinations thereof, preferably not in the CDR3 region of the VL chain, preferably not in the CDR1, CDR2 or CDR3 region or FR4 region of the VL chain. Preferably, the first antigen binding site and the second antigen binding site comprise the same light chain variable region, or a common light chain. Preferably, the light chain variable region comprises a CDR1 having the sequence (RASQSISSYLN), a CDR2 having the sequence (AASSLQS) and a CDR3 having the sequence (QQSYSTPPT), wherein according to the KABAT numbering or according to the IMGT numbering system, the CDRs are QSISSY, AAS and QQSYSTPPT, respectively. Preferably, the light chain variable region comprises Figure 1 The consensus light chain sequence is shown.

[0217] A variety of methods can be used to produce bispecific antibodies and are discussed in WO 2015 / 130173. One method involves expressing two different heavy chains and two different light chains in a cell and collecting the antibodies produced by the cell. Antibodies produced in this manner will generally contain a collection of antibodies with different combinations of heavy and light chains, some of which are desired bispecific antibodies. The bispecific antibodies can then be purified from the collection.

[0218] The ratio of bispecific antibodies produced by cells to other antibodies can be increased in a variety of ways. Preferably, the ratio is increased by expressing two substantially identical light chains instead of two different light chains in the cell. This concept is also referred to in the art as the "common light chain" method. Compared to expressing two different light chains, when substantially identical light chains act together with two different heavy chains to allow the formation of variable domains with different antigen binding sites and accompanying different binding properties, the ratio of bispecific antibodies produced by cells is significantly increased compared to other antibodies. Compared to the pairing of two identical heavy chains, the ratio of bispecific antibodies produced by cells can be further increased by stimulating the pairing of two different heavy chains with each other. Various methods for achieving such heavy chain heterodimerization are described in the art. A preferred method is described in PCT application number PCT / NL2013 / 050294 (WO 2013 / 157954A1), which is incorporated herein by reference. Methods and means for producing bispecific antibodies by a single cell are disclosed, thereby providing means for the formation of bispecific antibodies that are more inclined to the formation of monospecific antibodies.

[0219] For the purpose of clear and concise description, the features are described herein as part of the same or separate embodiments, however, it should be understood that the scope of the present invention may include embodiments with all or some of the described feature combinations. In addition, any aspect disclosed herein related to any use in the treatment method according to the present invention is also applicable to the treatment method of the present invention, and vice versa.

[0220] Items

[0221] 2. A bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3, for use in a method of treating castration-resistant prostate cancer in an individual.

[0222] 3. The bispecific antibody for use according to item 1, wherein the cancer has progressed after previous treatment with an androgen receptor axis-targeting agent.

[0223] 4. The bispecific antibody for use as described in item 2, wherein the androgen receptor axis-targeting agent is an androgen receptor antagonist, such as a second-generation androgen receptor antagonist.

[0224] 5. The bispecific antibody for use according to item 3, wherein the androgen receptor antagonist is enzalutamide.

[0225] 6. The bispecific antibody for use as described in item 2, wherein the androgen receptor axis-targeting agent is an androgen synthesis inhibitor, such as abiraterone acetate.

[0226] 7. The bispecific antibody for use according to any of the preceding clauses, wherein the method of treatment further comprises the use of an androgen receptor axis-targeting agent.

[0227] 8. The bispecific antibody for use according to any one of items 1 to 5, wherein the method of treatment further comprises the use of an androgen receptor antagonist, such as a second generation androgen receptor antagonist, such as enzalutamide.

[0228] 9. The bispecific antibody for use according to any one of items 1 to 5, wherein the method of treatment further comprises the use of an androgen synthesis inhibitor, such as abiraterone acetate.

[0229] 10. The bispecific antibody for use of any one of items 1 to 4 or 6 to 7, wherein if the cancer has worsened after previous treatment with an androgen receptor antagonist, the method of treatment using the bispecific antibody further comprises the use of an androgen receptor antagonist.

[0230] 11. The bispecific antibody for use according to item 9, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody are the same.

[0231] 12. The bispecific antibody for use or the method as described in item 9 or 10, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment with the bispecific antibody are both enzalutamide.

[0232] 13. The bispecific antibody for use of any one of items 4, 7 or 11, wherein enzalutamide is administered once daily at 160 mg.

[0233] 14. The bispecific antibody for use or method of any one of items 1, 2, 5, 6 or 8, wherein if the cancer has progressed after previous treatment with an androgen synthesis inhibitor, the method of treatment using the bispecific antibody further comprises the use of an androgen synthesis inhibitor.

[0234] 15. The bispecific antibody for use according to item 13, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment with the bispecific antibody are the same.

[0235] 16. The bispecific antibody for use according to item 13 or 14, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the treatment method with the bispecific antibody are both abiraterone acetate.

[0236] 17. The bispecific antibody for use according to any one of items 5, 8 or 15, wherein abiraterone acetate is administered once daily at 1000 mg.

[0237] 18. The bispecific antibody for use according to item 16, wherein abiraterone acetate and prednisone are administered in combination at 5 mg twice daily.

[0238] 19. A method of treating an individual having castration-resistant prostate cancer, the method comprising administering to the individual a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3.

[0239] 20. Use of a bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3 in the manufacture of a medicament for treating castration-resistant prostate cancer in an individual.

[0240] 21. The method of treatment or use of clause 18 or 19, wherein the cancer has progressed after previous treatment with an androgen receptor axis-targeting agent.

[0241] 22. The method or use of item 20, wherein the androgen receptor axis-targeting agent is an androgen receptor antagonist, such as a second generation androgen receptor antagonist.

[0242] 23. The method or use according to item 21, wherein the androgen receptor antagonist is enzalutamide.

[0243] 24. The method or use of clause 20, wherein the androgen receptor axis-targeting agent is an androgen synthesis inhibitor, such as abiraterone acetate.

[0244] 25. The method or use of any one of items 18 to 23, wherein the use of the bispecific antibody for treatment or for the manufacture of a medicament further comprises administering or using an androgen receptor axis-targeting agent.

[0245] 26. The method of treatment or use of any one of items 18 to 23, wherein the use of the bispecific antibody for treatment or for the manufacture of a medicament further comprises administering or using an androgen receptor antagonist, such as a second generation androgen receptor antagonist, such as enzalutamide.

[0246] 27. The method or use of any one of items 18 to 23, wherein the treatment with the bispecific antibody or the use for the manufacture of a medicament further comprises administering or using an androgen synthesis inhibitor, such as abiraterone acetate.

[0247] 28. The method of treatment or use of any one of items 18 to 26, wherein if the cancer has worsened after previous treatment with an androgen receptor antagonist, then the method of treatment using the bispecific antibody or the use for the manufacture of a medicament further comprises administering or using an androgen receptor antagonist.

[0248] 29. The method of treatment or use according to item 27, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody or the use for the manufacture of a medicament are the same.

[0249] 30. The method of treatment or use according to item 27 or 28, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody or the use for the manufacture of a medicament are both enzalutamide.

[0250] 31. The method or use of any one of clauses 22, 25 or 29, wherein enzalutamide is administered once daily at 160 mg.

[0251] 32. The method of treatment or use of any one of items 18, 19, 23, 24 or 26, wherein if the cancer has worsened following previous treatment with an androgen synthesis inhibitor, the method of treatment using the bispecific antibody or the use for the manufacture of a medicament further comprises administering or using an androgen synthesis inhibitor.

[0252] 33. The method of treatment or use according to item 31, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody or the use for the manufacture of a medicament are the same.

[0253] 34. The method of treatment or use according to item 31 or 32, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody or the use for the manufacture of a medicament are both abiraterone acetate.

[0254] 35. The method or use of any one of clauses 23, 26 or 33, wherein abiraterone acetate is administered once daily at 1000 mg.

[0255] 36. The method or use of claim 34, wherein abiraterone acetate is / will be administered in combination with prednisone at 5 mg twice daily.

[0256] 37. The bispecific antibody for use according to any one of items 1 to 17, or the method of treatment or use according to any one of items 18 to 35, wherein the method of treatment comprises administering the bispecific antibody in an amount of 750 mg once every two weeks.

[0257] 38. The bispecific antibody for use of any one of items 1 to 17 or 36, or the method of treatment or use of any one of items 18 to 36, wherein the individual or cancer has PTEN wild-type status.

[0258] 39. The bispecific antibody for use of any one of items 1 to 17 or 36, or the method of treatment or use of any one of items 18 to 36, wherein the individual or cancer does not exhibit PTEN loss.

[0259] 40. The bispecific antibody for use of any one of items 1 to 17 or items 36 to 38, or the method of treatment or use of any one of items 18 to 38, wherein the method of treatment comprises administering to an individual in need thereof a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3.

[0260] 41. The bispecific antibody for use of any one of items 6 to 17 or items 36 to 39, or the method of treatment or use of any one of items 24 to 39, wherein the androgen receptor axis-targeting agent is administered or is to be administered according to a medical prescription indication established by a health authority such as the FDA.

[0261] 42. The bispecific antibody for use of any one of items 1 to 17 or 36 to 40, or the method of treatment or use of any one of items 18 to 40, wherein the cancer is characterized as histologically confirmed prostate adenocarcinoma, optionally without neuroendocrine differentiation or small cell characteristics.

[0262] 43. The bispecific antibody for use of any one of items 1 to 17 or items 36 to 41, or the method of treatment or use of any one of items 18 to 41, wherein the bispecific antibody comprises a first antigen binding site that binds to domain I of ERBB2, and a second antigen binding site that binds to domain III of ERBB3.

[0263] 44. The bispecific antibody for use according to any one of items 1 to 17 or 36 to 42, or the method of treatment or use according to any one of items 18 to 42, wherein the bispecific antibody comprises

[0264] i) at least a CDR1, CDR2 and CDR3 sequence in an ERBB2-specific heavy chain variable region selected from the group consisting of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or wherein the antibody comprises a CDR sequence that differs by at most 3 amino acids, preferably at most 2 amino acids, preferably at most 1 amino acid from the CDR1, CDR2, and CDR3 sequences of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or

[0265] ii) at least the CDR1, CDR2 and CDR3 sequences of an ERBB3-specific heavy chain variable region selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or a combination thereof The antibody comprises a CDR sequence that differs from the following CDR1, CDR2, and CDR3 sequences by at most 3 amino acids, preferably at most 2 amino acids, and preferably at most 1 amino acid: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0266] 45. The bispecific antibody for use according to any one of items 1 to 17 or 36 to 43, or the method of treatment or use according to any one of items 18 to 43, wherein the bispecific antibody comprises

[0267] i) an ERBB2-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the following heavy chain variable region sequence: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or

[0268] ii) an ERBB3-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the heavy chain variable region sequence of MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0269] 46. ​​The bispecific antibody for use of any one of items 1 to 17 or 36 to 44, or the method of treatment or use of any one of items 18 to 44, wherein the bispecific antibody comprises the heavy chain variable regions of MF3958 and MF3178.

[0270] 47. The bispecific antibody for use of any one of items 1 to 17 or 36 to 45, or the method of treatment or use of any one of items 18 to 45, wherein the bispecific antibody comprises a variable domain comprising the first antigen binding site and a variable domain comprising the second antigen binding site, and wherein the first and second antigen binding sites comprise a light chain variable region comprising a CDR1 comprising the sequence QSISSY, a CDR2 comprising the sequence AAS, and a CDR3 comprising the sequence QQSYSTPPT.

[0271] 48. An antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3 for use in a method of treating castration-resistant prostate cancer in an individual.

[0272] 49. A method of treating an individual having castration-resistant prostate cancer, the method comprising administering to the individual a therapeutically effective amount of an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3.

[0273] 50. Use of an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3 in the manufacture of a medicament for treating castration-resistant prostate cancer in an individual.

[0274] 51. The antibody for use of item 47, the method of treatment of item 48, or the use of item 49, wherein the antibody comprises an antigen binding site that binds domain III of ERBB3.

[0275] 52. The antibody for use according to item 47 or 50, the method of treatment according to item 48 or 50, or the use according to item 49 or 50, wherein the antibody comprises

[0276] i) at least the CDR1, CDR2 and CDR3 sequences in an ERBB3-specific heavy chain variable region selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or wherein The antibody comprises a CDR sequence that differs from the following CDR1, CDR2, and CDR3 sequences by at most 3 amino acids, preferably at most 2 amino acids, and preferably at most 1 amino acid: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0277] 53. The antibody for use of any one of items 47 or 50 to 51, the method of treatment of any one of items 48 or 50 to 51, or the use of any one of items 49 to 51, wherein the antibody comprises

[0278] i) an ERBB3-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the heavy chain variable region sequence of MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

[0279] 54. The antibody for use of any one of item 47 or items 50 to 52, the method of treatment of any one of item 48 or items 50 to 52, or the use of any one of items 49 to 52, wherein the antibody comprises the heavy chain variable region of MF3178.

[0280] 55. The antibody for use of any one of item 47 or items 50 to 53, the method of treatment of any one of item 48 or items 50 to 53, or the use of any one of items 49 to 53, wherein the antibody comprises a variable domain comprising an antigen binding site capable of binding to the extracellular portion of ERBB3, and wherein the antigen binding site comprises a light chain variable region comprising a CDR1 comprising the sequence QSISSY, a CDR2 comprising the sequence AAS, and a CDR3 comprising the sequence QQSYSTPPT.

[0281] 56. The antibody for use of any one of item 47 or items 50 to 54, the method of treatment of any one of item 48 or items 50 to 54, or the use of any one of items 49 to 54, wherein the antibody is a monospecific antibody that binds ERBB3, such as a monospecific bivalent antibody.

[0282] 57. The antibody for use of any one of clauses 47 or 50 to 55, the method of treatment of any one of clauses 48 or 50 to 55, or the use of any one of clauses 49 to 55, wherein the antibody comprises patritumab (U3-–1287 / A888), seribantumab (MM-121), lumretuzumab (RG7116, RO-5479599), elgemtumab (LJM716), AV-203, KTN3379 / CDX-3379, GSK2849330, or an antibody-drug conjugate such as patritumab deruxtecan (U3-1402).

[0283] 58. The antibody for use of any one of item 47 or items 50 to 55, the method of treatment of any one of item 48 or items 50 to 55, or the use of any one of items 49 to 55, wherein the antibody can reduce or decrease the ligand-induced receptor function of ERBB3.

[0284] 59. The antibody for use of any one of item 47 or items 50 to 55, the method of treatment of any one of item 48 or items 50 to 55, or the use of any one of items 49 to 55, wherein the antibody comprises an antigen binding site that binds to the extracellular portion of ERBB3, which blocks ERBB3 and its ligand heregulin.

[0285] 60. The antibody for use of any one of clauses 47 or 50 to 58, the method of treatment of any one of clauses 48 or 50 to 58, or the use of any one of clauses 49 to 58, wherein the cancer has worsened following prior treatment with an androgen receptor axis-targeting agent.

[0286] 61. The antibody for use, the method of treatment, or the use of clause 59, wherein the androgen receptor axis-targeting agent is an androgen receptor antagonist, such as a second generation androgen receptor antagonist.

[0287] 62. The antibody for use, the method of treatment, or the use of clause 60, wherein the androgen receptor antagonist is enzalutamide.

[0288] 63. The antibody for use, the method of treatment, or the use of clause 59, wherein the androgen receptor axis-targeting agent is an androgen synthesis inhibitor, such as abiraterone acetate.

[0289] 64. The antibody for use of any one of clauses 47 or 50 to 62, the method of treatment of any one of clauses 48 or 50 to 62, or the use of any one of clauses 49 to 62, wherein the method of treatment further comprises the use of an androgen receptor axis-targeting agent.

[0290] 65. The antibody for use of any one of clauses 47 or 50 to 62, the method of treatment of any one of clauses 48 or 50 to 62, or the use of any one of clauses 49 to 62, wherein the method of treatment further comprises the use of an androgen receptor antagonist, such as a second generation androgen receptor antagonist, such as enzalutamide.

[0291] 66. The antibody for use of any one of clauses 47 or 50 to 62, the method of treatment of any one of clauses 48 or 50 to 62, or the use of any one of clauses 49 to 62, wherein the method of treatment further comprises the use of an androgen synthesis inhibitor, such as abiraterone acetate.

[0292] 67. The antibody for use of any one of clauses 47, 50 to 61, or 63 to 64, the method of treatment of any one of clauses 48, 50 to 61, or 63 to 64, or the use of any one of clauses 49 to 61, or 63 to 64, wherein if the cancer has worsened following prior treatment with an androgen receptor antagonist, the method of treatment using the bispecific antibody further comprises the use of an androgen receptor antagonist.

[0293] 68. The antibody for use, the method of treatment, or the use of clause 66, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody are the same.

[0294] 69. The antibody for use, the method of treatment, or the use of clause 66 or 67, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody are both enzalutamide.

[0295] 70. The antibody for use of any one of items 61, 64, or 68, the method of treatment of any one of items 61, 64, or 68, or the use of any one of items 61, 64, or 68, wherein enzalutamide is administered once daily at 160 mg.

[0296] 71. The antibody for use of any one of item 47 or items 50 to 59, 62, 63 or 65, the method of treatment of any one of item 48 or items 50 to 59, 62, 63 or 65, or the use of any one of item 49 to 59, 62, 63 or 65, wherein if the cancer has worsened after previous treatment with an androgen synthesis inhibitor, the method of treatment using the bispecific antibody further comprises the use of an androgen synthesis inhibitor.

[0297] 72. The antibody for use according to item 70, the method of treatment according to item 70, or the use according to item 70, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody are the same.

[0298] 73. The antibody for use according to item 70 or 71, the method of treatment according to item 70 or 71, or the use according to item 70 or 71, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody are both abiraterone acetate.

[0299] 74. The antibody for use of any one of items 62, 65 or 72, the method of treatment of any one of items 62, 65 or 72, or the use of any one of items 62, 65 or 72, wherein abiraterone acetate is administered once daily at 1000 mg.

[0300] 75. The antibody for use according to item 73, the method of treatment according to item 73, or the use according to item 73, wherein abiraterone acetate is administered in combination with prednisone at 5 mg twice daily.

[0301] 76. The antibody for use of any one of item 47 or items 50 to 74, the method of treatment of any one of item 48 or items 50 to 74, or the use of any one of items 49 to 74, wherein the method of treatment comprises administering the bispecific antibody in an amount of 750 mg once every two weeks.

[0302] 77. The antibody for use of any one of item 47 or items 50 to 75, the method of treatment of any one of item 48 or items 50 to 75, or the use of any one of items 49 to 75, wherein the individual or cancer has PTEN wild-type status.

[0303] 78. The antibody for use of any one of item 47 or items 50 to 76, the method of treatment of any one of item 48 or items 50 to 76, or the use of any one of items 49 to 76, wherein the individual or cancer does not exhibit PTEN loss.

[0304] 79. The antibody for use of any one of item 47 or items 50 to 77, the method of treatment of any one of item 48 or items 50 to 77, or the use of any one of items 49 to 77, wherein the method of treatment comprises administering a therapeutically effective amount of the antibody to an individual in need thereof.

[0305] 80. The antibody for use of any one of clauses 47 or 50 to 78, the method of treatment of any one of clauses 48 or 50 to 78, or the use of any one of clauses 49 to 78, wherein the androgen receptor axis-targeting agent is administered or is to be administered according to a medical prescription indication established by a health authority such as the FDA.

[0306] 81. The antibody for use of any one of clauses 47 or 50 to 79, the method of treatment of any one of clauses 48 or 50 to 79, or the use of any one of clauses 49 to 79, wherein the cancer is characterized as histologically confirmed prostate adenocarcinoma, optionally without neuroendocrine differentiation or small cell features.

[0307] 82. A method for screening an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, selecting the individual for said treatment.

[0308] 83. A method for establishing whether an individual with castration-resistant prostate cancer is likely to respond to treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or to treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) screening out samples that do not exhibit PTEN loss, thereby establishing that the individual from whom the sample is derived is likely to respond to the treatment.

[0309] 84. A method for classifying individuals with castration-resistant prostate cancer based on PTEN status before treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or before treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the PTEN status in a sample obtained from the individual; b) if the sample does not exhibit PTEN loss, classifying the individual from whom the sample is derived as eligible for said treatment.

[0310] 85. The method of any one of items 81 to 83, wherein PTEN status is determined using IHC.

[0311] 86. The method of any one of items 81 to 83, wherein PTEN status is determined using a liquid biospecimen.

[0312] 87. A kit of parts comprising a bispecific antibody and an androgen receptor axis-targeting agent, wherein the bispecific antibody comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3.

[0313] 88. The multi-component kit of claim 86, further comprising instructions for use.

[0314] 89. The multi-component kit of item 86 or 87, wherein the instructions for use include instructions for administering the bispecific antibody and the androgen receptor axis-targeting agent.

[0315] 90. The multi-component kit of any one of items 86 to 88, wherein the androgen receptor axis-targeting agent comprises an androgen receptor antagonist such as a second generation androgen receptor antagonist such as enzalutamide, or comprises an androgen synthesis inhibitor such as abiraterone acetate, and wherein the bispecific antibody comprises zenocutuzumab.

[0316] 91. The multi-component kit of claim 89, wherein the instructions for use include administering 1000 mg of abiraterone acetate once daily in combination with 5 mg of prednisone twice daily, and administering the bispecific antibody in an amount of 750 mg once every two weeks.

[0317] 92. The kit of parts as described in item 89, wherein the instructions for use include administering 160 mg of enzalutamide once a day and administering 750 mg of the bispecific antibody once every two weeks.

[0318] 93. The multi-component kit of item 90 or 91, wherein the instructions for use of the abiraterone acetate or enzalutamide include instructions for oral administration, and the administration of the bispecific antibody includes instructions for intravenous injection.

[0319] 94. A kit of parts comprising an antibody comprising an antigen binding site that binds to an extracellular portion of ERBB3 and an androgen receptor axis-targeting agent.

[0320] 95. The multi-component kit of claim 93, further comprising instructions for use.

[0321] 96. The kit of parts as described in item 93 or 94, wherein the instructions for use include instructions for administering the antibody and the androgen receptor axis-targeting agent.

[0322] 97. A multi-component kit as described in any one of items 93 to 95, wherein the androgen receptor axis-targeting agent comprises an androgen receptor antagonist such as a second-generation androgen receptor antagonist such as enzalutamide, or comprises an androgen synthesis inhibitor such as abiraterone acetate, and wherein the antibody comprises zenocutuzumab.

[0323] 98. The multi-component kit of item 96, wherein the instructions for use include administering 1000 mg of abiraterone acetate once daily in combination with 5 mg of prednisone twice daily, and administering the antibody in an amount of 750 mg once every two weeks.

[0324] 99. The kit of parts as described in item 96, wherein the instructions for use include administering 160 mg of enzalutamide once a day and 750 mg of the antibody once every two weeks.

[0325] 100. The multi-component kit of item 97 or 98, wherein the instructions for use of the abiraterone acetate or enzalutamide include instructions for oral administration, and the administration of the antibody includes instructions for intravenous injection.

[0326] 101. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer has a PTEN deficiency state.

[0327] 102. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer exhibits PTEN deficiency.

[0328] 103. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer does not have an oncogenic driver mutation in any of the PI3K, AKT and / or mTOR pathways, or wherein the individual or cancer does not have upregulation of any of said pathways.

[0329] 104. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer does not exhibit an oncogenic driver mutation in any of the PI3K, AKT and / or mTOR pathways, or wherein the individual or cancer does not exhibit upregulation of any of said pathways.

[0330] 105. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer does not have an oncogenic driver mutation in any known tumor-associated gene or protein encoded thereby, such as EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1.

[0331] 106. The bispecific antibody for use of any one of items 1 to 17 or 36, the method of treatment or the use of any one of items 18 to 36, wherein the individual or cancer does not exhibit oncogenic driver mutations in any known tumor-associated gene or protein encoded thereby, such as EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1.

[0332] 107. The bispecific antibody for use of any one of item 47 or items 50 to 75, the method of treatment of any one of item 48 or items 50 to 75, or the use of any one of items 49 to 75, wherein the individual or cancer has a PTEN deficiency state.

[0333] 108. The bispecific antibody for use of any one of item 47 or items 50 to 75, the method of treatment of any one of item 48 or items 50 to 75, or the use of any one of items 49 to 75, wherein the individual or cancer exhibits PTEN loss.

[0334] 109. The bispecific antibody for use of any one of item 47 or items 50 to 75, the method of treatment of any one of item 48 or items 50 to 75, or the use of any one of items 49 to 75, wherein the individual or cancer does not have an oncogenic driver mutation in any known tumor-related gene or protein encoded thereby, such as EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET, and ROS1.

[0335] 110. The bispecific antibody for use of any one of item 47 or items 50 to 75, the method of treatment of any one of item 48 or items 50 to 75, or the use of any one of items 49 to 75, wherein the individual or cancer does not exhibit oncogenic driver mutations in any known tumor-associated gene or protein encoded thereby, such as EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET, and ROS1.

[0336] 111. A method for screening an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) determining the presence of oncogenic driver mutations in any of the PI3K, AKT and / or mTOR pathways, or the presence of mutations that regulate the PI3K, AKT and / or mTOR pathways in a sample obtained from the individual's cancer; and b) if the sample lacks oncogenic driver mutations in the PI3K, AKT and / or mTOR pathways, or lacks mutations that regulate the PI3K, AKT and / or mTOR pathways, then selecting the individual for said treatment.

[0337] 112. The method of item 110, wherein the individual's cancer is determined by next generation sequencing, such as DNA, RNA or whole transcriptome sequencing.

[0338] 113. A method for screening an individual with castration-resistant prostate cancer for treatment with a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3 or for treatment with an antibody comprising an antigen binding site that binds to the extracellular portion of ERBB3, the method comprising: a) determining the presence of an oncogenic driver mutation in any of the EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1 pathways in a sample obtained from the individual's cancer; b) selecting the individual for said treatment if the sample lacks said oncogenic driver mutation.

[0339] 114. The method of item 110, wherein the individual's cancer is determined by next generation sequencing, such as DNA, RNA or whole transcriptome sequencing.

[0340] 115. A method for screening an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) testing the individual's cancer by next-generation sequencing to determine whether an oncogenic driver mutation that regulates any of the PI3K, AKT and / or mTOR pathways is present in a sample obtained from the individual; b) if the sample lacks the oncogenic driver mutation, classifying the individual from which the sample was derived as eligible for the treatment.

[0341] 116. A method for screening an individual with castration-resistant prostate cancer for treatment with a bispecific antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB2 and an antigen binding site that can bind to the extracellular portion of ERBB3) or treatment with an antibody (which comprises an antigen binding site that can bind to the extracellular portion of ERBB3), the method comprising: a) testing the individual's cancer by determining by next-generation sequencing whether an oncogenic driver mutation, optionally any one of EGFR, cMET, ALK, BRAF, KRAS, NRAS, RET and ROS1, is present in a sample obtained from the individual; b) if the sample does not contain the oncogenic driver mutation, classifying the individual from whom the sample is derived as eligible for the treatment.

[0342] 117. The method of any one of items 110 to 115, wherein the individual or cancer further has PTEN wild-type status.

[0343] Examples

[0344] As used herein, "MFXXXX" (wherein X is independently a number from 0 to 9) refers to a Fab comprising a variable domain wherein VH has a Figure 3 Unless otherwise indicated, the light chain variable region of the variable domain generally has Figure 1 b. The light chain in the example has Figure 1c. "MFXXXX VH" refers to the amino acid sequence of the VH identified by a 4-digit number. The MF further comprises the constant region of the light chain, and the constant region of the heavy chain (which usually interacts with the constant region of the light chain). The VH / variable region of the heavy chain is different and is generally also a CH3 region, wherein one of the heavy chains has a KK mutation in its CH3 domain and the other has a complementary DE mutation in its CH3 domain (see references PCT / NL2013 / 050294 (published as WO2013 / 157954), and Figure 2 d and Figure 2 e). The bispecific antibody in the example has an Fc tail (which has a KK / DE CH3 heterodimerization domain), such as Figure 2 The indicated CH2 domain and CH1 domain, such as Figure 1 a Common light chain as indicated, and VH as indicated by MF numbers.

[0345] Example 1: Multispecific antibodies that bind to domain I of ERBB2 and domain III of ERBB3.

[0346] Bispecific antibodies comprising the heavy chain variable regions mentioned in Table 2 and Table 3 were obtained as described in WO2015 / 130173. The ERBB3 binding domains shown can also be used to provide monospecific antibodies.

[0347] ERBB2 binding domain ID SEQ ID NO ERBB3 binding domain ID SEQ ID NO MF2973 SEQ ID NO:2 MF3178 SEQ ID NO:47 MF3004 SEQ ID NO:7 MF3176 SEQ ID NO:52 MF3958 SEQ ID NO:12 MF3163 SEQ ID NO:57 MF2971 SEQ ID NO:17 MF6055 SEQ ID NO:62 MF3025 SEQ ID NO:22 MF6056 SEQ ID NO:67 MF2916 SEQ ID NO:27 MF6057 SEQ ID NO:72 MF3991 SEQ ID NO:32 MF6058 SEQ ID NO:77 MF3031 SEQ ID NO:37 MF6059 SEQ ID NO:82 MF3003 SEQ ID NO:42 MF6060 SEQ ID NO:87 MF6061 SEQ ID NO:92 MF6062 SEQ ID NO:97 MF6063 SEQ ID NO:102 MF6064 SEQ ID NO:107 MF6065 SEQ ID NO:112 MF6066 SEQ ID NO:117 MF6067 SEQ ID NO:122 MF6068 SEQ ID NO:127 MF6069 SEQ ID NO:132 MF6070 SEQ ID NO:137 MF6071 SEQ ID NO:142 MF6072 SEQ ID NO:147 MF6073 SEQ ID NO:152 MF6074 SEQ ID NO:157

[0348] Table 2: SEQ ID NOs of the heavy chain variable regions of bispecific antibodies binding to ERBB2 and ERBB3.

[0349] MF2973 MF3004 MF3958 MF2971 MF3025 MF2916 MF3991 MF3031 MF3003 MF3178 X X X X X X X X X MF3176 X X X X X X X X X MF3163 X X X X X X X X X MF6055 X X X X X X X X X MF6056 X X X X X X X X X MF6057 X X X X X X X X X MF6058 X X X X X X X X X MF6059 X X X X X X X X X MF6060 X X X X X X X X X MF6061 X X X X X X X X X MF6062 X X X X X X X X X MF6063 X X X X X X X X X MF6064 X X X X X X X X X MF6065 X X X X X X X X X MF6066 X X X X X X X X X MF6067 X X X X X X X X X MF6068 X X X X X X X X X MF6069 X X X X X X X X X MF6070 X X X X X X X X X MF6071 X X X X X X X X X MF6072 X X X X X X X X X MF6073 X X X X X X X X X MF6074 X X X X X X X X X

[0350] Table 3: In the bispecific antibodies of the invention, any heavy chain variable region that binds ERBB2 can be combined with any heavy chain variable region that binds ERBB3. Variants of the variable heavy chain regions can also be combined in the bispecific antibodies of the invention.

[0351] Example 2:

[0352] Clinical study with zenocutuzumab, a full-length IgG1 bispecific antibody comprising MF3958 x MF3178 targeting ERBB2 and ERBB3, in patients with castration-resistant prostate cancer.

[0353] This is a Phase II, open-label, multicenter, international study designed to evaluate the efficacy of zenocutuzumab in patients with metastatic mCRPC who have evidence of disease progression according to the Prostate Cancer Clinical Trials Working Group 3 (PCWG3) criteria, on the last line of prior hormonal therapy including the second-generation AR antagonist enzalutamide, or the androgen synthesis inhibitor abiraterone acetate. Patients will be included and will receive zenocutuzumab in combination with an AR-targeted agent who have experienced disease progression just prior to study entry. A subgroup of patients with phosphatase and tensin homolog (PTEN) wild-type status will be recruited. Safety assessment preparation will be performed on the first 4 to 6 patients.

[0354] Study Drug

[0355] Zenocutuzumab is an investigational medicinal product and its concomitant AR signaling inhibitor is considered a non-investigational medicinal product. Zenocutuzumab, a bispecific humanized full-length IgG1 antibody, is formulated at 20 mg / mL.

[0356] Zenocutuzumab

[0357] Zenoculumab will be administered as a 2-hour IV infusion on Day 1, then Q2W every 28-day cycle. A fixed dose of 750 mg will be administered.

[0358] Patients will receive zenoculumab in combination with other drugs. Premedication is required before each infusion of zenoculumab. The mandatory premedication regimen is:

[0359] Paracetamol / acetaminophen 1000 mg PO or IV.

[0360] Dexchlorpheniramine 5 mg IV (or other anti-H1 equivalent, PO or IV).

[0361] Dexamethasone 10 mg IV (or equivalent, PO or IV). Corticosteroids are mandatory only prior to dosing on Day 1 of Cycle 1 and should be used for subsequent injections at the discretion of the investigator to manage infusion-related reactions (IRRs).

[0362] The use of H2 antagonists is optional and may be given at the investigator's discretion.

[0363] Next-generation AR signaling inhibitors

[0364] Patients will receive zenocurizumab in combination with one of the following next-generation AR signaling inhibitors (which patients have received just prior to entering the study):

[0365] Abiraterone acetate 1000 mg PO QD in combination with prednisone 5 mg PO twice daily (BID).

[0366] Enzalutamide 160 mg PO QD.

[0367] Administration of enzalutamide or abiraterone acetate will begin on Day 1 of Cycle 1.

[0368] Abiraterone acetate: Abiraterone acetate is taken in combination with prednisone and should be taken on an empty stomach. Food should not be consumed for at least 2 hours before and at least 1 hour after each dose. The tablet should be swallowed whole with water. Abiraterone acetate is a 250-mg tablet that is white to off-white, oval in shape, and debossed on one side with AA250. The tablets should be stored at 20°C to 25°C (68°F-77°F); temperature fluctuations of 15°C to 30°C (59°F-86°F) are permitted.

[0369] Enzalutamide: Enzalutamide may be taken with or without food. Capsules should be swallowed whole. Enzalutamide is supplied as 40 mg white to off-white rectangular soft gelatin capsules printed with "MDV" in black ink. Capsules should be stored in a tightly closed container at 20°C to 25°C (68°F-77°F) in a dry place; temperature fluctuations of 15°C to 30°C (59°F-86°F) are permitted.

[0370] Treatment Indications

[0371] Next-generation AR signaling inhibitors will be administered according to the local prescribing information for each drug. Dose adjustments of enzalutamide or abiraterone acetate based on clinical judgment for drug-related toxicity are permitted:

[0372] Abiraterone acetate: For patients who develop hepatotoxicity during treatment (ALT and / or AST greater than 5×ULN or total bilirubin greater than 3×ULN), treatment should be interrupted. Once liver function tests return to the patient's baseline or ALT and AST values ​​≤2.5×ULN and total bilirubin less than ≤1.5×ULN, treatment can be restarted at a reduced dose of 750 mg QD. Once patients resume treatment, serum transaminases and bilirubin should be monitored at least every two weeks for 3 months and monthly thereafter. If hepatotoxicity recurs at the 750 mg QD dose, treatment can be restarted at a reduced dose of 500 mg QD once function tests return to the patient's baseline or ALT and AST ≤2.5×ULN and total bilirubin ≤1.5×ULN. If hepatotoxicity recurs after reducing the dose to 500 mg QD, treatment should be discontinued.

[0373] Enzalutamide: If a patient experiences ≥ Grade 3 toxicity or intolerable side effects, withhold dosing for 1 week or until symptoms improve to ≤ Grade 2, then resume at the same or reduced dose (120 or 80 mg), if warranted.

[0374] Treatment cessation

[0375] Zenoculumab will be administered until any of the following events occur, at which point it will be explicitly stopped unless helpfulness is perceived and agreed to by the sponsor. If there is a helpful event, whether to continue single-agent therapy will be discussed on a case-by-case basis and agreed to with the sponsor.

[0376] Worsening of the disease.

[0377] AE / unacceptable toxicity.

[0378] Withdraw your consent.

[0379] Patient non-cooperation.

[0380] Investigator's decision (e.g., clinical deterioration).

[0381] Treatment interruption > 6 consecutive weeks.

[0382] Discontinue any combination therapy.

[0383] Eligible patients will be enrolled and will receive consecutive treatment cycles, where treatment cycles are 4 weeks (28 days). All patients will receive a fixed dose of zenocurizumab 750mg IV Q2W.

[0384] Study Group

[0385] Inclusion criteria

[0386] Patients must meet all of the following requirements to enter the study:

[0387] 1. Sign the informed consent form before starting any research procedures.

[0388] 2. Aged ≥ 18 years when signing the informed consent form.

[0389] 3. The Eastern Cooperative Oncology Group (ECOG) daily physical status is 0 or 1.

[0390] 4. Expected life expectancy ≥ 12 weeks.

[0391] 5. At least 3 weeks have passed since any major surgery, completion of radiation therapy, completion of all previous systemic anticancer therapy, or at least 5 half-lives if the previous treatment was a single-agent small molecule therapeutic drug, and adequate recovery from any acute toxicity of the previous treatment to a National Cancer Institute (NCI)-Common Terminology Criteria for Adverse Events (CTCAE) v.5.0 grade ≤1, except for alopecia or neuropathy.

[0392] 6. Left ventricular ejection fraction (LVEF) ≥ 50% as detected by cardiac ultrasound (ECHO) or multi-channel ventricular function imaging (MUGA).

[0393] 7. Adequate Organ Function:

[0394] Absolute neutrophil count ≥ 1.5 × 10 9 / L.

[0395] Hemoglobin ≥ 9 g / dL.

[0396] ·Platelets ≥100×10 9 / L.

[0397] Serum calcium is within the normal range (or corrected with supplementation).

[0398] Alanine aminotransferase (ALT), aspartate aminotransferase (AST) ≤ 2.5 × upper limit of normal (ULN) (if the malignancy involves the liver, ALT / AST ≤ 5 × ULN is allowed).

[0399] Total bilirubin ≤1.5×ULN (if Gilbert's disease occurs, total bilirubin ≤3×ULN is allowed).

[0400] Glomerular filtration rate estimated by the Cockroft-Gault formula > 30 mL / min.

[0401] Serum albumin >3.0 g / dL.

[0402] 8. Representative tumor samples can be formalin-fixed paraffin-embedded (FFPE) tumor specimens from the beginning (i.e., obtained within 2 months before signing the informed consent form) or FFPE archived tumor specimens (preferably collected within 2 years after the start of the study treatment). Fresh FFPE samples are preferred.

[0403] 9. Sexually active male and female patients of childbearing age must agree to use one of the following highly effective birth control methods throughout the study and for 6 months after the last dose of Zenoculumab:

[0404] Combination (estrogen and progestin) hormonal contraceptives associated with ovulation inhibition: oral, vaginal, transdermal.

[0405] Progestin-only hormonal contraceptives associated with ovulation inhibition: oral, injectable, implantable, intrauterine device, intrauterine hormone-releasing system, bilateral tubal occlusion, partner vasectomy, sexual abstinence.

[0406] Further inclusion criteria: Patients had to meet all of the following requirements to enter the study:

[0407] B1. Histologically confirmed prostate adenocarcinoma without neuroendocrine differentiation or small cell features.

[0408] B2. Metastatic disease with at least 2 bone lesions documented on whole body bone scan or soft tissue disease documented on computed tomography (CT) scan / magnetic resonance imaging (MRI).

[0409] B3. Continuous androgen deprivation and serum testosterone level ≤1.73nmol / L (≤50ng / dL) at screening and before the start of treatment.

[0410] B4. Ongoing treatment with a next-generation AR signaling inhibitor (enzalutamide or abiraterone) initiated at least 90 days prior to screening and prior to initiation of treatment. A maximum of 30 days of interruption in medication was allowed before resuming medication.

[0411] B5. According to the PCWG3 study entry criteria, exacerbating disease is defined as one of the following:

[0412] Prostate-specific antigen (PSA) worsening, defined as two increases in PSA from the previous reference value, reaching a minimum value of ≥1 ng / mL before screening and treatment initiation (if the patient's abiraterone or enzalutamide dosing was interrupted for >14 days, an elevated PSA must be documented after resumption of the drug).

[0413] RECIST v 1.1 Exacerbation of soft tissue disease as defined.

[0414] A previously normal (<10 mm) lymph node must grow ≥5 mm in the short axis to be considered malignant.

[0415] A whole-body bone scan showing ≥2 new lesions was defined as bone disease worsening.

[0416] B6. Patients receiving bisphosphonates or denosumab for bone health must have been on a stable dose for at least 4 weeks prior to starting study treatment.

[0417] B7. Able to swallow oral medications and free from gastrointestinal disorders thought to compromise intestinal absorption (e.g., malabsorption, resection).

[0418] Exclusion criteria

[0419] Exclusion criteria were the presence of any of the following criteria that excluded the patient from participating in the study:

[0420] 1. Untreated or symptomatic central nervous system metastases, or requiring radiation, surgery, or continued steroid therapy to control symptoms within 14 days of study entry.

[0421] 2. Prior treatment with anti-ERBB3-directed therapy.

[0422] 3. Known involvement of the pia mater.

[0423] 4. Participated in another interventional clinical trial or received any investigational drug within 4 weeks before entering the study.

[0424] 5. Long-term use of high-dose oral corticosteroids (>10 mg prednisone equivalent per day).

[0425] 6. Uncontrolled hypertension (systolic blood pressure > 150 mmHg and / or diastolic blood pressure > 100 mmHg) or unstable angina.

[0426] 7. A history of congestive heart failure of New York Heart Association grade II-IV, or severe arrhythmia requiring treatment (except atrial fibrillation or paroxysmal supraventricular tachycardia).

[0427] 8. History of myocardial infarction within 6 months after entering the study.

[0428] 9. History of prior or concomitant malignancy (except resected non-melanoma skin cancer, cured in situ cervical cancer, or low-grade Ta or T1 bladder urothelial carcinoma that has received potentially curative treatment) within 3 years of study entry.

[0429] 10. Currently suffering from serious illness or health condition, including but not limited to: uncontrolled active infection, and clinically significant pulmonary, metabolic or psychiatric disease.

[0430] 11. Patients with the following known infectious diseases:

[0431] Known active hepatitis B infection (HBsAg positive) but not receiving antiviral therapy. Please note: Patients with active hepatitis B (HBsAg positive) must have received antiviral therapy with lamivudine, tenofovir, entecavir, or other antiviral drugs for at least ≥7 days prior to the start of study treatment. Patients with a history of hepatitis B (anti-HBc positive, HBsAg and hepatitis B virus [HBV] DNA negative) are eligible.

[0432] 12. Known human immunodeficiency virus (HIV)-positive patients, unless the CD4+ count is ≥300 / μL, the viral load is undetectable, and the patient is currently receiving highly active antiretroviral therapy.

[0433] Further exclusion criteria were the presence of any of the following criteria that excluded the patient from participating in the study:

[0434] 13. More than 2 second-generation hormonal drugs for the treatment of metastatic disease.

[0435] 14. Received more than 2 types of systemic chemotherapy for metastatic disease.

[0436] 15. Patients with only non-measurable disease other than bone metastases (e.g., pleural effusion, ascites, other visceral sites).

[0437] 16. Patients receiving enzalutamide have a history of epilepsy or any condition that may induce epileptic seizures in patients within 12 months prior to study treatment, including a history of unexplained loss of consciousness or transient ischemic attack.

[0438] Management of infusion-related reactions

[0439] Patients will be closely monitored during study treatment. Patients must be premedicated with antihistamines, paracetamol / acetaminophen, and corticosteroids prior to each infusion of zenoculumab.

[0440] Preventive and concomitant medications

[0441] Permitted drugs

[0442] The investigator may administer all medications necessary for the patient's health and not expected to interfere with the evaluation of the study drug, including supportive care for symptoms and AEs, or standard care for concomitant conditions.

[0443] Luteinizing hormone-releasing hormone (LHRH) agonists or antagonists were permitted in patients who had not undergone prior bilateral resection.

[0444] Prohibited drugs

[0445] Concomitant long-term oral corticosteroids (>10 mg / day prednisone equivalents), tumor necrosis factor (TNF)-α inhibitors, and anti-T-cell antibodies (due to the risk of immunosuppression).

[0446] Any study medication during the study or within 4 weeks prior to the first dose of study treatment.

[0447] Patients should not start new study medication for at least 4 weeks after their last dose of study medication.

[0448] Systemic anticancer therapy. Please note: For patients in Arm B, patients receiving next-generation AR signaling inhibitors immediately prior to study entry were permitted.

[0449] Efficacy Assessment: Response Measures, Tumor Measures

[0450] Radiographic measurements of tumors will be performed by CT scan or MRI to assess the antitumor effect of zenoculumab. Imaging will be performed according to local standards, and data will be collected in an electronic case report form. All patients' imaging studies will be reviewed by local investigators.

[0451] Brain MRI or CT scans should be performed with the same frequency as CT / MRI of the chest, abdomen, and pelvis and only if brain metastases are detected on the screening scan. Additional imaging of anatomical sites (e.g., head, neck) should be performed based on the patient's tumor type. Note that if there is a reason to evaluate bone lesions, these evaluations will be performed as part of the CT or MRI evaluation and no additional radiographic bone scan evaluation is required.

[0452] Additional scans may be performed to confirm response as appropriate. Any request for confirmatory scans will typically be performed at the next scheduled assessment time point or at a follow-up visit. A +3 day window is allowed for the first tumor assessment only. A ±3 day window is allowed thereafter but should be performed prior to the start of the next treatment cycle. Patients who discontinue treatment for reasons other than disease progression and do not withdraw consent will have disease status assessed every 8 weeks for up to 12 months until disease progression and / or initiation of new anticancer therapy or withdrawal of consent, whichever occurs first.

[0453] Whole-body bone scans will be performed every 8 weeks during the first 12 months of treatment and every 12 weeks thereafter. Tumor assessments will be completed according to PCWG3-modified RECIST criteria.

[0454] Tumor markers

[0455] PSA levels will be assessed prior to the start of treatment and on Day 1 of each cycle (every 4 weeks ± 3 days). Repeat assessments should be performed using the same laboratory.

[0456] The evolution of tumor marker levels will be followed throughout treatment.

[0457] Tumor tissue sample evaluation

[0458] PTEN analysis will be performed on baseline specimens (preferably fresh; archived specimens collected within 2 years are acceptable provided that they are collected after establishment of castration resistance) by IHC (local or central) or next generation sequencing to identify patients with PTEN wild-type status.

[0459] Example 3

[0460] According to the clinical trial process of Example 2, mCRPC patients with histologically confirmed prostate adenocarcinoma were recruited. After enrollment in the study, patients who were treated with abiraterone acetate or enzalutamide continued to use their backbone AR axis-targeted drugs and received zenocuzumab combination therapy. Sites involved in metastasis include lymph nodes, bones and / or visceral organs. When there is sufficient biological material, the patient's tumor PTEN status is established by IHC, using Roche Ventana Optiview kit DAB and SP218PTEN antibodies, using Benchmark Ultra immunohistochemistry automatic section staining machine. The OptiView DAB IHC detection kit (OptiView) is an indirect, biotin-free system for detecting mouse IgG, mouse IgM and rabbit primary antibodies. The kit is designed to identify targets in formalin-fixed, paraffin-embedded and frozen tissues by IHC, which are stained on the VENTANA automatic slide stainer and observed by light microscopy. The clinical interpretation of any staining or the absence of staining is supplemented by morphological studies and evaluation of appropriate controls.

[0461] No treatment-emergent adverse events (TEAEs) related to study treatment classified as Grade 3 TEAEs or higher were observed in the 10-patient cohort treated. In addition, the combination of zenocurizumab with abiraterone acetate or enzalutamide was well tolerated, and no safety issues were noted. In addition, there were no treatment discontinuations due to adverse events, and no unexpected toxicity signals were reported. Only a single IRR (i.e., Grade 2, related) was reported.

[0462] Example 4

[0463] According to the clinical trial process of Example 2, an 85-year-old male with mCRPC was treated with a combination of Zenocurizumab and enzalutamide. The patient had previously received a variety of systemic treatments, including two androgen receptor axis-targeted drugs (i.e., abiraterone and enzalutamide) and two chemotherapy (e.g., docetaxel and cabazitaxel), but showed disease progression after these treatments. Blood-based next-generation sequencing revealed nonsense mutations in NF1 (L1201*) and ERRFI1 (Y403*) and missense mutations in TP53 (V172D). According to the investigators' report, before the study was enrolled, the patient's imaging of the lymph nodes (LN) (target lesions) deteriorated slowly. During the study treatment, the patient showed the best overall response of stable disease according to RECIST (6 months), and showed no evidence of disease (NED) according to PCWG3 (6 months) bone scan, which was generally stable. After six months of continuous treatment, no evidence of lymph node deterioration was reported, which was consistent with radiological disease control.

[0464] Example 5

[0465] According to the clinical trial process of Example 2, a 77-year-old man with mCRPC was treated with a combination of Zenokuzumab and abiraterone acetate / prednisone. The patient had previously received four systemic treatments, including one chemotherapy and two androgen receptor axis-targeted drugs (i.e., darolutamide and abiraterone), but showed disease progression after these treatments. PTEN loss was observed by IHC testing of stored prostate specimens. The next generation sequencing test based on blood did not detect tumor-related somatic changes or mutations. According to the researchers' report, the patient had lymph node deterioration (non-target) and bone tissue metastasis before enrollment. In the study treatment, the patient had the best overall response: RECIST disease stability (4 months) and PCWG3 bone scan disease stability (4 months), overall stability. After five months of continuous treatment, no evidence of lymph node or bone deterioration was reported, which was consistent with radiological disease control.

[0466] Example 6

[0467] According to the clinical trial protocol of Example 2, a 77-year-old male with mCRPC was treated with a combination of Zenoculumab and Enzalutamide. The patient had previously received multiple systemic therapies, including chemotherapy, radiopharmaceuticals, and chemotherapy. and androgen receptor axis-targeted drugs such as docetaxel, abiraterone (in combination with prednisone), and enzalutamide, but showed disease progression after these treatments. IHC testing of archived tumor samples from previous prostate biopsies showed that the patient's tumor was PTEN wild-type. Only missense mutations were detected in TP53 (A161T) and nonsense mutations were detected in APC (K139*) by blood-based next-generation sequencing. Based on study treatment, the patient achieved a best overall response of stable disease as measured by target lesions (lymph nodes) according to RECISTv1.1, according to investigator reports. Patients discontinued treatment in the event of a skeletal-related event.

[0468] Example 7

[0469] According to the clinical trial process of Example 2, two additional patients whose PTEN status was wild-type using IHC testing were treated with a combination of Zenoculumab and Enzalutamide. According to the PCWG3 criteria, PSA values ​​will be evaluated at least 12 weeks after the start of treatment to understand the trend of improvement. Imaging studies will be performed at pre-specified time points within the same time frame to assess radiological disease control. These patients have previously received a variety of systemic therapies, including chemotherapy and androgen receptor axis-targeted drugs, such as abiraterone, docetaxel (docetaxel) in combination with bicalutamide (bicalutamide); cabazitaxel (cabazitaxel) or prednisone (prednisone) in combination with Enzalutamide, but all showed disease progression after these treatments.

Claims

1. A bispecific antibody comprising an antigen binding site that binds to an extracellular portion of ERBB2 and an antigen binding site that binds to an extracellular portion of ERBB3, for use in a method of treating castration-resistant prostate cancer in an individual.

2. A method for treating an individual with castration-resistant prostate cancer, the method comprising administering to the individual a therapeutically effective amount of a bispecific antibody comprising an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3.

3. The bispecific antibody for use or method of claim 1 or 2, wherein the cancer has progressed after prior treatment with an androgen receptor axis-targeting agent.

4. The bispecific antibody for use or method of claim 3, wherein the androgen receptor axis-targeting agent is an androgen receptor antagonist, such as a second generation androgen receptor antagonist.

5. The bispecific antibody for use or method of claim 4, wherein the androgen receptor antagonist is enzalutamide.

6. The bispecific antibody for use or method of claim 3, wherein the androgen receptor axis-targeting agent is an androgen synthesis inhibitor, such as abiraterone acetate.

7. The bispecific antibody for use or method of any of the preceding claims, wherein the method of treatment further comprises the use of an androgen receptor axis-targeting agent.

8. The bispecific antibody for use or method of any one of claims 1 to 6, wherein the method of treatment further comprises the use of an androgen receptor antagonist, such as a second generation androgen receptor antagonist, such as enzalutamide.

9. The bispecific antibody for use or method according to any one of claims 1 to 6, wherein the method of treatment further comprises the use of an androgen synthesis inhibitor, such as abiraterone acetate.

10. The bispecific antibody for use or method of any one of claims 1 to 4, wherein the cancer has progressed after previous treatment with an androgen receptor antagonist, and the method of treatment using the bispecific antibody further comprises the use of an androgen receptor antagonist.

11. The bispecific antibody for use or method of claim 10, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody are the same.

12. The bispecific antibody for use or method according to claim 10 or 11, wherein the androgen receptor antagonist used in the previous treatment and the androgen receptor antagonist further used in the method of treatment using the bispecific antibody are both enzalutamide.

13. The bispecific antibody for use or method of claim 8 or 12, wherein enzalutamide is administered once daily at 160 mg.

14. The bispecific antibody for use or method of any one of claims 1 to 3 or claim 6, wherein the cancer has progressed following previous treatment with an androgen synthesis inhibitor, and the method of treatment using the bispecific antibody further comprises the use of an androgen synthesis inhibitor.

15. The bispecific antibody for use or method of claim 14, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody are the same.

16. The bispecific antibody for use or method according to claim 14 or 15, wherein the androgen synthesis inhibitor used in the previous treatment and the androgen synthesis inhibitor further used in the method of treatment using the bispecific antibody are both abiraterone acetate.

17. The bispecific antibody for use or method as claimed in claim 9 or 16, wherein abiraterone acetate is administered once daily at 1000 mg.

18. The bispecific antibody for use or method of claim 17, wherein abiraterone acetate is administered in combination with 5 mg prednisone twice daily.

19. The bispecific antibody for use or method according to any one of the preceding claims, wherein the method of treatment comprises administering the bispecific antibody in an amount of 750 mg once every two weeks.

20. The bispecific antibody for use or method of any one of the preceding claims, wherein the cancer is not NRG1 fusion positive.

21. The bispecific antibody for use or method of claim 7, wherein the androgen receptor axis-targeting agent is administered according to a medical prescription indication established by a health authority such as the FDA.

22. The bispecific antibody for use or method of any of the preceding claims, wherein the cancer is characterized as histologically confirmed prostate adenocarcinoma without neuroendocrine differentiation or small cell features.

23. The bispecific antibody for use or method of any preceding claim, wherein the bispecific antibody comprises a first antigen binding site that binds to domain I of ERBB2, and a second antigen binding site that binds to domain III of ERBB3.

24. A bispecific antibody for use or method as claimed in any one of the preceding claims, wherein the bispecific antibody comprises i) at least CDR1, CDR2 and CDR3 sequences in an ERBB2-specific heavy chain variable region selected from the group consisting of: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, Or wherein the antibody comprises a CDR sequence that differs from the following CDR1, CDR2, and CDR3 sequences by at most 3 amino acids, preferably at most 2 amino acids, preferably at most 1 amino acid: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or ii) at least CDR1, CDR2 and CDR3 sequences in an ERBB3-specific heavy chain variable region selected from the group consisting of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, Or wherein the antibody comprises a CDR sequence that differs from the following CDR1, CDR2, and CDR3 sequences by at most 3 amino acids, preferably at most 2 amino acids, preferably at most 1 amino acid: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

25. A bispecific antibody for use or method as claimed in any one of the preceding claims, wherein the bispecific antibody comprises i) an ERBB2-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 and MF3003, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the heavy chain variable region sequence of MF2973, MF3004, MF3958, MF2971, MF3025, MF2916, MF3991, MF3031 or MF3003; and / or ii) an ERBB3-specific heavy chain variable region sequence selected from the group consisting of the following heavy chain variable region sequences: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 and MF6074, or wherein the antibody comprises a heavy chain variable region sequence that differs by at most 15 amino acids from the heavy chain variable region sequence of: MF3178; MF3176; MF3163; MF6055; MF6056; MF6057; MF6058; MF6059; MF6060; MF6061; MF6062; MF6063; MF6064; MF 6065; MF6066; MF6067; MF6068; MF6069; MF6070; MF6071; MF6072; MF6073 or MF6074.

26. The bispecific antibody for use or method of any of the preceding claims, wherein the bispecific antibody comprises the heavy chain variable region sequences of MF3958 and MF3178.

27. The bispecific antibody for use or method of any one of claims 1, wherein the bispecific antibody comprises a variable domain comprising the first antigen binding site and a variable domain comprising the second antigen binding site, and wherein the first and second antigen binding sites comprise a light chain variable region comprising a CDR1 comprising the sequence QSISSY, a CDR2 comprising the sequence AAS, and a CDR3 comprising the sequence QQSYSTPPT.

28. The bispecific antibody for use or method of any one of the preceding claims, wherein the subject is a human subject.

29. The bispecific antibody for use or method of any one of the preceding claims, wherein the cancer is metastatic castration-resistant prostate cancer, or wherein the individual is at risk of developing metastatic castration-resistant prostate cancer.

30. A kit of parts comprising a bispecific antibody and an androgen receptor axis-targeting agent, wherein the bispecific antibody comprises an antigen binding site that binds to the extracellular portion of ERBB2 and an antigen binding site that binds to the extracellular portion of ERBB3.

31. The multi-component kit of claim 30, further comprising instructions for use.

32. The kit of parts of claim 30 or 31, wherein the instructions for use include instructions for administering the bispecific antibody and the androgen receptor axis-targeting agent.

33. The multi-component kit of any one of claims 30 to 32, wherein the androgen receptor axis-targeting agent comprises an androgen receptor antagonist such as a second generation androgen receptor antagonist such as enzalutamide, or comprises an androgen synthesis inhibitor such as abiraterone acetate, and wherein the bispecific antibody comprises zenocutuzumab.

34. The kit of parts according to claim 33, wherein the instructions for use include administering abiraterone acetate at 1000 mg once daily in combination with prednisone at 5 mg twice daily, and administering the bispecific antibody at an amount of 750 mg once every two weeks.

35. The kit of parts of claim 33, wherein the instructions for use comprise administering 160 mg of enzalutamide once daily and administering 750 mg of the bispecific antibody once every two weeks.

36. The kit of parts of claim 34 or 35, wherein the instructions for use of the abiraterone acetate or enzalutamide include instructions for oral administration, and administration of the bispecific antibody includes instructions for intravenous injection.

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