Sacituzumab Tirumotecan in Combination With Tagitanlimab in the Treatment of Aggressive Variant Prostate Cancer (AVPC) and Neuroendocrine Prostate Cancer (NEPC)

Inclusion Criteria: 1. Age at the time of signing the informed consent form is ≥ 18 years old; 2. AVPC or NEPC diagnosed based on recent histological and/or clinical criteria; 3. Having received one or two second-generation anti androgen therapies in the past, previous use of docetaxel for castration resistant prostate cancer (CRPC) is allowed, and the use of other chemotherapy is not allowed; 4. The progression of prostate cancer in the subjects within 6 months prior to screening shall be determined by the researcher through one of the following methods: PSA is evaluated by local laboratories, and PSA progression is defined as at least two increases in PSA levels at intervals of ≥ 1 week, with a screening PSA value of ≥ 2 ng/ml. • Soft tissue imaging disease progression determined based on PCWG modified RECIST 1.1 or RECIST 1.1 criteria, regardless of PSA progression. The imaging disease progression of bones is defined as the appearance of two or more new bone lesions in bone scans, regardless of PSA progression. 5. Subjects who have not undergone past surgery must be using and voluntarily continue to use luteinizing hormone releasing hormone (LHRH) agonists throughout the entire study treatment period; 6. According to RECIST v1.1, there should be at least one measurable lesion, and previously irradiated lesions should not be selected as target lesions; Subjects with only skin or bone lesions are not eligible for inclusion; 7. Within 7 days prior to administration, the physical fitness status score of the Eastern Cooperative Oncology Group (ECOG) in the United States was 0 or 1; 8. Expected survival period ≥ 12 weeks; 9. Having sufficient organ and bone marrow function (without receiving blood transfusion, recombinant human thrombopoietin or colony-stimulating factor therapy within 2 weeks prior to administration), defined as follows: 1. Blood routine: neutrophil count (NEUT #) ≥ 1.5 × 109/L; platelet count (PLT) ≥ 100 × 109/L; hemoglobin ≥ 90 g/L; 2. Liver function: Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN; For subjects with liver metastasis at baseline, ALT and AST should be ≤ 5 × ULN; Albumin ≥ 30g/L; Total bilirubin (TBIL) ≤ 1.5 × ULN; 3. Renal function: creatinine clearance rate ≥ 50 ml/min (calculated using the standard Cockcroft Gault formula); 4. Coagulation function: International normalized ratio (INR), activated partial thromboplastin time (APTT), and prothrombin time (PT) ≤ 1.5 × ULN; 10. For subjects whose partners have fertility potential, they must agree to take effective medical contraceptive measures within 6 months from the signing of the informed consent form until the last administration (see Annex 2 for details); 11. The subjects voluntarily joined this study, signed an informed consent form, and were able to comply with the visit and related procedures specified in the protocol. Exclusion Criteria: 1. Previously received any of the following treatments (including in the context of adjuvant or neoadjuvant therapy): 1. Targeted treatment of TROP2; 2. Any drug therapy containing targeted topoisomerase I, including antibody conjugated drug (ADC) therapy; 3. Immune checkpoint inhibitors (such as anti-PD-1/L1 antibodies, anti-CTLA-4 antibodies, etc.), immune checkpoint agonists (such as ICOS, CD40, CD137, GITR, OX40 antibodies, etc.), immune cell therapy, and any other treatment targeting the tumor immune mechanism; 2. Those who require the use of strong inhibitors or inducers of cytochrome P450 3A4 enzyme (CYP3A4) within 2 weeks prior to the first administration and during the study period (strong inhibitors or inducers of CYP3A4 are not allowed in this study, and representative drugs of CYP3A4 strong inhibitors or inducers are listed in Appendix 7); All subjects must avoid the concurrent use of any drugs, herbal supplements, and/or intake of such foods known to induce CYP3A4 as much as possible; 3. Subjects with central nervous system (CNS) metastases known to have meningeal metastases, brainstem metastases, spinal cord metastases and/or compression, active or untreated conditions. For subjects with brain metastases who have received local treatment in the past, if they have been clinically stable for at least 4 weeks before medication and have not required the use of glucocorticoids or anticonvulsants for at least 14 days, they are allowed to be enrolled; 4. Suffering from other malignant tumors within 3 years before administration (excluding tumors that have been cured through local treatment, such as basal cell carcinoma of the skin, squamous cell carcinoma of the skin, cervical carcinoma in situ, etc.); 5. There are any of the following cardiovascular diseases or cardiovascular risk factors: 1. Within 6 months prior to administration, if there is a myocardial infarction, unstable angina, acute or persistent myocardial ischemia, grade 3 or 4 heart failure (according to the New York Heart Association (NYHA) classification), symptomatic or poorly controlled severe arrhythmia, cerebrovascular accident, transient ischemic attack, or other serious cardiovascular and cerebrovascular diseases; 2. Previous history of myocardial diseases such as myocarditis, primary cardiomyopathy, and specific cardiomyopathy; 3. Any deep vein thrombosis (if stabilized for ≥ 2 weeks with low molecular weight heparin or similar efficacy drugs), peripheral arterial thromboembolic events, pulmonary embolism, or other serious thromboembolic events within 3 months prior to administration; 4. Major vascular diseases that may endanger life or require surgery within 6 months prior to administration, such as aortic aneurysm, aortic dissection aneurysm, etc; 6. According to researchers' assessment, uncontrolled systemic diseases: 1. Poor control of diabetes (fasting blood glucose ≥ 10 mmol/L for two consecutive times); 2. Poor control of hypertension (systolic blood pressure\>160 mmHg and/or diastolic bloo