A Clinical Study of GO306 in Patients With Advanced Solid Tumors

Inclusion Criteria: * Age 18 years old and above, regardless of gender. * Patients with histologically or cytologically confirmed advanced malignant solid tumors, including but not limited to breast cancer, bladder urothelial cancer, colorectal cancer, renal cancer, ovarian epithelial cancer, and neuroendocrine tumors, who have no response or failure to standard treatment (including disease progression and/or intolerable side effects), or no standard treatment. Examples are as follows: * a. Histologically or cytologically confirmed unresectable or metastatic bladder urothelial carcinoma: failure to or intolerance to prior platinum-based chemotherapy and PD-1/PD-L1 inhibitors or no available standard treatment options for unresectable or metastatic disease. * b. Patients with histologically or cytologically confirmed recurrent ovarian cancer with malignant ascites who have received at least one previous line of platinum-based chemotherapy-based therapy and no available standard treatment options, and those with germline or somatic BRCA mutations who failed or did not tolerate PARP inhibitors. * c. Histologically or cytologically confirmed unresectable or metastatic colorectal cancer with liver metastases: failure or intolerance to prior oxaliplatin, fluorouracil, and irinotecan based therapy (or PD-1/PD-L1 inhibitors if the patient is MSI-H/dMMR) or no standard treatment options are available. * d. Patients with histologically or cytologically confirmed unresectable or metastatic clear-cell renal carcinoma with prior failure to, or intolerance to, Tkis and PD-1/PD-L1 inhibitors or no available standard treatment options for unresectable or metastatic clear-cell renal carcinoma. * e. Histologically or cytologically confirmed, locally advanced or metastatic triple-negative breast cancer: failure to or intolerance to at least one previous line of standard chemotherapy, which must include a taxane (e.g., paclitaxel, docetaxel), or no standard treatment options available. * f. For patients with neuroendocrine tumors, one of the following criteria must be met: * (1) Patients with histologically confirmed advanced stage (inoperable locally advanced or distant metastasis) with Ki-67≥55% in G3 NET and NEC (including mixed neuroendocrine and non-neuroendocrine tumors \[at least 30% neuroendocrine carcinoma component\], excluding small cell lung cancer and Meckel cell carcinoma) : They have failed or are intolerant to at least one previous line of standard chemotherapy (EP or EC), or no standard treatment options are available. * (2) Histologically confirmed advanced NET G3 patients (unresectable locally advanced or distant metastasis) and atypical pulmonary and mediastinal carcinoid patients: patients who had received at least second-line standard treatment failed or could not tolerate it, and the treatment regimen must include CAPTEM regimen or no available standard treatment regimen. * g. Histologically or cytologically confirmed advanced solid tumors (other than the above, e.g., soft tissue sarcoma, etc.) : documented disease progression or intolerance during or after receiving previous standard therapy, or no standard treatment options are available. * Patients with ovarian cancer and solid malignant tumors of the digestive tract with malignant ascites who plan intracavitary injection should meet the following requirements: * a. Malignant ascites was pathologically diagnosed as caused by the spread of cancer cells. * b. Grade ≥2 ascites recurred within 4 weeks after receiving at least one local treatment (including paracentesis, intraperitoneal chemotherapy, intraperitoneal venous shunt, hyperthermic intraperitoneal perfusion, etc.). * c. Massive peritoneal effusion confirmed by computed tomography (CT) or B-ultrasound, which clinically requires local treatment for peritoneal effusion. * At least one lesion that could be evaluated, as confirmed by local imaging, according to RECIST 1.1 criteria. Intratumoral injectable lesion, with or without CT/ ultrasound guidance, was defined as a palpable or CT/ ultrasound visible skin, subcutaneous, or deep mass with a major diameter ≥1.5cm (in the case of a lymph node, a short diameter ≥1.5cm) amenable to CT/ ultrasound guidance for intratumoral injection, as judged by the investigator. The injection site was required to have not been treated with radiation. * Eastern Cooperative Oncology Group (ECOG) score ≤2. * Expected survival time ≥3 months. * The subjects had adequate organ function at the baseline of the screening period, and the laboratory indicators met the following criteria: * a. Hematopoietic system (no previous blood transfusion or hematopoietic stimulating factor therapy within 14 days) : absolute neutrophil count (ANC) ≥1.5×109/L; Hemoglobin (Hgb) ≥90g/L; Platelet count (Plt) ≥75×109/L. * b. Liver function: serum total bilirubin (TBIL) ≤1.5×ULN, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3×ULN, with liver metastasis TBIL≤3×ULN, ALT and AST≤5×ULN; Serum albumin ≥2.8 g/dL (subjects could use albumin to meet criteria). * c. Renal function: serum creatinine (Cr) ≤1.5×ULN or creatinine clearance (according to Cockroft-Gault formula) \>50mL/min. * d. Coagulation: international normalized ratio (INR) ≤1.5, activated partial thromboplastin time (APTT) ≤1.5×ULN. * Participants were willing and able to comply with protocol requirements for the duration of the trial, including but not limited to receiving treatment, using effective contraception (for 3 months after dose), and undergoing regular follow-up and examinations. Exclusion Criteria: * Female subjects who were pregnant or lactating. * Patients who had received a diagnosis of another malignancy within the previous 2 years, except for cancers with a low risk of metastasis and death (5-year survival rate, \>90%), such as adequately treated basal-cell or squamous-cell skin cancer or carcinoma in situ of the cervix and other cance