A Study of M701 (EpCAM and CD3) in Malignant Ascites

Inclusion Criteria: 1. Males or females, aged \> 18 years; 2. Histologically- or cytologically-confirmed advanced solid tumors; 3. Patients who require therapeutic paracentesis, defined as at least 1 therapeutic paracentesis (e.g., to relieve abdominal pressure and discomfort) during 4 weeks prior to the baseline paracentesis; 4. Patients who have failed to standard treatment, or who have no standard treatment available that may confer clinical benefit; 5. EpCAM+ tumor cells in ascites fluid; 6. Patients who have received anti-tumor therapy including chemotherapy, hormone therapy, radiotherapy (except local radiotherapy for pain relief) ≥ 2 weeks or received immunotherapy, biological agents ≥ 3 weeks prior to the first dose of study drug; 7. Patients who have recovered from any toxic reaction to previous medications (Grade 0 or 1 based on NCI-CTCAE v5.0); 8. Patients with an ECOG Performance Status score (PS) 0-3; 9. Patients with a life expectancy \> 8 weeks; 10. Organ function levels must meet the following requirements: Bone marrow: absolute neutrophil count (ANC) ≥ 1.5 ×10\^9/L, platelet count ≥ 80 ×10\^9/L, hemoglobin ≥ 9.0 g/dL (without blood transfusion within14 days of the first dose of study drug); Liver: bilirubin ≤ 1.5 x upper limit of normal (ULN), aspartate aminotransferase (AST) and alanine transaminase (ALT) ≤ 3 x ULN ( ≤ 5 x ULN in case of liver metastases); Kidney: serum creatinine ≤1.5 x ULN and estimated glomerular filtration rate (eGFR) ≥ 50 ml/min; 11. Patients must understand and voluntarily sign the informed consent form. Exclusion Criteria: 1. Known to have a history of allergy to the active ingredients of M701; or with a definite history of drug allergy or specific allergy (asthma, rubella, eczema dermatitis); 2. Known or suspected hypersensitivity to M701 or similar antibodies; 3. Extensive liver metastases (\> 70% organ volume comprises malignancy); 4. Uncontrolled active infection (CTCAE ≥ Grade 2); 5. Serious diarrhea (CTCAE ≥ Grade 2); 6. Serious dyspnea requiring oxygen therapy; 7. History of auto-immune diseases (e.g. inflammatory bowel disease, idiopathic thrombocytopenic purpura, lupus erythematosus, autoimmune hemolytic anemia, scleroderma, serious psoriasis, rheumatoid arthritis); 8. History of acute or chronic pancreatitis; 9. Other serious diseases that may prevent patients participation in this trial (such as uncontrolled diabetes mellitus, severe gastrointestinal disorders); 10. Cardiac insufficiency, NYHA class III or IV; 11. Intestinal obstruction that occurred within 30 days prior to the first dose of study drug; 12. Non-drainable ascites; 13. Confirmed portal vein obstruction; 14. History of immunodeficiency, including positive HIV test; 15. Active hepatitis B virus infection or hepatitis C virus infection, positive syphilis antibody test and positive HIV antibody test; 16. Pregnant or breastfeeding woman; 17. Plan to conceive within six months; 18. Previous confirmed history of neurological or mental disorders, including epilepsy and dementia; 19. Have received a clinical study active drug treatment within 1 month prior to the first dose of study drug; 20. Those that are deemed ineligible for this clinical trial by study personnel.