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 therapeuticparacentesis (e.g., to relieve abdominal pressure and discomfort) during 4 weeks priorto the baseline paracentesis;

4. Patients who have failed to standard treatment, or who have no standard treatmentavailable 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 receivedimmunotherapy, 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 0or 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 firstdose of study drug); Liver: bilirubin ≤ 1.5 x upper limit of normal (ULN), aspartateaminotransferase (AST) and alanine transaminase (ALT) ≤ 3 x ULN ( ≤ 5 x ULN in case ofliver metastases); Kidney: serum creatinine ≤1.5 x ULN and estimated glomerularfiltration 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 adefinite history of drug allergy or specific allergy (asthma, rubella, eczemadermatitis);

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, idiopathicthrombocytopenic 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 asuncontrolled 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 studydrug;

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 syphilisantibody 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 anddementia;

19. Have received a clinical study active drug treatment within 1 month prior to the firstdose of study drug;

20. Those that are deemed ineligible for this clinical trial by study personnel.