Clinical Study of PM1003 in Phase I/IIa Treatment of Advanced Malignant Solid Tumors

Inclusion Criteria: 1. Voluntary participation in clinical study; fully understand the study and sign informed consent voluntarily; willing to follow and able to complete all test procedures; 2. Male or female aged 18 to 75 years; 3. Subjects with malignant tumor confirmed by histology or cytology; 4. Adequate organ function; 5. ECOG score was 0-1. 6. Pre-menopausal female subjects with negative blood pregnancy results within 7 days prior to the study treatment, and agree to abstain from sex or use medically approved effective contraceptive measures for 6 months from the date of signing the informed consent form to the end of the last medication; 7. Male subjects are agree to abstain from sex or use medically approved effective contraceptive methods for 6 months from the date of signing the informed consent form to the end of the last medication, and do not donate sperm during this period. Exclusion Criteria: 1. History of severe allergic to macromolecular protein drugs, severe allergy to drugs or known allergy to any component of the drug in this study; 2. Treatment with any 4-1BB monoclonal antibody or 4-1BB-containing dual antibody immune co-stimulatory molecule agonist; 3. Current active infection requiring intravenous anti-infective therapy; 4. Current presence of uncontrolled pleural, pericardial, and peritoneal effusions; 5. Known history of alcohol abuse, psychotropic drug abuse or drug abuse; 6. History of neurological or psychiatric disorders, such as epilepsy, dementia, schizophrenia, etc.; 7. Anticipated need for any other form of antineoplastic drug treatment during the trial; 8. Women who are pregnant or breastfeeding; 9. Other conditions lead to inappropriate to participate in this study as judged by the investigator.