Aims to Explore the Safety, Tolerability, and Preliminary Efficacy of SCTB41 in Adult Patients with Advanced Malignant Solid Tumours.

A Phase I/II, Open-label, Multicentre, Dose-escalation, and Dose-expansion Study to Evaluate the Safety, Pharmacokinetics and Anti-tumor Activity of SCTB41 in Patients with Advanced Malignant Solid Tumours

This study aims to explore the safety, tolerability, PK characteristics, immunogenicity, and preliminary anti-tumor efficacy of SCTB41 as a monotherapy in adult patients with advanced malignant solid tumours. This study is an open label, multicentre, dose-escalation and dose-expansion Phase I/II clinical trial.

Inclusion Criteria:

1. Voluntarily sign the informed consent form (ICF);
2. Male or female, ≥18 years old;
3. Survival duration more than 3 months;
4. ECOG score ≤ 1 point;
5. Participants in Phase Ia (dose-escalation phase) are required to meet the following criteria: histologically or cytologically confirmed diagnosis of advanced malignant solid tumour;
6. Participants in Phase Ib (dose-expansion phase) and Phase II are required to meet the following criteria: Histologically or cytologically confirmed specific type advanced malignant solid tumours;
7. Adequate organ and bone marrow function.

Exclusion Criteria:

1. Participants with brainstem, meningeal, spinal metastases, orcompression; active central nervous system metastases;
2. Other malignancies diagnosed;
3. History of hypertensive crisis or hypertensive encephalopathy; presence of uncontrolled hypertension. History of arterial thrombosis or deep veinthrombosis within 6 months prior to enrollment;
4. Presence of any active autoimmune disease or a history of autoimmunedisease with an expected recurrence;
5. Received chemotherapy, immunotherapy, biologic therapy, or other antitumor treatments within 4 weeks before enrollment;
6. Need for immunosuppressive drugs within 2 weeks prior to enrollment oranticipated during the study;
7. Significant coagulopathy or other evident risk of bleeding;
8. uncontrolled effusions in the serous cavities within 4 weeks before enrollment；
9. Major surgery or significant trauma within 4 weeks prior to enrollment;presence of unhealed skin wounds, surgical sites, trauma sites, severe- Page 3 of 4 [DRAFT] -mucosal ulcers, or fractures, or if the Investigator deems the participantunsuitable for the study;
10. History of permanent discontinuation of immunotherapy due to immunerelated toxicity or occurrence of ≥ Grade 3 irAEs;
11. Known severe allergy to similar antibody drugs;
12. Presence of active infection；
13. History of organ transplantation or stem cell transplantation;
14. Pregnant or breastfeeding female; women of childbearing potential withpositive pregnancy test within 7 days before the enrollment; participants(including males of childbearing potential and their female partners, and females of childbearing potential and their male partners) unwilling to use medically recognized effective contraception during the study and for 6 months after treatment ends.