This is a multicenter, open-label, first-in-human (FIH) study to evaluate the safety, tolerability, efficacy and pharmacokinetic/pharmacodynamic characteristics of SIM0613 in participants with locally advanced/ metastatic solid tumors. The study starts with a dose escalation part (Part 1) followed by a dose expansion part (Part 2).

Inclusion Criteria:

1. Written informed consent (ICF) is obtained prior to any of the specified procedures required for the study
2. ≥18 years of age
3. Histologically or cytologically confirmed locally advanced/metastatic solid tumors
4. Have at least one measurable disease per RECIST Version 1.1 criteria
5. Have experienced disease progression on/after at least one accessible standard therapy, or are intolerant to standard therapy, or are not suitable for standard therapy, or for whom clinical trial of the investigational drug serves as standard treatment
6. Life expectancy of ≥12 weeks
7. Have adequate organ function
8. Women of childbearing potential (WOCBP) must have a negative serum pregnancy test within 3 days prior to the start of study treatment.
9. For Part 1, archival or fresh tumor tissue sample (preferably 12 with a minimum number of 10 sections) should be collected if available at Biomarker-screening or screening visit. For Part 2, it is mandatory to collect archival tumor tissue sample (preferably 12 with a minimum number of 10 sections) performed within 6 months prior to consent or fresh tumor tissue sample at Biomarker-screening or screening visit

Exclusion Criteria：

1. Any other malignancy within 2 years prior to the first dose of the study treatment except for localized cancers that are considered to have been cured and in the opinion of the Investigator present a low risk for recurrence (e.g., basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the prostate, cervix or breast)
2. Participants with symptomatic central nervous system (CNS) metastases, or CNS metastases requiring CNS-directed local therapy (such as radiotherapy or surgery), or CNS metastases requiring corticosteroids therapy within 2 weeks of first dose of study treatment.
3. History of bowel obstruction within 3 months prior to the first dose of study treatment.
4. Known psychiatric disorder or drug abuse that would interfere the study requirements
5. Uncontrollable pleural effusion, pericardial effusion, or ascites requiring drainage or medical intervention within 4 weeks before the first dose of study treatment
6. Any active infection requires systemic treatment via intravenous infusion within 2 weeks prior to the first dose of study treatment
7. Has not recovered (i.e., to Grade 1 or to baseline) from previous anticancer therapy-induced AEs.
8. Participant is currently participating or has participated in a study of an investigational agent or using an investigational device within 4 weeks of first dose of SIM0613.
9. Major surgery within 2 weeks of receiving the first dose of study treatment (minor procedures such as mediastinoscopy, insertion of a central venous access device, insertion of a feeding tube, needle biopsy and percutaneous nephrostomy are not considered major surgery)
10. Prior exposure to topoisomerase I (TOP-I) inhibitor inhibitor-based antibody-drug conjugate (ADC) therapies or LRRC15-targeted therapies.
11. Use of any live vaccine therapy within 4 weeks prior to the first dose of study treatment
12. Known human immunodeficiency virus (HIV) infection or known acquired immunodeficiency syndrome (AIDS)
13. Active hepatitis B (HBsAg or HBcAb positive）
14. History of allogeneic organ transplantation or graft-versus-host disease
15. Known hypersensitivity to study drug or any of the excipients
16. Participant is pregnant or breastfeeding
17. Other conditions that researchers consider inappropriate for inclusion.