Dose Escalation and Cohort Expansion Study of YS-ON-001 in Patients With Advanced Solid Tumors

Inclusion Criteria:

* Life expectancy ≥ 3 months
* Patient with histologically or cytologically proven advanced (unresectable) or metastatic solid tumor who have failed standard therapies or are intolerant to standard therapies.Part 1: Any advanced or metastatic solid tumor patient Part 2: Selected tumor types including cytological or histologically diagnosed breast cancer and liver cancer
* Patients with adequate bone marrow function, with absolute neutrophil count (ANC) \>1,500/mm3, platelet count \>100,000/mm3, and hemoglobin \> 10 g/mm3
* Patients with adequate kidney function, with serum creatinine ≤1.5 X upper limit of normal (ULN)
* Patients with adequate liver function, with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5x ULN, total bilirubin ≤1.5x ULN ; For patients with liver metastasis, AST, ALT ≤5x ULN, Total bilirubin ≤1.5x ULN
* Patients with adequate coagulation function, with activated partial thromboplastin time (aPTT) ≤1.5x ULN
* Female patients, if of childbearing potential, must have a negative serum pregnancy test within 72 hours prior to the date of the first dose of study medication.
* Female patients of childbearing potential and male patients must agree to use adequate methods of contraception with their partner starting with the screening visit up to 4 weeks after the last dose of study therapy.
* Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2.

Exclusion Criteria:

* Known uncontrolled seizures, central nervous system disorders, or loss of cognitive ability due to mental illness
* Pregnant or breastfeeding, or expecting to conceive children within the projected duration of the study.
* Patient is currently receiving or has received systemic corticosteroids within 2 weeks prior to starting study drug, or who have not fully recovered from side effects of such treatment. The following use of corticosteroids are permitted: single doses, topical applications (e.g., for rash), inhaled sprays (e.g., for obstructive airway diseases), eye drops or local injections (e.g., intra-articular).
* Known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies).
* Known serious, uncontrolled medical conditions that in the opinion of the investigator, will render it unsafe for the patient to receive the study therapy
* Active autoimmune disease that has required systemic treatment in the past 2 years (i.e., with use of disease-modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment.
* Patient has not recovered (i.e., to ≤ Grade 1 or to baseline) from radiation- and chemotherapy-induced adverse events (AEs) or administration of colony-stimulating factors (including granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF) or recombinant erythropoietin) within 3 weeks prior to the first dose of study drug.
* Currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational drug within 4 weeks prior to the first dose of study drug.
* Received prior anticancer therapy (chemotherapy, targeted therapies, radiotherapy, or immunotherapy) within 21 days, or less than 5 times the half-life of the most recent therapy prior to study Day 1, whichever is shorter. Note: palliative radiation therapy to a small field ≥ 1 week prior to Day 1 of study treatment will be allowed.
* Patient has not recovered adequately (≤ Grade 1) from AEs and/or complications from any major surgery prior to starting therapy. Patient has received a vaccine within 7 days of planned start of study therapy.
* Known hypersensitivity to YS-ON-001 components or excipients
* Known unstable systemic disease including active infection, uncontrolled hypertension, unstable angina, congestive heart failure, myocardial infarction that occurred within a year, severe arrhythmia that required drug treatment, liver disease, kidney disease and metabolic diseases)
* Known history of splenectomy
* Known history of chronic alcohol or drug abuse within 6 months
* PI assessment of subject's lack of willingness to participate and comply with all requirements of the protocol
* Any other finding which, in the opinion of the PI would significantly increase the risk of having an adverse outcome from participating in this protocol.