The purpose of this study is to examine tolerability, safety, and pharmacokinetics of YS110 intravenous administration in patients with malignant pleural mesothelioma and to preliminarily examine the anti-tumor effect of YS110.

Inclusion Criteria:

• Patient with male or female aged ≥ 20 (and aged < 75 in Phase 1 part)
• Patients whose malignant pleural mesothelioma was histologically confirmed
• Patients who have advanced pleural mesothelioma that are refractory to existing anti-tumor drugs and who have no other standard therapies which should be prioritized
• Patients whose most recent major surgery (except exploratory thoracotomy or laparotomy) or drug or radiation therapy for malignant tumors, if any, was at least 4 weeks ago (at least 12 weeks ago for immunotherapy) at the subject enrollment
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 1 or less

Exclusion Criteria:

• Patients whose toxicity findings in the previous treatment (antineoplastic agents) have not been yet restored
• Patients with tumor lesions in central nervous system confirmed in MRI or CT