A Study of ONO-4538HSC in Pediatric Patients With Malignant Solid Tumors and in Patients With Epithelioid Sarcoma.

Prior treatment

• Patients with current or previous severe hypersensitivity reactions to antibody products
• Patients who have previously received anti-PD-1 antibody, anti-PD-L1 antibody, anti-PD-L2 antibody, anti-CD137 antibody, anti-CTLA-4 antibody, or other therapeutic antibodies or pharmacotherapies for regulation of T cells

Other illness

• Patients with multiple cancers

Other

• Patients with primary central nervous system tumor
• Patients with brain or meningeal metastases. However, patients who are asymptomatic and do not require treatment can be enrolled.

• \[Cohort of pediatric malignant solid tumor Tolerability evaluation part\]
• Patients aged ≥ 12 to \< 18 years at the time of signing the informed consent form (ICF)
• Patients with radically/curatively unresectable advanced or metastatic solid tumor who are refractory to or intolerant to standard treatment or for which no standard treatment is available.
• Patients with ECOG PS of 0 to 1
  • \[Cohort of pediatric malignant solid tumor Expansion part\]
• Patients aged ≥ 12 to \< 18 years at the time of signing the informed consent form (ICF)
• Patients with unresectable tumors for whom nivolumab intravenous monotherapy is indicated in adults according to the package insert
• Patients who have at least 1 measurable lesion per RECIST guideline
• Patients with ECOG PS of 0 to 2
  • \[Cohort of Epithelioid Sarcoma\]
• Patients aged ≥ 12 years of age at the time of signing the informed consent form (ICF). However, patients aged ≥ 12 to \< 18 years may be enrolled after tolerability is confirmed in the tolerability evaluation part in the cohort of pediatric malignant solid tumor.
• Patients who are refractory to or ineligible to at least 1 regimen of chemotherapy including doxorubicin for unresectable advanced or recurrent epithelioid sarcoma
• Patients who have at least 1 measurable lesion per RECIST guideline
• Patients with ECOG PS of 0 to 2
  • \[Common\]
• Life expectancy ≥ 3 months at the time of enrollment