A Study to Evaluate Safety, Efficacy, and Pharmacokinetics in Participants With Advanced Solid Tumors

Key Inclusion Criteria:

• Histologically or cytologically confirmed diagnosis of metastatic or locally advancedsolid tumors for which no standard therapy exists or standard therapy has failedbecause of disease progression or unacceptable toxicities. Also includes patients whocannot be treated with standard therapy because of underlying/existing medicalcondition.
• Cohort 1 (colorectal cancer): a) CRC (including microsatellite instability-high [MSI-H] and microsatellite-stable [MSS]) regardless of RAS mutation. b) Diseaseprogression within 3 months after last administration of approved standard therapies.c) Prior cytotoxic chemotherapy for metastatic disease include all the followingagents: fluoropyrimidine, oxaliplatin, and irinotecan
• Adjuvant chemotherapy-based treatments count as prior therapy, as long as relapse hadoccurred within 6 months of completion of such therapies, prior anti-epidermal growthfactor receptor (EGFR) therapy (cetuximab, panitumumab), anti-angiogenic therapy (bevacizumab, aflibercept, ramucirumab), regorafenib, and TAS-102 are allowed. d) Nomore than 5 prior therapies for metastatic disease. For participants who had diseaserecurrence within 6 months of completing adjuvant chemotherapy, the adjuvant regimencan be considered as 1 chemotherapy regimen for metastatic disease
• Cohort 2 (NSCLC): a) NSCLC without known EGFR, anaplastic lymphoma kinase (ALK), andROS1 genomic tumor aberrations. b) No standard therapy exists or standard therapy hasfailed. c) No more than 3 prior therapies for metastatic disease
• Phase 2: At least 1 measurable lesion per RECIST version 1.1
• Eastern Cooperative Oncology Group (ECOG) performance score of 0 to 2
• Adequate organ and bone marrow function (Hemoglobin >9.0 g/dL, Absolute neutrophilcount ≥1,500/μL, Absolute lymphocyte count ≥600 and ≤2,500/μL, Platelet count ≥100,000/μL, Total bilirubin ≤1.5 × upper limit of normal, Alanine aminotransferaseand aspartate aminotransferase ≤2.5 × ULN, Serum creatinine ≤1.5 × ULN or creatinineclearance >30 mL/min, Prothrombin time and activated partial thromboplastin time ≤1.5 × ULN)
• Life expectancy of at least 12 weeks
• Voluntarily provided a written consent to participate in the study
• Women of childbearing potential (WOCBP) must have a negative serum pregnancy testwithin the 7 days before study drug administration
• WOCBP and sexually active fertile male patients with partners who are WOCBP must agreeto use 2 highly effective methods of contraception throughout the course of the studyand for 12 weeks after the last dose of study drug.

Key Exclusion Criteria:

• Primary central nervous system (CNS) tumor (Phase 1), CNS metastasis, and/orcarcinomatous meningitis. Participants with prior brain metastases treated at least 4weeks before the first dose of EU101 that are clinically stable and do not requirechronic corticosteroid treatment are allowed. Untreated but asymptomatic andclinically stable brain metastases per investigator's discretion are allowed
• Received prior therapy with any anti-CD137 monoclonal antibody (mAb) or agent
• Major surgery requiring general anesthesia within 3 weeks before first dose of EU101or still recovering from prior surgery
• Active infection that is not controlled or requires intravenous antibiotics in thelast 2 weeks
• History of allogeneic tissue or organ transplant
• Active hepatitis B virus or hepatitis C virus infection
• History of any noninfectious hepatitis
• Human immunodeficiency virus (HIV) infection
• Received or receiving systemic corticosteroid therapy or any other form of systemicimmunosuppressive medicaion 1 week before first dose of EU101
• Known severe (≥Grade 3) hypersensitivity reactions to antibody, or severe reaction toimmuno-oncology agents requiring treatment with steroids
• Konwn or suspected hypersensitivity to EU101 or any component of its formulation
• Current or history of interstitial lung disease, anaphylaxis, uncontrolled asthma, orpneumonitis that has required systemic corticosteroids
• Patients with second primary cancer
• Clinically significant concurrent cardiovascular disease
• Pregnant women, breasfeeding women, WOCBP, or men with partners who are WOCBP who donot agree to use adequate contraceptive measures
• Determined as unable to participate in the study per investigator's judgment Other protocol defined Inclusion/Exclusion criteria may apply