The sponsor has decided to adjust the development strategy of the investigational drug in this study.

This is a First-in-Human Phase I trial of ATG-101 in Patients with Metastatic/Advanced Solid Tumors and Mature B-cell Non-Hodgkin Lymphomas.

This is a First-in-Human Phase I trial of ATG-101 in Patients with Metastatic/Advanced Solid Tumors and Mature B-cell Non-Hodgkin Lymphomas. Dose Escalation Phase: Approximately 40-50 subjects with a maximum number of 62; 1-20 subjects for enhanced PDx cohort. Dose Expansion Phase: Estimated between 2 and 5 cohorts, each of approximately 40-50 patients to be expanded.

Inclusion Criteria:

1. Provision of signed and dated, written informed consent prior to any study-specific procedures, sampling, and analyses.
2. Aged 18 to 75 years as of the date of consent.
3. Histological or cytological confirmation of a solid tumor, and has relapsed or refractory from standard therapies.
4. Subjects with solid tumors have at least 1 measurable lesion per RECIST v1.1.
5. Estimated life expectancy of a minimum of 12 weeks.
6. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 at ICF signature.

Exclusion Criteria:

1. Subjects with CNS tumors or known CNS metastases will be excluded from the Dose Escalation Phase.
2. Prior treatment with a 4-1BB agonist.
3. Subjects with primary liver cancer.
4. Known history of human immunodeficiency virus infection.
5. History of hypersensitivity or history of allergic reactions attributed to drugs with a similar chemical or biologic structure or class to ATG-101.
6. Pregnant or nursing females.