A Study Evaluating AB248 Alone or in Combination with Pembrolizumab in Adult Patients with Solid Tumors

Inclusion Criteria:

• Age ≥18 years of age at the time consent is signed.

• Has adequate end organ function per laboratory testing.

• Pregnancy prevention requirements

• Has measurable disease per RECIST 1.1 as assessed by the local siteInvestigator/radiology.

• Has a performance status of 0 or 1 on Eastern Cooperative Oncology Group scale.

• Histologic documentation of incurable, locally advanced or metastatic tumor of thetype being evaluated in individual cohorts

Exclusion Criteria:

• Has a diagnosis of immunodeficiency.

• Has a history of a previous, additional malignancy, unless potentially curativetreatment has been completed, with no evidence of malignancy for 5 years.

• Has known active CNS metastases and/or carcinomatous meningitis.

• Has an active autoimmune disease that has required systemic treatment in the past 2years.

• Has an active infection requiring systemic therapy.

• Inability to comply with study and follow-up procedures.

• Has had a severe hypersensitivity reaction (Grade ≥3) to treatment withpembrolizumab, another monoclonal antibody, or has history of any hypersensitivityto any components of the study treatments or any of their excipients.

• Has received prior systemic anticancer therapy including investigational agentswithin 4 weeks (or, if shorter, within 5 half-lives for kinase inhibitors) prior tofirst dose of study treatment.

• Has received prior radiotherapy within 2 weeks of start of study treatment or hashad a history of radiation pneumonitis.

• Receiving chronic systemic steroid therapy or any other form of immunosuppressivetherapy within 7 days prior the first dose of study treatment.

• Has received previous treatment with another agent targeting the IL-2, IL-7, orIL-15 receptors.

• Is expected to require any other form of antineoplastic therapy while on study