First In Human Study of CX-2051 in Advanced Solid Tumors

Inclusion Criteria:

• Metastatic or locally advanced unresectable solid tumor that has progressed afterstandard therapy

• Eastern Cooperative Oncology Group (ECOG) performance status of 0-1

• Measurable disease per RECIST v1.1

• Consent to fresh biopsy or if medically contraindicated, recent (within 6 months)archival tumor tissue

• Additional inclusion criteria may apply

Exclusion Criteria:

• Recent history (within last 2 years) of localized cancers that are not related tothe current cancer being treated

• Known active central nervous system (CNS) involvement by malignancy

• Systemic anticancer treatment, radiotherapy, or investigational agent(s) within 14days prior to C1D1

• Previous treatment with antibody-drug conjugates (ADCs) with Topo-I inhibitorpayload

• Major surgery (requiring general anesthesia) within 4 weeks prior to C1D1

• Elevated baseline laboratory values

• Serious concurrent illness

• Pregnant or breast feeding

• Additional exclusion criteria may apply