A First-in-Human Study of BG-C0979 in Adults With Advanced Solid Tumors

The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics (PK), and preliminary antitumor activity of BG-C0979 monotherapy or in combination with tislelizumab in participants with selected advanced solid tumors. The study will consist of Phase 1a (Dose Escalation and Safety Expansion) and Phase 1b (Dose Expansion).

Inclusion Criteria: * Phase 1a (Monotherapy Dose Escalation and Safety Expansion): Participants with histologically or cytologically confirmed advanced, metastatic, and unresectable solid tumors who have previously received standard systemic therapy or for whom treatment is not available or not tolerated, or determined not appropriate based on investigator's judgment. * Phase 1b Part A (Monotherapy Dose Optimization and Expansion): Participants with histologically or cytologically confirmed advanced, metastatic, and unresectable solid tumors who have previously received standard systemic therapy or for whom treatment is not available or not tolerated, or determined not appropriate based on investigator's judgment. * Phase 1b Part B (Combination Therapy Expansion): Participants with histologically or cytologically confirmed metastatic or unresectable advanced solid tumors who have not received any prior systemic treatment for advanced or metastatic disease. * Participants must have ≥ 1 measurable lesion as assessed by RECIST v1.1. * Participants must have a stable Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1. * Participants must have adequate organ function. Exclusion Criteria: * Prior treatment with any ADAM9 (a disintegrin and metalloproteinase domain 9)-targeted antibody-drug conjugates (ADCs) or ADCs containing TOPO1 (DNA topoisomerase 1) inhibitor as payload. * Active leptomeningeal disease or uncontrolled, untreated brain metastasis. Note: Other protocol defined Inclusion/Exclusion criteria may apply.