A Phase 1 Dose Escalation and Expansion Study of ABL503, a Bispecific Antibody of 4-1BB and PD-L1, as a Single Agent in Subjects With Any Progressive Locally Advanced (Unresectable) or Metastatic Solid Tumors

This is a first-in-human Phase 1, single-arm, open-label, multicenter, multiple-dose, dose-escalation and dose-expansion study of ABL503 to evaluate the safety, tolerability, MTD and/or RP2D, PK, immunogenicity, preliminary antitumor activity, and the PD effect of ABL503 in subjects with any progressive locally advanced (unresectable) or metastatic solid tumors who are relapsed or refractory following the last line of treatment and have no available standard of care option. This study includes 2 parts: a dose-escalation part and a dose-expansion part.