A Study to Investigate the Safety, Pharmacokinetics, and Clinical Activity of AP203 in Patients with Locally Advanced or Metastatic Solid Tumors, and Expansion to Selected Malignancies

"Eight dose levels ranging from 0.00064 to 20 mg/kg will be evaluated to determine the maximum tolerated dose (MTD) or the maximum administered dose (MAD) or the recommended phase 2 dose(s) (RP2D\[s\]).~Participants will be administered by intravenous (IV) infusion, every week (Q1W \[± 1days\]) for the first 3 weeks (from the first to the fourth dose), then administered every 2 weeks (Q2W \[± 3 days\]) for all the following doses."

The dose-expansion phase will be conducted following completion of dose escalation for AP203. Participants will receive AP203 by IV infusion, administered Q1W (± 1 days) for the first 3 weeks (from the first to the fourth dose), then administered Q2W (± 3 days) for all the following doses, at the RP2D for each expansion cohort.