This is a Phase 1a/b, first in human, open-label, dose escalation and expansion study in adults with advanced cancers. The study will comprise of~A Screening Period of up to 28 days~A Treatment Period during which participants will receive the study drug on the first day of each cycle where each cycle is 28 days. Number of cycles depends on how the disease responds to the study drug~A Follow-up Period which involves 1 visit for single agent and 2 visits for combination.
The purpose of this study is to test the safety and tolerability of HFB200301 as a single agent and in combination with tislelizumab in patients with advanced cancers. There are two parts in this study. During the escalation part, groups of participants will receive increasing doses of HFB200301 as a monotherapy or in combination with tislelizumab until a safe and tolerable dose of HFB200301 as a single agent or combination therapy is determined. During the expansion part, participants will take the dose of HFB200301 as a monotherapy or in combination with tislelizumab that was determined from the escalation part of the study and will be assigned to a group based on the type of cancer the participants have.