An Open-Label, Phase 1 Study to Evaluate Safety, Tolerability and Pharmacokinetics of the CTPS1 Inhibitor STP938 in Adult Subjects with Advanced Solid Tumors, with a Safety Expansion in Advanced CTPS2 Null Ovarian Cancer

• STP938 is a CTPS1 inhibitor

In this study, the sponsor and investigators want to learn:

• How much of the study drug can be given with an acceptable level of side effects
• The effects of the study drug (good and bad)
• How the study drug distributes in your body
• The effects of the drug on your cancer
• Monitor how your immune system and your cancer responds to the study drug

There are two parts in this study. Part 1 aims to determine a safe and tolerable dose of STP938 to be used in patients with cancer. Part 2 aims to further investigate the anti-tumor activity of a safe dose of STP938 established in Part 1.

The treatment in this study is given in repeating 28-day or 21-day periods called cycles. During each treatment cycle you will receive one or more capsules of STP938 to be taken twice a day without food. The very first time you receive STP938 will be in the clinic, and you will be given one dose of the drug, from Day 2 onwards you will take the drug twice a day.