A Modular, Multi-Part, Multi-Arm, Phase 1/2 Study to Evaluate the Safety and Tolerability of CT7439 Alone and in Combination with Anticancer Treatments in Participants with Solid Malignancies

• BBO-10203 modifies the catalytic α subunit of phosphoinositide 3-kinase (PI3Kα) thereby inhibiting its interaction with rat sarcoma vial oncogene homolog (RAS)

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

• How much of the study drug(s) can be given with an acceptable level of side effects
• The effects of the study drug(s) (good and bad)
• How much of the study drug(s) is absorbed into the blood and how fast it is removed
• How the study drug(s) is acting on your body

The study will consist of 2 parts – Dose Escalation and Dose Expansion. Your study doctor will inform you which part of the study you will be participating in.

Dose Escalation-Phase 1a:

• Monotherapy Dose Escalation/Cohort Expansion: Participants enrolled in this cohort will receive BBO-10203 (different dose levels will be evaluated) once daily as monotherapy.
• Combination Dose Escalation: Participants enrolled in this cohort will receive BBO-10203 (different dose levels) once daily in combination with Trastuzumab infusion (IV) or subcutaneous (SC)

Dose Expansion-Phase 1b:

• BBO-10203 Combination Dose Expansion: Participants enrolled in this cohort will receive BBO-10203 once daily in combination with Trastuzumab IV/SC