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

• CT7439 is a CDK12/13 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 much of the study drug is absorbed into the blood and how fast it is removed
• If research tests can be used in the future to predict who will benefit from (CT7439)

In Dose Escalation, groups of participants will receive different doses of the study drug to determine which dose is safe and tolerable.

The first group of participants will receive the lowest dose. If there are no harmful side effects seen, the next group of participants will receive a higher dose. Again, if it is decided that the next dose level is safe and tolerable, another group of participants will receive the next higher dose. This will continue until the highest dose is decided to be safe and tolerable without harmful side effects, or the highest planned dose is used. The dose you receive will depend on what dose is being tested when you start the study. Your dose may be reduced, or stopped if it is decided to be necessary for your health.

If you complete this part of the study and the study doctor thinks it would help your cancer, you may be able to keep taking the study drug in the Extension part of this study.