A Phase 1/2 Multicenter, Open-label, Dose-escalation, Safety, Pharmacodynamic, and Pharmacokinetic Study of Q901 Administered via Intravenous Infusion in Adult Patients with Selected Advanced Solid Tumors with a Cohort Expansion at the Recommended Phase 2 Dose

• Q901 is a small molecule inhibitor for CDK7 kinase activity, thereby inhibiting CDK7-mediated signaling. Inhibition of CDK7 may inhibit tumor cell proliferation via inhibiting cell cycle progression, such as CDK1, 2, 4 and 6.

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 alone or in combination with pembrolizumab
• The effects of the study drug (good and bad) alone or in combination with pembrolizumab
• much of the study drug / agent is absorbed into the blood and how fast it is removed
• How the study drug / agent is acting on your body
• The dose of the study drug that should be used in future studies

This is a dose escalation/expansion study. Dose Escalation means that the amount of the study given will be increased in each group of research participants to find the most appropriate dose for further study. This will be referred to as Part 1. In the dose expansion part of the study, a larger number of people receive the study drug dose determined to be appropriate in the dose escalation part of the study. Dose expansion will be referred to as Part 2. Those in Part 2 are separated into 2 groups, Group A and Group B. Group A will receive the study drug alone. Group B will receive the study drug in combination with pembrolizumab.

The part and dose of the study you receive will be determined by when you enroll into the study.

The study regimen will be given in cycles. For Part 1 and Part 2 Group A, each cycle will be 28 days. During the first cycle, you will receive the study once a week (on Days 1, 8, 15 and 22) as an infusion into your vein (IV infusion) over 30 minutes. During all subsequent cycles, you will receive the study drug once every 2 weeks (on Days 8 and 22 of each cycle) via IV infusion over 30 minutes.

For Part 2 Group B, each cycle will be 42 days. If you are in this group, you will receive pembrolizumab as an infusion into your vein (IV infusion) over 30 minutes on the first day of every cycle. During the first cycle, you will receive the study on Days 1, 8, 15, 22 and 36 as an infusion into your vein (IV infusion) over 30 minutes. During all subsequent cycles, you will receive the study drug on Days 8, 22 and 36 of each cycle via IV infusion over 30 minutes.

On the days in which you receive the study regimen, please expect to be in the clinic for about 6 hours. Some visits may take longer for additional blood testing.