What is the DeLLphi-304 study?

At your first study visit(s), you will:

• Meet the study doctor and study team at your study site, which may be different from where you have received treatment in the past
• Review and sign an informed consent with the study staff to join the DeLLphi-304 study
• Complete a general health assessment, including a physical exam, medical history, blood tests, and imaging
• Have your tumor sampled*

Each participant will be randomly assigned to receive either tarlatamab (study drug) or standard of care chemotherapy.

The tarlatamab group (~350 participants) will:

• Receive tarlatamab by infusion (in a vein) once a week for the first 3 weeks and then once every 2 weeks afterwards*
• Attend study appointments and check-ups to record your progress

* As a precaution, you will need to stay in the hospital for at least 48 hours after your first two tarlatamab treatments to monitor your health status. For later treatments, you may need to stay in the hospital if you have side effects from the medication.

The standard of care chemotherapy group (~350 participants) will:

• Receive either topotecan (Hycamtin®) by infusion or by mouth OR lurbinectedin (Zepzelca®) by infusion^
• Attend study appointments and check-ups to record your progress

You will continue to receive treatment in the study based on the results of your bloodwork and imaging. Your study treatment may stop if:

1. Your cancer gets worse*
2. You experience serious side-effects from treatment
3. You decide to stop the study at any time

The study team will schedule a follow-up visit with you approximately 6 weeks after your last study treatment.

The study team may follow-up with you by phone or ask you to visit the clinic approximately once every 3 months.