Clinical Trial Summary (S2409)

Using Biomarker Tests to Select and Test New, Personalized Treatments for Extensive Stage Small Cell Lung Cancer (PRISM Trial)

What is the purpose of this clinical trial?

This trial is testing personalized treatment options for people with extensive stage small cell lung cancer (ES-SCLC). ES-SCLC is small cell lung cancer that has spread to the other lung or other parts of the body.

There are different subtypes (or kinds) of ES-SCLC — and certain drugs may work better for certain subtypes. In this study, researchers will test the cancer for specific features (called biomarkers) to figure out which ES-SCLC subtype people have.

The goal is to match each subtype with the best maintenance treatment. Maintenance treatment is given after the initial (first) treatment patients get.

This trial is set up to find out:

If testing ES-SCLC for certain biomarkers can help match people with treatments that work better for them
If combining certain drugs with the standard treatment (durvalumab) can help keep ES-SCLC from growing or spreading
What side effects the study treatments might cause

Why is this trial important?

The standard treatment for ES-SCLC doesn’t work well for many people. But testing for biomarkers to figure out which ES-SCLC subtype people have might help doctors personalize treatments. That means this trial could lead to new and better treatment options that help more patients in the future.

This trial may be for people who:

Have extensive stage small cell lung cancer
Haven’t started initial treatment or have received up to 3 cycles of initial treatment
Are age 18 or older

This trial is not for people who:

Already finished initial treatment for extensive stage small cell lung cancer
Have had limited stage small cell lung cancer
Have had an organ transplant
Are pregnant or breastfeeding

What treatments will I get?

Step 1: Initial treatment

If you haven’t started initial treatment yet, you’ll start getting the standard treatment as soon as possible. This includes chemotherapy drugs (cisplatin or carboplatin, plus etoposide) and an immunotherapy drug (durvalumab).

Biomarker testing

During Step 1 of the study, your care team will send a sample of your tumor to a lab for biomarker testing. If possible, they’ll use a sample that was removed in a past surgery or biopsy.

The biomarker testing will show if the cancer is:

Subtype
P

Subtype
A

Subtype
N

Subtype
I

or
None of these subtypes

If the cancer is one of these subtypes, you can receive maintenance treatment in the study after you finish initial treatment. (See Step 2 on page 3.)

If the cancer is not one of these subtypes, your part in the study will be over. Your doctor will talk with you about other treatment options that may be right for you.

The testing will also show if the cancer is:

SLFN11 positive — meaning it has a protein called SLFN11
SLFN11 negative — meaning it doesn’t have the SLFN11 protein

Knowing if the cancer is SLFN11 positive or SLFN11 negative will help your care team decide which maintenance treatment you’ll get.

Step 2: Maintenance treatment

A computer will randomly assign you to one of the study groups below. Your doctor won’t have control over which group you’re assigned to. This helps make sure the study results are fair and reliable.

Group 1:
Usual Treatment

durvalumab

Group 2:
Study Treatment

durvalumab
+
the drug being tested for the cancer subtype you have

You’ll get durvalumab through an IV (a needle placed into a vein in your arm). You’ll get the drug once every 28 days.

The chart below shows which drug will be given to people with each subtype — as well as when and how you’ll get each drug.

Tumor subtype	Drug
Subtype P Subtype A and SLFN11 positive Subtype N and SLFN11 positive	saruparib Saruparib is a pill You’ll take the drug once a day
Subtype A and SLFN11 negative Subtype N and SLFN11 negative	ceralasertib Ceralasertib is a pill You’ll take the drug in cycles, and each cycle lasts 28 days You’ll take the drug twice a day on the first 7 days of every cycle
Subtype I	monalizumab You’ll get monalizumab through an IV (a needle placed into a vein in your arm) You’ll get the drug in cycles, and each cycle lasts 28 days You’ll get the drug on Day 1 and Day 15 of each cycle

How long will I be in the trial?

You’ll be in the study for up to 3 years from the time you join Step 2 (maintenance treatment).

You can choose to stop treatment at any time, for any reason. Even if you stop treatment, you’ll have visits with your doctor every 2 or 3 months so they can see how you’re doing.

Are there costs? Will I get paid?

Biomarker testing, durvalumab, saruparib, ceralasertib, and monalizumab are provided at no cost to people in the study.

To learn more about what costs will and won’t be covered, talk to your health care provider and insurance provider.

You will not be paid for joining the study.

Where can I find more information about this trial?

Talk with your health care provider
Call the National Cancer Institute at 1-800-4-CANCER
Go to www.ClinicalTrials.gov and search the national clinical trial number: NCT06769126
For a list of trial locations, visit swog.org/NCI-S2409

Key Information

Information your doctor or trial navigator may need to help you.

Protocol Number

S2409

NCT Number

NCT06769126

Full Trial Title

PRISM: Precision in SCLC via a Multicohort Study: Randomized Phase II Studies Evaluating Maintenance Durvalumab with or without Biomarker-Directed Therapy for Extensive Stage Small Cell Lung Cancer (ES-SCLC)

Trial Sponsors

SWOG Cancer Research Network

Publication Date

September 5, 2025