CAR T-Cell Immunotherapy Clinical Trials for Solid Tumors

Seattle Children’s doctors and researchers are leaders in developing investigational chimeric antigen receptor (CAR) T-cell immunotherapies for children and young adults with relapsed or refractory solid tumors.

T-cell immunotherapy is an experimental cancer treatment that stimulates the immune system to fight disease.

Read more about how T-cell immunotherapy for solid tumors works.

Food and Drug Administration-authorized trials at Seattle Children’s are testing T-cell therapy in children and young adults with relapsed or refractory solid tumors who are not likely to survive with current treatments.

Current phase 1 trials open to accrual at Seattle Children's are:

• IMPACT
• FIERCe

How is CAR T-cell therapy used for patients with solid tumors?

In the IMPACT trial, the patient’s own T cells are reprogrammed to recognize and target a protein expressed by tumor cells called, glypican-3 or GPC3. Examples of tumor types that express GPC3 include hepatoblastoma, hepatocellular carcinoma, yolk sac tumor, rhabdomyosarcoma and rhabdoid tumor. IMPACT is studying GPC3-targeting CAR T cells armored with IL15 and IL21, proteins that help CAR T cells grow and work better. This therapy was developed by Dr. Andras Heczey and the Heczey Lab, now at Seattle Children’s Research Institute.

In the FIERCe trial, the patient’s own T cells are reprogrammed to recognize and target a protein that can be expressed by osteosarcoma, called folate receptor alpha or FOLR1. FOLR1-CAR T cells were developed in the Meshinchi Lab at Fred Hutch Cancer Center. This trial is currently enrolling patients with relapsed or refractory osteosarcoma.

• Read more about IMPACT and FIERCe at clinicaltrials.gov.
• Learn more about this and other clinical trials at Seattle Children’s.
• For more information, call 206-987-2106 or send us an email at [email protected].

What is the goal of these solid tumor CAR T-cell studies? 

Currently all of our CAR T-cell clinical trials for solid tumors are phase 1 clinical trials. Phase 1 trials focus on finding out how much of a therapy to give, how to give it, how often to give it and what side effects occur. For each trial, researchers are working to answer these questions:

• Is T-cell therapy safe to give to children, teens and young adults with relapsed or refractory solid tumors?
• What is the best dose of CAR T cells for children, teens and young adults with solid tumors?
• Does T-cell therapy work against solid tumors?

Who can join these solid tumor CAR T-cell studies? 

The IMPACT trial is for children, teens and young adults who:

• Have relapsed or refractory solid tumors that expresses GPC3
• Are ages 1 to 26 years old

The FIERCe trial is for children, teens, adults who:

• Have relapsed or refractory osteosarcoma
• Are ages 1 to 75 years old

Researchers use many other factors to decide whether a patient can take part in a study (inclusion criteria) or cannot take part (exclusion criteria). The study team at Seattle Children’s can explain what these factors mean for you or your child.

Who is leading these solid tumor T-cell clinical trials? 

Our clinical investigators include:

• Dr. Catherine (Katie) Albert, a doctor in the Cancer and Blood Disorders Center at Seattle Children’s Hospital and an investigator in the Ben Towne Center for Childhood Cancer and Blood Disorders Research at Seattle Children’s Research Institute. Dr. Albert is the PI for STRIVe and co-PI for FIERCe.
• Dr. Michelle Choe, a doctor in the Cancer and Blood Disorders Center at Seattle Children’s Hospital and an investigator in the Fred Hutch Cancer Center. Dr. Choe is the PI for IMPACT and co-PI for FIERCe.
• Dr. Mallory (Molly) Taylor, a doctor in the Cancer and Blood Disorders Center at Seattle Children’s Hospital and an investigator in the Ben Towne Center for Childhood Cancer and Blood Disorders Research at Seattle Children’s Research Institute.

Are there CAR T-cell clinical trials for other childhood cancers?

IMPACT and FIERCe are two of our many T-cell immunotherapy trials focused on using the immune system to offer better treatment options for children, teens and young adults with cancers, including:

• Solid tumors (STRIVe)
• Leukemia and lymphoma (PLAT)
• Brain and central nervous system tumors (BrainChild)

Contact Us

For more information, call 206-987-2106 or send us an email at [email protected].  

Learn More 

• Learn more about our Bone Tumors and Soft-Tissue Tumors program.
• Find other cancer clinical trials at Seattle Children’s:
  • On our Research Studies page.
  • On ClinicalTrials.gov. Read our guide about searching for trials on ClinicalTrials.gov (PDF).
• Learn about Seattle Children's Therapeutics. 

Updated March 2026.