Solid Tumor (Excluding CNS)Phase 1IMPACTNCT07148050
Immunotherapy for Solid Tumor Malignancies in Pediatrics Using Interleukin-15 and -21 Armored Glypican-3-specific Chimeric Antigen Receptor T Cells
A Phase 1 study testing SC-CAR.GPC3xIL15.21 CAR T cells in people with Solid Tumor (Excluding CNS) and Liver Cell Carcinoma, run by Seattle Children's Hospital at 1 site in United States.
Trial summary
This Phase 1, open-label, non-randomized study will enroll pediatric and young adult subjects with relapsed or refractory non-central nervous system (CNS) malignant solid tumors expressing glypican-3 (GPC3) to examine the safety, feasibility, and efficacy of administering T cell products derived from peripheral blood… Read more about this study
- Who is it for?
- Ages 1 year to 26 years
- Conditions the study is for
- Solid Tumor (Excluding CNS), Liver Cell Carcinoma, Malignant Rhabdoid Tumor
- What is being tested?
- SC-CAR.GPC3xIL15.21 CAR T cells
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 21 participants
- Where
- 1 siteUnited States
- Study dates
- 22 Dec 2025to 22 Apr 2044
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 1 year to 26 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Diagnosis of a solid tumor expressing GPC3
- Lansky or Karnofsky score of >=60%
- Life expectancy of >16 weeks
- Informed consent explained to, understood by and signed by patient/guardian.
- For patients with hepatocellular carcinoma only:
- Barcelona Liver Cancer Stage A, B or C
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- Child-Pugh Turcotte Score <7
- Lansky or Karnofsky score of >=60%
- Life expectancy of >16 weeks
- Informed consent explained to, understood by and signed by patient/guardian.
- Adequate organ function
- Adequate laboratory values
- Refractory or relapsed disease after treatment with up- front therapy and at least one salvage treatment cycle
- Recovered from acute toxic effects of all prior chemotherapy and investigational agents before entering this study
- Sexually active patients must be willing to utilize one of the more effective birth control methods for 12 months after the T-cell infusion.
- Informed consent explained to, understood by and signed by patient/guardian.
- For patients with hepatocellular carcinoma only:
- Barcelona Liver Cancer Stage A, B or C
- Child-Pugh Turcotte Score <7
Who cannot join
- History of hypersensitivity reactions to murine protein-containing products OR presence of human anti-mouse antibody (HAMA) prior to enrollment for patients who have received prior therapy with murine antibodies.
- History of organ transplantation
- Known HIV positivity
- Active bacterial, fungal, or viral infection (except Hepatitis B or Hepatitis C virus infections)
- Treatment eligibility
- History of hypersensitivity reactions to murine protein-containing products OR presence of human anti-mouse antibody (HAMA) prior to enrollment for patients who have received prior therapy with murine antibodies.
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- History of organ transplantation
- Known HIV positivity
- Active autoimmune or inflammatory disorder
- Live vaccines within 30 days prior to enrollment
- Active bacterial, fungal, or viral infection (except Hepatitis B or Hepatitis C virus infections)
- Pregnancy or lactation
- Uncontrolled infection
- Systemic steroid treatment (≥ 0.5 mg prednisone equivalent/kg/day, dose adjustment or discontinuation of medication must occur at least 24hrs prior to CAR T cell infusion)
- Congestive heart failure (as defined by New York Heart Association Functional Classification III or IV), unstable angina, serious uncontrolled cardiac arrhythmia, a myocardial infarction within 6 months prior to study entry or a history of myocarditis.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Andras Heczey, MD contact
United States1 site, 1 recruiting
- Recruiting
Seattle Children's Hospital
Seattle, Washington, 98105
Michelle Choe, MD, 206-987-2106, michelle.choe@seattlechildrens.org
Andras Heczey, MD, andras.heczey@seattlechildrens.org
About this study
This Phase 1, open-label, non-randomized study will enroll pediatric and young adult subjects with relapsed or refractory non-central nervous system (CNS) malignant solid tumors expressing glypican-3 (GPC3) to examine the safety, feasibility, and efficacy of administering T cell products derived from peripheral blood mononuclear cells (PBMC) that have been genetically modified to co-express a GPC3-specific chimeric antigen receptor (CAR), interleukin (IL)-15 and IL-21 as well as the inducible caspase 9 (iC9) suicide gene (SC-CAR.GPC3xIL15.21 T cells).
A child or young adult meeting all eligibility criteria and meeting none of the exclusion criteria will have a blood sample collected, which will be used to bioengineer the CAR T cells targeting their tumor.
Read the detailed description
Study Overview
This study is testing a different treatment which uses the body's own immune system to recognize and kill the cancer cells, called chimeric antigen receptor (CAR) T cells. Some solid tumors express a specific type of molecule called glypican-3 or GPC3. We are able to insert a new gene (a piece of DNA that contains a set of instructions for the body) into T cells which are a type of immune system cell. This is how we make CAR T cells: We will insert a gene that will program the CAR T cell to recognize GPC3 to make GPC3-CAR T cells. To make GPC3-CAR T cells more effective against tumor cells, we also added two genes called IL15 and IL21 which help CAR T cells grow better and stay in the blood longer. We think that this will kill tumors better. When we did this in the laboratory, we found that this mixture of GPC3-CAR, IL15, and IL21 in T cells killed tumor cells better when compared with GPC3-CAR T cells that did not have IL15 and IL21. This research study will use these cells (named GPC3xIL15.21) to treat patients with solid tumors that express GPC3 on their surface. The GPC3xIL15.21 CAR T cells are an investigational product and have not been approved by the Food and Drug Administration.
We also wanted to make sure that we could stop the GPC3xIL15.21 CAR T cells from growing in the blood if there are any bad or severe side effects. To do so, we inserted a gene called iCasp9 into the GPC3xIL15.21 CAR T cells. This allows us to eliminate the GPC3xIL15.21 CAR T cells in the blood when we give a medicine called AP1903 (also known as rimiducid). Rimiducid is an experimental medicine that has been tested in humans, with no known bad side effects. We only intend to use this medicine to get rid of the GPC3xIL15.21 CAR T cells if you develop dangerous side effects. Approximately 21 people will participate in this study.
Treatment plan
We would first confirm that the participant tumor expresses GPC3. Upon confirmation, a maximum of approximately 6 tablespoons (or 90 mL) of blood will be drawn and sent to Seattle Children's Therapeutics (SCTx) to make the CAR T cells.
After the CAR T cells are made and treatment eligibility has been verified, participants will come to Seattle Children's Hospital for treatment and close monitoring for about one month. Participants will be given lymphodepleting chemotherapy for 3 days, using cyclophosphamide and fludarabine to make room for the CAR T cells, followed by CAR T cell infusion IV.
This is a dose escalation study, which means that the investigators do not know the highest safe dose of CAR T cells. The dose each patient gets depends on how many participants get the agent before that patient and how they react. Since the treatment is experimental, what is likely to happen at any dose is not known.
All of the treatments will be given at Seattle Children's Hospital.
After treatment, participants will be monitored closely for a month to monitor for side effects and response to treatment. After this month, participants would continue to be followed for 15 years after they receive your CAR T cells, with visits becoming less frequent the longer it has been since CAR T cell infusion.
- Conditions
- Solid Tumor (Excluding CNS), Liver Cell Carcinoma, Malignant Rhabdoid Tumor, Yolk Sac Tumor, Liposarcoma, Rhabdomyosarcoma
- Being tested
- SC-CAR.GPC3xIL15.21 CAR T cells
- Keywords
- CAR T cell, Pediatric, Young Adult, Non-CNS Tumor, Liver Cancer, Solid Tumor, GPC3, Glypican
- Medical subject headings
- Carcinoma, Hepatocellular, Rhabdoid Tumor, Endodermal Sinus Tumor, Liposarcoma, Rhabdomyosarcoma, Wilms Tumor, Hepatoblastoma, Liver Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SC-CAR.GPC3xIL15.21 CAR T cellsBiological
Autologous SC-CAR.GPC3xIL15.21 T cell products infusion
| Study group | Role | What they receive |
|---|---|---|
| SC-CAR.GPC3xIL15.21 T cells | Experimental | Autologous SC-CAR.GPC3xIL15.21 T cell product will be infused as a single infusion. Receives: Biological: SC-CAR.GPC3xIL15.21 CAR T cells |
What is being measured
The primary outcome is the main question the study is designed to answer.
The number of successfully manufactured SC-CAR.GPC3xIL15.21 T cell products will be assessed
The number of successfully manufactured products will be measured
Measured: 28 days
Establish the safety, defined by adverse events of SC-CAR.GPC3xIL15.21 T cells.
Type, frequency, severity, and duration of adverse events will be tabulated and summarized
Measured: 28 days
Secondary outcomes (2)
Estimate the maximum tolerated dose (MTD) or biologically effective dose and dose limiting toxicities (DLT), and describe the full toxicity profile of SC-CAR.GPC3xIL15.21 T cells.
Type, frequency, severity, and duration of adverse events will be tabulated and summarized
Measured: 28 days
To estimate anti-tumor responses by measuring changes in tumor burden using disease-specific evaluations following SC-CAR.GPC3xIL15.21 T cells.
Standard imaging and blood pathology will be used to determine disease response
Measured: 42 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Aug 2025
- Study start22 Dec 2025
- Primary completion22 Apr 2029 (estimated)
- Study completion22 Apr 2044 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Solid Tumor (Excluding CNS)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 21 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Seattle Children's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Colleen Annesley, Seattle Children's Hospital
- Investigators
- Colleen Annesley, MD, Study director, Seattle Children's HospitalCorinne Summers, MD, Study director, Seattle Children's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07148050
- Sponsor's protocol ID
- IMPACT
- Acronym
- IMPACT
- Status last verified
- Feb 2026
- First submitted
- 22 Aug 2025
- Last updated
- 17 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Immunotherapy for Solid Tumor Malignancies in Pediatrics Using Interleukin-15 and -21 Armored Glypican-3-specific Chimeric Antigen Receptor T Cells
- ClinicalTrials.gov ID
- NCT07148050
- Acronym / sponsor ID
- IMPACT / IMPACT
- Conditions
- Solid Tumor (Excluding CNS), Liver Cell Carcinoma, Malignant Rhabdoid Tumor, Yolk Sac Tumor, Liposarcoma, Rhabdomyosarcoma
- Keywords
- CAR T cell, Pediatric, Young Adult, Non-CNS Tumor, Liver Cancer, Solid Tumor, GPC3, Glypican
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 21 participants (estimated)
- Lead sponsor
- Seattle Children's HospitalUniversity, hospital or other
- Study start
- 22 Dec 2025 (actual)
- Primary completion
- 22 Apr 2029 (estimated)
- Study completion
- 22 Apr 2044 (estimated)
- First posted
- 29 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This Phase 1, open-label, non-randomized study will enroll pediatric and young adult subjects with relapsed or refractory non-central nervous system (CNS) malignant solid tumors expressing glypican-3 (GPC3) to examine the safety, feasibility, and efficacy of administering T cell products derived from peripheral blood mononuclear cells (PBMC) that have been genetically modified to co-express a GPC3-specific chimeric antigen receptor (CAR), interleukin (IL)-15 and IL-21 as well as the inducible caspase 9 (iC9) suicide gene (SC-CAR.GPC3xIL15.21 T cells).
A child or young adult meeting all eligibility criteria and meeting none of the exclusion criteria will have a blood sample collected, which will be used to bioengineer the CAR T cells targeting their tumor.
Detailed description
Study Overview
This study is testing a different treatment which uses the body's own immune system to recognize and kill the cancer cells, called chimeric antigen receptor (CAR) T cells. Some solid tumors express a specific type of molecule called glypican-3 or GPC3. We are able to insert a new gene (a piece of DNA that contains a set of instructions for the body) into T cells which are a type of immune system cell. This is how we make CAR T cells: We will insert a gene that will program the CAR T cell to recognize GPC3 to make GPC3-CAR T cells. To make GPC3-CAR T cells more effective against tumor cells, we also added two genes called IL15 and IL21 which help CAR T cells grow better and stay in the blood longer. We think that this will kill tumors better. When we did this in the laboratory, we found that this mixture of GPC3-CAR, IL15, and IL21 in T cells killed tumor cells better when compared with GPC3-CAR T cells that did not have IL15 and IL21. This research study will use these cells (named GPC3xIL15.21) to treat patients with solid tumors that express GPC3 on their surface. The GPC3xIL15.21 CAR T cells are an investigational product and have not been approved by the Food and Drug Administration.
We also wanted to make sure that we could stop the GPC3xIL15.21 CAR T cells from growing in the blood if there are any bad or severe side effects. To do so, we inserted a gene called iCasp9 into the GPC3xIL15.21 CAR T cells. This allows us to eliminate the GPC3xIL15.21 CAR T cells in the blood when we give a medicine called AP1903 (also known as rimiducid). Rimiducid is an experimental medicine that has been tested in humans, with no known bad side effects. We only intend to use this medicine to get rid of the GPC3xIL15.21 CAR T cells if you develop dangerous side effects. Approximately 21 people will participate in this study.
Treatment plan
We would first confirm that the participant tumor expresses GPC3. Upon confirmation, a maximum of approximately 6 tablespoons (or 90 mL) of blood will be drawn and sent to Seattle Children's Therapeutics (SCTx) to make the CAR T cells.
After the CAR T cells are made and treatment eligibility has been verified, participants will come to Seattle Children's Hospital for treatment and close monitoring for about one month. Participants will be given lymphodepleting chemotherapy for 3 days, using cyclophosphamide and fludarabine to make room for the CAR T cells, followed by CAR T cell infusion IV.
This is a dose escalation study, which means that the investigators do not know the highest safe dose of CAR T cells. The dose each patient gets depends on how many participants get the agent before that patient and how they react. Since the treatment is experimental, what is likely to happen at any dose is not known.
All of the treatments will be given at Seattle Children's Hospital.
After treatment, participants will be monitored closely for a month to monitor for side effects and response to treatment. After this month, participants would continue to be followed for 15 years after they receive your CAR T cells, with visits becoming less frequent the longer it has been since CAR T cell infusion.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| SC-CAR.GPC3xIL15.21 T cells | Experimental | Biological: SC-CAR.GPC3xIL15.21 CAR T cellsAutologous SC-CAR.GPC3xIL15.21 T cell product will be infused as a single infusion. |
Who may qualify
- Ages
- 1 year to 26 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (19 listed)
- Lansky or Karnofsky score of >=60%
- Life expectancy of >16 weeks
- Informed consent explained to, understood by and signed by patient/guardian.
- Adequate organ function
- Adequate laboratory values
Key exclusion criteria (15 listed)
- Treatment eligibility
- History of hypersensitivity reactions to murine protein-containing products OR presence of human anti-mouse antibody (HAMA) prior to enrollment for patients who have received prior therapy with murine antibodies.
- Active autoimmune or inflammatory disorder
- Live vaccines within 30 days prior to enrollment
- Pregnancy or lactation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SC-CAR.GPC3xIL15.21 CAR T cellsAutologous SC-CAR.GPC3xIL15.21 T cell products infusion | Biological | SC-CAR.GPC3xIL15.21 T cells |
Primary outcome
The number of successfully manufactured SC-CAR.GPC3xIL15.21 T cell products will be assessed
Time frame: 28 days
The number of successfully manufactured products will be measured
Establish the safety, defined by adverse events of SC-CAR.GPC3xIL15.21 T cells.
Time frame: 28 days
Type, frequency, severity, and duration of adverse events will be tabulated and summarized
2 secondary outcomes
Estimate the maximum tolerated dose (MTD) or biologically effective dose and dose limiting toxicities (DLT), and describe the full toxicity profile of SC-CAR.GPC3xIL15.21 T cells.
Time frame: 28 days
To estimate anti-tumor responses by measuring changes in tumor burden using disease-specific evaluations following SC-CAR.GPC3xIL15.21 T cells.
Time frame: 42 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Feb 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Andras Heczey, MD contact
Colleen Annesley, MD study director
Seattle Children's Hospital
Corinne Summers, MD study director
Seattle Children's Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing SC-CAR.GPC3xIL15.21 CAR T cells in people with Solid Tumor (Excluding CNS) and Liver Cell Carcinoma, run by Seattle Children's Hospital at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 19 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 17 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Michelle Choe, MD (206-987-2106, immunotherapy@seattlechildrens.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The number of successfully manufactured SC-CAR.GPC3xIL15.21 T cell products will be assessed (time frame: 28 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Feb 2026.