IL-18 Armored STEAP1 CAR T Cells for the Treatment of Metastatic Castration Resistant Prostate Cancer
Phase 1 Dose-Escalation and Expansion Study of IL-18 Armored STEAP1 CAR T in Participants With mCRPC
3 other identifiers
interventional
20
1 country
1
Brief Summary
This phase I trial tests the safety, side effects, best dose and how well giving IL-18 armored STEAP1 CAR T cells after lymphodepleting chemotherapy (with cyclophosphamide and fludarabine) works for the treatment of castration resistant prostate cancer that has spread from where it first started (primary site) to other places in the body (metastatic). Giving chemotherapy, with cyclophosphamide and fludarabine, prior to CAR T cells helps kill cancer cells in the body and prepare the body to receive the CAR T cells. Chimeric antigen receptor (CAR) T-cell therapy is a type of treatment in which a patient's T cells (a type of immune system cell) are changed in the laboratory so they will attack cancer cells. T cells are taken from a patient's blood. Then the gene for a special receptor that binds to a certain protein on the patient's cancer cells is added to the T cells in the laboratory. The special receptor is called a chimeric antigen receptor. Large numbers of the CAR T cells are grown in the laboratory and given to the patient by infusion for treatment of certain cancers. Giving IL-18 armored STEAP1 CAR T cells after lymphodepleting chemotherapy may be safe, tolerable and/or effective in treating patients with metastatic castration resistant prostate cancer.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for phase_1
Started Oct 2026
Longer than P75 for phase_1
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
August 28, 2026
CompletedFirst Posted
Study publicly available on registry
September 4, 2026
CompletedStudy Start
First participant enrolled
October 31, 2026
ExpectedPrimary Completion
Last participant's last visit for primary outcome
October 31, 2030
Study Completion
Last participant's last visit for all outcomes
October 31, 2044
September 4, 2026
August 1, 2026
4 years
August 28, 2026
August 28, 2026
Conditions
Outcome Measures
Primary Outcomes (3)
Treatment-related unexpected grade 3 or higher toxicity
Up to 28 days post infusion
Incidence of adverse events
Up to 28 days post infusion
Prostate cancer response
Assessed by Prostate Cancer Working Group 3 (PCWG3) criteria.
Up to 1 year post infusion
Secondary Outcomes (7)
Progression free survival
From initiation of protocol treatment to disease progression or death of any cause, up to 1 year post infusion
Overall survival
From initiation of protocol treatment to death of any cause, up to 1 year post infusion
Objective response rate
Up to 1 year post infusion
Stable disease
Up to 1 year post infusion
Clinical benefit
Up to 1 year post infusion
- +2 more secondary outcomes
Study Arms (1)
Treatment (chemotherapy, FH-STEAP1 IL-18 CAR T cells)
EXPERIMENTALPatients undergo leukapheresis. Patients receive cyclophosphamide intravenously (IV) and fludarabine IV on days -5 to -3. Patients receive FH-STEAP1 IL-18 CAR T cell IV on day 0. Patients may continue to receive androgen deprivation therapy per standard of care, throughout the study. Patients undergo nuclear medicine bone scan, CT scan, MRI and/or PET scan, tumor biopsy and blood sample collection throughout the study. Patients may also undergo MUGA scan or echocardiography during screening.
Interventions
Receive standard of care androgen deprivation therapy
Undergo nuclear medicine bone scan
Undergo echocardiography
Undergo tumor biopsy
Undergo blood sample collection
Undergo CT scan
Given IV
Given IV
Undergo leukapheresis
Undergo MRI
Undergo MUGA scan
Undergo PET scan
Given FH-STEAP1 IL-18 CAR T cells IV
Eligibility Criteria
You may qualify if:
- Documented, histologically confirmed adenocarcinoma of the prostate
- Measurable disease by RECIST 1.1 criteria or bone only metastases with measurable PSA (≥ 1ng/mL)
- Must have mCRPC with progressive disease (PD), stable disease (SD), lack of clinical benefit or intolerance to ≥ 1 line of systemic therapy, after becoming castration resistant
- Have received the following for metastatic prostate cancer:
- At least two lines of Food and Drug Administration (FDA)-approved therapies with at least one being a second-generation androgen receptor signaling inhibitor.
- Targeted therapies for which they are eligible in the metastatic setting unless the patient has contraindications to receiving those medications, the agents are not available to the patient or the patient declines to receive these drugs due to personal preference
- Castrate levels of testosterone (\< 50 ng/dL) with or without the use of androgen deprivation therapy
- years or older at the time of enrollment
- Capable of understanding and providing written informed consent
- Fertile male participants and their female partners must be willing to use an effective contraceptive method before, during, and for at least 4 months after the FH-STEAP1 IL-18 CAR T cell infusion
- Participants will be permitted to receive radiation therapy for palliative purposes throughout the study period, except during the 2-week period prior to undergoing leukapheresis
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Serum creatinine ≤ 1.5 x upper limit of normal (ULN) or estimated creatinine clearance \> 50 mL/min as calculated using the Cockcroft-Gault formula and not dialysis dependent
- Total bilirubin ≤ 1.5 x ULN. Participants with suspected Gilbert syndrome may be included if total bilirubin (bili) \> 3 mg/dL but no other evidence of hepatic dysfunction
- Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \< 5 x ULN
- +5 more criteria
You may not qualify if:
- Expecting to conceive or father children for the duration of the trial through 4 months after T cell infusion
- Patients that require immediate therapy due to mass effect or spinal cord compression
- Active autoimmune disease: Participants with active autoimmune disease requiring chronic immunosuppressive therapy are excluded. Case by case exemptions are possible with approval by principal investigator (PI)
- Corticosteroid therapy at a dose equivalent of \> 10 mg of prednisone per day (or equivalent). Pulsed corticosteroid use for disease control is acceptable
- Concurrent use of other investigational anti-cancer agents except for androgen deprivation therapy
- Uncontrolled concurrent illness: Participants may not have uncontrolled respiratory, endocrine, renal, gastrointestinal, genitourinary or systemic infection. There are exceptions to this criterion:
- HIV positive participants on highly active antiretroviral therapy (HAART) with a CD4 count \> 500 cells/mm\^3 are considered controlled, as are individuals with a history of hepatitis C who have successfully completed antiviral therapy with an undetectable viral load, and those with hepatitis B who have hepatitis well controlled on medication;
- Patients who have recent history of cerebrovascular accident, transient ischemic attack should be cleared by the neurology service before enrolling this study
- Patients who have recent history of coronary artery disease or cardiac arrhythmia should be cleared by the cardiology service before enrolling this study. Case by case exemptions are possible with approval by PI
- Participants with brain metastasis
- Active treatment for prior immune related adverse event to any immunotherapy: Participants receiving ongoing treatment for prior serious immune-related adverse events are excluded, with exception of hormone supplementation or corticosteroid therapy at equivalent of \> 10 mg prednisone (or equivalent) per day, unless otherwise approved by PI
- Patients with a second malignancy in addition to their prostate cancer are not eligible if the second malignancy has required systemic treatment within the past 4 years or is not in complete remission. There are exceptions to this criterion: successfully treated non-metastatic basal cell and squamous cell skin carcinoma
- Other medical, social, or psychiatric factor that interferes with medical appropriateness and/or ability to comply with study, as determined by the PI
- Known allergic reactions to any of the components of study treatments
- Participants who do not have a reasonable standard-of-care bridging therapy option available, as determined by the treating medical oncologist, to maintain disease control should clinically significant disease progression or worsening symptoms occur during the screening and T-cell manufacturing period
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Fred Hutchinson Cancer Centerlead
- PromiCell Therapeutics, Inc.collaborator
Study Sites (1)
Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, 98109, United States
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Rosa Nadal Rios, MD, PhD
Fred Hutch/University of Washington Cancer Consortium
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 1
- Allocation
- NA
- Masking
- NONE
- Purpose
- TREATMENT
- Intervention Model
- SINGLE GROUP
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
August 28, 2026
First Posted
September 4, 2026
Study Start (Estimated)
October 31, 2026
Primary Completion (Estimated)
October 31, 2030
Study Completion (Estimated)
October 31, 2044
Last Updated
September 4, 2026
Record last verified: 2026-08
Data Sharing
- IPD Sharing
- Will not share