RecruitingNCT06236139Updated Aug 11, 2026

Cell Therapy (STEAP1 CART) With Enzalutamide for the Treatment of Patients With Metastatic Castration-Resistant Prostate Cancer

A Phase 1/2 interventional study of Anti-STEAP1 CAR T-cells and Biopsy Procedure in Metastatic Castration-Resistant Prostate Carcinoma, Metastatic Prostate Adenocarcinoma and Stage IVB Prostate Cancer AJCC v8, sponsored by Fred Hutchinson Cancer Center. Recruiting at 1 site in United States. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-11.

Sponsored by Fred Hutchinson Cancer Center · Phase 1/2, Interventional, and Treatment

From the registry’s dates

Started Nov 2024; still recruiting 1 year 10 months later.

Phase: Phase 1/2
Study type: Interventional
Enrollment: 48
Allocation: Not applicable
Ages: 18 Years and older
Sex: Male

Study summary

This phase I/II trial tests the safety and effectiveness of cell therapy (STEAP1 CART) with enzalutamide in treating patients with prostate cancer that continues to grow despite surgical or medical treatments to block androgen production (castration-resistant) and that has spread from where it first started (the prostate) to other places in the body (metastatic). Prostate cancer is the second leading cause of cancer deaths in men. Localized prostate cancer is often curable and even metastatic disease may respond to treatment for a few years. Despite multiple therapies, including hormone therapy and chemotherapy, metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease. Recently, adoptive cellular immunotherapies have been developed to transfer immunogenic cells to the patient to produce an anti-tumor response. Chimeric antigen receptor T (CART)-cell therapy is a type of treatment in which a patient's T-cells (a type of immune cell) are changed in the laboratory so they will attack tumor 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 tumor cells is added to the T cells in the laboratory. The special receptor is called a chimeric antigen receptor (CAR). Large numbers of the CAR T cells are grown in the laboratory and given to the patient by infusion for treatment of certain cancers. Prostate stem cell antigen and prostate specific membrane antigen CAR T cell therapies have been shown to be safe and effective, but objective tumor responses remain rare. STEAP1 is an antigen that promotes cancer growth and spread and is found to be broadly expressed in mCRPC tissues. STEAP1 CART is CAR T cells that have been engineered with a STEAP1 antigen to better target prostate tumor cells. Enzalutamide is in a class of medications called androgen receptor inhibitors. It works by blocking the effects of androgen (a male reproductive hormone) to stop the growth and spread of cancer cells. Giving STEAP1 CART with enzalutamide may kill more tumor cells in patients with mCRPC.

Read the detailed description

OUTLINE: This is a dose escalation study of STEAP1 CART in combination with enzalutamide followed by a dose expansion study.

Patients undergo leukapheresis then receive cyclophosphamide intravenously (IV) and fludarabine IV on days -5, -4 and -3 and STEAP1 CART IV on day 0. Patients may receive enzalutamide orally (PO) on day 0 then once daily (QD) in the absence of disease progression or unacceptable toxicity. Patients also undergo a tumor biopsy at baseline, day 14 and optionally at progression. Patients additionally undergo blood sample collection, nuclear medicine (NM) bone scan and computed tomography (CT) scan, or magnetic resonance imaging (MRI) or positron emission tomography (PET) scan throughout study. Additionally, patients may undergo echocardiography (ECHO) or multigated acquisition scan (MUGA) at screening.

After completion of study treatment, patients are followed up at 2, 3, 4, 5, 6, 9, and 12 months then every 6 months up to year 5 followed by yearly up to year 15.

Conditions studied

Metastatic Castration-Resistant Prostate Carcinoma
Metastatic Prostate Adenocarcinoma
Stage IVB Prostate Cancer AJCC v8

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Prostatic Neoplasms 6,370

In context

Prostatic Neoplasms

6,370 studies on the registry are indexed under Prostatic Neoplasms; 1,400 are open to participants now.

This study's planned enrollment of 48 is below the median of 58 across 4,822 interventional studies indexed under Prostatic Neoplasms.

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Lead sponsor

Fred Hutchinson Cancer Center is the lead sponsor of 537 studies on the registry; 79 are open to participants now.

Of its 57 completed or terminated interventional studies of FDA-regulated products, 45 (79%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years and older
Sexes eligible: Male
Accepts healthy volunteers: No

Inclusion criteria

Tissue confirmation of prostate adenocarcinoma
Measurable disease by RECIST 1.1 criteria or bone only metastases with measurable PSA ( ≥ 1 ng/mL)
Must have progressed (at least 2 rising PSA levels with at least a 1-week interval and a minimum PSA of 1.0 ng/mL, progression per RECIST 1.1, or 2 or more new bone lesions by bone scan), after becoming castration-resistant
Have received the following for metastatic prostate cancer:
- At least two lines of treatment
- At least two Food and Drug Administration (FDA)-approved therapies with at least one being a second generation androgen receptor signaling inhibitor (e.g., abiraterone, darolutamide, apalutamide, or enzalutamide)
- All available targeted therapies for which they are eligible in the metastatic setting (e.g., PARP inhibitors for BRCA 1/2 and immune checkpoint inhibitor for MSI-H or TMB-H ≥ 10 mut/Mb)
Castrate levels of testosterone (\< 50 ng/dL) with or without the use of androgen deprivation therapy (ADT)
18 years or older at the time of enrollment
Capable of understanding and providing a 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 STEAP1 CART cell infusion
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
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
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
≤ grade 1 dyspnea and oxygen saturation (SaO2) ≥ 92% on ambient air
If pulmonary function tests (PFTs) are performed based on the clinical judgement of the treating physician, participants with forced expiratory volume in 1 second (FEVI) >= 50% of predicted and diffusion capacity of the lung for carbon monoxide (DLCO) (corrected) of >= 40% of predicted will be eligible
Participants >= 60 years of age are required to have left ventricular ejection fraction (LVEF) evaluation performed within 1 year prior to lymphodepletion chemotherapy. LVEF may be established with echocardiogram or MUGA scan, and left ejection fraction must be >= 35%. Cardiac evaluation for other participants is at the discretion of the treating physician
Absolute neutrophil count (ANC) > 1500 cells/ mm\^3
Hemoglobin >= 9 g/dL
Platelets > 100,000 per mm\^3

Exclusion criteria

Exclusion Criteria:

Expecting to conceive or father children for the duration of the trial through 4 months after T cell infusion
Active autoimmune disease: Participants with active autoimmune disease requiring immunosuppressive therapy are excluded. Case by case exemptions are possible with approval by principal investigator (PI)
Corticosteroid therapy at a dose equivalent of >15 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 ADT
Active uncontrolled infection: human immunodeficiency virus (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
Uncontrolled concurrent illness: Participants may not have uncontrolled or concurrent illness including, but not limited to, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia that would limit compliance with study requirements
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 > 15 mg prednisone (or equivalent) per day, unless otherwise approved by PI
Significant underlying neurologic disease: Study participants must not have significant active underlying neurologic disease, unless approved by PI. Peripheral neuropathy related to diabetes or prior chemotherapy is acceptable
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 with no bridging therapy options according to the treating medical oncologist. The specific bridging treatment plan must be documented in the Electronic Medical Record (EMR) by the treating medical oncologist within 2 weeks of signing informed consent

Study design

Phase: Phase 1 / Phase 2
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Sequential assignment
Masking: None (open label)
Enrollment: 48 participants (estimated)

Study arms

Experimental
Treatment (STEAP1 CART, enzalutamide)
Patients undergo leukapheresis then receive cyclophosphamide IV and fludarabine IV on days -5, -4 and -3 and STEAP1 CART IV on day 0. Patients may receive enzalutamide PO on day 0 then QD in the absence of disease progression or unacceptable toxicity. Patients also undergo a tumor biopsy at baseline, day 14 and optionally at progression. Patients additionally undergo blood sample collection, NM bone scan and CT scan, or MRI or PET scan throughout study. Additionally, patients may undergo ECHO or MUGA at screening.
Biological: Anti-STEAP1 CAR T-cells · Procedure: Biopsy Procedure · Procedure: Biospecimen Collection · Procedure: Bone Scan · Procedure: Computed Tomography · Drug: Cyclophosphamide · Procedure: Echocardiography Test · Drug: Enzalutamide · Drug: Fludarabine · Procedure: Leukapheresis · Procedure: Magnetic Resonance Imaging · Procedure: Multigated Acquisition Scan · Procedure: Positron Emission Tomography

Interventions

BiologicalAnti-STEAP1 CAR T-cells
Given IV
Also known as: Anti-STEAP1 CAR T Cells, Anti-STEAP1 CAR-T Cells, STEAP1 CAR-T Cells, STEAP1-targeting CAR T-cells
ProcedureBiopsy Procedure
Undergo tumor biopsy
Also known as: Biopsy, BIOPSY_TYPE, Bx
ProcedureBiospecimen Collection
Undergo blood sample collection
Also known as: Biological Sample Collection, Biospecimen Collected, Specimen Collection, Sample Collection
ProcedureBone Scan
Undergo NM bone scan
Also known as: Bone Scintigraphy
ProcedureComputed Tomography
Undergo CT scan
Also known as: CAT, CAT Scan, Computed Axial Tomography, Computerized Axial Tomography, Computerized axial tomography (procedure), Computerized Tomography, CT, CT Scan, tomography
DrugCyclophosphamide
Given IV
Also known as: (-)-Cyclophosphamide, 2H-1,3,2-Oxazaphosphorine, 2-[bis(2-chloroethyl)amino]tetrahydro-, 2-oxide, monohydrate, Asta B 518, B-518, Carloxan, Ciclofosfamida, Ciclofosfamide, Cicloxal, Clafen, Claphene, CP monohydrate, CTX, CYCLO-cell, Cycloblastin, Cycloblastine, Cyclophospham, Cyclophosphamid monohydrate, Cyclophosphamide Monohydrate, Cyclophosphamidum, Cyclophosphan, Cyclophosphane, Cyclophosphanum, Cyclostin, Cyclostine, Cytophosphan, Cytophosphane, Cytoxan, Fosfaseron, Genoxal, Genuxal, Ledoxina, Mitoxan, Neosar, Revimmune, Syklofosfamid, WR- 138719, WR-138719, Frindovyx
ProcedureEchocardiography Test
Undergo ECHO
Also known as: EC, Echocardiography
DrugEnzalutamide
Given PO
Also known as: ASP9785, MDV3100, Xtandi
DrugFludarabine
Given IV
Also known as: Fluradosa
ProcedureLeukapheresis
Undergo leukapheresis
Also known as: Leukocytopheresis, Therapeutic Leukopheresis, Leukocyte Adsorptive Apheresis, White Blood Cell Reduction Apheresis
ProcedureMagnetic Resonance Imaging
Undergo MRI
Also known as: Magnetic Resonance, Magnetic resonance imaging (procedure), Magnetic Resonance Imaging Scan, Medical Imaging, Magnetic Resonance / Nuclear Magnetic Resonance, MR, MR Imaging, MRI, MRI Scan, MRIs, NMR Imaging, NMRI, Nuclear Magnetic Resonance Imaging, sMRI, Structural MRI
ProcedureMultigated Acquisition Scan
Undergo MUGA
Also known as: Blood Pool Scan, Equilibrium Radionuclide Angiography, Gated Blood Pool Imaging, Gated Heart Pool Scan, MUGA, MUGA Scan, Multi-Gated Acquisition Scan, Radionuclide Ventriculogram Scan, Radionuclide Ventriculography, RNVG, SYMA Scanning, Synchronized Multigated Acquisition Scanning, RNV Scan
ProcedurePositron Emission Tomography
Undergo PET scan
Also known as: Medical Imaging, Positron Emission Tomography, PET, PET Scan, Positron emission tomography (procedure), Positron Emission Tomography Scan, Positron-Emission Tomography, proton magnetic resonance spectroscopic imaging, PT

What researchers measure

Primary outcomes

Incidence of grade 3 or higher treatment related unexpected adverse events (AEs) (Phase I)
Toxicity will be graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version (v) 5.0.
Time frame: Up to 28 days post infusion
Incidence of AEs (Phase II)
Toxicity will be graded according to NCI CTCAE v 5.0.
Time frame: Up to 28 days post infusion
Response (Phase II)
Response will be defined as best overall response rate by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and/or Prostate Cancer Working Group 3 (PCWG3) criteria.
Time frame: Up to 1 year post infusion

Secondary outcomes

Progression free survival (PFS)
PFS will be estimated using the method of Kaplan and Meier with time zero being the time of first T cell infusion.
Time frame: At time from initiation of protocol treatment to disease progression or death up to 1 year post infusion
Frequency of participants that achieve an overall response rate (ORR, including complete and partial response) according to RECIST v.1.1 or PCWG3
To measure how well the treatment succeeds in producing the desired effect.
Time frame: Anti-tumor response according to RECIST v1.1 or PCWG3 up to 1 year post infusion
ORR by immune RECIST
Time frame: Up to 1 year post infusion
Frequency of participants that achieve a stable disease (SD) according to RECIST v.1.1 or PCWG3
To measure how well the treatment succeeds in producing the desired effect.
Time frame: Anti-tumor response according to RECIST v1.1 or PCWG3 up to 1 year post infusion
Frequency of participants that achieve a clinical benefit rate (ORR + SD) stable disease RECIST v.1.1 or PCWG3
To measure how well the treatment succeeds in producing the desired effect.
Time frame: Anti-tumor response according to RECIST v1.1 or PCWG3 up to 1 year post infusion
Overall survival (OS)
OS will be estimated using the method of Kaplan and Meier with time zero being the time of first T cell infusion.
Time frame: At time from initiation of protocol treatment to death of any cause up to 1 year post infusion
Prostate specific antigen (PSA) response
PSA responses, defined as \>= 50% reductions in PSA from baseline at any point post baseline assessment will be calculated.
Time frame: At baseline up to 1 year post infusion
Time to response (TTR)
TTR will be assessed from the time of study infusion to time of first documented response (partial response \[PR\] or better).
Time frame: At time from study infusion to time of first documented response up to 1 year post infusion
Duration of response (DOR)
DOR will be assessed from the time of first documented response (PR or better) to time of confirmed disease progression.
Time frame: At time of first documented response to time of confirmed progression up to 1 year post infusion

Study locations

1 of 1 sites recruiting

Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington 98109, United States
- Fred Hutch Intake · Contact · hutchdoc@fredhutch.org · 206-606-1024
- Rosa Nadal Rios, MD, PhD · Principal investigator
Recruiting

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Aug 11, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT06236139
Lead sponsor: Fred Hutchinson Cancer Center
Collaborators: PromiCell Therapeutics, Inc., National Cancer Institute (NCI)
Responsible party: Sponsor
First posted: Feb 1, 2024
Start date: Nov 26, 2024
Primary completion: Mar 30, 2027 (estimated)
Completion: Mar 30, 2027 (estimated)
Last update: Aug 11, 2026

Study contacts

Fred Hutch Intake

Contact

hutchdoc@fredhutch.org

206-606-1024

Rosa Nadal Rios, MD, PhD

principal investigator · Fred Hutch/University of Washington Cancer Consortium

Oversight

Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No

View the source record on ClinicalTrials.gov ↗

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