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Prostate CancerPhase 1NCT05245006

PET Imaging Study of 89Zr-DFO-YS5 in Men With Prostate Cancer

A Phase 1 study testing 89Zr-DFO-YS5, YS5 antibody and Positron Emission Tomography (PET)/Computerized tomography (CT) in people with Prostate Cancer and Metastatic Castration-resistant Prostate Cancer, run by Robert Flavell, MD, PhD at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

CD46 is an exciting new therapeutic target in prostate cancer, with the antibody drug conjugate FOR46 under investigation in phase I clinical trials. The hypothesis of the study is that CD46 expression, measured via our novel imaging biomarker, is a characteristic feature of mCRPC, and particularly common in the most… Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
89Zr-DFO-YS5, YS5 antibody and Positron Emission Tomography (PET)/Computerized tomography (CT)
Could I receive a placebo?
No, everyone receives an active treatment
How many people
30 participants
Where
1 siteUnited States
Study dates
18 Mar 2022to 31 Jul 2027
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 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Participants must have histologically or cytologically confirmed metastatic, castration resistant prostate cancer (mCRPC).
  • Age >=18 years
  • Eastern Cooperative Oncology Group (ECOG) performance status < 2 (Karnofsky >60%).
  • Demonstrates adequate organ function as defined below:
  • Total bilirubin <1.5 X upper limit of normal (ULN).
  • Aspartate aminotransferase (AST)(serum glutamic-oxaloacetic transaminase (SGOT)) <= 3 X institutional upper limit of normal (ULN).
Show all 10Show fewer
  • Alanine aminotransferase (ALT) (serum glutamic-pyruvic transaminase (SGPT)) <= 3 X institutional ULN.
  • Serum creatinine <=1,5 X institutional ULN or calculated creatinine clearance (Glomerular filtration rate (GFR)) >= 60 mL/min, calculated using the Cockcroft-Gault equation.
  • Ability to understand a written informed consent document, and the willingness to sign it.
  • Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.

Who cannot join

  • Patients who because of age, general medical, or psychiatric condition, or physiologic status cannot give valid informed consent.
  • Any condition that, in the opinion of the Principal Investigator, would impair the patient's ability to comply with study procedures.

Trial locations and contacts

1 site in 1 country.

United States1 site

  • University of California, San Francisco

    San Francisco, California, 94143

Other trials in United States

About this study

Official title: A First-in-Human, Pilot PET Imaging Study of 89Zr-DFO-YS5, an immunoPET Agent for Detecting CD46 Positive Malignancy in Men With Prostate Cancer

CD46 is an exciting new therapeutic target in prostate cancer, with the antibody drug conjugate FOR46 under investigation in phase I clinical trials. The hypothesis of the study is that CD46 expression, measured via our novel imaging biomarker, is a characteristic feature of mCRPC, and particularly common in the most lethal forms of the disease including adenocarcinoma and Small-cell neuroendocrine carcinoma (SCNC). These data will provide crucial information about the feasibility of targeting cluster of differentiation 46 (CD46) in mCRPC, will be used guide the development of novel therapeutic and theranostic agents, to help develop treatments that improve outcomes for men with the most lethal forms of prostate cancer.

Read the detailed description

This single center imaging study involves one microdose of the imaging agent, followed by whole body PET imaging. Imaging data will be acquired in up to four PET studies to determine tumor and normal tissue uptake and dosimetry.

PRIMARY OBJECTIVES:

  1. To determine the optimal time point for imaging (based on analyzing the 4 scans of all participants using 89Zr-DFO-YS5 PET post-injection). (Cohort A)
  2. To determine the optimal antibody dose for imaging using 89Zr-DFO-YS5 PET. (Cohort B).
  3. To determine the sensitivity of metastatic lesion detection in mCRPC using 89Zr-DFO-YS5 PET as compared with conventional imaging (Cohorts C)

SECONDARY OBJECTIVES:

  1. To determine the safety of 89Zr-DFO-YS5.
  2. To determine average organ uptake of 89Zr-DFO-YS5 (Cohort C).
  3. To descriptively report the patterns of intra-tumoral uptake of 89Zr-DFO-YS5 on whole body PET, including by site of disease, uptake by tumor type, inter-tumoral and inter-patient heterogeneity, and tumor-to-background signal (Cohorts C).

OUTLINE: Participants were originally assigned to 1 of 3 cohorts. Cohort B is closed to accrual. Enrollment into Cohort A and C are ongoing.

Cohort A: PET imaging data will be acquired up to four times to determine tumor and normal tissue uptake and dosimetry. The optimized scan time will be used for imaging in Cohorts B and C.

(CLOSED) Cohort B: A dose of cold, non-radiolabeled antibody administered will be varied to determine the optimal antibody dose for image quality. The optimized antibody dose will be used in Cohort C. Participants will be followed for an additional 4-5 weeks after dose administration to assess for adverse events.

Cohort C: PET imaging will be acquired at the optimal time point and optimal antibody dose determined in Cohorts A \& B, and have the option to obtain an repeat scan at the time of disease progression.

All participants will be followed for up to 5 weeks after their first scan to assess for adverse events and will be followed-up until progression. At the time of progression, participants will have the option to receive a repeat scan.

Being tested
89Zr-DFO-YS5, YS5 antibody, Positron Emission Tomography (PET)/Computerized tomography (CT), Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)
Keywords
First-in-Human, immunoPET agent, CD46 positive malignancy
Medical subject headings
Prostatic Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 89Zr-DFO-YS5Drug

    Also called immunoPET agent, Imaging Agent

    3 mCi will be administered intravenously

  • YS5 antibodyBiological

    Also called YS5, Unmodified YS5 antibody

    20 or 50 mg administered intravenously

  • Positron Emission Tomography (PET)/Computerized tomography (CT)Procedure or surgery

    Also called PET/CT, PET/CT Scan, Whole Body PET/CT

    Imaging which combines a CT scan and a PET scan

  • Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)Procedure or surgery

    Also called PET/CT, PET/MRI Scan, Whole Body PET/MRI

    Imaging which combines an MRI scan and a PET scan

Study groups in NCT05245006
Study groupRoleWhat they receive
Cohort A: 89Zr-DFO-YS5ExperimentalParticipants receive one dose of 89Zr-DFO-YS5 up to 3 millicurie (mCi), and undergo a whole body PET performed at 1-4 hours, approximately 20-28 hours, 48-96 hours, and 120-168 hours post injection for up to 4 scans total. The optimized scan time will be used for imaging in cohorts B and C. Participants have the option to receive a repeat 89Zr-DFO-YS5 PET at the time of disease progression.
Receives: Drug: 89Zr-DFO-YS5; Procedure: Positron Emission Tomography (PET)/Computerized tomography (CT); Procedure: Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)
Cohort B: 89Zr-DFO-YS5, YS5 antibodyExperimentalParticipants receive either a 20mg or 50mg dose of YS5 prior to imaging and administration of one dose of up to 3 millicurie (mCi) 89Zr-DFO-YS5 and then complete a single whole body PET scan at the optimal time determined in Cohort A. The optimal dose of unmodified YS5 antibody will be used in the following cohorts C \& D. Participants have the option to receive a repeat 89Zr-DFO-YS5 PET at the time of disease progression.
Receives: Drug: 89Zr-DFO-YS5; Biological: YS5 antibody; Procedure: Positron Emission Tomography (PET)/Computerized tomography (CT); Procedure: Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)
Cohort C: 89Zr-DFO-YS5, Optimal dose YS5 antibodyExperimentalParticipants receive optimal dose of YS5 antibody prior to imaging and administration of one dose of up to 3 millicurie (mCi) 89Zr-DFO-YS5 and then complete a single whole body PET scan at the optimal time determined in Cohort A. Participants have the option to receive a repeat 89Zr-DFO-YS5 PET at the time of disease progression.
Receives: Drug: 89Zr-DFO-YS5; Biological: YS5 antibody; Procedure: Positron Emission Tomography (PET)/Computerized tomography (CT); Procedure: Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Optimal time point for imaging using 89Zr-DFO-YS5 PET post-injection (Cohort A)

    For Cohort A, the optimal time point will be selected based on optimal maximun Standardized uptake value (SUVmax) of metastatic lesions, and ratio of SUVmax to blood pool. Due to the limited samples, the investigator will use all available lesions without considering the location of the lesions or the possible intra-correlation of the lesions from the same participant.

    Measured: Up to 7 days

  2. Optimal antibody dose for imaging using 89Zr-DFO-YS5 PET (Cohort B)

    For Cohort B, the optimal dose of antibody will be selected based on the optimal SUVmax of metastatic lesions, and ratio of SUVmax to blood pool. Due to the limited samples, the investigator will use all available lesions without considering the location of the lesions or the possible intra-correlation of the lesions from the same participant.

    Measured: Up to 7 days

  3. Proportion of participants with metastatic lesions accurately detected in mCRPC using 89Zr-DFO-YS5 PET (sensitivity) (Cohort C)

    Sensitivity is the probability that a test will indicate disease among those with the actual disease: True Positive / (True Positive + False Negative). Lesions will be graded on a semi-quantitative scale ranging from 1-5 as is common for 89Zr-antibody human imaging studies (1 = no uptake, 2 = probably no uptake, 3 = equivocal, 4 = probably positive, 5 = definitely positive). Using as a cut-off to 4 or 5 on the semi-quantitative scale, the sensitivity of 89Zr-DFO-YS5 PET will be descriptively reported on a lesion-per-lesion basis, using as reference standard staging scans including CT or MRI of the chest/abdomen/pelvis and whole body bone scan. The sensitivity estimate will be based on lesion level without considering the location of the lesions or the possible intra-correlation of the lesions from the same patient.

    Measured: Up to 24 months

  4. Median SUVmax (Cohort C)

    The median and range of SUVmax across all metastatic lesions per participant will be descriptively reported using mediastinal blood pool and normal organ as background uptake values will be reported with range of SUVmax.

    Measured: Up to 24 months

  5. Average SUVmax (SUVmax-ave) (Cohort C)

    The average SUVmax-ave across all metastatic lesions per participant will be descriptively reported using mediastinal blood pool and normal organ as background uptake values for all cohorts will be reported with 95% confidence intervals

    Measured: Up to 24 months

Secondary outcomes (7)

  1. Proportion of participants with treatment-related Adverse Events

    The frequency and severity of adverse events following Zr-DFO-YS5 injection will be descriptively reported, using CTCAE version 5.0

    Measured: Up to 3 weeks after last dose administration, approximately 35 days

  2. Average organ uptake of 89Zr-DFO-YS5 (Cohort C)

    Average organ uptake of 89Zr-DFO-YS5 on PET will be estimated.

    Measured: Up to 24 months

  3. Intra-tumoral uptake of 89Zr-DFO-YS5 by tumor type (Cohort C)

    The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported

    Measured: Up to 24 months

  4. Intra-tumoral uptake of 89Zr-DFO-YS5 by Site of Disease (Cohort C)

    The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported

    Measured: Up to 24 months

  5. Inter-tumoral heterogeneity (Cohort C)

    The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported to assess for Inter-tumoral heterogeneity.

    Measured: Up to 24 months

  6. Inter-participant heterogeneity (Cohort C)

    The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported to assess for Inter-participant heterogeneity

    Measured: Up to 24 months

  7. Tumor-to-background signal (Cohort C)

    The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported

    Measured: Up to 24 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted17 Feb 2022
  2. Study start18 Mar 2022
  3. Primary completion31 Jul 2027 (estimated)
  4. Study completion31 Jul 2027 (estimated)

Resources

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
Diagnosis
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
30 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05245006
Sponsor's protocol ID
209210
Other IDs
NCI-2022-01310
Status last verified
Mar 2026
First submitted
8 Feb 2022
Last updated
17 Mar 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing 89Zr-DFO-YS5, YS5 antibody and Positron Emission Tomography (PET)/Computerized tomography (CT) in people with Prostate Cancer and Metastatic Castration-resistant Prostate Cancer, run by Robert Flavell, MD, PhD 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 10 inclusion and 2 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: under way, not looking for participants, as of the sponsor's last update on 17 Mar 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?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Optimal time point for imaging using 89Zr-DFO-YS5 PET post-injection (Cohort A) (time frame: Up to 7 days). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05245006.

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 Mar 2026; AzTrials last refreshed its copy on 7 Nov 2026.

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