Imaging Study of [89Zr]DFO-YS5 for Cancer Detection

June 17, 2026 updated by: Robert Flavell, MD, PhD

A Pilot PET Imaging Study of [89Zr]DFO-YS5 for Detection of Cancer in Patients With Various Malignancies

This is a single-center, pilot, PET-imaging study of the novel radiotracer 89Zirconium-89 DFO conjugated to the YS5 monoclonal antibody ([89Zr]DFO-YS5) in participants with nerve sheath tumor, bladder cancer, or advanced solid tumor neoplasms.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

PRIMARY OBJECTIVE:

I. To descriptively report patterns of [89Zr]DFO-YS5 uptake on whole-body PET.

SECONDARY OBJECTIVE:

II. To determine the safety of [89Zr]DFO-YS5.

OUTLINE:

Participants will be administered a single dose of [89Zr]DFO-YS5 followed by whole-body positron emission tomography (PET) imaging at a single time point. All participants will be followed for adverse events for approximately Participants in the main study will be followed for adverse events for approximately 1 month after [89Zr]DFO-YS5 radiotracer administration.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94143

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Histological or cytological confirmation of malignant peripheral nerve sheath tumor, bladder cancer, or solid tumor neoplasm.
  2. At least one soft tissue lesion measurable at 1 cm or greater in short axis measurement on cross sectional imaging such as Computerized tomography (CT), magnetic resonance imaging (MRI), or Positron Emission Tomography (PET)/CT (scan imaging as documented in the medical record). Exception: For participants with localized bladder cancer (pre-cystectomy), lesions smaller than 1 centimeter (cm) are permitted, provided there is cystoscopic confirmation of a bladder mass.
  3. Clinically able to undergo PET-CT imaging or PET-MRI.
  4. Age ≥ 18 years.
  5. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2 or Karnofsky ≥ 50% (see Appendix 1).

  6. Adequate organ function as defined below:

    • Total bilirubin: ≤ 1.5 x institutional upper limit of normal (ULN) (unless elevated due to Gilbert's syndrome and direct bilirubin is within normal limits).
    • Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase (SGOT)): ≤ 3 x ULN.
    • Alanine aminotransferase (ALT) (serum glutamic-pyruvic transaminase (SGPT)): ≤ 3 x ULN.
    • Estimated creatinine clearance: ≥ 60 mL/min, calculated using the Cockcroft-Gault equation.
  7. Females of reproductive potential (defined below) must be willing to undergo a urine or serum pregnancy test (i.e., human chorionic gonadotropin test) within 72 hours before administration of [89Zr]DFO-YS5. A female is considered to NOT be of reproductive potential (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice), if they meet either of the following two criteria: (1) has reached a postmenopausal state (≥ 12 continuous months of amenorrhea with no identified cause other than menopause); or (2) has undergone surgical sterilization (i.e., hysterectomy and/or bilateral oophorectomy for removal of uterus and/or ovaries). The result of the urine or serum pregnancy test must be negative in order to initiate the [89Zr]DFO-YS5 administration. If a urine pregnancy test is positive or equivocal, a confirmatory a serum pregnancy test is required. The individual must be excluded from participation if the serum pregnancy result is positive. Pregnant individuals are excluded from this study because there is an unknown but potential risk for adverse effects in the unborn child secondary to treatment of the study participant with [89Zr]DFO-YS5.
  8. Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or endpoints of this study are eligible.
  9. Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

  1. Individuals with a contraindication to PET-CT imaging (e.g., severe claustrophobia) or PET-MRI (e.g., implanted devices, metallic objects, or other implants). Participants must be able to undergo either PET-CT or PET-MRI.
  2. Individuals who are pregnant or breastfeeding/chest-feeding. Pregnant and breastfeeding/chest-feeding individuals are excluded because there is an unknown but potential risk for adverse effects in the unborn/nursing child secondary to treatment of the study participant with [89Zr]DFO-YS5. Females of childbearing potential must have a negative pregnancy test before administration of [89Zr]DFO-YS5, as outlined in inclusion criterion #7. Breastfeeding/chest-feeding should be discontinued before administration of [89Zr]DFO-YS5.

  3. Individuals who do not agree to follow the below contraception requirements:

    Females of reproductive potential (defined below) must agree to use two forms of contraception, consisting of a barrier method (such as condoms) in combination with a secondary complementary method (such as hormonal, Intrauterine device (IUD), etc.), or strict abstinence, for the duration of study participation and for 1 month after administration of [89Zr]DFO-YS5. A female is considered to NOT be of reproductive potential (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice), if they meet either of the following two criteria: (1) has reached a postmenopausal state (≥ 12 continuous months of amenorrhea with no identified cause other than menopause); or (2) has undergone surgical sterilization (i.e., hysterectomy and/or bilateral oophorectomy for removal of uterus and/or ovaries).

  4. Hypersensitivity to [89Zr]DFO-YS5 or any of its excipients.
  5. Individuals with any condition or social circumstance that, in the opinion of the investigator, would impair the participant's ability to comply with study procedures.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Treatment ([89Zr]DFO-YS5)
Participants will be administered a single, intravenous microdose (1.0 - 3.0 mCi) of [89Zr]DFO-YS5, followed by whole-body positron emission tomography (PET) imaging conducted 120-168 hours after [89Zr]DFO-YS5 administration (i.e., on Day 6-8). Participants will be followed for treatment-emergent adverse events for up to 35 days.
Drug: [89Zr]DFO-YS5
Given intravenously (IV)
Other Names:
  • 89Zirconium-89 DFO conjugated to the YS5 monoclonal antibody
Procedure: Positron Emission Tomography (PET)-Magnetic resonance imaging (MRI)
Participants may receive a whole-body PET-MRI or a whole body PET-CT
Other Names:
  • PET-MRI
  • PET/MRI
Procedure: Positron Emission Tomography (PET)-Computerized tomography (CT)
Participants may receive a whole-body PET-CT or a whole-body PET-MRI
Other Names:
  • PET/CT
  • PET-CT

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean maximum standard uptake value (SUVmax-avg) on Positron Emission Tomography (PET) scan
Time Frame: Up to 8 days
A volume of interest (VOI) will be placed around each lesion, and the calculated maximum standard uptake value (SUVmax) will be recorded for each lesion. Adjusted SUVmax data will then be averaged across up to 15 lesions within a given patient (SUVmax-avg) at each time point. In order to avoid clustering effects, analyses will be limited to the five largest osseous metastases, five largest lymph node metastases, and five largest visceral/soft tissue metastases. Metastatic lesion location, size (bidimensional axial measurement), and SUVmax will be tabulated. This will be conducted for all lesions.
Up to 8 days
Median intra-tumoral SUVmax
Time Frame: Up to 8 days
The median and range for intra-tumoral SUVmax within metastatic lesions will be descriptively reported, to assess for intra-tumoral heterogeneity and differences in uptake by site of disease.
Up to 8 days
Tumor-to-background signal (Ratio)
Time Frame: Up to 8 days
The tumor-to-background signal refers to comparing the standardized uptake value (SUV) of a lesion (tumor) to the SUV of a nearby normal organ or tissue that serves as a "background" reference. The ratio of the tumor-to-background signal on PET scan (normal organ as background uptake values) will be calculated as the SUVmax of tumor divided by the SUV of background organ
Up to 8 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of participants with reported treatment-emergent adverse events
Time Frame: Up to 8 days
The proportion of participants with reported treatment-emergent Adverse events (AEs) will be classified and graded according to the NCI CTCAE version. 5.0 by severity and type evaluated from the time of administration through the Day 6-8 Visit (120-168 hours post-dose).
Up to 8 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Robert Flavell, MD, PhD

Collaborators

Fortis Therapeutics, Inc.
Kyntra Bio

Investigators

  • Principal Investigator: Robert Flavell, MD, University of California, San Francisco

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

August 1, 2026

Primary Completion (Estimated)

September 30, 2029

Study Completion (Estimated)

September 30, 2029

Study Registration Dates

First Submitted

June 17, 2026

First Submitted That Met QC Criteria

June 17, 2026

First Posted (Actual)

June 24, 2026

Study Record Updates

Last Update Posted (Actual)

June 24, 2026

Last Update Submitted That Met QC Criteria

June 17, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 26921
  • NCI-2026-04664 (Registry Identifier: NCI Clinical Trials Reporting Program (CTRP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified data may be shared with study collaborators during the course of data collection.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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