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YS5 antibody

Phase 1

Prostate Cancer | Monoclonal antibody | Oncology |United Therapeutics Corporation|Last Updated: Mar 17, 2026

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDDMCBiomarker
Total Trials1
Total Enrollment30

FDA Designations

No designations recorded

Clinical trial landscape

YS5 antibody · 1 trial · 2 indications

Phase 1 1
NCT05245006PET Imaging Study of 89Zr-DFO-YS5 in Men With Prostate CancerProstate Cancer
ACTIVE NOT_RECRUITING30 Analytics
PHASE1ACTIVE NOT_RECRUITING
PET Imaging Study of 89Zr-DFO-YS5 in Men With Prostate Cancer
Prostate CancerUnlock trial analytics

Study Endpoints

Primary Endpoints

Optimal time point for imaging using 89Zr-DFO-YS5 PET post-injection (Cohort A)
Up to 7 days

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.

Optimal antibody dose for imaging using 89Zr-DFO-YS5 PET (Cohort B)
Up to 7 days

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.

Proportion of participants with metastatic lesions accurately detected in mCRPC using 89Zr-DFO-YS5 PET (sensitivity) (Cohort C)
Up to 24 months

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.

Median SUVmax (Cohort C)
Up to 24 months

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.

Average SUVmax (SUVmax-ave) (Cohort C)
Up to 24 months

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

Secondary Endpoints

Proportion of participants with treatment-related Adverse Events
Up to 3 weeks after last dose administration, approximately 35 days
Average organ uptake of 89Zr-DFO-YS5 (Cohort C)
Up to 24 months
Intra-tumoral uptake of 89Zr-DFO-YS5 by tumor type (Cohort C)
Up to 24 months
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeDIAGNOSTIC

Treatment Arms

ArmTypeDescription
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.
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.
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.

Interventions

NameTypeDescription
89Zr-DFO-YS5DRUG3 mCi will be administered intravenously
YS5 antibodyBIOLOGICAL20 or 50 mg administered intravenously
Positron Emission Tomography (PET)/Computerized tomography (CT)PROCEDUREImaging which combines a CT scan and a PET scan
Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI)PROCEDUREImaging which combines an MRI scan and a PET scan
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites1

Inclusion Criteria: 1. Participants must have histologically or cytologically confirmed metastatic, castration resistant prostate cancer (mCRPC). 2. Age \>=18 years 3. Eastern Cooperative Oncology Group (ECOG) performance status \< 2 (Karnofsky \>60%). 4. Demonstrates adequate organ function as def...

Countries:United States
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Competitive Landscape -Prostate Cancer 254 trials

Frequently asked questions about YS5 antibody

What is YS5 antibody used for in prostate cancer?

YS5 antibody is an investigational monoclonal antibody being studied for use in prostate cancer, specifically in men with metastatic castration-resistant prostate cancer. It is currently in Phase 1 clinical development as a PET imaging agent to visualize tumors. The drug is being evaluated in a clinical trial in the United States.

What does YS5 antibody target?

YS5 antibody is a monoclonal antibody designed to bind to a target on prostate cancer cells, enabling PET imaging of tumors. The specific molecular target is not disclosed in the available information. The antibody is conjugated with a radioactive tracer, 89Zr-DFO, to allow visualization of cancer lesions during imaging.

Who makes YS5 antibody?

YS5 antibody is being developed by United Therapeutics Corporation, a biopharmaceutical company listed on the NASDAQ under the ticker symbol UTHR. The company is conducting a Phase 1 clinical trial of this investigational antibody for prostate cancer imaging in the United States.

What phase is YS5 antibody in?

YS5 antibody is in Phase 1 clinical development. It is an investigational drug and has not been approved by the FDA. The ongoing Phase 1 trial is active but not recruiting participants, with a planned enrollment of 30 patients with prostate cancer.

What clinical trials is YS5 antibody in?

YS5 antibody is being evaluated in one active Phase 1 clinical trial with the identifier NCT05245006. The study, titled "PET Imaging Study of 89Zr-DFO-YS5 in Men With Prostate Cancer," is enrolling 30 participants with prostate cancer or metastatic castration-resistant prostate cancer in the United States. The trial is not randomized or double-blinded.

Is YS5 antibody the same as 89Zr-DFO-YS5?

YS5 antibody is the investigational drug being studied, and in the clinical trial it is administered as the radiolabeled conjugate 89Zr-DFO-YS5. The 89Zr-DFO portion is a radioactive tracer attached to the antibody for PET imaging purposes. The trial specifically evaluates this conjugated form for imaging prostate cancer.