Castration-Resistant Prostate CarcinomaPhase 2NCT05924672
Efficacy of Ra-223 in PSMA PET Optimally Selected Patients
A Phase 2 study testing Radium-223, PSMA Positron Emission Tomography (PET) Scan and Technetium Tc 99M Medronate in people with Castration-Resistant Prostate Carcinoma and Metastatic Malignant Neoplasm in the Bone, run by University of California, San Francisco at 1 site in United States.
Trial summary
This phase II trial studies how well prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans (in combination with bone scans) work in selecting patients for Ra-223 radiation therapy that have castration-resistant prostate cancer that has spread from where it first started (primary site) to… Read more about this study
- Who is it for?
- Ages 18 years and older, men only
- Conditions the study is for
- Castration-Resistant Prostate Carcinoma, Metastatic Malignant Neoplasm in the Bone, Stage IVB Prostate Cancer AJCC v8
- What is being tested?
- Radium-223, PSMA Positron Emission Tomography (PET) Scan and Technetium Tc 99M Medronate
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 2 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Aug 2024to 31 Mar 2027
- Phase
- Phase 2
- 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
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male participants >= 18 years of age on the day of signing informed consent
- Castrate level of serum testosterone at study entry (< 50 ng/dL), checked within three months of enrollment
- Patient is a candidate for standard of care Ra-223 therapy
- Bone only disease on PSMA PET using a Food and Drug Administration (FDA) approved PSMA targeted PET radiopharmaceutical
- Note: Nodal disease on PSMA PET that is less than 1 cm in short axis and without evidence of change in size over the past six months on conventional imaging is allowed
- Positivity on PSMA PET is defined as uptake greater than the liver that is not attributable to physiologic activity
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- Histologically confirmed prostate adenocarcinoma that is progressive by Prostate Cancer Working Group 3 (PCWG3) criteria at the time of study entry
- Prior progression on at least one second generation androgen signaling inhibitor including abiraterone, apalutamide, darolutamide, and/or enzalutamide
- Platelets > 100,000/microliter (mcL)
- Hemoglobin (Hgb) > 9.0 g/dL
- White blood cells (WBC) > 2.5
- Albumin > 3.0 g/dL
- Adverse events related to prior anti-cancer treatment must have recovered to =< Grade 2
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
- For patients who have partners of childbearing potential: Partner and/or patient must use a method of birth control with adequate barrier protection, deemed acceptable by the principal investigator during the study and for 3 months after last study drug administration
- 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
- Ability to understand and the willingness to sign a written informed consent document
Who cannot join
- Prior treatment with Lutetium-177 (177Lu)-PSMA-617, Radium-223, Strontium-89, Samarium-153, Rhenium-186, Rhenium-188
- Prior exposure to taxane-based chemotherapy.
- Note: Exposure is defined as two or more cycles of taxane-based agents
- Any systemic anti-cancer therapy (e.g., chemotherapy, immunotherapy or biological therapy, including monoclonal antibodies) within 21 days prior to the first day of treatment
- Greater than 75% bone involvement, based on PSMA PET
- Presence of visceral metastases, untreated central nervous system metastases, or untreated epidural or spinal cord involvement
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- Prior treatment with radioligand therapy
- Blood transfusion within past 45 days
- 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
About this study
This phase II trial studies how well prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans (in combination with bone scans) work in selecting patients for Ra-223 radiation therapy that have castration-resistant prostate cancer that has spread from where it first started (primary site) to the bones (bone metastasis). Ra-223 is a type of therapy that emits radiation. Radiation gives off energy which can kill tumor cells and other cells that may support the tumor cells. Ra-223 is given by infusion into the veins, where it is absorbed by the bones. PSMA PET is a type of scan used to detect prostate cancer tumors. PSMA is a radioactive tracer that binds to a specific protein that is found on prostate tumor cells. The PSMA tracer shows the areas on the PET scan where tumor cells are active. A PET scan uses a special camera to detect the energy given off from radioactive tracers (such as PSMA) to make detailed pictures of areas where the tracer accumulates in the body. The PET scan is often combined with a magnetic resonance imaging (MRI) or computed tomography (CT) scan, which helps to map the locations where PSMA has accumulated. PSMA PET scans may be able to select patients that will benefit the most from Ra-223 treatment.
Read the detailed description
PRIMARY OBJECTIVE:
- To determine the PSA50 response rate of participants treated with radium Ra 223 dichloride (Ra-223).
SECONDARY OBJECTIVES:
- To determine the median overall survival (mOS) of participants treated with Ra-223.
II. To determine the PSA30 response rate of participants treated with Ra-223. III. To determine the time to the first skeletal symptomatic event. IV. To characterize the safety profile of Ra-223 treatment. V. To compare the lesion based PSMA PET response based on sodium fluoride (NaF) PET/technetium Tc-99m medronate (MDP) single photon emission computed tomography (SPECT) uptake.
EXPLORATORY OBJECTIVES; I. To compare the PSA response stratified by PSMA PET tumor volume. II. To determine the location of progression by location. III. Safety on subsequent treatment with PSMA radioligand therapy (RLT).
OUTLINE:
Participants undergo NaF PET/CT or MDP scan within 45 days prior to standard of care (SOC) Ra-223 intravenously (IV). Treatment repeats every 28 days for 6 cycles in the absence of disease progression or unacceptable toxicity. Participants then undergo a PSMA PET/CT between 30-60 days after the last dose of Ra-223. Participants also undergo collection of blood samples during screening, on the first day of every Ra-223 cycle, and at 30 days after the last dose. Participants may also undergo a NaF PET/CT or MDP scan during treatment as clinically indicated, and/or CT scans during screening and treatment as clinically indicated.
After completion of Ra-223 treatment, participants are followed up at 30 days, and then every 3-6 months.
- Conditions
- Castration-Resistant Prostate Carcinoma, Metastatic Malignant Neoplasm in the Bone, Stage IVB Prostate Cancer AJCC v8
- Being tested
- Radium-223, PSMA Positron Emission Tomography (PET) Scan, Technetium Tc 99M Medronate
- Medical subject headings
- Prostatic Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Radium-223Drug
Also called Ra-223, BAY 88-8223, BAY88-8223, Radium 223 Dichloride
Given IV
PSMA Positron Emission Tomography (PET) ScanProcedure or surgery
Also called Prostate-specific Membrane Antigen (PSMA) PET, PSMA PET
Undergo PSMA PET/CT
Technetium Tc 99M MedronateDrug
Also called (99m)Tc-Medronate, 121524-79-6, 99mTc-MDP, TechneScan MDP, Technetium Tc 99m Methylene Diphosphonate
Undergo MDP
| Study group | Role | What they receive |
|---|---|---|
| Treatment (NaF PET/CT/MDP, Ra-223, PSMA PET) | Experimental | Patients undergo NaF PET/CT or MDP scan within 45 days prior to cycle 1 day 1. Patients then receive standard of care Ra-223 IV on day 1 of each cycle. Treatment repeats every 28 days for 6 cycles in the absence of disease progression or unacceptable toxicity. Patients then undergo PSMA PET/CT over 45-60 minutes between 30-60 days after the last dose of Ra-223. Patients also undergo collection of blood samples during screening, on day 1 of every Ra-223 cycle, and at 30 days after the last dose of Ra-223. Patients may also undergo NaF PET/CT or MDP scans during Ra-223 treatment as clinically indicated, and/or CT scans during screening and Ra-223 treatment as clinically indicated. Receives: Drug: Radium-223; Procedure: PSMA Positron Emission Tomography (PET) Scan; Drug: Technetium Tc 99M Medronate |
What is being measured
The primary outcome is the main question the study is designed to answer.
PSA50 response rate
The proportion of patients who achieve a greater than 50% decline from baseline prostate specific antigen (PSA) (PSA50) drawn prior to C1D1, at any point in the treatment course, will be descriptively reported along with 95% binomial confidence interval. It will be compared with the historical control by binomial test. A confirmation repeat PSA will be drawn after the initial PSA50 response to confirm the result. A PSA50 will only be counted if two PSA showing a 50% decline are measured.
Measured: Up to 6 months
Secondary outcomes (5)
PSA30 response rate
The proportion of patients who achieve a greater than 30% decline from baseline PSA (PSA30) drawn prior to cycle 1 day 1 (C1D1), at any point in the treatment course, will be descriptively reported along with 95% binomial confidence interval. It will be compared with the historical control by binomial test.
Measured: Up to 6 months
Overall Survival
Overall survival The time to event will be defined by the duration from the first date of study therapy to date of death from any cause. We will estimate the survival function using the Kaplan-Meier method, and obtain its 95% confidence bands over the survival times. The median overall survival time and 95% confidence interval of it will be derived from the estimated survival functions.
Measured: Up to 2 years
Time to first skeletal symptomatic event
The time to the first skeletal symptomatic event will measure the time to the first new symptomatic pathological bone fracture, spinal cord compression, tumor-related orthopedic surgical intervention, or requirement for radiation therapy to relieve bone pain, whichever occurs first. We will also estimate the survival function using the Kaplan-Meier method, and obtain its 95% confidence bands over the survival times. The median survival time and 95% confidence interval of it will be derived from the estimated survival functions.
Measured: Up to 30 days after the last dose of Ra-223 treatment
Proportion of participants reporting treatment-related adverse events
The incidence and severity of adverse events related to study treatment will be descriptively reported using CTCAE v5.0.
Measured: Up to 30 days after the last dose of Ra-223 treatment
Compare the lesion based PSMA PET response based on paired NaF PET / MDP uptake
Up to five lesions per patient will be measured by a board certified nuclear medicine physician. For each lesion the maximum SUV (SUVmax) will be measured on PSMA PET and NaF PET. Additionally, the SUVmax on the end of study PSMA PET will also be measured. As there is an underestimation of uptake on MDP bone scan compared to PET, we will multiply the uptake measured on MDP SPECT by 2.3 to correct for the differences in recovery coefficients between the two imaging technologies based on prior comparisons. The percent change in the PSMA PET uptake between baseline and end of study will be measured. A Spearman's rank correlation will be used to compare the baseline NaF uptake for each lesion with the percent change of PSMA PET SUVmax.
Measured: Up to 30 days after the last dose of Ra-223 treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jun 2023
- Study start30 Aug 2024
- Primary completion7 Jan 2026
- Study completion31 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Castration-Resistant Prostate CarcinomaStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 2 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Collaborators
- Bayer Healthcare Pharmaceuticals, Inc./Bayer Schering Pharma
- Responsible party
- Sponsor
- Investigators
- Thomas A Hope, MD, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05924672
- Sponsor's protocol ID
- 23923
- Other IDs
- NCI-2023-04656
- Status last verified
- Jan 2026
- First submitted
- 20 Jun 2023
- Last updated
- 14 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of Ra-223 in PSMA PET Optimally Selected Patients
- ClinicalTrials.gov ID
- NCT05924672
- Acronym / sponsor ID
- 23923
- Conditions
- Castration-Resistant Prostate Carcinoma, Metastatic Malignant Neoplasm in the Bone, Stage IVB Prostate Cancer AJCC v8
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 2 participants (actual)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Collaborators
- Bayer Healthcare Pharmaceuticals, Inc./Bayer Schering Pharma
- Study start
- 30 Aug 2024 (actual)
- Primary completion
- 7 Jan 2026 (actual)
- Study completion
- 31 Mar 2027 (estimated)
- First posted
- 29 Jun 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This phase II trial studies how well prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans (in combination with bone scans) work in selecting patients for Ra-223 radiation therapy that have castration-resistant prostate cancer that has spread from where it first started (primary site) to the bones (bone metastasis). Ra-223 is a type of therapy that emits radiation. Radiation gives off energy which can kill tumor cells and other cells that may support the tumor cells. Ra-223 is given by infusion into the veins, where it is absorbed by the bones. PSMA PET is a type of scan used to detect prostate cancer tumors. PSMA is a radioactive tracer that binds to a specific protein that is found on prostate tumor cells. The PSMA tracer shows the areas on the PET scan where tumor cells are active. A PET scan uses a special camera to detect the energy given off from radioactive tracers (such as PSMA) to make detailed pictures of areas where the tracer accumulates in the body. The PET scan is often combined with a magnetic resonance imaging (MRI) or computed tomography (CT) scan, which helps to map the locations where PSMA has accumulated. PSMA PET scans may be able to select patients that will benefit the most from Ra-223 treatment.
Detailed description
PRIMARY OBJECTIVE:
- To determine the PSA50 response rate of participants treated with radium Ra 223 dichloride (Ra-223).
SECONDARY OBJECTIVES:
- To determine the median overall survival (mOS) of participants treated with Ra-223.
II. To determine the PSA30 response rate of participants treated with Ra-223. III. To determine the time to the first skeletal symptomatic event. IV. To characterize the safety profile of Ra-223 treatment. V. To compare the lesion based PSMA PET response based on sodium fluoride (NaF) PET/technetium Tc-99m medronate (MDP) single photon emission computed tomography (SPECT) uptake.
EXPLORATORY OBJECTIVES; I. To compare the PSA response stratified by PSMA PET tumor volume. II. To determine the location of progression by location. III. Safety on subsequent treatment with PSMA radioligand therapy (RLT).
OUTLINE:
Participants undergo NaF PET/CT or MDP scan within 45 days prior to standard of care (SOC) Ra-223 intravenously (IV). Treatment repeats every 28 days for 6 cycles in the absence of disease progression or unacceptable toxicity. Participants then undergo a PSMA PET/CT between 30-60 days after the last dose of Ra-223. Participants also undergo collection of blood samples during screening, on the first day of every Ra-223 cycle, and at 30 days after the last dose. Participants may also undergo a NaF PET/CT or MDP scan during treatment as clinically indicated, and/or CT scans during screening and treatment as clinically indicated.
After completion of Ra-223 treatment, participants are followed up at 30 days, and then every 3-6 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Treatment (NaF PET/CT/MDP, Ra-223, PSMA PET) | Experimental | Drug: Radium-223, Procedure: PSMA Positron Emission Tomography (PET) Scan, Drug: Technetium Tc 99M MedronatePatients undergo NaF PET/CT or MDP scan within 45 days prior to cycle 1 day 1. Patients then receive standard of care Ra-223 IV on day 1 of each cycle. Treatment repeats every 28 days for 6 cycles in the absence of disease progression or unacceptable toxicity. Patients then undergo PSMA PET/CT over 45-60 minutes between 30-60 days after the last dose of Ra-223. Patients also undergo collection of blood samples during screening, on day 1 of every Ra-223 cycle, and at 30 days after the last dose of Ra-223. Patients may also undergo NaF PET/CT or MDP scans during Ra-223 treatment as clinically indicated, and/or CT scans during screening and Ra-223 treatment as clinically indicated. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (17 listed)
- Male participants >= 18 years of age on the day of signing informed consent
- Castrate level of serum testosterone at study entry (< 50 ng/dL), checked within three months of enrollment
- Patient is a candidate for standard of care Ra-223 therapy
- Bone only disease on PSMA PET using a Food and Drug Administration (FDA) approved PSMA targeted PET radiopharmaceutical
- Histologically confirmed prostate adenocarcinoma that is progressive by Prostate Cancer Working Group 3 (PCWG3) criteria at the time of study entry
Key exclusion criteria (9 listed)
- Prior treatment with Lutetium-177 (177Lu)-PSMA-617, Radium-223, Strontium-89, Samarium-153, Rhenium-186, Rhenium-188
- Prior exposure to taxane-based chemotherapy.
- Any systemic anti-cancer therapy (e.g., chemotherapy, immunotherapy or biological therapy, including monoclonal antibodies) within 21 days prior to the first day of treatment
- Greater than 75% bone involvement, based on PSMA PET
- Presence of visceral metastases, untreated central nervous system metastases, or untreated epidural or spinal cord involvement
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Radium-223Also: Ra-223, BAY 88-8223, BAY88-8223, Radium 223 DichlorideGiven IV | Drug | Treatment (NaF PET/CT/MDP, Ra-223, PSMA PET) |
| PSMA Positron Emission Tomography (PET) ScanAlso: Prostate-specific Membrane Antigen (PSMA) PET, PSMA PETUndergo PSMA PET/CT | Procedure or surgery | Treatment (NaF PET/CT/MDP, Ra-223, PSMA PET) |
| Technetium Tc 99M MedronateAlso: (99m)Tc-Medronate, 121524-79-6, 99mTc-MDP, TechneScan MDP, Technetium Tc 99m Methylene DiphosphonateUndergo MDP | Drug | Treatment (NaF PET/CT/MDP, Ra-223, PSMA PET) |
Primary outcome
PSA50 response rate
Time frame: Up to 6 months
The proportion of patients who achieve a greater than 50% decline from baseline prostate specific antigen (PSA) (PSA50) drawn prior to C1D1, at any point in the treatment course, will be descriptively reported along with 95% binomial confidence interval. It will be compared with the historical control by binomial test. A confirmation repeat PSA will be drawn after the initial PSA50 response to confirm the result. A PSA50 will only be counted if two PSA showing a 50% decline are measured.
5 secondary outcomes
PSA30 response rate
Time frame: Up to 6 months
Overall Survival
Time frame: Up to 2 years
Time to first skeletal symptomatic event
Time frame: Up to 30 days after the last dose of Ra-223 treatment
Proportion of participants reporting treatment-related adverse events
Time frame: Up to 30 days after the last dose of Ra-223 treatment
Compare the lesion based PSMA PET response based on paired NaF PET / MDP uptake
Time frame: Up to 30 days after the last dose of Ra-223 treatment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jan 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Thomas A Hope, MD principal investigator
University of California, San Francisco
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Radium-223, PSMA Positron Emission Tomography (PET) Scan and Technetium Tc 99M Medronate in people with Castration-Resistant Prostate Carcinoma and Metastatic Malignant Neoplasm in the Bone, run by University of California, San Francisco 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 17 inclusion and 9 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 14 Jan 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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?
PSA50 response rate (time frame: Up to 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 14 Jan 2026; AzTrials last refreshed its copy on 7 Nov 2026.