Comparing 177Lu-PSMA-617 and 225Ac-PSMA-617 for High-Risk Prostate Cancer

This study is comparing two treatments, 177 Lutetium Prostate-Specific Membrane Antigen 617 (177Lu-PSMA-617) and Actinium-225 Prostate-Specific Membrane Antigen 617 (225Ac-PSMA-617), for men with high-risk prostate cancer. Both treatments are given intravenously (into a vein) or intra-arterially (into an artery). Researchers want to see how much radiation dose each treatment delivers to the tumor and how they affect the body's immune cells. You may be able to join if you are an adult man with prostate cancer that is considered high-risk, and you are planning to have surgery to remove your prostate (prostatectomy). The study aims to understand which treatment is more effective at targeting the cancer. The current status of this study is unclear.

Study design
This is an interventional study planning to enroll 45 men. It is a pilot study comparing two different radioligand therapies.
What's involved
You would undergo a prostatectomy, have prostate tissue collected, and receive imaging procedures like SPECT/CT scans. The study measures tumor absorbed dose at 1 week and immune cell infiltration at 1 day and at the time of prostatectomy.
Compensation
Not stated in the trial record.
Follow-up
The primary endpoints are measured at 1 week and at 1 day/time of prostatectomy.

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NCT07054346

Comparison of 177Lu-PSMA-617 and 225Ac-PSMA-617

Recruiting
PHASE1Ages 18+InterventionalTreatment
Thomas Hope
~45 participants
Updated 2026-08-28 on ClinicalTrials.gov
What's tested:177 Lutetium Prostate-Specific Membrane Antigen 617Actinium-225 Prostate-Specific Membrane Antigen 617Non-investigational, ProstatectomyProstate Tissue CollectionSingle-photon emission computed tomography (SPECT)/Computerized tomography (CT)Blood Sample Collection

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Mean of tumor absorbed dose (Cohorts 1 and 2)
Measured over 1 week
+1 more outcome measured
Prostate Cancer
Prostate Cancer (Diagnosis)
High-risk Prostate Cancer
Localized Prostate Carcinoma
Very High Risk Prostate Carcinoma
1 sites across 1 states
California1
  • Thomas A Hope, MD · PRINCIPAL_INVESTIGATOR · University of California, San Francisco

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Eligibility criteria

Inclusion

Note: this applies to treatment cohorts only; there are no requirements for tissue-only cohorts (Control Group) 10. Ability to understand and the willingness to sign a written informed consent document. 11. Participants must provide consent to comply to recommended radioprotection precautions during study. 12. Participants must use adequate contraception and not donate sperm while on study drug and for at least 14 weeks after the last study treatment.
  • Mean of tumor absorbed dose (Cohorts 1 and 2)1 week

    The mean tumor absorbed dose on post-treatment SPECT imaging within 7 days of the first radioligand treatment (RLT) will be obtained by using MIM Software to measure absorbed dose and researchers will manually segment activity in the dominant prostate tumor while carefully excluding any activity within the bladder using a threshold of 5 Gray. Using this segmented volume, the mean dose within the tumor in Gray for each participant and standard deviation will be calculated and reported descriptively for Cohorts 1 and 2. A two-sample t-test comparing the dose between Cohort 1 and Cohort 2 and Analysis of Variance (ANOVA) model to compare the dose between different treatment/fractionation modalities within each cohort will be performed.

  • Rate of Cluster of differentiation 3 positive (CD3+) T cell infiltration1 day, at time of prostatectomy

    Immunohistochemistry will be performed using standard methods, and stained slides will be scanned using an automated microscope scanner. Five randomly selected fields (0.25 mm\^2) from each participant's primary tumor will be captured. Using color-specific algorithms, CD3+ cell counts will be determined, and the mean of each of the five quantified fields will be used. We will use a two-sample t-test or ANOVA model comparing the CD3+ cell counts between Cohort 1 and Cohort 2 with participants who have not undergone prostatectomy enrolled in the biospecimen protocol, respectively.