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Comparison of 177Lu-PSMA-617 and 225Ac-PSMA-617 in a Prostatectomy Model (LUTACT Trial)
There is evidence that Actinium-225 Prostate-Specific Membrane Antigen (225Ac-PSMA) has a potentially higher level of efficacy than 177 Lutetium Prostate-Specific Membrane Antigen (177Lu-PSMA) as a radioligand therapy. This single center, pilot study will compare differences in the mechanisms of actinium-225 and lutetium-177 radioligand therapies (RLT) in participants with high or very high risk localized or locoregional prostate cancer planning on undergoing a prostatectomy.
PRIMARY OBJECTIVES: 1. Compare the tumor absorbed dose between 177Lu-PSMA-617 and 225Ac-PSMA-617. 2. Compare the immunologic priming of 177Lu-PSMA-617 and 225Ac-PSMA-617 with controls in prostatectomy specimens. SECONDARY OBJECTIVES: 1. Determine the safety and tolerability of neoadjuvant 177Lu-PSMA-617 and 225Ac-PSMA-617 in participants with high or very high-risk prostate cancer planning to undergo radical prostatectomy. 2. Estimate PSA response for 177Lu-PSMA-617 and 225Ac-PSMA-617 treatment. 3. Estimate the rate of pathologic response in participants treated with 177Lu-PSMA-617 and 225Ac-PSMA-617. EXPLORATORY OBJECTIVES: 1. Determine the relationship between percent cell necrosis and tumor absorbed dose for both 177Lu-PSMA-617 and 225Ac-PSMA-617. 2. Compare the heterogeneity of cell necrosis for 177Lu-PSMA-617 and 225Ac-PSMA-617. 3. Compare messenger ribonucleic acid (mRNA) expression profiles of tumor treated with 177Lu-PSMA-617, 225Ac-PSMA-617, and controls. 4. Compare mRNA expression profiles of tumors in participants who achieve a PSA50 response and those that do not. 5. Compare mRNA expression profiles of tumors from archival tissue and at time of prostatectomy. 6. Compare the percent cell necrosis between participants receiving a single cycle of PSMA RLT versus participants receiving two cycles of PSMA RLT. 7. Compare the change in uptake on PSMA Positron Emission Tomography (PET) to PSA response and percent cell necrosis. 8. Descriptively evaluate cell necrosis at the tumor margins. OUTLINE: Participants will be assigned to 1 of 2 cohorts to receive 177Lu-PSMA-617 or 225Ac-PSMA-617. Additional participants undergoing prostatectomy without RLT will be enrolled as a control group. Participants enrolled in the RLT cohorts will receive 1 to 2 cycles of PSMA radioligand therapy up to 6 weeks apart before a scheduled, non-investigational, prostatectomy four weeks after PSMA radioligand therapy. Participants receiving RLT will be followed up for a safety assessment 6 weeks after surgery and for up to 60 months after prostatectomy for long term follow-up. Participants in the prostatectomy only cohort will have safety and long-term follow-up performed as part of clinical care up to 24 months after surgery.
Age
18 - No limit years
Sex
MALE
Healthy Volunteers
No
University of California, San Francisco
San Francisco, California, United States
Start Date
July 8, 2025
Primary Completion Date
April 30, 2027
Completion Date
April 30, 2028
Last Updated
December 1, 2025
45
ESTIMATED participants
177 Lutetium Prostate-Specific Membrane Antigen 617
DRUG
Actinium-225 Prostate-Specific Membrane Antigen 617
DRUG
Non-investigational, Prostatectomy
PROCEDURE
Prostate Tissue Collection
PROCEDURE
Single-photon emission computed tomography (SPECT)/Computerized tomography (CT)
PROCEDURE
Blood Sample Collection
PROCEDURE
Lead Sponsor
Thomas Hope
Collaborators
NCT06842498
NCT05691465
Data Source & Attribution
This clinical trial information is sourced from ClinicalTrials.gov, a service of the U.S. National Institutes of Health.
Modifications: This data has been reformatted for display purposes. Eligibility criteria have been parsed into inclusion/exclusion sections. Location data has been geocoded to enable distance-based search. For the authoritative and most current information, please visit ClinicalTrials.gov.
Neither the United States Government nor Clareo Health make any warranties regarding the data. Check ClinicalTrials.gov frequently for updates.
View ClinicalTrials.gov Terms and ConditionsNCT04550494