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Study of Ac-225 Rosopatamab Tetraxetan for PSMA PET-Positive Prostate Cancer

This study is testing a new treatment called Ac-225 rosopatamab tetraxetan for men with castration-resistant prostate cancer (CRPC) that shows up on a PSMA PET scan. The study will also use In-111 rosopatamab tetraxetan to see how the treatment spreads in the body. You may be able to join if you are a man aged 18 or older with progressive CRPC. Researchers will be looking to see if the treatment causes side effects and if it can reduce your PSA levels by at least 50%. The study is currently recruiting participants.

Study design
This is a four-part interventional study with a planned enrollment of 93 participants. Some parts of the study involve being randomly assigned to different doses of the treatment.
What's involved
Participants will receive intravenous (IV) infusions of the study medications over 10 minutes. Doses may be given two weeks apart for a total of two doses, or as a single dose, depending on the study part. The study will track your progress for approximately 3 years or until your prostate cancer worsens.
Compensation
Not stated in the trial record.
Follow-up
Participants will be followed for side effects from screening through Week 12, and for PSA response until the end of the study (approximately 3 years) or until PSA progression.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06549465

Study Evaluating Dosimetry, Randomized Dose Optimization, Dose Escalation and Efficacy of Ac-225 Rosopatamab Tetraxetan in Participants With PSMA PET-Positive Castration-Resistant Prostate Cancer (CRPC)

Recruiting
PHASE2Ages 18+InterventionalTreatment
Convergent Therapeutics
~93 participants
Updated 2026-07-20 on ClinicalTrials.gov
What's tested:In-111 rosopatamab tetraxetan45 kBq/kg Ac-225 rosopatamab tetraxetan45 kBq/kg or equivalent fixed dose activity Ac-225 rosopatamab tetraxetan60 kBq/kg Ac-225 rosopatamab tetraxetanSingle dose 22 kBq/kg or equivalent fixed dose activity Ac-225 rosopatamab tetraxetanSingle dose 34 kBq/kg or equivalent fixed dose activity Ac-225 rosopatamab tetraxetan

At a glance

Recruiting sites
9 of 9 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Part 1: Visual evaluation on whole body planar scans (days 1 and 4) with comparison to reference scans for the presence of radiolabeled rosopatamab textraxetan in organs of interest (e.g., liver, circulation, spleen) to determine biodistribution
Measured over Day 1 and Day 4
+7 more outcomes measured

Conditions

PSMA PET-Positive Castration-Resistant Prostate Cancer

Explore related trials

Prostate Carcinoma

Where it's being run

9 sites across 7 states
New York3
California1
Massachusetts1
Missouri1
Nebraska1
North Carolina1
Ohio1

Who to contact

Study Director
[email protected]
CONVERGE01
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Progressive CRPC defined as castrate levels of testosterone and progressing by at least one of the following criteria:
Metastatic disease defined as either or both of the following:
PSMA PET-positive disease, defined as at least one PSMA-positive metastatic lesion and no PSMA-negative lesions
Progression following treatment with ADT and at least one ARSI (e.g., enzalutamide, apalutamide, darolutamide, and/or abiraterone acetate)
The standard of care use (in the setting of metastatic CRPC with significant burden of active bone metastases) of antiresorptive bone-targeted agents (e.g., zoledronic acid, denosumab) is required for all participants without a contraindication, for at least 4 weeks prior to administration of Ac-225 rosopatamab tetraxetan.
Participants with HIV are eligible if they are well-controlled (i.e, an undetectable HIV viral load (\<50 copies/mL) within 6 months of enrollment and a stable ART regimen for at least 6 months prior to enrollment) and at low risk for HIV-related illness
Prior treatment with Lu-177-PSMA-radioligand therapy
Prior treatment with up to only one taxane-based chemotherapy regimen is allowed

Exclusion

Superscans by nuclear medicine/99mTc bone scan
A known malignancy that is progressing or has required active treatment within the past 3 years other than CRPC, which is expected to alter life expectancy or may interfere with CRPC disease assessment
Prior platinum-based chemotherapy
Prior PARP inhibitors (e.g., olaparib or rucaparib)
Prior treatment with Radium-223, Actinium-225, Strontium-89, Samarium-153, Rheunium-186, or Rhenium-188
Participants receiving anti-coagulants or anti-platelet drugs (e.g., aspirin or nonsteroidal anti-inflammatory drugs \[NSAIDs\]) who cannot discontinue use if platelet count decreases to \<50,000
Prior chemotherapy for CRPC. Prior taxane chemotherapy for HSPC is allowed if discontinued ≥1 year prior to randomization
Prior radiopharmaceutical therapy (e.g., Ra-223, Lu-177-PSMA-617, or Lu-177-PSMA-I\&T)
Prior PSMA-targeted therapy, except for bispecific or CAR-T therapies
Prior PSMA-targeted therapy (e.g., antibody-drug conjugates or CAR-T therapy), except for Lu-177-PSMA-radioligand therapy and bispecific or CAR-T therapies

What this trial measures

  • Part 1: Visual evaluation on whole body planar scans (days 1 and 4) with comparison to reference scans for the presence of radiolabeled rosopatamab textraxetan in organs of interest (e.g., liver, circulation, spleen) to determine biodistributionDay 1 and Day 4
  • Part 2: Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) overall, by severity, and leading to discontinuation of study interventionScreening through Week 12
  • Part 2: Proportion of participants who achieve a greater than or equal to 50% decline in prostate-specific antigen (PSA50)Through end of study (approximately 3 years) or until PSA progression as defined by PCWG3 criteria
  • Part 3: Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs) overall, by severity, and leading to discontinuation of study interventionScreening through Week 12
  • Part 3: Determine the recommended Phase 2 dose (RP2D) of Ac-225 rosopatamab tetraxetanDay 1 through 6 weeks
  • Part 3 (Participants treated at RP2D): Proportion of participants who achieve a greater than or equal to 50% decline in prostate-specific antigen (PSA50)Through end of study (approximately 3 years) or until PSA progression as defined by PCWG3 criteria
  • Part 4: Incidence of AEs and SAEs overall, by severity, by relationship to study drug, and leading to discontinuation of study interventionScreening through Week 12
  • Part 4: Determine the recommended Phase 2 dose (RP2D) of Ac-225 rosopatamab tetraxetanThrough end of study (approximately 3 years)