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)

Conditions

• PSMA PET-Positive Castration-Resistant Prostate Cancer

Eligibility Criteria

Sex

MALE

Age

18 Years - N/A

Healthy Volunteers

Not accepted

Interventions

• In-111 rosopatamab tetraxetan — BIOLOGICAL
  A single dose of 148 ± 37 MBq In-111 rosopatamab tetraxetan will be administered as an IV infusion over a period of 10 minutes.
• 45 kBq/kg Ac-225 rosopatamab tetraxetan — BIOLOGICAL
  45 kBq/kg Ac-225 rosopatamab tetraxetan will be administered as an IV infusion over a period of 10 minutes. Doses will be given two weeks apart for a total of two doses.
• 55 kBq/kg Ac-225 rosopatamab tetraxetan — BIOLOGICAL
  55 kBq/kg Ac-225 rosopatamab tetraxetan will be administered as an IV infusion over a period of 10 minutes. Doses will be given two weeks apart for a total of two doses.
• 60 kBq/kg Ac-225 rosopatamab tetraxetan — BIOLOGICAL
  60 kBq/kg Ac-225 rosopatamab tetraxetan will be administered as an IV infusion over a period of 10 minutes. Doses will be given two weeks apart for a total of two doses.

Study Details

This is a three-part study evaluating the safety and efficacy of a PSMA-directed radioantibody (rosopatamab tetraxetan, conjugated to either In-111 or Ac-225). Part 1 will consist of one administration of In-111-rosopatamab tetraxetan to characterize the biodistribution of the radioantibody to target organs and prostate cancer lesions. Participants then will be enrolled into either Part 2 (Dose Optimization) or Part 3 (Dose Escalation and Expansion) depending on their prior treatment history. Participants qualifying for Part 2 will be randomized to receive Ac-225 rosopatamab tetraxetan in a single fractionated cycle (dose administration on Day 1 and Day 15) at either 45 or 60 kBq/Kg. Participants qualifying for Part 3 must have received prior Lu-177-PSMA-radioligand therapy and will receive Ac-225 rosopatamab tetraxetan in a single fractionated cycle at 45, 55, or 60 kBq/Kg. Dose limiting toxicities (DLTs) will be monitored in Part 3 to determine the recommended phase 2 dose (RP2D), and the study may enroll additional participants to be treated with the RP2D dose level. Participants enrolled into any part will attend study visits which will include blood samples, electrocardiogram (ECG), radiographic imaging, and physical examinations along with other assessments.

Key Dates

Start date

Aug 6, 2024

Status verified

Aug 2025

Primary completion

Dec 31, 2025

Completion

Apr 30, 2027

Study Design

Enrollment

60 participants (estimated)

Allocation

NON_RANDOMIZED

Intervention model

SEQUENTIAL

Primary purpose

TREATMENT

Arms

• Experimental: Part 1: 148 ± 37 MBq In-111 rosopatamab tetraxetan
• Experimental: Part 2: 45 kBq/kg Ac-225 rosopatamab tetraxetan
• Experimental: Part 2: 60 kBq/kg Ac-225 rosopatamab tetraxetan
• Experimental: Part 3: Dose Escalation and Expansion
  Participants previously treated with Lu-177-PSMA-radioligand therapy will be assigned to receive one of the three dose levels (45 kBq/kg, 55 kBq/kg, or 60 kBq/kg) depending on the dose limiting toxicities (DLTs) observed.

Primary Outcome Measure

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 [ Time Frame: Day 1 and Day 4 ]

Central Contacts

• Study Director
  CONVERGE01
  [email protected]

Locations (9)

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