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)

A Phase 2, Open-label 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

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: Convergent Therapeutics · Industry
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

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.

Conditions

• PSMA PET-Positive Castration-Resistant Prostate Cancer

Interventions

Type	Name	Description
BIOLOGICAL	In-111 rosopatamab tetraxetan	A single dose of 148 ± 37 MBq In-111 rosopatamab tetraxetan will be administered as an IV infusion over a period of 10 minutes.
BIOLOGICAL	45 kBq/kg Ac-225 rosopatamab tetraxetan	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.
BIOLOGICAL	55 kBq/kg Ac-225 rosopatamab tetraxetan	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.
BIOLOGICAL	60 kBq/kg Ac-225 rosopatamab tetraxetan	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.

Timeline

• Start date: 2024-08-06
• Primary completion: 2025-12-01
• Completion: 2027-04-01
• First posted: 2024-08-12
• Last updated: 2025-08-24

Locations

9 sites across 1 country: United States

Regulatory

• FDA-regulated drug study