RecruitingPhase 2

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)

United States93 participantsStarted 2024-08-06

Plain-language summary

This is a four-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. Part 4 will be an extended regimen in dose escalation and expansion. 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 qualifying for Part 4 will initially receive two doses (dose administration on Day 1 and Day 15) at the dose level selected in Part 2, followed by a single third dose of Ac-225 rosopatamab tetraxetan administered approximately 12 weeks after completion of the Part 2 fractionated dosing regimen. The starting dose level for Part 4 will be 22 kBq/kg (or fixed activity equivalent). Dose limiting toxicities (DLTs) will be monitored following administration of the third dose in Part 4 to determine the recommended phase 2 dose (RP2D) of a third dose of Ac-225 rosopatamab tetraxetan. 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.

Who can participate

Age range

18 Years

Sex

MALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Serum PSA progression as defined by PCWG3 (rising PSA consisting of two consecutive increases measured at least 3 weeks apart, of a rise of \>25%, and with an absolute rise of 2.0 ng/mL.
. Soft tissue progression defined as a ≥20% increase in the sum of the diameter (short axis for nodal lesions and long axis for non-nodal lesions) of all target lesions based on the smallest sum of the diameter since the previous treatment was started or the appearance of one or more new lesions by CT/magnetic resonance imaging (MRI)
. Progression of bone disease defined by PCWG3 as evaluable disease or new bone lesions by bone scan
. Identification of new soft tissue or bone lesions on PSMA PET imaging
. Parts 1, 2, 3, and 4: Documented M1 disease on conventional imaging (CT/MRI of the chest/abdomen/pelvis and/or Technetium 99m \[99mTc\] whole-body bone scan)

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

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

Timeframe: Day 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 intervention

Timeframe: Screening through Week 12

Part 2: Proportion of participants who achieve a greater than or equal to 50% decline in prostate-specific antigen (PSA50)

Timeframe: 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 intervention

Timeframe: Screening through Week 12

Part 3: Determine the recommended Phase 2 dose (RP2D) of Ac-225 rosopatamab tetraxetan

Timeframe: Day 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)

Trial details

NCT IDNCT06549465

SponsorConvergent Therapeutics

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2027-04-20

Contact for this trial

Study Director

CONVERGE01 CONVERGE01@convergentrx.com

View on ClinicalTrials.gov More PSMA PET-Positive Castration-Resistant Prostate Cancer trials

Plain-language summary

Who can participate

Age range

18 Years

Sex

MALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Serum PSA progression as defined by PCWG3 (rising PSA consisting of two consecutive increases measured at least 3 weeks apart, of a rise of \>25%, and with an absolute rise of 2.0 ng/mL.
. Soft tissue progression defined as a ≥20% increase in the sum of the diameter (short axis for nodal lesions and long axis for non-nodal lesions) of all target lesions based on the smallest sum of the diameter since the previous treatment was started or the appearance of one or more new lesions by CT/magnetic resonance imaging (MRI)
. Progression of bone disease defined by PCWG3 as evaluable disease or new bone lesions by bone scan
. Identification of new soft tissue or bone lesions on PSMA PET imaging
. Parts 1, 2, 3, and 4: Documented M1 disease on conventional imaging (CT/MRI of the chest/abdomen/pelvis and/or Technetium 99m \[99mTc\] whole-body bone scan)

What they're measuring

Timeframe: Day 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 intervention

Timeframe: Screening through Week 12

Part 2: Proportion of participants who achieve a greater than or equal to 50% decline in prostate-specific antigen (PSA50)

Timeframe: 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 intervention

Timeframe: Screening through Week 12

Part 3: Determine the recommended Phase 2 dose (RP2D) of Ac-225 rosopatamab tetraxetan

Timeframe: Day 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)