RecruitingInterventionalPhase 1

BActinium-1: A Phase 1b, Multicenter, Open-label Study to Evaluate the Safety and Efficacy of Intravenous Administration of B7-H3 Radiopharmaceutical ([225Ac]Ac-AKY-2519) in Metastatic Castration-Resistant Prostate Cancer

NCT ID: NCT07581184Sponsor: Aktis Oncology, Inc.Last updated: 2026-05-12

Summary

This is a Phase 1b, multi-center, open-label study to evaluate the safety, tolerability, dosimetry, and pharmacokinetics (PK) of \[64Cu\]Cu-AKY-2519 and/or \[225Ac\]Ac-AKY-2519, as well as the preliminary anti-tumor activity of \[225Ac\]Ac-AKY-2519 in participants with metastatic castration-resistant prostate cancer (mCRPC) with and without prior exposure to 177Lu-PSMA-617 (PLUVICTO™).

Detailed description

This Phase 1b study consists of a dose escalation portion and a backfill portion. The dose escalation portion will investigate ascending doses of \[225Ac\]Ac-AKY-2519 across two cohorts enrolling in parallel: * Cohort A: participants with metastatic castration-resistant prostate cancer (mCRPC) with NO prior exposure to 177Lu-PSMA-617 (PLUVICTO™) and * Cohort B: participants with metastatic castration-resistant prostate cancer (mCRPC) with prior exposure to 177Lu-PSMA-617 (PLUVICTO™) The backfill portion may enrich in two select dose levels from each cohort (Cohort A: mCRPC 177Lu-PSMA-617 (PLUVICTO™)-naïve; Cohort B: mCRPC 177Lu-PSMA-617 (PLUVICTO™)-experienced) to gather further information on the safety and efficacy and to determine the recommended phase 2 dose (RP2D) for each cohort.

Arms & interventions

Drug[225Ac]Ac-AKY-2519 (therapeutic)
\[225Ac\]Ac-AKY-2519 Injection
Drug[64Cu]Cu-AKY-2519 (imaging)
\[64Cu\]Cu-AKY-2519 Injection

Outcome measures

Primary

Occurrence of adverse events by severity and occurrence of serious adverse events (SAEs) in participants who received [225Ac]Ac-AKY-2519
An AE is defined as any untoward medical occurrence in a participant administered study drug, which does not necessarily have to have a causal relationship with the study drug. The number of patients experiencing an AE and the number of patients experiencing an SAE will be reported. Up to 30 days following last administration of \[225Ac\]Ac-AKY-2519
Time frame: Up to 30 days following last administration of [225Ac]Ac-AKY-2519
Occurrence of dose-limiting toxicity (DLT) in mCRPC participants with and without prior 177Lu-PSMA-617 exposure
Dose-limiting toxicities (DLTs) is defined as any predefined AE occurring during the DLT observation period, except those that are clearly and incontrovertibly due to extraneous circumstances. The number of patients who experience a DLT will be reported separately for each cohort and by dose level within each cohort.
Time frame: From first administration of [225Ac]Ac-AKY-2519 to the end of Cycle 1 (each cycle is 28 days)

Secondary

Occurrence of adverse events by severity and occurrence of serious adverse events (SAEs) in participants who received [64Cu]Cu-AKY-2519
Time frame: Up to 30 days following last administration of [64Cu]Cu-AKY-2519
Objective Response Rate (ORR)
Time frame: Up to 30 days following last administration of [225Ac]Ac-AKY-2519
Duration of Response (DoR)
Time frame: Up to 5 years after first administration
Progression-Free Survival (PFS)
Time frame: Up to 5 years after first administration
Prostate Specific Antigen (PSA) >= 50% Response Rate (PSA50)
Time frame: Up to 30 days following last administration of [225Ac]Ac-AKY-2519
Prostate Specific Antigen (PSA) >= 90% Response Rate (PSA90)
Time frame: Up to 30 days following last administration of [225Ac]Ac-AKY-2519

Eligibility criteria

Sex: MaleAge: 18 Years and olderHealthy volunteers: No

Inclusion Criteria: * Age ≥ 18 years * Histologic or cytologic confirmation of prostatic adenocarcinoma * ECOG Performance Status of 0 or 1 * Adequate end-organ function * Ability to give informed consent and comply with study requirements * Patients with CNS metastases are eligible if they have received therapy and are neurologically stable, asymptomatic and not receiving corticosteroids * Castrate levels of serum testosterone (\< 50 ng/dL) * Documented disease progression on most recent prior line of therapy, either by PSA or imaging-based progression * Cohort B: Received 2 or more prior doses of 177Lu-PSMA-617 (PLUVICTO) Exclusion Criteria: * Prior treatment with more than 2 Androgen receptor pathway inhibitors (ARPIs) and/or more than 1 taxane-based therapy in the mCRPC setting * Prior treatment with a targeted radiotherapy o Exception: Cohort B is required to have had at least 2 prior doses of 177Lu-PSMA-617 (PLUVICTO) * Prior treatment with a B7-H3 targeted therapy * Received an investigational agent within the previous 28 days * Impaired cardiac function or clinically significant cardiac disease * Concurrent serious medical condition that would impair study participation or impact the assessment of treatment related toxicity

Study locations (2)

Biogenix Molecular, LLC

Miami, Florida, 33165

Recruiting

Study Coordinator · Contact

786-791-1799 jjoseph@cira-health.com

BAMF Health

Grand Rapids, Michigan, 49503

Recruiting

Study Coordinator · Contact

616-330-2735 ResearchClinicalTeam@bamfhealth.com