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A Study of [225Ac]Ac-AKY-2519 in Patients With Metastatic Castration-Resistant Prostate Cancer

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

Status
Recruiting
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07581184
Acronym
BActinium-1
Enrollment
138
Registered
2026-05-12
Start date
2026-06-17
Completion date
2032-06-01
Last updated
2026-09-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

B7H3, Castration Resistant Metastatic Prostate Cancer, mCRPC, mCRPC (Metastatic Castration-resistant Prostate Cancer), Prostate Cancer

Keywords

AKY-2519, BActinium-1, AKY-2519-01, B7-H3

Brief 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.

Interventions

DRUG[225Ac]Ac-AKY-2519 (therapeutic)

\[225Ac\]Ac-AKY-2519 Injection

DRUG[64Cu]Cu-AKY-2519 (imaging)

\[64Cu\]Cu-AKY-2519 Injection

Sponsors

Aktis Oncology, Inc.
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy 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

Design outcomes

Primary

MeasureTime frameDescription
Occurrence of adverse events by severity and occurrence of serious adverse events (SAEs) in participants who received [225Ac]Ac-AKY-2519Up to 30 days following last administration of [225Ac]Ac-AKY-2519An 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
Occurrence of dose-limiting toxicity (DLT) in mCRPC participants with and without prior 177Lu-PSMA-617 exposureFrom first administration of [225Ac]Ac-AKY-2519 to the end of Cycle 1 (each cycle is 28 days)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.

Secondary

MeasureTime frameDescription
Occurrence of adverse events by severity and occurrence of serious adverse events (SAEs) in participants who received [64Cu]Cu-AKY-2519Up to 30 days following last administration of [64Cu]Cu-AKY-2519An 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 will be reported.
Objective Response Rate (ORR)Up to 30 days following last administration of [225Ac]Ac-AKY-2519ORR is defined as the percentage of patients who achieved a best overall response of confirmed Complete Response (CR) or Partial Response (PR), as determined by the investigator based on PCWG3-modified RECIST v1.1.
Duration of Response (DoR)Up to 5 years after first administrationDuration of Response (DoR) is defined as the time from the date of the first documentation of objective response (complete response \[CR\] or partial response \[PR\]) to the date of the first objective documentation of progressive disease (PD) or death due to any cause.
Progression-Free Survival (PFS)Up to 5 years after first administrationPFS is defined as the time from treatment initiation to the first documented disease progression per RECIST 1.1 or death due to any cause, whichever occurs first.
Prostate Specific Antigen (PSA) >= 50% Response Rate (PSA50)Up to 30 days following last administration of [225Ac]Ac-AKY-2519Will assess PSA decline of \>= 50% from baseline (PSA50), using the Prostate Cancer Working Group 3 (PCWG3) criteria.
Prostate Specific Antigen (PSA) >= 90% Response Rate (PSA90)Up to 30 days following last administration of [225Ac]Ac-AKY-2519Will assess PSA decline of \>= 90% from baseline (PSA90), using the Prostate Cancer Working Group 3 (PCWG3) criteria.

Countries

United States

Contacts

CONTACTPaul Schwarzenberger, MD
AKY-2519-01inquiries@aktisoncology.com+1-857-216-8482

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 16, 2026