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

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