A Clinical Study to Evaluate the Safety, Tolerability and Preliminary Efficacy of [225Ac]Ac-PSMA-XT Injection in Patients With Metastatic Castration-resistant Prostate Cancer

Inclusion criteria

• have the ability to understand and sign an approved informed consent form (ICF).
• >= 18 years old.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• have a life expectancy >6 months.
• have histological, pathological, and/or cytological confirmation of prostate cancer.
• PSMA Positron Emission Tomography (PET)/Computed Tomography (CT) scan positive
• have a castrate level of serum/plasma testosterone (<50 ng/dL or <1.7 nmol/L).
• have received at least one NAAD (such as enzalutamide and/or abiraterone)； patients must have been previously treated undergone at least 1-2 prior taxane-based chemotherapy regimens or be unsuitable for taxane therapy (unsuitability includes contraindications, investigator-determined ineligibility, or patient refusal) in mCRPC stage.
• progressive mCRPC.
• have adequate organ function。
• Subjects of childbearing potential voluntarily use an effective method of contraception, such as condoms, oral or injectable contraceptives, Intra-uterine device（IUD）,etc., during treatment and within 6 months of the last use of the trial drug.

Exclusion criteria

• Previous treatment with any of the following within 6 months of enrollment: Strontium-89, Samarium-153, Rhenium-186, Rhenium-188, Radium-223, hemi-body irradiation. Previous PSMA-targeted radioligand therapy is not allowed.

Known other malignancies.

• Any systemic anti-cancer therapy (e.g. chemotherapy, immunotherapy or biological therapy within 28 days prior to day of enrollment.
• Known hypersensitivity to the components of the study therapy or its analogs.
• A superscan as seen in the baseline bone scan.
• Patients with a history of Central Nervous System (CNS) metastases.
• Uncontrolled, intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, cardiac arrhythmia, or other severe complications.