NUCLIDIUM Announces First Patient Imaged in Phase 2 Trial for Prostate Cancer

NUCLIDIUM AG, a clinical-stage radiopharmaceutical company, announced today that the first patient has been successfully imaged in a Phase 2 clinical trial evaluating the diagnostic accuracy and safety of the Company’s 61Cu-NU101 radiotracer in patients with metastatic prostate cancer. The 61Cu-NU101 radiotracer is a positron emission tomography (PET) imaging agent that effectively combines high-radiopure Copper-61 with a targeting peptide to specifically bind to Prostate-Specific Membrane Antigen (PSMA), an established biomarker for prostate cancer. This radiotracer is the diagnostic component of NUCLIDIUM’s NU101 theranostic program, paired with the 67Cu-NU101 therapeutic.

In a Phase 1 trial, NUCLIDIUM demonstrated that 61Cu-NU101 was safe and able to detect additional lesions in 50% of patients compared to the currently most sensitive imaging agents. These data supported the opening of the Phase 2 trial, which is statistically powered to compare the sensitivity of tumor lesion detection of 61Cu-NU101 against an 18F-based, FDA-approved PSMA-targeting radiotracer. Secondary endpoints include a sensitivity comparison to CT and bone scans, and a safety evaluation. The trial will enroll approximately 34 patients with biopsy-confirmed metastatic prostate cancer at clinical sites in the United States. Patients will receive a single intravenous dose of 61Cu-NU101, followed by PET/CT imaging at 1 and 4 hours post-dose.

NUCLIDIUM’s 61Cu-NU101 program can be manufactured in 5 minutes at room temperature, allowing for on-demand preparation and seamless integration into existing hospital infrastructure. These manufacturing advantages, coupled with the longer half-life, delayed imaging capability, and beneficial tumor-to-background ratio, further underscore the benefits of this copper-based approach compared with alternative radioligands. Phase 1 data previously presented at the Society of Nuclear Medicine & Molecular Imaging (SNMMI) 2025 Annual Meeting highlight the favorable clinical profile of 61Cu-NU101.

NUCLIDIUM’s lead programs, NU101 in metastatic castration-resistant prostate cancer (mCRPC) and NU201 in metastatic breast cancer (mBC), have demonstrated compelling efficacy and safety in Phase 1/2 diagnostics trials and are advancing into Phase 1/2 theranostics trials. The company’s goal is to expand the reach and clinical profile of radiotheranostics to deliver the full value of the modality and address critical unmet medical needs in oncology and women’s health.