A Study of Radiation Dosimetry, Safety, and Tolerability of Extended Lutetium (177Lu) Vipivotide Tetraxetan Treatment in Chemo-naïve Adults With Metastatic Castration-resistant Prostate Cancer: RADIOpharmaceutical DOSimetry Evaluation (RADIODOSE) Study

Key Inclusion Criteria:

• Signed informed consent must be obtained prior to participation in the study.

• Participants must be adults ≥ 18 years of age.

• Participants must have an ECOG performance status ≤ 1.

• Participants must have histological confirmation of adenocarcinoma of the prostate.

• Participants must be PSMA-positive per 68Ga-PSMA PET/CT scans at baseline

• Participants must have a castrate level of serum/plasma testosterone (< 50 ng/dL or < 1.7 nmol/L) either by pharmaceutical or surgical methods.

• Participants must have progressed only once on prior second generation ARPIs

• Documented progressive mCRPC

• Participants must have ≥ 1 metastatic lesion by conventional imaging that is presenton screening/baseline CT, MRI, or bone scan

• Renal: eGFR ≥ 60 mL/min/1.73m2 using the Chronic Kidney Disease EpidemiologyCollaboration (CKD-EPI) equation.

• Participants must have recovered to ≤ Grade 2 from all clinically significanttoxicities related to prior therapies except alopecia.

Key exclusion Criteria:

• Previous treatment with any of the following within 6 months of study enrollment:Strontium 89, Samarium-153, Rhenium-186, Rhenium-188, Radium-223, hemi-bodyirradiation

• Any previous radioligand therapy.

• Prior treatment with cytotoxic chemotherapy for metastatic castration-resistant ormetastatic hormone-sensitive prostate cancer (mHSPC) (e.g., taxanes, platinum,estramustine, vincristine, methotrexate, etc.), immunotherapy or biological therapy [including monoclonal antibodies]. [Note: Taxane exposure (maximum 6 cycles) in theadjuvant or neoadjuvant setting is allowed if 12 months have elapsed sincecompletion of this adjuvant or neoadjuvant therapy. Prior treatment withsipuleucel-T is allowed].

• Concurrent therapies: cytotoxic chemotherapy, immunotherapy, radioligand therapy,PARP inhibitor, biological, or investigational therapy

• History of myocardial infarction (MI), angina pectoris, or coronary artery bypassgraft (CABG) within 6 months prior to ICF signature and/or clinically activesignificant cardiac disease

• Concurrent serious acute or chronic nephropathy and/or moderate to severe renalimpairment as determined by the principal investigator.

• Diagnosed with other active malignancies that are expected to alter life expectancyor may interfere with disease assessment

• Sexually active males unwilling to use a condom during intercourse while takingstudy treatment and for 14 weeks after stopping study treatment.

• Concurrent urinary outflow obstruction or unmanageable urinary incontinence

• History of somatic or psychiatric disease/condition that may interfere with the aimsand assessments of the study.

Other protocol-defined inclusion/exclusion criteria may apply.