Phase 3 Study of Xaluritamig vs Cabazitaxel or Second Androgen Receptor-Directed Therapy in Participants With Progressive Metastatic Castration-Resistant Prostate Cancer

Inclusion Criteria:

• Participant has provided informed consent prior to initiation of any study-specificactivities/procedures.

• Age ≥ 18 years (or ≥ legal age within the country if it is older than 18 years) atthe time of signing the informed consent.

• Participant must have histological, pathological, and/or cytological confirmation ofadenocarcinoma of the prostate.

• mCRPC with ≥ 1 metastatic lesion that is present on baseline computed tomography (CT), magnetic resonance imaging (MRI), or bone scan imaging obtained within 28 daysprior to enrollment.

• Evidence of progressive disease, defined as 1 or more PCWG3 criteria:

• Serum PSA progression defined as 2 consecutive increases in PSA over a previousreference value measured at least 1 week prior. The minimal start value is 2.0ng/mL.

• Soft-tissue progression defined as an increase ≥ 20% in the sum of the diameter (SOD) (short axis for nodal lesions and long axis for non-nodal lesions) of alltarget lesions based on the smallest SOD since treatment started or theappearance of one or more new lesions.

• Progression of bone disease: evaluable disease or new bone lesion(s) by bonescan (2+2 PCWG3 criteria, Scher et al, 2016).

• Participants must have had a prior orchiectomy and/or ongoing androgen-deprivationtherapy and a castrate level of serum testosterone (< 50 ng/dL or < 1.7 nmol/L).

• Prior treatment with at least one ARDT.

• Prior treatment with one taxane therapy. Prior treatment with docetaxel in thehormone-sensitive setting is permitted. Participants who received two or more priorchemotherapy regimens in the castrate-resistant setting are not eligible.

• Prior treatment with radioligand therapy (RLT), radionuclide therapy (Radium-223),poly ADP-ribose polymerase (PARP) inhibitor, or immune checkpoint inhibitor ispermitted.

• Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1.

• Adequate organ function.

Key Exclusion Criteria:

Prior & Concomitant Therapy:

• Prior six transmembrane epithelial antigen of the prostate 1 (STEAP1)-targetedtherapy.

• Any anticancer therapy, immunotherapy, or investigational agent within 4 weeks priorto the first dose of study treatment, not including androgen suppression therapy.

• Prior Prostate-Specific Membrane Antigen (PSMA) radioligand therapy (RLT) within 2months of the first dose of study treatment unless participants received < 2 cyclesof therapy. Participants who received 1 cycle of PSMA RLT within 35 days prior tothe first dose of study treatment are also excluded.

• Participants who started a bisphosphonate or denosumab regimen within 4 weeks priorto the first dose of study treatment.

• Radiation therapy within 4 weeks prior to the first dose of study treatment (orlocal or focal radiotherapy within 2 weeks prior to the first dose of studytreatment).

• Concurrent cytotoxic chemotherapy, immunotherapy, radioligand therapy, PARPinhibitor, biological therapy, or investigational therapy.

Disease Related:

• Participants with a history of central nervous system (CNS) metastasis.

• Unresolved toxicities from prior anti-tumor therapy with CTCAE version 5.0 eventsgrade above 1 or baseline, with the exception of alopecia or toxicities that arestable and well controlled AND there is an agreement to allow inclusion by both theinvestigator and the sponsor.