AMG509: This study is evaluating how safe and tolerable targeted immunotherapy (called Xaluritamig) is in people with high-risk biochemical recurrent (BCR) non-metastatic castration-sensitive prostate cancer (nmCSPC)A Phase 1b, Open-label, Multicenter Study Evaluating the Safety, Tolerability, and Efficacy of Xaluritamig in Subjects With High-risk Biochemical Recurrence of Nonmetastatic Castration-sensitive Prostate Cancer After Definitive Therapy

Exclusion

• Present evidence of metastatic disease in conventional CT scan and/or bone scan
• Participants that present prostate-specific membrane antigen (PSMA)-positive lesions in the 68Ga-PSMA-11 or the piflufolastat F18 positron emission tomography (PET) scan may be enrolled if the conventional imaging does not show suspicion of metastatic disease.

• Prior hormonal therapy, exceptions include:

  • Neoadjuvant/adjuvant therapy to treat prostate cancer ≤ 36 months in duration and ≥ 9 months before enrollment, or
  • A single dose or a short course (≤ 6 months) of hormonal therapy given for rising PSA ≥ 9 months before enrollment.
• Prior cytotoxic chemotherapy, aminoglutethimide, ketoconazole, abiraterone acetate, or enzalutamide for prostate cancer.
• Abiraterone acetate or enzalutamide are allowed if administered in a neoadjuvant setting ≤ 36 months in duration and ≥ 9 months before enrollment.
• Prior systemic biologic therapy, including immunotherapy, for prostate cancer.
• If, in the investigator's opinion, salvage therapy is the preferred intervention.
• Confirmed history or current autoimmune disease or other diseases resulting in permanent immunosuppression or requiring permanent immunosuppressive therapy.
• Participant with symptoms and/or clinical signs and/or radiographic signs that indicate an acute and/or uncontrolled active systemic infection within 7 days prior to the first dose of study treatment.
• Requirement for chronic systemic corticosteroid therapy (prednisone dose > 10 mg/day or equivalent) or any other immunosuppressive therapies (including anti tumor necrosis factor alpha [TNFα] therapies).