A Study of JNJ-78278343, a T-Cell-Redirecting Agent Targeting Human Kallikrein 2 (KLK2), for Advanced Prostate Cancer

Prior treatment

• Toxicity related to prior anticancer therapy has not adequately recovered
  • Prior/Concomitant Therapy
• Prior treatment with human kallikrein (KLK) 2-targeted therapy
• Received, or are receiving, medications that suppress the immune system within 3 days prior to the first dose of study drug
• Received or plans to receive any live, attenuated vaccine within 4 weeks prior to the first dose of study drug
  • Prior/Concurrent Medical Conditions
• Diagnosis of cancer other than prostate cancer within 2 years prior to the first dose of study drug
• Solid organ or bone marrow transplantation
• Major clotting diseases within one month prior to the first dose of study drug
• Active autoimmune disease within 12 months prior to the first dose of study drug
• Major diseases of heart and blood vessels within 6 months prior to the first dose of study drug
• Known positive test result for human immunodeficiency virus (unless stable on antiretroviral therapy with undetectable viral load)

Other illness

• Disease conditions
• Active infection
• Clinically significant lung diseases
• Active or chronic hepatitis B or hepatitis C infection
• Any serious underlying medical conditions or other issue that would impair the ability of the participant to receive or tolerate the planned treatment

Other

• Active central nervous system (CNS) involvement

• Confirmed adenocarcinoma of the prostate which has spread to other body parts
• Part 1: Prior treatment with at least 1 prior novel androgen receptor (AR)-targeted therapy or chemotherapy
• Measurable or evaluable disease
• Concurrent use of any other anticancer treatment must be discontinued for at least 2 weeks before the first dose of study drug
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Prior surgical removal of testicles; or, for participants who have not undergone surgical removal of testicles, must be receiving ongoing androgen deprivation therapy (ADT) with a gonadotropin releasing hormone analog