The purpose of this study is to identify the recommended phase 2 doses (RP2Ds) of JNJ-78278343 with cetrelimab (JNJ-63723283) in Part 1 (dose escalation) and to determine safety at the RP2D(s) in Part 2 (dose expansion).
Metastatic castration-resistant prostate cancer (mCRPC) with confirmed adenocarcinoma of the prostate as defined by Prostate Cancer Working Group 3 (PCWG3) Measurable or evaluable disease. Prior treatment for mCRPC with at least 1 prior novel androgen receptor-targeted therapy (ie, abiraterone acetate, apalutamide, enzalutamide, darolutamide), or chemotherapy (eg, docetaxel) Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Adequate organ functions
Exclusion Criteria:
Active autoimmune disease within the 12 months prior to signing consent that requires systemic immunosuppressive medications Toxicity related to prior anticancer therapy that has not returned to Grade less than or equal to (<=) 1 or baseline levels (except for alopecia, vitiligo, Grade <=2 peripheral neuropathy) Solid organ or bone marrow transplantation Known allergies, hypersensitivity, or intolerance to any of the components (eg, excipients) of JNJ-78278343 or cetrelimab Significant infections or serious lung, heart or other medical conditions
