A Phase 1 interventional study of JNJ-78278343 and JNJ-87189401 in Prostatic Neoplasms, sponsored by Janssen Research & Development, LLC. Recruiting at 20 sites in 5 countries. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-28.
Sponsored by Janssen Research & Development, LLC · Phase 1, Interventional, and Treatment
The purpose of Parts 1, 2A, and 2B of the study is to determine the recommended regimen for Phase 2 (RP2Rs) of combination of JNJ-87189401 with JNJ-78278343 and the purpose of Part 2C of this study is to determine how safe the RP2R(s) of the combination of JNJ-87189401 and JNJ-78278343 is, with or without apalutamide. Part 3 of this study evaluates the safety of the triplet combination of JNJ-87189401 and JNJ-78278343 with standard of care (SOC) lutetium Lu-177 vipivotide tetraxetan. Part 4 of this study further evaluates the safety of the triplet combination of JNJ-87189401 and JNJ-78278343 with JNJ-101556143 in participants with advanced prostate cancer.
Exclusion Criteria:
Participants will receive JNJ-78278343 + JNJ-87189401 escalated sequentially in Part 1 to select a recommended Phase 2 regimen (RP2R).
Drug: JNJ-78278343 · Drug: JNJ-87189401
Participants with different disease settings in Parts 2A and 2B will receive JNJ-78278343+JNJ-87189401 at the RP2R selected in Part 1. Participants in Part 2C will receive apalutamide plus continued treatment with JNJ-87189401+JNJ-78278343 doublet.
Drug: JNJ-78278343 · Drug: JNJ-87189401 · Drug: Apalutamide
Participants will receive JNJ-78278343 + JNJ-87189401 at one or more RP2R (s) selected in Part 1 along with standard of care (SOC) treatment with lutetium Lu-177 vipivotide tetraxetan. Dosing of JNJ-78278343+JNJ-87189401 will be escalated sequentially, as per study evaluation team (SET) decision.
Drug: JNJ-78278343 · Drug: JNJ-87189401 · Drug: Lutetium Lu-177 Vipivotide Tetraxetan
Participants will receive JNJ-78278343 + JNJ-87189401 at one or more RP2R (s) along with JNJ-101556143. Dosing of JNJ-78278343+JNJ-87189401 along with JNJ-101556143 will be escalated sequentially to determine the RP2R of the combinations.
Drug: JNJ-78278343 · Drug: JNJ-87189401 · Drug: JNJ-101556143
JNJ-78278343 will be administered.
Also known as: KLK2-CD3, Pasritamig
JNJ-87189401 will be administered.
Also known as: PSMAxCD28
Apalutamide will be administered.
Lutetium Lu-177 Vipivotide Tetraxetan will be administered as SOC treatment.
JNJ-101556143 will be administered.
Also known as: HLD-0915
Parts 1, 2C, 3 and 4: Number of Participants With Dose Limiting Toxicity (DLT)
DLTs are specific adverse events (AEs) and are defined as any of the following: high grade non-hematologic toxicity or hematologic toxicity.
Time frame: Up to 21 days after first combination dose of study drugs
Number of Participants with Adverse Events (AEs) by Severity
An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study. Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0 with the exception of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome events, which will be graded by American Society for Transplantation and Cellular Therapy (ASTCT) guidelines. Severity scale ranges from grade 1 (mild) to grade 5 (death). Grade 1= mild, Grade 2= moderate, Grade 3= severe, Grade 4= life-threatening and Grade 5= death related to adverse event.
Time frame: Up to 4 years 8 months
Serum Concentrations of JNJ-87189401 and JNJ-78278343
Serum samples will be analyzed to determine concentrations of JNJ-87189401 and JNJ-78278343.
Time frame: Up to 4 years 8 months
Plasma Concentration of JNJ-101556143
Plasma samples will be analyzed to determine concentrations of JNJ-101556143.
Time frame: Up to 4 years 8 months
Number of Participants With Antibodies to JNJ-87189401 and JNJ-78278343
Number of participants with antibodies to JNJ-87189401 and JNJ-78278343 will be reported.
Time frame: Up to 4 years 8 months
Objective Response Rate (ORR)
ORR is defined as the proportion of participants who have a partial response (PR) or better according to response evaluation criteria in solid tumors (RECIST) version 1.1 without evidence of bone progression according to Prostate Cancer Clinical Trials Working Group 3 (PCWG3).
Time frame: Up to 4 years 8 months
Radiographic Progression-Free Survival (rPFS)
rPFS is defined time from the date of first dose of study drug until the date of objective disease progression or death, whichever comes first.
Time frame: Up to 4 years 8 months
Prostate Specific Antigen (PSA) Response Rate
PSA response rate is defined as the percentage of participants with a confirmed decline of PSA of 50 percent (%) or more from baseline.
Time frame: Up to 4 years 8 months
Duration of Response (DOR)
DOR is defined for participants who achieved response (PR or better) as the time between the date of initial documentation of response (PR or better) to the date of first documented evidence of progressive disease, as defined in the PCWG3, or death due to any cause, whichever occurs first.
Time frame: Up to 4 years 8 months
Plan to share: Yes — The data sharing policy of Johnson \& Johnson Innovative Medicine is available at innovativemedicine.jnj.com/our-innovation/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at yoda.yale.edu
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