A Study of JNJ-98768111 in Participants With Advanced Prostate Cancer

A Phase 1 Trial of JNJ-98768111, an Antibody Drug Conjugate (ADC) Targeting Human Kallikrein-2 (KLK2) for Advanced Prostate Cancer

The purpose of Part 1 of this study is to find out how safe JNJ-98768111 is and the most suitable dose (recommended phase 2 dose [RP2D]) regimen(s) of JNJ-98768111. The purpose of Part 2 of this study is to find out how safe JNJ-98768111 is at the RP2D regimen(s) in participants with advanced prostate cancer (cancer of the prostate, a male reproductive gland found below the bladder, which has spread extensively to other parts of the body).

Study Overview

• Status: Recruiting
• Conditions: Prostatic Neoplasms
• Intervention / Treatment: Drug: JNJ-98768111

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Study Contact; Phone Number: 844-434-4210; Email: Participate-In-This-Study1@its.jnj.com

Study Locations

• United States
  • Florida
    • Sarasota, Florida, United States, 34232
      • Recruiting
      • Florida Cancer Specialists & Research Institute
  • Michigan
    • Grand Rapids, Michigan, United States, 49546
      • Recruiting
      • START Midwest
  • Utah
    • West Valley City, Utah, United States, 84119
      • Recruiting
      • START Mountain Region

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria:

• a. Histologically confirmed adenocarcinoma of the prostate. Adenocarcinoma with small cell or neuroendocrine features is permitted. b. Measurable or evaluable disease (metastatic prostate cancer) based on computed tomography (CT), magnetic resonance imaging (MRI), or bone scan. Prior treatment with at least 1 prior novel androgen receptor (AR)-targeted therapy. c. Serum prostate-specific antigen (PSA) value greater than or equal to (>=) 2 nanograms per milliliters (ng/mL). d. Prior orchiectomy or medical castration; or, for participants who have not undergone orchiectomy, must be receiving ongoing androgen deprivation therapy (ADT) with a gonadotropin releasing hormone (GnRH) analog (agonist or antagonist) prior to the first dose of trial drug and must continue this therapy throughout the treatment phase; e. Castrate levels of serum testosterone as defined in the protocol, prior to the first dose of trial intervention; f. Progressive metastatic disease following their most recent line of therapy. Disease progression will be defined by at least one of the following: PSA progression, radiographic progression according to response evaluation criteria in solid tumors (RECIST v1.1), or progressive bone disease according to prostate cancer working group 3 (PCWG3) criteria
• Eastern cooperative oncology group (ECOG) performance status of 0 or 1
• Agree to all of the following during the trial and for 6 months after the last dose of trial drug: a. Use a highly effective method of contraception; b. Wear a condom when engaging in any activity that allows for passage of ejaculate to another person; c. Not to donate sperm or freeze for future use for the purpose of reproduction; d. Not plan to father a child. In addition, the participant should be advised of the benefit for a female partner to use a highly effective method of contraception
• Sign an informed consent form (ICF) indicating that the participant understands the purpose of, and procedures required for, the trial and is willing to participate in the trial

Exclusion criteria:

• Active central nervous system (CNS) involvement
• Toxicity related to prior anticancer therapy that has not returned to Grade less than or equal to (<=) 1 or baseline levels
• External beam radiation therapy to soft tissue lesions within 14 days prior to start of trial intervention
• History of clinically significant cardiovascular disease within 6 months prior to signing informed consent
• History of solid organ or bone marrow transplantation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: JNJ-98768111; Participants in Part 1 of the study will receive escalating doses of JNJ-98768111 to identify the putative recommended phase 2 dose (pRP2D) regimen(s). Participants in Part 2 of the study will receive JNJ-98768111 at the pRP2D regimen(s) determined in Part 1.	Drug: JNJ-98768111; JNJ-98768111 will be administered intravenously.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants with Adverse Events (AEs)	An AE is any untoward medical occurrence in a clinical trial participant administered a pharmaceutical (investigational or non investigational) product. An AE does not necessarily have a causal relationship with the treatment.	Up to approximately 2 years 7 months
Part 1: Number of Participants with Dose-Limiting Toxicities (DLT)	High grade hematologic or non-hematologic toxicities with exceptions and/or toxicities leading to treatment discontinuation will be regarded as DLT. Other DLT criteria includes any related toxicity resulting in permanent treatment discontinuation or a delay in dose administration greater than (>)14 days and any death not clearly due to the underlying disease or non-trial intervention-related causes.	From first administration of trial intervention to the pre-dose assessment of the second cycle (up to approximately 2 years and 7 months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum Observed Concentration (Cmax) of JNJ-98768111	Cmax of JNJ-98768111 will be reported.	Up to approximately 2 years 7 months
Trough Concentration (Ctrough) of JNJ-98768111	Ctrough of JNJ-98768111 will be reported.	Up to approximately 2 years 7 months
Time to Maximum Observed Concentration (Tmax) of JNJ-98768111	Tmax of JNJ-98768111 will be reported.	Up to approximately 2 years 7 months
Area Under the Concentration-Time Curve from Time 0 to End of Dosing Interval (AUC [0-tau]) of JNJ-98768111	AUC0-tau of JNJ-98768111 will be reported.	Up to approximately 2 years 7 months
Accumulation Ratio of JNJ-98768111	Accumulation Ratio (RA) is calculated as area under the plasma concentration-time curve from time zero to 24 hours (AUC [0-24]) value at steady state divided by AUC (0-24) value after first dose.	Up to approximately 2 years 7 months
Number of Participants With Anti-Drug Antibodies (ADAs) to JNJ-98768111	Number of participants with antibodies to JNJ-98768111 will be reported.	Up to approximately 2 years 7 months
Objective Response Rate (ORR)	ORR is defined as the percentage of participants with measurable disease who have a partial response (PR) or better without evidence of bone progression according to prostate cancer working group 3 (PCWG3).	Up to approximately 2 years 7 months
Radiographic Progression-Free Survival (rPFS)	rPFS is defined as the time from the date of first dose until the date of objective disease progression or death, whichever comes first.	Up to approximately 2 years 7 months
Prostate-Specific Antigen (PSA) Response	PSA response rate is defined as the percentage of participants with a decline in PSA of 50% or more from baseline which is sustained for greater than or equal to (>=) 3 weeks.	Up to approximately 2 years 7 months
Duration of Response (DOR)	DOR will be calculated among responders (PR or better) from the date of initial documentation of a 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.	Up to approximately 2 years 7 months

Collaborators and Investigators

• Sponsor: Janssen Research & Development, LLC
• Investigators: Study Director: Janssen Research & Development LLC Clinical Trial, Janssen Research & Development, LLC

Study record dates

Study Major Dates

• Study Start (Actual): August 5, 2026
• Primary Completion (Estimated): March 16, 2029
• Study Completion (Estimated): March 16, 2029

Study Registration Dates

• First Submitted: July 31, 2026
• First Submitted That Met QC Criteria: July 31, 2026
• First Posted (Actual): August 5, 2026

Study Record Updates

• Last Update Posted (Actual): August 31, 2026
• Last Update Submitted That Met QC Criteria: August 27, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Prostatic Diseases; Male Urogenital Diseases; Prostatic Neoplasms
• Other Study ID Numbers: 98768111PCR1001; 2026-525894-37-00 (Registry Identifier: EUCT number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No