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

July 2, 2026 updated by: Janssen Research & Development, LLC

A Phase 1 Study of JNJ-78278343, a T-Cell-Redirecting Agent Targeting Human Kallikrein 2 (KLK2), for Advanced Prostate Cancer

The purpose of this study is to determine the recommended phase 2 dose(s) (RP2Ds) of JNJ-78278343 in Part 1 (Dose Escalation) and the safety at the RP2Ds in Part 2 (Dose Expansion).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

JNJ-78278343 is a humanized immunoglobulin (Ig)G1-based bispecific antibody designed to direct T lymphocytes (T cells) to human kallikrein 2 (hK2or KLK2) positive target tumor cells. One arm of JNJ-78278343 binds to the cluster of differentiation (CD)3 receptor complex present on T cells and the other arm binds to KLK2 present on target tumor cells leading to the activation of the T cells and T-cell-mediated lysis of the KLK2 bearing tumor cells. JNJ-78278343 is being developed for the treatment of metastatic castration-resistant prostate cancer (mCRPC). KLK2 expression is highly restricted in normal tissues and highly enriched in prostate adenocarcinoma and its expression is mostly maintained throughout disease progression, making KLK2 an attractive target for therapy. This study will be conducted in 2 phases: a Screening Phase (up to 30 days), a Treatment Phase (start of study drug administration) with an end of treatment (EOT) visit (up to 30 plus 14 days after last dose of study drug or prior to the start of a new anticancer therapy), whichever comes first). The total duration of the study is up to 1 year and 10 months. Safety assessment will include adverse events (AEs) including dose-limiting toxicity (DLT), serious adverse events (SAEs), physical examination, vital signs, electrocardiogram, clinical safety laboratory assessments, Eastern Cooperative Oncology Group (ECOG) performance status, and neurologic examination.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
216

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
      • Beijing, China, 100191
        • Peking University Third Hospital
      • Chongqing, China, 400030
        • Chongqing University Cancer Hospital
      • Guangzhou, China, 510710
        • Sun Yat Sen University Cancer Center
      • Wenzhou, China, 325399
        • First Affiliated Hospital Of Wenzhou Medical College
  • France
      • Lyon, France, 69373
        • Centre Léon Bérard
      • Marseille, France, 13005
        • Aphm Hopital Timone
      • Villejuif, France, 94800
        • Institut Gustave Roussy
  • Japan
      • Kashiwa, Japan, 277 8577
        • National Cancer Center Hospital East
      • Yokohama, Japan, 232 0024
        • Yokohama City University Medical Center
  • Netherlands
      • Amsterdam, Netherlands, 1066 CX
        • Antoni van Leeuwenhoek
      • Rotterdam, Netherlands, 3015 GD
        • Erasmus MC
  • Spain
      • Madrid, Spain, 28040
        • Hosp Univ Fund Jimenez Diaz
      • Madrid, Spain, 28050
        • Hosp Univ Hm Sanchinarro
      • Málaga, Spain, 29010
        • Hosp Virgen de La Victoria
  • United States
    • New York
      • New York, New York, United States, 10065
        • Memorial Sloan Kettering Cancer Center
      • New York, New York, United States, 10032
        • Columbia University Medical Center Herbert Irving Pavilion
    • Washington
      • Seattle, Washington, United States, 98195-9472
        • University of Washington

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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

Exclusion Criteria:

Disease conditions

  • Active central nervous system (CNS) involvement
  • 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
  • Active infection
  • Major diseases of heart and blood vessels within 6 months prior to the first dose of study drug
  • Clinically significant lung diseases
  • Active or chronic hepatitis B or hepatitis C infection
  • Known positive test result for human immunodeficiency virus (unless stable on antiretroviral therapy with undetectable viral load)
  • Any serious underlying medical conditions or other issue that would impair the ability of the participant to receive or tolerate the planned treatment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: JNJ-78278343
Participants will receive JNJ-78278343. The dose levels will be escalated based on the dose limiting toxicities (DLT) evaluation by the study evaluation team (SET) in Part 1 (dose escalation). In Part 2 (dose expansion), participants will receive JNJ-78278343 at recommended phase 2 dose (RP2D) as determined in Part 1. Participants who are still on study treatment (i.e., who are in Treatment Phase) at the time of the long term extension (LTE) will continue to receive study treatment until they reach a reason for discontinuation of treatment or until further notification by the sponsor of a different means for continued supply of study treatment, whichever occurs first.
Drug: JNJ-78278343
JNJ-78278343 will be administered.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Part 1 and 2: Number of Participants With Adverse Events (AEs)
Time Frame: Up to 1 year and 10 months
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.
Up to 1 year and 10 months
Part 1 and 2: Number of Participants With AEs by Severity
Time Frame: Up to 1 year and 10 months
Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 5.0. 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. Cytokine release syndrome (CRS) and immune effector cell associated neurotoxicity syndrome (ICANS) will be graded according to the American Society for Transplantation and Cellular Therapy (ASTCT) guidelines.
Up to 1 year and 10 months
Part 1: Number of Participants With Dose-Limiting Toxicity (DLT)
Time Frame: Up to 1 year and 10 months
Number of participants with DLT will be reported. The DLTs are specific adverse events and are defined as any of the following: high grade non-hematologic toxicity, or hematologic toxicity.
Up to 1 year and 10 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Serum Concentration of JNJ-78278343
Time Frame: Up to 1 year and 10 months
Serum concentrations of JNJ-78278343 will be determined.
Up to 1 year and 10 months
Systemic Cytokine Concentrations
Time Frame: Up to 1 year and 10 months
Cytokine concentrations will be determined for biomarker assessment.
Up to 1 year and 10 months
Serum Prostate Specific Antigen (PSA) Concentration
Time Frame: Up to 1 year and 10 months
Serum PSA concentration will be measured.
Up to 1 year and 10 months
Number of Participants With Anti-JNJ-78278343 Antibodies
Time Frame: Up to 1 year and 10 months
Serum samples will be analyzed for the detection of anti-JNJ-78278343 antibodies using a validated assay method.
Up to 1 year and 10 months
Objective Response Rate (ORR)
Time Frame: Up to 1 year and 10 months
ORR is defined as the percentage of participants who have a partial response (PR) or better according to the response evaluation criteria in solid tumors (RECIST) version 1.1 response criteria without evidence of bone progression according to prostate cancer working group 3 (PCWG3).
Up to 1 year and 10 months
PSA Response Rate
Time Frame: Up to 1 year and 10 months
PSA response rate is defined as the percentage of participants with a decline of PSA of 50 percent (%) or more from baseline. The maximum reduction from baseline in PSA will also be calculated during the treatment.
Up to 1 year and 10 months
Duration of Response (DOR)
Time Frame: Up to 1 year and 10 months
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 RECIST version 1.1 response criteria, or death due to any cause, whichever occurs first.
Up to 1 year and 10 months
Radiographic Progression-free Survival (rPFS)
Time Frame: Up to 1 year and 10 months
rPFS is defined as time from the date of first dose of JNJ-78278343 until the date of objective disease progression or death, whichever comes first.
Up to 1 year and 10 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Janssen Research & Development, LLC

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Janssen Research & Development, LLC Clinical Trial, Janssen Research & Development, LLC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 13, 2021

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 20, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 20, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 24, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 6, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CR108958
  • 2020-005970-83 (EudraCT Number)
  • 78278343PCR1001 (Other Identifier: Janssen Research & Development, LLC)
  • 2023-506585-31-00 (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 www.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

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings