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Clinical trial Recruiting at 6 sites Phase 1 Interventional Ages 18 and up Men only

Combination treatment with JNJ-78278343 and JNJ-95298177 for prostate cancer

Official title: A Phase 1b Study of JNJ-78278343, a T-cell Redirecting Agent Targeting Human Kallikrein 2 (KLK2), in Combination With JNJ-95298177, an Antibody Drug Conjugate Targeting Prostate Specific Membrane Antigen, for Prostate Cancer

Run by Janssen Research & Development, LLC · NCT07082920 · Data updated 2026-11-12

This trial tests whether giving two experimental drugs together, JNJ-78278343 and JNJ-95298177, is safe and tolerable for men with metastatic castration-resistant prostate cancer.

More Prostatic Neoplasms trials

Quick facts

PhasePhase 1
Study typeInterventional
Ages18 Years and up
SexMen only
Enrollment140 (estimated)
SponsorJanssen Research & Development, LLC
Industry-sponsored
Drugs / interventionsCAR-T, Chimeric Antigen Receptor
Locations6 sites (Sarasota, Florida and 5 other locations)
StatusRecruiting
StartedJuly 7, 2025
Main results expectedNovember 30, 2027
Study endsDecember 30, 2027
Registry record updatedNovember 3, 2026
Trial IDNCT07082920 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Men with histologically confirmed prostate adenocarcinoma who have metastatic castration-resistant disease, PSA ≥2 ng/mL, measurable or evaluable disease, are on continuous androgen-deprivation therapy, and have ECOG performance status 0 or 1 are ideal candidates.

Probably not a fit

Patients with primary small cell or large cell neuroendocrine prostate cancers, those not meeting the PSA or metastatic criteria, or those with poor performance status are unlikely to be eligible or to benefit from this trial.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This Phase 1, open-label trial has two parts: Part 1 will confirm dose levels to identify a recommended phase 2 combination dose (RP2CD), and Part 2 will expand at that dose to further characterize safety and tolerability in participants with metastatic castration-resistant prostate cancer (mCRPC). Eligible participants have histologically confirmed prostate adenocarcinoma (with certain neuroendocrine-feature exceptions), measurable or evaluable disease, PSA ≥2 ng/mL, and ECOG 0–1 while on continuous androgen-deprivation therapy. Participants receive combination dosing of JNJ-78278343 and JNJ-95298177 with safety monitoring and disease assessments per protocol. The primary goal is to define a tolerable combination dose and characterize adverse events and tolerability in this patient population.

Why it matters

Potential benefit: If successful, the combination could offer a new tolerable treatment option that may help control disease in men with mCRPC.

How similar studies have gone: These specific agents are experimental and while some early-phase combination approaches in prostate cancer have shown mixed signals, direct clinical evidence for this exact combination is limited.

Who can join: the full rules

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Histologically confirmed adenocarcinoma of the prostate. Primary small cell carcinoma, carcinoid tumor, neuroendocrine (NE) carcinoma, or large cell NE carcinoma arising in the prostate are not allowed; however, adenocarcinomas with NE features (for example \[e.g.\], immunohistochemistry \[IHC\] with both androgen receptor \[AR\]- and NE-marker positivity) are allowed
* Must have metastatic castration-resistant prostate cancer (mCRPC)
* PSA must measure at least 2 nanograms per milliliters (ng/mL) at screening
* Measurable or evaluable disease
* Prior orchiectomy or medical castration; or, for participants who have not undergone orchiectomy, must be receiving ongoing androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) analog (agonist or antagonist) prior to the first dose of study drug and must continue this therapy throughout the treatment phase
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

Exclusion criteria:

* Toxicity related to prior anticancer therapy that has not returned to grade less than or equal to (\<=) 1 or baseline levels (except for alopecia and vitiligo)
* Known allergies, hypersensitivity, or intolerance to any of the components (e.g., excipients) of JNJ-78278343, JNJ-95298177, or JNJ-87189401
* Participants with leptomeningeal disease or brain metastases, with the exception of participants with definitively, locally treated brain metastases that are clinically stable and asymptomatic greater than (\>) 2 weeks, and who are off corticosteroid treatment for at least 2 weeks prior to first dose of study treatment
* Treatment with any anti-cancer or investigational agents within 14 days prior to the first dose of study treatment; specific requirements for certain anti-cancer therapies are as follows:

  1. Any T-cell redirecting treatment (e.g., CD3-directed bispecific or Chimeric Antigen Receptor T-cell \[CAR-T\] therapy) within 90 days prior to the first dose of study treatment
  2. Immune checkpoint inhibitors within 6 weeks prior to the first dose of study treatment
  3. Radium (Ra) 223 dichloride within 28 days prior to the first dose of study treatment
  4. Any prior treatment with kallikrein-related peptidase 2 (KLK2)-targeted therapy
  5. Any prior prostate-specific membrane antigen (PSMA)-targeting therapy (that is \[i.e.\], participants who received PSMA-targeting radioconjugates are excluded) \[Parts 2A and 2B only\]. Prior PSMA RLT is allowed in Part 1 and required for Part 2C and Part 2D but last dose must be \>3 months prior to the first dose of study treatment
  6. Any prior antibody drug conjugates (ADCs) with microtubule inhibitor payloads (e.g., auristatins, maytansinoids, tubulysins)
* Any serious underlying medical conditions or other issue that would impair the ability of the participant to receive or tolerate the planned treatment at the investigational site to understand the informed consent, or any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant or that could prevent, limit, or confound the protocol-specified assessments

Where it's running

  • Florida Cancer Specialists
    Sarasota, Florida, United States     Recruiting
  • Columbia University Medical Center
    New York, New York, United States     Recruiting
  • University Hospitals Cleveland Medical Center
    Cleveland, Ohio, United States     Recruiting
  • Fred Hutchinson Cancer Center
    Seattle, Washington, United States     Recruiting
  • The Christie Nhs Foundation Trust
    Manchester, United Kingdom     Recruiting
  • Royal Marsden Hospital (Sutton)
    Sutton, United Kingdom     Recruiting

Study contacts

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
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Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.