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Taking people in Puerto RicoPhase 3

Tests pasritamig with or without JNJ-87189401 in advanced prostate cancer

Tests pasritamig, with or without another drug, in men with advanced prostate cancer.

Key facts

Who runs it
Janssen Research & Development, LLC
Where
Rio Piedras and San Juan, Puerto RicoSee the 2 sitesAlso in 16 other countries, 175 sites
Registry title
A Study of Pasritamig With or Without JNJ-87189401 Versus Placebo for Late Line Metastatic Castration-resistant Prostate Cancer (mCRPC)
Status
Recruiting
Phase
Phase 3
People taking part
1,203 people, planned
Started
2 Sept 2025
Expected to end
18 Aug 2028
Type of study
Interventional, 5 groupsOne group gets a placebo (a dummy treatment), for comparison.
Treatments tested
  • Pasritamig
  • Placebo
  • Best Supportive Care (BSC)
  • JNJ-87189401
Record updated
3 November 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for men with prostate cancer that has spread and no longer responds to hormone therapy, after other standard treatments have been tried.

Age
18 years or older
Sex
Men only
Disease stage
Prostate adenocarcinoma that has spread to bone and/or lymph nodes and no longer responds to hormone therapy (mCRPC). No spread to organs such as the liver or lungs (visceral disease). PSA of 2 ng/mL or more at screening.
Earlier treatment
Must have had the life-prolonging treatments they can have: progressed on at least 1 androgen-receptor pathway inhibitor, at least 2 taxane-based regimens (with exceptions), PSMA-targeted lutetium therapy (with exceptions), and a PARP inhibitor if they have a known BRCA mutation. Must have had orchiectomy or be on ongoing hormone-lowering treatment (ADT). Cannot have had prior CD3-directed therapy.
Biomarker or test result
PSA of 2 ng/mL or more at screening.

Main reasons for not taking part

  • Blood clot in a vein within 1 month before the first dose
  • Active autoimmune disease needing immune-suppressing drugs in the past 12 months
  • Fever of 38ºC or more, or an infection needing treatment, within 7 days before randomization
  • Heart attack, severe angina, stroke or heart failure (class II to IV) within 6 months
  • Prior treatment with any CD3-directed therapy

The registry criteria, word for word

Show all 21 criteriaShow less

Who can take part

  • Histologically confirmed adenocarcinoma of the prostate
  • Metastatic castration-resistant prostate cancer (mCRPC): Disease that is metastatic either to bone, any lymph node, or both without clear evidence of other metastatic sites at the time of screening by conventional imaging with computed tomography (CT) or magnetic resonance imaging (MRI) (chest, abdomen, and pelvis) and 99m\^Tc bone scan. Visceral disease is not allowed
  • PSA greater than or equal to (≥) 2 nanogram per milliliter (ng/mL) at screening
  • In the opinion of the investigator, the next best treatment option is a clinical trial
  • Participants are required to have had all life-prolonging therapies for which they are clinically eligible in the opinion of the investigator and to which they have access. Prior therapies could have been given in any disease setting (not limited to mCRPC). In particular, prior treatment specifications include receipt of the following:; Androgen-receptor pathway inhibitor (ARPI): Must have progressed on at least 1 ARPI and unlikely to benefit from retreatment with another ARPI; Taxanes: Required to have received at least 2 previous taxane-based regimens. If a participant has received only 1 taxane regimen, the participant is eligible if:
  • Cabazitaxel is not available
  • The participant's physician deems the participant unsuitable to receive a second taxane regimen due to toxicity risk or prior intolerance Note: a taxane-based regimen consists of at least 2 cycles of a taxane (either as a single agent or in combination with other therapies) administered within the same 2-month period; Radioligand therapy: Required to have been previously treated with at least 1 dose of Prostate-specific membrane antigen (PSMA)-targeted lutetium radioligand therapy (eg, lutetium Lu-177 vipivotide tetraxetan), unless one of the following applies:
  • PSMA-targeted lutetium radioligand therapy is unavailable, not accessible, or not clinically indicated
  • The participant's physician deems the participant unsuitable to receive PSMA-targeted lutetium radioligand therapy; Polyadenosine diphosphate-ribose polymerase inhibitors (PARPi): Required to have been previously treated with PARPi, if the participant has a known germline or somatic BRCA mutation and treatment is available
  • Prior orchiectomy or medical castration (receiving ongoing ADT with a GnRH analog [agonist or antagonist]) prior to the first dose of study treatment and must continue this therapy throughout the treatment phase
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
  • Participants are eligible if they have the following values:
  • eGFR ≥ 40 milliliters per minute (mL/min) B) Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) less than or equal to (≤) 3 times the Upper Limit of Normal (ULN) C) Total bilirubin <1.5 times ULN D) Absolute neutrophil count (ANC) ≥ 1.0x10\^9/per liter (L) E) Hemoglobin ≥ 8.0 grams per deciliter (g/dL) F) Platelet count ≥ 75x10\^9/L

Who cannot take part

  • Venous thromboembolic events within 1 month prior to the first dose of study treatment; uncomplicated (Grade ≤ 2) deep vein thrombosis is not exclusionary
  • Participants with Grade 1 or higher fever (≥38ºC) or active infection requiring systemic treatment within 7 days prior to randomization are ineligible. Participants must be afebrile (<38ºC) at the time of study treatment dosing unless approved by medical monitor
  • Prior or concurrent second malignancy (other than the disease under study) for which natural history or treatment could likely interfere with any study endpoints of safety or the efficacy of the study treatment(s)
  • Any of the following within 6 months prior to first dose of study treatment:
  • Prior treatment with any CD3-directed therapy
  • Active autoimmune disease within the past 12 months that requires systemic immunosuppressive medications (eg, chronic corticosteroid, methotrexate, or tacrolimus)
  • Myocardial infarction B) Severe or unstable angina C) Clinically significant ventricular arrhythmias D) Congestive heart failure (New York Heart Association class II to IV) E) Transient ischemic attack F) Cerebrovascular accident
  • Clinically significant pulmonary compromise, particularly a requirement for supplemental oxygen use (>2 liters per minute (L/min) by nasal cannula) to maintain adequate oxygenation

Where in Puerto Rico

Also in 16 other countries, 175 sites

  • Pan American Center for Oncology Trials LLCRio Piedras, Puerto RicoTaking people
  • Puerto Rico Medical Research CenterSan Juan, Puerto RicoTaking people

About the trial

What the trial wants to find out

The purpose of this study is to evaluate the overall survival (length of time from the start of study to date of death from any cause) for pasritamig (JNJ-78278343) in Part 1 in combination with best supportive care (BSC) and in Part 2 with JNJ-87189401+BSC as compared to placebo with BSC in participants with metastatic castration-resistant prostate cancer (mCRPC; a stage of cancer that has spread beyond the prostate gland and is no longer responding to hormone therapies).

The 5 groups in the trial

  • Part 1: Pasritamig+Best Supportive Care (BSC)Treatment being tested

    Participants in Part 1 will receive 2 step-up doses of pasritamig intravenously (IV) followed by the target dose. Participants will receive study treatment until confirmed progressive disease, death, intolerable toxicity, withdrawal of consent, or end of the study, whichever occurs first. All participants may receive BSC (defined as palliative external beam radiation, low dose steroids, pain medication, bone sparing agents, and needed palliative procedures) at the discretion of the physician.

    Treatment: Pasritamig and Best Supportive Care (BSC)

  • Part 1: Placebo+BSCPlacebo, for comparison

    Participants in Part 1 will receive 2 step-up doses of placebo IV followed by the target dose. Participants will receive study treatment until confirmed progressive disease, death, intolerable toxicity, withdrawal of consent, or end of the study, whichever occurs first. All participants may receive BSC (defined as palliative external beam radiation, low dose steroids, pain medication, bone sparing agents, and needed palliative procedures) at the discretion of the physician.

    Treatment: Placebo and Best Supportive Care (BSC)

  • Part 2: Pasritamig+BSCTreatment being tested

    Participants in Part 2 will receive 2 step-up doses of pasritamig IV followed by the target dose. Participants will receive study treatment until confirmed progressive disease, death, intolerable toxicity, withdrawal of consent, or end of the study, whichever occurs first. All participants may receive BSC (defined as palliative external beam radiation, low dose steroids, pain medication, bone sparing agents, and needed palliative procedures) at the discretion of the physician.

    Treatment: Pasritamig and Best Supportive Care (BSC)

  • Part 2: Pasritamig+JNJ-87189401+BSCTreatment being tested

    Participants in Part 2 will receive 2 step-up doses of pasritamig IV followed by the target dose. JNJ-87189401 will be administered with the first target dose of pasritamig. Participants will receive study treatment until confirmed progressive disease, death, intolerable toxicity, withdrawal of consent, or end of the study, whichever occurs first. All participants may receive BSC (defined as palliative external beam radiation, low dose steroids, pain medication, bone sparing agents, and needed palliative procedures) at the discretion of the physician.

    Treatment: Pasritamig, Best Supportive Care (BSC), and JNJ-87189401

  • Part 2: Placebo +BSCPlacebo, for comparison

    Participants in Part 2 will receive 2 step-up doses of placebo IV followed by the target dose. Participants will receive study treatment until confirmed progressive disease, death, intolerable toxicity, withdrawal of consent, or end of the study, whichever occurs first. All participants may receive BSC (defined as palliative external beam radiation, low dose steroids, pain medication, bone sparing agents, and needed palliative procedures) at the discretion of the physician.

    Treatment: Placebo and Best Supportive Care (BSC)

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A Phase 3 Randomized, Double-blind, Placebo-controlled Study of Pasritamig (JNJ-78278343), a T Cell Engaging Agent Targeting Human Kallikrein 2, With or Without JNJ-87189401, a PSMA-CD28 Costimulatory Agent, Plus Best Supportive Care Versus Best Supportive Care for Late-line Metastatic Castration-resistant Prostate Cancer
Plain-language title
Tests pasritamig with or without JNJ-87189401 in advanced prostate cancerGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 12 November 2026.
Record updated
3 November 2026