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Pasritamig versus placebo for late-line metastatic castration-resistant prostate cancer

A Phase 3 Randomized, Double-blind, Placebo-controlled Study of Pasritamig (JNJ-78278343), a T Cell Redirecting Agent Targeting Human Kallikrein 2, + Best Supportive Care Versus Best Supportive Care for Metastatic Castration-resistant Prostate Cancer

Phase 3 Interventional Janssen Research & Development, LLC · NCT07164443

This will test whether pasritamig plus best supportive care helps people with late-line metastatic castration-resistant prostate cancer live longer than placebo plus supportive care.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment663 (estimated)
Ages18 Years and up
SexMale
SponsorJanssen Research & Development, LLC Industry-sponsored
Drugs / interventionsmethotrexate
Locations166 sites (La Jolla, California and 165 other locations)
Trial IDNCT07164443 on ClinicalTrials.gov

What this trial studies

This randomized Phase 3 trial compares pasritamig (JNJ-78278343) plus best supportive care to placebo plus best supportive care in people with metastatic castration-resistant prostate cancer who have progressed after standard therapies. The primary endpoint is overall survival, with participants randomized to receive pasritamig or placebo alongside supportive measures. Eligible participants must have histologically confirmed prostate adenocarcinoma, metastatic disease on conventional imaging, PSA ≥2 ng/mL, and have received all life‑prolonging therapies for which they are eligible. The study is sponsored by Janssen and is being conducted at multiple U.S. cancer centers.

Who should consider this trial

Good fit: Ideal candidates are adults with histologically confirmed prostate adenocarcinoma and metastatic castration-resistant disease (PSA ≥2 ng/mL) who have progressed on prior androgen-receptor pathway inhibitors and have received all available life-prolonging therapies and for whom a clinical trial is the next best option.

Not a fit: Patients with non-adenocarcinoma prostate cancers, those who have not yet received appropriate prior life-prolonging therapies, or those unable to travel to or tolerate investigational treatments are unlikely to benefit from this trial.

Why it matters

Potential benefit: If effective, pasritamig could extend overall survival for patients with late-line mCRPC.

How similar studies have performed: Some other late-line therapies for mCRPC have shown modest survival benefits, but pasritamig is a novel agent and this Phase 3 trial aims to confirm signals seen in earlier studies.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria

* 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
* 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 should 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: Should have received at least 2 previous taxane-based regimens. If a participant has received only 1 taxane regimen, the participant is eligible if:

1. Cabazitaxel is not available
2. 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. Participants who cannot continue taxane therapy because of a documented Grade\>=3 taxane related IRR are eligible for enrollment, even if they received fewer than 2 prior cycles of taxane treatment

Radioligand therapy: Should 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:

1. PSMA-targeted lutetium radioligand therapy is unavailable, not accessible, or not clinically indicated.
2. The participant's physician deems the participant unsuitable to receive PSMA-targeted lutetium radioligand therapy.

Polyadenosine diphosphate-ribose polymerase inhibitors (PARPi): Should 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:

A) eGFR \>= 30 milliliters per minute (mL/min) B) Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) less than or equal to (\<=) 5 times the Upper Limit of Normal (ULN) C) Serum total bilirubin \<= 3 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

Exclusion Criteria

* Venous thromboembolic events within 1 month prior to the first dose of study treatment; uncomplicated (Grade \<= 2) deep vein thrombosis is not exclusionary
* Active autoimmune disease within the past 12 months that requires systemic immunosuppressive medications (eg, chronic corticosteroid, methotrexate, or tacrolimus)
* 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
* Clinically significant pulmonary compromise, particularly a requirement for supplemental oxygen use (\>2 liters per minute (L/min) by nasal cannula) to maintain adequate oxygenation
* 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:

A) 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

\- Prior treatment with any CD3-directed therapy

Where this trial is running

La Jolla, California and 165 other locations

+116 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Metastatic Castration-resistant Prostate Neoplasms
Last reviewed 2026-06-13 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.