A study of Pasritamig (JNJ-78278343) in combination with JNJ-86974680 for treatment of prostate cancer
| ISRCTN | ISRCTN10699447 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN10699447 |
| Integrated Research Application System (IRAS) | 1011799 |
| Protocol serial number | 78278343PBPCR1005 |
| Sponsor | Janssen-Cilag International NV |
| Funder | Janssen Research and Development |
- Submission date
- 16/10/2025
- Registration date
- 20/01/2026
- Last edited
- 20/01/2026
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Cancer
Plain English summary of protocol
Background and study aims
Prostate cancer is a cancer that forms in the prostate, a male reproductive gland found below the bladder. Cancer is considered “advanced” if it spreads extensively to other parts of the body. Although treatments are available, they do not cure advanced prostate cancer. Over time, the disease gets worse and progresses to metastatic castration-resistant prostate cancer (mCRPC; prostate cancer that grows despite low levels of male hormones), showing the need for better treatment. Pasritamig (JNJ-78278343) is a bispecific antibody (activates T-cells aimed at damaging tumor cells and stopping them from growing), which targets a protein, human kallikrein 2, on tumor cells and cluster of differentiation 3 protein on T-cells (key cell in the immune system). This type of protein recognizes and attaches to 2 different targets. JNJ-86974680 works by blocking a protein called adenosine A2A receptor present on cancer and immune cells. By blocking this protein, the drug helps immune cells (T cells) to stay active and attack the cancer cells more effectively. In this study, researchers want to identify the most suitable dose of Pasritamig and JNJ-86974680 and to find out how safe it is at the recommended dose.
Who can participate?
Patients with histologically confirmed adenocarcinoma of the prostate.
What does the study involve?
The study will be conducted in 2 parts:
1. Dose Finding (Part 1): Participants will receive Pasritamig and JNJ-86974680 to confirm the recommended phase 2 combination dose(s) (RP2CDs).
2. Dose Expansion (Part 2): Participants will receive Pasritamig and JNJ-86974680 at the doses determined in Part 1 to assess safety and anti-tumor activity.
Safety assessments include physical examinations, vital signs, Eastern Cooperative Oncology Group (ECOG; how well participants can take care of themselves) performance status,
clinical laboratory tests and electrocardiogram (ECG; test to record heart activity). All side effects will be recorded until the study ends (around 1 year 2 months).
What are the possible benefits and risks of participating?
Participants may not receive any benefit from taking part in this study, but the information that is learned from the study may help people with advanced prostate cancer in the future. This is a first-in-human study, which means that Pasritamig (JNJ-78278343) with JNJ-95298177 in combination have not been given to people before, although each of these drugs has been given by itself to participants with prostate cancer.
The expected risks for Pasritamig based on how the drug works and results from clinical studies are listed: cytokine release syndrome (inflammation condition that may occur after treatment with some types of immunotherapy), neurological side effects that may include headaches, changes in mental status, or seizures, and systemic administration-related reaction or infusion related reactions, which can include chills, low blood pressure, or feeling short of breath after the drug infusion. For participants with residual prostate or local tumour tissue, prostatitis (inflammation in the prostate) is possible.
The expected risks for JNJ-86974680 based on how the drug works and results from clinical studies are listed: increased
nausea (feeling like vomiting) and vomiting.
*liver enzymes, which are substances in the blood
The participant information sheet and informed consent form, which will be signed by every participant agreeing to take part in the study, include a detailed section outlining the risks of participating in the study. Participants may have none, some, or all of the possible side effects listed, and they may be mild, moderate, or severe. To minimise the risk associated with taking part, participants are frequently reviewed for any side effects and other medical events. If they have any side effects or are worried about them, or have any new or unusual symptoms, participants will be encouraged to talk with their study doctor. The study doctor will also be looking out for side effects and will provide appropriate medical care. There may also be side effects that the researchers do not expect or do not know about and that may be serious. Many side effects go away shortly after the intervention ends. However, sometimes side effects can be serious, long-lasting, or permanent.
If a severe side effect or reaction occurs, the study doctor may need to stop the procedure. The study doctor will discuss the best way of managing any side effects with participants. There is always a chance that an unexpected or serious side effect may happen. This can happen to people who take this or any other drug.
Where is the study run from?
Janssen-Cilag International NV
When is the study starting and how long is it expected to run for?
January 2026 to June 2028.
Who is funding the study?
Janssen-Cilag International NV
Who is the main contact?
janssenukregistryqueries@its.jnj.com
Contact information
Scientific
-
-
-
United Kingdom
| Phone | +44 (0)800 731 8450, (0)1494 567 444 |
|---|---|
| medinfo@its.jnj.com |
Principal investigator
UK Chief Investigator
15 Cotswold Road
Sutton
SM2 5NG
United Kingdom
| Phone | +44 208 722 4028 |
|---|---|
| johann.debono@icr.ac.uk |
Public
500- 100 Holmers Farm Way
High Wycombe
HP12 4EG
United Kingdom
| janssenukregistryqueries@its.jnj.com |
Study information
| Primary study design | Interventional | |
|---|---|---|
| Allocation | Non-randomized controlled trial | |
| Masking | Open (masking not used) | |
| Control | Uncontrolled | |
| Assignment | Single | |
| Purpose | Treatment | |
| Scientific title | A phase 1b study of Pasritamig (JNJ-78278343), a T-cell redirecting agent targeting human kallikrein 2 (KLK2), in combination with JNJ-86974680, an A2a receptor (A2aR) antagonist, for prostate cancer | |
| Study objectives | 1.1.Main objectives • Part 1 (Dose finding): To find out the most suitable dose (recommended phase 2 combination dose[s] [RP2CDs]) of Pasritamig (JNJ-78278343) and JNJ-86974680. • Part 2 (Dose expansion): To find out how safe Pasritamig and JNJ-86974680 are at the recommended dose(s). 1.2.Secondary objectives • To assess the preliminary antitumor (cancer-fighting) activity. • To evaluate the pharmacokinetics* of Pasritamig and JNJ-86974680. *Process by which drug gets absorbed, distributed in the body, and excreted. • To evaluate immunogenicity (immune response against the drug) of Pasritamig. | |
| Ethics approval(s) |
Approved 16/12/2025, North West - Haydock Research Ethics Committee (2 Redman Place, Stratford, London, E20 1JQ, United Kingdom; -; haydock.rec@hra.nhs.uk), ref: 25/NW/0333 | |
| Health condition(s) or problem(s) studied | Prostate cancer | |
| Intervention | The study will be conducted in 2 Parts: Part 1: Dose Finding, Participants will receive pasritamig in combination with JNJ-86974680 to determine the recommended phase 2 combination dose (RP2CD) regimen. Part 2: Dose Expansion Participants will receive pasritamig in combination with JNJ-86974680 at the RP2CD as determined in Part 1 of the study to confirm the safety and anti-tumor activity. Pasritamig will be administered intravenously & JNJ-86974680 will be administered orally. Safety assessments include physical examinations, vital signs, Eastern Cooperative Oncology Group (ECOG; how well participants can take care of themselves) performance status, clinical laboratory tests and electrocardiogram (ECG; test to record heart activity). All side effects will be recorded until the study ends (around 1 year and 2 months). | |
| Intervention type | Drug | |
| Phase | Phase I | |
| Drug / device / biological / vaccine name(s) | JNJ-78278343, JNJ-86974680 | |
| Primary outcome measure(s) |
1. Number of Participants With Adverse Events (AEs) by Severity | |
| Key secondary outcome measure(s) |
1. Objective Response Rate (ORR). 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). [Time Frame: Up to 1 year 2 months] | |
| Completion date | 30/06/2028 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 110 Years |
| Sex | Male |
| Target sample size at registration | 40 |
| Key inclusion criteria | 1. 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 NEmarker positivity) are allowed. 2. Metastatic castration-resistant prostate cancer (mCRPC) that is metastatic either to bone, any lymph node, or both without clear evidence of metastasis to visceral organs. Local-regional invasion (rectum, bladder) and bone disease with soft tissue component can be included 3. Prior orchiectomy or medical castration (for example, 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) 4. Prostate-specific antigen (PSA) greater than or equal to (>=) 2 nanograms per milliliters (ng/mL) at screening 5. Measurable or evaluable disease 6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 |
| Key exclusion criteria | 1. Toxicity related to prior anticancer therapy that has not returned to grade less than or equal to (<=) 1 or baseline levels (except for alopecia, neuropathy [Grade 2] and vitiligo) 2. Known allergies, hypersensitivity, or intolerance to any of the components (for example, excipients) of pasritamig or JNJ-86974680 3. Active infection or condition that requires treatment with systemic antibiotics within 7 days prior to the first dose of study treatment. Antibiotic or antiviral prophylaxis is allowed 4. Have leptomeningeal disease or brain metastases, except participants with definitively, locally treated brain metastases that are clinically stable and asymptomatic >2 weeks, and who are off corticosteroid treatment for at least 2 weeks prior to first dose of study treatment 5. 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 |
| Date of first enrolment | 14/01/2026 |
| Date of final enrolment | 22/05/2026 |
Locations
Countries of recruitment
- United Kingdom
- England
- United States of America
Study participating centres
Withington
Manchester
M20 4BX
England
Sutton
SM2 5PT
England
Sarasota
34232
United States of America
New York
10032
United States of America
Cleveland
44106
United States of America
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request, Stored in non-publicly available repository |
| IPD sharing plan | The data sharing policy of the Janssen Pharmaceutical Companies of Johnson and Johnson is available at www.janssen.com/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through the Yale Open Data Access (YODA) Project site at yoda.yale.edu. |
Editorial Notes
24/12/2025: ISRCTN received notification of combined HRA/MHRA approval for this trial on 24/12/2025.
16/10/2025: Trial's existence confirmed by NHS HRA.
