RecruitingPhase IIIInterventional

A phase 3 randomized double-blinded, placebo-controlled study of JNJ-78278343, T-Cell redirecting agent targeting Human Kallikrein 2 with best supportive care (BSC) versus placebo with BSC for metastatic castration-resistant prostate cancer_KLK2 comPAS_78278343PCR3001

This study is for men with advanced prostate cancer that has spread beyond the prostate and is no longer responding to hormone treatment (called metastatic castration-resistant prostate cancer, or mCRPC). The research aims to see if a new drug, pasritamig, can help men live longer when given alongside their usual care. Pasritamig is designed to help the body's own immune system fight cancer cells. Participants will be randomly given either pasritamig or a dummy drug (placebo), in addition to their existing prostate cancer treatment. The study also monitors side effects and general health over several years. It's hoped this research could lead to better treatments for men with mCRPC in the future.

At a glance

Status

Recruiting

Phase

Phase III

Sponsor

Janssen-Cilag International NV

Enrolment target

663

Start

14 Oct 2025

Estimated completion

14 Jun 2027

Metastatic Castration-resistant Prostate Cancer

What is this study about?

Prostate cancer starts in the prostate gland, a small gland in men that sits below the bladder. If this cancer spreads to other parts of the body, it's called 'metastatic.' When it also stops responding to common hormone treatments, doctors call it 'metastatic castration-resistant prostate cancer' (mCRPC). While there are treatments available, the cancer can eventually get worse over time. This means doctors are always looking for new and better ways to treat it, especially treatments that are easier to cope with.

This study is looking at a new medicine called pasritamig. Pasritamig is a special type of protein designed to recognise and attach to cancer cells. It also connects to your body's immune cells (called T-cells). By doing this, pasritamig acts like a bridge, bringing your immune system closer to the cancer cells and encouraging it to fight and stop the cancer from growing. The main goal of this study is to find out if taking pasritamig, along with your usual supportive care, helps men with mCRPC live longer than those who receive a dummy drug (placebo) with their usual care.

This research is in 'Phase 3,' which means it's a larger study testing whether a new treatment is effective and safe compared to current options. The study will last for about four and a half years, during which participants' health will be closely monitored. This includes checking for any good or bad effects of the treatment and making sure participants are as comfortable as possible.

Key takeaways

This study is for advanced prostate cancer that has spread and isn't responding to hormone therapy.
It tests a new drug, pasritamig, that aims to use your immune system to fight cancer.
Participation involves receiving either pasritamig or a dummy drug, plus your usual care.
Your health will be closely monitored for several years.
There are potential benefits and risks, which will be fully explained to you.
You won't have to pay to participate, and travel costs may be reimbursed.

Who may be eligible?

To join this study, you must be at least 18 years old and have a specific type of prostate cancer called metastatic castration-resistant prostate cancer (mCRPC). This means your prostate cancer has spread to other parts of your body, such as bones or lymph nodes, and is no longer being controlled by hormone therapy. You will need to have had specific previous treatments for your prostate cancer that your doctor can discuss with you.

An important part of being in the study is that your general health and how well you can look after yourself will be assessed. You'll need to be in a reasonable state of health, as determined by a standard health check. You must also either have had surgery to remove your testicles in the past, or be currently receiving regular hormone injections for your prostate cancer, and you will need to continue this treatment throughout the study.

Your doctor will decide if this study is potentially the best next treatment option for you, considering all other available treatments you might be eligible for. There are also specific requirements about your blood test results (for example, kidney and liver function) that your study doctor will check to make sure the treatment is safe for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years or older?
Do you have prostate cancer that has spread?
Is your prostate cancer no longer responding to hormone therapy?
Are you currently receiving hormone therapy OR have you had surgery to remove your testicles?
Is your general health reasonably good (your doctor will check this)?
Have you discussed this study with your doctor and reviewed other available treatments?

Answer every question to see your result.

What does participation involve?

If you decide to take part, the study will involve several phases. First, there's a 'screening' phase, which lasts up to 28 days. During this time, you'll have tests and checks to make sure the study is right for you. If you qualify, you'll then enter the 'treatment' phase.

In the treatment phase, you'll be randomly assigned to one of two groups: two out of three participants will receive pasritamig, and one out of three will receive a 'placebo' (a dummy drug that looks like pasritamig but contains no active medicine). This random assignment helps ensure the study results are fair. Both groups will also receive 'best supportive care,' which is your usual medical care to help manage your symptoms and well-being. Neither you nor your study doctor will know which treatment you are receiving until the end of the study.

Throughout the study, your health will be regularly monitored. This includes checking for any side effects, taking your vital signs (like blood pressure), and having regular blood tests. After your last dose of treatment, you'll have an 'End of Treatment' visit and then enter a 'Post-Treatment Follow-Up' phase. During this follow-up, your health will be checked every 12 weeks until the end of the study, which could be up to 4 years and 8 months in total.

Potential risks and benefits

There's no guarantee that you'll directly benefit from taking part in this study, especially if you are in the placebo group. However, based on earlier research, there's a scientific theory that pasritamig might help treat your prostate cancer. Even if you don't receive pasritamig, some people find that the regular medical checks and close monitoring during a study are beneficial. Importantly, participating could help doctors learn more about mCRPC, which might benefit other patients in the future. Like all medicines, pasritamig can have side effects. These can range from mild to severe, and in very rare cases, could be life-threatening. Common side effects can include reactions during or after an intravenous (IV) drip (like a fever or rash), an overactive immune response (called cytokine release syndrome), and tiredness. Other potential side effects include brain-related issues, inflammation of the prostate, sickness, diarrhoea, anaemia, or headaches. You will receive detailed information about all known risks before you agree to participate. The study team will review you frequently for any side effects, and you'll be encouraged to report anything unusual so you can receive appropriate care. If new information about pasritamig's risks becomes available during the study, your doctor will tell you right away. You are free to withdraw from the study at any time, for any reason, without it affecting your future medical care.

Locations (5)

University College London Hospitals NHS Foundation Trust
City only
London, England
The Royal Marsden NHS Foundation Trust
City only
London, England
The Christie
Approximate
Manchester, England
Belfast City Hospital
Approximate
Belfast, Northern Ireland
University Hospitals Birmingham NHS Foundation Trust
City only
Birmingham, England

Common questions

What is 'metastatic castration-resistant prostate cancer'?

It's an advanced prostate cancer that has spread to other parts of the body and is no longer responding to standard hormone-blocking treatments.

What is pasritamig?

Pasritamig is a new investigational drug designed to help your body's immune system (T-cells) find and attack your prostate cancer cells.

Will I definitely receive the new drug?

Because it's a randomised study, you have a 2 in 3 chance of receiving pasritamig. The other 1 in 3 chance is that you'll receive a placebo (dummy drug).

How long will the study last if I join?

The study itself will run for about 4 years and 8 months, and you'll be involved for that duration, including regular follow-up checks after treatment.

Will I have to pay to be in the study?

No, there are no costs for participating. The study drug and tests are paid for, and you may receive help with travel costs.

How to find out more

Laura Finnan

Official trial record

Always speak to your GP or specialist before deciding to take part in a study.