AuthorisedTherapeutic exploratory (Phase II)Interventional

Randomized Phase II study of multi-peptide vaccination and bispecific PSMAxCD3 antibody treatment in patients with biochemical relapse of prostate cancer

This study is exploring a new treatment approach for men who have previously received treatment for prostate cancer, but whose blood tests now show rising prostate-specific antigen (PSA) levels. This rise is called a biochemical relapse, suggesting tiny amounts of cancer remain, even if they cannot be seen on scans. Researchers are combining two treatments to help the immune system fight the cancer. The first is a multi-peptide vaccine, which teaches immune cells to recognise proteins found on prostate cancer. The second is an antibody called PSMAxCD3, which works like a bridge to bring fighting immune cells directly into contact with cancer cells. The main goal is to find out if this combination can safely slow down or stop cancer growth before it spreads, offering a targeted option that may delay the need for other treatments.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Universitaetsklinikum Tuebingen AöR

Enrolment target

Start

20 Jul 2026

biochemical relapse of prostate cancer

What is this study about?

Prostate cancer is the most common cancer in men in the UK. Many men are successfully treated with surgery or radiotherapy, but sometimes cancer cells remain behind. Doctors monitor this by checking PSA levels in the blood. When PSA levels start creeping back up without any visible tumours on standard scans, doctors call this a 'biochemical relapse'. Finding treatments at this early stage could stop the disease from spreading further.

This trial investigates a combination of two targeted immunotherapies. Immunotherapy works by helping your body's own natural defence system fight disease. The first part is a cancer vaccine made from multiple small proteins (peptides) commonly found on prostate cancer cells. This vaccine acts like a 'wanted poster', training your immune system to spot these specific cells.

The second part is a specialised medicine called a bispecific antibody (PSMAxCD3). This molecule has two ends: one end attaches to a protein on prostate cancer cells (PSMA), while the other end grabs onto a fighting immune cell (CD3). By physically pulling the two together, it helps the immune cell destroy the cancer cell quickly and effectively.

By testing these two treatments together, researchers hope to see if they can clear hidden cancer cells and keep PSA levels down. If successful, this approach could offer an alternative to hormone therapies, which can cause significant long-term side effects.

Key takeaways

Tests a combination of a cancer vaccine and a targeted antibody.
Aimed at men with rising PSA levels after initial prostate cancer treatment.
Works by guiding the immune system to find and destroy hidden cancer cells.
Phase II trial focusing on safety and how well the treatment works.
Participation is completely voluntary and you can stop at any time.

Who may be eligible?

This study is open to adult men aged 18 and over who have been treated for prostate cancer in the past and are now showing rising PSA levels (biochemical relapse). Participants should generally be in good health and able to carry out normal daily activities.

You may not be eligible if your cancer has already spread widely to distant parts of the body (such as your bones or organs) visible on scans, or if you have an active autoimmune condition where your immune system attacks healthy tissue. Men with severe heart conditions or other serious illnesses might also be unable to join, as safety is the top priority.

A doctor on the study team will carry out detailed blood tests and health checks to confirm whether this trial is a safe and suitable option 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.

I am a man aged 18 or older.
I have had previous treatment for prostate cancer (such as surgery or radiotherapy).
My recent blood tests show rising PSA levels.
My cancer has not shown major spread to other parts of my body on scans.
I am well enough to attend regular hospital appointments for treatment and tests.

Answer every question to see your result.

What does participation involve?

Taking part in this study involves regular visits to a specialist hospital clinic. Before starting, you will have baseline health checks, including blood tests and scans. During the treatment period, you will receive the study vaccine as an injection and the antibody treatment through a drip into a vein. Doctors will monitor you closely during and after treatments for any side effects. You will need regular follow-up appointments over several months to check your PSA levels, general health, and immune response. The total study duration typically lasts several months to a year, and your care team will explain the exact schedule before you agree to join.

Potential risks and benefits

Taking part may help slow down or stop your cancer from returning, and the extra monitoring could give you closer contact with cancer specialists. However, there is no guarantee that the treatment will work for everyone. Possible risks include common vaccine reactions like redness, swelling, or soreness at the injection site, as well as fever, tiredness, or flu-like aches. The antibody treatment may cause temporary immune reactions, such as chills or low blood pressure. Your safety is monitored throughout, and you are free to leave the trial at any time without giving a reason and without it affecting your usual NHS care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Germany

Common questions

What does 'biochemical relapse' mean?

It means your PSA blood test level has started to rise again after previous treatment, suggesting cancer cells may still be present, even if they are too small to be seen on scans.

Is the cancer vaccine like a normal flu jab?

No. While it is given as an injection, it does not prevent infections. Instead, it is designed to train your immune system to recognise and fight cancer cells already in your body.

How does the bispecific antibody work?

It acts like a connector. One side hooks onto a protein on the prostate cancer cell, and the other hooks onto your body's immune cells, bringing them together so the immune cell can attack the cancer.

Will taking part cost me anything?

No, the trial treatment and extra tests are provided free of charge. Some trials also help cover travel expenses to and from hospital visits.

Can I leave the study if I change my mind?

Yes, taking part is entirely voluntary. You can withdraw at any time, and your standard medical care will continue as normal.