AuthorisedTherapeutic confirmatory (Phase III)Interventional

PembroLizumab Adjuvant in patients with early-stage Triple NEgaTive breast cancer with residual disease after neoadjuvant pembrolizumab plus chemotherapy – the multicenter, randomized phase III, pragmatic PLANET trial

This important study, called the PLANET trial, is for people with early-stage triple-negative breast cancer. This type of breast cancer can be more aggressive and often needs strong treatment. Even after initial medication and chemotherapy, some cancer cells might remain. This trial investigates if giving additional treatments, like the drug PembroLizumab (also known as KEYTRUDA) or other anti-cancer drugs, can prevent the cancer from returning. Researchers want to find out which approaches are most effective at stopping the cancer from spreading or coming back (often called 'invasive disease-free survival'). They will also look at how patients feel, their quality of life, and any side effects, to ensure the best possible care.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Het Nederlands Kanker Instituut-Antoni van Leeuwenhoek Ziekenhuis Stichting

Enrolment target

1,000

Start

01 Apr 2026

Triple negative breast cancer

What is this study about?

This study, called PLANET, is exploring better ways to treat a specific type of breast cancer known as triple-negative breast cancer. Doctors usually give treatments like chemotherapy before surgery to shrink the cancer. This is called 'neoadjuvant' treatment. For some people, even after this initial treatment, a small amount of cancer might still be present in the breast or lymph nodes. This study focuses on these individuals, as they might have a higher risk of the cancer coming back.

The main aim of the PLANET trial is to see if giving extra treatment after the initial chemotherapy and surgery can stop the cancer from returning or spreading. They are comparing several different treatment approaches, including a drug called PembroLizumab (you might know it as KEYTRUDA), which works by boosting the body's own immune system to fight cancer, and other established anti-cancer medicines. Researchers want to identify which of these treatments is most effective at preventing the cancer from recurring.

Beyond simply checking if the cancer comes back, the study will also look at how these treatments affect patients' overall health, their quality of life, and any side effects they might experience. This helps doctors understand not just if a treatment works, but how well people tolerate it and if it improves their daily lives. The information gathered from this study will help improve future care for people with triple-negative breast cancer.

Key takeaways

This study is for early-stage triple-negative breast cancer where some cancer remained after initial treatment.
It aims to find better ways to stop breast cancer from returning.
Different treatments, including immunotherapy, are being compared.
Your quality of life and side effects will be closely monitored.
Participation could last several years, including treatment and follow-up.

Who may be eligible?

To be considered for this study, you would typically need to be an adult, aged 18 years or older, with triple-negative breast cancer that was diagnosed at an early stage.

A key requirement for this study is that after your initial treatment (like chemotherapy given before surgery), your doctors found that some cancer cells were still present in your breast or lymph nodes. This is sometimes called 'residual disease.' Also, you would need to have received PembroLizumab as part of your initial treatment regimen.

Both men and women can take part in this study, assuming they meet all the other specific medical criteria set by the research team. A healthcare professional would need to review your medical history in detail to confirm if this study is suitable 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 old or older?
Have you been diagnosed with early-stage triple-negative breast cancer?
Did you have some cancer remaining after your chemotherapy and initial treatment?
Did your initial treatment include PembroLizumab (KEYTRUDA)?
Are you happy to be randomly assigned to different treatments?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would be assigned to receive one of several different treatment plans. This assignment is done randomly, meaning it's like drawing names out of a hat, so neither you nor your doctor chooses which specific treatment you get. You would receive regular doses of the study medication, which might be given as an infusion (into a vein) or as tablets, depending on the treatment group you are in.

You would have regular visits to the hospital or clinic for check-ups, blood tests, scans, and to discuss any side effects you might be experiencing. These visits are important for monitoring your health and how well the treatment is working. The study will also ask you to complete questionnaires about your general health and how you're feeling to assess your quality of life.

After your active treatment phase ends, there will be a follow-up period where doctors will continue to monitor your health and check for any return of the cancer. The total duration of your involvement could be several years, including both the treatment and follow-up phases, to ensure a complete understanding of the long-term effects of the treatments.

Potential risks and benefits

Taking part in a clinical trial offers potential benefits, such as gaining access to new treatments that are not yet widely available and contributing to medical knowledge that could help future patients. However, there are also potential risks involved, as with any medical treatment. The study treatments may cause side effects, some of which might be serious, and the new treatments might not be more effective than standard care. All efforts are made to monitor your health closely and manage any side effects. It's important to remember that participating in a clinical trial is always voluntary, and you have the right to withdraw from the study at any time, for any reason, without affecting your usual medical 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
Netherlands

Common questions

What is triple-negative breast cancer?

It's a specific type of breast cancer that doesn't have certain features (receptors for oestrogen, progesterone, or HER2 protein) that other breast cancers might have, which means different treatments are needed.

What does 'residual disease' mean?

This means that after initial treatment (like chemotherapy before surgery), some cancer cells were still found in the breast or lymph nodes.

What is PembroLizumab (KEYTRUDA)?

It's a type of treatment called immunotherapy that helps your body's immune system fight cancer cells more effectively.

Will I know which treatment I'm getting?

In this study, treatments are assigned randomly, like a lottery. This helps researchers compare the treatments fairly, so you might not instantly know which specific drug you're receiving.

How long will I be involved in the study?

Your involvement could last for several years, covering both the period you receive treatment and a follow-up period to monitor your health over time.