AuthorisedPhase II and Phase III (Integrated)Interventional

A randomized, double-blinded, placebo-controlled, multicenter, phase II/III efficacy and safety study of oral TherO2-01S22 as add-on therapy on top of first line anti-HER2 targeted treatment of patients with Metastatic Breast Cancer TherO2-01S22 in HER2-positive breast cancer: TherO2-MBC Study

This clinical trial is looking at a new oral medicine called TherO2-01S22. It's for people who have advanced breast cancer, specifically a type known as HER2-positive, which has spread to other parts of the body (metastatic). The main goal is to see if adding TherO2-01S22 to existing first-line HER2 treatments helps to shrink or get rid of tumours. Researchers will also check if the medicine is safe and look at how long people live without their cancer getting worse, and their overall quality of life. Participants will receive either the new drug or a placebo (a dummy drug) along with their standard treatment, and doctors will carefully monitor their health. This is a vital step in finding new ways to treat breast cancer.

At a glance

Status

Authorised

Phase

Phase II and Phase III (Integrated)

Sponsor

Centre Regional Lutte Contre Le Cancer

Enrolment target

224

Start

03 Oct 2025

metastatic breast cancer

What is this study about?

This study is a clinical trial, which means it's a research study exploring new ways to treat a disease. The disease in this case is metastatic breast cancer that is HER2-positive. 'Metastatic' means the cancer has spread from where it started to other parts of the body. 'HER2-positive' is a specific type of breast cancer that has a lot of a protein called HER2, which helps cancer cells grow.

The main goal of this study is to test a new oral medication called TherO2-01S22. Researchers want to see if adding this new drug to the standard treatments that already target HER2 can help control the cancer more effectively. They will be looking to see if tumours shrink or disappear after treatment. This is a combined Phase II and Phase III study. Phase II studies look at how well a new treatment works and if it's safe, while Phase III studies compare the new treatment to existing ones to confirm its benefits and safety in a larger group of people.

Throughout the study, doctors will be closely monitoring how participants respond to the treatment. They will check how long people's cancer stays stable and how long they live. They will also pay very close attention to any side effects to make sure the treatment is safe. Patients' quality of life will also be an important measure. This research is crucial because it helps scientists understand if new drugs like TherO2-01S22 can offer a better future for people living with this type of breast cancer.

Key takeaways

This study tests a new oral drug, TherO2-01S22, for HER2-positive metastatic breast cancer.
It aims to see if adding it to standard treatments can shrink tumours and improve outcomes.
Participation involves receiving the study drug or placebo, alongside standard chemo, and regular monitoring.
It is a 'double-blinded' study, meaning you won't know if you're getting the active drug.
Researchers will closely monitor safety, response to treatment, and quality of life for up to two years.

Who may be eligible?

To be part of this study, you would need to be at least 18 years old. Both men and women are welcome to participate.

The study is specifically for people who have been diagnosed with metastatic breast cancer that is HER2-positive. This means your breast cancer has spread to other parts of your body, and tests have shown it has high levels of the HER2 protein.

More detailed criteria will be discussed by the study team, but generally, participants will be starting their very first treatment for their metastatic HER2-positive breast cancer.

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?
Do you have breast cancer?
Has your breast cancer spread to other parts of your body (metastatic)?
Is your breast cancer HER2-positive?
Are you about to start your first treatment for this metastatic HER2-positive breast cancer?

Answer every question to see your result.

What does participation involve?

If you join this study, it's a long-term commitment. You will receive either the new study drug, TherO2-01S22, or a placebo (a dummy syrup that looks and tastes the same) by mouth, alongside your standard anti-HER2 treatments like Trazimera, Perjeta, Paclitaxel, Docetaxel, or Vinorelbine, which are given by infusion. The study is 'double-blinded,' meaning neither you nor your doctor will know if you're getting the active drug or the placebo.

You'll have regular hospital visits for treatments, blood tests, and scans to check your cancer. At day 43, doctors will specifically check to see if your tumours have shrunk. They will monitor your progress every three months for up to two years, looking at how long your cancer is controlled and your overall health. You'll also complete questionnaires about your quality of life. Blood samples will be taken at specific times (before and after taking the oral drug on certain days) to understand how the body processes the medications. The detailed safety checks will continue until day 64 after your last dose of the study drug.

Potential risks and benefits

Participating in a clinical trial offers potential benefits, such as access to a new treatment before it's widely available, and helping others by contributing to medical knowledge. However, there are also potential risks, as the new drug might have side effects that aren't fully known, and it might not work for everyone. You could also receive a placebo instead of the active drug. Throughout the study, your health will be closely monitored by medical professionals, 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
France

Common questions

What does 'HER2-positive' mean?

It means your breast cancer cells have too much of a protein called HER2, which helps them grow. Specific treatments target this protein.

What is a placebo?

A placebo is a 'dummy' treatment that looks just like the real medicine but contains no active drug. It helps researchers compare the new drug's effects.

What does 'double-blinded' mean?

It means neither you nor your study doctor will know if you are receiving the new drug or the placebo during the trial.

What is an 'objective response rate'?

This is a way doctors measure how well the treatment is working by seeing the percentage of patients whose tumours shrink or disappear after receiving the study treatment.

What is 'quality of life' in this study?

It refers to how you feel physically and emotionally, and how well you can go about your daily life. You'll answer questionnaires about this.