RecruitingPHASE3INTERVENTIONAL

A Study of Dato-DXd in Inoperable or Metastatic Hormone Receptor-positive, HER2 IHC 0 Breast Cancer

This research is testing a new medicine called Dato-DXd for women and men with advanced breast cancer. Specifically, it's for cancer that has spread or can't be removed by surgery, is sensitive to hormones (HR-positive), but doesn't show high levels of HER2 protein (HER2 IHC 0). Crucially, this study is for patients whose cancer has stopped responding to hormone treatments and who haven't yet started chemotherapy. The main goals are to understand how effective Dato-DXd is at treating this type of breast cancer and to check for any side effects. About 100 people will take part, receiving the treatment through a drip every three weeks until their cancer gets worse or side effects become too much.

At a glance

Status

Recruiting

Phase

PHASE3

Sponsor

AstraZeneca

Enrolment target

100

Start

30 Oct 2025

Estimated completion

02 Feb 2028

Breast Cancer

What is this study about?

This study is investigating a new treatment called Dato-DXd for a specific type of advanced breast cancer. This is for breast cancer that has spread to other parts of the body (metastatic) or can't be removed by surgery (inoperable). It’s also for breast cancer that is 'hormone receptor-positive' (meaning its growth is encouraged by hormones) and 'HER2 IHC 0', which means it tests negative for a protein called HER2. The research is focusing on patients whose cancer has stopped responding to standard hormone therapy, but who haven't yet started chemotherapy.

The main purpose of this study is to see if Dato-DXd can effectively shrink or stop the growth of this type of breast cancer, and to understand if it causes any unwanted side effects. Researchers hope that this new treatment might offer another option for patients before they need to consider chemotherapy.

About 100 people will be involved in this study. Everyone taking part will receive Dato-DXd. Researchers will regularly check how patients are doing to measure the treatment's success and to spot any side effects. This kind of research is really important for finding new ways to help people with advanced breast cancer.

Key takeaways

This study is testing a new drug, Dato-DXd, for advanced breast cancer.
It's for HR-positive, HER2 IHC 0 breast cancer that no longer responds to hormone therapy and before chemotherapy.
The treatment is given every three weeks through an intravenous drip.
Regular scans and blood tests are part of monitoring your health and the treatment's effect.
You can stop participating in the study at any time.

Who may be eligible?

To join this study, you would generally need to be 18 years or older with advanced breast cancer that either can't be removed by surgery or has spread. Your cancer must be HR-positive (meaning it’s affected by hormones) but low in a protein called HER2 (HER2 IHC 0). A key requirement is that your cancer has previously been treated with hormone therapy and is no longer responding, but you haven't yet started chemotherapy.

You also need to be fit enough for the study, meaning you are generally active and able to look after yourself, with a life expectancy of at least 12 weeks. You would need to provide a recent sample of your tumour or allow one to be taken. Your blood tests, especially those checking your bone marrow and organ function, would need to be within a healthy range.

There are also some things that would mean you couldn't join. For example, if your general health isn't considered stable enough, or if you have certain other serious medical conditions. The study team would carefully go through all these details with you to see if it's the right fit.

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 advanced breast cancer (inoperable or metastatic)?
Is your breast cancer HR-positive and HER2 IHC 0?
Has your cancer stopped responding to hormone therapy?
Have you NOT yet started chemotherapy for your advanced breast cancer?
Are you generally well and active for your age?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would receive the study drug, Dato-DXd, through a drip into your arm every three weeks. Each cycle of treatment lasts 21 days. You would continue to receive this treatment as long as your cancer isn't getting worse according to imaging scans, and as long as you're not experiencing difficult side effects. You can also decide to stop at any time.

Throughout the study, you'll have regular hospital visits. This will involve physical exams, blood tests, and scans (like CT or MRI) to check how the treatment is working and to monitor your health. Scans will be done every 8 weeks for the first 48 weeks, then every 12 weeks after that until your cancer progresses. You will also be asked to provide tumour samples (biopsies) at the start and, if possible, if your cancer progresses. Blood samples will also be collected regularly to look for certain markers related to the treatment.

The study team will explain exactly what's involved in terms of visits, tests, and medication schedule before you make any decisions. You'll have plenty of opportunities to ask questions.

Potential risks and benefits

Taking part in a clinical trial can have potential benefits, like gaining access to a new treatment before it's widely available, which might help control your cancer. However, there are also potential risks related to the treatment itself, which might cause side effects. It's important to remember that this new drug might not work for everyone, and it could have side effects that are not yet fully known. The study team will explain all known side effects. You are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (40)

Research Site
Verified postcode
Largo, United States· Withdrawn
Research Site
Verified postcode
Fort Wayne, United States· Recruiting
Research Site
Verified postcode
Omaha, United States· Recruiting
Research Site
Verified postcode
New York, United States· Not yet recruiting
Research Site
Verified postcode
Houston, United States· Recruiting
Research Site
Verified postcode
Puyallup, United States· Recruiting
Research Site
Verified postcode
Beijing, China· Recruiting
Research Site
Verified postcode
Changsha, China· Not yet recruiting
Research Site
Verified postcode
Guangzhou, China· Recruiting
Research Site
Verified postcode
Linyi, China· Recruiting
Research Site
Verified postcode
Shandong, China· Not yet recruiting
Research Site
Verified postcode
Wuhan, China· Not yet recruiting

Common questions

What kind of cancer is this study for?

This study is for advanced breast cancer that is hormone-sensitive (HR-positive) but doesn't have high levels of HER2 protein (HER2 IHC 0), and has stopped responding to hormone therapy.

What is Dato-DXd?

Dato-DXd is a new drug being tested in this study. It's given through a drip.

How often would I get the treatment?

You would receive the Dato-DXd treatment through a drip once every three weeks.

What happens if the treatment stops working or I have bad side effects?

If your cancer gets worse or side effects become too difficult to manage, you would stop receiving the study treatment.

Will I have to have biopsies?

Yes, you would need to provide a tumour sample at the start, and possibly another if your cancer progresses, to help researchers understand the treatment better.

How to find out more

AstraZeneca Clinical Study Information Center

information.center@astrazeneca.com 1-877-240-9479 Official trial record

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