A clinical trial to look at how safe new treatment combinations are and how well they work for people with breast cancer that has grown and cannot be removed with surgery, or has spread in the body

1. Why is the MORPHEUS-panBC clinical trial needed?

Breast cancer can be challenging to treat if it has spread to nearby tissues and cannot be removed with surgery (known as ‘locally advanced unresectable breast cancer’) or if it has spread to other parts of the body (known as ‘metastatic breast cancer’). Standard treatment includes chemotherapy (such as capecitabine, nab-paclitaxel and carboplatin) and/or hormone or targeted treatments (such as atezolizumab) depending on the type of breast cancer a person has.

New treatment combinations are needed to improve health outcomes for people with locally advanced unresectable or metastatic breast cancer. New treatment combinations are not currently approved as standard for treating breast cancer.

This clinical trial aims to compare the effects, good or bad, of new treatment combinations in people with locally advanced unresectable or metastatic breast cancer.

2. How does the MORPHEUS-panBC clinical trial work?

This clinical trial is recruiting people with certain types of locally advanced unresectable or metastatic breast cancer. People can take part if they also fit other criteria to join a treatment group.

People who take part in this clinical trial (participants) will be given the clinical trial treatment for as long as it can help them unless they have unacceptable side effects. The clinical trial doctor will see them regularly. These hospital visits will include checks to see how the participant responds to the treatment, and any side effects they may have. The total time of participation in the clinical trial may be 1–2 years for treatment, plus follow-up time after the last dose of treatment to check for any side effects. Participants who have cancer that gets worse while they are being given a particular clinical trial treatment, or who have unacceptable side effects, may be able to be given a different treatment in this clinical trial if they meet the criteria. Participants can stop trial treatment and leave the clinical trial at any time.

3. What are the main endpoints of the MORPHEUS-panBC clinical trial?

The main clinical trial endpoint (the main result measured in the trial to see if the drug has worked) is the number of participants whose cancer shrinks or disappears during treatment (objective response rate).

The other clinical trial endpoints include:

• The length of time between the start of the trial and participants’ cancer progressing (progression-free survival)
• The number of participants whose cancer stays the same, shrinks or disappears for at least 3 months during treatment, (disease control rate)
• How long participants live (overall survival)
• The length of time between participants’ cancer starting to shrink to cancer progressing (duration of response)
• The number and seriousness of any side effects

4. Who can take part in this clinical trial?

People can take part in this trial if they are at least 18 years old, have locally advanced unresectable or metastatic breast cancer, and can have a sample of breast cancer taken (known as a ‘biopsy’). They must also meet certain criteria to join a particular treatment group, including the type of breast cancer they have – such as triple-negative breast cancer (TNBC), ER-positive or HER2-positive breast cancer – and which treatments they have been given before, if any.

People may not be able to take part in this trial if they have cancer that has spread to the brain or spinal cord and causes symptoms, certain medical conditions such as heart or lung diseases or certain infections, have had severe reactions to previous cancer treatment, or are pregnant or breastfeeding.

5. What treatment will participants be given in this clinical trial?

Everyone who joins this clinical trial will be placed into a treatment group that they fit the criteria for. The treatment group will depend on the participant’s breast cancer type and any treatments they have received before.

Treatments will be given as combinations of pills (to be swallowed), injections under the skin, or infusions (into the vein) in treatment cycles – a treatment cycle is the period of treatment and recovery time before the next dose of treatment is given – a cycle is usually 3 or 4 weeks.

This is an open-label trial, which means everyone involved, including the participant and the clinical trial doctor, will know the clinical trial treatment the participant has been given.

6. Are there any risks or benefits in taking part in this clinical trial?

The safety or effectiveness of the experimental treatment or use may not be fully known at the time of the trial. Most trials involve some risks to the participant. However, it may not be greater than the risks related to routine medical care or the natural progression of the health condition. People who would like to participate will be told about any risks and benefits of taking part in the clinical trial, as well as any additional procedures, tests, or assessments they will be asked to undergo. All of these will be described in an informed consent document (a document that provides people with the information they need to decide to volunteer for the clinical trial).

Risks associated with the clinical trial drugs
Participants may have side effects (an unwanted effect of a drug or medical treatment) from the drugs used in this clinical trial. Side effects can be mild to severe, even life-threatening, and vary from person to person. Participants will be closely monitored during the clinical trial; safety assessments will be performed regularly.

Participants will be told about the known side effects of clinical trial drugs and possible side effects based on human and laboratory studies or knowledge of similar drugs. Participants will also be told about any known side effects of swallowing pills, being given injections under the skin (subcutaneous injections), or infusion into the vein (intravenous infusions).

Potential benefits associated with the clinical trial
Participants' health may or may not improve from participation in the clinical trial. Still, the information collected may help other people with similar medical conditions in the future.