A trial of TDM1 and pertuzumab for breast cancer that has spread - MARIANNE

This trial is looking at 2 new drugs called trastuzumab emtansine (TDM1) and pertuzumab for breast cancer that has spread to another part of the body (secondary breast cancer) or has come back in the same area (local recurrence). It is for people who have breast cancer that is HER2 positive.

Some breast cancers have large amounts of a protein called HER2 on the surface of the cells. These cancers are ‘HER2 positive’ and can be treated with a drug called trastuzumab which targets the HER2 protein.

You may have trastuzumab with chemotherapy. Paclitaxel and docetaxel are drugs that doctors often use.

Pertuzumab is a type of biological therapy called a monoclonal antibody. It works by targeting the HER2 protein but in a different way to trastuzumab. We know from research that having both pertuzumab and trastuzumab together may be better than having just one of them alone.

Trastuzumab emtansine (TDM1) is a combination of trastuzumab and a chemotherapy drug called DM1. Trastuzumab finds the cancer cells and delivers the DM1 to them. This type of drug is called a conjugated monoclonal antibody.

The researchers think that TDM1 alone, or in combination with pertuzumab may work well for people with HER2 positive breast cancer that has spread or come back in the same area. But they are not sure. In this trial, they will also compare it with a standard combination of trastuzumab and paclitaxel or docetaxel.

The aims of the trial are to find out which combination of drugs

• Works best for breast cancer that has spread or come back in the same area

• Is the safest