A trial of buparlisib for advanced breast cancer that is hormone receptor positive and HER2 negative (BELLE 2)

This trial looked at a drug called buparlisib for breast cancer that had spread into tissue surrounding the breast or elsewhere in the body.

It was for women whose breast cancer:

• had got worse despite having a hormone therapy drug called an aromatase inhibitor

• was hormone receptor positive

• was HER2 negative

We call breast cancer that has receptors for the hormones oestrogen and progesterone, hormone receptor positive breast cancer. Breast cancer cells often have receptors for a protein called HER2. If there are only small numbers of these receptors, the cancer is called HER2 negative.