A study looking at ribociclib and letrozole for people with advanced breast cancer (COMPLEEMENT-1)

This study is for people with breast cancer that has come back in the area where it was first found, or that has spread elsewhere in the body.

It is open to men and women whose breast cancer cells have:

• receptors for oestrogen or progesterone (hormone receptor positive)

• low or no amounts of HER2 (HER2 negative breast cancer)

Also, they have not had any hormone therapy for their advanced breast cancer.