Hi! Welcome to our board. Your sister is lucky to have your support! There are many drugs that are used to fight metastatic BC (mets). Many oncologists think of mets as a chronic disease that can be controlled, if it responds to therapy. There seems to be a "laundry list" of drugs that they refer to, and if the first drug doesn't work, they try the next one on the list. www.breastcancer.org
is the most comprehensive site with breast cancer info. That's a good place to start. There are many women here who are going through similar situations and will chime in with more specific info. The board seems to be a bit "sleepy" as of late, so don't be afraid to come back with more questions and more people may respond and help you! Good luck to both of you!