anyone heard of femara for homone negative?

I saw the doctor last Friday and then Tuesday , the nurse called and said, the doc wanted me to go on femara. I'm Her2/nue+++ but ER-, PR-. I've never heard of this and can't discuss it with the doc right now because my onc is out of the country and I've had "fill in" onc since June. Has anyone heard of this? I'd appreciate any info on this, one way or the other. BERTA