It sounds like your mom may be ER+ and Her2+. You should definitely confirm this with her doctor, as this does obviously impact treatment options.
Your mom was previously on Femara, which is an anti hormonal but it works differently than tamoxifen. So having one hormonal fail does not mean that NONE will work. There is also research on identifying the causes, and someday how to reverse resistance.
Since your mom had such a great response to the chemo combo, the thinking may be to back off a bit to something less taxing and see if the combination of blocking Her2 and ER will keep things stable.
If your mom is Her2+, there should ALWAYS be a Her2 targeted agent in the mix, if she is also ER+ it makes sense to block both.
The research on blocking these growth mechanisms (i.e. Estrogen or Her2 is fueling the growth) largely points to the benefits of blocking multiple pathways at the same time, that way it's harder for the cancer to find another way to grow.
Chris in Scotts Valley
June 2002 extensive hi grade DCIS (pre-cancer-stage 0, clean sentinal node) Mastectomy/implant - no chemo, rads. "cured?"
9/2004 Diag: Stage IV extensive liver mets (!) ER/PR- Her2+++
10/04-3/05 Weekly Taxol/Carboplatin/Herceptin , complete response!
04/05 - 4/07 Herception every 3 wks, Continue NED
04/07 - recurrence to liver - 2 spots, starting tykerb/avastin trial
06/07 8/07 10/07 Scans show stable, continue on Tykerb/Avastin
01/08 Progression in liver
02/08 Begin (TDM1) trial
08/08 NED! It's Working! Continue on TDM1
02/09 Continue NED
02/10 Continue NED. 5/10 9/10 Scans NED 10/10 Scans NED
12/10 Scans not clear....4/11 Scans suggest progression 6/11 progression confirmed in liver
07/11 - 11/11 Herceptin/Xeloda -not working:(
12/11 Begin MM302 Phase I trial - bust:(
03/12 3rd times the charm? AKT trial
5/12 Scan shows reduction! 7/12 More reduction!!!!
8/12 Whoops...progression...trying for Perjeta/Herceptin (plus some more nasty chemo!)
9/12 Start Perjeta/Herceptin, chemo on hold due to infection/wound in leg, added on cycle 2 &3
11/12 Poops! progression in liver, Stop Perjeta/Taxo/Herc
11/12 Navelbine/Herce[ptin - try for a 3 cycles, no go.
2/13 Gemzar/Carbo/Herceptin - no go.
3/13 TACE procedure