[Becky]

Dear Andi


Currently there is a major, large study going on that is comparing the three aromatase inhibitors (AIs - Arimidex. Femara and Aromosin). As with studies of this nature, it will take years and years to see if there is a long term difference in disease free survival and overall survival. I believe there won't be a difference in short term results (and probably not long term results either but we do have to wait). That said, Arimidex and Femara work by inhibiting aromatase (an enzyme that helps convert androgens to estrogen) in the same biochemical reaction. Aromosin works in a different way. This is why I have advised women on this board who want to switch from Arimidex to another AI (because of side effects) to switch to Aromosin as Femara works the same way and if they have a bad side effect with Arimidex, they will most likely have the same side effect with Femara (although they may have the same results with Aromosin but it is a better shot that they may not).

There is a study on hormone positive women with bone mets (and only bone mets) where the AIs (all 3) are tested alone. In this test (of only about 20 women) it seemed that Femara worked better but it was a very small study and the result was not statistically significant. See next message as this was deemed too long.