I don't have any experience with Sirolimus, but just from what I could pick up from a quick search I didn't see anything about it that was any scarier than for other immunosuppressants, including cyclosporine. Did I miss something? In fact the advantage seems to be that it would be much easier on your kidneys, which is something my husband has to constantly battle with the cyclo.
On the other hand, ATG/cyclo has a proven track record that is better than any other IST protocol for AA, at least so far. The fact that you responded the first time would tend to lean me in that direction, that and the 10 trips to LA! Who pays for that, does the trial cover all travel and lodging costs? Still humbug!
How quickly did you do the taper? Ken also relapsed from a too-quick taper, but a second ATG turned it around for him. That was in Feb. '06. He's still taking cyclo and it's possible now he'll have to remain on it indefinitely, but he's transfusion-free, stable, feels fine, and his counts continue to improve gradually. Much as I would like to see clinical trials done on anything that might help give his kidneys a break, I'm not sure this trial is the best thing for you at this point.
-Lisa, husband Ken age 60 dx SAA 7/04, dx hypo MDS 1/06 w/finding of trisomy 8; 2 ATGs, partial remission, still using cyclosporine