Hi Dhruba,
Cyclosporine alone has been used successfully to treat SAA. The response rate is lower than if used in combination with ATG.
http://www.ncbi.nlm.nih.gov/pubmed/16270758
As Lisa pointed out ATG or BMT are typically the first line of defense for SAA. However, if ATG is not available, cyclosporine is an alternative.
While waiting for the response, can you start the HLA testing on her sibling? This process takes time so it would be beneficial to start it now.
Also, you may want to have her EPO levels measured to see if she is a candidate for EPO shots as an alternative to RBC transfusions.
Also, do you know her absolute reticulocyte count? A high reticulocyte count at diagnosis is a good predictor of response to IST.