Hi kjraimondi. I'm glad that your ATG treatment seems to be working, even if it's working slowly.
It's good news that you have matched unrelated donors, so you have that as a backup choice. Being healthy, other than having SAA, makes you a much better candidate for a successful transplant than someone with other health problems, but ATG is the first choice for adults because it has a good success rate, can be repeated, and is less risky than a transplant.
In general, the younger you are, the better the rate of success for transplants. Transplants may even be preferred for the youngest patients and they tend to go well for teens too. Transplants for people age 50, 60, 70 are riskier. Age 30 is in the middle.
If by "data" you mean survival statistics, the National Marrow Donor Program keeps statistics on SAA transplant survival rates, but you have to use their stats with a large grain of salt, both because it covers patients who may have other health conditions, patients who are younger or older, and because it covers older data. Improvements in pre-transplant care, the transplant process, and post-transplant care continue to increase the odds of success each year, so older data always paints a less optimistic picture than if we had the latest statistics. With that caveat,
here is a chart (from
this page) showing 70% one-year survival and 60% 5-year survival over all unrelated-donor transplants for SAA in the range from 12 years ago to 3 years ago.
Being otherwise healthy puts you in a better-than-average category but I haven't seen any statistics on how that affects SAA transplant outcomes.
The NMDP also has transplant statistics by transplant center. For example, you can look up the fact that the M.D. Anderson Cancer Center at the University of Texas did 4 unrelated donor transplants for SAA from 2004 to 2008 and all 4 had survived at 1 year (the only interval they reported).
Even if it's too soon to think that you need a transplant, I think it's a smart move that you are asking questions and learning about it, so you'll be well-informed and have the most realistic idea about what your choices are.