Between my online research and discussions with Ryan’s doctor, here is what I have learned so far:
The only cure is a fully matched bone marrow transplant from a sibling. Ryan does not have a fully matched sibling. His sister is a half sister, so it is highly unlikely she would be a match.
A non-fully matched bone marrow transplant (most likely from an unrelated donor) is not recommended unless immunosuppressive therapy does not work. This is because the success rate for this type of transplant is only around 50% and there is a 60-80% chance of Graft-Versus-Host Disease (GVHD). GVHD is condition where the new transplanted cells regard the recipient's body as a foreign. When this happens, the newly transplanted cells attack the recipient's body.
The ATG treatment Ryan is receiving is not a cure, but it has the potential to put him into a partial or full remission. The doctor feels there is about a 75% chance it will put Ryan into remission. However, from what I have read online, there is about a 69% chance of remission and the vast majority of patients only seem to be able to achieve a partial remission. I found one study that indicated that only about 20% achieve a full remission.
The ATG treatment has a 15% chance of giving Ryan leukemia or myelodysplastic syndrome (MDS), a blood disorder that can turn into Leukemia. MDS is what Robin Roberts of Good Morning America was diagnosed with and received a bone marrow transplant to treat.
The combination of medications Ryan will be taking once he gets out of the hospital (Cyclosporine and Prednisone) also have nasty side effects, including a warning on the Cyclosporine that a “common” side effect is kidney damage. There are also some rare side effects that include scary things like “Any disorder of the brain”, "Progressive Disease in the White Matter of the Brain", "Brain-capillary Leak Syndrome", and if the 15% chance of leukemia from the ATG treatment isn't enough, a rare side effect of Cyclosprorine is "Malignant Lymphoma"
I feel like I am voluntarily poisoning my sweet 4-year old boy. However, I know that if he isn't given these treatments, he will likely die. There are no good options. We just have to try to make the best choices we can.