What are my odds?
Technicalities aside, the most important question that has been hovering in your mind is how bad the condition is, or what is the risk of death in such cases. To put it simply, it varies widely according to the severity of the condition and the response to initial therapy. If secondary therapy were as effective as the initial, there would be no additional therapy, but they have some severe side effects and tend to not increase survival. The more severe the condition is, and the more organ systems involved, the less likely for the disease to be manageable.
Causes of death are diverse according to the organ most affected. The disease itself can cause death by depleting your blood of platelets and causing severe hemorrhage, weak immunity -despite the vigorous autoimmune reaction- leading to increased susceptibility to infections or liver affection in acute cases and liver failure. The medications used also have strong immunosuppressive effects, predisposing to infections.
Preventing GVHD remains the main goal in management and the greater contributor to overall survival.