BETA - What is the difference between relapsed and refractory AML?

What's the difference between relapsed and refractory AML? Relapsed AML is when the AML responds to the first treatment and at some point the AML comes back. On the other hand, the refractory AML is the AML that's resistant to initial treatment. By definition, it requires about two rounds of reasonably intensive chemotherapy before we call a disease resistant. In one case, for relapsed AML, the disease is possibly sensitive to initial chemotherapy, whereas for refractory AML, the disease is essentially insensitive to the initial chemotherapy.