I'm happy to hear her scan had a positive note, my thoughts and prayers are with you and your whole family.
Just to reply to your (justly) frustrated question about children's cancer drugs: I study Medical Ethics, and one of the paradoxes in research with children is that researchers and governmental agencies are so concerned about not harming children and about not exploiting their participation, that consequently it is very difficult to do research on children as there are so many regulations for it. The ironic result is that there has been comparatively little progress made in children's medicine. You are right - it is totally ridiculous, and needs to change - our children need progress! I am so happy to hear that the "off-label" use of the adult drug appears to be working for your daughter and I hope that research will progress such that any future medical needs will be taken care of with drugs made especially for tots.