If these studies are reliable, the drugs must exert some activity/mechanism that also fights this disease.
Yes, these uses are off-label, which is the med profession's way of distancing themselves from endorsing such empirical practices. It seems to be a legal position, protecting them from any consequence from undocumented side effects, that sort of thing. Of course, when death is the alternative the profession is not going to stand in the way.
They are correct that - in time - we need clinical studies involving use of these drugs in unstudied circumstances. I hope time will clarify these unprecedented practices.
A few weeks back I was posting about the dog de-worming medicine, Fenbendazole being used for cancer treatment; I urged Rush Limbaugh to consider the off-label alternative. If traditional treatment does not help him, I hope he will think about the alternative.
Ivermectin is also used as a de-worming med.