Dave,
I am so sorry, I did not know you had LGL - you have my prayers and support always. So many drugs are used off label that I thought that was your question.
Looking at your question from the view point of treating LGL and knowing you from your very wise posts I would believe you have investigated this drug well.
Would I use this drug - if there were no other choices left to me or my hubby and children, yes I would go for it.
Loss my sister to ovarian cancer little over a year ago and she chose to go for anything that may help her. She was a very brave woman and I loved her dearly - so much grit -
I have your back, Dave,
Kindly,
Kitt