I think its quite interesting that Lilly is testing baricitinib for diabetic nephropathy.. If this indication pans out, it would underscore how versatile JAK inhibitors are. It seems to be a pretty large unmet need.
This is one of many instances where several cytokine pathways are involved in causing harm. A single inhibitor may or may not do much good (best f'rinstance is aspirin, which turns the double-edged eicosanoid family mostly anti-inflamatory). Another interesting possibility is "classic" interferon inhibition, which is of unknown safety, but pretty much cures the common cold. ANYway, if you have a bunch of money and time, and have a well-tolerated inhibitor of a relatively-little-investigated cytokine pathway, it makes sense to do some testing in conditions where that kind of mechanism is active (and really, that's the situation in RA, too: COX-2 inhibition helps, TNF inhibition helps, inhibition of cellular attack helps and now JAK inhibition helps. So far, combinations have given modest therapeutic benefit with much worse side effects, but that may not always happen)