Diabetic nephropathy is a growing market with 7% growth since 2005 and it is expected to be a 2.37 B market by 2017. ACE and ARB inhibitors are used but fact is that these drugs can hurt the kidneys especially in a dehydrated patinet and there is a room for better therapies. LLY and INCY are conducting a Phase II B trial of their JAK2 compound " Baricitinib" for this indication, in addition for a Phase III trial in Rheumatoid arthritis started last month. PFE earlier has done some phase II studies of their drug Xeljanz in kidney transplant patients and results were good against Cyclosporins.
I see VX 509 doing a roburst business in future once approved. Better side effect profile will be the key determinent of a JAK compound leader. PFE didn't pursue kidney transplant because of poor side effect profile as I understand.