Possibly losartan, according to Shoemaker.
This is really interesting. Losartan is currently being studied in patients with the most severe form (Type IV Vascular) Ehlers-Danlos syndrome, which is genetic in origin. It is also seeing use in other forms of EDS and Marfan's. It also seems to be unique to losartan among all the other drugs in its class (angiotensin receptor blockers).
I suspect losartan does something with collagen, although I'm not certain what - but it could be very useful. Understanding the mechanism could be even more interesting in that it might possibly help explain connections between ME and Ehlers-Danlos / hypermobility.
The study I'd love to see is whether ME patients with hypermobility have higher levels of TGF-Beta than ME patients without it, and whether it correlates with Beighton score. Also interesting would be whether there is a difference between men and women, since ME affects women far more than men, and EDS does as well.
Is EDS entirely genetic, or is there an environmental, and modifiable (!) component to it? Would the same treatment help ME patients?