The losartan possibility
Date: March 1, 2012
Even as the drug losartan is well into multicenter phase III clinical trials for Marfan syndrome, it’s being eyed for Loeys-Dietz syndrome. That’s in large part because of animal models that pediatric cardiologist Hal Dietz has developed for both disorders. Marfan mouse models given losartan—a well-known angiotensin receptor blocker—show aortic growth that is indistinguishable from normal mice. Losartan appears to keep their aortas from enlarging, says Dietz, as well as prevent aortic dissection and death. It may do the same for the new Loeys-Dietz models, which, like Marfan mice, share excessive activity of a specific growth factor, TGF-ß.
“What’s more,” says Dietz, “we’ve found a window of opportunity that remains open after birth, when you can still use losartan to turn things around in the Loeys-Dietz mice and slow the aorta’s growth rate.”
Yet clinical trials for the more aggressive Loeys-Dietz are harder to plan, Dietz adds, “because we are uncomfortable watching even mildly dilated aortas in this condition, and normally move quickly to surgery. We’re waiting for definitive results in the mice before considering a trial, but so far, we’re optimistic.”