"In our minds, you really need [growth hormone] to be small and unmodified," Jonathan Leff, chief medical officer (CMO) for Ascendis Pharma A/S, told BioWorld, since such therapy must "get out of the bloodstream, penetrate into small nooks and crannies such as bone growth plates, and adipose tissue that's poorly vascularized. You don't mess with Mother Nature. It sounds simple and trite, but it's absolutely true in this case."