&gt; regulatory bodies do not tend to support rapid iteration of products<p>I disagree.  21 CFR 820 is deliberately written such that it does not prescribe any one specific development process; AAMI TIR-45 for example aligns agile methodologies with medical device software development and is an FDA recognized consensus standard.<p>What regulatory bodies do demand is that one document what one will do, and then, actually do what one has documented.  Sounds like Theranos had trouble with that.