I know this is a really old post, but is there any update on this? I can't find anything newer than 2009 via google.
I read an interview with one of the head developers of this. He said the main reason it fell through was due to technological shortcomings. Namely, they couldn't get the siRNA to penetrate into the skin.
However, researchers from Northwestern have just developed a topical delivery method to do just that!...http://www.northwestern.edu/newscenter/stories/2012/07/skin-disease-treatment.html
I wonder if the people from Sirna will pick up on this new technology and continue with their project!!