It's in vitro because they're using blood samples from their repositories. It's a typical request from large institutions to ask patients in studies to donate blood samples at baseline and possibly completion so that investigators can use them for basic research to answer questions and to publish. In vitro just means in a tube. Any blood test is in vitro.
Cheaper, quicker, no enrollment process for The Cydy LL paper. Obviously the results did not impress the market as much as Naders continued foot in mouth program with failed tout PR videos and empty press releases.