>> It could be that Levitt doesn't want investors badgering the clinicians and patients involved in the trials. <<
That’s a red herring, IMO. Most trial sites have a public liaison whose job is to field questions. For instance, I spoke with the liaison at University of Chicago about GENR’s trial in prostate cancer (#msg-3226907).
Many biotech companies do disclose their trial sites and are proud to have the implicit endorsement of top-flight institutions.