Clinical Use of Non-Viral Vectors
Three-fourths of the currently active clinical protocols employing non-viral vectors involve intramuscular injection of plasmids expressing antigenic epitopes of a number of pathogens. Many of these trials involve vaccination against HIV-1 and are in phase I testing (Girard, 2006). One trial employing a three plasmid DNA vaccine for Ebola infection has completed phase I testing and will enter phase II alone and in combination with a recombinant adenovirus vector in a prime-boost dosing regimen (Martin, 2006). Severalhuman trials using non-viral vectors to treat genetic diseases such as hemophilia A, CF, alpha-1-antitryp-sin deficiency and Canavan disease illustrate the challenges of permanent correction of a hereditary disorder with a plasmid-based system (O’Connor, 2006). Despite this, some investigators continue to refine and develop additional non-viral systems for treating CF (Lee, 2005).