Penn Researchers Create Cystic Fibrosis Gene Therapy Vector Using Pieces of HIV and Ebola
University of Pennsylvania researchers have developed a "promising" new cystic fibrosis gene therapy vector using pieces of genetic material from HIV and the Ebola virus, the Philadelphia Inquirer reports (Collins, Philadelphia Inquirer, 3/1). The vector's dual goal is to capitalize on HIV's "exceptional ability to persist in the body" and the Ebola virus' "unusual talent for attaching to lung cells" (Weiss, Washington Post, 3/1). Cystic fibrosis is an inherited disorder that attacks the lungs with a thick mucus, and patients usually die from lung damage or infection (AP/Richmond Times-Dispatch, 3/1). Researchers hope that the vector will someday be able to successfully insert into lung cells the gene that cystic fibrosis patients lack (Washington Post, 3/1). Scientists have thus far been able to design a vector that effectively accomplishes this goal in human and mouse lung cells in laboratory experiments (Philadelphia Inquirer, 3/1). The Washington Post calls the hybrid virus "the most extreme and controversial" strategy emerging in the field of gene therapy, although the vector does not contain parts of the two deadly viruses' genomes needed to cause disease. Penn researchers, led by James Wilson, the director of Penn's Institute for Human Gene Therapy, have shown that when the hybrid virus is "squirted into the windpipes" of laboratory mice, the virus infects the animals' lungs and successfully delivers "marker genes" contained in the vector. This research is published in today's issue of Nature Biotechnology.
Scientists disagree whether the HIV/Ebola vector is safe. W. French Anderson, a gene therapy "pioneer" at the University of Southern California, said of the hybrid virus, "It's not even HIV anymore; it's just pieces. And Ebola sounds horrible, but this has nothing to do with the Ebola virus that knocks out all your defense mechanisms and kills you. Those genes are gone." But Robert Gallo, director of the Institute of Human Virology and co-discoverer of HIV, disagreed, saying, "I wouldn't want this thing put into me." Gallo said that the new virus could potentially "combine with wild HIV to create an entirely new kind of contagious virus." These concerns were brought up at a 1998 FDA conference, during which FDA official Anne Pilaro warned that such viruses would present "unique issues regarding determination of safety" (Washington Post, 3/1). But human trials of the hybrid virus are a long way off, especially since the FDA has banned human gene therapy trials at the Penn institute following the death of teenager Jesse Gelsinger, a liver disorder patient who was undergoing gene therapy human trials at the institute. Furthermore, the FDA is still considering whether to deny Wilson the right to conduct human trials in the future, due to his participation in the Gelsinger trial. Nelson Wievel, the institute's deputy director said, "A clinical trial is way, way down the road" (Philadelphia Inquirer, 3/1).