Gene Therapy

Article excerpt

Balancing the Promise With the Reality

On September 17, 1999, four days after receiving a gene therapy infusion at the University of Pennsylvania, a young man from Arizona who had a genetic disease known as Ornithine Transcarbamylase Deficiency (OTC) died. His death--the first that could be directly linked to gene therapy--electrified the scientific community and triggered a national debate that will have a powerful impact on the future of gene therapy experiments and how they are approved and monitored. These are profound and important questions left unanswered, but for Jesse Gelsinger, the 18-year-old who died, and perhaps for others, it is a debate that came too late.

WHAT IS GENE THERAPY?

The concept of gene therapy was born when scientists theorized that if they could replace faulty genes with good ones, they would be able to cure hereditary disorders. The problem was how to get good genes into cells. Scientists knew that cells were masterful at protecting themselves, and that it would be important to insert new genes in a way that left them intact and able to function. They realized that one of the few entities that could enter a cell and reside inside for a long period of time was a virus. Thus, they launched a series of animal experiments using a genetically modified virus (called a "vector") that would carry a desirable gene, much like a passenger in a taxi, and drop it off in the targeted cell. To assure that the virus would not multiply and cause disease in the recipient, they modified it so it could not replicate after it delivered the gene.

During the 1980s, scientists working in this field realized that if gene transfer worked in humans, it would raise profound moral and ethical questions. Gene therapy, they theorized, could change the human race if there were no ethical parameters and no regulatory boundaries that scientists would have to obey. Moreover, designing new viruses would trigger environmental questions that could potentially pose new risks to humanity. In light of all this, they met together and proposed that the government should create an oversight structure called the Human Gene Therapy Subcommittee of the Recombinant DNA Advisory Committee (which is known as the "RAC"), to review pending gene therapy experiments and monitor the progress of the technology. These scientists felt that if gene therapy experiments were reviewed and discussed in open meetings by ethicists, scientists, and members of the public, it would build public trust and reduce fear of genetic engineering. The major threat to the future of gene therapy, they surmised, would be public suspicion that experiments conducted behind closed doors might lead to the creation of genetically engineered humans, potentially turning frightening science fiction into reality.

GOVERNMENT REGULATION

As a result of these recommendations, the National Institutes of Health (NIH) created the Human Gene Therapy Subcommittee, which developed a list of rules that scientists would have to abide by before, during, and after they transferred new genes into humans. These rules are parts of the "NIH Guidelines for Research Involving Recombinant DNA Molecules," and they are known as the "Points to Consider." The rules must be obeyed by all scientists who receive federal funds, as well as by private companies when treatment of patients is provided at a hospital that receives federal funds, such as Medicare or Medicaid. After the RAC would approve a protocol, scientists would have to obtain FDA approval before an experiment involving humans could begin.

EARLY TRIALS

Even though gene therapy was conceived as a technology that would treat or cure genetic diseases, within a short period of time, the great majority of experiments focused only on cancer. This was primarily because gene therapy experiments are very expensive, and the NIH was not generous in its funding to academic investigators who wanted to pursue gene therapy. …