April 27, 2000 -- For the longest time, there has been talk about how gene therapy holds great promise for the future of medicine. Well, it looks like the future is now. Gene therapy is finally showing signs of being a promise kept, thanks to some French researchers.
In the April 28 issue of Science, the researchers detail their success in using gene therapy to treat children whose faulty immune systems otherwise would have forced them to spend their lives in a sterile "bubble." In the wake of the death last fall of an Arizona teen-ager during a University of Pennsylvania gene-therapy experiment, the latest advance is leading to renewed hope for the technique.
But what exactly is that hope? A drug-free, permanent solution for many types of disease, it would seem.
Drugs work from the outside in, and must be continuously re-administered if the disease is chronic. Gene therapy works from the inside, and should keep working indefinitely. A key struggle for researchers is finding the right gene to address the disease in question, and making sure that gene is delivered to the right place in the body.
Which brings us to the recent success. The disease the French researchers may have cured is well known, but rare. Does gene therapy hold promise for the big daddies of disease: cancer, diabetes, heart disease? You bet, and then some.
W. French Anderson, MD, is credited with performing the first gene treatment in 1990 (for the same type of disease treated by the French researchers). He tells WebMD that the recent gene therapy successes are analogous to man's first landing on the moon.
"We started off with a big burst of enthusiasm, just like [what] happened when [President] Kennedy made the announcement we're going to beat the Russians to the moon. And then there's all this high hope, and everybody rushes out to watch the rockets go up, and they blow up," Anderson says, making the comparison to the death in the Pennsylvania trial. "Things got really bad for a while, then all the little parts started working. ... We made it." Anderson, who wrote a commentary about the French research in Science, is director of the gene therapy laboratories at the University of Southern California in Los Angeles.
The disease involved in the French research, and in Anderson's early work, is called severe combined immunodeficiency disease (SCID), and is very rare. Genetically speaking, it affects a single gene, so it is more basic than many other diseases.
The new research "establishes as a fact that if you can get enough gene-corrected cells into the body, you can correct the disease," Anderson tells WebMD. "So it's been done first with SCID; now it's a matter of working out the conditions for other diseases. In fact, hemophilia [treatment], looks like that's going to be successful; growing new blood vessels for cardiovascular disease looks successful; some of these gene-based vaccines for cancer ... those look very promising." Using gene therapy to treat the AIDS virus also shows huge potential, he says.
It will take longer to find solutions to certain diseases like diabetes and sickle cell anemia, Anderson says, because they involve multiple genes. "We're just getting over the cusp of being able to get a single gene in, much less being able to get two genes in or three genes, and have them [work] properly, and so on," he tells WebMD.
Some researchers are also having success with gene therapy in mice. "There are a number of indications now that finally we've learned enough; we've made the system efficient enough that gene therapy is now turning the corner and is starting to see some success clinically," Anderson says.
Fears about safety have also calmed down, according to Anderson. He says that out of hundreds of recent problems associated with clinical trials that were investigated by the government, only one was linked to a gene-related event: the death of the Arizona teen-ager, Jesse Gelsinger.
Is humanity facing a cure-all approach to treatment? Anderson tells WebMD researchers are working on it. "Not quite that completely, but the answer is yes -- but we're talking about 20, 30, 40 years. It is recognized that gene therapy will revolutionize medicine. But the problem is, we all got a bit carried away into thinking it was going to happen easily. Well, nothing major happens easily in nature.
"My feeling is for the next three to five years, all we're going to see is the occasional, little indication. I think we've got another five years of hard work before gene therapy really starts to become mainline."