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Commercial pressure has also pushed scientists to test gene treatments on human subjects as early as possible. No matter how promising a laboratory result is, clinical trials with real patients are more likely to pique Wall Street's interest. The risk is that expectations will be raised so high that the public--and investors--will lose faith in the technology when reversals occur. Flossie Wong-Staal, a molecular biologist at the University of California at San Diego, says that because "clinical trials, so far, have very little promise of curing patients," she prefers to think of her attempts to use gene therapy to boost the immune systems of AIDS patients as experiments rather than full-fledged clinical trials. Even if they do not lead to a marketable therapy, she notes, they are still valuable tools for guiding future investigations.
Nor are basic research and clinical trials mutually exclusive goals. "Humans are not big mice," says Dr. Ronald Crystal, who is working on gene therapy for cystic fibrosis at New York Hospital-Cornell Medical Center. "Unless we do clinical trials, we're never going to learn. You have to test it in the lab on animals, try it in humans and then go back to the lab. It's a cyclic process."
That process could still pay off. This week researchers led by Dr. Donald Kohn at Children's Hospital in Los Angeles will publish a report in Nature Medicine showing progress in using gene therapy to treat babies born with a disorder called adenosine deaminase deficiency. Three infants whose hereditary disorder leaves them defenseless against microbial attacks were given healthy genes using blood from their umbilical cords. Because the doctors were able to insert the good genes into the babies before their other immune defenses had fully formed, their bodies did not reject the material as foreign. Doctors do not claim to have cured the children, but, they note, the genes are "expressing."
It may turn out that a good strong dose of reality is just what gene therapy needed right now. The headiness of the early days has passed. And like cancer and aids researchers before them, gene therapists must learn to make medical progress the old-fashioned way--in fits and starts, with plenty of setbacks.
--Reported by David Bjerklie and Alice Park/New York