Once the NIH physicians treated their tiny patient in 1990, researchers rushed to get into the game with human trials. At the halfway point in the decade, the field was not progressing well. Then-NIH Director Harold Varmus, M.D., himself critical of the gene therapy trials in people, created a committee to review NIH's investment in the field. Varmus wanted to know whether NIH should continue to invest so heavily in the new technology. While they saw promise, they also saw challenges.
Significant problems remain in all basic aspects of gene therapy.
Major difficulties at the basic level include shortcomings in all current gene transfer vectors and an inadequate understanding of the biological interaction of these vectors with the host. First, they must isolate the disease-related gene. Then it must be packaged in a vector, usually a disabled virus that cannot reproduce and cause disease, but that can act like a delivery truck to transport the gene inside the patient's cells. Once inside the body's cells, the new gene can begin to function and restore health. But building an effective delivery truck hasn't been easy.