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W. French Anderson
cells? Will the new gene be expressed (that is, function) in the cells at an
appropriate level? Will the new gene harm the cell or the animal? These cri
teria are very similar to those required before use of any new therapeutic
procedure, surgical operation, or drug. They simply require that the new
treatment should get to the area of disease, correct it, and do more good
than harm.
A great deal of scientific progress has occurred in the nine years since that
paper was published. The technology does now exist for inserting genes into
some types of target cells.2 The procedure being used is called “retroviral-
mediated gene transfer.” In brief, a disabled murine retrovirus serves as a
delivery vehicle for transporting a gene into a population of cells that have
been removed from a patient. The gene-engineered cells are then returned
to the patient.
The first clinical application of this procedure was approved by the
National Institutes of Health [NIH] and the Food and Drug Administration
[FDA] on January 19, 1989.3Our protocol received the most thorough prior
review of any clinical protocol in history: It was approved only after being
reviewed fifteen times by seven different regulatory bodies. In the end it
received unanimous approval from every one of those committees. But the
simple fact that the NIH and FDA, as well as the public, felt that the proto
col needed such extensive review demonstrates that the concept of gene
therapy raises serious concerns.
We can answer our initial question, “What can we do now in the area of
human genetic engineering?” by examining this approved clinical protocol.
Gene transfer is used to mark cancer-fighting cells in the body as a way of
better understanding a new form of cancer therapy. The cancer-fighting cells
are called TIL (tumor-infiltrating-lymphocytes), and are isolated from a
patient’s own tumor, grown up to a large number, and then given back to
the patient along with one of the body’s immune growth factors, a molecule
called interleukin 2 (IL-2). The procedure, developed by Steven Rosenberg
of the NIH, is known to help about half the patients treated.4
The difficulty is that there is at present no way to study the TIL once they
are returned to the patient to determine why they work when they do work
(that is, kill cancer cells), and why they do not work when they do not work.
The goal of the gene transfer protocol was to put a label on the infused TIL,
2. See also W. French Anderson, “Prospects for Human Gene Therapy,”
Science,
26 Octo
ber 1984, 401-9; T. Friedman, “Progress towards Human Gene Therapy,”
Science,
16 June
1989 ,1275-81 .
3. J. Wyngaarden, “Human Gene Transfer Protocol,”
Federal Register
54 no. 47 (1989):
10508-10.
4. Steven A. Rosenberg
et al.,
“Use of Tumor-Infiltrating Lymphocytes and Interleukin-2
in the Immunotherapy of Patients with Metastatic Melanoma,”
New England Journal of Medi
cine
319, 25 (1988): 1676-80.