Non-Technical Abstract 
2. Non-technical Abstract 
Rheumatoid Arthritis (RA) is a chronic, crippling disease which remains incurable and, in many 
cases, poorly treatable. The primary sites of disease are the joints where inflammation and tissue 
destruction lead to pain and disability. Chronic RA is also associated with a lower life expectancy. 
Because the medical control of RA remains inadequate joint replacement surgery remains the only 
reasonable option for many patients. We propose to break this stalemate by developing gene 
therapies for RA and other diseases of joints. Our basic strategy is to deliver therapeutic genes to a 
tissue known as the synovium, which lines all moveable joints. Once the genes are incorporated into 
the cells of the synovium (synoviocytes), these cells synthesize and secrete into the joint the anti- 
arthritic proteins encoded by the genes. In this manner, the joint now becomes the site of synthesis of 
its own anti-arthritic proteins. 
For the past five years we have been developing methods for delivering genes to joints, using 
the rabbit knee as a model system. This joint is approximately the same size as the human knuckle 
joint to be used in this clinical trial. Synovial tissue is surgically removed from the rabbits' knee joints 
and the synoviocytes grown outside the animal where the genes of interest are then transferred to the 
cells using a harmless, modified virus. The genetically modified cells are injected back into the knee 
joints of the donor rabbits where they continue to produce the proteins encoded by the transferred 
genes for several weeks. We have failed to find any toxicity associated with this procedure. 
We have devoted considerable attention to using a replication-defective retrovirus to deliver a 
gene encoding a potentially antiarthritic protein called the "interleukin- 1 receptor antagonist protein" 
(IRAP). IRAP protein is presently in human phase II clinical trials for the treatment of arthritis, 
where it is proving to be non-toxic and of some benefit. We have successfully removed samples of 
synovium from rabbits' knees, grown the cells contained within these samples and used the virus to 
incorporate the IRAP gene into the chromosomes of the rabbit synoviocytes. These genetically 
modified cells are then injected back into the knees of the recipient rabbits, where IRAP production 
continues for several weeks. This process provides protection against arthritis in these knees. 
We now propose to extend these methods to a human trial. Synovial tissue will be removed 
from human, rheumatoid joints at the time of scheduled joint replacement surgery. Cells will be 
grown outside the body in nutrient medium and infected with a modified retrovirus which not only 
carries the IRAP gene but also, as an additional safety measure, a gene encoding a viral protein 
known as "thymidine kinase" (tk). This renders the cells sensitive to the anti-viral agent ganciclovir, so 
that they may be easily eradicated if necessary. Modified cells will be injected into selected 
rheumatoid knuckle joints one week prior to normal, scheduled surgery to remove these joints and 
replace them with artificial joints. This provides a huge safety margin because the joints into which 
the genetically modified cells have been introduced will later be surgically removed during scheduled 
joint replacement procedures. Removal of the knuckle joints will remove all the experimental 
material, leaving the patient otherwise unaltered. 
At the time of surgery tissue will be retrieved and analyzed for the presence and expression of 
the transferred genes, and evidence of a biological response to IRAP. Patients will be monitored 
periodically after surgery and their blood cells tested for the presence of viral sequences. 
This trial represents a crucial first step towards the development of a safe, effective gene 
treatment for human RA. 
Recombinant DNA Research, Volume 19 
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