Orthopaedic applications of gene therapy: From concept to clinic

Gene therapy offers new possibilities for the clinical management of orthopaedic conditions that are difficult to treat by traditional surgical or medical means. To bring the potential of this novel technology into the clinic, a research program was initiated that aimed to identify orthopaedically useful genes and develop methods for delivering them to suitable sites under conditions in which gene expression remains at therapeutic levels for the appropriate periods of time; this program is now 10 years old. Rheumatoid arthritis was selected as the lead disease. Preclinical studies evaluating the local and systemic delivery of numerous different genes by in vivo and ex vivo methods in murine and lapin models led to the development of a human gene therapy protocol for arthritis. In this protocol, a gene encoding the human interleukin-1 receptor antagonist protein is transferred to the metacarpophalangeal joints of female patients with rheumatoid arthritis. The first patient was treated this way in July 1996. This is not only the first orthopaedic application of human gene therapy, but also the first use of gene therapy approved for a nonlethal disease. In addition to providing additional therapeutic options for the treatment of rheumatoid arthritis, the experimental data from this study suggest that gene transfer approaches may improve the treatment of osteoarthritis, the repair of cartilage, ligaments, tendons, menisci, intervertebral discs and bone, and the management of disorders such as osteoporosis and osteogenesis imperfecta. They also show promise as a means for developing novel and improved animal models of orthopaedic diseases. If the current rate of progress continues, wide clinical application of gene therapy in various orthopaedic indications should occur within the next 5 to 10 years.