Human gene therapy.

Current concepts in gene transfer and its application to the treatment of human genetic disorders, cancer, and other diseases are discussed. Gene therapy is a technique in which a functioning gene is inserted into a human cell to correct a genetic error or to introduce a new function to the cell. Many methods, including retroviral vectors, have been developed for ex vivo and in vivo gene insertion into cells. Some pharmacists have likened gene therapy to a sophisticated form of drug delivery and have envisioned an active role for the pharmacy profession. There are several safety and ethical issues related to manipulating the human genome that need to be understood. Current gene therapy efforts focus on gene insertion into somatic (nongerminal) cells only. Gene therapy has the potential to revolutionize the treatment of genetic disorders, diseases associated with a genetic component (e.g., cystic fibrosis), cancer, AIDS, and many other diseases. Gene transfer may also be used to better understand the biology of disease processes, such as the source of relapse in bone marrow transplant patients. The human genome project will undoubtedly lead to the identification, characterization, and understanding of genes that are responsible for many human diseases, and gene therapy trials are sure to expand accordingly. To date, over 40 clinical trials have been approved and more than 110 patients have been entered in gene therapy studies. There are still many technical obstacles to overcome before gene therapy can have widespread application. Injectable vectors need to be developed to simplify foreign gene administration. Perhaps the biggest problem to overcome will be engineering the target cells to be able to regulate gene expression according to physiologic needs. Pharmacists should become knowledgeable about gene transfer techniques and possible clinical applications of gene therapy to keep abreast of the newest trends in medicine.