Safety Considerations in Somatic Gene Therapy of Human Disease with Retrovirus Vectors

Somatic gene therapy of human disease with retrovirus vectors is a new technology with potentially important medical benefits. Although it involves recombinant DNA technologies and modified retroviruses, proper design of the vectors and delivery systems removes most potential foreseen risks. Furthermore, even in the very remote possibility that there is a nontherapeutic biological effect of the treatment, it is unlikely to be a harmful one. Thus, once very safe retrovirus vector–helper cell systems are constructed and in use, safety considerations should not hold up further human trials of retrovirus vectors. Safety is the primary issue that must be evaluated by the regulatory committees who have the responsibility for reviewing human gene therapy clinical protocols. Temin provides an overall view of the safety issues associated with retroviral-mediated gene transfer from the perspective of a pioneer in retrovirus biology.