Germ-line integration of gene therapy vectors

The National Institute of Health's Recombinant DNA Advisory Committee reported at a recent meeting that it has received notice of four cases in which sequences from gene therapy vectors have appeared in the ovaries or testes in animal studies.

FDA had reported at a Dec. 15, 1997 RAC meeting that it observed unexpected persistence of vector nucleic acid in gonadal tissue in multiple animal studies, raising the concern that gene vectors could lead to germ-line integration and pose unknown risks to patients in clinical trials.