After decades of research, in utero gene therapy nears first trial

SAN FRANCISCO — While Tippi MacKenzie was a postdoctoral fellow in the early 2000s, she and her lab mates experimented with using the then-new technology of gene replacement therapy to try to treat inherited disorders in mice before they were born. Over and over it worked. They cured mice with hemophilia and mice with tyrosinemia. And the whole time, people kept telling her that gene therapy in human fetuses was just around the corner, just five years away. 

It’s now been 25 years, and such a reality has yet to materialize. But after promising discussions with the Food and Drug Administration, MacKenzie is now closer than anyone’s ever been.

Her team has submitted an investigational new drug (IND) application to the agency seeking approval for a small trial that aims to treat five fetal patients with a rare lysosomal storage disorder. The agency told them they could bypass animal testing, because the safety profile of the vector they plan to use already has been so well characterized by other academics and companies developing gene therapies for kids and adults.