Gene therapy (and stem cell) triumph – at last

After many years of slow progress and some highly publicized setbacks, gene therapy finally seems to have its first major success, reported this week in the New England Journal of Medicine.

Gene therapy uses genetic techniques to insert genes into a person that correct a genetic disease. For example, a “fixed” version of a flawed gene can be inserted, with the hope that the fixed gene can somehow take hold and provide a cure. The problem has long been that, even if you can create cells with corrected versions of the gene, inserting those cells into a person leads to, at best, just a temporary fix. The cells eventually die and the person is back to where they started. Creating a long-lasting cure has been elusive, until now.

In this new study, Alessandro Aiuti and colleagues (from the University of Milan and other institutions) are using gene therapy gene to treat severe combined immunodeficiency (SCID), a usually fatal disorder in which the immune system is severely crippled by the lack of an enzymme called adenosine deaminase (ADA). Children with SCID are sometimes called “bubble children” because they have to live in a sealed environment to prevent infections.

Aiuti et al. created bone marrow stem cells (the cells that produce blood cells) for the SCID children in which the ADA gene was fixed. They then injected these cells back into the children, and hoped that the cells would “take”; i.e., that they would become stable parts of the children’s bone marrow. So far (the trial isn’t yet over), 8 out of 10 children have had successful results: their blood cells are producing ADA on their own, and they don’t have life-threatening side effects. More important, these children can now lead a normal life – they don’t have to live in a “bubble.”

These results are still preliminary, but they look very, very encouraging. Let’s hope this is just the first of many successful gene therapy and stem cell therapy cures.