Reaching positive milestones in gene therapy has been difficult since a highly publicized death in 1999,1 but some have succeeded. A major break came this year when researchers in Italy and Israel reported successfully treating two patients with ADA-SCID, a form of severe combined immunodeficiency that results from a defective gene for adenosine deaminase (ADA).2 In 2000--in the wake of gene therapy's darkest hour--a French group reported similar results for X-linked SCID, a form of the disease caused by a mutation in the common cytokine receptor gamma chain (gc).3 This Hot Paper, a culmination of years of work, may open the floodgates for therapies to come; the two patients, without further therapy, remain alive and well.
"There was a time that I think everyone in the field was feeling somewhat discouraged by just the difficulties of moving things forward to clinical trials," says pediatrics professor Kenneth Weinberg, Children's Hospital of ...
