FDA Advisory Committee Recommends Resumption of One of Three Suspended Gene Therapy Experiments

An FDA advisory committee on Friday recommended that two of three recently suspended gene therapy experiments resume only when patients do not respond to other "reasonable alternatives," such as bone marrow transplants, the Baltimore Sun reports (O'Brien, Baltimore Sun, 3/5).

FDA has temporarily suspended three U.S. gene therapy experiments for severe combined immunodeficiency disease after news that a third child in a similar French study has developed leukemia. Seventeen French patients with X-linked SCID have received a treatment that uses a modified mouse leukemia virus to replace a defective gene with a healthy one.

Although most of the patients have experienced improvement in their conditions, three have developed leukemia within several years of treatment, and one has died from the disease. Concern increased last month when the National Heart, Lung and Blood Institute reported that one of 42 monkeys that have received the same gene treatment has died of cancer (California Healthline, 3/4).

The FDA Cellular, Tissue and Gene Therapies Advisory Committee recommended that gene therapy experiments at NIH and the University of Southern California remain suspended but said that second study at USC for a different form of SCID should continue.

"The additional data hasn't suggested that there is a heightened risk, but we have to be careful," Mahendra Rao, chair of the committee, said.

Committee members said that, in many cases, bone marrow transplants can serve as effective alternatives to gene therapy for patients diagnosed with SCID early (Baltimore Sun, 3/5). However, committee members said that patients who do not respond to alternative treatments should have access to gene therapy (AP/Washington Post, 3/5).

FDA officials have set no schedule for when the agency might act on the recommendations from the committee (Baltimore Sun, 3/5).

NPR's "All Things Considered" on Friday reported on the FDA suspension of the gene therapy experiments. The segment includes comments from Cynthia Dunbar of NHLBI, Harry Malech of the National Institute of Allergy and Infectious Diseases and Jennifer Puck of the National Human Genome Research Institute (Palca, "All Things Considered," NPR, 3/4). The complete segment is available online in RealPlayer.