Report Sheds Light on X-SCID Gene Therapy Cancer Risk
In mouse study, one in three animals develop lymphoma after gene therapy
THURSDAY, April 27 (HealthDay News) -- Gene therapy for treatment of X-linked severe combined immunodeficiency syndrome (X-SCID), while largely successful, may cause T-cell leukemias because of the nature of the therapeutic gene rather than insertional mutagenesis, according to a brief communication in this week's issue of Nature.
Inder Verma, Ph.D., from The Salk Institute for Biological Studies in La Jolla, Calif., and colleagues used a mouse model of gene therapy for X-SCID. A healthy version of the IL2RG gene was inserted into diseased mice, and followed for much longer than previous studies -- about 1.5 years.
Thirty-three percent of the mice eventually developed T-cell lymphoma. The investigators suggest that lymphoma may have developed in the mice not because of insertional mutagenesis, but rather because IL2RG has multiple functions.
"Our results indicate that preclinical experimental treatments involving transgenes should include long-term follow-up before they enter clinical trials," the authors write. "Moreover, our findings highlight the need for continued development of vectors capable of regulated therapeutic gene expression."