Gene therapy as currently known began in the United States of America in 1989 when cancer patients were treated with tumour-infiltrating lymphocytes transduced with a marker gene to track in vivo distribution. The first therapeutic trial about a year later involved the treatment of children suffering from an inherited immunodeficiency disease called adenosine deaminase deficiency (ADA). Recently, the first cure by gene therapy was effected in newborns suffering from the rare Severe Combined Immunodeificency type X-1 (SCID-X1) and at least four SCID-X1 babies have been reported to have reconstituted their immune systems. Gene transfer medicinal products have also been used for DNA vaccines.

The WHO Clinical Gene Transfer Monitoring Group is an international group of experts from France, Germany, Netherlands, Republic of Korea, United Kingdom, and United States of America convened under the auspices of WHO. The Group is working on development of a general definition of gene transfer medicinal products. Its objectives will be to monitor development in clinical gene transfer, consider nomenclature for gene therapy products, provide advice to the WHO INN Expert Group, and consider development of an appropriate WHO guideline. More information is available at: http://www.who.int/biologicals/