The suicide gene therapy challenge: how to improve a successful gene therapy approach.

The transfer of a suicide gene into donor lymphocytes to control alloreactivity in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT) represents the widest clinical application of T-cell based gene transfer, as shown by more than 100 patients treated worldwide to date, several phase I-II studies completed, and a registrative phase III study, sponsored by a biotech firm, about to begin. In this mini-review, we will summarize the clinical results obtained to date, and attempt to identify the steps envisaged to optimize the suicide gene therapy approach.