2015 American Society of Gene and Cell Therapy Annual meeting in New Orleans, LA - Highlights - Long-term engraftment of zinc finger modified T-cells in HIV infection

Sangamo Biosciences (Richmond, CA, USA) presented novel clinical data regarding the SB-728-T-cell program for viral load control in chronic HIV infection. In this open-label phase 1 clinical trial, nine patients with low CD4+ T cell counts (200-500 cells/mm3) received 10-30 billion autologous, zinc finger nuclease modified CCR5 knockout T-cells.
Interestingly, modified T-cells were still detectable in the circulation after 3 years and generated long-lived T-memory stem cells. The authors demonstrated a sustained increase of CD4+ T cell counts in all treated subjects. T-memory stem cell count correlated with the decay of viral load.

Taken together, the SB-728-T-cell infusion unexpectedly resulted in very long term T-cell reconstitution, owing to the transformation of the zinc-finger edited T-cells to long lived memory stem cells. The program is now in Phase II, while a similar hemopoietic stem cell approach is already in phase I.