Safety of sickle cell disease therapy may not be certain, say FDA scientists

In  briefing notes released ahead of a key meeting on Tuesday, scientists at the US Food and Drug Administration describe uncertainty in the risks associated with a new gene editing technology.

The advisory panel is meeting to discuss a submission from US biotech Vertex Pharmaceutical (Nasdaq: VRTX) and Swiss gene editing specialist CRISPR Therapeutics (Nasdaq: CRSP) for exagamglogene autotemcel (exa-cel).

A CRISPR/Cas9 gene-edited therapy, exa-cel works by editing a patient's own stem cells to produce high levels of fetal hemoglobin in red blood cells.