Errant became the first entity to pass the U.S. Food and Drug Administration Recombinant DNA Committee for gene therapy in sickle cell disease and beta thalassemia in 2007. The company was also the first to get orphan drug designation for thalassemia in the U.S. and Europe and to produce a commercial batch (eight to 10 patients) of gene therapy for sickle cell disease and thalassemia.

The company's delivery vector uses the natural wildtype beta globin gene, which has been used to treat four patients with no incidence of safety factors. San Rocco also aims for a one-time treatment price of $700,000, which will be lowered as more patients are treated. This is much lower compared to other similar gene therapies, which can cost as much as $1.8 million.