 CRISPR Therapeutics Inc. CRSP, 7.21 and Vertex Pharmaceuticals Inc. VRTX, 3.04 said Tuesday that the Food and Drug Administration granted a rolling review to the exagamglogene autotemcel, the therapy the companies are developing to treat sickle cell disease and transfusion-dependent beta thalassemia. CRISPRs stock was up 3.1 in premarket trading on Tuesday, while Vertex shares gained 1.1. 