Shares in CRISPR Therapeutics plunged as much as 19 percent Wednesday after the company and partner Vertex Pharmaceuticals disclosed that the FDA placed a clinical hold on the investigational new drug application (IND) for CTX001 for the treatment of sickle cell disease. The drugmakers are developing the investigational ex vivo CRISPR gene-edited therapy under a 2015 deal.
In April, CRISPR and Vertex submitted an IND to the FDA to support the planned initiation of a Phase I/II trial in the US in adults with sickle cell disease. The companies noted Wednesday that they expect to shortly obtain additional information on questions from the agency and plan to work with the regulator toward a resolution.
“We’re working with the FDA and will respond as soon as we can about whatever questions they have regarding the trial,” added CRISPR spokesman Chris Erdman. According to CRISPR and Vertex, the planned initiation of a Phase I/II trial of CTX001 in Europe in adults with transfusion dependent β-thalassemia is unchanged, and the companies expect to initiate the study in the second half.
Commenting on the news, Robert W. Baird & Co. analyst Brian Skorney said “there’s so much promise with this technology, but it’s such early days.” Skorney added “it’s a permanent alteration of a patient’s genetic code so I think the FDA is going to be cautious.”