[Corrected, 10/11/18, 11:12 a.m.] The FDA has lifted its hold on a clinical trial for a genetically engineered treatment for sickle cell disease, and CRISPR Therapeutics and Vertex Pharmaceuticals say they plan to start a Phase 1/2 study in the U.S. and Europe by the end of the year. Enrollment is already underway for a clinical trial in Europe testing the treatment in another disorder, beta thalassemia. [Description of clinical trials corrected.]
In May, partners CRISPR Therapeutics (NASDAQ: CRSP) and Vertex (NASDAQ: VRTX) halted their U.S. plans to test their drug, CTX001, in sickle cell disease. At the time of the clinical hold, the companies said that the FDA had additional questions as part of its review of the paperwork that companies submit for permission to start a clinical trial.
On Wednesday, Switzerland-based CRISPR Therapeutics and Vertex, headquartered in Boston, said that the FDA’s clinical hold for tests of the experimental therapy in sickle cell disease was lifted and the application to begin clinical trials had been accepted. The partners offered no details on what questions the FDA asked or how they were answered. But with the FDA hold lifted, the clinical study of CTX001 could become the first U.S. trial testing a therapy developed with CRISPR gene editing. A Vertex spokeswoman declined to say when the companies expect to start dosing patients with the experimental drug.
The partners also noted that their therapy is making progress outside of the U.S. They announced that they have received regulatory clearance in “multiple countries” to begin tests of the experimental treatment in both sickle cell disease and beta thalassemia, an inherited disorder that affects hemoglobin in the blood. A Phase 1/2 study in Europe is enrolling beta-thalassemia patients who depend on blood transfusions to treat their disorder.
CTX001 emerged from a drug development alliance that CRISPR Therapeutics and Vertex began in 2015. The partners started working on treatments for cystic fibrosis, an area of specialization for Vertex. Blood disorder treatments were also included in the research pact. CTX001 is made by taking a patients hematopoietic stem cells and applying the Swiss company’s gene-editing technology. Those stem cells are engineered to produce high levels of fetal hemoglobin in red blood cells, which is intended to ease the need for blood transfusions in beta-thalassemia patients, as well as alleviate the problems experienced by sickle cell patients.
Under the drug partnership, Vertex has the rights to license up to six new treatments developed with the CRISPR-Cas9 gene-editing technology. The companies are sharing equally in research and development expenses, and they will also share the profits of any commercialized therapies that emerge from the partnership.