[Updated 5/31/18, 10:13 a.m. See below.] A Vertex Pharmaceuticals partnership with CRISPR Therapeutics to test a genetically engineered therapy as a treatment for patients who have sickle cell disease has been dealt a setback.
The FDA placed a clinical hold on the application that Vertex (NASDAQ: VRTX) and CRISPR Therapeutics (NASDAQ: CRSP) submitted to start human studies, the companies announced Wednesday after the market close.
In a prepared statement, Vertex and CRISPR Therapeutics said that the clinical hold on CTX001 stemmed from “the resolution of certain questions that will be provided by the FDA as part of its review” of the investigational new drug application. The companies added that they expect to receive more information on those questions “in the near future” and they plan to work quickly with the regulator to resolve them. No other details were disclosed.
The sickle cell drug is part of a partnership that Vertex, based in Boston, and CRISPR Therapeutics, based in Switzerland, began in 2015. Vertex paid $105 million up front to use its partner’s gene-editing technology to develop new drugs. CTX001 is a gene-edited autologous hematopoietic stem cell therapy for patients suffering from beta thalassemia, an inherited disorder that affects hemoglobin in the blood, and sickle cell disease. The companies still plan to start a Phase 1/2 trial of the drug in Europe in adult patients in the second half of the year.
[Story updated to add analyst comment.] In a research note, JMP Securities analyst Liisa Bayko wrote that CTX001 is important to Vertex because it’s part of the company’s strategy of diversifying beyond cystic fibrosis drugs. JMP is not overly concerned about the FDA clinical hold because the drug remains on track for clinical testing in Europe, where the companies also plan to seek regulatory approval, she added.
“We are hopeful that this is a simple hiccup in development and we will keep an ear to the ground for updates on the clinical hold and the start of the EU study,” Bayko wrote.