Spark Therapeutics has released new data about the hemophilia A treatment it is developing, saying that it substantially reduces bleeds, according to Stat News.
Spark, which has a US Food and Drug Administration-approved gene therapy for retinal dystrophy, has also been working on gene-editing-based treatment for hemophilia A to increase patients' factor VIII production, but as Stat News notes, data the company released in December was disappointing to investors.
The company now says that in a small study of 12 people, patients who received the highest treatment dose had their factor VIII production increase to 30 percent of normal and had no bleeds, Stat News reports. CNBC adds that Spark says the treatment also reduced the need for blood transfusions by 97 percent. However, it adds that two patients developed an immune response, sending one to the hospital.
This, CNBC reports, sent Spark's shares down about 30 percent. It adds that analysts were looking for a 30 percent or higher expression of factor VIII to call the trial a success, as long as there wasn't too much variability in the results.
"The totality of the data we're really pleased with and encouraged by, and it's driving our decision and plans to move into a phase 3 trial starting in the fourth quarter," Spark CEO Jeff Marrazzo tells CNBC.