Biomarin Pharmaceuticals (BMRN) said Tuesday that an experimental gene therapy targeting hemophilia A continued to help patients produce a protein enabling blood to clot. And while that will allow the company to seek accelerated approval in the U.S and Europe, data about Biomarin’s “one-and-done” treatment raise a big question: Do its effects last?
With gene therapy, a virus is used to insert genetic material to counter the effects of a disease. In hemophilia A, the most common form of the bleeding disorder, patients are missing a protein called factor VIII, which enables the blood to clot. The BioMarin treatment, valoctocogene roxaparvovec (for short: “valrox”), aims to enable patients to make their own factor VIII, so that they don’t need the extremely expensive drugs used to treat the disease.