Catalyst Biosciences Awarded EU Patent for Experimental Hemophilia B Therapies

Vanessa Pataia avatar

by Vanessa Pataia |

Share this article:

Share article via email
EMA and Roctavian

Catalyst Biosciences has received a European Union patent for its investigational hemophilia B treatments, including its lead therapy candidate, dalcinonacog alfa (DalcA) and a preclinical gene therapy candidate called CB 2679d-GT.

“This newly issued EU patent expands the breadth of our Factor IX intellectual property portfolio. We now have broad patent coverage in all major markets including the United States, the European Union, Japan and China,” Nassim Usman, PhD, Catalyst’s president and CEO, said in a press release

Hemophilia B is a genetic disorder caused by mutations in the F9 gene that provides instructions for making FIX, a blood-clotting protein, which is produced in the liver and released into the bloodstream in an inactive form.

In healthy people, FIX is activated once there is an injury to a blood vessel and it plays a key role in the clotting process. However, in people with hemophilia B, the FIX protein is missing or faulty, which delays clotting and prolongs bleeding.  

DalcA is a recombinant human FIX — a lab-made version of FIX — intended to be used as a preventive treatment of bleeding episodes. DalcA can be given via a subcutaneous (under-the-skin) injection. This generally is considered less invasive than an intravenous (into-the-vein) injection, which is how many other FIX products are administered.

A Phase 2b clinical trial (NCT03995784) showed that DalcA was an effective and safe therapy to prevent bleeding in people with severe hemophilia B. The open-label trial enrolled six men with severe hemophilia B who received DalcA in one intravenous loading dose of 50 international units (IU)/kg, followed by daily subcutaneous injections of 100 IU/kg for 28 days.

Early results, presented by Catalyst at the 13th Annual Congress of the European Association for Haemophilia Allied Disorders earlier this year, showed the therapy steadily sustained FIX levels up to 27% after 14 days. In addition, no serious adverse side effects were reported by trial participants.

Final results from the trial are expected by June. 

Catalyst’s gene therapy CB 2679d-GT for hemophilia B works by using a harmless adeno-associated virus (AAV) as a vector to carry and deliver a healthy version of the F9 gene to the liver cells, so that a functional FIX protein can be produced. 

In preclinical studies using a mouse model of hemophilia B, CB 2679d-GT was found to perform better than another promising gene therapy for the disease, which uses a healthy version of the F9 gene called the Padua variant. CB 2679d-GT also resulted in a fourfold to fivefold shorter bleeding time in the mice, compared with the therapy using the Padua variant.

Catalyst recently optimized the AAV delivery vector used in the CB 2679d-GT therapy, resulting in higher FIX protein levels and more FIX protein activity in a mouse model of hemophilia B than the previous version of the therapy. This may allow for a lower dose as well as a tenfold or higher increase in protective FIX activity levels.

“DalcA has successfully completed a Phase 2b clinical trial and CB 2679d-GT is progressing into non-human primate studies. We believe that having both a potent recombinant SQ [subcutaneous] FIX and a best in class FIX gene therapy is the right strategy to build a hemophilia B portfolio,” Usman said.