SOUTH SAN FRANCISCO, CA, USA I June 19, 2020 I Catalyst Biosciences, Inc. (NASDAQ: CBIO), today presented data from preclinical studies of its hemophilia B gene therapy CB 2679d-GT at the World Federation of Hemophilia Virtual Summit, taking place from June 14 -19, 2020.

The oral presentation, entitled: “Combination of a Novel Chimeric AAV Capsid and Potency Enhanced FIX Variant for Hemophilia B Gene Therapy,” given by Dr. Grant Blouse, senior vice president of translational research, provided preclinical results of CB 2679d-GT, the company’s novel FIX gene therapy. CB 2679d-GT was designed to achieve clinically relevant FIX levels at a reduced viral load by combining engineered AAV capsids with Catalyst’s novel high potency FIX transgene.

“The preclinical data from our constructs demonstrated a strong dose response and improved reduction in bleeding relative to the Padua variant,” said Nassim Usman, Ph.D., president and chief executive officer of Catalyst. “The enhanced FIX activity and reduced viral dose may offer advantages over current AAV-based gene therapies in clinical development.”

Studies of CB 2679d-GT in hemophilia B mice have demonstrated a 4-fold reduction in blood loss and an 8-fold reduction in bleeding time when compared with the same dose of the Padua variant of FIX. Furthermore, when packaged in a proprietary chimeric AAV capsid, CB 2679d-GT demonstrated a clear dose response of high stable FIX levels across the three dose levels in hemophilia B mice.

A pilot non-human primate study compared the expression and tolerability of CB 2679d-GT in the novel chimeric capsid KP1 with the LK03 capsid. The study demonstrated that CB 2679d-GT was well tolerated with high FIX expression that stabilized to approximately 25% to 50% FIX above baseline levels at the 6-week interim data cutoff. The novel chimeric capsid had differentiated and superior response to anti-capsid neutralizing antibodies than that observed for the LK03 comparator during the screening of non-human primates for the study.

A copy of the presentation slides can be accessed on the Events and Presentations section of the Catalyst website.

About Catalyst Biosciences
Catalyst is a research and clinical development biopharmaceutical company focused on addressing unmet needs in rare hematologic and systemic complement-mediated disorders. Our protease engineering platform includes development programs in hemophilia, a research program on subcutaneous (SQ) systemic complement inhibitors and a partnered preclinical development program with Biogen for dry age-related macular degeneration (AMD). One of our key competitive advantages is that the product candidates generated by our protease engineering platform have improved functionality and potency. These characteristics allow for improved dosing of our candidates including SQ systemic administration of recombinant coagulation factors and complement inhibitors, low-dose, high activity gene therapy constructs, and less frequently dosed intravitreal therapeutics. Our most advanced asset, SQ MarzAA has successfully completed Phase 2 development in prophylaxis, significantly reducing the annualized bleed rate (ABR) in individuals with Hemophilia A or B with inhibitors. Following regulatory guidance from the U.S. Food and Drug Administration and European Medicines Agency, we recently announced the design of a Phase 3 registration study that is planned for late 2020. Subcutaneous dalcinonacog alfa (DalcA) is being developed for the treatment of Hemophilia B and has demonstrated efficacy and safety in a Phase 2b clinical trial. We have a discovery stage Factor IX gene therapy construct – CB 2679d-GT – for Hemophilia B, that has demonstrated superiority compared with the Padua variant in preclinical models. Finally, we have a global license and collaboration agreement with Biogen for the development and commercialization of anti-complement Factor 3 (C3) pegylated CB 2782 for the potential treatment of geographic atrophy-associated dry AMD.

SOURCE: Catalyst Biosciences