— Factor IX oral presentation & Factor VIIa poster presentation —

— Presentations to summarize the pharmacokinetics and activity of daily subcutaneous dosing in preclinical hemophilia models —

SOUTH SAN FRANCISCO, CA, USA I June 08, 2017 I Catalyst Biosciences, Inc. (Nasdaq:CBIO), a clinical-stage biopharmaceutical company focused on developing novel medicines to address hematology indications, today announced that data from two of its product candidates will be presented at the International Society on Thrombosis and Haemostasis (ISTH) Meeting being held in Berlin, Germany from July 8 to 13, 2017.

Catalyst is focused on the prevention of bleeding in individuals with hemophilia through the development of clotting factors that may be injected subcutaneously, rather than intravenously, potentially achieving normal coagulation activity.

Catalyst recently announced that CB 2679d/ISU304, its next-generation Factor IX variant, received a positive Orphan Drug Designation recommendation in the EU. Catalyst’s South Korean collaborator, ISU Abxis, plans to initiate a Phase 1/2 proof-of-concept study of CB 2679d in individuals with severe hemophilia B in June 2017 in South Korea.

The presentations being made by Catalyst are as follows:

Oral Presentation
Factor IX: CB 2679d/ISU304 is a next-generation coagulation Factor IX variant that is IND-approved in South Korea.

Title Pharmacokinetic and Activity Levels Achieved with Daily Subcutaneously Administered CB 2679d/ISU304 in Hemophilia B Dogs
Presenter   Howard Levy, M.B.B.Ch., Ph.D., M.M.M.
Session Future Biotherapeutics for Hemophilia A and B
Monday, July 10, 2017 at 10:00 am CET

Poster Presentation
Factor VIIa: Marzeptacog alfa (activated) is a next-generation Factor VIIa that successfully completed an intravenous Phase 1 clinical trial in severe hemophilia A and B with and without inhibitors. Catalyst plans to initiate a subcutaneous dosing efficacy study of marzeptacog alfa (activated) in individuals with hemophilia B with inhibitors in 2017.

Title:   Pharmacokinetics and Pharmacodynamics of Subcutaneously Administered 
  Marzeptacog Alfa (Activated) in Hemophilia B Mice, Levy et al.
  Tuesday, July 11, 2017 from 12:00-13:15 pm CET

About Factor IX
CB 2679d/ISU304 is a next-generation coagulation Factor IX variant that is IND-approved in South Korea. Catalyst believes that CB 2679d/ISU304 may allow for subcutaneous prophylactic treatment of individuals with hemophilia B. Learn more about Factor IX.

About Factor VIIa
Marzeptacog alfa (activated) is a high potency next-generation Factor VIIa that is initially being developed for the subcutaneous prophylactic treatment of severe hemophilia A and B patients with inhibitors. Learn more about Factor VIIa.

About Hemophilia and Factor Replacement Therapy
Hemophilia, for which there is no cure, is a rare but serious bleeding disorder that results from a genetic or an acquired deficiency of a protein required for normal blood coagulation. Individuals with hemophilia suffer from spontaneous bleeding episodes as well as substantially prolonged bleeding times upon injury. Learn more about hemophilia.

About Catalyst
Catalyst is a clinical-stage biopharmaceutical company focused on developing novel medicines to address hematology indications. Catalyst is focused on the field of hemostasis, including the subcutaneous prophylaxis of hemophilia and facilitating surgery in individuals with hemophilia. For more information, visit www.catalystbiosciences.com.

SOURCE: Catalyst Biosciences