Financial Milestone Achieved in Catalyst’s Subcu

SOUTH SAN FRANCISCO, Calif., July 06, 2017 (GLOBE NEWSWIRE) -- Catalyst Biosciences, Inc. (Nasdaq: CBIO ), a clinical-stage biopharmaceutical company focused on developing novel medicines to address hematology indications, today announced that it has achieved a financial milestone under its collaboration with ISU Abxis. In June of 2017, the first patient and cohort were enrolled in a Phase 1/2 proof-of-concept clinical trial in individuals with severe hemophilia B, which triggered the milestone payment to Catalyst. The clinical trial will evaluate Catalyst’s next-generation Factor IX variant, CB 2679d/ISU304, for subcutaneous prophylaxis. ISU Abxis and Catalyst plan to have top-line data from the clinical trial by the end of 2017.

As previously announced, ISU Abxis has completed dosing of the first cohort of up to five patient cohorts in the clinical trial. The trial will include single intravenous and subcutaneous dosing cohorts, followed by daily subcutaneous injections of CB 2679d/ISU304.

“We are pleased to have achieved another financial milestone with the Factor IX clinical program, but for us the highlight of the Factor IX program has been the rapid patient enrollment in the clinical trial to date,” said Nassim Usman, Ph.D., President and Chief Executive Officer of Catalyst. “We want to prevent bleeding in individuals with hemophilia B and we look forward to results later this year that may determine whether CB 2679d/ISU304 can achieve sustained normalization of Factor IX activity with subcutaneous dosing.”

Catalyst has a collaboration with ISU Abxis to advance the development of CB 2679d/ISU304 through the Phase 1/2 proof-of-concept clinical trial in individuals with hemophilia B. After Phase 1/2, ISU Abxis has an option for exclusive commercial rights in South Korea and a profit share on ex-South Korean commercialization. Catalyst retains full development and commercial rights for CB 2679d/ISU304 outside of South Korea.

About Factor IX CB 2679d/ISU304 is a next-generation coagulation Factor IX variant that is being evaluated in a Phase 1/2 proof-of-concept clinical trial 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 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, please visit www.catalystbiosciences.com .

Forward-Looking Statements This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statement of historical facts, included in this press release regarding our strategy, the potential uses and benefits of CB 2679d/ISU304 and development plans for this product candidate are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to Catalyst’s clinical trial timelines, including the anticipated completion of a Phase 1/2 proof-of-concept study for CB 2679d/ISU304 or the plans to disclose results from the Phase 1/2 study by the end of 2017, and the potential uses and benefits of subcutaneously dosed CB 2679d/ISU304. Actual results or events could differ materially from the plans and expectations and projections disclosed in these forward-looking statements. Various important factors could cause actual results or events to differ materially from the forward-looking statements that Catalyst makes, including, but not limited to, the risk that trials and enrollment may be delayed and may not have satisfactory outcomes, that human trials will not replicate the results from preclinical studies, that potential adverse effects may arise from the testing or use of Catalyst’s products, including the generation of antibodies, the risk that costs required to develop or manufacture Catalyst’s products will be higher than anticipated, competition, and other factors described in the “Risk Factors” section of the Company’s most recent Annual Report on Form 10-K filed with the SEC on March 8, 2017. Catalyst does not assume any obligation to update any forward-looking statements, except as required by law.

Contacts: Investors: Fletcher Payne, CFO, Catalyst Biosciences 650.871.0761 investors@catbio.com Media: Denise Powell 510.703.9491 denise@redhousecomms.com