Catalyst Biosciences Announces Emergence from Key

-- European Patent Office indicates that no opposition to Catalyst’s patent has been filed --

-- INC Research selected as CRO for Phase 2/3 efficacy clinical trial of Factor VIIa, marzeptacog alfa (activated); trial expected to commence in the fourth quarter of 2017 --

SOUTH SAN FRANCISCO, Calif., March 30, 2017 (GLOBE NEWSWIRE) -- Catalyst Biosciences, Inc., (NASDAQ: CBIO ) a clinical-stage biopharmaceutical company focused on developing novel medicines to address hematology indications, today announced receipt of notice from the European Patent Office that the opposition period for a patent granted to Catalyst has expired and no opposition has been filed.

The patent, entitled "Factor VII polypeptides that are modified and uses thereof" (European patent EP 2679678), is part of the Company's intellectual property portfolio surrounding its improved next-generation coagulation Factor VIIa, marzeptacog alfa (activated). Catalyst’s Factor VIIa patent portfolio consists of 62 issued patents worldwide including, but not limited to, patents in the United States, the European Union, China and Japan.

"Emergence from the European Patent Office’s opposition period adds additional protection to our Factor VIIa program which we believe has long-term market exclusivity through at least 2029 in key markets," stated said Nassim Usman, Ph.D., Catalyst’s President and Chief Executive Officer.

In addition, the Company announced it has selected INC Research (Nasdaq: INCR ), a global contract research organization (CRO) to conduct the Phase 2/3 clinical trial of marzeptacog alfa (activated) in individuals with hemophilia A & B with inhibitors.

Dr. Usman added, "We are also very pleased to partner with INC Research given their proven track record in executing high-quality hemophilia clinical trials, and remain on track to initiate the Phase 2 part of a Phase 2/3 subcutaneous efficacy trial of marzeptacog alfa (activated) in the fourth quarter of 2017.”

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, 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 marzeptacog alfa (activated) and development plans for this product candidate are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to the duration of patent coverage and potential market exclusivity for marzeptacog alfa (activated), Catalyst’s clinical trial timelines, including the anticipated initiation clinical trials in 2017, the potential uses and benefits of subcutaneously dosed marzeptacog alfa (activated), and the potential for marzeptacog alfa (activated) to allow for subcutaneous prophylactic treatment of individuals with severe hemophilia A and B with inhibitors. 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 studies may be delayed and may not have satisfactory outcomes, that human trials will not replicate the results from animal 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 and S-1 filed with the SEC. 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