Catalyst Biosciences Announces CFI Variant Presentations at Two Upcoming Scientific Conferences

Catalyst Biosciences, Inc. (NASDAQ: CBIO) today announced that Grant Blouse, Ph.D., chief scientific officer, will present at two upcoming scientific conferences, the 5th Complement-based Drug Development Summit, being held October 26-28, 2021, and the American Society for Biochemistry and Molecular Biology’s (ASBMB) Serine Proteases in Pericellular Proteolysis and Signaling Virtual Meeting, being held October 28-30, 2021. Catalyst will provide an overview of the Company’s ProTUNE™ platform, and its ability to engineer Complement Factor I (CFI) for potency and specificity in complement-mediated disorders.

"We are excited that the ProTUNE™ platform and specifically the C3b/C4b degraders are demonstrating the potential to be used for precision medicine, in multiple complement-related indications,” said Grant Blouse, Ph.D., chief scientific officer of Catalyst. “We’re looking forward to providing additional updates on our complement discovery programs as well as on CB 4332, our enhanced CFI protease for CFI deficiency expected to enter the clinic in 2022.”

About Catalyst Biosciences, the Protease Medicines companyCatalyst is a research and clinical development biopharmaceutical company focused on addressing unmet medical needs in rare disorders of the complement and coagulation systems. Our protease engineering platform has generated two late-stage clinical programs, including MarzAA, a subcutaneously (SQ) administered next-generation engineered coagulation Factor VIIa (FVIIa) for the treatment of episodic bleeding in subjects with rare bleeding disorders. Our complement pipeline includes a preclinical C3-degrader program licensed to Biogen for dry age-related macular degeneration, CB 4332, an improved complement factor I protease for SQ replacement therapy in patients with CFI deficiency, proteases from our ProTUNE™ C3b/C4b degrader and ImmunoTUNE™ C3a/C5a degrader platforms designed to target specific disorders of the complement or inflammatory pathways, as well as other complement programs in development.

Forward-Looking StatementsThis press release contains forward-looking statements that involve substantial risks and uncertainties. Forward-looking statements include, without limitation, statements about the product candidates of Catalyst Biosciences, Inc. (the “Company”) and the benefits of its protease engineering platform; the potential markets for and advantages of the Company's complement product candidates, including C3b and C4b degraders; the ability of the ProTUNE™ platform to generate these or other product candidates; and the potential for C3b and C4b degraders to treat human disease, and expectations that CB 4332 will enter the clinic in 2022. Actual results or events could differ materially from the plans, intentions, expectations and projections disclosed in the forward-looking statements. Various important factors could cause actual results or events to differ materially, including, but not limited to, the risk that preclinical or clinical studies may be delayed as a result of COVID-19 and other factors, that C3b and C4b degraders are not yet in human clinical trials and will require additional manufacturing validation and pre-clinical testing before entering human clinical trials, the risk that human clinical trial will not replicate the results of studies in mice or other animals, competition, the requirement that the Company raise additional capital, and other risks described in the “Risk Factors” section of the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC") on March 4, 2021, on Form 10-Q filed with the SEC on August 5, 2021, and in other filings with the SEC. The forward-looking statements in this presentation represent the Company's view as of the date of this presentation and the Company does not assume any obligation to update any forward-looking statements, except as required by law.

Contact:

Ana KaporCatalyst Biosciences, [e-mail]