Catalyst Biosciences Sells Complement Portfolio for $60 Million

Catalyst Biosciences, Inc. (NASDAQ: CBIO) today announced that it has signed a definitive asset purchase and sale agreement with Vertex Pharmaceuticals Incorporated (NASDAQ: VRTX) under which Vertex has acquired Catalyst’s portfolio of protease medicines that regulate complement, including CB 2782-PEG, for $60 million in cash.

Management Comments“We have been exploring strategic alternatives to monetize our assets and maximize value for our shareholders. This sale is part of the ongoing strategic process that we announced in February to explore alternatives and create value for shareholders. We have significantly reduced our cash burn and continue to work with our advisors to evaluate additional strategic alternatives for Catalyst,” said Nassim Usman, Ph.D., Chief Executive Officer of Catalyst Biosciences.

AdvisorsPerella Weinberg Partners acted as financial advisor to Catalyst and Orrick, Herrington & Sutcliffe LLP, and Potter Anderson & Corroon LLP served as legal advisors to the Company.

About Catalyst BiosciencesCatalyst is a biopharmaceutical company focused on protease therapeutics to address unmet medical needs in disorders of the complement and coagulation systems. After the transaction, Catalyst’s product candidates consist of the coagulation related assets marzeptacog alfa (activated) (“MarzAA”), dalcinonacog alfa (“DalcA”), and CB 2679d-GT. MarzAA is a SQ administered next generation engineered coagulation Factor VIIa (“FVIIa”) for the treatment of episodic bleeding and prophylaxis in subjects with rare bleeding disorders. DalcA is a next-generation SQ administered FIX. CB 2679d-GT is an AAV-based gene therapy construct harboring the DalcA sequence. Both MarzAA and DalcA have shown sustained efficacy and safety in mid-stage clinical trials and are available for partnering. CB 2679d-GT has obtained preclinical proof-of-concept and is also available for partnering.

Forward-Looking StatementsThis press release contains forward-looking statements that involve substantial risks and uncertainties. Forward-looking statements include, without limitation, those regarding potential uses of and markets for MarzAA, DalcAA and CB 2679-GT, and Catalyst’s plans to continue to explore strategic alternatives. 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 Catalyst will not be able to identify strategic partners interested in MarzAA, DalcAA, CB 2679-GT or any other transaction with the Company, 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 (the "SEC") on March 31, 2022, the Quarterly Report on Form 10-Q filed with the SEC on May 9, 2022, and in other filings filed from time to time with the SEC. The Company does not assume any obligation to update any forward-looking statements, except as required by law.

Contact:

Trisha ColtonCatalyst Biosciences, [e-mail]