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Catalyst Biosciences and Mosaic Biosciences Enter into Strategic Collaboration to Develop Intravitreal Anti-Complement Factor 3 (C3) Products for the Treatment of Dry AMD and Other Retinal Diseases

October 24, 2017

Collaboration aims to develop best-in-class anti-C3 intravitreal products with quarterly dosing frequency and better potency

C3 is a clinically validated target in dry age-related macular degeneration, a large multi-billion-dollar market with no approved therapies

SOUTH SAN FRANCISCO, Calif. and BOULDER, Colo., Oct. 24, 2017 (GLOBE NEWSWIRE) -- Catalyst Biosciences, Inc. (Nasdaq:CBIO), and privately held Mosaic Biosciences, Inc., today announced that they have entered into a strategic collaboration to develop Catalyst’s anti-C3 protease assets for dry age-related macular degeneration (dAMD) and other serious inflammatory retinal disorders. Catalyst’s current anti-C3 protease compounds are selective for C3 and have been shown to completely inhibit C3 in preclinical studies with good tolerability after intraocular administration.

Under terms of the agreement, Catalyst and Mosaic will collaborate to improve the pharmacokinetic (PK) properties of Catalyst’s anti-C3 proteases, with a goal of delivering product candidates that have a target profile of a once quarterly intravitreal (IVT) dosing in humans and better potency compared with competitors. Catalyst and Mosaic will co-fund the research; Catalyst will retain global commercial rights for all collaboration products and Mosaic will receive product sublicense fees and/or milestone payments and royalties.

“Inhibiting C3 in the complement pathway has recently been validated for the treatment of Geographic Atrophy (GA), a late-stage form of dAMD. However, the current frequency of IVT drugs in development is not ideal for patients with chronic ocular diseases,” said Nassim Usman, Ph.D., President and CEO of Catalyst Biosciences. “Mosaic will apply its ophthalmology expertise, research team, proprietary protein engineering and sustained release technology to our anti-C3 protease lead molecule to develop a clinical candidate with the desired target profile. This collaboration agreement allows Catalyst to advance its anti-complement assets and explore potential licensing opportunities while maintaining its strategic focus on our clinical hemophilia programs.”

Eric Furfine, Ph.D., who led preclinical development for Regeneron’s Eylea™ and was Chief Scientific Officer for Eleven Biotherapeutics’ ocular protein programs, and is now leading Mosaic’s ophthalmology efforts, commented, “We believe that there is a clear mechanistic advantage to Catalyst’s enzymatic approach to inhibiting C3 activity compared with an antibody or peptide approach. Our modeling and experience predict that by modifying Catalyst’s lead compounds, we can develop best-in-class anti-C3 products with at least quarterly IVT dosing.”

About Anti-Complement and Catalyst’s Anti-C3 Proteases
The human complement system is a complex series of biological processes and cascades that are regulated naturally by proteases. Activation of the complement system occurs in ocular diseases such as age-related macular degeneration (AMD), producing substantial inflammatory tissue damage. Catalyst's anti-complement program is directed at complement factor 3 (C3), a pharmaceutical target at the nexus of the complement system and common to all three pathways of activation. Recent clinical results with monthly IVT dosing regimens have validated C3 as a target for Geographic Atrophy, which is the late stage of dry AMD. Catalyst’s anti-C3 protease leads have been shown to completely inhibit C3 in the vitreous after IVT administration in non-human primates.

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

About Mosaic
Mosaic Biosciences is private biotechnology company that is advancing a highly versatile and fundamentally new class of biomaterials based on engineered proteins and synthetic polymers.  Mosaic’s technology platform provides the leading biomaterial for cell- and protein-therapeutic delivery, regenerative medicine, and tissue sealants.  For more information, please visit

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 collaboration with Mosaic Biosciences, the potential development of anti-C3 product candidates and their potential uses and benefits are forward looking statements. 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 that we and Mosaic are unable to develop suitable anti-C3 product candidates, that we will not be able to license any such candidates, if developed, and other factors described in the “Risk Factors” section of the Company’s most recent Quarterly Report on Form 10-Q filed with the SEC on August 3, 2017. Catalyst does not assume any obligation to update any forward-looking statements, except as required by law.


Fletcher Payne
CFO, Catalyst Biosciences

Andrew McDonald, Ph.D.
LifeSci Advisors

Josephine Belluardo, Ph.D.
LifeSci Public Relations

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Catalyst Biosciences, Inc.Mosaic Biosciences, Inc.