SAR-443809 

SAR-443809 is a selective alternative complement system inhibitor and monoclonal antibody targeting complement factor Bb. SAR-443809 blocks the cleavage of C3 and factor B by selectively binding to the activated form of factor Bb, with a K_D of 7.3 nM for human factor Bb. SAR-443809 inhibits the amplification loop of the alternative complement pathway and C3 activation, reduces C3b deposition, and blocks the activation of pathways associated with intravascular and extravascular hemolysis. SAR-443809 can be used for the research of hematological and renal disorders mediated by abnormal alternative complement pathway^[1].

Human

SAR-443809 (Human FB: 6-500 nM; human FBb: 0.4-30 nM; SAR443809 Fab: 3.7-300 nM; 25°C during assay) binds with high affinity to human factor Bb (K_D = 7.3 nM) and cynomolgus factor Bb (K_D = 61 nM), and its Fab fragment binds to the active alternative pathway C3 convertase (C3bBb) with high affinity (K_D = 0.5 nM)^[1].
SAR-443809 potently and selectively inhibits the human complement alternative pathway (IC₅₀ = 8.47 μg/mL) and cynomolgus monkey complement alternative pathway (IC₅₀ = 15.72 μg/mL) by blocking cleavage of C3 and factor B, without inhibiting the classical or lectin pathways^[1].
SAR-443809 (50 minutes at 37°C) inhibits alternative pathway-mediated hemolysis of rabbit erythrocytes with an IC₅₀ of 28.45 μg/mL^[1].
SAR-443809 (50 minutes at 37°C) inhibits alternative pathway-mediated C3b deposition on rabbit erythrocytes with an apparent IC₅₀ of 33.8 μg/mL^[1].
SAR-443809 (100 μg/mL; 30 minutes at 37°C) inhibits unregulated fluid-phase C3 cleavage in factor H-depleted human serum, preventing consumption of C3 via alternative pathway tickover^[1].
SAR-443809 selectively binds to human factor Bb (EC₅₀ = 30.9 ng/mL) and shows no specific binding to other tested plasma serine proteases, including most complement system enzymes^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

SAR-443809 (15 mg/kg; i.v./s.c.; single dose) delivers sustained (≥ 288 hours) 90% inhibition of complement alternative pathway activity in female cynomolgus monkeys ^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

629  [NCBI]

AAH04143.1

Complement Factor B/CFB

ELISA, FACS, Functional assay

Unconjugated

The product can be reconstituted/diluted with sterile PBS or saline.

Please refer to the lot-specific COA for specific buffer information.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Rajagopal V, et al. SAR443809: a selective inhibitor of the complement alternative pathway, targeting complement factor Bb. Blood Adv. 2023;7(16):4258-4268.