Nuvig Keystone Abstract May 2024.pdf

An Engineered Immunomodulatory IgG1 Fc Suppresses Autoimmune Inflammation

Through Pathways Shared With IVIG

Sunny L. Sneed 1o, Brian B. Reese¹, Ana F.S. Laureano¹, Sneha Ratnapriya¹, Isabella Fraschilla 2+, Kate L. Jeffrey 2#, Greg Coffey³, Pamela Conley³, and Robert M. Anthony 1*

1 Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129. 2 Center for the Study of Inflammatory Bowel Disease, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114. 3 Nuvig Therapeutics, 1775 Woodside Road, Suite 201, Redwood City, CA 94061, USA.

o Current address: Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA. + Current address: Koch Institute for Integrative Cancer Research at MIT, 77 Massachusetts Avenue; 76-453, Cambridge, MA 02139, USA. # Current address: Moderna Therapeutics, 200 Technology Square, Cambridge, MA 02139, USA.

Immunoglobulin G (IgG) antibodies in the form of high-dose intravenous immunoglobulin (IVIG) exert immunomodulatory activity and are used in this capacity to treat inflammatory and autoimmune diseases. However, due to high costs and recent global shortages of IVIG, alternative therapies are desirable in the clinic. Reductionist approaches have revealed that terminal sialylation of the single asparagine (N)-linked glycan at position 297 of the IgG1 Fc bestows anti-inflammatory activity, which can be recapitulated by introducing a F241A point mutation in the IgG1 Fc (Fc F241A ). Here, we examined the anti-inflammatory activity of CHO-K1 cell-produced Fc F241A in vivo in models of autoimmune inflammation and found protection to be independent of sialylation. On the other hand, sialylation markedly improved the half-life and bioavailability of Fc F241A via impaired interaction with the asialoglycoprotein receptor ASGPR. Further, Fc F241A suppresses inflammation through the same molecular pathways as IVIG and sialylated IgG1 Fc, requiring the murine C-type lectin SIGN-R1 and its human orthologue DC- SIGN in vitro and SIGN-R1 in vivo. This contrasts with Fc Abdeg (Efgartigimod), an engineered IgG1 Fc with enhanced neonatal Fc receptor (FcRn) binding, which reduces total serum IgG concentrations, independent of SIGN-R1. When co-administered, Fc F241A and Fc Abdeg exhibited combinatorial anti-inflammatory activity. Together, these results demonstrate that the anti-inflammatory activity of Fc F241A requires SIGN-R1, similar to high-dose IVIG and sialylated IgG1, and can be used in combination with other therapeutics that rely on divergent pathways, including Fc Abdeg, with enhanced therapeutic effects.