CD377

CD377 is a novel **antiviral Fc-conjugate** designed for the **prevention and treatment of influenza A and B**. It is based on an engineered, highly potent **neuraminidase inhibitor** (targeting an essential enzyme on the influenza virus surface), chemically conjugated to the Fc domain of human IgG1, resulting in a molecule with both **direct antiviral activity** and immune system engagement via Fc receptor interactions. CD377 exhibits **multimodal mechanisms**: it directly inhibits viral replication and dissemination, and it also recruits antibody-dependent cellular immune responses (such as antibody-dependent cellular cytotoxicity and phagocytosis). In preclinical studies, CD377 showed superior efficacy compared to oseltamivir and zanamivir against both seasonal and pandemic influenza, offering protection in immune-competent and immunocompromised animal models. Its **long half-life** and high bioavailability after subcutaneous or intramuscular administration support infrequent dosing for prophylaxis and treatment. CD377 is being developed especially for use in patients at high risk or with immune deficiencies who may not benefit from vaccines. The drug is being developed by **Cidara Therapeutics** and is in preclinical development.