MER511

MER511 is an investigational Fc biotherapeutic being developed by Merida Biosciences for the treatment of Graves' disease. Designed as an antibody-like therapeutic, it selectively targets and eliminates pathogenic autoantibodies that bind to thyroid-stimulating hormone receptors (TSHR) in the thyroid gland. MER511 functions by binding to these disease-causing autoantibodies and marking them for degradation through the body's natural clearance mechanisms, while simultaneously targeting the B cells responsible for producing these antibodies. This dual approach is intended to provide durable disease control by addressing the root cause of Graves' disease without inducing broad immunosuppression. As of 2025-2026, the drug is in Phase 1 clinical development, with a first-in-human study evaluating its safety, tolerability, pharmacokinetics, and immunogenicity in adults with Graves' disease via intravenous (IV) and subcutaneous (SC) administration.