Mogamulizumab is a humanized, glycoengineered IgG1κ monoclonal antibody that targets CC chemokine receptor 4 (CCR4), a G protein-coupled receptor expressed on regulatory T cells (Tregs) and Th2 cells. Its Fc region is engineered to enhance antibody-dependent cellular cytotoxicity (ADCC). By binding to CCR4, mogamulizumab selectively depletes CCR4-expressing T-cell subsets, particularly Tregs that suppress anti-tumor immunity. It is approved for the treatment of mycosis fungoides (MF) and Sézary syndrome (SS), two subtypes of cutaneous T-cell lymphoma (CTCL), in adult patients who have received at least one prior systemic therapy. It is administered via intravenous infusion.