RLYB331

RLYB331 is a monoclonal antibody that acts as an inhibitor of Matriptase-2 (MTP-2, also known as TMPRSS6), a serine protease involved in the regulation of hepcidin formation and iron homeostasis. By inhibiting MTP-2, RLYB331 increases hepcidin levels, decreases iron overload, and addresses ineffective erythropoiesis. The drug is being developed for the treatment of severe anemias with ineffective erythropoiesis and iron overload, including beta thalassemia and certain subtypes of myelodysplastic syndromes. Originally developed by Kymab (as KY1066) and later acquired from Sanofi by Rallybio, it remains in preclinical development[1][3][5][7].