Ozoralizumab: first Nanobody® therapeutic for rheumatoid arthritis

Introduction Ozoralizumab (Nanozora), a novel TNF inhibitor, was first approved in Japan in September 2022 as a next-generation antibody for the treatment of rheumatoid arthritis (RA). Ozoralizumab potently inhibits TNF action through two human TNFα-binding domains, and a human serum albumin-binding domain that prolongs its plasma half-life enabling 4-week administration intervals. Its molecular weight is 38 kDa, which is one-fourth that of the conventional immunoglobulin G.Areas covered Structural characteristics of ozoralizumab, preclinical findings, clinical data, and its recommended positioning in current RA treatments have been summarized.Expert opinion Studies using mouse models have shown the rapid distribution of ozoralizumab in inflamed joint tissues, presumably because of its small molecular size and albumin-binding action. In clinical studies, remarkable improvements in clinical symptoms and patient-reported outcomes were observed 2 days after subcutaneous administration of 30 mg ozoralizumab with concurrent methotrexate therapy. Moreover, the efficacy and tolerability of the drug for up to 52 weeks, with or without methotrexate, were confirmed. Ozoralizumab is expected to be a highly practical option for patients with RA as a new type of TNF inhibitor with early symptom improvement despite subcutaneous administration.