Acute heart failure with reduced ejection fraction following ozoralizumab in a patient with rheumatoid arthritis: A case report

Ozoralizumab (OZR), a novel next-generation tumor necrosis factor (TNF) inhibitor with variable heavy-chain domains of heavy-chain-only antibodies, named Nanobody®, was approved in September 2022 as the sixth TNF inhibitor in Japan. Other previous TNF inhibitors have been associated with various adverse drug reactions (ADRs), including heart failure (HF). The real-world data on these rare but clinically significant ADRs associated with OZR is lacking. Herein, we report a case of an 81-year-old female patient with rheumatoid arthritis who was insufficiently responsive to previous TNF inhibitors and developed HF with reduced ejection fraction (HFrEF) after the first OZR administration. Her condition improved after OZR discontinuation, suggesting that OZR may have precipitated the HF with reduced ejection fraction despite tolerance with previous TNF inhibitors. Further studies are warranted to elucidate the mechanism and incidence of OZR-associated HF.