LAUSR

Cold agglutinin disease (CAD) is a rare autoimmune haemolytic anaemia (AIHA), which leads to fatigue and acrocyanosis.1– 4 Until recently, treatment of CAD was mainly based on reduction of the Bcell clone by rituximab or chemoimmunotherapy. While rituximab has a slow onset of action and variable efficacy with frequent relapses,2 chemoimmunotherapy may be accompanied by pronounced toxicity.5 Patients may still remain transfusiondependent, which may lead to alloimmunisation or iron overload.6 Sutimlimab, a monoclonal antibody targeting the C1s protein of the classical complement pathway, effectively reduced haemolysis, increased haemoglobin levels and reduced fatigue in prior studies.7– 9 In this openlabel trial, we evaluated the safety and efficacy of longterm sutimlimab in four patients with CAD. The protocol was approved by the Ethics Committee of the Medical University of Vienna and the trial was conducted according to the principles set forth in the Declaration of Helsinki. The trial was conducted between December 2017 and March 2021 at the Medical University of Vienna. Following the firstinhuman trial10 and participation in a named patient programme,9 four patients with CAD resumed treatment with sutimlimab every 2 weeks as Received: 18 March 2022 | Accepted: 18 May 2022