Sutimlimab effectively prevented the exacerbation of hemolytic anemia in a patient with cold agglutinin disease (CAD) undergoing open-heart surgery, according to a new study published in the American Journal of Hematology.

The authors wrote that sutimlimab is potentially a new and safe option for patients with CAD undergoing major surgery.

“The current case demonstrates that even with a significant tissue trauma, acute phase reaction, and simultaneous shift in volume status, sutimlimab efficiently prevented complement activation,” they said.

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Sutimlimab is a monoclonal antibody and a selective inhibitor of complement C1s that blocks classical complement activation while leaving intact alternative and lectin pathways. It is currently being investigated in a clinical trial as a potential treatment for CAD.

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The team of researchers led by Sigbjørn Andreas Berentsen MD, PhD, speculated that sutimlimab may sufficiently block exacerbation of hemolysis through the classical complement pathway both during surgery and afterward.

Before undergoing coronary artery bypass grafting, the patient was treated with 6.5 g of sutimlimab infusion. The operation was conducted as warm heart surgery.

The authors reported that hemoglobin levels remained stable throughout the operation and that there were no signs of hemolysis. At routine follow-up 2 weeks later, the patient’s hemoglobin levels were stable and there were no signs of hemolysis.

Total complement activity was completely suppressed after sutimlimab infusion and remained so during follow-up, which indicated that the classical pathway was continuously and completely inhibited.

CAD is an autoimmune disease in which autoantibodies called cold agglutinins mistakenly attack red blood cells in cold temperatures. Special care must be taken if a patient with CAD has to undergo surgery. In case of cardiac disease, warm heart surgery must be performed.


Tvedt THA, Steien E, Øvrebø B, et al. Sutimlimab, an investigational C1s inhibitor, effectively prevents exacerbation of hemolytic anaemia in a patient with cold agglutinin disease undergoing major surgery. Am J Hematol. Published online November 14, 2021. doi:10.1002/ajh.26409