Eculizumab to Cemdisiran Switch in aHUS

Atypical Hemolytic Uremic Syndrome (aHUS) is a rare, lifethreatening, chronic disease of complement-mediated thrombotic microangiopathy (TMA) characterized by acute onset of renal impairment, thrombocytopenia, and microangiopathic hemolytic anemia. The estimated incidence of aHUS is approximately 0.5 per million per year. aHUS affects both adults and children, but is observed primarily in children and young adults. Atypical HUS commonly develops due to dysregulation of the alternative complement pathway and can be sporadic (80%) or familial(20%). The clinical course of aHUS is often unpredictable and can be dependent upon the specific genetic abnormality present within the complement system, if any, and/or triggering events associated with complement activation or inflammation, including autoimmune disease, transplant, pregnancy, infection, metabolic conditions, and drug use. In patients with dysregulated complement activity, such as those with complement mutations commonly observed in aHUS, the kidney vasculature is often the site of thrombosis stemming from endothelial injury. Cemdisiran has been designed to reduce the level of C5 mRNA in the liver, thereby reducing levels of circulating C5 protein, inhibiting terminal complement pathway activity, and preventing formation and deposition of the MAC (C5-b9) on endothelial cells in the kidney. As a result, complement-mediated endothelial cell damage in patients with aHUS and subsequent progression to End Stage Renal Disease (ESRD) may be reduced.