Experimental Treatments for Cold Agglutinin Disease
APL-2 is a synthetic peptide (a small protein) that binds and blocks the C3 and C3b proteins of the complement system. The complement system consists of three parts: the classical, alternative, and lectin pathways. C3 and C3b are involved in all three pathways, so blocking them inhibits the entire complement pathway. A Phase 3 trial is planned to launch soon.
Eculizumab is a first-in-class monoclonal antibody being investigated for the treatment of hemolytic anemia in CAD patients. It binds to the complement protein C5 and prevents its activation, preventing inflammation and cell lysis (disintegration). Results of a Phase 2 trial showed that eculizumab was well tolerated and lessened hemolysis and transfusion requirements in patients with CAD.
Rituximab works by reducing harmful antibodies that attack immune cells. Bendamustine is a chemotherapeutic agent that interferes with DNA synthesis and prevents the proliferation of cells, including immune cells. For patients who do not respond to management methods like warming, the combination of these two therapies to slow down the immune system may be useful. A completed Phase 2 trial showed promising results.
Sutimlimab is being developed to treat hemolysis in patients with CAD. It works by selectively blocking the activity of C1 — a protein with a central role in the classical complement pathway, which is overly active in CAD, leading to hemolysis and anemia. Positive Phase 3 results have been reported, and it is now under review for approval by the U.S. Food and Drug Administration.