Sutimlimab is a first-in-class monoclonal antibody in development for the treatment of cold agglutinin disease, a rare form of autoimmune haemolytic anaemia, caused by cold-reacting autoantibodies. These antibodies bind to red blood cell membranes and destroy them, leading to anaemia. Symptoms include chronic debilitating fatigue, acrocyanosis, shortness of breath and other anaemia-related symptoms, leading to a poor quality of life and increased health resource utilization. In chronic cold agglutinin disease, the patient is more symptomatic during winter months. Therapeutic options may range from using warm clothing and avoiding exposure to cold weather to blood transfusions and chemotherapy.
Sutimlimab takes a novel approach by binding to the cold-reacting autoantibodies and preventing them from attacking the red blood cells. Sutimlimab acts by selectively inhibiting one of the three complement pathways in the immune system leaving the other two pathways intact. This potentially preserves some of complement’s immune functions although it is unclear whether this would provide a clinical benefit and data from the clinical trials will be needed to better understand this. If approved, sutimlimab has the potential to become the first treatment option for cold agglutinin disease.
Avatrombopag is given as an oral tablet and works by mimicking the action of a hormone called thrombopoietin (TPO) which is responsible for causing pre-curser cells to mature into platelets. Avatrombopag binds to TPO receptors resulting in increased platelet production and increased platelet count. Results from clinical studies have demonstrated that avatrombopag is safe and efficacious. If licensed, avatrombopag could offer an additional treatment option for patients with chronic ITP who have had limited response to previous therapy.