Investigational drugs in sickle cell anemia

Sickle cell anemia is one of the most common autosomal recessive diseases in the world. Patients with sickle cell anemia have variable penetrance and it is hard to predict the risk and timing of complications. It is characterized by a point mutation in the beta-globin gene (GAG --> GTG) and the production of hemoglobin S. The latter leads to decreased deformability of the red blood cells (RBCs) that adhere to endothelia cells culminating in vascular occlusion and its sequelae of tissue ischemia and organ damage. Moreover, sickled RBCs undergo intravascular hemolysis and accelerated erythropoesis. The hallmarks of this disease are shortened RBC survival and vaso-occlusive crises. For the past ten years, the pathophysiology of this disease has been better elucidated and has led to significant improvements in the standard of care. Vaso-occlusion is now understood to be a complex event that involves abnormal interactions between RBCs, leukocytes, endothelial cells and the coagulation pathways. The field of translational research in sickle cell anemia has expanded greatly and has led to new clinical trials with new therapeutic agents and strategies. In this paper, we review the drugs that are now being investigated in the treatment of sickle cell anemia.