The U.S. Food and Drug Administration (FDA) has approved Bkemv (eculizumab-aeeb), an interchangeable biosimilar to Soliris (eculizumab). The treatment is approved for both paroxysmal nocturnal hemoglobinuria (PNH), to reduce hemolysis, and atypical hemolytic uremic syndrome (aHUS), to inhibit complement-mediated thrombotic microangiopathy.
PNH and aHUS
PNH is an acquired rare disorder that leads to the premature death and impaired production of blood cells. It can occur at any age, but is usually diagnosed in young adulthood. People with PNH have recurring episodes of symptoms due to hemolysis, which may be triggered by stresses on the body such as infections or physical exertion. This results in a deficiency of various types of blood cells and can cause signs and symptoms such as fatigue, weakness, abnormally pale skin (pallor), shortness of breath, and an increased heart rate. People with PNH may also be prone to infections and abnormal blood clotting or hemorrhage, and are at increased risk of developing leukemia. It is caused by acquired, rather than inherited, genetic changes in the PIGA gene; the condition is not passed down to children of affected individuals.
There are numerous orphan drugs approved to manage patients with PNH, of which eculizumab was the first medication approved back in 2007.
aHUS is a rare disease that causes abnormal blood clots to form in small blood vessels in the kidneys. These clots can cause serious medical problems if they restrict or block blood flow, including hemolytic anemia, thrombocytopenia, and kidney failure. It can occur at any age and is often caused by a combination of environmental and genetic factors. Genetic factors involve genes that code for proteins that help control the complement system. Environmental factors include certain medications (such as anticancer drugs), chronic diseases (e.g., systemic sclerosis and malignant hypertension), viral or bacterial infections, cancers, organ transplantation, and pregnancy. In about 60% of aHUS, a genetic change may be identified. The genes associated with genetic aHUS include C3, CD46 (MCP), CFB, CFH, CFHR1, CFHR3, CFHR4, CFI, DGKE, and THBD. Genetic changes in these genes increase the likelihood of developing aHUS, rather than directly causing the disease. In most cases, there is no family history of the disease.
Eculizumab
Interchangeable biosimilars are treatments that are approved as an alternative to a prescribed treatment and do not require the intervention of a healthcare provider.
Eculizumab is a monoclonal antibody that binds to the complement C5 protein, inhibiting activation of the complement system. This prevents the breakdown of red blood cells.
Eculizumab comes with boxed warning for an increased risk of serious and life-threatening meningitis infections. The biosimilar is only available via a Risk Evaluation and Mitigation Strategy (REMS).
To learn more, visit https://www.fda.gov/news-events/press-announcements/fda-approves-first-interchangeable-biosimilar-two-rare-diseases
For more information on rare blood diseases, visit https://checkrare.com/diseases/hematologic-disorders/
