Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the body's innate immune system. This destructive process occurs due to deficiency of the red blood cell surface protein DAF, which normally inhibits such immune reactions. Since the complement cascade attacks the red blood cells within the blood vessels of the circulatory system, the red blood cell destruction (hemolysis) is considered an intravascular hemolytic anemia. There is ongoing research into other key features of the disease, such as the high incidence of venous blood clot formation. Research suggests that PNH thrombosis is caused by both the absence of GPI-anchored complement regulatory proteins on PNH platelets and the excessive consumption of nitric oxide (NO).
Paroxysmal cold hemoglobinuria (PCH) or Donath–Landsteiner hemolytic anemia (DLHA) is an autoimmune hemolytic anemia featured by complement-mediated intravascular hemolysis after cold exposure. It can present as an acute non-recurrent postinfectious event in children, or chronic relapsing episodes in adults with hematological malignancies or tertiary syphilis. Described by Julius Donath (1870–1950) and Karl Landsteiner (1868–1943) in 1904, PCH is one of the first clinical entities recognized as an autoimmune disorder.
Eculizumab, sold under the brand name Soliris among others, is a recombinant humanized monoclonal antibody used to treat paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), generalized myasthenia gravis, and neuromyelitis optica. In people with PNH, it reduces both the destruction of red blood cells and need for blood transfusion, but does not appear to affect the risk of death. Eculizumab was the first drug approved for each of its uses, and its approval was granted based on small trials. It is given by intravenous infusion.
The Ham test is a blood test used in the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). Patient red blood cells (RBCs) are placed in mild acid; a positive result indicates PNH or congenital dyserythropoietic anemia. This is now an obsolete test for diagnosing PNH due to its low sensitivity and specificity.
Enfortumab vedotin, sold under the brand name Padcev, is an antibody-drug conjugate used for the treatment of urothelial cancer. It is a nectin-4-directed antibody and microtubule inhibitor conjugate. Enfortumab refers to the monoclonal antibody part, and vedotin refers to the payload drug (MMAE) and the linker.
Acalabrutinib, sold under the brand name Calquence, is a medication used to treat various types of non-Hodgkin lymphoma, including mantle cell lymphoma (MCL) and chronic lymphocytic leukemia/small lymphocytic Lymphoma (CLL/SLL). It may be used both in relapsed as well as in treatment-naive settings.
Tucatinib, sold under the brand name Tukysa, is an anticancer medication used for the treatment of HER2-positive breast cancer. It is a small molecule inhibitor of HER2. It was developed by Array BioPharma and licensed to Cascadian Therapeutics.
CD55deficiency, also called DAF deficiency or CHAPLE syndrome, is a rare genetic disorder of the immune system. CHAPLE stands for "CD55 deficiency with hyper-activation of complement, angiopathic thrombosis, and severe protein-losing enteropathy (PLE)." The disorder usually manifests in childhood and can be life-threatening. This condition was described by Özen, et al. in 2017.
Ravulizumab, sold under the brand name Ultomiris, is a humanized monoclonal antibody complement inhibitor medication designed for the treatment of paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome. It is designed to bind to and prevent the activation of Complement component 5 (C5).
Sutimlimab, sold under the brand name Enjaymo, is a monoclonal antibody that is used to treat adults with cold agglutinin disease (CAD). It is given by intravenous infusion. Sutimlimab prevents complement-enhanced activation of autoimmune human B cells in vitro.
Pegcetacoplan, sold under the brand name Empaveli, among others, is a medication used to treat paroxysmal nocturnal hemoglobinuria and geographic atrophy of the retina. Pegcetacoplan is a complement inhibitor.
Zilucoplan, sold under the brand name Zilbrysq, is a medication used for the treatment of generalized myasthenia gravis. It is a complement inhibitor that is injected subcutaneously.
Maralixibat chloride, sold under the brand name Livmarli, is a medication used to treat cholestatic pruritus in people with Alagille syndrome. Maralixibat chloride is an ileal bile acid transporter (IBAT) inhibitor.
Avacopan, sold under the brand name Tavneos, is a medication used to treat anti-neutrophil cytoplasmic autoantibody-associated vasculitis. Avacopan is a complement 5a receptor antagonist and a cytochrome P450 3A4 inhibitor.
Mitapivat, sold under the brand name Pyrukynd, is a medication used to treat hemolytic anemia. It is taken as the sulfate hydrate salt by mouth. Mitapivat is a pyruvate kinase activator.
Teclistamab, sold under the brand name Tecvayli, is a human bispecific monoclonal antibody used for the treatment of relapsed and refractory multiple myeloma. It is a bispecific antibody that targets the CD3 receptor expressed on the surface of T-cells and B-cell maturation antigen (BCMA), which is expressed on the surface of malignant multiple myeloma B-lineage cells.
Iptacopan, sold under the brand name Fabhalta, is a medication used for the treatment of paroxysmal nocturnal hemoglobinuria. It is a complement factor B inhibitor that was developed by Novartis. It is taken by mouth.
The sucrose lysis test is a diagnostic laboratory test used for diagnosing paroxysmal nocturnal hemoglobinuria (PNH), as well as for hypoplastic anemias and any hemolytic anemia with an unclear cause. The test works by using sucrose, which creates a low ionic strength environment that allows complement to bind to red blood cells. In individuals with PNH, some red blood cells are especially vulnerable to lysis caused by complement. The test may also produce suspicious results in other hematologic conditions, including megaloblastic anemia and autoimmune hemolytic anemia. False-negative results can occur when complement activity is absent in the serum. A simpler alternative called the sugar water test also involves mixing blood with sugar and observing for hemolysis, using the same principle as the sucrose lysis test.
Epcoritamab, sold under the brand name Epkinly, is a monoclonal antibody anticancer medication used for the treatment of diffuse large B-cell lymphoma. Epcoritamab is a bispecific CD20-directed CD3 T-cell engager. Epcoritamab was co-developed by AbbVie and Genmab.
Crovalimab is an C5 inhibiting monoclonal antibody under investigation by Roche/Genentech for the treatment of paroxysmal nocturnal hemoglobinuria (PNH).
