Samsung Bioepis has begun recruiting patients with paroxysmal nocturnal hemoglobinuria (PNH) in India for a phase 3 clinical study of its proposed eculizumab biosimilar, SB12, referencing Soliris. The double-blind, multicenter, crossover?study?will compare the efficacy, safety, pharmacokinetics (PK), and immunogenicity of SB12 with the reference eculizumab in approximately 50 patients with PNH, a rare, life-threatening?disease of the blood characterized by destruction of red blood cells, presence of blood clots, and impaired bone marrow function. Patients will be randomized to receive 600 mg of either the biosimilar or the reference eculizumab through intravenous administration every week for 4 weeks. Then, they will receive 900 mg of eculizumab for the fifth week, and 900 mg every 2 weeks until week 52. At week 26, patients initially randomized to the biosimilar will be switched to the reference, and those who initiated treatment with the reference will be switched to the biosimilar. The primary outcome measures are hemolysis as measured by lactate dehydrogenase at week 26 in a parallel comparison and at week 52 by a crossover comparison. The study?s estimated completion date is July 2021. In addition to PNH, the reference eculizumab is also approved by the FDA to treat atypical hemolytic uremic syndrome (a rare?disease?that causes abnormal blood clots to form in the small blood vessels in the kidneys), generalized myasthenia gravis (a rare, autoimmune, neuromuscular junction?disorder), and,?most recently, neuromyelitis optica?spectrum disorder (NMOSD, a rare disorder of the central nervous system). The European Medicines Agency?s Committee for Medicinal Products for Human Use has also?adopteda positive opinion of eculizumab in for the treatment of NMOSD, and the European Commission will make a final determination on authorizing the drug for this fourth indication. At least one other biosimilar developer is targeting the high-cost Soliris: Amgen?s proposed biosimilar, ABP 959, was recently shown in a phase 1 study to have similar PK and pharmacodynamics to the reference drug in patients 219 healthy volunteers. The proposed biosimilar also demonstrated similar safety and immunogenicity to Soliris.