Abstract: A method for screening for a therapeutic drug for a disease involving excessive activation of a complement, using a s cytotoxicity marker associated with the complement as an index, including (1a) a step of adding a complement to a cell produced from a stem cell to cause the cell to form a cytotoxicity marker associated with the complement, and (2a) a step of adding a therapeutic drug candidate, and selecting a substance that decreases the amount of the cytotoxicity marker is provided by the present invention.

Abstract: The present invention provides a composition suitable as a composition for treating blood coagulation and/or complement disorders (raw materials for producing therapeutic agents for these diseases) and a method for effectively producing the composition. A method for producing a composition for treating blood coagulation and/or complement disorders according to the present invention includes the following steps of: (1) embedding an organoid formed from vascular endothelial cells or vascular endothelial cells and hepatocytes, in an extracellular matrix; (2) culturing the extracellular matrix; and (3) collecting a culture supernatant from the culture obtained in the step (2).