This is an open-label study to evaluate pegcetacoplan in people with PNH who are 12-17 years old. The study will consist of a 4-week screening period followed by a 16-week treatment period. Participants switching from a C5 inhibitor will have an additional 4 week run-in period between the screening and treatment periods. At the completion of the study treatment period, participants will either enter a long-term extension period or a 2-month follow-up period.~All eligible study participants will receive pegcetacoplan, administered via subcutaneous infusion twice a week at home. The subcutaneous infusion requires two small needles to be inserted into the fatty layer of tissue under the skin and the investigational medication will flow into the body. Study participants and/or caregivers will be trained on home administration of pegcetacoplan.
The purpose of this study is to evaluate the safety, effectiveness, and biological activity (how the investigational medication is processed by the body) of pegcetacoplan in 12-17 year-olds (adolescents) who have paroxysmal nocturnal hemoglobinuria (PNH).