To Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of KP104

The purpose of this study is to evaluate the safety, tolerability, immunogenicity, pharmacokinetics, pharmacodynamics, and efficacy of KP104 in complement inhibitor-naïve participants with PNH. The study will be conducted in 2 parts. Part 1 is a dose-selection study to assess escalating doses and varying dose intervals of KP104. Part 2 is a proof-of-concept (POC) study assessing the efficacy of the optimal intravenous (IV) loading dose followed by the optimal maintenance dose and regimen of KP104. Participants who complete the Initial Treatment Period and demonstrate benefit from KP104 will be eligible for a 9-month open-label extension (OLE) treatment period.