A three-part open-label adaptable phase I/II clinical trial was conducted to evaluate the safety, pharmacokinetics, exploratory efficacy and pharmacodynamics in healthy participants in part 1, in complement blockade-naive patients in part 2 and in patients with PNH receiving treatment with a C5 inhibitor in part 3. The gene discussed is C5; the disease is paroxysmal nocturnal hemoglobinuria.