Clinical Research Directory

Inclusion Criteria: * Body weight \>=40 kg. * Male or female with confirmed diagnosis of HbSS (SCD genotype of sickle cell anemia) or HbSβ0 (SCD genotype of sickle cell beta zero thalassemia). * Two or more (\>=2) to \<=10 documented VOEs in the 12 months prior to randomisation. * If receiving concurrent SCD-directed therapy, the participant must have been on a stable dose for a minimum of 3 months prior to study enrollment. There should be no plans to modify the participants' dosing throughout the study duration, other than for safety reasons. * If receiving erythropoietin, the participant must have been prescribed this medication for the preceding 3 months and be dose-stabilised for at least 3 months prior to study enrollment. * Vaccination against N. meningitides serotypes A, C, W, and Y and Vaccinations against H. influenza type B and S. pneumonia. * Participants who have been vaccinated (partially or in full) against SARS-CoV-2 with a locally approved vaccine are eligible to be enrolled in the study, 3 days or longer after inoculation. * Adequate hepatic and renal function. * For women of childbearing potential: agreement to remain abstinent or use contraception during the treatment period and for 10.5 months after the final dose of study treatment. Exclusion Criteria: * History of hematopoietic stem cell transplant. * Participating in a chronic transfusion program and/or planning on undergoing an exchange transfusion during the duration of the study. * History of hypersensitivity, allergic, or anaphylactic reactions to any ingredient contained in the study treatment. * Received active treatment on another investigational trial within 28 days (or within five half-lives of that agent, whichever is greater) prior to screening visit, or plans to participate in another investigational drug trial. * Hemoglobin \<6 g/dL. * Known or suspected hereditary complement deficiency. * Active systemic bacterial, viral, or fungal infection within 14 days before first drug administration. * Presence of fever (\>=38 degrees Celsius) within 7 days before the first drug administration. * Immunised with a live attenuated vaccine within 1 month before first drug administration. * Pregnant or breastfeeding, or intending to become pregnant during the study or within 10.5 months after the final dose of study treatment. * Known HIV infection with documented CD4 count \<200 cells/microliter within 24 weeks prior to screening. * History of N. meningitidis infection within the prior 6 months.