A Study Evaluating the Efficacy and Safety of Crovalimab Versus Eculizumab in Participants With Paroxysmal Nocturnal Hemoglobinuria (PNH) Not Previously Treated With Complement Inhibitors

To join this study, you generally need to be at least two years old and weigh 40 kilograms (about 6 stone 4 pounds) or more. For children weighing less than 40 kg, there are specific guidelines. You must have a confirmed diagnosis of PNH, which means it's been properly checked by doctors. Also, a specific blood test for PNH, called LDH, needs to be at least twice the normal level, showing that your PNH is active. It's also important to have had your meningococcal vaccinations or be willing to have them soon after starting the study medicine.

There are also some reasons why you might not be able to join. For example, if you've already had treatment with a complement inhibitor (the type of medicine being studied), you wouldn't be eligible. You also can't have had a bone marrow transplant or a meningococcal infection recently. If you have a specific type of blood disorder called myelodysplastic syndrome with a high risk, or if you are pregnant, breastfeeding, or planning to become pregnant during or shortly after the study, you also wouldn't be able to take part. It's also important that you're not currently in another study using an experimental medicine.

If you join this study, you'll be given either crovalimab or eculizumab. Both are medicines for PNH. You will have regular visits with the study team for blood tests, health checks, and to discuss any side effects. You'll need to follow specific instructions regarding contraception if you are a woman who could become pregnant, and this will continue for some time after your last dose of the study medicine (about 10.5 months for crovalimab or 3 months for eculizumab). The total length of your participation, including follow-up, will be explained by the study doctor, but generally, studies like this involve regular visits over a period of time.