Study to Assess Safety, Efficacy, Pharmacokinetics, and Pharmacodynamics of Crovalimab in Healthy Volunteers and Participants With Paroxysmal Nocturnal Hemoglobinuria

To join the first part of this study, you need to be a healthy man between 21 and 55 years old. You must be free from certain infections like Hepatitis B, Hepatitis C, and HIV. You also need to have had all your vaccinations for Hepatitis B and against certain types of meningitis. Participants in this part should not smoke, or have quit smoking at least two months before joining.

For the later parts of the study, we are looking for men and women with PNH, aged between 18 and 75 years. It's really important that you are up-to-date with your meningitis vaccinations according to local health guidelines. In some cases, if you're not fully vaccinated or if there's a short time between vaccination and starting the study medicine, you might need to take antibiotics to prevent meningitis.

If you are currently taking other medications for PNH, like immunosuppressants, steroids, or iron supplements, these treatments need to have been at a steady dose for at least four weeks before you can join. Some parts of the study are specifically for people with PNH who haven't been treated with certain types of PNH medications before, or who are looking to change their current treatment.

If you decide to take part in this study, you'll be involved in several steps. Initially, healthy volunteers will receive a single dose of crovalimab, carefully monitored for safety. Later, for people with PNH, you'll receive multiple doses of either crovalimab or a placebo (a dummy treatment). This will involve regular visits to the clinic for medical checks, blood tests, and to receive your study medication.

Throughout the study, doctors and nurses will closely monitor your health, looking for any side effects and how your body reacts to the treatment. There will be various assessments to see if the medication is working and how it's affecting your PNH. The total duration of your participation will depend on which part of the study you are in, but it will involve ongoing follow-up to ensure your well-being.