A First-in-Human Safety and Efficacy Study of ALN-CFB, a Small Interfering RNA (siRNA) Targeting Complement Factor B, in Adult Participants With Paroxysmal Nocturnal Hemoglobinuria With Persistent Anemia on a C5 Inhibitor

To join this study, you must be an adult aged 18 or over. You need to have been diagnosed with PNH, confirmed by specific blood tests. It's also important that you've been consistently taking your current PNH medication (a C5 inhibitor like eculizumab, ravulizumab, or crovalimab) for at least 24 weeks before the study starts.

Your blood tests will need to show that you still have anaemia, meaning your haemoglobin level is 10.5 g/dL or lower, and you have a certain level of developing red blood cells (reticulocytes).

You wouldn't be able to join this study if you've had a bone marrow or organ transplant, or if you've had certain serious infections, such as meningococcal infection. Active infections or recent serious infections needing treatment would also prevent you from joining. Additionally, if you have other severe medical conditions not related to your PNH, or if tests show your bone marrow isn't working properly, you might not be suitable.

If you join this study, you'll either receive the experimental drug, ALN-CFB, or a placebo. Neither you nor your doctor will know which one you're receiving. You'll have regular visits to the study clinic for check-ups, which will include blood tests, physical exams, and answering questions about how you’re feeling. These visits are important for doctors to monitor your health, check for side effects, and see how the study drug is working. The total time you'd be involved in the study isn't specified here, but clinical studies usually involve a series of visits over several months.