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

This study is researching an experimental drug called ALN-CFB. The study is focused on people with Paroxysmal Nocturnal Hemoglobinuria (PNH) who are currently taking a complement component C5 inhibitor ("C5-inhibitor") and continue to have anemia (low red blood cell count). The aim of the study is to see how tolerable ALN-CFB is compared to placebo. A placebo looks like the study drug but does not contain any drug. The study is looking at several other research questions, including: * What side effects may happen from taking ALN-CFB * How much ALN-CFB is in the blood at different times * How much Complement Factor B (CFB) protein levels in the blood are affected by ALN-CFB

NCT Number	NCT07187401
Lead Sponsor	Regeneron Pharmaceuticals
Conditions	Paroxysmal Nocturnal Hemoglobinuria (PNH), Persistent Anemia
Enrollment	24 participants
Start Date	2026-02-11
Primary Completion	2029-11-29 (estimated)
Study Completion	2031-07-15 (estimated)
Updated on ClinicalTrials.gov	2026-07-09