ClinicalTrials.gov record NCT07187401
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
A Randomized, Double-Blind, Placebo-Controlled, First-In-Human Study of the Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of ALN-CFB, an Investigational siRNA Therapeutic Against Complement Factor B, in Participants With Paroxysmal Nocturnal Hemoglobinuria and Persistent Anemia on Approved C5-Inhibitor Therapy
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴
AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
This first-in-human study enrolls adults with PNH who remain anemic while taking an approved C5 inhibitor. It is a randomized, double-blind, placebo-controlled trial testing the investigational drug ALN-CFB. The study compares tolerability, safety, pharmacokinetics, and effects on Complement Factor B levels.
What it is studying. The study is testing the safety and tolerability of ALN-CFB versus placebo. It will measure how much ALN-CFB and its metabolites appear in blood and urine, and whether ALN-CFB changes blood levels of Complement Factor B. Adverse events and laboratory measures will be collected through the study period (outcomes are tracked through about 365 days).
What the researchers hope to learn. To assess ALN-CFB's safety and tolerability; to characterize its pharmacokinetics and metabolites; and to measure changes in Complement Factor B concentration.
What this study is about
The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.
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
Interventions being studied
Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.
- Drug
- ALN-CFB
- Placebo
Eligibility
The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.
Inclusion criteria
- Has been diagnosed with PNH confirmed by a history of high flow cytometry from prior testing
- Treated with a stable dose of C5 inhibitor (eculizumab or approved eculizumab biosimilar, ravulizumab, or crovalimab) for at least 24 weeks prior to screening visit, as described in the protocol
- Has hemoglobin ≤10.5 g/dL at screening visit 1, with evidence of anemia prior to this visit, as described in the protocol
- Has peripheral blood reticulocyte count of ≥100 x 10\^9/L at screening visit 1
- Key
Exclusion criteria
- Has history of bone marrow transplantation or receipt of an organ transplant
- Has history of meningococcal infection or similar recurrent infections by other encapsulated bacterial organisms
- Has any active, ongoing infection or a recent infection requiring ongoing systemic treatment with antibiotics, antivirals, or antifungals within 2 weeks of screening or during the screening period
- Has laboratory evidence of bone marrow failure, as described in the protocol
- Have recent, unstable medical conditions, not related to PNH or PNH-related complications, as described in the protocol
- NOTE: Other Protocol Defined Inclusion / Exclusion Criteria Apply
Study description and what participation involves
The study's detailed description, as published on ClinicalTrials.gov.
Detailed description from the registry
The protocol will be amended to describe Part B of the study after Part A data have been analyzed.
AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴
AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
Participants are randomized and receive either the investigational drug ALN-CFB or a matching placebo, given per the study protocol in a single-ascending dose design with blinding. They will have repeated blood and urine samples to measure drug levels and Complement Factor B and will be monitored for side effects. Urine collections may include samples within 24 hours after dosing, and overall safety and laboratory monitoring continue through about 365 days. Participation involves multiple clinic visits, safety assessments, and reporting any adverse symptoms to the study team.
How the study is structured. Interventional, randomized, quadruple‑masked trial with a single-ascending dose escalation design. Participants are assigned to receive ALN-CFB or matching placebo. Study procedures include drug dosing, blood and urine sampling for drug levels and CFB measurement, safety monitoring, and follow-up visits over the outcome period (measures reported through about 365 days).
Questions you could ask
These questions are suggestions for a conversation with the study team or your own clinician, not advice.
- Some participants receive a placebo. How is that decided, and what happens for placebo-group participants when the study ends?
- This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
- The listed sites are in Canada, South Korea, United Kingdom. Is any of them reachable for me, and does the study help with travel?
- Which of the eligibility criteria would need to be checked with tests before I could join?
More on paroxysmal nocturnal hemoglobinuria
Important dates
- Study start
- Feb 11, 2026
- Primary completion
- Nov 29, 2029 (estimated)
- Study completion
- Jul 15, 2031 (estimated)
- Target enrollment
- 24 participants (estimated)
- Last updated on registry
- Jul 9, 2026
- Data verified
- Oct 10, 2026
Sponsor and research team
The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.
- Lead sponsor
- Regeneron Pharmaceuticals
Central study contact
If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.
- Clinical Trials Administrator 📞 844-734-6643 ✉ clinicaltrials@regeneron.com
Participating sites (8)
- Toronto General HospitalRecruiting
Toronto, Ontario, M5G 2C4 · Canada
- St. Vincent Hospital - The Catholic University of KoreaRecruiting
Suwon, Gyeonggi-do, 16247 · South Korea
- The Catholic University of Korea, Seoul St. Mary's HospitalRecruiting
Seoul, 06591 · South Korea
- Seoul National University HospitalRecruiting
Seoul, 3080 · South Korea
- Severance HospitalRecruiting
Seoul, 3722 · South Korea
- Samsung Medical CenterRecruiting
Seoul, 6351 · South Korea
- St. James's University HospitalRecruiting
Leeds, West Yorkshire, LS97TF · United Kingdom
- Kings College Hospital NHS Foundation TrustRecruiting
London, SE5 9RS · United Kingdom
Terms used on this page · explanations by MedicalUpdates.ai
- placebo
- A treatment that looks like the study treatment but contains no active ingredient. Some participants receive it instead of the study treatment, usually without knowing which they got.
- study drug
- A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
- stable dose
- A dose that has not changed for a defined period before the study starts. Studies may require this so that background treatment is relatively stable when study measurements begin.
- prior to screening
- The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
- Exclusion Criteria
- The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
- Key Inclusion Criteria
- The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.
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