Paroxysmal Nocturnal Hemoglobinuria (PNH)Phase 1/2NCT07187401
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 Phase 1/2 study testing ALN-CFB in people with Paroxysmal Nocturnal Hemoglobinuria (PNH) and Persistent Anemia, run by Regeneron Pharmaceuticals at 8 sites in 3 countries.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Paroxysmal Nocturnal Hemoglobinuria (PNH), Persistent Anemia
- What is being tested?
- ALN-CFB
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 24 participants
- Where
- 8 sitesin 3 countries
- Study dates
- 11 Feb 2026to 15 Jul 2031
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
8 sites in 3 countries. Contact the study team or a site near you to ask about taking part.
8 sites in 3 countries
South Korea5 sites, 5 recruiting
- Recruiting
The Catholic University of Korea, Seoul St. Mary's Hospital
Seoul, 06591
- Recruiting
Seoul National University Hospital
Seoul, 3080
- Recruiting
Severance Hospital
Seoul, 3722
- Recruiting
Samsung Medical Center
Seoul, 6351
- Recruiting
St. Vincent Hospital - The Catholic University of Korea
Suwon, Gyeonggi-do, 16247
United Kingdom2 sites, 2 recruiting
- Recruiting
St. James's University Hospital
Leeds, West Yorkshire, LS97TF
- Recruiting
Kings College Hospital NHS Foundation Trust
London, SE5 9RS
Canada1 site, 1 recruiting
- Recruiting
Toronto General Hospital
Toronto, Ontario, M5G 2C4
About this study
Official title: 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
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
Read the detailed description
The protocol will be amended to describe Part B of the study after Part A data have been analyzed.
- Being tested
- ALN-CFB, Placebo
- Keywords
- C5 inhibitor, Complement Factor B (CFB) protein, Red Blood Cells
- Medical subject headings
- Hemoglobinuria, Paroxysmal
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ALN-CFBDrug
Administered as defined in the protocol
PlaceboDrug
Administered as defined in the protocol
| Study group | Role | What they receive |
|---|---|---|
| Single-Ascending Dose Escalation | Experimental | Not described Receives: Drug: ALN-CFB |
| Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Occurrence of Treatment-Emergent Adverse Events (TEAEs)
Measured: Through 365 Days
Severity of TEAEs
Measured: Through 365 Days
Secondary outcomes (4)
Concentrations of combined ALN-CFB and major metabolites in plasma
Measured: Through 365 Days
Concentrations of combined ALN-CFB and major metabolites in urine
Measured: Through 24 Hours following ALN-CFB administration
Absolute change from baseline in CFB concentration
Measured: Baseline, Through 365 Days
Percentage change from baseline in CFB concentration
Measured: Baseline, Through 365 Days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Sep 2025
- Study start11 Feb 2026
- Primary completion29 Nov 2029 (estimated)
- Study completion15 Jul 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Paroxysmal Nocturnal Hemoglobinuria (PNH)Studies of the same condition, open and under way.
- More trials run by Regeneron PharmaceuticalsThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Regeneron Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Clinical Trial Management, Study director, Regeneron Pharmaceuticals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07187401
- Sponsor's protocol ID
- ALN-CFB-PNH-2468
- Other IDs
- 2024-519806-11-00
- Status last verified
- Jul 2026
- First submitted
- 18 Sep 2025
- Last updated
- 9 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Study at a glance
From the registry record, last updated by the sponsor on 9 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07187401
- Acronym / sponsor ID
- ALN-CFB-PNH-2468
- Keywords
- C5 inhibitor, Complement Factor B (CFB) protein, Red Blood Cells
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- Regeneron PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 11 Feb 2026 (actual)
- Primary completion
- 29 Nov 2029 (estimated)
- Study completion
- 15 Jul 2031 (estimated)
- First posted
- 23 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Detailed description
The protocol will be amended to describe Part B of the study after Part A data have been analyzed.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Single-Ascending Dose Escalation | Experimental | Drug: ALN-CFB |
| Placebo | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- 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 (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ALN-CFBAdministered as defined in the protocol | Drug | Single-Ascending Dose Escalation |
| PlaceboAdministered as defined in the protocol | Drug | Placebo |
Primary outcome
Occurrence of Treatment-Emergent Adverse Events (TEAEs)
Time frame: Through 365 Days
Severity of TEAEs
Time frame: Through 365 Days
4 secondary outcomes
Concentrations of combined ALN-CFB and major metabolites in plasma
Time frame: Through 365 Days
Concentrations of combined ALN-CFB and major metabolites in urine
Time frame: Through 24 Hours following ALN-CFB administration
Absolute change from baseline in CFB concentration
Time frame: Baseline, Through 365 Days
Percentage change from baseline in CFB concentration
Time frame: Baseline, Through 365 Days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jul 2026.
- Individual participant dataSharing planned: Yes. All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.
Related trials for Paroxysmal Nocturnal Hemoglobinuria (PNH)
Enrolling by invitationObservational study
An Observational Post-Authorization Safety and Effectiveness Study of Ravulizumab in Adult Patients Aged 18 and Older Diagnosed With Paroxysmal Nocturnal Hemoglobinuria Using Multicenter Electronic Medical Records in South Korea
Hemoglobinuria, Paroxysmal
RecruitingPhase 2
Allogeneic Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia and Other Bone Marrow Failure Syndromes Using G-CSF Mobilized CD34+ Selected Hematopoietic Precursor Cells Co-Infused With a Reduced Dose of Non-Mobilized Donor T-cells
Severe Aplastic Anemia, MDS (Myelodysplastic Syndrome)
RecruitingPhase 3
A Study in Adult Patients With Paroxysmal Nocturnal Hemoglobinuria (PNH) to Evaluate How Safe Long-term Treatment With Pozelimab + Cemdisiran Combination Therapy is and How Well it Works
Paroxysmal Nocturnal Hemoglobinuria
Not yet recruitingPhase 3
A Study of Efficacy and Safety of FXS6837 in Anti-C5 Treated PNH Patients.
Paroxysmal Nocturnal Hemoglobinuria
RecruitingPhase 2
Haplo-identical Transplantation for Severe Aplastic Anemia, Hypo-plastic MDS and PNH Using Peripheral Blood Stem Cells and Post-transplant Cyclophosphamide for GVHD Prophylaxis
Severe Aplastic Anemia (SAA), Hypo-Plastic Myelodysplastic Syndrome (MDS)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Clinical Trial Management study director
Regeneron Pharmaceuticals
8 sites in 3 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing ALN-CFB in people with Paroxysmal Nocturnal Hemoglobinuria (PNH) and Persistent Anemia, run by Regeneron Pharmaceuticals at 8 sites in 3 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 9 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 8 sites in South Korea, United Kingdom, Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Clinical Trials Administrator (844-734-6643, clinicaltrials@regeneron.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Occurrence of Treatment-Emergent Adverse Events (TEAEs) (time frame: Through 365 Days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jul 2026.