Hemophilia BPhase 1/2NCT05164471
Phase 1/2 Dose Confirmation Study of FLT180a in Hemophilia B
A Phase 1/2 study testing verbrinacogene setparvovec in people with Hemophilia B, run by Spur Therapeutics at 7 sites in 2 countries.
Trial summary
Study of FLT180a gene therapy in adults with Hemophilia B. Up to 9 patients will be enrolled to receive a single dose of FLT180a and be followed for 52 weeks. Results will confirm the dose for a future Phase 3 study. Read more about this study
- Who is it for?
- Ages 18 to 65 years, men only
- Conditions the study is for
- Hemophilia B
- What is being tested?
- verbrinacogene setparvovec
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 6 participants
- Where
- 7 sitesin 2 countries
- Study dates
- 6 Dec 2021to 31 May 2023
- Phase
- Phase 1/2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 to 65 years
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Diagnosis of Hemophilia B with known severe or moderately severe FIX deficiency (≤2% normal circulating FIX activity) for which the subject is on continuous, stable and adequate FIX prophylaxis
- Have acceptable laboratory values of a) Hemoglobin ≥11g/dL; b) Platelets ≥100,000 cells/µL; c) AST, ALT and alkaline phosphatase (ALP) ≤ upper limit of normal (ULN); d) Serum albumin > lower limit of normal (LLN); e) Total bilirubin ≤1.5 x ULN (except if caused by Gilbert's disease); f) Serum creatinine ≤2.0mg/dL.
- Level of neutralizing anti-AAV-S3 antibodies below the limit of the pre-established clinical cutoff using an in vitro transduction inhibition assay within the 4 weeks prior to FLT180a administration
- Has demonstrated ability to accurately, independently and in a timely manner enter bleed diary data during the lead-in study, as judged by the investigator
- At least 150 exposure days to FIX concentrates
- At least 6 months of satisfactory controlled prospective baseline data for bleeding events and FIX consumption data from the FLT-01 lead-in study (ECLIPSE)
Who cannot join
- Any history of alcohol or drug dependence
- Presence of neutralizing anti human FIX antibodies (inhibitor; determined by the Nijmegen modified Bethesda inhibitor assay) at the time of enrolment or a previous history of FIX inhibitor
- Subjects at high risk of thromboembolic events
- Evidence of advanced liver fibrosis
- Prior treatment with a gene transfer medicinal product
- Subjects with active hepatitis B or C
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- Serological evidence of HIV-1, not controlled with anti-viral therapy and as evidenced by cluster of differentiation 4 (CD4)+ counts ≤200 μL
- Cytomegalovirus (CMV) immunoglobulin G positive subjects who are CMV polymerase chain reaction (PCR) positive at screening
- Known coagulation disorder other than hemophilia B
- High sensitivity (hs) troponin-T ≥14 pg/mL during screening
- History of uncontrolled cardiac failure, unstable angina, or myocardial infarction or other acute cardiac conditions requiring clinical management in the past 6 months
- Planned surgical procedure within the next 12 months requiring prophylactic FIX treatment
- Known active severe infection (including documented coronavirus (COVID)-19 infection), or any other significant concurrent, uncontrolled medical condition
Trial locations and contacts
7 sites in 2 countries.
7 sites in 2 countries
United Kingdom4 sites
Glasgow Royal Infirmary
Glasgow
Guys Hospital
London
Royal Free London NHS Foundation Tust
London
Royal Victoria Infirmary
Newcastle
United States3 sites
University of Michigan
Ann Arbor, Michigan, 48109
Children's Hospital of Los Angeles
Los Angeles, California, 90027
University of South Florida
Tampa, Florida, 33612
About this study
Official title: A Dose Confirmation Study of FLT180a (Adeno-associated Viral Vector Containing the Padua Variant of a Codon-optimized Human Factor IX Gene) in Adult Subjects With Hemophilia B
Study of FLT180a gene therapy in adults with Hemophilia B. Up to 9 patients will be enrolled to receive a single dose of FLT180a and be followed for 52 weeks. Results will confirm the dose for a future Phase 3 study.
- Conditions
- Hemophilia B
- Being tested
- verbrinacogene setparvovec
- Medical subject headings
- Hemophilia B
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
verbrinacogene setparvovecGenetic
FLT180a is a gene therapy intended to increase endogenous FIX production in adults with Hemophilia B
| Study group | Role | What they receive |
|---|---|---|
| FLT180a | Experimental | A single dose of FLT180a will be administered. Dose will be determined by enrollment cohort. The first 3 patients will receive 7.7 x 10e11 vg/kg. The dose in subsequent cohorts will be determined by the DMC based on review of data from the prior cohort(s). Receives: Genetic: verbrinacogene setparvovec |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Adverse Events
Measured: Dosing through last study visit (average of 48 weeks)
Secondary outcomes (5)
Number of Participants With FIX Activity Levels >=5% and >= 10%
One-Stage aPTT \& Chromogenic Assay (central lab)
Measured: Last study visit (average of 48 weeks)
Number of Participants With FIX Inhibitor at Any Time Point
Measured: Dosing through last study visit (average of 48 weeks)
Number Patients With Bleeding Episode
Measured: Dosing through last study visit (average of 48 weeks)
Mean Time to Cleared Viral Shedding
Time of first <LLD (lower limit detection) value
Measured: Dosing through last study visit (average of 48 weeks)
Number of Participants With Abnormal Serum Alpha-fetoprotein Levels
Central lab
Measured: Dosing through last study visit (either Week 26 or W52)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Dec 2021
- Study start6 Dec 2021
- Primary completion31 May 2023
- Study completion31 May 2023
Why it stopped: Freeline has decided to pause development of FLT180a for business priorities
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Hemophilia BStudies of the same condition, open and under way.
- 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
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 6 participants (actual)
Sponsor and investigators
- Lead sponsor
- Spur Therapeutics
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05164471
- Sponsor's protocol ID
- FLT180a-06
- Status last verified
- Jul 2026
- First submitted
- 22 Nov 2021
- Last updated
- 31 Jul 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Dose Confirmation Study of FLT180a (Adeno-associated Viral Vector Containing the Padua Variant of a Codon-optimized Human Factor IX Gene) in Adult Subjects With Hemophilia B
- ClinicalTrials.gov ID
- NCT05164471
- Acronym / sponsor ID
- FLT180a-06
- Conditions
- Hemophilia B
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Freeline has decided to pause development of FLT180a for business priorities
- Enrolment
- 6 participants (actual)
- Lead sponsor
- Spur TherapeuticsIndustry (pharma, biotech, devices)
- Study start
- 6 Dec 2021 (actual)
- Primary completion
- 31 May 2023 (actual)
- Study completion
- 31 May 2023 (actual)
- First posted
- 20 Dec 2021 (actual)
- Results
- Posted 31 Jul 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Study of FLT180a gene therapy in adults with Hemophilia B. Up to 9 patients will be enrolled to receive a single dose of FLT180a and be followed for 52 weeks. Results will confirm the dose for a future Phase 3 study.
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| FLT180a | Experimental | Genetic: verbrinacogene setparvovecA single dose of FLT180a will be administered. Dose will be determined by enrollment cohort. The first 3 patients will receive 7.7 x 10e11 vg/kg. The dose in subsequent cohorts will be determined by the DMC based on review of data from the prior cohort(s). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Diagnosis of Hemophilia B with known severe or moderately severe FIX deficiency (≤2% normal circulating FIX activity) for which the subject is on continuous, stable and adequate FIX prophylaxis
- Have acceptable laboratory values of a) Hemoglobin ≥11g/dL; b) Platelets ≥100,000 cells/µL; c) AST, ALT and alkaline phosphatase (ALP) ≤ upper limit of normal (ULN); d) Serum albumin > lower limit of normal (LLN); e) Total bilirubin ≤1.5 x ULN (except if caused by Gilbert's disease); f) Serum creatinine ≤2.0mg/dL.
- Level of neutralizing anti-AAV-S3 antibodies below the limit of the pre-established clinical cutoff using an in vitro transduction inhibition assay within the 4 weeks prior to FLT180a administration
- Has demonstrated ability to accurately, independently and in a timely manner enter bleed diary data during the lead-in study, as judged by the investigator
- At least 150 exposure days to FIX concentrates
Key exclusion criteria (13 listed)
- Any history of alcohol or drug dependence
- Presence of neutralizing anti human FIX antibodies (inhibitor; determined by the Nijmegen modified Bethesda inhibitor assay) at the time of enrolment or a previous history of FIX inhibitor
- Subjects at high risk of thromboembolic events
- Evidence of advanced liver fibrosis
- Prior treatment with a gene transfer medicinal product
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 |
|---|---|---|
| verbrinacogene setparvovecFLT180a is a gene therapy intended to increase endogenous FIX production in adults with Hemophilia B | Genetic | FLT180a |
Primary outcome
Number of Participants With Adverse Events
Time frame: Dosing through last study visit (average of 48 weeks)
5 secondary outcomes
Number of Participants With FIX Activity Levels >=5% and >= 10%
Time frame: Last study visit (average of 48 weeks)
Number of Participants With FIX Inhibitor at Any Time Point
Time frame: Dosing through last study visit (average of 48 weeks)
Number Patients With Bleeding Episode
Time frame: Dosing through last study visit (average of 48 weeks)
Mean Time to Cleared Viral Shedding
Time frame: Dosing through last study visit (average of 48 weeks)
Number of Participants With Abnormal Serum Alpha-fetoprotein Levels
Time frame: Dosing through last study visit (either Week 26 or W52)
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
7 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing verbrinacogene setparvovec in people with Hemophilia B, run by Spur Therapeutics at 7 sites in 2 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 6 inclusion and 13 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: stopped early, as of the sponsor's last update on 31 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 7 sites in United Kingdom, United States. 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. 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?
Yes. Results are posted in the registry (first posted 31 Jul 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Adverse Events (time frame: Dosing through last study visit (average of 48 weeks)). 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 31 Jul 2026.