Phase 1/2 Dose Confirmation Study of FLT180a in Hemophilia B

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.

Study Overview

• Status: Terminated
• Conditions: Hemophilia B
• Intervention / Treatment: Genetic: verbrinacogene setparvovec

• Study Type: Interventional
• Enrollment (Actual): 6
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United Kingdom
  • Glasgow, United Kingdom
    • Glasgow Royal Infirmary
  • London, United Kingdom
    • Guys Hospital
  • London, United Kingdom
    • Royal Free London NHS Foundation Tust
  • Newcastle, United Kingdom
    • Royal Victoria Infirmary
• United States
  • California
    • Los Angeles, California, United States, 90027
      • Children's Hospital of Los Angeles
  • Florida
    • Tampa, Florida, United States, 33612
      • University of South Florida
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

• 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)

Key Exclusion Criteria:

• 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
• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: FLT180a; 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).	Genetic: verbrinacogene setparvovec; FLT180a is a gene therapy intended to increase endogenous FIX production in adults with Hemophilia B

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Number of Participants With Adverse Events	Dosing through last study visit (average of 48 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With FIX Activity Levels >=5% and >= 10%	One-Stage aPTT & Chromogenic Assay (central lab)	Last study visit (average of 48 weeks)
Number of Participants With FIX Inhibitor at Any Time Point		Dosing through last study visit (average of 48 weeks)
Number Patients With Bleeding Episode		Dosing through last study visit (average of 48 weeks)
Mean Time to Cleared Viral Shedding	Time of first <LLD (lower limit detection) value	Dosing through last study visit (average of 48 weeks)
Number of Participants With Abnormal Serum Alpha-fetoprotein Levels	Central lab	Dosing through last study visit (either Week 26 or W52)

Collaborators and Investigators

• Sponsor: Spur Therapeutics

Study record dates

Study Major Dates

• Study Start (Actual): December 6, 2021
• Primary Completion (Actual): May 31, 2023
• Study Completion (Actual): May 31, 2023

Study Registration Dates

• First Submitted: November 22, 2021
• First Submitted That Met QC Criteria: December 7, 2021
• First Posted (Actual): December 20, 2021

Study Record Updates

• Last Update Posted (Actual): July 31, 2026
• Last Update Submitted That Met QC Criteria: July 6, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Hematologic Diseases; Blood Coagulation Disorders; Hemorrhagic Disorders; Genetic Diseases, X-Linked; Blood Coagulation Disorders, Inherited; Coagulation Protein Disorders; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Hemic and Lymphatic Diseases; Hemophilia B
• Other Study ID Numbers: FLT180a-06

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No