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A Study to Investigate the Safety and Effectiveness of a Coagulation Factor IX Gene Insertion Therapy (REGV131-LNP1265) in Pediatric, Adolescent and Adult Participants With Hemophilia B

Phase 1
Recruiting
Conditions
Hemophilia B
Interventions
Registration Number
NCT06379789
Lead Sponsor
Regeneron Pharmaceuticals
Brief Summary

Participants in this study have a genetic mutation, specifically in the coagulation (blood clotting) Factor 9 gene that causes severe or moderately severe hemophilia B. This study is researching an experimental gene insertion therapy (the adding of a gene into your DNA) called REGV131-LNP1265, also called the "study drug". Gene insertion therapy aims to teach the body how to produce clotting factor long-term, without the need for factor replacement therapy.

The main aim of this study is to find a safe and well-tolerated dose of the study drug by checking the side effects that may happen from taking it.

The study is looking at several other research questions including:

* How much study drug is in the blood at different times

* Whether the body makes antibodies against parts of the study drug, which could make the drug less effective or could lead to side effects. Antibodies are proteins produced by the body's immune system in response to a foreign substance

* Whether the body makes antibodies against the clotting factor replacement therapy

* How quality of life is affected by hemophilia B and if it changes after taking study drug

* How joint health is affected by hemophilia B and if it changes after taking study drug

* How often visits are required for the emergency room, urgent care center, physician's office, hospital, telephone or online are required as a result of bleeding events, and if the frequency changes after taking study drug

* How often factor replacement therapy is needed, both on a regular basis for prevention of bleeding, and as needed to treat bleeding events (and it if changes after taking study drug)

* Whether there is a difference in 2 different methods for measuring Factor 9 activity in the blood

Detailed Description

The study will be conducted with a 2-part adaptive design, with enrollment of patients into sequential parts of the study.

Part 1: Dose Escalation and Dose Confirmation in adult patients ≥18 years of age

* Dose Escalation Cohorts to determine the recommended dose for expansion (RDE) of REGV131-LNP1265

* Dose Confirmation Cohort to gain further confidence in safety, tolerability, and Coagulation Factor IX (FIX) functional activity data at the RDE

Part 2: Dose Expansion at the RDE

* Part 2A: Adult patients ≥18 years of age: RDE of REGV131-LNP1265, as determined in Part 1

* Part 2B: Adolescent patients \<18 and ≥12 years of age will be administered weight-adjusted RDE

* Part 2C: Adolescent and Pediatric patients ≥2 to \<12 years may be enrolled in an age staggered sequential manner; first participants aged ≥6 to \<12 years and then participants ≥2 to \<6 years of age and will receive a weight-adjusted RDE

Recruitment & Eligibility

Status
RECRUITING
Sex
Male
Target Recruitment
130
Inclusion Criteria
  1. Confirmed diagnosis of severe or moderately severe hemophilia B with medical history of FIX functional activity (≤2% or <0.02 IU/mL) or documented genotype known to produce severe hemophilia B
  2. Currently taking FIX prophylaxis and previous experience with FIX therapy, as defined in the protocol
  3. Participation in the lead-in period of this interventional study OR a separate lead-in study (R0000-HEMB-2187 [NCT05568459]) for at least 6 months for ABR data while taking FIX prophylaxis, as defined in the protocol

Key

Exclusion Criteria
  1. History of FIX inhibitor (clinical or laboratory-based assessment) on 2 or more occasions
  2. Bethesda inhibitor titer greater than the upper limit of normal (ULN) at screening
  3. Detectable pre-existing antibodies to the adeno-associated virus serotype 8 (AAV8) capsid; as measured by enzyme-linked immunosorbent assay (ELISA) at prescreening (or final lead-in visit, if applicable).
  4. Any significant underlying liver disease such as: cholestatic liver disease, liver cirrhosis, portal hypertension, splenomegaly, hepatic encephalopathy
  5. Evidence of advanced liver fibrosis, as defined in the protocol
  6. Evidence of cirrhosis and/or portal hypertension as assessed by abdominal ultrasound at screening or measured within 6 months prior to the screening visit
  7. History of arterial or venous thrombo-embolic events, as defined in the protocol
  8. History of hypersensitivity to corticosteroids or known medical condition that requires chronic administration of corticosteroids
  9. Previously received any AAV gene-based therapy or intends to receive approved or investigational AAV-based gene therapy other than REGV131-LNP1265 during the study period

NOTE: Other Inclusion/Exclusion Protocol Defined Criteria Apply

Study & Design

Study Type
INTERVENTIONAL
Study Design
SEQUENTIAL
Arm && Interventions
GroupInterventionDescription
Part 2: Dose Expansion ALNP1265Participants ≥18 Years of Age will receive the RDE of REGV131-LNP1265 determined by Part 1
Part 1: Cohort 2 Dose Escalation for RDELNP1265Dose 2 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 1: Cohort 4 Dose Escalation for RDELNP1265Dose 4 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 2: Dose Expansion BLNP1265Participants ≥12 to \<18 Years of Age will receive the administered weight-adjusted RDE of REGV131-LNP1265 determined by Part 1
Part 1: Cohort 1 Dose Escalation for RDELNP1265Starting dose to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 2: Dose Expansion AREGV131Participants ≥18 Years of Age will receive the RDE of REGV131-LNP1265 determined by Part 1
Part 1: Cohort 3 Dose Escalation for RDEREGV131Dose 3 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 1: Cohort 1 Dose Escalation for RDEREGV131Starting dose to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 1: Cohort 2 Dose Escalation for RDEREGV131Dose 2 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 2: Dose Expansion CREGV131Participants ≥2 to \<12 Years of Age will receive the administered weight-adjusted RDE of REGV131-LNP1265 determined by Part 1
Part 1: Cohort 4 Dose Escalation for RDEREGV131Dose 4 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Part 2: Dose Expansion CLNP1265Participants ≥2 to \<12 Years of Age will receive the administered weight-adjusted RDE of REGV131-LNP1265 determined by Part 1
Part 2: Dose Expansion BREGV131Participants ≥12 to \<18 Years of Age will receive the administered weight-adjusted RDE of REGV131-LNP1265 determined by Part 1
Part 1: Cohort 3 Dose Escalation for RDELNP1265Dose 3 of ascending dose level cohorts to determine the RDE of REGV131-LNP1265 and further assess the safety, tolerability, and FIX functional activity data at the RDE
Primary Outcome Measures
NameTimeMethod
Coagulation Factor IX (FIX) functional activity measured using the chromogenic substrate assayAt day 29

Part 1

Change in FIX functional activity in plasma, measured using the chromogenic substrate assayBaseline and at Week 26, after REGV131-LNP1265 dosing at the recommended dose for expansion (RDE)

Part 2A, Part 2B and Part 2C

Severity of TEAEsUp to 104 Weeks

Part 1, Part 2B and Part 2C

Incidence of treatment-emergent adverse events (TEAEs)Up to 104 Weeks

Part 1, Part 2B and Part 2C

Annualized bleeding rate (ABR) following sustained FIX functional activity among participants receiving the RDEOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing

Part 2A, Part 2B and Part 2C

Secondary Outcome Measures
NameTimeMethod
ABR following sustained FIX functional activity among participants receiving the RDEOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing

Part 1

Annualized treated bleeding rate (tABR) following sustained FIX functional activity, among participants receiving the RDEOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing
Detection of total binding antibodies (TAbs) to the adeno-associated virus 8 (AAV8) capsid proteinsUp to 104 Weeks
Detection of neutralizing antibodies/transduction inhibitors (NAb/TI) to the adeno-associated virus 8 (AAV8) capsid proteinsUp to 104 Weeks
Detection of antibodies to CRISPR-associated protein 9 (Cas9) proteinUp to 104 Weeks
Remaining zero spontaneous bleeding events among those receiving the RDE over sustained FIX functional activity periodOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing
Detection of vector DNA in salivaUp to 104 Weeks

Part 1

Detection of vector DNA in semenUp to 104 Weeks

Part 1

Detection of vector DNA in fecesUp to 104 Weeks

Part 1

Severity of TEAEsUp to 104 Weeks

Part 2A

Detection of vector DNA in bloodUp to 104 Weeks

Part 1

Change in FIX functional activity in plasma measured using the chromogenic substrate assayBaseline and at Week 26, after REGV131-LNP1265 dosing at the RDE

Part 1

FIX functional activity in plasma over time during the study period using the chromogenic substrate assayUp to 104 Weeks
Remaining free of FIX replacement therapy among those receiving the RDE following sustained FIX expressionOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing
Detection of antibodies to the F9 transgene product FIX proteinUp to 104 Weeks
Detection of vector DNA in nasal secretionsUp to 104 Weeks

Part 1

Detection of vector DNA in relevant matrices over time based on data analysis from adult cohorts over timeUp to 104 Weeks

Part 2B and Part 2C

Annualized utilization (IU/kg/year) of FIX replacement therapy following sustained FIX functional activity among participants receiving the RDEOver 52 Weeks; Weeks 26 to 78 post-REGV131-LNP1265 dosing
Detection of antibodies to LNP1265Up to 104 Weeks
Detection of vector DNA in urineUp to 104 Weeks

Part 1

Detection of vector DNA in relevant matrices based on data analysis of Part 1 Dose Confirmation CohortUp to 104 Weeks

Part 2A

Concentrations of LNP1265 componentsUp to 29 Days
Concentrations of REGV131 componentsUp to 29 Days
Incidence of TEAEsUp to 104 Weeks

Part 2A

Trial Locations

Locations (9)

Yale HTC

🇺🇸

New Haven, Connecticut, United States

Children's Hospital of Philadelphia (CHOP)

🇺🇸

Philadelphia, Pennsylvania, United States

Addenbrooke's Hospital, Cambridge University Hospitals NHS FT

🇬🇧

Cambridge, United Kingdom

Orthopaedic Hemophilia Treatment Center

🇺🇸

Los Angeles, California, United States

University of California Davis

🇺🇸

Sacramento, California, United States

University California San Francisco

🇺🇸

San Francisco, California, United States

Tulane University School of Medicine, Louisiana Center for Bleeding and Clotting Disorders

🇺🇸

New Orleans, Louisiana, United States

University of Michigan

🇺🇸

Ann Arbor, Michigan, United States

McMaster University Medical Centre - Hamilton Health Sciences

🇨🇦

Hamilton, Ontario, Canada

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