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Study to Determine the Safety and Efficacy of rFIXFc in Previously Untreated Males With Severe Hemophilia B

An Open-Label, Multicenter Evaluation of the Safety and Efficacy of Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc; BIIB029) in the Prevention and Treatment of Bleeding in Previously Untreated Patients With Severe Hemophilia B

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT02234310
Acronym
PUPs B-LONG
Enrollment
33
Registered
2014-09-09
Start date
2014-11-13
Completion date
2019-08-20
Last updated
2022-03-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hemophilia B

Keywords

prophylaxis treatment, episodic treatment

Brief summary

The primary objective of the study was to evaluate the safety of recombinant coagulation factor IX Fc fusion protein (rFIXFc, BIIB029) in previously untreated patients (PUPs) with severe hemophilia B. Secondary objectives were to evaluate the efficacy of rFIXFc in the prevention and treatment of bleeding episodes in PUPs, and to evaluate rFIXFc consumption for prevention and treatment of bleeding episodes in PUPs.

Interventions

BIOLOGICALrFIXFc

Adjustments to the dose and interval of rFIXFc was made in this study based on investigator discretion using available pharmacokinetic (PK) data, subsequent FIX trough and peak levels, level of physical activity, and bleeding pattern, in accordance with local standards of care for a prophylactic regimen. There was an option to start study dosing as episodic treatment (on-demand).

Sponsors

Swedish Orphan Biovitrum
CollaboratorINDUSTRY
Bioverativ, a Sanofi company
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
MALE
Age
No minimum to 17 Years
Healthy volunteers
No

Inclusion criteria

Key Inclusion Criteria: * Weight \>=3.5 kilogram at the time of informed consent. * Severe hemophilia B was defined as less than or equal to (\<=)2 International Units per deciliter (IU/dL) (\<=2 percent \[%\]) endogenous FIX documented in the medical record or as tested during the Screening Period. Key

Exclusion criteria

* History of positive inhibitor testing. A prior history of inhibitors was defined based on a participant's historical positive inhibitor test using the local laboratory Bethesda value for a positive inhibitor test (that is equal to or above lower limit of detection). * History of hypersensitivity reactions associated with any rFIXFc administration. * Exposure to blood components or injection with a coagulation factor IX (FIX) concentrate (including plasma derived) other than rFIXFc. * Injection with commercially available rFIXFc more than 28 days prior to Screening. * More than 3 injections of commercially available rFIXFc prior to confirmation of eligibility. * Other coagulation disorders in addition to hemophilia B. * Any concurrent clinically significant major disease that, in the opinion of the Investigator, would have made the participant unsuitable for enrollment (example HIV infection with cluster of differentiation 4 (CD4) lymphocyte count less than (\<)200 cells/microliter (mcL) or a viral load greater than (\>)200 particles/mcL, or any other known congenital or acquired immunodeficiency). * Current systemic treatment with chemotherapy and/or other immunosuppressant drugs. Use of steroids for treatment of asthma or management of acute allergic episodes or otherwise life-threatening episodes was allowed. Treatment in these circumstances should not have exceeded a 14-day duration. * Participation within the past 30 days in any other clinical study involving investigational treatment. * Current enrollment in any other clinical study involving investigational treatment. * Inability to comply with study requirements. * Other unspecified reasons that, in the opinion of the Investigator or Bioverativ, would have made the participant unsuitable for enrollment. NOTE: Other protocol-defined inclusion/

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Participants With Confirmed Inhibitor Development as Measured by the Nijmegen-Modified Bethesda AssayUp to 3 yearsDevelopment of an inhibitor was defined as an inhibitor test result of \>= 0.60 Bethesda units per milliliter (BU/mL) that was confirmed by a second test result of \>=0.60 BU/mL from a separate sample, drawn 2 to 4 weeks after the date when the original sample was drawn, with both tests performed by the central laboratory using Nijmegen-modified Bethesda assay.

Secondary

MeasureTime frameDescription
Annualized Number of Spontaneous Joint Bleeding EpisodesUp to 3 yearsBleeding episodes were classified as spontaneous if parent/caregiver/participant records a bleeding event when there is no known contributing factor such as a definite trauma or antecedent strenuous activity. Annualized spontaneous joint bleeding episodes=(Total number of spontaneous joint bleeding episodes during efficacy period (EP) divided by total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc per treatment regimen excluding major and minor surgical/rehabilitation periods and large injection intervals (\>28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.
Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleUp to 3 yearsUsing e-diary, each participant's parent/caregiver rated treatment response to any bleeding episode (BE) at approximately 8 to 12 hours from time of injection and prior to additional doses of rFIXFc given for same BE using 4-point scale:- 1=Excellent: abrupt pain relief and/or improvement in signs of bleeding within approximately 8 hours after initial injection; 2=Good: definite pain relief and/or improvement in signs of bleeding within approx. 8 hours after injection, but possibly requiring more than 1 injection after 24-48 hours for complete resolution; 3=Moderate: Probable/slight beneficial effect within 8 hours after initial injection and requires more than 1 injection and 4=None: No improvement or condition worsens within approx. 8 hours after initial injection. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.
Total Number of Exposure Days (EDs)Up to 3 yearsAn ED was defined as a 24-hour period in which a participant received one or more doses of rFIXFc injections, with the time of the first injection of rFIXFc defined as the start of the ED. Participant who did not have a particular injection type were counted as having zero injections for that type.
Annualized Number of Bleeding Episodes (Spontaneous and Traumatic) Per Participant (Annualized Bleeding Rate [ABR])Up to 3 yearsABR was annualized number of bleeding episodes during efficacy period (EP) per participant normalized to a 1-year interval of time. Bleeding episodes were classified as: spontaneous if parent/caregiver/participant records bleeding event when there is no known contributing factor such as definite trauma or antecedent strenuous activity; and traumatic when there is known reason for bleed. ABR=(Number of bleeding episodes during EP/total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc per treatment regimens excluding surgical/rehabilitation periods and large injection intervals (greater than \[\>\]28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.
Number of Injections of rFIXFc Required to Resolve a Bleeding EpisodeUp to 3 yearsNumber of injections of rFIXFc required to resolve a bleeding episode during efficacy period (EP) were reported. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc according to the treatment regimens of the study excluding surgical/rehabilitation periods and large injection intervals (\>28 days). All injections given from the initial sign of a bleed, until the last date/time within the bleed window were counted. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.
Average Dose Per Injection of rFIXFc Required to Resolve a Bleeding EpisodeUp to 3 yearsThe average dose of rFIXFc per injection per bleeding episode was calculated as the average of all doses (IU/kg) administered to treat the bleeding episode during efficacy period (EP). EP begins with the first treatment regimen dose of rFIXFc and ends with the last dose (regardless of the reason for dosing). Surgery/rehabilitation periods are not included in the EP. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.
Change From Baseline in rFIXFc Incremental Recovery (IR)Baseline, Weeks 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, and 144Blood samples were taken at trough and Cmax (maximum concentration) for assessment of incremental recovery, measured by the one-stage clotting assay. IR (International Units per deciliter \[IU/dL\] per IU/kg) = (Cmax for FIX activity - Pre-dose FIX activity) (IU/dL)/ Actual dose (IU/kg), where Cmax is 30 minute FIX activity post-dose and FIX activity less than (\<)0.5 IU/dL was set to 0 IU/dL for calculation of IR.
Total Annualized rFIXFc Consumption Per Participant for the Prevention and Treatment of Bleeding EpisodesUp to 3 yearsTotal annualized rFIXFc consumption (in IU/kg) was calculated for each participant as: Annualized consumption = (Total IU/kg of rFIXFc during efficacy period (EP) divided by total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc according to the treatment regimens of the study excluding surgical/rehabilitation periods and large injection intervals (\> 28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Countries

Australia, Denmark, France, Ireland, Italy, Netherlands, New Zealand, Poland, Sweden, United Kingdom, United States

Participant flow

Recruitment details

The study was conducted at 28 active centers in 11 countries. Participants were screened between 13-Nov-2014 to 23-Jul-2018.

Pre-assignment details

A total of 38 participants were screened. A total of 33 participants were enrolled, 22 participants began study participation on episodic treatment regimen and 11 participants began study participation on prophylactic treatment regimen.

Participants by arm

ArmCount
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)
Participants received rFIXFc IV injection as follows: Prophylactic treatment regimen: started with rFIXFc 50 IU/kg weekly until a participant reached at least 50 exposure days (ED=24-hour period in which \>=1 injection/dose of rFIXFc was given) to rFIXFc, withdrawal from study or end of study. Adjustments to dose and dosing interval was based on incremental recovery, subsequent Factor IX levels, physical activity, bleeding pattern, in accordance with local standards of care for prophylactic regimen (PR). Treatment with episodic (on demand) regimen can be initiated before PR at investigators discretion. Episodic (On demand; optional): rFIXFc at individual doses based on participant's clinical condition, type and severity of bleeding event until PR.
33
Total33

Withdrawals & dropouts

PeriodReasonFG000
Overall StudyAdverse Event1
Overall StudyEligibility Criteria not fulfilled2
Overall StudyPhysician Decision1
Overall StudyWithdrawal by Subject2

Baseline characteristics

CharacteristicRecombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)
Age, Continuous0.60 years
Race/Ethnicity, Customized
American Indian or Alaska Native
0 Participants
Race/Ethnicity, Customized
Asian
1 Participants
Race/Ethnicity, Customized
Black or African-American
1 Participants
Race/Ethnicity, Customized
Native Hawaiian or other Pacific Islander
0 Participants
Race/Ethnicity, Customized
Other
4 Participants
Race/Ethnicity, Customized
Unknown or Not reported
5 Participants
Race/Ethnicity, Customized
White
22 Participants
Sex: Female, Male
Female
0 Participants
Sex: Female, Male
Male
33 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
0 / 33
other
Total, other adverse events
27 / 33
serious
Total, serious adverse events
23 / 33

Outcome results

Primary

Percentage of Participants With Confirmed Inhibitor Development as Measured by the Nijmegen-Modified Bethesda Assay

Development of an inhibitor was defined as an inhibitor test result of \>= 0.60 Bethesda units per milliliter (BU/mL) that was confirmed by a second test result of \>=0.60 BU/mL from a separate sample, drawn 2 to 4 weeks after the date when the original sample was drawn, with both tests performed by the central laboratory using Nijmegen-modified Bethesda assay.

Time frame: Up to 3 years

Population: Analysis performed on Safety Analysis set which included all participants who had received at least 1 dose of study treatment.

ArmMeasureValue (NUMBER)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Percentage of Participants With Confirmed Inhibitor Development as Measured by the Nijmegen-Modified Bethesda Assay3.03 percentage of participants
Secondary

Annualized Number of Bleeding Episodes (Spontaneous and Traumatic) Per Participant (Annualized Bleeding Rate [ABR])

ABR was annualized number of bleeding episodes during efficacy period (EP) per participant normalized to a 1-year interval of time. Bleeding episodes were classified as: spontaneous if parent/caregiver/participant records bleeding event when there is no known contributing factor such as definite trauma or antecedent strenuous activity; and traumatic when there is known reason for bleed. ABR=(Number of bleeding episodes during EP/total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc per treatment regimens excluding surgical/rehabilitation periods and large injection intervals (greater than \[\>\]28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on Full Analysis Set (FAS) which included all enrolled participants with at least 1 dose of study treatment. Here, number analyzed signifies number of FAS participants who were analyzed in each treatment regimen.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Annualized Number of Bleeding Episodes (Spontaneous and Traumatic) Per Participant (Annualized Bleeding Rate [ABR])Episodic regimen0.21 episodes per participant per year
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Annualized Number of Bleeding Episodes (Spontaneous and Traumatic) Per Participant (Annualized Bleeding Rate [ABR])Prophylaxis regimen1.24 episodes per participant per year
Secondary

Annualized Number of Spontaneous Joint Bleeding Episodes

Bleeding episodes were classified as spontaneous if parent/caregiver/participant records a bleeding event when there is no known contributing factor such as a definite trauma or antecedent strenuous activity. Annualized spontaneous joint bleeding episodes=(Total number of spontaneous joint bleeding episodes during efficacy period (EP) divided by total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc per treatment regimen excluding major and minor surgical/rehabilitation periods and large injection intervals (\>28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on FAS. Here, number analyzed signifies number of FAS participants who were analyzed in each treatment regimen.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Annualized Number of Spontaneous Joint Bleeding EpisodesEpisodic regimen0.00 episodes per participant per year
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Annualized Number of Spontaneous Joint Bleeding EpisodesProphylaxis regimen0.00 episodes per participant per year
Secondary

Average Dose Per Injection of rFIXFc Required to Resolve a Bleeding Episode

The average dose of rFIXFc per injection per bleeding episode was calculated as the average of all doses (IU/kg) administered to treat the bleeding episode during efficacy period (EP). EP begins with the first treatment regimen dose of rFIXFc and ends with the last dose (regardless of the reason for dosing). Surgery/rehabilitation periods are not included in the EP. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on FAS. Here, number analyzed signifies number of bleeding episodes reported for each treatment regimen.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Average Dose Per Injection of rFIXFc Required to Resolve a Bleeding EpisodeEpisodic regimen88.50 IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Average Dose Per Injection of rFIXFc Required to Resolve a Bleeding EpisodeProphylaxis regimen71.92 IU/kg
Secondary

Change From Baseline in rFIXFc Incremental Recovery (IR)

Blood samples were taken at trough and Cmax (maximum concentration) for assessment of incremental recovery, measured by the one-stage clotting assay. IR (International Units per deciliter \[IU/dL\] per IU/kg) = (Cmax for FIX activity - Pre-dose FIX activity) (IU/dL)/ Actual dose (IU/kg), where Cmax is 30 minute FIX activity post-dose and FIX activity less than (\<)0.5 IU/dL was set to 0 IU/dL for calculation of IR.

Time frame: Baseline, Weeks 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, and 144

Population: Analysis performed on FAS. Here number analyzed signifies number of FAS participants with available data for each visit.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 120.0 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 240.0 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 36-0.0 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 48-0.0 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 60-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 72-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 84-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 96-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 108-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 120-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 132-0.1 IU/dL per IU/kg
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Change From Baseline in rFIXFc Incremental Recovery (IR)Change at Week 1440.0 IU/dL per IU/kg
Secondary

Number of Injections of rFIXFc Required to Resolve a Bleeding Episode

Number of injections of rFIXFc required to resolve a bleeding episode during efficacy period (EP) were reported. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc according to the treatment regimens of the study excluding surgical/rehabilitation periods and large injection intervals (\>28 days). All injections given from the initial sign of a bleed, until the last date/time within the bleed window were counted. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on FAS. Here, number analyzed signifies number of bleeding episodes reported for each treatment regimen.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of Injections of rFIXFc Required to Resolve a Bleeding EpisodeEpisodic regimen1.0 injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of Injections of rFIXFc Required to Resolve a Bleeding EpisodeProphylaxis regimen1.0 injections
Secondary

Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point Scale

Using e-diary, each participant's parent/caregiver rated treatment response to any bleeding episode (BE) at approximately 8 to 12 hours from time of injection and prior to additional doses of rFIXFc given for same BE using 4-point scale:- 1=Excellent: abrupt pain relief and/or improvement in signs of bleeding within approximately 8 hours after initial injection; 2=Good: definite pain relief and/or improvement in signs of bleeding within approx. 8 hours after injection, but possibly requiring more than 1 injection after 24-48 hours for complete resolution; 3=Moderate: Probable/slight beneficial effect within 8 hours after initial injection and requires more than 1 injection and 4=None: No improvement or condition worsens within approx. 8 hours after initial injection. Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on FAS. Analysis was based on all injections. Here, number analyzed signifies number of responses to injections reported for each treatment regimen.

ArmMeasureGroupCategoryValue (COUNT_OF_UNITS)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleEpisodic regimenExcellent or Good22 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleEpisodic regimenModerate0 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleEpisodic regimenNone0 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleEpisodic regimenResponse not provided58 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleProphylaxis regimenExcellent or Good50 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleProphylaxis regimenModerate6 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleProphylaxis regimenNone1 responses to injections
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Number of rFIXFc Injections With Excellent or Good, Moderate or None Treatment Response Assessed Using a 4-Point ScaleProphylaxis regimenResponse not provided17 responses to injections
Secondary

Total Annualized rFIXFc Consumption Per Participant for the Prevention and Treatment of Bleeding Episodes

Total annualized rFIXFc consumption (in IU/kg) was calculated for each participant as: Annualized consumption = (Total IU/kg of rFIXFc during efficacy period (EP) divided by total number of days during EP)\*365.25. EP reflects the sum of all intervals of time during which participants were treated with rFIXFc according to the treatment regimens of the study excluding surgical/rehabilitation periods and large injection intervals (\> 28 days). Participants were included in summary of more than 1 treatment regimen if their regimen changed during study.

Time frame: Up to 3 years

Population: Analysis performed on FAS. Here, number analyzed signifies number of FAS participants who were analyzed in each treatment regimen.

ArmMeasureGroupValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Total Annualized rFIXFc Consumption Per Participant for the Prevention and Treatment of Bleeding EpisodesEpisodic regimen203.2 IU per kilogram per participant per year
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Total Annualized rFIXFc Consumption Per Participant for the Prevention and Treatment of Bleeding EpisodesProphylaxis regimen3175.0 IU per kilogram per participant per year
Secondary

Total Number of Exposure Days (EDs)

An ED was defined as a 24-hour period in which a participant received one or more doses of rFIXFc injections, with the time of the first injection of rFIXFc defined as the start of the ED. Participant who did not have a particular injection type were counted as having zero injections for that type.

Time frame: Up to 3 years

Population: Analysis performed on safety analysis set.

ArmMeasureValue (MEDIAN)
Recombinant Coagulation Factor IX Fc Fusion Protein (rFIXFc)Total Number of Exposure Days (EDs)76.0 days

Source: ClinicalTrials.gov · Data processed: Feb 14, 2026