Trial · NCT03417245

A Study of Fitusiran (ALN-AT3SC) in Severe Hemophilia A and B Patients Without Inhibitors

NCT03417245, Phase 3, Completed, Genzyme, a Sanofi Company; results first posted 2022-02-04

3 sourcestrials-2026-11-12-0.5.0

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ConductScience Library. A Study of Fitusiran (ALN-AT3SC) in Severe Hemophilia A and B Patients Without Inhibitors. Trials, record NCT03417245. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT03417245

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: A Study of Fitusiran (ALN-AT3SC) in Severe Hemophilia A and B Patients Without Inhibitors
NCT number: NCT03417245
Status: Completed
Phases: Phase 3
Enrollment: 120 participants, actual
Lead sponsor: Genzyme, a Sanofi Company
Conditions: Hemophilia A, Hemophilia B
Interventions: fitusiran, factor concentrates
First posted: 2018-01-31
Last updated: 2022-03-28
Other registries' IDs: eudract:2016-001464-11
Results first posted: 2022-02-04

Source ClinicalTrials.gov

Registered outcomes12

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	ABR for a participant during efficacy period (EP) was defined as annualized number of bleeding episodes during EP annualized to a 1-year interval of time. Treated Bleeding episode: any occurrence of hemorrhage that required administration of by-passing agents (BPA) or factor. It started from first sign of a bleed and ended no more than 72 hours after last treatment for bleed, within which any symptoms of bleeding at same location or injections less than or equal to (\<=) 72 hours apart were considered the same bleeding episode. EP was defined as time duration starting from Day 29 when antithrombin (AT) lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246). This outcome measure (OM) presents estimated results (i.e., results received by applying negative binomial \[NB\] regression model on data collected during EP).
Primary	Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	ABR for a participant during EP was defined as annualized number of bleeding episodes during EP annualized to a 1-year interval of time. ABR= number of bleeding episodes during EP divided by total number of days during EP\*365.25. A bleeding episode was defined as any occurrence of hemorrhage that required administration of BPA or factor. It started from the first sign of a bleed and ended no more than 72 hours after the last treatment for the bleed, within which any symptoms of bleeding at the same location or injections \<=72 hours apart were considered the same bleeding episode. EP was defined as time duration starting from Day 29 when the AT lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or the last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246). This OM presents observed results (i.e., descriptive statistics values based on the data collected during EP).
Secondary	Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	From Day 1 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	ABR for a participant during treatment period (TP) was defined as annualized number of bleeding episodes during TP annualized to a 1-year interval of time. Bleeding episode: any occurrence of hemorrhage that required administration of BPA or factor. It started from first sign of a bleed and ended no more than 72 hours after last treatment for bleed, within which any symptoms of bleeding at same location or injections \<=72 hours apart were considered the same bleeding episode. TP was sum of onset period (first 28 days after first dose of fitusiran) and EP (starting on Day 29 when AT lowering capacity of fitusiran had achieved therapeutic target range to earliest of Day 246 or last day of bleeding follow up (maximum duration of TP: from Day 1 to Day 246). This OM presents estimated results (i.e., results received by applying NB regression model on data collected during TP).
Secondary	Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	From Day 1 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	ABR for a participant during TP was defined as annualized number of bleeding episodes during TP annualized to a 1- year interval of time. ABR= number of bleeding episodes during TP divided by total number of days during TP\*365.25. Bleeding episode: any occurrence of hemorrhage that required administration of BPA or factor. It started from the first sign of a bleed and ended no more than 72 hours after last treatment for bleed, within which any symptoms of bleeding at the same location or injections \<=72 hours apart were considered the same bleeding episode. TP was sum of onset period (first 28 days after the first dose of fitusiran) and EP (starting on Day 29 when AT lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or the last day of bleeding follow up (maximum duration of TP: from Day 1 to Day 246). This OM presents observed results (i.e., descriptive statistics values based on data collected during TP).
Secondary	Estimated Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Annualized spontaneous bleeding rate for a participant during EP was defined as annualized number of spontaneous bleeding episodes during EP annualized to a 1-year interval of time. Spontaneous bleeding episode was bleeding event that occurred for no apparent or known reason, particularly into joints, muscles, and soft tissues. It started from first sign of a bleed and ended no more than 72 hours after last treatment for the bleed, within which any symptoms of bleeding at the same location or injections \<=72 hours apart were considered the same bleeding episode. EP was defined as time duration starting from Day 29 when AT lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246). This OM presents estimated results (i.e., results received by applying NB regression model on data collected during EP).
Secondary	Observed Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	ABR for participant during EP was defined as annualized number of spontaneous bleeding episodes during EP annualized to a 1-year interval of time. ABR=number of treated spontaneous bleeding episodes during EP divided by total number of days during EP\*365.25. Spontaneous bleeding episode was bleeding event that occurred for no apparent or known reason, into joints, muscles, and soft tissues. It started from the first sign of a bleed and ended no more than 72 hours after the last treatment for the bleed, within which any symptoms of bleeding at the same location or injections \<=72 hours apart were considered the same bleeding episode. EP: time duration starting from Day 29 when the AT lowering capacity of fitusiran had achieved therapeutic target range to earliest of Day 246 or the last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246).This OM presents observed results (i.e., descriptive statistics values based on data collected during EP).
Secondary	Estimated Annualized Joint Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Annualized joint bleeding rate for a participant during EP was defined as annualized number of bleeding episodes during EP annualized to a 1-year interval of time. Joint bleeding episode was characterized by an unusual sensation in the joint ("aura") in combination with 1) increasing swelling or warmth over the skin, joint, 2) increasing pain, or 3) progressive loss of range of motion or difficulty in using the limb as compared with Baseline. It started from first sign of a bleed and ended no more than 72 hours after last treatment for the bleed. EP was defined as time duration starting from Day 29 when the AT lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or the last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246). This OM presents estimated results (i.e., results received by applying NB regression model on data collected during EP).
Secondary	Observed Annualized Joint Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Annualized joint bleeding rate for participant during EP was defined as annualized number of joint bleeding episodes during EP annualized to 1-year interval of time. ABR= number of treated joint bleeding episodes during EP divided by total number of days during EP\*365.25. A joint bleeding episode was characterized by an unusual sensation in joint ("aura") in combination with 1) increasing swelling or warmth over skin, joint, 2) increasing pain, or 3) progressive loss of range of motion or difficulty in using limb as compared with Baseline. It started from first sign of a bleed and ended no more than 72 hours after the last treatment for the bleed. EP: time duration starting from Day 29 when the AT lowering capacity of fitusiran had achieved therapeutic target range to the earliest of Day 246 or last day of bleeding follow up (maximum duration of EP: from Day 29 to Day 246). This OM presents observed results (i.e., descriptive statistics values based on data collected during EP).
Secondary	Health-related Quality of Life (HRQOL): Change From Baseline in Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QOL) Physical Health Score at Month 9	Baseline (Day 1), Month 9	Haem-A-QoL: participant-reported questionnaire designed for adult participants (\>=17 years of age) with hemophilia; and consisted of 46 items comprising 10 domains (physical health, feelings, view of yourself, sports and leisure, work and school, dealing with hemophilia, treatment, future, family planning, partnership and sexuality). Scoring for each item was based on a 5-point Likert scale (1= never, 2= rarely, 3= sometimes, 4= often, and 5=all the time), and higher scores represented greater impairment. Change from baseline in physical health domain score was reported in this outcome measure. Raw score for physical health domain were transformed to a scale ranged from 0 (better health outcome) to 100 (worst health outcome), where lower scores denoted better physical health.
Secondary	Health-related Quality of Life (HRQOL): Change From Baseline in Haem-A-QOL Total Score at Month 9	Baseline (Day 1), Month 9	Haem-A-QoL: participant-reported questionnaire designed for adult participants (\>=17 years of age) with hemophilia; and consisted of 46 items comprising 10 domains (physical health, feelings, view of yourself, sports and leisure, work and school, dealing with hemophilia, treatment, future, family planning, partnership and sexuality). Scoring for each item was based on a 5-point Likert scale (1= never, 2= rarely, 3= sometimes, 4= often, and 5=all the time), and higher scores represent greater impairment. Raw score for each domain were transformed to a scale ranged between 0 and 100, where lower scores denoted better health. Haem-A-QoL total score was average of all domain scores and ranged from 0 (better health outcome) to 100 (worst health outcome), where lower scores denoted better physical health.

1 to 10 of 12Source ClinicalTrials.gov

See all 12 registered outcomes

Outcomes12

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	NUMBER
PRIMARY	Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	MEDIAN
SECONDARY	Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	From Day 1 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	NUMBER
SECONDARY	Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	From Day 1 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	MEDIAN
SECONDARY	Estimated Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	NUMBER
SECONDARY	Observed Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	MEDIAN
SECONDARY	Estimated Annualized Joint Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	NUMBER
SECONDARY	Observed Annualized Joint Bleeding Rate for Treated Bleeds During the Efficacy Period	From Day 29 up to Day 246 or up to the last day of bleeding follow up (any day up to Day 246), whichever was the earliest	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	episodes per participant per year	MEDIAN
SECONDARY	Health-related Quality of Life (HRQOL): Change From Baseline in Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QOL) Physical Health Score at Month 9	Baseline (Day 1), Month 9	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	scores on a scale	LEAST_SQUARES_MEAN
SECONDARY	Health-related Quality of Life (HRQOL): Change From Baseline in Haem-A-QOL Total Score at Month 9	Baseline (Day 1), Month 9	Analysis was performed on ITT population. Here, overall number of participants analyzed = participants evaluable for this outcome measure.	scores on a scale	LEAST_SQUARES_MEAN

1 to 10 of 12Source ClinicalTrials.gov

See all 12 outcomes

Results by group26

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	Factor On-demand	30.991	95% Confidence Interval 21.114 to 45.487	episodes per participant per year
Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	Fitusiran 80 mg Prophylaxis	3.133	95% Confidence Interval 2.269 to 4.326	episodes per participant per year
Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	Factor On-demand	21.8	Inter-Quartile Range 8.4 to 41.0	episodes per participant per year
Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Efficacy Period	Fitusiran 80 mg Prophylaxis	0.0	Inter-Quartile Range 0.0 to 3.4	episodes per participant per year
Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	Factor On-demand	31.444	95% Confidence Interval 22.995 to 42.999	episodes per participant per year
Estimated Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	Fitusiran 80 mg Prophylaxis	4.092	95% Confidence Interval 3.143 to 5.328	episodes per participant per year
Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	Factor On-demand	25.2	Inter-Quartile Range 11.9 to 43.8	episodes per participant per year
Observed Annualized Bleeding Rate (ABR) for Treated Bleeds During the Treatment Period	Fitusiran 80 mg Prophylaxis	1.8	Inter-Quartile Range 0.0 to 4.5	episodes per participant per year
Estimated Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	Factor On-demand	22.036	95% Confidence Interval 14.159 to 34.295	episodes per participant per year
Estimated Annualized Spontaneous Bleeding Rate for Treated Bleeds During the Efficacy Period	Fitusiran 80 mg Prophylaxis	1.825	95% Confidence Interval 1.237 to 2.692	episodes per participant per year

1 to 10 of 26Source ClinicalTrials.gov

See all 26 results by group

Participant flow8

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Factor On-demand	40
Overall Study	STARTED	Fitusiran 80 mg Prophylaxis	80
Overall Study	Treated	Factor On-demand	40
Overall Study	Treated	Fitusiran 80 mg Prophylaxis	79
Overall Study	COMPLETED	Factor On-demand	37
Overall Study	COMPLETED	Fitusiran 80 mg Prophylaxis	79
Overall Study	NOT COMPLETED	Factor On-demand	3
Overall Study	NOT COMPLETED	Fitusiran 80 mg Prophylaxis	1

Source ClinicalTrials.gov

Adverse events52

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk	Events
other	Alanine Aminotransferase Increased	Investigations	Factor On-demand	1	40	1
other	Alanine Aminotransferase Increased	Investigations	Fitusiran 80 mg Prophylaxis	18	79	20
other	Aspartate Aminotransferase Increased	Investigations	Factor On-demand	2	40	2
other	Aspartate Aminotransferase Increased	Investigations	Fitusiran 80 mg Prophylaxis	6	79	7
other	Blood Bilirubin Increased	Investigations	Factor On-demand	0	40	0
other	Blood Bilirubin Increased	Investigations	Fitusiran 80 mg Prophylaxis	4	79	4
other	Headache	Nervous system disorders	Factor On-demand	0	40	0
other	Headache	Nervous system disorders	Fitusiran 80 mg Prophylaxis	5	79	6
other	Abdominal Pain	Gastrointestinal disorders	Factor On-demand	1	40	1
other	Abdominal Pain	Gastrointestinal disorders	Fitusiran 80 mg Prophylaxis	6	79	6

1 to 10 of 52Source ClinicalTrials.gov

See all 52 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Factor On-demand	0	40
Total, all-cause mortality	Fitusiran 80 mg Prophylaxis	0	79
Total, other adverse events	Factor On-demand	8	40
Total, other adverse events	Fitusiran 80 mg Prophylaxis	45	79
Total, serious adverse events	Factor On-demand	5	40
Total, serious adverse events	Fitusiran 80 mg Prophylaxis	5	79

Source ClinicalTrials.gov

Papers2

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
34922648	DERIVED	PubMed
37003278	DERIVED	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons2

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison	Source
Factor On-demand vs Fitusiran 80 mg Prophylaxis: deaths from any cause	Trial comparisons
Factor On-demand vs Fitusiran 80 mg Prophylaxis: serious adverse events	Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

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