Efficacy and Safety of Vamifeport in Adult Participants With Homeostatic Iron Regulator Gene (HFE)-Related Hereditary Hemochromatosis

Number of participants with treatment-emergent adverse events (TEAEs)

Time frame: Up to Day 390

Percentage of participants with TEAEs

Time frame: Up to Day 390

Number of participants with treatment-emergent serious adverse events (SAEs)

Time frame: Up to Day 390

Percentage of participants with treatment-emergent SAEs

Time frame: Up to Day 390

Number of participants with clinically significant change from baseline in clinical safety laboratory tests and 12-lead electrocardiogram (ECG)

Clinical safety laboratory tests will include hematology, biochemistry and coagulation.

Time frame: From Baseline to Day 390

Percentage of participants with clinically significant change from baseline in clinical safety laboratory tests and 12-lead ECG

Clinical safety laboratory tests will include hematology, biochemistry and coagulation.

Time frame: From Baseline to Day 390

Change from baseline in transferrin saturation (TSAT) (measured at trough)

Time frame: From Baseline to Day 360

Number of participants with TSAT less than or equal to (<=) 45% (measured at trough)

Time frame: From Baseline to Day 360

Percentage of participants with TSAT <= 45% (measured at trough)

Time frame: From Baseline to Day 360

Number of participants with 25% reduction in MRI-based LIC

Time frame: At Day 180 and 360

Number of participants with 50% reduction in MRI-based LIC

Time frame: At Day 180 and Day 360

Number of participants with TSAT ≤ 45% or MRI-based LIC < 5 milligrams per gram (mg/g)

Time frame: At Day 360

Number of participants with TSAT ≤ 45% or MRI-based LIC < 2 mg/g

Time frame: At Day 360

Change from baseline in joint pain score in a visual analog scale (VAS)

The VAS is a single-item questionnaire. Participants will be asked to record their joint pain at its worst over the previous week, from 0 (No pain) to 10 (Worst possible pain).

Time frame: From Baseline to Day 360

Change from baseline in modified fatigue impact scale (MFIS) total score

Participants will be asked to read a list of 21 statements and assess how often fatigue has affected them in terms of physical, cognitive, and psychosocial functioning, over the previous 4 weeks, using a 5-point scale from 0 (Never) to 4 (Almost always). The total score is obtained by summing the scores of all the 21 items. Higher scores indicate a greater impact of fatigue on a participant's activities.

Time frame: From Baseline to Day 360

Change from baseline in health-related quality of life: EuroQoL 5-dimension 5-level instrument (EQ-5D-5L)

The EQ-5D-5L is a standardized measure of health status that provides a simple, generic measure of health for clinical and economic appraisal. Participants will complete the questionnaire based on their health on that day. The EQ-5D-5L descriptive profile includes 5 dimensions: mobility, self-care, usual activities, pain / discomfort, and anxiety / depression. Participants will rate each dimension based on 5 levels of severity: no problems, slight problems, moderate problems, severe problems, and extreme problems. A higher score indicates a more severe outcome than a lower score.

Time frame: From Baseline to Days 180, 360, and 390

Change from baseline in health-related quality of life: VAS (Arthralgia)

The VAS is a single-item questionnaire. Participants will be asked to record their joint pain at its worst over the previous week, from 0 (No pain) to 10 (Worst possible pain).

Time frame: From Baseline to Day 180, 360, and 390

Change from baseline in health-related quality of life: Patient global impression of change in clinical status

The PGI - Change (PGI-C) instrument is a self-reported measure that reflects belief about the efficacy of treatment. Participants will be asked to rate the change in their overall symptoms since they started taking investigational product (IP) on a 5-point scale, ranging from 1 (Much improved) to 5 (Much worse). A lower score reflects an improvement in clinical status.

Time frame: From Baseline to Day 180, 360, and 390

Change from baseline in health-related quality of life: Patient global impression of severity

The PGI - Severity (PGI-S) instrument is a self-reported questionnaire and consists of 1 item that measures disease severity. Participants will be asked to rate the severity of their overall symptoms over the previous week on a 5-point scale from 1 (None) to 5 (Very severe). A higher score reflects a more severe outcome than a lower score.

Time frame: From Baseline to Day 180, 360, and 390

Change from baseline in health-related quality of life: MFIS physical, cognitive, and psychosocial subscales

Participants will be asked to read a list of 21 statements and assess how often fatigue has affected them in terms of physical, cognitive, and psychosocial functioning, over the previous 4 weeks, using a 5-point scale from 0 (Never) to 4 (Almost always). Items on the MFIS will be aggregated into 3 subscales (Physical, Cognitive, or Psychosocial). Higher scores indicate a greater impact of fatigue on a participant's activities.

Time frame: From Baseline to Day 180, 360, and 390

Vamifeport plasma concentrations after a single dose

Time frame: At Day 1

Vamifeport plasma concentrations at steady state

Time frame: At Days 15, 180, and 360

Change from baseline in total serum iron (measured at trough)

Time frame: From Baseline to Day 360

Change from baseline in serum ferritin (measured at trough)

Time frame: From Baseline to Day 360

Frequency of rescue therapy use

For assessment of this outcome measure, data will be collected retrospectively from 1 year before baseline as well as during the study (up to Day 390).

Time frame: Up to Day 390

Duration of rescue therapy use

For assessment of this outcome measure, data will be collected retrospectively from 1 year before baseline as well as during the study (up to Day 390).

Time frame: Up to Day 390

Time to first use of rescue therapy

Time frame: Up to Day 360