A Study to Evaluate the Efficacy and Safety of Subcutaneous Amlitelimab on Background Topical Corticosteroids Therapy in Participants Aged 12 Years and Older With Moderate-to-severe AD Who Have Had an Inadequate Response to Prior Biologic Therapy or an Oral JAK Inhibitor

Proportion of participants reaching EASI-75 at Week 36 (for US and US reference countries only)

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-75 is 75% reduction from baseline in EASI score.

Time frame: Week 36

Proportion of participants with vIGA-AD 0 (clear) or 1 (almost clear) with presence of only barely perceptible erythema (no induration/papulation, no lichenification, no oozing or crusting and a reduction from baseline of ≥2 points)

The vIGA-AD is an Investigator-completed assessment scale used to determine severity of AD and clinical response to treatment. It is based on a 5-point scale, ranging from 0 (clear) to 4 (severe).

Time frame: Baseline to Week 36

Proportion of participants with ≥4-point reduction in weekly average of daily Peak Pruritus-Numerical Rating Scale (PP-NRS) from baseline in participants with baseline weekly average of daily PP-NRS ≥4

The PP-NRS is a validated single item 0-10 numeric rating scale assessing peak pruritus (itch) associated with AD with 0 = no itch and 10 = worst itch imaginable.

Time frame: Baseline to Week 36

Proportion of participants reaching EASI-75

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-75 is 75% reduction from baseline in EASI score.

Time frame: Baseline to Week 24

Proportion of participants with vIGA-AD of 0 (clear) or 1 (almost clear) and a reduction from baseline of ≥2 points

The vIGA-AD is an Investigator-completed assessment scale used to determine severity of AD and clinical response to treatment. It is based on a 5-point scale, ranging from 0 (clear) to 4 (severe).

Time frame: Baseline to Week 24

Proportion of participants reaching EASI-90

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-90 is 90% reduction from baseline in EASI score.

Time frame: Baseline to Week 36

Proportion of participants reaching EASI-100

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-100 is 100% reduction from baseline in EASI score.

Time frame: Baseline to Week 36

Proportion of participants with PP-NRS ≤1

The PP-NRS is a validated single item 0-10 numeric rating scale assessing peak pruritus (itch) associated with AD with 0 = no itch and 10 = worst itch imaginable.

Time frame: Baseline to Week 36

Change in Dermatology Life Quality Index (DLQI) from baseline in participants with age ≥16 years old

The DLQI is a validated 10-item questionnaire to measure dermatology-specific quality of life (QoL) in adult patients. Overall scoring ranges from 0 to 30, with a higher score indicating a poorer QoL.

Time frame: Baseline to Week 36

Proportion of participants with a reduction in DLQI ≥4 from baseline in participants with age ≥16 years old and with DLQI baseline ≥4

The DLQI is a validated 10-item questionnaire to measure dermatology-specific quality of life (QoL) in adult patients. Overall scoring ranges from 0 to 30, with a higher score indicating a poorer QoL.

Time frame: Baseline to Week 36

Change in Children Dermatology Life Quality Index (CDLQI) from baseline in participants with age ≥12 to <16 years

The CDLQI is a validated 10-item questionnaire to measure dermatology-specific quality of life (QoL) in children aged 4-\<16 years. Overall scoring ranges from 0 to 30, with a higher score indicating a poorer QoL.

Time frame: Baseline to Week 36

Proportion of participants with a reduction in CDLQI ≥6 from baseline in participants with age ≥12 to <16 years old and with CDLQI baseline ≥6

The CDLQI is a validated 10-item questionnaire to measure dermatology-specific quality of life (QoL) in children aged 4-\<16 years. Overall scoring ranges from 0 to 30, with a higher score indicating a poorer QoL.

Time frame: Baseline to Week 36

Change in Hospital Anxiety Depression Scale (HADS) from baseline

The HADS is 14-item questionnaire with two subscales: anxiety \& depression. Each subscale (anxiety \& depression) ranges 0-21. The total HADS score ranges 0-42 with higher score indicating a poorer state.

Time frame: Baseline to Week 36

Proportion of participants with HADS subscale Anxiety (HADS-A) <8 in participants with baseline HADS-A ≥8

HADS-A score ranges 0-21 with higher score indicating a poorer state.

Time frame: Baseline to Week 36

Proportion of participants with HADS subscale Depression (HADS-D) <8 in participants with HADS-D baseline ≥8

HADS-D score ranges 0-21 with higher score indicating a poorer state.

Time frame: Baseline to Week 36

Absolute change in weekly average of daily Skin Pain-Numerical Rating Scale (SP-NRS) from baseline

The SP-NRS is a single item 0-10 numeric rating scale assessing skin pain associated with AD with 0 = no pain and 10 = worst possible pain imaginable.

Time frame: Baseline to Week 36

Proportion of participants with a reduction in weekly average of daily SP-NRS ≥4 from baseline in participants with baseline weekly average of daily SP-NRS ≥4

The SP-NRS is a single item 0-10 numeric rating scale assessing skin pain associated with AD with 0 = no pain and 10 = worst possible pain imaginable.

Time frame: Baseline to Week 36

Percent change in weekly average of daily SP-NRS from baseline

The SP-NRS is a single item 0-10 numeric rating scale assessing skin pain associated with AD with 0 = no pain and 10 = worst possible pain imaginable.

Time frame: Baseline to Week 36

Proportion of participants with vIGA-AD 0 (clear)

The vIGA-AD is an Investigator-completed assessment scale used to determine severity of AD and clinical response to treatment. It is based on a 5-point scale, ranging from 0 (clear) to 4 (severe).

Time frame: Baseline to Week 36

Absolute change in weekly average of daily Sleep Disturbance-Numerical Rating Scale (SD-NRS) from baseline

The SD-NRS is a single item 0-10 numeric rating scale assessing sleep disturbance associated with AD with 0 = no sleep loss and 10 = did not sleep at all.

Time frame: Baseline to Week 36

Proportion of participants with a reduction in weekly average of daily SD-NRS ≥3 from baseline in participants with Baseline weekly average of daily SD-NRS ≥3

The SD-NRS is a single item 0-10 numeric rating scale assessing sleep disturbance associated with AD with 0 = no sleep loss and 10 = did not sleep at all.

Time frame: Baseline to Week 36

Percent change in weekly average of daily SD-NRS

The SD-NRS is a single item 0-10 numeric rating scale assessing sleep disturbance associated with AD with 0 = no sleep loss and 10 = did not sleep at all.

Time frame: Baseline to Week 36

Percent change in EASI score from baseline

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD.

Time frame: Baseline to Week 36

Percent change in weekly average of daily PP-NRS from baseline

The PP-NRS is a validated single item 0-10 numeric rating scale assessing peak pruritus (itch) associated with AD with 0 = no itch and 10 = worst itch imaginable.

Time frame: Baseline to Week 36

Absolute change in weekly average of daily PP-NRS from baseline

The PP-NRS is a validated single item 0-10 numeric rating scale assessing peak pruritus (itch) associated with AD with 0 = no itch and 10 = worst itch imaginable.

Time frame: Baseline to Week 36

Proportion of participants reaching EASI-50

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-50 is 50% reduction from baseline in EASI score.

Time frame: Baseline to Week 36

Proportion of participants with EASI ≤7

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD.

Time frame: Baseline to Week 36

Change in percent Body Surface Area (BSA) affected by AD from baseline

Time frame: Baseline to Week 36

Percent change in Scoring Atopic Dermatitis (SCORAD) index from baseline

The SCORAD index is a clinical tool to evaluate the extent and severity of AD. Total score ranges from 0 (absent disease) to 103 (severe disease).

Time frame: Baseline to Week 36

Absolute change in SCORAD index from baseline

The SCORAD index is a clinical tool to evaluate the extent and severity of AD. Total score ranges from 0 (absent disease) to 103 (severe disease).

Time frame: Baseline to Week 36

Proportion of participants with a reduction in SCORAD ≥ 8.7 points from baseline in participants with baseline SCORAD score ≥ 8.7

The SCORAD index is a clinical tool to evaluate the extent and severity of AD. Total score ranges from 0 (absent disease) to 103 (severe disease).

Time frame: Baseline to Week 36

Proportion of participants with a reduction in Patient Oriented Eczema Measure (POEM) ≥4 from baseline in participants with POEM Baseline ≥4

The POEM is a 7-item self-assessment questionnaire that assesses disease symptoms on a 5-point scale; 0 (no days) to 4 (every day in the last week). The sum of the 7 items gives the total POEM score of 0 (absent disease) to 28 (very severe). Higher scores indicated more severe disease and poor quality of life.

Time frame: Baseline to Week 36

Change in POEM from baseline

The POEM is a 7-item self-assessment questionnaire that assesses disease symptoms on a 5-point scale; 0 (no days) to 4 (every day in the last week). The sum of the 7 items gives the total POEM score of 0 (absent disease) to 28 (very severe). Higher scores indicated more severe disease and poor quality of life.

Time frame: Baseline to Week 36

Proportion of participants with rescue medication use

Time frame: Baseline to Week 36

Time to onset of effect on PP-NRS as measured by proportion of participants with an improvement (reduction) in PP-NRS by ≥4

The PP-NRS is a validated single item 0-10 numeric rating scale assessing peak pruritus (itch) associated with AD with 0 = no itch and 10 = worst itch imaginable.

Time frame: Baseline to Week 36

Percentage of TCS/TCI free days

Time frame: Baseline to Week 36

Percentage of participants who experienced Treatment-Emergent Adverse Events (TEAEs), experienced Treatment-Emergent Serious Adverse Events (TESAEs) and/or Treatment-Emergent Adverse Events of Special Interest (AESI)

Time frame: Baseline to Week 52

Serum amlitelimab concentrations

Time frame: Baseline to Week 52

Incidence of antidrug antibodies (ADAs) of amlitelimab

Time frame: Baseline to Week 52

Time to onset of effect on vIGA-AD as measured by proportion of participants with vIGA-AD 0 (clear) or 1 (almost clear) and a reduction from baseline ≥2 during the 36-week treatment period

The vIGA-AD is an Investigator-completed assessment scale used to determine severity of AD and clinical response to treatment. It is based on a 5-point scale, ranging from 0 (clear) to 4 (severe).

Time frame: Baseline to Week 36

Time to onset of effect on EASI as measured by proportion of participants reaching a 75% reduction from baseline in EASI score during the 36-week treatment period

The EASI is an Investigator-assessed validated tool used to measure the extent (area) and severity of AD. Total score ranges from 0 to 72 with a higher score indicating increased extent and severity of AD. EASI-75 is 75% reduction from baseline in EASI score.

Time frame: Baseline to Week 36