A Study to Assess the Safety and Efficacy of Etrasimod in Subjects With Moderate-to-Severe Atopic Dermatitis

EASI-75 is defined as a 75% reduction or greater in EASI score from Baseline to Week 12. Baseline is defined as Day 1 pre-randomization assessments.

The vIGA scale for AD is a 5-point scale to measure disease severity. The vIGA score was selected using descriptors that best described the overall appearance of skin lesions at a given time point using the following scoring: 0 = clear (no inflammatory signs of AD); 1 = almost clear (barely perceptible erythema and papulation); 2 = mild (slight but definite erythema and papulation); 3 = moderate (clearly perceptible erythema and papulation); and 4 = severe (marked erythema and papulation); Higher score indicated greater severity. Baseline is defined as Day 1 pre-randomization assessments.

Pruritus NRS is an assessment tool that was used to report the intensity of a participant's pruritus (itch). The scale for the pruritus NRS ranged from 0 to 10 with 0 being "no itch" and 10 being "the worst itch imaginable; higher scores indicated greater severity. Baseline is defined as Day 1 pre-randomization assessments.

Pruritus NRS is an assessment tool that was used to report the intensity of a participant's pruritus (itch). The scale for the pruritus NRS ranged from 0 to 10 with 0 being "no itch" and 10 being "the worst itch imaginable; higher scores indicated greater severity. Percentage of participants with improvement (reduction) in peak pruritus NRS >=3 from an itch daily diary is presented. Baseline is defined as Day 1 pre-randomization assessments.

EASI-50 is defined as a 50% reduction or greater of EASI from Baseline to Week 12. Percentage of participants achieving EASI-50 is presented. Baseline is defined as Day 1 pre-randomization assessments.

EASI-90 is defined as as a 90% reduction or greater of EASI from Baseline to Week 12. Percentage of participants achieving EASI-90 is presented Baseline is defined as Day 1 pre-randomization assessments.

BSA affected by AD were assessed for each section of the body. The possible highest score for each region was: head and neck (9%), anterior trunk (18%), back (18%), upper limbs (18%), lower limbs (36%), and genitals (1%) and were reported as a percentage of all major body sections combined; higher % BSA indicated greater severity. Baseline is defined as Day 1 pre-randomization assessments

EASI evaluates severity of participant's AD based on severity of AD clinical signs and percent (%) of body surface area (BSA) affected. EASI is a composite scoring assessment of the affected area in 4 specific disease characteristics (erythema, thickness [induration, papulation, edema], scratching [excoriation], and lichenification), which was each assessed on a scale of "0" (absent) through "3" (severe). The EASI Area Score is documented for 4 regions of the body. Region 1: head and neck; Region 2: trunk (including genital area); Region 3: upper limbs; and Region 4: lower limbs (including buttocks), with the area of AD involvement assessed as a percentage by body area and converted to a score of 0 to 6. Total EASI score ranged from 0 to 72; higher score indicated greater severity of AD. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.

EASI evaluates severity of participant's AD based on severity of AD clinical signs and percent (%) of body surface area (BSA) affected. EASI is a composite scoring assessment of the affected area in 4 specific disease characteristics (erythema, thickness [induration, papulation, edema], scratching [excoriation], and lichenification), which was each assessed on a scale of "0" (absent) through "3" (severe). The EASI Area Score is documented for 4 regions of the body. Region 1: head and neck; Region 2: trunk (including genital area); Region 3: upper limbs; and Region 4: lower limbs (including buttocks), with the area of AD involvement assessed as a percentage by body area and converted to a score of 0 to 6. Total EASI score ranged from 0 to 72; higher score indicated greater severity of AD. EASI-75 is defined as a >=75% reduction or greater of EASI from Baseline.

The vIGA scale for AD is a 5-point scale to measure disease severity. The vIGA score was selected using descriptors that best described the overall appearance of skin lesions at a given time point using the following scoring: 0 = clear (no inflammatory signs of AD); 1 = almost clear (barely perceptible erythema and papulation); 2 = mild (slight but definite erythema and papulation); 3 = moderate (clearly perceptible erythema and papulation); and 4 = severe (marked erythema and papulation); Higher score indicated greater severity.

The SCORAD is a validated measure of the extent and severity of AD using 3 components: A = extent or affected BSA, B = severity and C = subjective symptoms. The extent of AD was assessed as percentage of each defined body area and reported as the sum of all areas, with a maximum score of 100%. The severity of 6 specific symptoms was assessed using the following scale: none (0), mild (1), moderate (2), or severe (3) (for a maximum of 18 total points, assigned as "B" in the overall SCORAD calculation). Subjective assessment of itch and sleeplessness was recorded for each symptom by the participant or relative on a Visual Analogue Scale, where 0 is no itch (or sleeplessness) and 10 is the worst imaginable itch (or sleeplessness), with a maximum possible score of 20. This parameter is assigned as "C" in the overall SCORAD calculation. The total SCORAD ranged from 0 (no disease) to 103 (severe disease); higher score indicated more severe AD.

BSA affected by AD were assessed for each section of the body. The possible highest score for each region was: head and neck (9%), anterior trunk (18%), back (18%), upper limbs (18%), lower limbs (36%), and genitals (1%) and were reported as a percentage of all major body sections combined; higher % BSA indicated greater severity. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.

Pruritus NRS is an assessment tool that was used to report the intensity of a participant's pruritus (itch). The scale for the pruritus NRS ranged from 0 to 10 with 0 being "no itch" and 10 being "the worst itch imaginable; higher scores indicated greater severity. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.

The POEM is a participant-derived validated tool used for monitoring atopic eczema severity. The POEM consisted of 7 questions asking participants to rank how many days over the past 7 days they had experienced specific AD-related symptoms. Each of the 7 questions carried equal weight and was scored from 0 to 4 as follows: No days = 0; 1-2 days = 1; 3-4 days = 2; 5-6 days = 3; Every day = 4. The scores from the 7 questions were added up to give an overall POEM score as: 0-2 = 'clear/almost clear', 3-7 = 'mild', 8-16 = 'moderate', 17-24 = 'severe', and 25-28 = 'very severe atopic eczema'; higher scores indicated worse atopic eczema severity. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.

The DLQI is a validated 10-item questionnaire designed to measure the impact of skin disease on the Quality of Life (QoL). DLQI is a response to 10 items, which assessed QoL over the past week. For each item, the scale was rated as follows: 0 = "not at all"; 1 = "a little"; 2 = "a lot"; 3 = "very much," with an overall scoring system of 0 to 30; higher scores indicated a poor QoL. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.

PGA is an assessment tool that was used by participant to rate the disease and disease severity. Participants rated their overall well-being based on a 5-point Likert scale from poor to excellent. Response choices were: 1- 'Poor', 2- 'Fair', 3- 'Good', 4- 'Very Good,' or 5- 'Excellent'; higher scores indicated better well-being. For the 5-point Likert scale, a positive change from baseline indicates an improvement. Baseline is defined as the last measurement prior to the first etrasimod dose started at Week 16.