Dupilumab Effect on Pruritus Neuro-mechanisms in Patients With Atopic Dermatitis

Skin biopsies were used to analyze the epidermal nerve fiber density. Nerve fibers were visualized by staining consecutive sections for the pan-axonal marker PGP9.5; and the basement membrane was visualized by staining for collagen type 4. Quantification of intraepidermal nerve fiber density was calculated by assessing nerve fibers crossing the basement membrane per square millimeter (F/mm^2).

Skin biopsies were used to analyze the epidermal nerve fiber branching. Nerve fibers were visualized by staining consecutive sections for the pan-axonal marker PGP9.5; and the basement membrane was visualized by staining for collagen type 4. Branching of epidermal nerve fibers was assessed semi-quantitatively by classifying participants into 4 groups depending on the predominant intraepidermal nerve fiber branching pattern as follows: only linear (100% linear), mainly linear (>60% linear), mainly branched (>60% branched), only branched (100% branched).

Peak Pruritus NRS was an assessment tool used to report the intensity of participant's pruritus (itch) during a daily recall period. Participants were asked to rate their worst itch on a 0 ("No itch") to 10 ("Worst itch imaginable") NRS by answering the following question: "On a scale of 0 to 10, with 0 being 'no itch' and 10 being the 'worst itch imaginable', how would you rate your itch at the worst moment during the previous 24 hours?". Higher scores indicated greater severity.

EASI was a validated measure used to assess the severity and extent of AD. Four AD disease characteristics (erythema, thickness [induration, papulation, and edema], scratching [excoriation], and lichenification) were each assessed for severity by the Investigator on a scale of "0" (absent) through "3" (severe). EASI area score was based upon percent (%) body surface area (BSA) with AD in each body region: 0, 1 (1% to 9%), 2 (10% to 29%), 3 (30% to 49%), 4 (50% to 69%), 5 (70% to 89%), and 6 (90% to 100%). Total EASI score was derived as the sum of the 4 region scores and ranged from 0 (minimum) to 72 (maximum). Higher scores indicated greater severity of AD.

SCORAD was used to standardize the extent and severity of AD. It consisted of 3 components i.e., A =extent or affected BSA assessed as a % of each defined body area and reported as sum of all areas, with a maximum score of 100%. B=severity of 6 specific symptoms of AD (redness, swelling, oozing/crusting, excoriation, skin thickening/lichenification, dryness) assessed using following scale: none (0), mild (1), moderate (2), or severe (3) (for a maximum of 18 total points) and C=subjective symptoms scored by participants on VAS, where "0"=no itch (or no sleeplessness) and "10"=worst imaginable itch (or sleeplessness) with a maximum score of 20. SCORAD total score was calculated using these 3 aspects: extent (A: 0-100), severity (B: 0-18), and subjective symptoms (C: 0-20) using the formula: A/5 + 7*B/2+ C. SCORAD total score ranged from 0 to 103, where 0 = no disease to 103 = severe disease. Higher values of SCORAD represent worse outcome.

PROMIS-itch represents a novel suite of participant-reported outcome (PRO) measures for the itch. The PROMIS-Itch severity score consists of 7 questions: 4 questions scored on a scale of 1 to 5: 1) How intense was your itch at its worst; 2) How intense was your itch in general; 3) What is your level of itch right now; 4) How often did you feel the itch; and rest 3 questions (same questions as 1 to 3 mentioned before but scaled on a scale of 0 to 10) were scored on a scale of 0 to 10. Higher scores for each question indicated worse outcome. The total PROMIS-itch score was calculated as the sum of the 7 questions and ranged from 4 (better outcome) to 50 (worse outcome), where a higher score indicated worse condition.

The POEM was a 7-item, validated questionnaire used in clinical practice and clinical trials to assess disease symptoms in children and adults with AD. The format is participant response to 7 items (dryness, itching, flaking, cracking, sleep loss, bleeding, and weeping) based on symptom frequency during the past week (i.e., 0 = 'no days', 1 = '1 to 2 days', 2 = '3 to 4 days', 3 = '5 to 6' days, and 4 = 'every day'). The sum of the 7 items gives the total POEM score of 0 (absent disease) to 28 (severe disease). Higher scores indicated more severe disease and poor quality of life.

DLQI was a 10-item PRO questionnaire that measured the impact of AD disease symptoms and treatment on quality of life. Each question was evaluated on a 4-point scale ranged from 0 to 3 where, 0 = not at all, 1= a little, 2= a lot, 3= very much, where higher scores indicated more impact on quality of life. Scores from all 10 questions were added up to give DLQI total score that ranged from 0 (not at all) to 30 (very much). Higher scores indicated more impact on quality of life of participants.

ADCT was a PRO questionnaire designed to assess participant-self-perceived control of their eczema. ADCT contained 6 items allowing a comprehensive coverage of the dimensions defining AD control, i.e., overall severity of AD symptoms, frequency of intense episodes of itching, extent of AD related bother, impact on sleep, impact on daily activities, impact on mood or emotions. Each item of the ADCT is rated from 0 (no problem) to 4 (worst) Likert scale and is equally weighted. The sum of the 6 items gives the total score that ranged from 0 (best disease control) to 24 (worst disease control). Higher scores indicate lower AD control.

Sleep quality NRS was used to assess the quality of the participant's previous night's sleep using a 0 ("Worst possible sleep") to 10 ("Best possible sleep") NRS. Participants were asked to complete the following question upon awakening: "Select the number (0 to 10) that best describes the quality of your sleep last night". Higher score indicated better outcome.

Skin pain NRS was used to assess participant's skin pain at its worst in the past 24 hours using a 0 ("Not at all") to 10 ("Very much") NRS. Participants were asked the following question: "Think about all the areas of your skin with eczema. How much did your skin burn at its worst in the past 24 hours?" Lower score indicated better outcome.

Skin sensitivity NRS was a 1 item PRO measure asking the participants to rate their skin sensitivity to touch using a 0 ("Normal") to 10 ("Extremely sensitive") NRS. Participants were asked the following question: "Think about all the areas of your skin with eczema. How sensitive was your skin at its worst in the past 24 hours?" Lower score indicated better outcome.

Skin burning NRS was a 1-item PRO measure asking participants to rate the burning sensation of their skin in the past 24 hours using a 0 ("Not at all") to 10 ("Very much") NRS. Participants were asked the following question: "Think about all the areas of your skin with eczema. How much did your skin burn at its worst in the past 24 hours?" Lower score indicated better outcome.

Pruritus NRS was an assessment tool used to report the intensity of participant's pruritus (itch) during a daily recall period. Participants were asked to rate their worst itch on a 0 ("No itch") to 10 ("Worst itch imaginable") NRS by answering the following question: "On a scale of 0 to 10, with 0 being 'no itch' and 10 being the 'worst itch imaginable', how would you rate your itch at the worst moment during the previous 24 hours?". Higher scores indicated greater severity. Percentage of participants with change of >=4 point in pruritus NRS scale from baseline at Weeks 17 and 21 are reported in this outcome measure.