vIGA-AD measures participants' overall severity of their atopic dermatitis (AD), based on a static, numeric 5 point scale from 0 (clear) to 4 (severe). Higher scores indicate greater severity.The score is based on an overall assessment of the degree of erythema, papulation/induration, oozing/crusting, and lichenification. Non-responder imputation (NRI) method was used to impute missing data.

Induction Period: All randomized participants who completed or discontinued the study prior to study termination by the sponsor.

EASI assesses objective physician estimates of 2 dimensions of atopic dermatitis - disease extent and clinical signs - by scoring the extent of disease (percentage of skin affected: 0 = 0%; 1 = 1-9%; 2 = 10-29%; 3 = 30-49%; 4 = 50-69%; 5 = 70-89%; 6 = 90-100%) and the severity of 4 clinical signs (erythema, edema/papulation, excoriation, and lichenification) each on a scale of 0 to 3 (0 = none, absent; 1 = mild; 2 = moderate; 3 = severe) at 4 body sites (head and neck, trunk, upper limbs, and lower limbs). Half scores are allowed. Each body site will have a score that ranges from 0 to 72, and the final EASI score will be obtained by weight-averaging these 4 scores. Hence, the final EASI score will range from 0 to 72 (severe) for each time point. A higher score represented greater disease severity.The EASI75 is defined as a ≥ 75% improvement from baseline in the EASI score. Non-responder imputation (NRI) method was used to impute missing data.

Induction Period: All randomized participants who completed or discontinued the study prior to study termination by the sponsor.

The SCORAD index uses the rule of nines to assess disease extent (head and neck 9%; upper limbs 9% each; lower limbs 18% each; anterior trunk 18%; back 18%; and genitals 1%). It evaluates 6 clinical characteristics to determine disease severity: (1) erythema, (2) edema/papulation, (3) oozing/crusts, (4) excoriation, (5) lichenification, and (6) dryness on a scale of 0 to 3 (0=absence, 1=mild, 2=moderate, 3=severe). The SCORAD index also assesses subjective symptoms of pruritus and sleep loss in the last 72 hours on visual analogue scales (VAS) of 0 to 10 where 0 is no itch or sleep loss and 10 is worst imaginable itch or sleep loss. These 3 aspects: extent of disease, disease severity, and subjective symptoms combine to give a score between 0(no disease) and 103 (severe disease). Higher scores indicate greater severity.Non-responder imputation (NRI) method was used to impute missing data.

Induction Period: All randomized participants who completed or discontinued the study prior to study termination by the sponsor.

vIGA-AD measures participants overall severity of their atopic dermatitis (AD), based on a static, numeric 5 point scale from 0 (clear) to 4 (severe). Higher scores indicate greater severity. The score is based on an overall assessment of the degree of erythema, papulation/induration, oozing/crusting, and lichenification. Non-responder imputation (NRI) method was used to impute missing data.

Induction Period: All randomized participants who completed or discontinued the study prior to study termination by the sponsor.

EASI assesses objective physician estimates of 2 dimensions of atopic dermatitis-disease extent and clinical signs-by scoring the extent of disease(percentage of skin affected: 0= 0%;1 =1-9%; 2 =10-29%;3 = 30-49%;4 = 50-69%;5 = 70-89%;6 = 90-100%) and the severity of 4 clinical signs (erythema,edema/papulation,excoriation,and lichenification) each on a scale of 0 to 3 (0 = none, absent; 1 =mild; 2 = moderate; 3=severe) at 4 body sites(head and neck,trunk,upper limbs,and lower limbs).Half scores are allowed.Each body site will have a score that ranges from 0 to 72,and the final EASI score will be obtained by weight-averaging these 4 scores.Hence,the final EASI score will range from 0 to 72(severe) for each time point.Higher scores indicate greater severity.Least Squares Mean(LS Means) were calculated using mixed model repeated measures(MMRM) with treatment,region, baseline disease severity,visit,treatment-by-visit-interaction,baseline and baseline-by-visit-interaction as fixed effects.

Induction Period: All randomized participants who had a baseline and at least one post-baseline EASI value.

The SCORAD index uses the rule of nines to assess disease extent (head and neck 9%;upper limbs 9% each;lower limbs 18% each;anterior trunk 18%;back 18%;and genitals 1%).It evaluates 6 clinical characteristics to determine disease severity: (1)erythema,(2)edema/papulation, (3)oozing/crusts,(4) excoriation,(5) lichenification, and (6) dryness on a scale of 0 to 3(0=absence,1=mild,2=moderate,3=severe).The SCORAD index also assesses subjective symptoms of pruritus and sleep loss in the last 72 hours on visual analogue scales(VAS) of 0 to 10 where 0 is no itch or sleep loss and 10 is worst imaginable itch or sleep loss.These 3 aspects: extent of disease,disease severity,and subjective symptoms combine to give a score between 0(no disease) and 103(severe disease).Higher scores indicate greater severity. LS Means were calculated using a MMRM model with treatment,region,baseline disease severity,visit, treatment-by-visit-interaction,baseline and baseline-by-visit-interaction as fixed effects.

Induction Period: All randomized participants who had a baseline and at least one post-baseline SCORAD value.

vIGA-AD measures participants overall severity of their atopic dermatitis (AD), based on a static, numeric 5 point scale from 0 (clear) to 4 (severe). Higher scores indicate greater severity. The score is based on an overall assessment of the degree of erythema, papulation/induration, oozing/crusting, and lichenification. Non-responder imputation (NRI) method was used to impute missing data.

Maintenance Period: All randomized participants who had a >=2-point improvement at Week 52.

Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve at a steady state (AUCτ,ss) of LY3375880. The PK model was fit using all quantifiable concentrations that were collected in the study (i.e., from the induction and maintenance periods).

All randomized participants who received LY3375880 in induction and maintenance period who had evaluable PK data. Participants did not received 300 mg because the trial was stopped early.