This is a double-blind, randomized, vehicle-controlled, multi-center, parallel group Phase 3 study of MSRD-100 in the treatment of atopic dermatitis in subjects aged 3 months and up.

This is a 4-week efficacy, safety and tolerability study of MSRD-100 applied twice daily for 4 weeks compared to its vehicle among subjects ≥3 months of age in the treatment of atopic dermatitis covering ≥5% body surface area.

The study will consist of up to 4 visits which includes Screening - Visit 1 (Screening), Baseline - Visit 2 , Visit 3 (Day 14), and an End of Treatment/Final Study Visit - Visit 4 (Day 28).

Study IDs M169981001 and M169981002 are two identical studies being run in parallel with different study sites.

Key Inclusion Criteria:

1. Subjects who are male or female, ≥3 months of age on the date of Baseline Visit.
2. Subjects with a diagnosis of atopic dermatitis, active inflammation and meeting the Hanifin and Rajka Diagnosis Criteria for Atopic Dermatitis.
3. Subjects must have an Investigator Global Assessment (IGA) score of ≥2 at baseline.
4. Subjects who have atopic dermatitis covering ≥5% Body Surface Area (BSA) excluding the eyelids, perioral area, around the nostrils, and in the diaper area (for subjects who wear diapers or plastic pants).
5. Subjects who have atopic dermatitis with a sign and symptom score ≥ 2 on the following three signs and symptoms: erythema, infiltration/papulation, and erosion/oozing/crusting present in at least one body surface area affected.

Key Exclusion Criteria:

1. Unstable course of Atopic Dermatitis (spontaneously improving or rapidly deteriorating) as determined by the investigator over the previous 4 weeks prior to baseline.
2. Concurrent conditions and history of other diseases.
3. Used any of the following treatments within the indicated washout period before the baseline visit or those who would require the following during the study.
4. Subjects who require treatment with any other topical or systemic therapy for the study disease other than bland emollients in untreated areas of disease.