Phase 2a Study of the Safety, Tolerability, and Pharmacokinetics of Topically Administered PRN473 (SAR444727) in Patients With Mild to Moderate Atopic Dermatitis

This was a Ph2a study that consists of a double-blind, intra-patient placebo-controlled treatment period and an open-label uncontrolled treatment period with objective to evaluate the safety, tolerability, PK and preliminary efficacy of PRN473 in up to 40 patients with mild to moderate AD.

On Day 1 (Baseline) of the Blinded Period, 2 target lesions with a difference no greater than 1 point in Total Sign Score (TSS) were randomly assigned to treatment in an intra-patient 1:1 manner, one lesion to PRN473 and the other to matching placebo.

Participation took approximately 13 weeks, including up to a 5-week screening period, a 6-week treatment period, end of study assessments 1 day after last dose, and a safety follow-up phone call 2 weeks after last dose.

Study duration per patient was approximately 56 days including a 42-days treatment period.

Eligibility Criteria:
Inclusion Criteria:

* Male and female adults 18 to 70 years of age (inclusive) at the time of informed consent.
* Diagnosed with mild to moderate AD.
* History of AD for at least 6 months as determined by the Investigator through patient interview.
* Stable disease for the 4 weeks prior to the screening visit with no significant flares in AD as determined by the Investigator.
* Validated Investigator Global Assessment-atopic dermatitis (vIGA-AD) score of Moderate or Mild at Screening. The vIGA-AD was evaluated for the entire body except scalp, palms, soles and genitals.
* HadAD involvement (excluding scalp, palms, soles and genitals) of at least 1.0% BSA and no more than 14.0% BSA.
* Had at least two target lesions 100 cm2 or greater with a difference no greater than 1 point in lesion TSS and at least 5 cm apart located on the trunk (excluding genitals) or upper extremities (excluding palms).
* If female, patients with child-bearing potential must have a negative pregnancy test, and agree to practice true abstinence or agree to use highly effective contraception.
* If male, agree to use a male condom and highly effective contraception with female partners of child-bearing potential.
* In good health as judged by the Investigator.

Exclusion Criteria:

* Patients who had failed 2 or more prior systemic treatments for AD.
* Patients who had received a live or attenuated vaccine in the last 12 weeks or intend to receive a live or attenuated vaccine during the study.
* Patients who cannot discontinue prohibited medications and treatments prior to the Baseline visit and during the study.
* Has unstable AD, based on the judgement of the Investigator, or any consistent requirement for high potency topical steroids to manage AD signs or symptoms.
* Patients who had significant active systemic or localized bacterial, viral, fungal, and helminth infection in the last 30 days.
* Patients unwilling to refrain from prolonged sun exposure or use of a tanning bed or other artificial light emitting devices for 4 weeks prior to Baseline and during the study.
* Patients with other skin conditions that would interfere with evaluations of the effect of the study medication on AD, as determined by the Investigator.
* Patients with known genetic dermatological conditions that overlap with AD, such as Netherton syndrome.
* Previous used of a BTK inhibitor.
* Women who were pregnant, wishing to become pregnant during the study, or were breastfeeding.
* Patients were undergoing allergy (eg, food allergy testing or skin prick testing), patch testing, or food challenges, or plan to do so during the study.
* Patients who had undergone major surgery within 4 weeks prior to Day 1 or patients who had a major surgery planned during the study.
* Regular use of drugs of abuse or regular alcohol consumption within 6 months prior to the study.