Evaluation of Topical ATR12-351 in Adults With Netherton Syndrome

The objectives of this clinical trial are to evaluate the safety and tolerability of topically applied ATR12-351, to understand what the body does to ATR12-351, and to observe treatment benefits of the drug in approximately 12 adult patients with Netherton Syndrome (NS). ATR12-351 will be applied to skin lesions on one side of the body, while the vehicle control will be applied to similar lesion on the other side of the body twice daily for 2 weeks.

Inclusion Criteria: * Adults ≥18 years of age * Confirmed mutation of the serine protease inhibitor of Kazal type 5 (SPINK5) gene * Involvement of ≥20% of body surface area with skin changes consistent with Netherton syndrome Exclusion Criteria: * Use of biologic therapies, antibiotics, antihistamines, corticosteroids, retinoids, disease-modifying antirheumatic drugs (DMARDs), immunosuppressive agents, phosphodiesterase-4 (PDE4) inhibitors, topical calcineurin inhibitors, or topical Janus kinase (JAK) inhibitors * Open wounds or extensive areas of excoriation precluding identification of appropriate application sites in the Investigator's judgment * Concurrent involvement in any other clinical study/expanded access program with an investigational drug or device or has participated in a clinical study within 30 days prior to the screening visit * Residing with an immunocompromised person in the same dwelling from the baseline visit through 2 weeks after the treatment period * History of ultraviolet phototherapy within the planned treatment area 4 weeks prior to baseline