Sienna Biopharmaceuticals, Inc., a clinical-stage biopharmaceutical company, focuses on the development of drugs in various therapeutic areas. It develops therapies in immunology and inflammation that target select pathways in tissues, such as skin. The company's lead product candidates include SNA-120, a first-in-class inhibitor of tropomyosin receptor kinase A, which is in a Phase IIb clinical trial for the treatment of psoriasis and associated pruritus; and SNA-125, a topical dual Janus kinase 3 inhibitor that is in Phase I/II clinical trials for the treatment of atopic dermatitis, psoriasis, and pruritus. It also develops SNA-001, a topical suspension of silver particles, which is in pivotal clinical trials for the treatment of acne, as well as for the reduction of light-pigmented hair, including white, gray, blonde, light brown, and light red hair. The company was formerly known as Sienna Labs, Inc. and changed its name to Sienna Biopharmaceuticals, Inc. in February 2016. Sienna Biopharmaceuticals, Inc. was founded in 2010 and is headquartered in Westlake Village, California. On September 16, 2019, Sienna Biopharmaceuticals, Inc. filed a voluntary petition for reorganization under Chapter 11 in the U.S. Bankruptcy Court for the District of Delaware.