Sienna Biopharmaceuticals, a privately held, clinical stage medical dermatology and aesthetics company, today announced that it completed a $40 million Series B financing led by existing investors ARCH Venture Partners and Venvest Capital. Additional investors participating included Partner Fund Management, Altitude Life Science Ventures, and Dr. David Pyott. New investors accounted for approximately half of the investments and included Fidelity Management & Research Company, certain investment funds advised by Clough Capital Partners L.P., Omega Fund Management, and others.

Sienna's mission is to develop safe and effective targeted therapies to treat inflammatory skin conditions and aesthetic problems that impact the health, appearance, and quality of life of patients.

Sienna intends to use the proceeds from this financing to advance its diversified topical biotech pipeline. Through its Topical by DesignTM platform, Sienna is developing its lead assets, SNA-120 (TrkA inhibitor) for pruritus and psoriasis (Phase IIb) and SNA-125 (dual TrkA/JAK3 inhibitor) for atopic dermatitis, psoriasis and pruritus (proof-of-concept). Through its photoparticle therapy platform, Sienna is developing SNA-001 for the treatment of acne vulgaris (pivotal trials) and for the permanent reduction of unwanted light-pigmented hair (pivotal trials).

"We are very pleased with the support of investors who share our commitment to developing innovative and disruptive new products in medical dermatology and aesthetics," said Frederick C. Beddingfield III, MD, PhD, Sienna's President and Chief Executive Officer. "We have built out an accomplished team and a diversified multi-asset pipeline. We believe this financing will enable us to advance our development programs, which span pivotal clinical trials to preclinical programs."

About Sienna Biopharmaceuticals
Sienna Biopharmaceuticals, Inc., is a medical dermatology and aesthetics company focused on developing safe and effective targeted therapies to treat inflammatory skin conditions and aesthetic concerns that impact the health and appearance of patients. Sienna is led by a team of accomplished scientists, clinicians and business leaders who have developed and commercialized leading global brands in dermatology and aesthetics. Sienna is building an innovative, diversified pipeline to address unmet needs in medical dermatology and aesthetics. The company's investors include: ARCH Venture Partners; Partner Fund Management; Fidelity Management & Research Company Venvest Capital; Sofinnova Capital V; Altitude Life Science Ventures; Two River; certain investment funds advised by Clough Capital Partners L.P.; Omega Fund Management; and NeoMed IV. Find more information at www.siennabio.com.