Sienna Biopharmaceuticals Appoints Finance Veteran, James M. Hindman, to Board of Directors

-- Hindman will chair Sienna's Audit Committee

WESTLAKE VILLAGE, Calif., Aug. 02, 2018 (GLOBE NEWSWIRE) -- Sienna Biopharmaceuticals, Inc. SNNA, a clinical-stage medical dermatology and aesthetics company, today announced that James (Jim) M. Hindman has been appointed to the Company's Board of Directors. Mr. Hindman is the former chief financial officer and executive vice president, finance and business development of Allergan, Inc. and will join the Sienna Board of Directors immediately. Mr. Hindman will also chair the Company's Audit Committee.

"Jim's appointment to the Board supports Sienna's ambition to rapidly progress multiple clinical development programs across several therapeutic indications where innovation is still greatly needed," said Keith R. Leonard Jr., Chairman of Sienna's Board of Directors. "Jim is an accomplished financial leader who helped build one of the most successful healthcare companies in the world. He is highly regarded by investors for his track record of success and will provide invaluable guidance to Frederick and Sienna's executive team as they continue to build out their operational strengths."

David E.I. Pyott, former Chairman of the Board and Chief Executive Officer of Allergan, Inc., and Strategic Advisor to the Sienna Board and Chief Executive Officer, said, "As head of investor relations, risk and treasury, and ultimately as chief financial officer of Allergan, Jim was instrumental during a period of remarkable growth and transformation from a small cap eye care company to a global multi-specialty pharmaceutical leader. His passion for improving patients' lives, combined with his financial and business acumen, made him a highly trusted ambassador of Allergan's mission for several decades."

Mr. Hindman brings more than 30 years of experience leading and working with diverse global businesses in the pharmaceutical, biologics and medical device industries, serving most recently as chief financial officer and executive vice president, finance and business development at Allergan. Prior to that, he was senior vice president, treasury, risk and investor relations, and previously served in a variety of finance positions, including senior vice president, finance, vice president financial planning and analysis, and assistant corporate controller. Mr. Hindman serves as a member of the board of regents at Loyola Marymount University, and from 2007 to 2015 he served on its accounting advisory board. He also serves as a board member at Millendo Therapeutics, Inc. From 2009 to 2015, he served as a member of the board of directors of The Allergan Foundation. Mr. Hindman earned a B.S. in accounting from Loyola Marymount University and an M.B.A. from Pepperdine University, and is a Certified Public Accountant (inactive).

Sienna also announced that Erle Mast has decided to step down from the Company's Board for personal reasons.

"We are very thankful to Erle for his service to the Company. He has been invaluable in guiding Sienna through the IPO process and our first year as a public company," said Frederick C. Beddingfield III, MD, PhD, President and Chief Executive Officer of Sienna. "His insights and counsel have been important in helping us cement our corporate strategy and finance our unique and robust pipeline of multiple technology platforms."

About Sienna Biopharmaceuticals

Sienna Biopharmaceuticals, Inc. is a clinical-stage biopharmaceutical company focused on bringing innovations in biotechnology to the discovery, development and commercialization of first-in-class, targeted, topical products in medical dermatology and aesthetics. The Company's objective is to develop a unique, diversified, multi-asset pipeline of topical therapies that enhance the health, appearance and quality of life of dermatology and aesthetics patients. Sienna is led by a management team with extensive experience in product development and commercialization at several leading dermatology, aesthetics and biotechnology companies.

For more information, visit the Company's website at www.SiennaBio.com.

Forward-Looking Statements

This press release contains forward-looking statements, including but not limited to statements by Sienna's Chairman of the Board, Chief Executive Officer and Strategic Advisor and other statements regarding the appointment of James M. Hindman to Sienna's Board of Directors. Such forward-looking statements involve substantial risks and uncertainties that could cause Sienna's clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the pharmaceutical drug and medical device development processes, including regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing pharmaceutical drug and medical device products, Sienna's ability to successfully protect and defend its intellectual property, and other matters that could affect the sufficiency of existing cash to fund operations and the availability or commercial potential of Sienna's drug candidates. Sienna undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the Company in general, see Sienna's most recent Annual Report on Form 10-K and any subsequent current and periodic reports filed with the Securities and Exchange Commission.

Contact:

Media
Caroline Van Hove
cvanhove@siennabio.com
818-575-6250

Crystal Muilenburg
cmuilenburg@siennabio.com
818-584-1035

Investors
Sean Andrews
sandrews@siennabio.com
818-629-2244