Sienna Biopharmaceuticals Appoints Erle Mast, Former CFO and Co-Founder of Clovis Oncology, to Board

Sienna Biopharmaceuticals, Inc., a privately held, 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, today announced that Erle Mast has been appointed to Sienna’s Board of Directors. Mr. Mast will chair the Audit Committee.

"We are pleased to announce Erle’s appointment to the Sienna Board," said Keith R. Leonard Jr., Chairman of Sienna’s Board of Directors. "He brings more than 30 years of experience in corporate finance, biopharmaceutical operations and public-company executive leadership. He has taken two start-up companies public, one of which he helped co-found, and then helped to grow both of them into multi-billion dollar companies. We believe Erle’s extensive experience and seasoned judgment will be a critical addition to Sienna’s Board as we build this enterprise."

"I am excited to join the board of such a well-managed company at the forefront of innovation in topical dermatology," said Mr. Mast. "Sienna’s pipeline has the potential to address the unmet needs of a remarkably large patient population burdened by skin conditions that negatively impact confidence and daily life. I look forward to collaborating with my fellow directors and this fine management team as we work toward exciting times ahead."