Sienna Biopharmaceuticals Inc., a Westlake-Village biotech working on novel laser hair removal and skin therapies, announced Friday the appointment of Chief Financial Officer Richard Peterson, effective immediately. Peterson replaces John Smither, who is retiring at the end of April but will continue in an advisory role. Smither was also chief financial officer at Kythera Biopharmaceuticals Inc. before it was acquired by drug giant Allergan for $2.1 billion in 2015. From there, the former management team went on to start Sienna. Peterson joins the company from dermatology drug developer Novan Inc. of Morrisville, N.C., where he also served as top financial executive. Before that he held the same position at Scottsdale, Ariz. medical cosmetics company Medicis Pharmaceutical Corp. before its 2012 acquisition for $2.6 billion by Canada-based Valeant Pharmaceuticals International Inc. “We are pleased to welcome Ric to Sienna and look forward to his contributions as we advance our robust and diversified pipeline of topical biotech products,” Chief Executive Dr. Frederick Beddingfield III said in a statement. “Ric is an accomplished financial leader with a proven track record of creating value for medical dermatology and aesthetic companies that develop and market industry-leading products.”