Sienna Biopharmaceuticals has retained Cowen as an independent financial advisor to explore “financial and strategic alternatives” to boost shareholder values, the company announced Monday. The Westlake Village research biotech will continue to raise capital to initiate phase 3 clinical trials for its psoriasis topical cream, but the company will not start the trials until the necessary capital is secured. According to a statement from the company, no specific financial or strategic path has been chosen yet. The company went public in 2017. Shares of Sienna Biopharmaceuticals (SNNA) closed Monday down 4 cents, or 4.9 percent, to 79 cents on the Nasdaq.