Adverum Biotechnologies Inc., of Menlo Park, Calif., priced its public offering of about 8.9 million shares at $6.75 per share for gross proceeds of about $60 million. The gene therapy company granted underwriters a 30-day option to purchase up to an additional 1.3 million shares. Cowen and Piper Jaffray & Co. are acting as joint book-running managers, while Raymond James & Associates Inc. is acting as lead manager for the offering, set to close on or about Feb. 9. Shares of Adverum (NASDAQ:ADVM) closed Thursday at $7.50, up 40 cents.