AcelRx, a biotech developing a Phase 3 treatment for acute post-operative pain, filed on Friday with the SEC to raise up to $86 million in an initial public offering. The Redwood City, CA-based company, which was founded in 2005 and has yet to generate product revenue, plans to list on the NASDAQ under the symbol ACRX. Piper Jaffray is the lead underwriter on the deal, for which pricing terms and timing were not disclosed.