Exhibit 99.1
FOR IMMEDIATE RELEASE
Acusphere Announces Pricing of Common Stock Offering
WATERTOWN, MA, September 23, 2005 — Acusphere, Inc. (NASDAQ: ACUS), today announced that on September 22, 2005 it priced an offering by it of 3,566,000 shares of its common stock at a purchase price of $5.25 per share, for estimated net proceeds of approximately $17.5 million, after deducting fees and commissions and estimated offering expenses. Piper Jaffray & Co. is acting as sole underwriter for the offering.
A shelf registration statement relating to the shares that Acusphere intends to sell has previously been filed with, and has been declared effective by, the Securities and Exchange Commission. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction. Any offer will be made only by means of a prospectus, including a prospectus supplement, forming a part of the effective registration statement. Copies of the final prospectus supplement together with the accompanying prospectus can be obtained from Piper Jaffray & Co. at 800 Nicollet Mall, Suite 800, Minneapolis, MN 55402, (612) 303-6000.
About Acusphere, Inc.
Acusphere (NASDAQ:ACUS) is a specialty pharmaceutical company that develops new drugs and improved formulations of existing drugs using its proprietary microparticle technology. Acusphere’s three initial product candidates are designed to address large unmet clinical needs within cardiology, oncology and asthma.
