Acusphere Receives Second U.S. Patent for the Use of Sustained Release Porous Microparticle Formulations.

Business Editors/Health/Medical Writers

WATERTOWN, Mass.--(BUSINESS WIRE)--Feb. 11, 2004

Acusphere, Inc. (NASDAQ: ACUS), a specialty pharmaceutical company that develops drugs using its porous microparticle technology, announced today the issuance of U.S. Patent 6,689,390 entitled "Matrices Formed of Polymer and Hydrophobic Compounds for Use in Drug Delivery."

The patent relates to the use of certain porous microparticle formulations using slowly dissolving shell materials to create sustained release formulations of a variety of drugs, particularly hydrophobic drugs, which are drugs that do not dissolve well in water. It is difficult to create sustained release formulations for many hydrophobic drugs because they release too slowly from the microparticles used to deliver the drug. Modifying the water uptake into the microparticles can speed the release, while retaining the desired sustained release profile of these drugs. Acusphere's technology modifies water uptake into microparticles by adjusting the porosity of the microparticles during manufacture and by choosing from a wide variety of materials to include in the microparticle's shell. This is Acusphere's second issued patent related to this sustained release technology; the first issued patent relates to compositions created by the technology.

"Acusphere's technology has the potential to develop sustained release formulations of hydrophobic drugs for a variety of routes of administration," commented Sherri C. Oberg, President and CEO of Acusphere. "We have clinical trial data that we believe demonstrates human proof-of-concept of the ability to administer sustained release formulations of a hydrophobic drug for inhalation. And, importantly, we believe there is also significant potential to create sustained release formulations for oral and injectable delivery, which are other leading methods of drug administration today. We believe that sustained release technology for hydrophobic drugs is an under-served area for which very limited options exist."

Acusphere estimates that hydrophobic drugs generated more than $100 billion in revenue in 2000 and constituted up to 40% of all drugs in development. Many hydrophobic drugs must be administered multiple times each day over a long period of time, causing patient discomfort and inconvenience, requiring medical staff attention and increasing costs. The creation of sustained release formulations of these drugs could improve patient compliance, and thereby the efficacy of these drugs.

Acusphere's porous microparticle technology has the potential to create sustained release formulations of these difficult to formulate hydrophobic drugs. Our porous microparticle formulations have tightly controlled size distributions, and have the potential to release drugs over periods ranging from days to weeks by intravenous, inhalation, subcutaneous or oral routes of administration. Acusphere is currently using this technology to develop AI-128, a sustained release formulation of a hydrophobic asthma drug. AI-128 is designed to slowly release the drug locally into the lungs, thereby potentially reducing the multi-dosing per day regimen to a longer-lasting, once per day regimen.

About Acusphere, Inc.

Acusphere 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 in clinical development and are designed to address large unmet clinical needs within cardiology, oncology and asthma. These product candidates were created using proprietary technology that enables Acusphere to control the porosity and size of nanoparticles and microparticles in a versatile manner that allows particles to be customized to address the delivery needs of a variety of drugs. Acusphere's lead product candidate, AI-700, is a cardiovascular drug in Phase III clinical development. AI-700 is designed to be a preferred alternative to the estimated 9.5 million procedures done each year in the U.S. to detect coronary artery disease, the leading cause of death in the United States. For more information about Acusphere visit the Company's web site at www.acusphere.com.

"Acusphere" is a trademark of Acusphere, Inc.

This Release contains forward-looking statements, including statements regarding Acusphere's ability to develop improved formulations of hydrophobic drugs. The Company's actual results may differ materially from those anticipated in these forward-looking statements based upon a number of factors, including anticipated operating losses, uncertainties associated with research, development, testing and related regulatory approvals, unproven markets, future capital needs and uncertainty of additional financing, competition, uncertainties associated with intellectual property, complex manufacturing, high quality requirements, dependence on third-party manufacturers, suppliers and collaborators, lack of sales and marketing experience, loss of key personnel, uncertainties associated with market acceptance and adequacy of reimbursement, technological change and government regulation, and other risks and challenges detailed in the Company's filings with the U.S. Securities and Exchange Commission. Readers are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date of this Release. The Company undertakes no obligation to publicly release the results of any revisions to these forward-looking statements that may be made to reflect events or circumstances that occur after the date of this Release or to reflect the occurrence of unanticipated events.