Acusphere, Inc. Receives U.S. Patent for Helping Taxanes Dissolve Rapidly.

Business Editors/Health/Medical Writers

WATERTOWN, Mass.--(BUSINESS WIRE)--Aug. 27, 2003

Acusphere, Inc., a specialty pharmaceutical company that develops new drugs and improves formulations of existing drugs using its porous microparticle technology, announced today the issuance of U.S. Patent 6,610,317 entitled " Porous Paclitaxel Matrices and Methods of Manufacture Thereof." The patent claims compositions of porous matrices containing taxanes with improved dissolution rates and the methods of producing such porous matrices. Taxanes are a class of drug used in leading cancer treatments. Taxanes are generally hydrophobic (they have difficulty dissolving in water). Because the human body is primarily composed of water, drugs that cannot be readily dissolved can be limited in their effectiveness.

Acusphere's technology works by encapsulating very small drug particles in a matrix, which upon contact with water, dissolves immediately leaving a suspension of the drug particles to rapidly dissolve upon further dilution. The size of the matrix encapsulating these drug particles is typically smaller than a red blood cell. In creating a suspension of very small drug particles, the relative surface area of each particle is increased promoting more rapid dissolution. Acusphere refers to this technology as its Hydrophobic Drug Delivery System (HDDS(TM)).

Many drugs are hydrophobic. The first product candidate using Acusphere's HDDS technology is AI-850, a rapidly dissolving formulation of paclitaxel, the active ingredient in the cancer drug, Taxol. By using HDDS, Acusphere has created sponge-like microparticles of paclitaxel without the use of Cremophor, an oil used in Taxol that is believed to cause severe hypersensitivity reactions. AI-850 doses currently being evaluated in patients in a Phase I clinical study are higher than the doses of paclitaxel customarily delivered using the same dosing schedule of Taxol for the treatment of metastatic breast cancer. Acusphere has shown that its HDDS technology improves the dissolution rate of a variety of orally and intravenously administered hydrophobic drugs and is evaluating the application of its HDDS technology in various product candidates beyond AI-850.

"We are pleased that this new patent has issued covering important aspects of our HDDS technology and its application in AI-850," said Sherri C. Oberg, President and Chief Executive Officer. "This is our twelfth issued U.S. patent related to our microparticle technology."

About Acusphere, Inc.

Acusphere is a privately held specialty pharmaceutical company that develops new drugs and improved formulations of existing drugs using its proprietary microparticle technology. Drugs being developed by Acusphere are intended to offer significant benefits such as improved safety and efficacy, increased patient compliance, greater ease of use, expanded indications or reduced cost. 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 size and porosity of microparticles in a versatile manner which allows microparticles to be customized to address the delivery needs of a variety of drugs. They each were created using porous microparticles that are smaller than red blood cells. Acusphere's lead product candidate, AI-700, is a cardiovascular drug in Phase III clinical development for the detection of coronary artery disease, the leading cause of death in the United States. For more information about Acusphere visit the company's web site at http://www.acusphere.com.