Acusphere Announces Key Patent Issuance.

BOSTON--(BW HealthWire)--Nov. 17, 1998--

Growing Patent Portfolio Covers Advanced Contrast Agents for

Enhancing Ultrasound Images

Acusphere, Inc. today announced the issuance of a key patent by the U.S. Patent and Trademark Office relating to the company's technology for producing third-generation ultrasound contrast agents. The patent, US 5,837,221, describes materials and methods for making highly echogenic (sound-responsive) gas-filled microspheres for use in ultrasound imaging. The company also announced the issuance of U.S. Patent 5,611,344 covering microspheres made of synthetic polymers containing perfluorocarbon gases. Acusphere now holds or has exclusive rights to 11 issued patents and 30 patent applications.

"These are important patents in the emerging field of ultrasound contrast agents," said Sherri Oberg, Acusphere president and chief executive officer. "They establish the company as the technology leader in the development of advanced ultrasound contrast agents. Acusphere's proprietary synthetic polymer technology has the potential to move the ultrasound contrast field into important new applications, such as myocardial perfusion, where first- and second-generation agents have not been able to demonstrate the sensitivity and specificity required to displace the current standard of care - nuclear medicine."

The newly patented technology has enabled Acusphere to solve one of the key problems facing commercially-available ultrasound agents: gas leakage. The effectiveness of an ultrasound contrast agent is related to the amount of gas inside the microparticle. Commercially-available ultrasound contrast agents, when injected into blood, leak gas, minimizing their effectiveness. Acusphere scientists discovered that certain water-repellent substances, when integrated into the polymer shell, limit the penetration of water into the microsphere and the subsequent displacement of the gas. By retaining the gas inside the microcapsule, the diagnostic signal is strengthened and prolonged. The patent broadly covers any synthetic or natural polymer, any gas and broad classes of water-repellent materials used with a wide variety of microencapsulation processes for ultrasound imaging.

U.S. Patent 5,611,344 was issued to Acusphere last year covering compositions made with synthetic polymers and perfluorocarbon gases for ultrasound imaging. Synthetic polymers have high mechanical strength, which is also important for retaining gas inside the microcapsule. Fragile microspheres release gas when broken, rendering them ineffective as contrast agents. Commercially-available ultrasound contrast agents are made with natural materials which are so fragile that they break down under the ultrasound power settings that are often necessary to get good myocardial perfusion enhancement with standard ultrasound imaging techniques. Acusphere's lead product, AI-700, does not break under any ultrasound power setting used clinically.

Acusphere's lead product, AI-700, is a gas-filled synthetic polymer microsphere being developed initially for the detection of myocardial perfusion, or blood flow within the heart muscle. Myocardial perfusion assessment, used to identify damage from heart disease and diagnose heart attacks, represents one of the largest potential applications for an intravenously-delivered ultrasound agent -- over $1 billion worldwide. Because of technical limitations, myocardial perfusion cannot currently be assessed with standard echocardiography; instead patients are required to undergo nuclear medicine scans, which are significantly more expensive.

Acusphere, a privately-held company, is developing the first ultrasound contrast agent with broad cardiac imaging capabilities using standard ultrasound imaging techniques. The company's lead product, AI-700, is expected to enter Phase I human clinical trials in early 1999. Acusphere has 38 employees and has raised over $25 million to date from venture capital investors including Burr, Egan, Deleage & Co., BankAmerica Ventures, Prism Ventures, Polaris Ventures, BancBoston Ventures, Technology Funding, The CIT Group, Boston University and The Venture Capital Fund of New England.