Acusphere Announces Broad, Synthetic Polymer Microparticle Patent; Application of Delivery Technology to Cardiac Imaging With Ultrasound Contrast.

Business/Technology Editors & Health/Medical Writers

BOSTON--(BW HealthWire)--Oct. 31, 2000

Acusphere Inc. today announced the issuance of U.S. Patents 6,132,199 and 6,045,777 related to the company's intravenous delivery system for gas, which is being developed as an ultrasound contrast agent for the detection of coronary artery disease. U.S. Patent 6,132,199 broadly covers synthetic polymer compositions used to deliver any fluorinated gas, which is widely believed to be the best class of gases for ultrasound imaging. Acusphere is believed to be the only company with technology for delivering fluorinated gas with synthetic polymers. Acusphere has used synthetic polymers to overcome the limitations of earlier generation ultrasound contrast agents, which are made from natural materials such as albumin, sugars and lipids.

"Synthetic polymers have many compelling advantages as delivery systems over natural materials," said Robert S. Langer, Sc.D., the Kenneth Germeshausen Professor of Chemical and Biomedical Engineering at Massachusetts Institute of Technology, and Acusphere's scientific founder. "For instance, synthetic polymers are already manufactured at commercial scale, do not contain impurities or viruses, and most importantly, synthetic polymers can be engineered to obtain important product characteristics. As a result of these advantages, synthetic polymer drug delivery systems have been the major driver of the drug delivery field, and natural drug delivery systems have been limited to niche applications. Acusphere is taking the same principles that have been proven to be true in the drug delivery field and applying them to the ultrasound contrast field, where most of the development activity has focused on natural materials."

The technology described in U.S. Patent 6,045,777 is an example of how synthetic polymers can be used to engineer important product characteristics. Earlier generation ultrasound contrast agents, when injected in humans, create large shadows that block the region of interest from view. This shadowing occurs because these earlier agents attenuate (i.e. absorb) the ultrasound beam, rather than efficiently reflect the ultrasound. Acusphere scientists discovered that by engineering the thickness of the microparticle shell, this attenuation and shadowing phenomenon could be dramatically reduced. Engineering the shell thickness is extremely difficult with natural materials, but is straightforward with synthetic polymers. The patent defines the optimum shell thickness for minimizing shadowing and maximizing ultrasound reflection, and covers any gas-filled microparticle for ultrasound contrast imaging with a shell thickness in that optimum range.

With less shadowing, Acusphere's ultrasound contrast agent, AI-700, can provide clearer ultrasound images with the potential to improve sensitivity and specificity. In addition, AI-700 can be delivered as a simple, bolus injection, rather than by complex procedures required for earlier generation ultrasound agents to minimize their shadowing problem.

AI-700 is being developed initially for the detection of myocardial perfusion, or blood flow within the heart muscle. Myocardial perfusion assessment, used to detect ischemic heart disease (i.e. insufficient blood supply to the heart) , represents one of the largest potential applications for an intravenously delivered ultrasound contrast agent - over $1 billion worldwide. Myocardial perfusion cannot currently be assessed with standard ultrasound; instead patients are required to undergo nuclear medicine scans, which are significantly more expensive, time consuming, and expose the patient and medical staff to potentially damaging radiation.

Acusphere is a privately-held drug delivery company that is applying its porous microparticle technology to a number of novel delivery systems including intravenous delivery of gas and hydrophobic drug delivery (HDDS.) The company's lead product, AI-700, is an advanced ultrasound contrast agent that is in Phase 2 clinical trials. In preclinical development, Acusphere has Paclitaxel-HDDS, an improved formulation of Taxol(R), the $1.5 billion per year cancer drug. The company has raised $55 million to date from venture capital investors including Polaris Venture Partners, Burr, Egan, Deleage & Co., Thomas Weisel Partners , Bank of America Ventures, Prism Venture Partners, BancBoston Ventures, and New Medical Technologies.