News Release

Yamanouchi Pharmaceutical Co., Ltd.

Yamanouchi begins clinical development of ultrasound contrast agent

June 25,1998

Yamanouchi Pharmaceutical Co., Ltd. (president and CEO: Masayoshi Onoda), will begin work on the Japanese clinical development of a new ultrasound contrast agent designated YM454. The contrast medium was created by ImaRx Pharmaceutical Corp., in Tucson, Arizona, and is being developed under license by Yamanouchi. The licensing agreement gives Yamanouchi marketing rights for Asia, including Japan.

Ultrasound imaging offers advantages over other imaging modalities, including computed tomography and magnetic resonance imaging, in that the equipment required is less expensive and specialized examination rooms are not necessary. For these reasons, and because image diagnosis is possible in real time, the use of ultrasound imaging for medical diagnosis is a rapidly expanding field. On the other hand, the weak points of ultrasound include the fact that images are sometimes affected by patients' anatomical characteristics, such as obesity or gas in the digestive tact, and that diagnostic capabilities depend on the experience of the examiner, so that it is somewhat lacking in objectivity. The use of a contrast agent improves the quality of ultrasound images and enhances the diagnostic capabilities, suggesting the potential for the use of ultrasound images in diagnosis.

Furthermore, a contrast agent enables the imaging of blood perfusion information, and thus allows such cardiac conditions as infarctions or angina to be diagnosed quantitatively with images. This method of diagnosis is expected to gradually take the place of the nuclear medicine techniques, a golden standard in this area.

YM454 consists of lipid-coated microbubbles of perfluorocarbon gas. These bubbles are smaller than red blood cells, and when introduced intravenously they render the bloodstream visible. YM454 represents significant improvements over earlier ultrasound contrast mediums in terms of particle size, distribution, and stability in the bloodstream. In Europe and the US, the development of the new contrast medium has been conducted by ImaRx's licensee, DuPont Pharmaceutical Company, under the product development number DMP115, and plans call for an application for approval in the near future.

ImaRx Pharmaceutical Corp.

Established:December 1990

Head office: Tucson, Arizona

CEO and President: Evan C. Unger, M.D.

Main business: Design and development of products for medical imaging (magnetic resonance, ultrasound, and computed tomography) as well as innovative technologies for therapeutic drug and gene delivery