Schering sells ultrasound contrast agent in Europe

Schering has received marketing approval in three European countriesfor its Echovist ultrasound contrast agent.

The German pharmaceutical firm, first to enter the world marketwith an MRI contrast agent, received approval for Echovist inFrance and Italy late last year. Approval in Germany was grantedduring the second quarter of 1991, according to Rainer von Mielecki,a spokesman for Schering in Berlin.

Von Mielecki responded in writing to SCAN's questions regardingSchering's ultrasound contrast development program.

Initial approvals of Echovist are for use in ultrasound imagingof blood flow in the right side of the heart. Schering is preparingapplications for expanded indications of Echovist, to be submittedto the first national authorities late this year, he said.

Company researchers have used the agent for imaging flow inthe left side of the heart and in blood vessels, including verysmall vessels such as the coronary arteries and tumor vessels.Schering is also investigating a gynecological use of Echovistto diagnose Fallopian tube patency, he said.

Echovist, like other ultrasound agents under development, relieson air bubbles to scatter the ultrasound signal and create thecontrast effect. Schering uses a suspension of galactose microparticlesto convey the air bubbles, which are formed on the surface ofthe sugar crystals, von Mielecki said.

The galactose microparticles dissolve and the free galactoseis metabolized with a half-life of 11 minutes. These galactose-basedagents avoid allergic side-effects encountered with use of MolecularBiosystem's albumin microspheres, he said. The agents are contraindicatedin patients with a history of galactosemia, a genetic disease.

The German contrast firm is developing a second product on thesame galactose technology. Schering is planning to develop Levovist,a transpulmonary agent, for use in both the U.S. and Japan. Echovistis not under active development in the U.S., he said.

Schering's agents have a shelf life of three years, becausethe galactose microparticles are stored as dry material and mixedinto suspension immediately before use, he said.

Schering estimates the world market for ultrasound contrastagents will reach DM 1 billion ($595 million) by the year 2000.Because there are many more ultrasound scanners than MRI systemsaround the world, the market potential for ultrasound agents islarger than for MRI contrast products.

This difference is smaller in the U.S., however, because ofa relatively large number of installed MRI systems, von Mieleckisaid.