Medstone Submits PMA For Non-Invasive Gallstone Treatment.

ALISO VIEJO, Calif.--(BW HealthWire)--Sept. 4, 1997--Medstone International Inc. (NASDAQ:MEDS) Thursday announced that it has submitted an application for a pre-market approval (PMA) with the U.S. Food & Drug Administration (FDA) to treat gallstones using the company's non-invasive lithotripter in conjunction with Actigall (ursodiol USP), a gallstone dissolution medication from Novartis Pharmaceuticals Corp. (East Hanover, N.J.).

The submission is based on an analysis of clinical trials for Actigall monotherapy and separate clinical trials for combination therapy with lithotripter and Actigall. An analysis of these separate trials indicates that the combination therapy of a device and drug can speed up clearance of the gallstones and result in higher success rates when compared to drug therapy alone.

"Should the Medstone STS be approved to treat gallstones, it will be the only lithotripter approved in the United States to treat both renal stones and gallstones on the same equipment," said David Radlinski, Medstone chairman and chief executive officer. "This means a higher utilization of the Medstone machines already in the field and a comparative advantage in the competition for new sales."

An estimated 20 million Americans have gallstones of which 2.3 million are symptomatic resulting in approximately 421,000 surgeries each year. This compares to an estimated 1.5 million Americans with kidney stones resulting in approximately 180,000 extracorporeal shockwave lithotripsy procedures each year.

The filing with the FDA contains the request that the Medstone STS, in combination with Actigall therapy be indicated for use in fragmenting and eliminating symptomatic, radiolucent, non-calcified gallstones less than 20 mm in maximum diameter. It is estimated that approximately 1.2 million Americans are in this group.

Actigall is ursodiol USP (ursodeoxycholic acid), a naturally occurring bile acid. The medication was cleared for marketing in 1987 to treat patients with radiolucent, noncalcified gallbladder stones less than 20 mm in greatest diameter in whom elective cholecystectomy would be undertaken except for the presence of increased surgical risk, or for those patients who refuse surgery.

In 1996, it was cleared to prevent gallstones in obese patients experiencing rapid weight loss. The most common side effects observed in trials with Actigall were constipation, diarrhea and headache.

Medstone, as the only vertically integrated extracorporeal shockwave therapy (ESWT) company, is focused on providing cost effective lithotripsy for the treatment of renal stones and expanding the application of ESWT to other diseases such as gallstones and non-healing bone fractures. (See our Web site on the Internet http://www.medstone.com). -0-

NOTE TO EDITORS: This news release contains forward-looking information. The forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. The matters discussed in this announcement contain forward-looking statements that involve risks and uncertainties, including the timely development and market acceptance of new products, the development and rate of growth of new markets and procedures, including the fee-for-service, the impact of competitive products, technologies and pricing, the effect and timing of relevant regulatory approvals and other risks detailed from time to time in each company's respective public disclosure filings with the U.S. Securities and Exchange Commission (SEC).

CONTACT: Medstone International Inc.

David V. Radlinski

714/448-7700, Ext. 235