Boston Scientific Announcces Sub-Population Data from Enteryx® Study
and New Orleans, LA (May 20, 2004) -- Boston Scientific Corporation (NYSE: BSX) today announced sub-population data from a 12-month, 117-patient study of the Enteryx procedure for patients suffering from Gastroesophageal Reflux Disease (GERD) symptoms. David A. Johnson, M.D., Professor of Medicine, Chief of Gastroenterology at Eastern Virginia School of Medicine and the study's Principal Investigator, presented findings Wednesday supporting the conclusion that Enteryx is equally effective in controlling the symptoms of GERD in patients previously treated with proton pump inhibitor (PPI) medications at both standard and high dosing. The Company made the announcement at the annual Digestive Disease Week (DDW) conference, the largest international gathering of physicians, researchers, and academics in the fields of gastroenterology, hepatoloty, endoscopy and gastrointestinal (GI) surgery.

Patients from both high and standard PPI dosage groups responded comparably to the Enteryx procedure, with no statistically significant differences observed in three measures used to rate the severity of GERD symptoms, including the elimination or reduced reliance on PPIs. Comparing patient groups who had previously been treated with PPIs at either standard or higher dosing levels, the results showed that:

- 89 percent of high-dose and 82 percent of standard-dose patients were able to significantly reduce or eliminate the need for daily PPIs;
- PPI use improvement results showed no statistically significant differences between groups (p=0.461); and
- GERD health-related quality of life (HRQL) improvement results showed no statistically significant differences between groups (p=0.406).

"A patient who uses higher doses of PPI therapies could be as suitable a candidate for the Enteryx procedure as a standard-dose patient, giving physicians a wider selection of treatment options," said Dr. Johnson. "Additionally, as previously published, the cost implications for patients who require the sustained use of high-dose prescription PPIs is considerable. Interventive strategies, which have the potential for avoidance of this high-dose requirement, could have associated cost savings for these patients."

"These results support the utility of Enteryx as a viable treatment option for a broad range of PPI-dependent patients who suffer from GERD symptoms," said Michael Phalen, President of the Endoscopy business at Boston Scientific. "We are looking forward to increasing the market awareness and understanding of the potential benefits of the Enteryx procedure."

In April 2003, the U.S. Food and Drug Administration approved the Enteryx procedure for the treatment of symptoms of GERD in patients responding to and requiring daily pharmacological therapy with PPI medications.

Boston Scientific is a worldwide developer, manufacturer and marketer of medical devices whose products are used in a broad range of interventional medical specialties. For more information, please visit:

This press release contains forward-looking statements. The Company wishes to caution the reader of this press release that actual results may differ from those discussed in the forward-looking statements and may be adversely affected by, among other things, risks associated with the commercialization of new technologies, competitive offerings, intellectual property and other factors described in the Company's filings with the Securities and Exchange Commission.