Clinical Data Shows Enterra Therapy from Medtronic Reduces Symptoms of Gastroparesis.

Business Editors/Health/Medical Writers

MINNEAPOLIS--(BUSINESS WIRE)--Aug. 5, 2003

Gastric electrical stimulation with pacemaker-like device

proven to improve quality of life in patients

suffering from debilitating disorder

According to newly reported research in the current issue of Gastroenterology (Vol. 125, No. 2), high-frequency, low-energy gastric electrical stimulation (GES) of the stomach with Enterra(TM) Therapy from Medtronic, Inc. (NYSE:MDT), reduces many of the symptoms associated with the most severe form of gastroparesis -- a disorder frequently associated with diabetes that is characterized by delayed stomach emptying, and by persistent nausea and vomiting.

"The results of this clinical study have definitively demonstrated the promise of gastric electrical stimulation for patients whose lives are seriously affected by one of the world's most tragic diseases," said Dr. Thomas Abell, a professor of medicine at the University of Mississippi School of Medicine, Jackson, Miss., and lead author of the study. "Gastric electrical stimulation is an important treatment option for patients with gastroparesis who no longer respond to standard medication."

Gastroparesis can occur when the nerves controlling movement of food through the digestive system are damaged. Subsequently, weakened muscle contractions of the stomach result in abnormally slow movement of food through the gastrointestinal (GI) tract, causing chronic symptoms of fullness, bloating, nausea or vomiting.

Gastroparesis patients cannot eat normally, may lose weight and may require a feeding tube for nutritional support. Severe gastroparesis is especially troubling for people with Type I diabetes in whom delayed gastric emptying, and chronic nausea and vomiting, make glycemic control a challenge. In some cases the cause of gastroparesis is idiopathic (of unknown origin) or related to prior gastric surgery involving vagotomy.

Enrolling 33 patients (17 with diabetes and 16 idiopathic) over a year-long period, clinicians at 11 U.S., European and Canadian medical centers set out to investigate the efficacy of GES for the treatment of gastroparesis as a part of the Worldwide Anti-Vomiting Electrical Stimulation Study (WAVESS). Inclusion criteria included: vomiting frequency of more than seven times a week (median 17.3 episodes); greater than 60 percent retention of food in the stomach two hours after eating and 10 percent retention after four hours; symptoms of gastroparesis for periods of longer than 12 months; and patients who were unresponsive to standard medical therapy.

The study was divided into two phases. Phase I of the study consisted of a two-month, randomized, placebo-controlled, double-blinded, crossover trial, with each patient having his or her stimulator turned ON for a month and OFF for a month without either the patient or physician knowing the status. Investigators found that vomiting frequency among patients was significantly reduced during the ON months, with a 50 percent further decrease compared to OFF months. As might be expected, the majority of patients preferred to have it ON rather than OFF.

In Phase II, all stimulators were turned ON (with patient and physician knowledge). Patients were evaluated at six and 12 months for vomiting frequency, upper GI symptoms, gastric emptying, quality of life and adverse events.

The researchers found additional significant outcomes during Phase II at the six- and 12-month follow up sessions. Vomiting frequency decreased more than 80 percent for patients with and without diabetes. Other upper GI symptoms -- including vomiting and nausea severity, bloating, abdominal pain and early satiety -- also significantly improved in both groups, with the diabetic group seeing the greatest reduction in vomiting and nausea severity and the idiopathic group improving significantly in vomiting severity and abdominal pain.

Although gastric emptying was only moderately accelerated, quality of life scores improved in both patient groups after one year. Specifically, scores comparing patients' lives before and after receiving Enterra Therapy showed reductions in bodily pain and improvements in physical functioning, general health, vitality and social functioning.

Four patients experienced problems that necessitated removal of their stimulation devices during the first year, including two patients with infections. One patient required surgery to re-position the device.

"The symptoms of gastroparesis are so severe that these patients become debilitated. Enterra Therapy provides new hope for these young patients -- 20-65 years old -- by returning them to their functional personal and professional lives," said Dr. Richard McCallum, director of the Center for Disorders of Gastrointestinal Nerve and Muscle Function at the University of Kansas School of Medicine in Kansas City, Kan., and corresponding author for the WAVESS study group. "It is the most impressive long-term result for gastroparesis that I have seen during the 25 years I have studied gastroenterology."

Study investigators estimate that up to 50 percent of those referred for the treatment of gastroparesis may be candidates for Enterra Therapy after conventional medical therapy has failed to bring relief.

Performed under general anesthesia, Enterra Therapy uses an implanted medical device -- similar to a pacemaker -- to deliver mild electrical pulses to the stomach. Through laparoscopy or laparotomy, two electrodes are attached to the wall of the stomach and connected to the device, which is placed in the abdominal wall under the patient's skin. On average, the battery life of the device is five to 10 years depending on the required level of stimulation.

Enterra Therapy became available in the United States in March 2000 when the U.S. Food and Drug Administration (FDA) granted Medtronic a Humanitarian Device Exemption (HDE) -- a special regulatory clearance intended to benefit patients by treating or diagnosing a rare disease or condition. It became commercially available in Europe in March 2002 when it received CE (Conformite europeenne) Mark.

Enterra Therapy is just one component of the Medtronic suite of technologies available worldwide for the diagnosis and treatment of gastrointestinal conditions. It is complemented by the Bravo(TM) pH Monitoring System, a catheter-free, 48-hour pH testing system for the diagnosis of acid reflux.

Medtronic, Inc. (www.medtronic.com), headquartered in Minneapolis, is the world's leading medical technology company, providing lifelong solutions for people with chronic disease. More information about gastroparesis and Enterra Therapy can be found at www.enterratherapy.com.

Any statements made about the company's anticipated financial results and regulatory approvals are forward-looking statements subject to risks and uncertainties such as those described in Medtronic's Annual Report on Form 10-K for the year ended April 25, 2003. Actual results may differ materially from anticipated results.

NOTE TO EDITORS: In the term "Conformite europeenne" noted in this news release there should be acute accents over the "e" in "Conformite" and the second "e" in "europeenne." This symbol may not appear properly in some systems.