Orphan Medical Offers Update on Xyrem Clinical Trials

Minneapolis, MN - Jan. 9, 2001

In a presentation today at the annual J.P. Morgan H&Q Healthcare Conference, Orphan Medical announced results from an additional supporting clinical trial for Xyrem(R) (sodium oxybate) oral solution.

This new controlled clinical trial demonstrates that the efficacy of Xyrem is sustained over extended periods of time. Patients who had been treated with Xyrem for periods between 9 months to 4 years entered a single-blinded baseline period during which their existing dose of Xyrem was continued and baseline cataplexy incidence was established. These patients were then randomly assigned in double-blinded fashion to two weeks of either placebo or continued Xyrem dosing.

There was no change in the median incidence of cataplexy in those patients continuing Xyrem treatment, whereas there was a median increase of 21 cataplexy attacks in the placebo group. This difference between the active drug group and the placebo group is statistically significant. Moreover, the increase in cataplexy incidence in the placebo group was gradual over the two weeks of the trial, rather than an acute rebound response that can occur with tricyclic antidepressant medications currently used to treat cataplexy. There was no indication of physical or chemical dependence in patients whose long-term Xyrem treatment was abruptly discontinued.

"The results of this trial support Xyrem's safe and efficacious use as a treatment for narcolepsy," said John Bullion, Orphan Medical's Chairman and Chief Executive Officer. "These trial results and the data of our previous trials have been submitted as part of the New Drug Application (NDA) now under priority review by the Food and Drug Administration (FDA). We anticipate the agency will announce the determination of its review early in the second quarter of this year."

"We are very pleased," continued Bullion, "with the Company's 2000 sales, growing about 70% over 1999 revenues. Our 2001 revenues will continue to show strong growth with the approval of Xyrem."

Narcolepsy is a chronic neurological disorder affecting an estimated 100,000 to 125,000 Americans, whose main symptoms are excessive daytime sleepiness and cataplexy. Narcolepsy is accompanied by fragmented sleep throughout a 24-hour period whereas persons without the disease usually have more organized sleep at night. The symptom of excessive daytime sleepiness afflicts all narcolepsy patients.

Cataplexy is a debilitating symptom characterized by loss of muscle control in response to strong emotional reactions such as laughter, anger, or surprise. In its most severe form, cataplexy can cause a person to collapse during waking hours. The Company submitted a New Drug Application (NDA) requesting approval for Xyrem as a treatment for narcolepsy, particularly cataplexy and to improve the symptoms of excessive daytime sleepiness, on October 2, 2000.