FDA Grants Priority Review Status To Orphan Medical's Xyrem

Minneapolis, MN - Oct. 17, 2000 - Updated 12/4/2000

Orphan Medical, Inc. (Nasdaq: ORPH) announced today that the Food and Drug Administration (FDA) has granted the Company's Xyrem(R) (sodium oxybate) oral solution New Drug Application (NDA) priority review status. This status obligates FDA to a goal of acting on the NDA within six-months from the date of submission. The FDA grants priority review status for new drugs that represent a significant advancement over available therapies. The NDA for Xyrem was submitted on October 2, 2000, to the FDA, which has sixty days from the date of submission to accept or reject it for review.

On December 4, 2000, Orphan Medical announced that the FDA had accepted the NDA for Xyrem for filing, within the 60 day window of the priority review process. Final approval for the use of Xyrem could come in mid-2001.

The Xyrem NDA requests approval as a treatment for the symptoms of narcolepsy, a chronic neurological disorder. In particular, Xyrem is intended to treat cataplexy and to improve the symptoms of excessive daytime sleepiness. Narcolepsy is accompanied by fragmented sleep throughout a 24-hour period whereas persons without the disease usually have more consolidated and organized sleep at night. The symptom of excessive daytime sleepiness afflicts all narcolepsy patients.

"We are pleased by the FDA's issuance of priority review status to Xyrem, and stand ready to assist the FDA with its review of the NDA in any way we can," said John Bullion, Orphan Medical CEO. "We consider Xyrem to be an important medicine and, upon FDA approval, it will allow patients a new means of controlling their narcolepsy symptoms. On the basis of our interpretation of the clinical data, we postulate that Xyrem has nocturnal effects on sleep that reduce the severity of narcolepsy symptoms during normal waking hours."

"Other activities relating to Xyrem are on schedule," continued Bullion. "The closed loop distribution system designed to minimize diversion is now well defined. Clinical studies relating to the NDA are complete, and patients are being entered into a double-blind trial (IIIb) study that is designed to further define Xyrem's effects on the daytime sleepiness symptom of narcolepsy."

Stimulants are currently used to address excessive daytime sleepiness associated with narcolepsy. Because stimulants do not treat cataplexy, tricyclic antidepressants and serotonin selective-reuptake inhibitors are usually prescribed in an attempt to control this symptom. Long-term treatment with these agents can be problematic due to limited efficacy, tolerance, and adverse side effects such as dry mouth, weight gain, tachycardia, and loss of libido. Because these agents suppress REM sleep, abrupt cessation of treatment can result in "rebound" of the REM-related symptom of cataplexy, to an incidence greater than pre-treatment levels.

Orphan Medical acquires, develops, and markets pharmaceuticals of high medical value for inadequately treated and uncommon diseases. The Company serves three strategic therapeutic market segments characterized by well-defined patient populations and served by physician specialists: Oncology Support, Antidotes and Sleep Disorders. Orphan Medical's Internet Web site address is http://www.orphan.com.