Berlex's U.S. BETASERON Secondary-Progressive Multiple Sclerosis Study Stopped Early.

MONTVILLE, N.J.--(BUSINESS WIRE)--Sept. 13, 1999--

- Study Patients to be Offered the Option to Receive BETASERON(R)-

Berlex Laboratories, Inc. announced today that it will stop its U.S.BETASERON(R) (Interferon beta 1-b) secondary-progressive multiple sclerosis (SPMS) study based on the recommendation of the Independent Monitoring Board (IMB). The IMB determined that the probability is very small that the primary outcome will change with the small amount of additional data collection between now and the original planned study end. The IMB also recommended that all patients enrolled in the study be given the opportunity to receive BETASERON(R) at the currently approved dose. As always, the decision to begin treatment should be based on the best judgement of the patient and his/her physician, on individual patient needs, and on the best medical wisdom.

In order to protect the integrity of the SPMS study, results will not be made available to Berlex until the final analyses are completed after data base lock. The placebo-controlled study was expected to run through March 2000. Clinical investigators will continue to compile data throughout the remainder of this year until all patients have come to their last visit for closure of the study. Patients who elect to switch from the double-blind study to active treatment with BETASERON(R) will continue to be medically monitored by their clinical investigators. Berlex will provide BETASERON(R) at no cost to these patients.

BETASERON(R) was the first therapy approved for the treatment of relapsing-remitting multiple sclerosis. About 50 percent of people with the relapsing-remitting disease advance into the secondary-progressive form. BETASERON(R) is already approved for secondary-progressive MS in Europe, Canada and Australia. In these areas it is the only approved therapy for the treatment of both the relapsing-remitting form as well as the more advanced, secondary-progressive form of multiple sclerosis.

In the U.S., no therapy is currently approved for secondary-progressive multiple sclerosis. Berlex Laboratories and its manufacturing partner Chiron Corporation filed a Supplemental Biological License Application (BLA) with the U.S. Food & Drug Administration (FDA) in June 1998, seeking a secondary-progressive indication for BETASERON(R) in the U.S. This submission is based on data from the European SPMS study. The European study showed that BETASERON(R), given at the same dose used to treat relapsing-remitting MS, slowed progression of disability in people with the advanced secondary-progressive form of the disease. In addition to actively reviewing the European data, Berlex expects that the FDA will consider the U.S. trial results in their review.

Committed to developing novel therapeutics that address unmet medical needs, Berlex Laboratories, Inc. researches, develops, manufactures, and markets ethical pharmaceuticals in three strategic areas: Diagnostic Imaging, Female Healthcare, and Therapeutics for life-threatening and chronic, disabling diseases. Berlex business divisions are located in Montville and Wayne, New Jersey, and in Richmond, California. For more information about the company please visit our website: www.berlex.com. To learn about MS and Berlex-sponsored patient support programs, please visit www.betaseron.com or call MS Pathways at 1-800-788-1467.