Biogen Inc. (BGEN) has learned that as far as Orphan Drug exclusivity, sometimes you can have your cake and eat it too. Last week FDA ruled that Serono Laboratories Inc. cannot market its Rebif version of interferon beta-1a for multiple sclerosis in the U.S. until the orphan drug exclusivity period expires for BGEN's Avonex interferon beta-1a.

The shoe was on the other foot in 1996, when the FDA allowed Avonex on the U.S. market over the objections of Berlex Laboratories Inc., which had been awarded Orphan Drug status in 1993 for its Betaseron interferon beta-1b. Berlex (Wayne, N.J.) sued FDA, arguing that Avonex and Betaseron were identical products. By