By Jim Shrine

The FDA, citing rules on orphan drug exclusivity, declined to approve the Ares-Serono Group¿s Rebif as a treatment for multiple sclerosis (MS).

The agency decided Rebif (interferon beta-1a) did not offer the necessary clinical superiority to override orphan status held by existing MS drugs, most notably Biogen Inc.¿s Avonex (interferon beta-1a).

The decision was not surprising to many who follow the MS market. Some analysts expressed skepticism when Ares-Serono submitted its biological license application last spring. (See BioWorld Today, March 4, 1998, p. 1.)

¿Fundamentally, we believe this is good news because it reinforces our confidence that the FDA makes decisions on the merits of good science and clinical results,¿ said Lisa Easley, Biogen¿s manager, public relations. ¿It makes clear that Rebif does not offer greater efficacy and safety, and does not provide a significant additional benefit to patient care than currently available therapies.¿

Biogen¿s orphan drug exclusivity runs until May 2003.

Serono Laboratories Inc., a Norwell, Mass., affiliate of Geneva-based Ares-Serono, said in a news release the FDA also had questions about clinical data. The company said it planned to respond quickly to the FDA and continue discussions on the orphan drug issues.

Peter Ginsberg, senior research analyst at U.S. Bancorp Piper Jaffray Inc. in Minneapolis, said he doesn¿t see Ares-Serono¿s product posing a competitive threat to Avonex in the near future.

¿I don¿t think there¿s any chance of this being resolved soon,¿ Ginsberg said. ¿It unlikely Rebif will reach the U.S. market before 2003. And it is extremely unlikely it would reach the market in the near term [six to 12 months].¿

Ares-Serono officials could not be reached for comment. But they did discuss the issue with analysts in a conference call Tuesday.

Ginsberg said company officials spelled out two possible options: running a head-to-head study comparing Rebif and Avonex, or taking the issue to an FDA advisory committee. The company planned to discuss the issue further with the FDA before deciding how to proceed, he said.

The U.S. market is an important one for Avonex, which is the clear market leader among three approved products. The other two are Betaseron (interferon beta-1b), a product from Chiron Corp., of Emeryville, Calif., and Berlex Laboratories Inc., a U.S. subsidiary of Berlin-based Schering AG; and Copaxone, which is sold by Teva Pharmaceuticals Industries Ltd., of Jerusalem.

Sales of Avonex in 1998 totaled $394.8 million, with about $304 million of that coming in the U.S. Biogen reported earlier that more than 55,000 patients worldwide were on the drug at the end of 1998.

Ginsberg said the market share for Avonex over the past year has been 58 percent to 60 percent. For the past month or so, he said, the market shares were as follows: Avonex, 58 percent; Betaseron, 25 percent; and Copaxone, 17 percent.

¿We believe Biogen can actually grow that share to 60 percent-plus in 1999,¿ Ginsberg said. ¿Given that Rebif will not be reaching the U.S. market, that makes us more confident regarding that presumption. We believe the share gains we see from Avonex will be at the expense of Copaxone.¿

Biogen¿s stock (NASDAQ:BGEN) gained $1.375 Tuesday to close at $103.625. n