As Jeff Hwang wrote in February, Elan (NYSE:ELN) and Biogen IDEC (NASDAQ:BIIB) were to file for approval of Antegren much earlier than expected. Yesterday, the companies announced that they had submitted a Biologics License Application (BLA) to the FDA for Antegren in the treatment of multiple sclerosis (MS). So the ball is now officially rolling. If Antegren is approved, Biogen IDEC and Elan will share the profits equally.

Well before Biogen merged with IDEC Pharmaceuticals, it was a leader in the multiple sclerosis field. Avonex was launched in 1996, and on its back Biogen became one of the few biotech companies to become a profitable business operation. Avonex is a true blockbuster with $1.2 billion in sales last year, but it's a mature product and the company needs a follow-up drug, such as Antegren, to drive growth into the future.

The Antegren BLA filing in MS comes about a year earlier than the initial time line for the drug's development. Biogen IDEC and Elan are conducting two phase III clinical trials. These trials are to assess the effects of Antegren after two years of treatment.

What's interesting is that Biogen IDEC and Elan are filing for approval after having just one year of treatment data in hand (though they are going to finish the trials). While the companies are not disclosing this data to the public, a reasonable assumption would be that Antegren must have shown a statistically significant benefit on the efficacy endpoints after one year of treatment. Perhaps the clinical benefit to patients is so clear that they believe approval will be granted without having two years of data.

Of course, this is just my speculation, but the way I'm thinking about this is that if the Antegren data in MS was marginal at this time, there would be no way management would be taking the risk of filing early before the trials were complete. The hit to the companies' reputations and the class-action suits they would surely be slapped with would make filing without absolutely compelling data incredibly unwise. That means that shareholders in both companies likely have legitimate reasons to celebrate.

The Fool's Biotechnology discussion board is always hopping with interesting conversation. Check it out, on us, for 30 days.

Fool contributor Charly Travers does not own shares of any of the companies mentioned in this article.