Biogen Idec raised its full-year guidance today, based largely off strong launch sales of MS pill Tecfidera.

The Weston, MA, biotech brought in sales of $1.7 billion for 2Q, an increase of 21% from last year’s second quarter. Tecfidera alone posted $192 million in sales. In an investor note today, ISI Group analyst Mark Schoenebaum called Tecfidera’s debut the “holy mother of all launches,” as it’s outpaced the launch numbers for rival MS orals Gilenya from Novartis in 2010 and Aubagio from Sanofi/Genzyme last year.

In a press release, Biogen Idec estimated that $82 million of that revenue came from channel inventory, and $110 million was the result of pent-up demand. Analysts had originally expected Tecfidera’s sales to come in at $70 million for the period.

Older treatment Tysabri, meanwhile, missed its guidance, something Schoenebaum attributes to Tecfidera switchers. 

Oral treatments for MS aren’t just stealing share from older treatments (although analysts had expected a fair amount of that, too). They are also growing the market. According to research and advisory firm Decision Resources, the multiple sclerosis market is expected to grow 10% annually through 2018.

Tecfidera will “capture more than $4 billion in 2018 sales in the United States, France, German, Italy, Spain, the United Kingdom and Japan,” the advisory firm said. “The MS market stands at the beginning of a fundamental restructuring…we expect each new therapy to establish its own clinical niche, noted Georgiana Kuhlmann, senior business analyst for the firm.

This does not mean any brand is safe, though.

“Tysabri missed and this was driven, in part, by switching to Tecfidera,” Schoenebaum added. “These are likely JCV positive patients who have been on Tysabri for 2+ years who had no other viable options prior to Tecfidera’s launch.”

Tysabri has a boxed warning for the JC (John Cunningham) Virus which can lead to progressive multifocal leukoencephalopathy (PML)—a potentially fatal viral disease. Schoenebaum estimates Tysabri cannibalization will taper off within the next few months, as “the ‘pool’ of JCV+ patients who have been on Tysabri for 2 years is depleted.”

One of the other orals has come under scrutiny recently. Novartis’ Gilenya is currently under a probe by the Department of Justice for alleged financial kickbacks to physicians. In response to a reporter’s question about the charges, the company told MM&M, “We can confirm that Novartis Pharmaceuticals Corporation (NPC) received a Civil Investigative Demand…requesting the production of documents and information relating to marketing practices for Gilenya, including the remuneration of healthcare providers. NPC is cooperating with this civil investigation.”

Gilenya posted Q2 sales of $468 million but quarterly sales growth of 65% shows it’s been losing steam. The first-quarter sales brought a 70% increase, and the last quarter of 2012 saw sales spike 72% over the prior-year period. Sanofi’s oral MS contender, Aubagio, saw Q1 sales of $26 million this year.