UPDATED: Prosensa harvests $78M as biotech IPOs continue to sizzle

Prosensa picked the right day to price its IPO. The Dutch biotech rang up the offering at $13 a share, at the top of the range, raising $78 million after bumping the number of shares on offer to 6 million. And after the stock ($RNA) started trading on Nasdaq this morning, the price shot straight up to $20.

Just hours before the pricing, GlaxoSmithKline ($GSK) rushed out a release announcing that the FDA had provided a verbal confirmation that it is providing "breakthrough drug" status for drisapersen, the Duchenne muscular dystrophy drug that was licensed from Prosensa. The drug--one of two closely watched programs racing to become the first approved treatment for DMD--is now in a pivotal trial.

The successful IPO was also a rare win for the European biotech community. While U.S. biotechs have been scrambling to dive through the newly-opened IPO window, the European drug development crowd has largely been sitting it out on the sidelines. Prosensa, though, did it by jumping into Nasdaq--the first such cross-Atlantic leap for a biotech in about 10 years, according to CEO Hans Schikan.

"There's more breadth and depth in the U.S. investment community," Schikan tells FierceBiotech today, explaining the IPO strategy. The IPO cash now gives the company at least a two-year runway to pursue the 5 other DMD programs it is working on, including two in the clinic with a third being advanced into human studies in the next few months.

Prosensa was named a Fierce 15 company last year.

Hans Schikan, CEO of Prosensa

The FDA made it clear that they were giving drisapersen the breakthrough drug designation because of the positive Phase II data that had been collected on 53 boys afflicted with DMD. For boys in the continuous treatment group after 24 weeks, there was a mean improvement over baseline of 31.5 meters in the 6-minute walking test, according to Glaxo's scientists. In the placebo arm there was an average decline of 3.6 meters at 24 weeks. After 48 weeks of therapy there was an average improved walking distance of 11.2 meters compared to a 24.7 meter mean decline in the placebo arm--a swing of about 36 meters.

The drug has also spurred proteinuria in clinical trials, raising concerns about potential side affects. But Schikan says that investigators have now had the chance to gather data on 300 patients, completed a Phase II placebo-controlled study and tracked some of these patients for four years. "In that context one should see a benefit/risk comparison," he adds.  

But Glaxo isn't alone in the clinic. Sarepta ($SRPT) has been earning rave reviews for the promising data it's seen from a tiny trial for eteplirsen that recruited only a dozen boys. Now the biotech is looking for the FDA to signal whether an accelerated approval is possible as it considers an early IND, and a crowd of investors is watching every twist and turn in this race as Sarepta's stock gyrates between $35 and $40 a share. The stock slipped 4% in yesterday's trading.

Oddly, Sarepta CEO Chris Garabedian has said the company never filed for a breakthrough drug designation, a decision he may be regretting today.   

- here's the press release

Special Report: Prosensa – 2012 Fierce 15

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