Second biotech IPO in a week comes in below target.

Hyperion Therapeutics became a public company on July 26 after pricing 5 million shares of its common stock at $10 per share. The price fell just below its $11 to $13 target range. It was the second life sciences IPO in a week, following quickly on the heels of Durata Therapeutics’ offering, which also fell short of its target range.

The South San Francisco-based biotech raised $50 million, the amount it had expected to raise by increasing the shares offered, and began trading on the Nasdaq Global Select market under the ticker HPTX. Venture backers Sofinnova, New Enterprise Associates, Highlands Capital Partners, Bay City Capital, and Panorama Capital were expected to buy $22 million of the offering, according to Renaissance Capital.

Hyperion is focused on the treatment of rare diseases of the liver. The company’s lead product, Ravicti, is in development for two orphan indications—urea cycle disorders and hepatic encephalopathy. It has a PDUFA date with the U.S. Food and Drug Administration of October 23 as a treatment for urea cycle disorders, a condition that affects about one in every 10,000 newborns.

Of the eight biotechs that have gone public in 2012, only two have priced in their target range. But while the hoped for price hasn’t matched what investors are willing to pay, the companies have performed fairly well in the aftermarket with the average performance of the group up 32.8 percent above their IPO price. Supernus Pharmaceuticals, which went public at the beginning of May, is up 159 percent, the best performer so far among all U.S. IPOs in 2012.

The eight therapeutics companies that went public in 2011 have also been performing fairly well. Only two among them priced within their target range, but as of July 27, the group is up an average of 28.9 percent over the IPO price.

Right now there are eight drug developers in the IPO queue. Although the IPO market remains challenging, the aftermarket performance of the companies that have gone public in the past couple of years, along with reduced regulatory compliance requirements brought on by the recently enacted JOBS Act, could ease the way for private companies to access public funding.

Deals for the Week Ending July 27, 2012 : Sheet1