Regado Biosciences went public at a price lower than expected back in May, and investors snapped up shares on IPO day.

Regado (Nasdaq: RDGO) soared more than 30 percent to $5.39 after priced its shares at $4 on Thursday.

By the close, RDGO  still showed some “pop,” closing at $4.70, or 17 percent. More than 300,000 shares traded hands.

In after-hours trading, Regado moved up again, hitting $5.

The company, a spinout of Duke University, did issue far more shares at a much lower price than it had anticipated in May.

The IPO is one of several for North Carolina biotech firms this year, including Quintiles (NYSE: Q).

Regado issued 10.75 million. It had been looking to raise $80 million or more in its IPO. In an updated filing with the SEC on May 31, Regado priced its shares at between $14 and $16 each.

Its lead product, REG1, targets blood clotting and would be used in coronary intervention. REG1 could be used in open heart surgery.

Regado’s DNA-based system could present an alternative to such drugs as Heparin and Coumadin, which help prevent heart attacks, strokes and deep-vein thrombosis but also increase the risk of uncontrolled bleeding.

Initial Plans

The company planned to offer 5 million shares.

Underwriters have the option of purchasing another 750,000 shares. Regado had also said in that filing it had investors already waiting to buy,

“Certain of our existing stockholders, including stockholders affiliated with certain of our directors, have indicated an interest in purchasing up to an aggregate of approximately $29.5 million in shares of our common stock in this offering at the initial public offering price,” Regado said in the filing.

“However, because indications of interest are not binding agreements or commitments to purchase, the underwriters could determine to sell more, less or no shares to any of these potential investors and any of these potential investors could determine to purchase more, less or no shares in this offering.”

The company, which is seeking to commercialize technology developed at Duke University, has raised more than $110 million in financing dating back to 2005.

Cowen and Company, BMO Capital Markets, Canaccord Genuity, Needham & Company and Wedbush PacGrow Life Sciences are working with Regado as underwriters.

Funds will be used to develop one treatment in a Phase 3 clinical trial called REG1.

Noting that it is an “emerging” company, Regado did not disclose all information typically supplied in an IPO filing.

“We are an ’emerging growth company’ as that term is used in the Jumpstart Our Business Startups Act of 2012 and, as such, have elected to comply with certain reduced public company reporting requirements for this prospectus and future filings,” the company said.

Regado raised $51 million in new financing, including backing from Triangle-based Aurora Funds, last December. The company closed on a “D” round of financing totaling just over $21.5 million in July of 2011. Regado has been raising the latest funding since December 2009.

Regado is based in New Jersey but maintains its research and development lab in Durham.

The firm landed a new investor in December, RusnanoMedInvest, which is part of a Russian government-owned investment firm called Rusnano.

Other investors included Baxter Ventures, which also is a new investor, along with previous backers Edmond de Rothschild Investment Partners, Domain Associates, Quaker Partners, Aurora and Caxton Advantage Life Sciences Fund.