Ultragenyx shares more than double in IPO debut

NEW YORK (AP) — Shares of Ultragenyx have more than doubled in their trading debut after the drug developer's initial public offering raised $121 million.

The Novato, Calif., company is developing several possible treatments for rare or extremely rare diseases, including Sly Syndrome, a cellular and organ dysfunction that typically leads to death by early adulthood.

Ultragenyx Pharmaceutical Inc. sold 5.8 million shares at $21 each, well above its mid-January forecast of 4.8 million shares going for $14 to $17.

The stock climbed $24 to $45 per share in midday trading Friday.

Two other drug developers debuted on the public market Friday: Trevena Inc., which raised about $64.8 million, and Cara Therapeutics Inc. in a $55 million IPO.

Trevena stock is off 6.1 percent and Cara shares are up almost 21 percent.