The roughly $230 million raised by Dendreon ( DNDN) Thursday night was the second largest follow-on stock offering by a biotech company in 2009 -- a year in which money raised by the sector overall is down significantly. That's a pretty good indication of strong demand from institutional investors for a piece of Dendreon and its prostate cancer vaccine Provenge. Only Vertex Pharmaceuticals ( VRTX) was able to price a larger stock offering this year, raising $320 million in February. After that sits Dendreon, followed by Cadence Pharmaceuticals ( CADX) ($86 million), Seattle Genetics ( SGEN) ($56 million), Allos Therapeutics ( ALTH) ($49 million) and Geron ( GERN) ($46 million), according to Burrill & Co., a San Francisco-based life sciences merchant bank. No one should be surprised that Dendreon chose to sell company stock to raise money. After last week's Provenge data presentation, CEO Mitch Gold was upfront about the company's plans to raise money in two ways -- both through a stock sale and by partnering Provenge's ex-U.S. commercial rights. Gold was more circumspect about the timing of a stock sale, but generally speaking, biotech companies try to raise money when they can -- when the demand for the stock is high -- and not when the money is desperately needed. In this case, Dendreon was able to sell 10.7 million shares with a 1.27 million-share over-allotment in an overnight deal handled by Deutsche Bank Securities. The company hasn't yet announced pricing, but the deal reportedly went off at $19.20 a share. That's at the high end of the range in which the stock was being offered Thursday night and a minuscule 3% discount to Dendreon's closing price of $19.76.