Dendreon Corp. (DNDN) shares more than doubled in early morning trading, but this may be somewhat misleading.

Quick recap: Dendreon yesterday (Tuesday) released detailed results of its innovative prostate cancer drug Provenge. Ahead of the results, the stock first climbed steadily from $22.00 to about $24.50 at 1:24 p.m., only to plunge some 45 percent to $11.81 before trading was halted at 1:27 p.m. That's when Nasdaq's oversight body initiated a brief probe.

The Nasdaq Stock Market then e-mailed a statement, saying it will let stand two minutes' worth of transactions that it initially suspected were the result of a brokerage error. Trading resumed at 6:15 p.m. and shares immediately traded up over 120 percent to around $26.50.

This morning, shares opened at $26.82, but are now back at above $24 a share. The stock still registers over a 100 percent gain, but in actuality, the reaction to the Provenge news has been somewhat flat, likely because expectations were met.

Provenge, Dendreon said Tuesday, extended median survival in a large clinical trial by 4.1 months and increased three-year survival by 38 percent compared to a placebo (31.7 percent versus 23.0 percent). It surpassed the 22 percent goal required to meet FDA approval.

If, before the detailed results, analysts had estimated sales of Provenge would be $1 billion a year, now Lazard Capital Markets estimates sales would be $2 billion a year. This could provide serious top line growth to the biotech company and pave the way to more such treatments to other drugs.