Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Dendreon Corporation (NASDAQ:DNDN), a biotechnology company focused on developing novel immunotherapeutic cancer solutions, fell as much as 24% after reporting disappoint second-quarter earnings results.

So what: For the quarter, Dendreon delivered $73.3 million in sales, which was 8% below what it reported at this time last year, and a narrower loss of $68.8 million, or $0.45 per share. Wall Street, on the other hand, expected a smaller loss of $0.42 per share and $75.6 million in revenue. The miss here was bad enough to merit downside action in the share price today, but the real pessimism built when Dendreon noted that Provenge, its prostate cancer immunotherapy, wouldn't see year-over-year growth. That's bad news for a drug that's only been on the market a few years and was projected to be a blockbuster in treating metastatic prostate cancer.

Now what: What a mess is all I can say. I selected Dendreon as a turnaround candidate in my One Person's Trash Is Another Person's Treasure portfolio on the premise that it would get Provenge approved in Europe and it'd maintain low double-digit sales gains in the United States. However, increasing competition from Johnson & Johnson's Zytiga and Medivation's Xtandi has halted its progress dead in its tracks. Even if Provenge gets approved in the EU (which it should based on the EMA panel's positive opinion on the drug), it may run into the same pricing concern issues that crippled its sales potential early on in the U.S. For now, Dendreon needs to keep focusing on reducing costs and, I believe, seek out a marketing partner in Europe that'll help launch this product if and when it's approved.

Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

The Motley Fool owns shares of, and recommends Johnson & Johnson. It also owns shares of Dendreon. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.