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 Synta Pharmaceuticals (NASDAQ:SNTA.DL), a biopharmaceutical company focused on small-molecule therapies to treat cancer and chronic inflammatory diseases, tanked as much as 21% after announcing one-year follow-up results for its Galaxy-1 trial over the weekend for ganetespib as a second-line treatment of non-small-cell lung cancer.

So what: According to Synta Pharmaceuticals' press release, 65% of the overall survival events for its final analysis have occurred so far, and up to this point delivered an overall survival hazard ratio of 0.75 in chemosensitive NSCLC patients. In other words, ganetespib in combination with docetaxel reduced the risk of death from the docetaxel monotherapy arm by 25%. It also delivered a median overall survival improvement of 3.3 months to 10.7 months as compared to just 7.4 months in the docetaxel control group.

Now what: The data doesn't seem horrible on the surface, but HSP90 inhibitors like ganetespib, which affects proteins that are crucial for cancer cell development, have lofty expectations built in by investors and are expected to deliver incredible results. I believe most investors and analysts are looking for a death reduction benefit somewhere in the 30% to 35% range, which is not what ganetespib delivered here. Now don't get me wrong; that doesn't mean Synta's drug is a lost cause by any means. However, with the company currently testing ganetespib in a phase 3 setting (Galaxy-II trial) with data due out next year, investors are a little skeptical now as to whether the death reduction benefit is going to be significant enough to merit an approval from the Food and Drug Administration. Keeping today's data in perspective, I'm perfectly happy adding Synta to my watchlist and sticking to the sidelines until we at least have the top-line phase 3 data.