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.

Let's take a look at the top stories in biotech and health care this morning -- keep an eye out for Agenus Inc (NASDAQ:AGEN), GlaxoSmithKline (NYSE:GSK) and Synta Pharmaceuticals (NASDAQ:SNTA)

GlaxoSmithKline's lung cancer vaccine fails in late-stage study
Shares of pharma giant GlaxoSmithKline are down around 2% in premarket this morning after announcing that its experimental MAGE-A3 cancer vaccine failed to meet a pair of primary co-endpoints in a late-stage trial as a potential treatment for non-small cell lung cancer (NSCLC). Agenus Inc, who made the adjuvant for the vaccine, is bearing the brunt of this bad news, as shares are down almost 19% in premarket.

The analysis released this morning shows that MAGE-A3 did not significantly extend disease-free survival compared to placebo in two different subpopulations afflicted with NSCLC. GlaxoSmithKline does plan to continue the trial to see if another subpopulation can be identified that might benefit from the vaccine. What's key to understand is that this is the second clinical failure for MAGE-A3, which was once thought to be a crown jewel of GlaxoSmithKline's pipeline. As such, you shouldn't place much hope on the vaccine ultimately finding a successful niche and going on to become a major revenue driver.

What's particularly noteworthy is that today's news marks GlaxoSmithKline's third clinical failure of a top clinical prospect in the last 12 months. Last fall, the company's experimental heart drug darapladib and Duchenne muscular dystrophy drug drisapersen both failed in late-stage trials. Drisapersen has since been handed back to its original developer, Prosensa Holding (NASDAQ:RNA), where they have performed a variety of new analyses in hopes of finding a reason to submit the drug for approval. Overall, GlaxoSmithKline continues to have a rough go on the clinical front in terms of high profile clinical candidates.  

Synta up big on breast cancer trial news
Developmental stage biotech Synta Pharmaceuticals is up 19% in premarket this morning after the company released interim results from a proof-of-concept study for ganetespib. The results are being presented at the 9th European Breast Cancer Conference (EBCC) in Glasgow, Scotland. For those of you new to this story, ganetespib is a selective inhibitor of heat shock protein 90 and is being investigated as a potential treatment for metastatic breast cancer.

What's impressive about this morning's movement in Synta's shares is that the analysis is very preliminary, and the study is still enrolling patients. So, even though today's presentation contains some promising signals for efficacy in terms of the number of metabolic responses observed, it is still early days for the company's lead experimental candidate. Given that cancer drugs in general have a poor track record in the clinic, you may therefore want to take a wait and see approach with this one.

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George Budwell has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.