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 biotechnology company Medivation (Nasdaq: MDVN) are off to the races today -- currently up 27% -- following positive data from the company's experimental drug prostate cancer drug.

So what: Medivation and development partner Astellas Pharma released results last night revealing that MDV3100, its experimental oral prostate cancer drug, was well-tolerated in phase 3 clinical trials and it significantly extended survival rates over the placebo (18.4 months vs. 13.6 months). The drug met its efficacy goals of slowing or stopping the progression of the disease with very few, minor side effects.

Now what: Don't count your chickens before they're hatched, because MDV3100 still needs to make it past the FDA, but things are definitely looking good. MDV3100 offered a better survival rate versus placebo than Johnson & Johnson's (NYSE: JNJ) Zytiga (4.8 months vs. 3.9 months), and there's speculation that, if approved, MDV3100 could be used as a pre-chemotherapy treatment in conjunction with Dendreon's (Nasdaq: DNDN) Provenge treatment. This is one of those cases where the science is fascinating, but the approval has pretty much been baked into the stock price. With Medivation's stock up 324% since Nov. 2, I just don't see any value left in the stock – at least not right now.

Craving more input? Start by adding Medivation to your free and personalized watchlist so you can keep up with the latest news from the company.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.