Investors were downright giddy that Exelixis (Nasdaq: EXEL) will finally have data for its cancer drug cabozantinib soon. The company said yesterday that it had reached the pre-specified number of events to end the trial testing cabozantinib in patients with medullary thyroid cancer. Shares jumped over 9%.

I'm not sure why the shares moved; the company said the data would be delayed three months from its previous prediction of the middle of the year. By my math, that's right around now. Exelixis still needs to crunch the numbers and expects to be able to have the data available for public viewing early in the fourth quarter, which technically starts just 23 days from now.

Most likely, investors are just rushing into the next potential binary event in the biotech space. There's nothing wrong with that, I guess, but they could have bought a few weeks ago at a substantial discount to today's price.

What's the likelihood that the trial comes back positive? It's hard to say. Cabozantinib has demonstrated activity in multiple types of cancer including medullary thyroid cancer. But the types of patients enrolled in the phase 3 trial are, on average, sicker than those enrolled in the earlier 1/2 trial, which makes predicting the results a little more difficult.

My guess is that the data will come back positive and the delay was due to cabozantinib slowing the progression of the cancer more than Exelixis would expect. But that's just an educated guess based on the data to date.

If cabozantinib fails to show an effect in medullary thyroid cancer, it'll be disappointing, but it's not the end of the world for Exelixis. That type of cancer is fairly rare and isn't going to propel the drug to blockbuster status. Although the prostate cancer market has more competition -- from Johnson & Johnson's (NYSE: JNJ) Zytiga, Dendreon's (Nasdaq: DNDN) Provenge, and Sanofi's (NYSE: SNY) Jevtana -- it also offers a lot more patients. A phase 3 trial set to get under way in the fourth quarter is substantially more important to Exelixis' long-term success than the medullary thyroid cancer trial.

Tick-tock. Tick-tock.

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Fool contributor Brian Orelli holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Johnson & Johnson, Dendreon, and Exelixis. Motley Fool newsletter services have recommended buying shares of Exelixis and Johnson & Johnson, as well as creating a diagonal call position in Johnson & Johnson. 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.