Shares of InterMune (NASDAQ:ITMN) tumbled by more than 15% today, as the company is suffering from a possible trial data leak from a competitor's idiopathic pulmonary fibrosis drug, which successfully passed its phase 3 trials, and put up solid data. David points to one analyst from Summer Street who quickly came to InterMune's defense, saying that while the two drugs are technically competitors, patients would be cycled between them, given the nature of the IPF disease.

In this segment, Motley Fool health-care analyst David Williamson takes a look at ITMN today, a stock he sees as one that could vary wildly up or down by 50% based on what happens with its drug Esbriet. He talks investors through both scenarios, and also discusses what strong trial data vs. weak could mean for the company, and when investors may see results.

David Williamson 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.