I've always wondered what would happen if a drugmaker developed a drug and nobody noticed -- or cared.

I think I just found out.

On Thursday morning, MannKind (NASDAQ:MNKD) announced positive results from its final two phase 3 trials for its inhaled insulin product, Afresa, and its stock ended the day at the exact same price it did the day before. Maybe when the tree falls in the empty forest, it really doesn't make any sound.

After Exubera -- Nektar Therapeutics (NASDAQ:NKTR) and Pfizer's (NYSE:PFE) inhaled insulin product -- was deemed a marketing failure and Novo Nordisk (NYSE:NVO) and Eli Lilly (NYSE:LLY) ditched their programs, investors are rightfully a little worried about the chance of marketing success.

The more immediate question is whether Afresa will even make it to the market -- the drug does have to get past the Food and Drug Administration, after all. I don't think that MannKind has to worry about data about its effectiveness, but the safety-conscious FDA could send it back to the drawing board after it submits its marketing application early next year. There was a higher incidence of lung cancer in patients treated with Exubera versus the control group in a long-term safety analysis and, while MannKind hasn't seen any kind of signal of the same, it's usually easier to prove that something exists than that it doesn't.

With a market cap of $300 million, the risk/reward on MannKind, a Motley Fool Hidden Gems Pay Dirt pick, is looking just about right to me. The company could double from here should it gain marketing approval, and then double or triple again if the drug tops the paltry sales that Pfizer managed with Exubera. That's a lot of reward, but the unpredictable FDA introduces a lot of risk into the equation as well. If you're going to invest, buy carefully on the dips.

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Novo Nordisk is a Global Gains pick. Pfizer and Eli Lilly are Income Investor selections. Pfizer is also an Inside Value pick, and the Fool owns shares of it. 

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.