MannKind (Nasdaq: MNKD) is trading down 40% today after announcing the Food and Drug Administration again turned down its application to market Afrezza, its inhaled insulin product.

Even at the knocked-down price, I wouldn't touch it with a 10-foot poll.

It's not because I don't think Afrezza should be on the market; I think it's a great product that could help diabetics. But the combination of a schizophrenic FDA and a cocky management has me still worried about the approvability of Afrezza.

This is the second time the FDA has turned down Afrezza. The first time, the FDA wanted an explanation about its "clinical utility." This time, the issue seems to be a problem with a switch from the MedTone device that was used in the clinical trials to a new device called the Dreamboat, which MannKind thinks is better.

Instead of laboratory experiments to prove the two devices are equivalent, the agency wants MannKind to run two clinical trials -- one in type 1 and one in type 2 diabetics -- to prove that the new device works as well as or better than the previous one. Amylin Pharmaceuticals (Nasdaq: AMLN), Eli Lilly (NYSE: LLY) and Alkermes (Nasdaq: ALKS) ran into a similar problem when they switched the manufacturing of Bydureon between the clinical trial and the commercial stages. Unlike MannKind, the companies got the information from the FDA before they submitted their first marketing application and were able to submit the appropriate clinical trial data.

It's not entirely clear whether MannKind just ignored the FDA's advice that a clinical trial would be needed to compare the two devices or whether the agency changed its requirements midstream.

What is clear is that management is confident -- perhaps overly so -- in the device. Perhaps it should come as no surprise from a man who names a company after himself, but CEO Alfred Mann is a little too cocky for my taste. In response to an analyst's question during last night's conference call about what the company planned to do if MedTone ended up being superior to Dreamboat in the clinical trials, Mann responded, "First of all, the answer is it won't be superior. The Dreamboat device is clearly superior in many ways." There was no part two.

Now don't get me wrong, Mann -- and all his money -- are certainly an asset to the company. I listed him as one of the strengths in my SWOT analysis of the company. But being cocky and not having a backup plan, even if the likelihood of needing one is slim, is not the kind of trait I dream about in a CEO.

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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.