The most disastrous, if least surprising, news from Pfizer's (NYSE:PFE) third-quarter earnings announcement yesterday was its surrender of the rights to market inhalable-insulin treatment Exubera to developer Nektar Therapeutics (NASDAQ:NKTR). The compound may be a flop commercially, but for one unexpected drugmaker, it's been a bonanza.

Pfizer and Nektar have previously stated that sales of Exubera have been dismal since its FDA approval in January 2006. Yesterday, Pfizer revealed just how dismal. In the first nine months of 2007, the diabetes treatment generated $12 million in sales, with $7 million of that in the most recent quarter. That's a far cry from the $2 billion blockbuster Pfizer predicted Exubera would eventually become, even as recently as this year.

Besides the millions of dollars Pfizer wasted in marketing Exubera, it also paid developer Nektar more than $100 million in just the first two quarters of 2007 to manufacture the drug and further research it.  

It would be easy to dub other inhalable insulin developers, like MannKind (NASDAQ:MNKD), Novo Nordisk (NYSE:NVO) or Eli Lilly (NYSE:LLY), the winners here. After all, they've just lost a large pharma rival. But it's still not clear that their compounds won't share the same concerns Exubera raised regarding long-term pulmonary safety or insurer formulary coverage.

No, the one clear winner from this debacle is Sanofi-Aventis (NYSE:SNY), for which Exubera has been a billion-dollar blockbuster. A few weeks before the FDA approved the treatment in early 2006, Sanofi agreed to give up its co-marketing rights to the drug in exchange for $1.3 billion from Pfizer.

In hindsight, it's easy to see that Pfizer overpaid for full marketing rights to the drug. Even more ironically, just last week, Pfizer was rumored as a possible buyer for Sanofi. If the rumors are true, for the sake of Pfizer's investors, let's hope it won't overpay Sanofi twice in two years.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool's disclosure policy never overpays.