MannKind (NASDAQ:MNKD) is back.

For the third time in four years, the biotech seeks to gain approval from the U.S. Food and Drug Administration for its inhaled insulin product Afrezza. MannKind announced the resubmission of the New Drug Application, or NDA, for Afrezza in treating type 1 and type 2 diabetes on Sunday. Here's what's next for the California-based company.

Source: MannKind.

1. Decisions, decisions
The first major decision impacting MannKind is whether the FDA will accept the Afrezza NDA for review. This one should be a slam dunk. MannKind has successfully jumped this hurdle in the past. There's no reason to think they won't do so this time around.

After that, the Prescription Drug User Fee Act, or PDUFA, date will be assigned. This date is the big one -- when the FDA actually makes an up-or-down decision on approval for Afrezza. What will happen? It's never a sure thing with the FDA, but I expect we'll see MannKind finally score a long-sought regulatory approval next August. 

2. Howdy, partner
MannKind hasn't hesitated to admit that it wants and needs a partner to help commercialize Afrezza. In May, Al Mann, founder and CEO of MannKind, said that the company was in discussions with multiple prospective partners. He also noted at that time that other interested parties indicated that they would resume due diligence efforts after the phase 3 clinical results were available. Those results were announced in August.

Which partner will MannKind land? My fellow Fool Max Macaluso suggested last year that Pfizer (NYSE:PFE) should jump aboard the Afrezza train. The big pharmaceutical company wants to expand its presence in the diabetes market. Pfizer could certainly benefit from adding a new drug with growth potential to its lineup. And partnering with other companies has been a key part of CEO Ian Reed's strategy.

I have stated in the past that Sanofi (NYSE:SNY) could be an even better fit for MannKind. The French drugmaker is already a leader in insulin products. But its blockbuster Lantus loses patent protection next year. Sanofi, like many other big pharmas, isn't shy about growing through partnership deals.

The truth is, of course, that we don't know yet which partner will align with MannKind. For that matter, MannKind might even sign up multiple partners for different geographical regions. I don't doubt, though, that the company will find someone willing to take on commercialization of Afrezza. I suspect we'll find out which partner steps up to the plate by summer of 2014.

3. To go boldly where no man has gone before
Technically, this old Star Trek line doesn't totally apply for MannKind. There have been previous attempts to develop and launch inhaled insulin products. Pfizer flopped miserably with its marketing of Exubera back in 2006 and 2007, ultimately taking a $2.8 billion loss.

Eli Lilly (NYSE:LLY) dropped its development of an inhaled insulin product in 2008 before phase 3 studies were even completed. The company cited "a thorough evaluation of the evolving commercial and clinical potential of the product compared to existing medical therapies" as a key reason for the move.

I think that MannKind has a better chance of success than its bigger brethren. In several respects, Pfizer and Lilly were banking primarily on the convenience of an inhaled insulin, which, in the case of Exubera, turned out to be not-so-convenient. MannKind appears to have resolved the problems that plagued Exubera. 

The more important distinctive that Afrezza has, though, its its mechanism of action. Afrezza acts rapidly and closely mimics the function of a healthy pancreas. My hunch is that this characteristic will appeal to physicians and the convenience factor of inhaled delivery will appeal to patients.  

The biggie
Of these three milestones that MannKind faces, securing a partner could be the biggest catalyst for the stock. FDA approval for Afrezza, while not a given, seems quite likely. The market expects a green light.

Which company (or companies) partner with MannKind, though, will be critical to how successful a commercial launch of Afrezza will be. An alliance with a major pharmaceutical firm with a large diabetes sales force could stack the deck in MannKind's favor. On the other hand, a partnership with a less-connected firm would likely disappoint investors.

Whatever happens, MannKind is in better shape this time around to succeed than ever before. If all goes well, Afrezza could potentially be a game-changer in diabetes. I recommend keeping your eyes on this stock in 2014.

Fool contributor Keith Speights 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.