Source: MannKind

Drugmaker MannKind Corp. (MNKD 1.92%) and its marketing partner Sanofi (SNY -1.70%) have officially launched Afrezza, an inhaled insulin, to the market. If Afrezza is able to live up to its full potential, it could pose a serious threat to the sales of several currently-available short acting insulins. Drugs like NovoLog and Humalog, which are currently sold by Novo Nordisk (NVO -2.00%) and Eli Lilly and Co. (LLY -1.63%), respectively, currently drive billions of dollars in revenue, so you can bet they are taking the threat that Afrezza poses seriously.

Novo and Lilly have certainly known about inhaled insulin for a long time, as both companies had previously devoted resources to developing their own inhaled insulins. However, they both ended up abandoning their inhaled insulins projects while they were still in development. Novo didn't think that the product held enough commercial potential. Lilly stated that the regulatory environment at the time was too uncertain to continue development, and also mentioned uncertainties about its commercial potential. 

One of the key benefits that Afrezza can claim over currently-available rapid acting insulins is that it goes to work very quickly, reaching peak levels within 12 to 15 minutes. This compares quite favorably to NovoLog and Humalog, which by comparison reach peak insulin levels within 45 to 90 minutes after injection. Faster absorption is important -- blood sugar levels can spike after eating a meal, so having the insulin work quickly can help patients better control their blood sugar levels. 

However, a few companies have been working on injectable meal time insulins that work faster than NovoLog and Humalog currently do. If these drugs can eventually find their ways to the market, it may reduce one of the key selling advantages that Afrezza has going for it.

While companies like Halozyme Therapeutics Inc have announced clinical studies of very rapid acting insulins, MannKind investors probably need to keep the closest watch on Novo's pipeline. Novo Nordisk currently lists NN1218, an insulin analog that is intended to provide faster onset than NovoLog, in Phase 3 development on its website. While the company has yet to file the drug for approval with the FDA, if Novo can eventually get the drug to market it could potentially knock out one of the key selling advantages that Afrezza currently claims.

We don't know how much faster NN1218 absorption is when compared to NovoLog, so there is still is a good chance that even if the drug can find its way to the market Afrezza would remain the fasting absorbing meal time insulin. But Novo Nordisk is a diabetes powerhouse with billions of dollars in sales at stake, and they have the scale, resources, and motivation to compete effectively against an inhaled insulin.

It will still be some time before MannKind will see a potential faster acting insulin get to market, and the company has plenty of near term challenges ahead with the launch of Afrezza, particularly after disappointing initial sales figures. However, if MannKind and Sanofi can clear the marketing and adoption hurdle, investors need to be aware of what is in other drugmakers' pipelines -- especially ones that could be real threats to Afrezza. Until we get more information about how the market is reacting to Afrezza's availability, and about the clinical progress of these potential incoming threats, I'll personally continue to curiously watch MannKind from the sidelines.