The current review was designed to compare between the insulin inhalation 
systems Exubera and Afrezza and to investigate the reasons why Exubera was 
unsuccessful, when Afrezza maker is expecting their product to be felicitous. In 
January 2006, Pfizer secured FDA and EC approval for the first of its kind, 
regular insulin through Exubera inhaler device for the management of types 1 and 
2 diabetes mellitus (DM) in adults. The product was no longer available to the 
market after less than two years from its approval triggering a setback for 
competitive new inhalable insulins that were already in various clinical 
development phases. In contrary, MannKind Corporation started developing its 
ultra-rapid-acting insulin Afrezza in a bold bid, probably by managing the 
issues in which Exubera was not successful. Afrezza has been marketed since 
February, 2015 by Sanofi after getting FDA approval in June 2014. The results 
from this systematic review indicate the effectiveness of insulin inhalation 
products, particularly for patients initiating insulin therapy. Pharmaceutical 
companies should capitalize on the information available from insulin inhalation 
to produce competitive products that are able to match the bioavailability of 
subcutaneous (SC) insulin injection and to deal with the single insulin unit 
increments and basal insulin requirements in some diabetic patients or extending 
the horizon to inhalable drug products with completely different drug entities 
for other indications.