Given the important role of insulin in the treatment of diabetes mellitus and in 
light of common barriers to insulin use, new strategies for insulin delivery by 
routes other than intravenous and subcutaneous injection have been investigated 
since the discovery of insulin in the 1920s. Most companies researching and 
developing pulmonary administration systems for the use of insulin announced the 
termination of product development following the failure of the first US 
FDA-approved inhaled insulin product, Exubera. One company in particular 
continued their pursuit of a useful inhaled insulin product. MannKind 
Corporation has developed a powder formulation of insulin that allows for a high 
percentage of the administered insulin to be absorbed via the lung. Their 
product, AFREZZA (Technosphere insulin), is currently under review by the FDA 
for use in patients with diabetes. Technosphere insulin appears to overcome some 
of the barriers that contributed to the market withdrawal of Exubera by the 
manufacturer. Studies with Technosphere insulin have shown it to be a unique 
insulin formulation in that it is very rapid acting, has a relatively short 
duration of action, and is efficacious in terms of improved glycemic control 
without contributing to increased weight gain or the incidence of hypoglycemia 
when compared with other prandial insulin products. Additionally, Technosphere 
insulin has demonstrated a favorable safety and tolerability profile in clinical 
studies to date.