Inhalable Insulin - Approval and Competing Drug Development

Approval and Competing Drug Development

Exubera is the brand name of first formulation of inhalable insulin to receive the US FDA approval. It is manufactured by Pfizer in collaboration with Nektar Therapeutics and is licensed for use by both type 1 and type 2 diabetics. However in the UK its use in under the National Health Service "should not be recommended because it could not be proven to be more clinically or cost effective than existing treatments", except under special circumstances. In April 2006, the UK's National Institute for Health and Clinical Excellence issued a preliminary statement advising against the use of inhalable insulin on the grounds that the benefits of avoiding injections did not justify the higher cost of the new product. At that time, NICE recommended use of the new drug only in clinical trials.

Concerns have been expressed by the Institute for Safe Medication Practices about a serious risk of dosing errors when prescribing Exubera. Insulin is traditionally prescribed in international units, but Exubera is prescribed in milligrams. 1 mg of Exubera is equivalent to 3 units of insulin, however, the increment is not linear: 3 mg of Exubera is equivalent to 8 units of insulin and not 9 units as might be expected, and the prescriber is strongly advised to refer to the manufacturer's conversion table before prescribing. Furthermore, because of retention of blister contents, three consecutive doses of 1 mg blisters of Exubera results in a higher dose of insulin than a single 3 mg blister of Exubera, further complicating prescribing calculations.

Exubera is considered a short or rapid acting insulin. In clinical studies, Exubera reached peak concentration levels faster than some insulins administered by injection. Thus, this form of insulin would begin working within the body faster than those forms of injected insulin. Type 1 and 2 diabetics will still need an injection of longer acting insulin to maintain a basal level for a 24 hour period.

As of October 18, 2007, Pfizer has announced that it will no longer manufacture or market Exubera. According to Chairman and CEO Jeffrey Kindler this is because Exubera "failed to gain acceptance among patients and physicians."

At the time of Exubera's discontinuation, several other companies were pursuing inhaled insulin including Alkermes working with Eli Lilly and Company, MannKind Corporation,, and Aradigm working with Novo Nordisk. However, by March 2008, all of these products had been discontinued except for MannKind’s Afrezza product. As of March 2010 Afrezza was still under FDA review.