In June 2014, the United States Food and Drug Administration (FDA) approved the inhaled insulin called Afrezza for use in the treatment of type 1 diabetes. Afrezza is a rapid-acting insulin that is taken at mealtimes. Unfortunately, there’s no word yet on when we might see this form of inhaled insulin approved in Canada.
Did you know that another inhaled insulin has already been licensed for use in both Canada and the U.S.? Although approved by both Health Canada and the FDA, it has never been marketed, meaning that no one is selling it.
Confused? Let’s go back in time! About 10 years ago, the pharmaceutical manufacturer Pfizer introduced its form of inhaled insulin – called Exubera – to the Canadian marketplace. Exubera was already being used in the U.S., and was just about to hit the pharmacy shelves in Canada, when the company decided not to continue to market the inhaled insulin.
Why? At that time, it was quite expensive (far more costly than other insulins) and there was a requirement that people using Exubera had to have frequent tests (called pulmonary function tests), to make sure that inhaling this powdered form of insulin was not harming their lungs. So, the costs of the insulin, plus the frequent lung function tests, were starting to become complicated and very expensive. Besides, the number of patients who were actually using inhaled insulin was low.
Still, while Pfizer was going through all of these issues with Exubera, another drug company, Mannkind, continued to work on its inhaled insulin and, finally, Afrezza is now available in the U.S.
Since we already have Pfizer’s inhaled insulin approved but not being used, why might this insulin be different? There are a couple of reasons. First, Afrezza has a much smaller delivery device than the one previously available, so it is much easier to administer. Second, the requirement for lung testing is not as frequent with Afreeza as it was with Exubera; in the U.S., people using Afreeza must have a pulmonary function test prior to use, after 6 months of use, after one year of use, and then every year after that (the test schedule might be different in Canada, if and when Afreeza is approved here).
It’s important to remember that Afreeza is indicated for use only for people with type 1 diabetes. Inhaled insulin is a mealtime insulin. It works similarly to currently available injectable mealtime insulins, however one disadvantage with inhaled insulin is that the dosage must be increased or decreased by 4 units at a time: the inhaler can only deliver doses of 4, 8 , 12, etc., units. There is no ability to adjust by one unit at a time, which sometimes leads to people either over- or under-dose, or eat or not eat, to compensate for glucose levels and amount of insulin delivered. It also makes taking a correction dose much more difficult.
What are the advantages? Well, that is easy to understand. Injecting insulin can be complicated and painful. For people administering multiple daily insulin injections, it may be difficult to find healthy injection sites. Using inhaled insulin can improve the quality of life for people using meal-time insulin and they may choose this type of insulin regimen to avoid the issues related to injections.
What is the future of inhaled insulin in Canada? At this time, Pfizer has no plans to resume selling Exubera. It is not clear right now whether Afrezza will be approved for use in Canada. But stay tuned – we will keep you posted!