The development of insulin inhalers was highlighted by the BBC television programme "Watchdog Healthcheck" on July 3. The programme described an inhaler developed by Inhale Therapeutics Systems and co-promoted by Aventis Pharma and Pfizer. Phase III trials of the product are underway in the US.
Inhale's insulin inhaler is a dry powder formulation. According to the company, the inhaler uses a mechanical device that eliminates the need for breath-activation and stops the particles sticking together. The mechanism involves compressed air being forced into a chamber where the insulin powder forms a cloud for inhalation. Inhale says that the device gives accurate and reliable dosing and that, as the chamber is clear, the patient can see when all the insulin has been inhaled. The device is about 10 inches long.
The company reported phase II results at the American Diabetes Association annual meeting in Texas last month which showed that long-term measurement of blood glucose control remained stable in patients at 30 months and that lung function was also stable for the duration of treatment. Further phase II data was presented at the Endocrine Society's annual meeting in Toronto, Canada, on June 24, which suggested that, in terms of glucose control, the inhaled insulin was comparable with subcutaneous insulin injection administration. Further information about the product can be found on the company's website (http://www.inhale.com/).
Other insulin inhalers are being developed, including one by Novo Nordisk and Aradigm Corporation which is entering phase III trials.
Mr Simon O'Neill (head of care developments, Diabetes UK) told The Journal on July 3: "An insulin inhaler could greatly improve quality of life for people with diabetes, freeing them from some of the constraints of having to inject. Hopefully this would also mean that people would be less inclined to miss injections and so would maintain better control of their diabetes. However, the best-case scenario is that these products may be available in a few years and, until all the trials have been completed, we will not know whether they will have any adverse side effects or who they will be suitable for."
Diabetes UK said that there were issues concerning the effectiveness of inhaled insulins. These included the fact that insulin inhalers often used large doses. The potential side effects of such high doses needed to be evaluated as did the effects of the insulin that was not absorbed. Diabetes UK commented that the inhalers developed so far did not eliminate the need for injections since longer-acting injections were still required.
"Watchdog" suggested that an insulin inhaler may be launched in two years but Aventis/Pfizer were unable to confirm this.