Inhaled insulin for the treatment of diabetes

This review examined the safety and effectiveness of technosphere insulin for the treatment of diabetes. The authors concluded that technosphere insulin is safe and effective in reducing blood glucose levels at meals.

Insulin (a hormone which reduces blood glucose levels) replacement therapy is used in the treatment of type 1 diabetes (T1D) and type 2 diabetes (T2D). The most common method of administering insulin is via subcutaneous (under the skin) injection. There are many types of insulin available for injection. They can be classified as rapid-acting, short-acting or long-acting. Rapid-acting insulin is injected at meals and reduces blood glucose levels quickly. Rapid-acting insulin, such as insulin aspart (Novorapid), remains in the blood for 4 hours. Long-acting insulin is injected once daily and remains in the blood for 24 hours.

Due to injection discomfort or fear of injections, some patients may prefer to inhale insulin. Afrezza (TI – Technosphere Insulin Inhalation System) is currently the only inhaled insulin available for the treatment of T1D and T2D. It is a rapid-acting insulin which is inhaled at meals. It is inhaled into the lungs using an oral inhaler and is then absorbed into the blood.

This review summarized results from clinical trials which examined the safety and effectiviness of TI.

One trial examined the safety and effectiveness of TI for the treatment of T1D. Participants in this trial received either inhaled TI or subcutaneous insulin aspart. The reduction in HbA1c was similar in both groups, but tended to be higher with insulin aspart. However, participants treated with TI had a greater reduction in fasting plasma glucose levels (blood glucose levels in an individual who has not eaten anything for 8 hours). Participants treated with a TI also experienced less hypoglycemia (dangerously low blood glucose levels) and had less body weight gain.

In T2D patients, TI led to a 0.4% decrease in HbA1c compared to placebo (substance with no effect on the body). T2D patients, however, gained an average of 0.49 kg. 

The most common side effects observed in clinical trials investigating TI were cough and throat pain/irritation. However, the cough decreased over time.

One trial reported small changes in lung function after 2 years of TI treatment. These changes were reversed upon discontinuing TI. However, these changes were unlikely to have any meaningful effect on the lungs and the lung function did not progressively decrease.

This review concluded that TI is well-tolerated and effective in reducing blood glucose levels at meals.

Although the clinical trial discussed in this review did not observe any meaningful changes in lung function with TI treatment, the long-term effects (more than 10 years) of TI treatment on the lungs is unknown.