More than 85 years after the discovery of insulin, patients will have a new alternative to injectable insulin. After years of testing, and doubt from the medical community that it would ever work, inhaled insulin (Exubera, Pfizer/Nektar) began arriving on pharmacy shelves in late August.
The Food & Drug Administration approved the dry powdered insulin in January for the treatment of adult patients with Type 1 and Type 2 diabetes. The launch was purposely delayed to train healthcare professionals on the inhaler's administration and maintenance, as the company built up inventory. A number of training sessions were held this past summer with endocrinologists, pharmacists, diabetes educators, and other healthcare providers.
One of the trainers was Stephen M. Setter, Pharm.D., CDE, associate professor of pharmacotherapy at Washington State University College of Pharmacy. He was concerned about using the device, but once he began practicing with it, he felt more at ease. "I've trained a lot of skeptical physicians, pharmacists, and nurses who approached this with a lot of hesitation," he said. "But once they got it in their hands and went through the process, their fears and biases tended to fade away."
The insulin is delivered through a 6-in. inhaler-about a foot long when it's fully extended. The complete kit includes one inhaler, one replacement chamber, 1 mg/180 blister pack or 3 mg/90 blister pack, and two release units. The retail price for the 1 mg/180 blister pack is about $150.
Clinicians were also trained on how to maintain the device. The inhaler needs to be replaced once a year, and the release unit needs to be replaced every two weeks and cleaned once a week with warm water and mild soap. Unlike injectable insulin, which needs to be refrigerated, inhaled insulin is kept at normal room temperature.
Inhaled insulin has been studied in several thousand patients. Studies showed that inhaled insulin is effective in diabetes patients and provides glycemic control comparable to traditional insulin regimens. However, researchers found that fewer than 30% of people with Type 1 diabetes were able to reduce their blood sugar to recommended levels after six months of treatment with inhaled insulin, and, as a result, inhaled insulin should be used in combination with longer-acting insulin in Type 1 patients. In Type 2 diabetes, inhaled insulin can be used alone or in combination with oral diabetes agents or longer-acting insulin.
One study compared the glycemic control achieved with inhaled insulin versus the sulfonylurea agent glibenclamide (glyburide) in 456 patients with Type 2 diabetes uncontrolled by metformin monotherapy. Researchers reported similar reductions in hemoglobin A1c. In patients with A1c levels above 9.5%, inhaled insulin provided superior blood glucose control to glibenclamide.
Many pharmacy experts foresee that patients who have been delaying the use of insulin due to fear of needles will certainly use inhaled insulin. Because inhaled insulin has a similar pharmacokinetic profile to rapid-acting insulin analogs, it will likely be prescribed to help control postprandial glucose. It is recommended that it be taken within 10 minutes of eating.
Zierler-Brown sees inhaled insulin being used primarily as add-on therapy to oral agents in patients who are still outside recommended A1c levels. She also suggested that inhaled insulin may be used as monotherapy for patients who fail to control blood glucose with diet and exercise alone.
However, Setter said that he doesn't expect inhaled insulin to be used as monotherapy in Type 2 patients because many patients do not go straight to insulin. "I see those patients starting on the oral agents and moving to a long-acting insulin and then adding a pre-meal insulin like an inhaled version," he said.
Setter also predicted that inhaled insulin may be used interchangeably with injectable insulin.